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Spud and FLML: generalising and automating the user interfaces of scientific computer models  

NASA Astrophysics Data System (ADS)

The interfaces by which users specify the scenarios to be simulated by scientific computer models are frequently primitive, under-documented and ad-hoc text files which make using the model in question difficult and error-prone and significantly increase the development cost of the model. We present a model-independent system, Spud[1], which formalises the specification of model input formats in terms of formal grammars. This is combined with an automatically generated graphical user interface which guides users to create valid model inputs based on the grammar provided, and a generic options reading module which minimises the development cost of adding model options. We further present FLML, the Fluidity Markup Language. FLML applies Spud to the Imperial College Ocean Model (ICOM) resulting in a graphically driven system which radically improves the usability of ICOM. As well as a step forward for ICOM, FLML illustrates how the Spud system can be applied to an existing complex ocean model highlighting the potential of Spud as a user interface for other codes in the ocean modelling community. [1] Ham, D. A., Spud 1.0: generalising and automating the user interfaces of scientific computer models, Geosci. Model Dev. Discuss., 1, 125-146, 2008.

Ham, D. A.; Farrell, P. E.; Maddison, J. R.; Gorman, G. J.; Wilson, C. R.; Kramer, S. C.; Shipton, J.; Collins, G. S.; Cotter, C. J.; Piggott, M. D.



Assessing Usability of Human-Machine Interfaces for Life Science Automation Using Computational Cognitive Models  

Microsoft Academic Search

The objective of this study was to assess the plausibility of using computational cognitive models for evaluating the usability of human–machine interfaces in supervisory control of high-throughput (biological) screening (HTS) operations. Usability evaluations of new interface prototypes were conducted by comparisons with existing technologies. Model assessment occurred through comparison with human test results. Task completion times and the number of

David B. Kaber; Rebecca S. Green; Sang-Hwan Kim; Noa Segall



Adaptation in automated user-interface design  

Microsoft Academic Search

Design problems involve issues of stylistic preference and flexible standards of success; human designers often proceed by intuition and are unaware of following any strict rule-based procedures. These features make design tasks especially difficult to automate. Adaptation is proposed as a means to overcome these challenges. We describe a system that applies an adaptive algorithm to automated user interface design

Jacob Eisenstein; Angel R. Puerta



Automation Interfaces of the Orion GNC Executive Architecture.  

National Technical Information Service (NTIS)

This viewgraph presentation describes Orion mission's automation Guidance, Navigation and Control (GNC) architecture and interfaces. The contents include: (1) Orion Background; (2) Shuttle/Orion Automation Comparison; (3) Orion Mission Sequencing; (4) Ori...

J. Hart



Semi-automated in vivo solid-phase microextraction sampling and the diffusion-based interface calibration model to determine the pharmacokinetics of methoxyfenoterol and fenoterol in rats.  


In vivo solid-phase microextraction (SPME) can be used to sample the circulating blood of animals without the need to withdraw a representative blood sample. In this study, in vivo SPME in combination with liquid-chromatography tandem mass spectrometry (LC-MS/MS) was used to determine the pharmacokinetics of two drug analytes, R,R-fenoterol and R,R-methoxyfenoterol, administered as 5 mg kg(-1) i.v. bolus doses to groups of 5 rats. This research illustrates, for the first time, the feasibility of the diffusion-based calibration interface model for in vivo SPME studies. To provide a constant sampling rate as required for the diffusion-based interface model, partial automation of the SPME sampling of the analytes from the circulating blood was accomplished using an automated blood sampling system. The use of the blood sampling system allowed automation of all SPME sampling steps in vivo, except for the insertion and removal of the SPME probe from the sampling interface. The results from in vivo SPME were compared to the conventional method based on blood withdrawal and sample clean up by plasma protein precipitation. Both whole blood and plasma concentrations were determined by the conventional method. The concentrations of methoxyfenoterol and fenoterol obtained by SPME generally concur with the whole blood concentrations determined by the conventional method indicating the utility of the proposed method. The proposed diffusion-based interface model has several advantages over other kinetic calibration models for in vivo SPME sampling including (i) it does not require the addition of a standard into the sample matrix during in vivo studies, (ii) it is simple and rapid and eliminates the need to pre-load appropriate standard onto the SPME extraction phase and (iii) the calibration constant for SPME can be calculated based on the diffusion coefficient, extraction time, fiber length and radius, and size of the boundary layer. In the current study, the experimental calibration constants of 338.9±30 mm(-3) and 298.5±25 mm(-3) are in excellent agreement with the theoretical calibration constants of 307.9 mm(-3) and 316.0 mm(-3) for fenoterol and methoxyfenoterol respectively. PMID:22884205

Yeung, Joanne Chung Yan; de Lannoy, Inés; Gien, Brad; Vuckovic, Dajana; Yang, Yingbo; Bojko, Barbara; Pawliszyn, Janusz



Automated Student Model Improvement  

ERIC Educational Resources Information Center

Student modeling plays a critical role in developing and improving instruction and instructional technologies. We present a technique for automated improvement of student models that leverages the DataShop repository, crowd sourcing, and a version of the Learning Factors Analysis algorithm. We demonstrate this method on eleven educational…

Koedinger, Kenneth R.; McLaughlin, Elizabeth A.; Stamper, John C.



Towards Automation of User Interface Design.  

National Technical Information Service (NTIS)

This paper suggests an approach to automatic software design in the domain of graphical user interfaces. There are still some drawbacks in existing user interface management systems (UIMS's) which basically offer only quantitative layout specifications vi...

R. Gastner G. K. Kraetzschmar E. Lutz



Automate discovery of deep web interfaces  

Microsoft Academic Search

With the rapid increase of web sources, more and more deep web databases become available. The information in these databases can only be accessed by submitting queries to back-end databases. However, the traditional search engine interfaces resemble extremely deep web interfaces. Therefore, it is difficult to distinguish them and to find deep web interfaces. This paper proposes a novel method

Xin Du; Yongqing Zheng; Zhongmin Yan



Automating metadata generation: the simple indexing interface  

Microsoft Academic Search

In this paper, we focus on the development of a framework for automatic metadata generation. The first step towards this framework is the definition of an Application Programmer Interface (API), which we call the Simple Indexing Interface (SII). The second step is the definition of a framework for implementation of the SII. Both steps are presented in some detail in

Kris Cardinaels; Michael Meire; Erik Duval



A virtual object manipulation interface for automated assembly programming  

Microsoft Academic Search

This paper describes the implementation of a novel robotic workcell programming interface that allows an assembly designer to obtain immediate feedback regarding the manufacturability of his design. The interface allows the user to manipulate the three-dimensional CAD\\/CAM models of the components and “assemble” them into the final product. The computer then analyzes the relevant assembly operations and translates them into

Akihiro Sato; A. A. Maciejewski



Aircraft automation: the problem of the pilot interface.  


Aircraft operations, particularly in the IFR environment, are rapidly becoming very complex. Studies have shown that this complexity can frequently lead to accidents and incidents. Results of studies performed at NASA and elsewhere are presented to show that one of the major themes evident in both the accidents and incidents and in the research performed to solve the problems associated with them is that of human error. Examples of various incidents and blunders, recorded in several studies, illustrate and emphasize the hypothesis: "As systems become more and more automated and complex, the more they become prone to human error. The problem can be eliminated or reduced only if good human factor principles are incorporated in the implementation of the systems, to guarantee a good man/machine interface". Aircraft systems technology, however, (e.g.: electronics, avionics, automation) is evolving and developing at a very high rate. Examples of research are presented showing where this emerging technology has been employed to reduce the complexity and enhance the safety and utility of the aircraft operations. PMID:3985891

Bergeron, H P; Hinton, D A



Automated semiconductor modeling  

NASA Astrophysics Data System (ADS)

A procedure is presented for the automatic creation of diode and transistor models used by the circuit and systems analysis computer program SUPER*SCEPTRE. A Hewlett Packard 9816s microcomputer and 4145B semiconductor parameter analyzer are used to control the process.

Tobak, John P.



Semi-Automated Linking of User Interface Design Artifacts  

Microsoft Academic Search

User centered design involves the creation of design artifacts such as task and architecture models, typically by people with different backgrounds using inconsistent terminology. Communication between user interface designers can potentially be improved if the viewpoints represented by these design artifacts can be correlated. This research demonstrates how different design artifacts can be linked semi-automatically. We illustrate this technique using

Said Elnaffar; Nicholas C. Graham



Model 215 Automated Glycerlization and Deglycerolization ...  

Center for Biologics Evaluation and Research (CBER)

... Product: Model 215 Automated Glycerolization and Deglycerolization System. ... Advisory Committees; Science & Research; Regulatory Information; ... More results from


High-Level Modeling and Design of Asynchronous Interface Logic  

Microsoft Academic Search

Asynchronous digital interface circuits exhibit a high degree of concurrency. Self-timedimplementation is the most appropriate design discipline for such circuits. Their complexitydemands that a formal design methodology, amenable to automation, is used to designthem. Existing specification models suffer from severe limitations when it comes to describingthe circuit function at a high level, which requires decomposing the specification intointercommunicating sub-modules and




Operator directed common conceptual models for advanced aircraft automation  

Microsoft Academic Search

The incorporation of advanced flight automation systems into modern aircraft has resulted in an increase in errors in interaction with aircraft automation. A prior study identified the lack of a simple, consistent model of the automation as a contributing component and found pilots creating their own ad-hoc models of aircraft automation. The design of new, complex automation system requires a

Sanjay S. Vakil; R. John Hansman



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

SciTech Connect

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

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



Model - based User Interface Design  

Microsoft Academic Search

Abstract This work is about supporting user interface design by means of explicit design representa tions, in particular models We take as a starting point two different development traditions: the formal, analytic, top down engineering approach and the informal, synthetic, bottom are based on specific design representations tailored to the respective approaches, and are found to have strengths and weaknesses



Automated EEG feature selection for brain computer interfaces  

Microsoft Academic Search

A brain computer interface (BCI) utilizes signals derived from electroencephalography (EEG) to establish a connection between a person's state of mind and a computer based signal processing system that interprets the EEG signals. The choice of suitable features of the available EEG signals is crucial for good BCI communication. The optimal set of features is strongly dependent on the subjects

Michael Schroder; Martin Bogdan; T. Hinterberger; N. Birbaumer



Automation and Accountability in Decision Support System Interface Design  

Microsoft Academic Search

When the human element is introduced into decision support system design, entirely new layers of social and ethical issues emerge but are not always recognized as such. This paper discusses those ethical and social impact issues specific to decision support systems and highlights areas that interface designers should consider during design with an emphasis on military applications. Because of the

M. L. Cummings


A methodology for automated fuzzy model generation  

Microsoft Academic Search

In this paper we propose a generic methodology for the automated generation of fuzzy models. The methodology is realized in three stages. Initially, a crisp model is created and in the second stage it is transformed to a fuzzy one. In the third stage, all parameters entering the fuzzy model are optimized. The proposed methodology is novel and generic since

Markos G. Tsipouras; Themis P. Exarchos; Dimitrios I. Fotiadis


User interface design principles for the SSM/PMAD automated power system  

NASA Astrophysics Data System (ADS)

Martin Marietta has developed a user interface for the space station module power management and distribution (SSM/PMAD) automated power system testbed which provides human access to the functionality of the power system, as well as exemplifying current techniques in user interface design. The testbed user interface was designed to enable an engineer to operate the system easily without having significant knowledge of computer systems, as well as provide an environment in which the engineer can monitor and interact with the SSM/PMAD system hardware. The design of the interface supports a global view of the most important data from the various hardware and software components, as well as enabling the user to obtain additional or more detailed data when needed. The components and representations of the SSM/PMAD testbed user interface are examined. An engineer's interactions with the system are also described.

Jakstas, Laura M.; Myers, Chris J.



Microsoft Academic Search

In this contribution we discuss interface conditions for unsaturated flow in porous media. Typical applications are subsurface flow and technical applications like fuel cells. After an analysis of suitable interface conditions at the contact interface of two porous materials of different kind, we introduce a model for outflow boundary conditions at the interface of a porous material with open space.

Mario Ohlberger; Ben Schweizer


Task-focused modeling in automated agriculture  

NASA Astrophysics Data System (ADS)

Machine vision systems analyze image data to carry out automation tasks. Our interest is in machine vision systems that rely on models to achieve their designed task. When the model is interrogated from an a priori menu of questions, the model need not be complete. Instead, the machine vision system can use a partial model that contains a large amount of information in regions of interest and less information elsewhere. We propose an adaptive modeling scheme for machine vision, called task-focused modeling, which constructs a model having just sufficient detail to carry out the specified task. The model is detailed in regions of interest to the task and is less detailed elsewhere. This focusing effect saves time and reduces the computational effort expended by the machine vision system. We illustrate task-focused modeling by an example involving real-time micropropagation of plants in automated agriculture.

Vriesenga, Mark R.; Peleg, K.; Sklansky, Jack



A Method for Automated Detection of Usability Problems from Client User Interface Events  

PubMed Central

Think-aloud usability analysis provides extremely useful data but is very time-consuming and expensive to perform because of the extensive manual video analysis that is required. We describe a simple method for automated detection of usability problems from client user interface events for a developing medical intelligent tutoring system. The method incorporates (1) an agent-based method for communication that funnels all interface events and system responses to a centralized database, (2) a simple schema for representing interface events and higher order subgoals, and (3) an algorithm that reproduces the criteria used for manual coding of usability problems. A correction factor was empirically determining to account for the slower task performance of users when thinking aloud. We tested the validity of the method by simultaneously identifying usability problems using TAU and manually computing them from stored interface event data using the proposed algorithm. All usability problems that did not rely on verbal utterances were detectable with the proposed method.

Saadawi, Gilan M.; Legowski, Elizabeth; Medvedeva, Olga; Chavan, Girish; Crowley, Rebecca S.



Automated detection of chorio-scleral interface using polarization-sensitive optical coherence tomography  

NASA Astrophysics Data System (ADS)

A polarization sensitive optical coherence tomography based automated algorithm for segmentation of the chorio-scleral interface is presented. The algorithm employs a two-step segmentation approach. At first, local birefringence based segmentation with low precision is performed to roughly distinguish the choroid and sclera. Successively, a depth oriented slope fitting to phase retardation is applied in both the choroid and sclera. The interface is determined as the cross-point of the two phase retardation slope lines. The algorithm shows potential for functional, objective, and volumetric choroid thickness measurement.

Duan, Lian; Yamanari, Masahiro; Yasuno, Yoshiaki



RCrane: semi-automated RNA model building  

PubMed Central

RNA crystals typically diffract to much lower resolutions than protein crystals. This low-resolution diffraction results in unclear density maps, which cause considerable difficulties during the model-building process. These difficulties are exacerbated by the lack of computational tools for RNA modeling. Here, RCrane, a tool for the partially automated building of RNA into electron-density maps of low or intermediate resolution, is presented. This tool works within Coot, a common program for macromolecular model building. RCrane helps crystallographers to place phosphates and bases into electron density and then automatically predicts and builds the detailed all-atom structure of the traced nucleotides. RCrane then allows the crystallographer to review the newly built structure and select alternative backbone conformations where desired. This tool can also be used to automatically correct the backbone structure of previously built nucleotides. These automated corrections can fix incorrect sugar puckers, steric clashes and other structural problems.

Keating, Kevin S.; Pyle, Anna Marie



RCrane: semi-automated RNA model building.  


RNA crystals typically diffract to much lower resolutions than protein crystals. This low-resolution diffraction results in unclear density maps, which cause considerable difficulties during the model-building process. These difficulties are exacerbated by the lack of computational tools for RNA modeling. Here, RCrane, a tool for the partially automated building of RNA into electron-density maps of low or intermediate resolution, is presented. This tool works within Coot, a common program for macromolecular model building. RCrane helps crystallographers to place phosphates and bases into electron density and then automatically predicts and builds the detailed all-atom structure of the traced nucleotides. RCrane then allows the crystallographer to review the newly built structure and select alternative backbone conformations where desired. This tool can also be used to automatically correct the backbone structure of previously built nucleotides. These automated corrections can fix incorrect sugar puckers, steric clashes and other structural problems. PMID:22868764

Keating, Kevin S; Pyle, Anna Marie



Atomistic modeling of dislocation-interface interactions  

SciTech Connect

Using atomic scale models and interface defect theory, we first classify interface structures into a few types with respect to geometrical factors, then study the interfacial shear response and further simulate the dislocation-interface interactions using molecular dynamics. The results show that the atomic scale structural characteristics of both heterophases and homophases interfaces play a crucial role in (i) their mechanical responses and (ii) the ability of incoming lattice dislocations to transmit across them.

Wang, Jian [Los Alamos National Laboratory; Valone, Steven M [Los Alamos National Laboratory; Beyerlein, Irene J [Los Alamos National Laboratory; Misra, Amit [Los Alamos National Laboratory; Germann, T. C. [Los Alamos National Laboratory



Model study of protein unfolding by interfaces  

NASA Astrophysics Data System (ADS)

We study interface-induced protein unfolding on hydrophobic and polar interfaces by means of a two-dimensional lattice model and an exhaustive enumeration ground-state structure search, for a set of model proteins of length 20 residues. We compare the effects of the two types of interfaces, and search for criteria that influence the retention of a protein’s native-state structure upon adsorption. We find that the unfolding proceeds by a large, sudden loss of native contacts. The unfolding at polar interfaces exhibits similar behavior to that at hydrophobic interfaces but with a much weaker interface coupling strength. Further, we find that the resistance of proteins to unfolding in our model is positively correlated with the magnitude of the folding energy in the native-state structure, the thermal stability (or energy gap) for that structure, and the interface energy for native-state adsorption. We find these factors to be of roughly equal importance.

Chakarova, S. D.; Carlsson, A. E.



Development of a commercial Automated Laser Gas Interface (ALGI) for AMS  

NASA Astrophysics Data System (ADS)

National Electrostatics Corporation (NEC), Massachusetts Institute of Technology (MIT), and GlaxoSmithKline (GSK) collectively have been developing an interface to introduce CO2 produced by the laser combustion of liquid chromatograph eluate deposited on a CuO substrate directly into the ion source of an AMS system, thereby bypassing the customary graphitization process. The Automated Laser Gas Interface (ALGI) converts dried liquid samples to CO2 gas quickly and efficiently, allowing 96 samples to be measured in as little as 16 h. 14C:12C ratios stabilize typically within 2 min of analysis time per sample. Presented is the recent progress of NEC's ALGI, a stand-alone accessory to an NEC gas-enabled multi-cathode source of negative ions by Cs sputtering (MC-SNICS) ion source.

Daniel, R.; Mores, M.; Kitchen, R.; Sundquist, M.; Hauser, T.; Stodola, M.; Tannenbaum, S.; Skipper, P.; Liberman, R.; Young, G.; Corless, S.; Tucker, M.



Modeling interface fracture in flip chip assembly  

Microsoft Academic Search

A flip chip assembly with underfill delamination subjected to thermal cycling loading was investigated using the finite element method and interface fracture mechanics. Numerical evaluation of the mixed mode stress intensity factors and mode mixing parameter for interface cracks located at the silicon\\/underfill and silicon\\/FR4 interfaces was carried out. Four types of delamination conditions in flip chip assembly were modeled.

H. L. J. Pang; X. R. Zhangl; X. Q. Shi; Z. P. Wang



Systems engineering interfaces: A model based approach  

NASA Astrophysics Data System (ADS)

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

Fosse, E.; Delp, C. L.


User Modeling in Adaptive Interfaces  

Microsoft Academic Search

In this paper we examine the notion of adaptive user interfaces, interactive sys- tems that invoke machine learning to improve their interaction with humans. We review some previous work in this emerging area, ranging from software that filters information to systems that support more complex tasks like scheduling. After this, we describe three ongoing research efforts that extend this framework

Pat Langley



Geometric Modeling Applications Interface Program.  

National Technical Information Service (NTIS)

This User Manual provides a description of the data exchange software developed under the Air Force sponsored Product Definition Data Interface contract (F33615-82-C5036) and is applicable to the GMAP contract (F33615-85-C-5122), which is sponsored by the...

C. V. Wie D. Emmerson R. Helldoerfer



Individual user interfaces and model-based user interface software tools  

Microsoft Academic Search

Currently, most of model-based user interface software tools use task, application, and presentation models to generate the running user interface. The point of this paper is to use an additional user model to create individual user interfaces. For it, individual user interfaces and model-based tools are analyzed briefly to define the starting point for this research work. The viability of

Egbert Schlungbaum



Parallel computing for automated model calibration  

SciTech Connect

Natural resources model calibration is a significant burden on computing and staff resources in modeling efforts. Most assessments must consider multiple calibration objectives (for example magnitude and timing of stream flow peak). An automated calibration process that allows real time updating of data/models, allowing scientists to focus effort on improving models is needed. We are in the process of building a fully featured multi objective calibration tool capable of processing multiple models cheaply and efficiently using null cycle computing. Our parallel processing and calibration software routines have been generically, but our focus has been on natural resources model calibration. So far, the natural resources models have been friendly to parallel calibration efforts in that they require no inter-process communication, only need a small amount of input data and only output a small amount of statistical information for each calibration run. A typical auto calibration run might involve running a model 10,000 times with a variety of input parameters and summary statistical output. In the past model calibration has been done against individual models for each data set. The individual model runs are relatively fast, ranging from seconds to minutes. The process was run on a single computer using a simple iterative process. We have completed two Auto Calibration prototypes and are currently designing a more feature rich tool. Our prototypes have focused on running the calibration in a distributed computing cross platform environment. They allow incorporation of?smart? calibration parameter generation (using artificial intelligence processing techniques). Null cycle computing similar to SETI@Home has also been a focus of our efforts. This paper details the design of the latest prototype and discusses our plans for the next revision of the software.

Burke, John S.; Danielson, Gary R.; Schulz, Douglas A.; Vail, Lance W.




Microsoft Academic Search

This paper describes the results obtained in the final performing period of the ARPA sponsored submarine automation project1. Efforts on the mapping between the submarine operational environment and the RCS software architecture lead to the result of three watch station graphic user interface panels. The submarine automation model has been expanded to include some engineering systems control capability. On the

Hui-Min Huang; Richard Quintero


A Technology Adaptation Model for Business Process Automation  

Microsoft Academic Search

A number of new technologies aimed at automating office work has been developed over the last 20 years with seemingly little impact on overall office productivity. We propose a conceptual model for technology adaptation for business process automation that stresses both technology-organization fit and technology- process fit. The goal of our study is to develop a systematic approach that addresses

Edward A. Stohr; J. Leon Zhao



Generating user interface code in a model based user interface development environment  

Microsoft Academic Search

Declarative models play an important role in most software design activities, by allowing designs to be constructed that selectively abstract over complex implementation details. In the user interface setting, Model-Based User Interface Development Environments (MB-UIDEs) provide a context within which declarative models can be constructed and related, as part of the interface design process. However, such declarative models are not

Paulo Pinheiro da Silva; Tony Griffiths; Norman W. Paton



Interfacing a robotic station with a gas chromatograph for the full automation of the determination of organochlorine pesticides in vegetables  

SciTech Connect

A fully automated method for the determination of organochlorine pesticides in vegetables is proposed. The overall system acts as an {open_quotes}analytical black box{close_quotes} because a robotic station performs the prelimninary operations, from weighing to capping the leached analytes and location in an autosampler of an automated gas chromatograph with electron capture detection. The method has been applied to the determination of lindane, heptachlor, captan, chlordane and metoxcychlor in tea, marjoram, cinnamon, pennyroyal, and mint with good results in most cases. A gas chromatograph has been interfaced to a robotic station for the determination of pesticides in vegetables. 15 refs., 4 figs., 2 tabs.

Torres, P.; Luque de Castro, M.D. [Univ. of Cordoba (Spain)



Statistical modeling of shock-interface interaction  

NASA Astrophysics Data System (ADS)

Direct simulations of shock-induced mixing of corrugated air-helium interfaces have been performed using EAD, a 2D Eulerian code with a mixed-cell treatment. The total amount of fluctuating kinetic energy produced before the shock (M = 1.2-1.3 in air) leaves the interface can be expressed as a function of interface variance (rms amplitude) and is in qualitative agreement with a theoretical estimate. By reducing the 2D results into 1D profiles, we have also been able to favorably compare the mixing rates and intensities computed by EAD and those predicted by a turbulence transport model with some of its closures based on two-field expressions. The results of this study supply reasonable values for initialization of fully developed turbulence models, such as k - ? and its extensions, for problems involving shock-induced interfacial mixing.

Besnard, D. C.; Haas, J. F.; Rauenzahn, R. M.



Gesture Interface: Modeling and Learning  

Microsoft Academic Search

This paper presents a method for developing a gesture-based system using a multidimensional hidden Markov model (HMM). Instead of using geometric features, gestures are converted into sequential symbols. HMMs are employed to represent the gestures and their parameters are learned from the training data. Based on “the most likely performance” criterion, the gestures can be recognized by evaluating the trained

Jie Yang; Yangsheng Xu; C. S. Chen



Automated Procedure for Material Parameter Evaluation for Viscoplastic Constitutive Models.  

National Technical Information Service (NTIS)

An automated procedure is presented for evaluating the material parameters in Walker's exponential viscoplastic constitutive model for metals at elevated temperature. Both physical and numerical approximations are utilized to compute the constants for Inc...

P. K. Imbrie G. H. James P. S. Hill D. H. Allen W. E. Haisler



A permeation model for the electrochemical interface  

NASA Astrophysics Data System (ADS)

We show the transferability of the recently introduced concept of permeation from the context of finite dissipation in simple metallic interfaces to much more complicated electrochemical interfaces. The phenomenological bridge is formed by the exchange current, which can be measured by either impedance spectroscopy or by cyclic voltammetry. In a proof-of-concept phase field model, Nernst–Planck diffusion and transport of charged species in a potential gradient as the solution of the Poisson equation are considered. It is shown that charges build up on the outer electrode surface in a fashion resembling the electrochemical double layer.

Preiss, U.; Borukhovich, E.; Alemayehu, N.; Steinbach, I.; LaMantia, F.



Models and methodology in support of automated data base reorganization  

Microsoft Academic Search

This research defines an analytic model to be used in the study of automated reorganization. Details of the development of the model are presented and the results of the experiments conducted with the model are discussed. The model is evaluated in terms of its usefulness in data base performance studies, its generalizability to environments other than the one modeled, and



Designing for Flexible Interaction Between Humans and Automation: Delegation Interfaces for Supervisory Control  

Microsoft Academic Search

Objective: To develop a method enabling human-like, flexible supervisory control via delegation to automation. Background: Real-time supervisory relationships with automation are rarely as flexible as human task delegation to other humans. Flexibility in human-adaptable automation can provide important benefits, includ- ing improved situation awareness, more accurate automation usage, more balanced mental workload, increased user acceptance, and improved overall performance. Method:

Christopher A. Miller; Raja Parasuraman



Ultrasonic scattering from imperfect interfaces: A quasi-static model  

Microsoft Academic Search

A quasi-static model for the ultrasonic transmission and reflection at imperfect interfaces is developed. The interface is represented by a distributed spring, determined by the change in static compliance of the medium with respect to one with a perfect interface, and a distributed mass, representing excess mass at the interface. Comparison of the model predictions to exact solutions for two

Jai-Man Baik; R. Bruce Thompson



Three-dimensional, automated, real-time video system for tracking limb motion in brain–machine interface studies  

Microsoft Academic Search

Collection and analysis of limb kinematic data are essential components of the study of biological motion, including research into biomechanics, kinesiology, neurophysiology and brain–machine interfaces (BMIs). In particular, BMI research requires advanced, real-time systems capable of sampling limb kinematics with minimal contact to the subject's body. To answer this demand, we have developed an automated video tracking system for real-time

Ian D. Peikon; Nathan A. Fitzsimmons; Mikhail A. Lebedev; Miguel A. L. Nicolelis



Automation Marketplace 2010: New Models, Core Systems  

ERIC Educational Resources Information Center

|In a year when a difficult economy presented fewer opportunities for immediate gains, the major industry players have defined their business strategies with fundamentally different concepts of library automation. This is no longer an industry where companies compete on the basis of the best or the most features in similar products but one where…

Breeding, Marshall



Automation Marketplace 2010: New Models, Core Systems  

ERIC Educational Resources Information Center

In a year when a difficult economy presented fewer opportunities for immediate gains, the major industry players have defined their business strategies with fundamentally different concepts of library automation. This is no longer an industry where companies compete on the basis of the best or the most features in similar products but one where…

Breeding, Marshall



Variational Implicit Solvation with Solute Molecular Mechanics: From Diffuse-Interface to Sharp-Interface Models  

PubMed Central

Central in a variational implicit-solvent description of biomolecular solvation is an effective free-energy functional of the solute atomic positions and the solute-solvent interface (i.e., the dielectric boundary). The free-energy functional couples together the solute molecular mechanical interaction energy, the solute-solvent interfacial energy, the solute-solvent van der Waals interaction energy, and the electrostatic energy. In recent years, the sharp-interface version of the variational implicit-solvent model has been developed and used for numerical computations of molecular solvation. In this work, we propose a diffuse-interface version of the variational implicit-solvent model with solute molecular mechanics. We also analyze both the sharp-interface and diffuse-interface models. We prove the existence of free-energy minimizers and obtain their bounds. We also prove the convergence of the diffuse-interface model to the sharp-interface model in the sense of ?-convergence. We further discuss properties of sharp-interface free-energy minimizers, the boundary conditions and the coupling of the Poisson–Boltzmann equation in the diffuse-interface model, and the convergence of forces from diffuse-interface to sharp-interface descriptions. Our analysis relies on the previous works on the problem of minimizing surface areas and on our observations on the coupling between solute molecular mechanical interactions with the continuum solvent. Our studies justify rigorously the self consistency of the proposed diffuse-interface variational models of implicit solvation.

Li, Bo; Zhao, Yanxiang



Model-based automated reconfiguration for fault isolation and restoration  

Microsoft Academic Search

This paper presents a new concept for automated reconfiguration control that is based on past model-based system analysis, load modeling and integrated system recovery analysis research and development. The approach uses a software based supervisory level control application that: (1) Monitors device level distribution protection device operation, (2) Generates isolation refinement and restoration switch operation lists using a model-based reconfiguration

K. J. Russell; R. P. Broadwater



Interfacing materials models with fire field models  

Microsoft Academic Search

For flame spread over solid materials, there has traditionally been a large technology gap between fundamental combustion research and the somewhat simplistic approaches used for practical, real-world applications. Recent advances in computational hardware and computational fluid dynamics (CFD)-based software have led to the development of fire field models. These models, when used in conjunction with material burning models, have the

V. F. Nicolette; S. R. Tieszen; J. L. Moya



Automated quantitative gait analysis in animal models of movement disorders  

Microsoft Academic Search

BACKGROUND: Accurate and reproducible behavioral tests in animal models are of major importance in the development and evaluation of new therapies for central nervous system disease. In this study we investigated for the first time gait parameters of rat models for Parkinson's disease (PD), Huntington's disease (HD) and stroke using the Catwalk method, a novel automated gait analysis test. Static

Caroline Vandeputte; Jean-Marc Taymans; Cindy Casteels; Frea Coun; Yicheng Ni; Koen Van Laere; Veerle Baekelandt



Automated Port Pricing Model. Volume 2. User's Manual.  

National Technical Information Service (NTIS)

Volume II of the two-volume report contains step-by-step instructions, specifically developed to accompany the computer software (diskettes), used to complete the automated version of the pricing model. The overall purpose of the model is to derive cost c...



Parmodel: a web server for automated comparative modeling of proteins.  


Parmodel is a web server for automated comparative modeling and evaluation of protein structures. The aim of this tool is to help inexperienced users to perform modeling, assessment, visualization, and optimization of protein models as well as crystallographers to evaluate structures solved experimentally. It is subdivided in four modules: Parmodel Modeling, Parmodel Assessment, Parmodel Visualization, and Parmodel Optimization. The main module is the Parmodel Modeling that allows the building of several models for a same protein in a reduced time, through the distribution of modeling processes on a Beowulf cluster. Parmodel automates and integrates the main softwares used in comparative modeling as MODELLER, Whatcheck, Procheck, Raster3D, Molscript, and Gromacs. This web server is freely accessible at . PMID:15555595

Uchôa, Hugo Brandão; Jorge, Guilherme Eberhart; Freitas Da Silveira, Nelson José; Camera, João Carlos; Canduri, Fernanda; De Azevedo, Walter Filgueira



Design and implementation of a user-friendly interface for DIII-D neutral beam automated operation  

SciTech Connect

The operational interface to the DIII-D neutral beam system, in use for the past 10 years, consisted of several interactive devices that the operator used to sequence neutral beam conditioning and plasma heating shots. Each of four independent MODCOMP Classic control computers (for four DIII-D beamlines) included a touch screen, rotary knobs, an interactive dual port terminal, and a keyboard to selectively address each of five display screens. Most of the hardware had become obsolete and repair was becoming increasingly expensive. It was clear that the hardware could be replaced with current equipment, while improving the ergonomics of control. Combined with an ongoing effort to increase the degree of automated operation and its reliability, a single microcomputer-based interface for each of the four neutral beam MODCOMP Classic control computers was developed, effectively replacing some twenty pieces of hardware. Macintosh II microcomputers were selected, with 1 megabyte of RAM and off-the-shelf'' input/output (I/O) consisting of a mouse, serial ports, and two monochrome high-resolution video monitors. The software is written in PASCAL and adopts standard Macintosh window'' techniques. From the Macintosh interface to the MODCOMP Classic, the operator can control the power supply setpoints, adjust ion source timing and synchronization, call up waveform displays on the Grinnell color display system, view the sequencing of procedures to ready a neutral beam shot, and add operator comments to an automated shot logging system. 3 refs., 2 figs.

Phillips, J.; Colleraine, A.P.; Hong, R.; Kim, J.; Lee, R.L.; Wight, J.J.



Modelling mechanical interfaces experiencing micro-slip\\/slap  

Microsoft Academic Search

Surface-to-surface contact interfaces significantly affect structural behaviour. Therefore, accurate modelling of the stiffness and damping characteristics of such interfaces is crucial for dynamic response analysis of assembled structures. Due to the development of nonlinear interactions, such as slip and slap mechanisms, modelling and analysis of the contact interfaces is a challenging task. The nonlinear effects of the slip and slap

H. Jalali; A. Hedayati; H. Ahmadian



A model for types and levels of human interaction with automation  

Microsoft Academic Search

We outline a model for types and levels of automation that provides a framework and an objective basis for deciding which system functions should be automated and to what extent. Appropriate selection is important because automation does not merely supplant but changes human activity and can impose new coordination demands on the human operator. We propose that automation can be

Raja Parasuraman; Thomas B. Sheridan; Christopher D. Wickens




EPA Science Inventory

The Automated Geospatial Watershed Assessment tool (AGWA) is a GIS interface jointly developed by the USDA Agricultural Research Service, the U.S. Environmental Protection Agency, the University of Arizona, and the University of Wyoming to automate the parame...


Interactive Assessment of User Preference Models: The Automated Travel Assistant  

Microsoft Academic Search

This paper presents the candidate\\/critique model of interactive problem solv - ing, in which an automated problem solver communicates candidate solutions to the user and the user critiques those solutions. The system starts with minimal in formation about the user's preferences, and preferences are elicite d and inferred incrementally by analyz- ing the critiques. The system's goal is to present

Greg Linden; Steve Hanks; Neal Lesh


Automating Nurse Self-Rostering: A Multiagent Systems Model  

Microsoft Academic Search

This paper presents a multiagent systems model for constructing nurse rosters. Over the past decade self-rostering has become more favorable in nursing personnel scheduling, due to its empowerment and motivational benefits. However, the labor intensive negotiation procedure among participants has limited its application to medium sized and large wards. To overcome this limitation, we propose an automated negotiation tool utilizing

Zhiguo Wang; Chun Wang



Task automation for modelling solids with Catia V5  

Microsoft Academic Search

Purpose – The main goal of this paper is to show how the automation of tasks in solid modelling with Catia V5 is approached, by means of macros, working under the Windows operating system and with the Visual BASIC programming language. A macro is a piece of code (written in a certain programming language) which groups a set of operations

María Gloria Del Río-Cidoncha; Juan Martínez-Palacios; Francisco Ortuño-Ortiz



Microcomputer-Based Local Automation Model: Test Plan.  

National Technical Information Service (NTIS)

This Test Plan for the microcomputer-based Local Automation Model (microLAM) is written to: 1) Establish a comprehensive test plan to determine whether the prototype system provides the functions and capabilities required for the microLAM; 2) Describe the...

R. W. Hartt D. J. O'Connor



On automation of the procedure for crystal structure model refinement  

NASA Astrophysics Data System (ADS)

The methods of automation of the procedure for crystal structure model refinement from experimental diffraction data, implemented in the ASTRA program package, are described. Such tools as statistical tests, parameter scanning, and data scanning reduce the time necessary for structural investigation. At strong correlations between parameters, especially when the data set is limited, parameter scanning has an advantage over the full-matrix refinement.

Dudka, A. P.



User-centered modeling and evaluation of multimodal interfaces  

Microsoft Academic Search

Historically, the development of computer interfaces has been a technology-driven phenomenon. However, new multimodal interfaces are composed of recognition-based technologies that must interpret human speech, gesture, gaze, movement patterns, and other complex natural behaviors, which involve highly automatized skills that are not under full conscious control. As a result, it now is widely acknowledged that multimodal interface design requires modeling




Improved Interfacing of Electrical Machine Models to Electromagnetic Transients Programs  

Microsoft Academic Search

A new technique is presented for interfacing electrical machine models with electromagnetic transients programs. The machine models with their associated controls, loads or turbines can be assembled as subroutines by the user and interfaced to the electrical network or other machine models directly. The machine models employ the standard state variable equations and may use any integration technique for solution.

A. M. Gole; R. W. Menzies; H. M. Turanli; D. A. Woodford



Automated Negotiation through a Cooperative-Competitive Model  

Microsoft Academic Search

\\u000a Automated negotiation has become increasingly important and pervasive since the advent of e-Business. It frees people from\\u000a tedious interactions, improves the efficiency of e-business and ensures the accuracy of complex service composition. However,\\u000a there are limitations of the existing negotiation models. Firstly, the majority of existing negotiation models are ”price”\\u000a bargain type of negotiation. It does not consider the reasons

Xuehong Tao; Zhiqi Shen; Chunyan Miao; Yin-Leng Theng; Yuan Miao; Han Yu


Automated security hardening for evolving UML models  

Microsoft Academic Search

Developing security-critical software correctly and securely is dicult. To address this problem, there has been a significant amount of work over the last 10 years on providing model-based development approaches based on the Unified Modeling Language which aim to raise the trustworthiness of security-critical systems, some of them including tools allowing the user to check whether a UML model satisfies

Jan Jürjens



The Automated Digital Network System (ADNS) Interface to Transformational Satellite Communications System (TSAT)  

Microsoft Academic Search

The U. S. Department of Defense (DoD) is in the initial phase of building the Global Information Grid (GIG), a private secure internetwork connecting a number of its joint and service-specific IP networks. Two of these networks are the Automated Digital Network System (ADNS) and the Transformational Satellite Communications System (TSAT). ADNS provides network services and entry into the Defense

Joanna N. Ptasinski; Yenchi Congtang



Facilitating the exploration of interface design alternatives: the HUMANOID model of interface design  

Microsoft Academic Search

HUMANOID is a user interface design tool that lets designers express abstract conceptualizations of an interface in an executable form, allowing designers to experiment with scenarios and dialogues even before the application model is completely worked out. Three properties of the HUMANOID approach allow it to do so: a modularization of design issues into independent dimensions, support for multiple levels

Pedro A. Szekely; Ping Luo; Robert Neches



Beyond Hacking: a Model Based Approach to User Interface Design  

Microsoft Academic Search

This paper discusses the role of models in the design of user interfaces, with particular emphasis on integration across different modelling stages. We are concerned with bridging the gap between psychologically motivated mod- elling approaches to HCI and implementation oriented interaction models, to produce a task-informed user interface design process. An early version of a UIDE which provides support for

S. Wilson; P. Johnson; C. Kelly; J. Cunningham; P. Markopoulos



Hexapods with fieldbus interfaces for automated manufacturing of opto-mechanical components  

NASA Astrophysics Data System (ADS)

The adjustment of opto-mechanical components in manufacturing processes often requires precise motion in all six degrees of freedom with nanometer range resolution and absence of hysteresis. Parallel kinematic systems are predestined for such tasks due to their compact design, low inertia and high stiffness resulting in rapid settling behavior. To achieve adequate system performance, specialized motion controllers are required to handle the complex kinematic models for the different types of Hexapods and the associated extensive calculations of inverse kinematics. These controllers often rely on proprietary command languages, a fact that demands a high level of familiarization. This paper describes how the integration of fieldbus interfaces into Hexapod controllers simplifies the communication while providing higher flexibility. By using standardized communication protocols with cycle times down to 12.5 ?s it is straightforward to control multiple Hexapods and other devices by superordinate PLCs of different manufacturers. The paper also illustrates how to simplify adjustment and alignment processes by combining scanning algorithms with user defined coordinate systems.

Schreiber, Steffen; Muellerleile, Christian; Frietsch, Markus; Gloess, Rainer



Automated Environment Generation for Software Model Checking  

Microsoft Academic Search

A key problem in model checking open systems is en- vironment modeling (i.e., representing the behavior of the execution context of the system under analysis). Software systems are fundamentally open since their behavior is de- pendent on patterns of invocation of system components and values defined outside the system but referenced within the system. Whether reasoning about the behavior of

Oksana Tkachuk; Matthew B. Dwyer; Corina S. Pasareanu



Models for Automated Tube Performance Calculations  

SciTech Connect

High power radio-frequency systems, as typically used in fusion research devices, utilize vacuum tubes. Evaluation of vacuum tube performance involves data taken from tube operating curves. The acquisition of data from such graphical sources is a tedious process. A simple modeling method is presented that will provide values of tube currents for a given set of element voltages. These models may be used as subroutines in iterative solutions of amplifier operating conditions for a specific loading impedance.

C. Brunkhorst



Automated variable selection methods for logistic regression produced unstable models for predicting acute myocardial infarction mortality  

Microsoft Academic Search

ObjectivesAutomated variable selection methods are frequently used to determine the independent predictors of an outcome. The objective of this study was to determine the reproducibility of logistic regression models developed using automated variable selection methods.

Peter C. Austin; Jack V. Tu



Automated Detection of Influenza Epidemics with Hidden Markov Models  

Microsoft Academic Search

We present a method for automated detection of influenza epidemics. The method uses Hidden Markov Models with an Exponential-Gaussian mix- ture to characterize the non-epidemic and epidemic dynamics in a time series of influenza-like illness incidence rates. Our evaluation on real data shows a re- duction in the number of false detections compared to previous approaches and increased robustness to

Toni M. Rath; Maximo Carreras; Paola Sebastiani



Travel-Time Models for Automated Storage\\/Retrieval Systems  

Microsoft Academic Search

Travel-time models are developed for automated storage\\/retrieval (AS\\/R) machines. The S\\/R machine travels simultaneously horizontally and vertically as it moves along a storage aisle. For randomized storage conditions expected travel times are determined for both single and dual command cycles. Alternative input\\/output (I\\/O) locations are considered. Additionally, various dwell-point strategies for the storage\\/retrieval machine are examined.

Yavuz A. Bozer; John A. White



Automated refinement and inference of analytical models for metabolic networks.  


The reverse engineering of metabolic networks from experimental data is traditionally a labor-intensive task requiring a priori systems knowledge. Using a proven model as a test system, we demonstrate an automated method to simplify this process by modifying an existing or related model--suggesting nonlinear terms and structural modifications--or even constructing a new model that agrees with the system's time series observations. In certain cases, this method can identify the full dynamical model from scratch without prior knowledge or structural assumptions. The algorithm selects between multiple candidate models by designing experiments to make their predictions disagree. We performed computational experiments to analyze a nonlinear seven-dimensional model of yeast glycolytic oscillations. This approach corrected mistakes reliably in both approximated and overspecified models. The method performed well to high levels of noise for most states, could identify the correct model de novo, and make better predictions than ordinary parametric regression and neural network models. We identified an invariant quantity in the model, which accurately derived kinetics and the numerical sensitivity coefficients of the system. Finally, we compared the system to dynamic flux estimation and discussed the scaling and application of this methodology to automated experiment design and control in biological systems in real time. PMID:21832805

Schmidt, Michael D; Vallabhajosyula, Ravishankar R; Jenkins, Jerry W; Hood, Jonathan E; Soni, Abhishek S; Wikswo, John P; Lipson, Hod



Automated refinement and inference of analytical models for metabolic networks  

NASA Astrophysics Data System (ADS)

The reverse engineering of metabolic networks from experimental data is traditionally a labor-intensive task requiring a priori systems knowledge. Using a proven model as a test system, we demonstrate an automated method to simplify this process by modifying an existing or related model--suggesting nonlinear terms and structural modifications--or even constructing a new model that agrees with the system's time series observations. In certain cases, this method can identify the full dynamical model from scratch without prior knowledge or structural assumptions. The algorithm selects between multiple candidate models by designing experiments to make their predictions disagree. We performed computational experiments to analyze a nonlinear seven-dimensional model of yeast glycolytic oscillations. This approach corrected mistakes reliably in both approximated and overspecified models. The method performed well to high levels of noise for most states, could identify the correct model de novo, and make better predictions than ordinary parametric regression and neural network models. We identified an invariant quantity in the model, which accurately derived kinetics and the numerical sensitivity coefficients of the system. Finally, we compared the system to dynamic flux estimation and discussed the scaling and application of this methodology to automated experiment design and control in biological systems in real time.

Schmidt, Michael D.; Vallabhajosyula, Ravishankar R.; Jenkins, Jerry W.; Hood, Jonathan E.; Soni, Abhishek S.; Wikswo, John P.; Lipson, Hod



Grcarma: A fully automated task-oriented interface for the analysis of molecular dynamics trajectories.  


We report the availability of grcarma, a program encoding for a fully automated set of tasks aiming to simplify the analysis of molecular dynamics trajectories of biological macromolecules. It is a cross-platform, Perl/Tk-based front-end to the program carma and is designed to facilitate the needs of the novice as well as those of the expert user, while at the same time maintaining a user-friendly and intuitive design. Particular emphasis was given to the automation of several tedious tasks, such as extraction of clusters of structures based on dihedral and Cartesian principal component analysis, secondary structure analysis, calculation and display of root-meansquare deviation (RMSD) matrices, calculation of entropy, calculation and analysis of variance–covariance matrices, calculation of the fraction of native contacts, etc. The program is free-open source software available immediately for download. PMID:24159629

Koukos, Panagiotis I; Glykos, Nicholas M



Generating user interfaces from data models and dialogue net specifications  

Microsoft Academic Search

A method and a set of supporting tools have been developed for an improved integration of user interface design with software engineering methods and tools. Animated user interfaces for database-oriented applications are generated from an extended data model and a new graphical technique for specifying dialogues. Based on views defined for the data model, an expert system uses explicit design

Christian Janssen; Anette Weisbecker; Jürgen Ziegler



Automated photogrammetry for three-dimensional models of urban spaces  

NASA Astrophysics Data System (ADS)

The location-aware Internet is inspiring intensive work addressing the automated assembly of three-dimensional models of urban spaces with their buildings, circulation spaces, vegetation, signs, even their above-ground and underground utility lines. Two-dimensional geographic information systems (GISs) and municipal utility information exist and can serve to guide the creation of models being built with aerial, sometimes satellite imagery, streetside images, indoor imaging, and alternatively with light detection and ranging systems (LiDARs) carried on airplanes, cars, or mounted on tripods. We review the results of current research to automate the information extraction from sensor data. We show that aerial photography at ground sampling distances (GSD) of 1 to 10 cm is well suited to provide geometry data about building facades and roofs, that streetside imagery at 0.5 to 2 cm is particularly interesting when it is collected within community photo collections (CPCs) by the general public, and that the transition to digital imaging has opened the no-cost option of highly overlapping images in support of a more complete and thus more economical automation. LiDAR-systems are a widely used source of three-dimensional data, but they deliver information not really superior to digital photography.

Leberl, Franz; Meixner, Philipp; Wendel, Andreas; Irschara, Arnold



Diffuse-interface field approach to modeling arbitrarily-shaped particles at fluid-fluid interfaces.  


We present a novel mesoscale simulation approach to modeling the evolution of solid particles segregated at fluid-fluid interfaces. The approach involves a diffuse-interface field description of each fluid phase in addition to the set of solid particles. The unique strength of the model is its generality to include particles of arbitrary shapes and orientations, as well as the ability to incorporate electrostatic particle interactions and external forces via a previous work [P.C. Millett, Y.U. Wang, Acta Mater. 57 (2009) 3101]. In this work, we verify that the model produces the correct capillary forces and contact angles by comparing with a well-defined analytical solution. In addition, simulation results of rotations of various-shaped particles at fluid-fluid interfaces, external force-induced capillary attraction/repulsion between particles, and spinodal decomposition arrest due to colloidal particle jamming at the interfaces are presented. PMID:20888570

Millett, Paul C; Wang, Yu U



A Automated Off-Line Liquid Chromatography\\/mass Spectrometry Interface Using Solid Phase, Time-Of Secondary Ion Mass Spectrometry  

Microsoft Academic Search

The design and construction of an automated off -line interface to couple a microbore HPLC to the Manitoba TOF I SIMS is described. In particular, the details of adapting the electrospray sample deposition method to deposit the eluent of a microbore HPLC column are discussed. Several improvements to the electrospray method were made to improve sensitivity. The spray was focussed

Ronald Charles Beavis



glmulti: An R Package for Easy Automated Model Selection with (Generalized) Linear Models  

Microsoft Academic Search

We introduce glmulti, an R package for automated model selection and multi-model inference with glm and related functions. From a list of explanatory variables, the provided function glmulti builds all possible unique models involving these variables and, optionally, their pairwise interactions. Restrictions can be specified for candidate models, by excluding specific terms, enforcing marginality, or controlling model complexity. Models are

Vincent Calcagno; Claire de Mazancourt



Diffuse-interface model for smoothed particle hydrodynamics.  


Diffuse-interface theory provides a foundation for the modeling and simulation of microstructure evolution in a very wide range of materials, and for the tracking and capturing of dynamic interfaces between different materials on larger scales. Smoothed particle hydrodynamics (SPH) is also widely used to simulate fluids and solids that are subjected to large deformations and have complex dynamic boundaries and/or interfaces, but no explicit interface tracking or capturing is required, even when topological changes such as fragmentation and coalescence occur, because of its Lagrangian particle nature. Here we developed a SPH model for single-component two-phase fluids that is based on diffuse-interface theory. In the model, the interface has a finite thickness and a surface tension that depend on the coefficient k of the gradient contribution to the Helmholtz free energy functional and the density-dependent homogeneous free energy. In this model, there is no need to locate the surface (or interface) or to compute the curvature at and near the interface. One- and two-dimensional SPH simulations were used to validate the model. PMID:19392076

Xu, Zhijie; Meakin, Paul; Tartakovsky, Alexandre M



Programmable user models for predictive evaluation of interface designs  

Microsoft Academic Search

A Programmable User Model (PUM) is a psychologically constrained architecture which an interface designer is invited to program to simulate a user performing a range of tasks with a proposed interface. It provides a novel way of conveying psychological considerations to the designer, by involving the designer in the process of making predictions of usability. Development of the idea leads

Richard M. Young; T. R. G. Green; Tony Simon



A model for the origin of solar wind stream interfaces  

Microsoft Academic Search

The basic variations in solar wind properties that have been observed at 'stream interfaces' near 1 AU are explained by a gas dynamic model in which a radially propagating stream, produced by a temperature variation in the solar envelope, steepens nonlinearly while moving through interplanetary space. The region thus identified with the stream interface separates the ambient solar wind from

A. J. Hundhausen; L. F. Burlaga



Friction Modeling and Compensation for Haptic Interfaces  

Microsoft Academic Search

Friction cancellation and high gain force feedback are studied for their relative beneìts in mitigating the effects of friction in haptic interfaces. Although either technique alone is capable of signiìcant improvements, we ìnd that a combination of approximate cancellation coupled with variable-gain low-bandwidth force feedback provides ex- cellent friction reduction and is more robust. This improves the feel of the

Nicholas L. Bernstein; Dale A. Lawrence; Lucy Y. Pao



Study of the Interface Electronic Structure of a Model Metal-Semiconductor Interface,  

National Technical Information Service (NTIS)

A study is presented of the interface electronic structure of a model simple-cubic metal and a compound semiconductor of the cesium-chloride structure. Both the metal and the semiconductor are described in terms of nearest-neighbor tight-binding models wh...

D. N. Lowy A. Madhukar



Automated Physico-Chemical Cell Model Development through Information Theory  

SciTech Connect

The objective of this project was to develop predictive models of the chemical responses of microbial cells to variations in their surroundings. The application of these models is optimization of environmental remediation and energy-producing biotechnical processes.The principles on which our project is based are as follows: chemical thermodynamics and kinetics; automation of calibration through information theory; integration of multiplex data (e.g. cDNA microarrays, NMR, proteomics), cell modeling, and bifurcation theory to overcome cellular complexity; and the use of multiplex data and information theory to calibrate and run an incomplete model. In this report we review four papers summarizing key findings and a web-enabled, multiple module workflow we have implemented that consists of a set of interoperable systems biology computational modules.

Peter J. Ortoleva



Task Models in the Context of User Interface Development  

NASA Astrophysics Data System (ADS)

Task models are widely used in the field of user interface development. They represent a human actor's performance or the co-operation of a group of people on or together with a system. For considerable time, it was an open problem in the field how to switch from the analyzing step of task analysis and modeling to the synthesizing step of user interface design. In the meantime, interesting approaches have shown up dealing with this problem and helping to bridge the gap between task modeling and user interface development. In this chapter, some of these approaches are discussed, together with recent concepts used to improve the usability of user interfaces based upon underlying task models.

Szwillus, Gerd


Geometric Modeling Applications Interface Program. Schema Manager User's Manual.  

National Technical Information Service (NTIS)

This User Manual provides a Schema Manager software guide developed under the Computer Integrated Manufacturing program known as GMAP (Geometric Modeling Applications Interface Program), U.S. Air Force Contract F33615-85-C-5122. It includes a description ...

C. Van Wie D. Emerson R. Helldoerfer



Models of defects at bi-material interfaces  

NASA Astrophysics Data System (ADS)

Multi-phase composite materials with a high density of bi-material interfaces can exhibit striking strength and robustness in extreme conditions such as shock and radiation damage. Laminar composites of Ag-Cu, Cu-Nb, and Ag-Fe with submicron to nano-scale layer thicknesses have recently been fabricated, but theoretical models of such systems are lacking. The plastic deformation behavior of nano-scale composites is dominated by defects, such as dislocations and twins, that are controlled by the interfaces. We investigate the phenomenology of defect dynamics at bi-material interfaces using Landau theory based models that span atomic and mesoscales.

Barros, Kipton; Lookman, Turab



A Discontinuous Elastic Interface Transfer Model of Thin Film Nanoindentation  

Microsoft Academic Search

A new model of thin film indentation that accounted for an apparent discontinuity in elastic strain transfer at the film\\/substrate\\u000a interface was developed. Finite element analysis suggested that numerical values of strain were not directly continuous across\\u000a the interface; the values in the film were higher when a soft film was deposited on a hard substrate. The new model was

B. Zhou; B. C. Prorok



QSAR workbench: automating QSAR modeling to drive compound design.  


We describe the QSAR Workbench, a system for the building and analysis of QSAR models. The system is built around the Pipeline Pilot workflow tool and provides access to a variety of model building algorithms for both continuous and categorical data. Traditionally models are built on a one by one basis and fully exploring the model space of algorithms and descriptor subsets is a time consuming basis. The QSAR Workbench provides a framework to allow for multiple models to be built over a number of modeling algorithms, descriptor combinations and data splits (training and test sets). Methods to analyze and compare models are provided, enabling the user to select the most appropriate model. The Workbench provides a consistent set of routines for data preparation and chemistry normalization that are also applied for predictions. The Workbench provides a large degree of automation with the ability to publish preconfigured model building workflows for a variety of problem domains, whilst providing experienced users full access to the underlying parameterization if required. Methods are provided to allow for publication of selected models as web services, thus providing integration with the chemistry desktop. We describe the design and implementation of the QSAR Workbench and demonstrate its utility through application to two public domain datasets. PMID:23615761

Cox, Richard; Green, Darren V S; Luscombe, Christopher N; Malcolm, Noj; Pickett, Stephen D



New model for the hydroxyapatite-octacalcium phosphate interface.  


Some experimental results have indicated that hydroxyapatite (HA) and octacalcium phosphate (OCP) can form an epitaxic interface. Subsequently the OCP-HA interface has become of great biological interest in the context of mineralized tissue formation. In this work a new OCP-HA interface model based on Brown's proposed configuration [Brown (1962), Nature, 197, 1048-1050] and using the minimum interface free-energy optimization is presented. This new model is formed by half a unit cell of HA and one unit cell of OCP, as in Brown's model, but in our case [1-210] of HA is 'glued' with [010] of OCP. Therefore, the relationship found was: [000-1](HA) parallel to [001](OCP) and [1-210](HA) parallel to [010](OCP). Self-consistent field methods were used for the analysis of Brown's model and ours. It is shown that the atoms in our model have similar environments as in the HA and OCP unit cells and that, as a result of the differences between HA and OCP unit-cell parameters, this interface presents misfit-dislocation-like features. High-resolution transmission electron microscopy (HREM) simulated images for the new interface model have been included and, when they are compared with the experimental ones, the similarity is quite good. PMID:12657811

Fernández, M E; Zorrilla-Cangas, C; García-García, R; Ascencio, J A; Reyes-Gasga, J



A generalized mechanical model for suture interfaces of arbitrary geometry  

NASA Astrophysics Data System (ADS)

Suture interfaces with a triangular wave form commonly found in nature have recently been shown to exhibit exceptional mechanical behavior, where geometric parameters such as amplitude, frequency, and hierarchy can be used to nonlinearly tailor and amplify mechanical properties. In this study, using the principle of complementary virtual work, we formulate a generalized, composite mechanical model for arbitrarily-shaped interdigitating suture interfaces in order to more broadly investigate the influence of wave-form geometry on load transmission, deformation mechanisms, anisotropy, and stiffness, strength, and toughness of the suture interface for tensile and shear loading conditions. The application of this suture interface model is exemplified for the case of the general trapezoidal wave-form. Expressions for the in-plane stiffness, strength and fracture toughness and failure mechanisms are derived as nonlinear functions of shape factor ? (which characterizes the general trapezoidal shape as triangular, trapezoidal, rectangular or anti-trapezoidal), the wavelength/amplitude ratio, the interface width/wavelength ratio, and the stiffness and strength ratios of the skeletal/interfacial phases. These results provide guidelines for choosing and tailoring interface geometry to optimize the mechanical performance in resisting different loads. The presented model provides insights into the relation between the mechanical function and the morphological diversity of suture interface geometries observed in natural systems.

Li, Yaning; Ortiz, Christine; Boyce, Mary C.



T:XML: A Tool Supporting User Interface Model Transformation  

NASA Astrophysics Data System (ADS)

Model driven development of user interfaces is based on the transformation of an abstract specification into the final user interface the user will interact with. The design of transformation rules to carry out this transformation process is a key issue in any model-driven user interface development approach. In this paper, we introduce T:XML, an integrated development environment for managing, creating and previewing transformation rules. The tool supports the specification of transformation rules by using a graphical notation that works on the basis of the transformation of the input model into a graph-based representation. T:XML allows the design and execution of transformation rules in an integrated development environment. Furthermore, the designer can also preview how the generated user interface looks like after the transformations have been applied. These previewing capabilities can be used to quickly create prototypes to discuss with the users in user-centered design methods.

López-Jaquero, Víctor; Montero, Francisco; González, Pascual


Automation on the generation of genome-scale metabolic models.  


Nowadays, the reconstruction of genome-scale metabolic models is a nonautomatized and interactive process based on decision making. This lengthy process usually requires a full year of one person's work in order to satisfactory collect, analyze, and validate the list of all metabolic reactions present in a specific organism. In order to write this list, one manually has to go through a huge amount of genomic, metabolomic, and physiological information. Currently, there is no optimal algorithm that allows one to automatically go through all this information and generate the models taking into account probabilistic criteria of unicity and completeness that a biologist would consider. This work presents the automation of a methodology for the reconstruction of genome-scale metabolic models for any organism. The methodology that follows is the automatized version of the steps implemented manually for the reconstruction of the genome-scale metabolic model of a photosynthetic organism, Synechocystis sp. PCC6803. The steps for the reconstruction are implemented in a computational platform (COPABI) that generates the models from the probabilistic algorithms that have been developed. For validation of the developed algorithm robustness, the metabolic models of several organisms generated by the platform have been studied together with published models that have been manually curated. Network properties of the models, like connectivity and average shortest mean path of the different models, have been compared and analyzed. PMID:23210477

Reyes, R; Gamermann, D; Montagud, A; Fuente, D; Triana, J; Urchueguía, J F; de Córdoba, P Fernández



Molecular modeling of cracks at interfaces in nanoceramic composites  

NASA Astrophysics Data System (ADS)

Toughness in Ceramic Matrix Composites (CMCs) is achieved if crack deflection can occur at the fiber/matrix interface, preventing crack penetration into the fiber and enabling energy-dissipating fiber pullout. To investigate toughening in nanoscale CMCs, direct atomistic models are used to study how matrix cracks behave as a function of the degree of interfacial bonding/sliding, as controlled by the density of C interstitial atoms, at the interface between carbon nanotubes (CNTs) and a diamond matrix. Under all interface conditions studied, incident matrix cracks do not penetrate into the nanotube. Under increased loading, weaker interfaces fail in shear while stronger interfaces do not fail and, instead, the CNT fails once the stress on the CNT reaches its tensile strength. An analytic shear lag model captures all of the micromechanical details as a function of loading and material parameters. Interface deflection versus fiber penetration is found to depend on the relative bond strengths of the interface and the CNT, with CNT failure occurring well below the prediction of the toughness-based continuum He-Hutchinson model. The shear lag model, in contrast, predicts the CNT failure point and shows that the nanoscale embrittlement transition occurs at an interface shear strength scaling as ?s~?? rather than ?s~? typically prevailing for micron scale composites, where ? and ? are the CNT failure strain and stress, respectively. Interface bonding also lowers the effective fracture strength in SWCNTs, due to formation of defects, but does not play a role in DWCNTs having interwall coupling, which are weaker than SWCNTs but less prone to damage in the outerwall.

Pavia, F.; Curtin, W. A.



Providing user models direct access to interfaces: an exploratory study of a simple interface with implications for HRI and HCI  

Microsoft Academic Search

Models of users are a way to understand and improve the usability of computer interfaces. We present here a model in ACT-R cognitive-modeling language that interacts with a publicly available driving simulation as a simple analog for robot inter- faces. The model interacts with the unmodified Java interface by incorporating a novel use of bitmap parsing. The model's structure starts

Frank E. Ritter; Dirk Van Rooy; Robert St. Amant; K. Simpson



Development of an automated core model for nuclear reactors  

SciTech Connect

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this project was to develop an automated package of computer codes that can model the steady-state behavior of nuclear-reactor cores of various designs. As an added benefit, data produced for steady-state analysis also can be used as input to the TRAC transient-analysis code for subsequent safety analysis of the reactor at any point in its operating lifetime. The basic capability to perform steady-state reactor-core analysis already existed in the combination of the HELIOS lattice-physics code and the NESTLE advanced nodal code. In this project, the automated package was completed by (1) obtaining cross-section libraries for HELIOS, (2) validating HELIOS by comparing its predictions to results from critical experiments and from the MCNP Monte Carlo code, (3) validating NESTLE by comparing its predictions to results from numerical benchmarks and to measured data from operating reactors, and (4) developing a linkage code to transform HELIOS output into NESTLE input.

Mosteller, R.D.



A crack model of a bone cement interface.  


This paper is concerned with the fracture mechanics of a bone-cement interface that includes a cohesive zone effect on the crack faces. This accounts for the experimentally observed strengthening mechanism due to the mechanical interlock between the crack faces. Edge crack models are developed where the cohesive zone is simulated by a continuous or a discrete distribution of linear or nonlinear springs. It is shown that the solution obtained by assuming a homogeneous material is fairly close to the exact solution for the bimaterial interface edge crack problem. On the basis of that approximation, the analysis is conducted for the problem of two interacting edge cracks, one at the interface, and the other one in the cement. The small crack that was observed to initiate in the cement, close to the bone-cement interface, does not affect much the mode I stress-intensity factor at the tip of the interface crack. However it may grow, leading to a catastrophic breakdown of the cement. The analysis and following discussion point out an interdependency between bone-cement interface strength and cement strength not previously appreciated. The suggested crack models provide a framework for quantifying the fracture mechanisms at the bone-cement interface. PMID:6492769

Clech, J P; Keer, L M; Lewis, J L



Automatic Interface Generation Through Interaction, Users, and Devices Modeling  

NASA Astrophysics Data System (ADS)

We present a system for designing Internet based applications that automatically adapt to different devices. We define a model that describes the user interaction in terms of elementary input/output actions. Then, we model devices to implements the user interaction in a multi-device context. Finally, we model users, to further adapt the interface

Bertini, Enrico; Santucci, Giuseppe; Calì, Andrea


Dynamic Modeling and Parameter Identification of a Parallel Haptic Interface  

Microsoft Academic Search

This paper describes the dynamic modeling of a five degree of freedom parallel haptic interface. A novel hand\\/mechanism partition is used to define the mechanism so that the model can be built up from five identical actuator rod models. The dynamic equations for each rod are first derived using the Newton\\/Euler equations and are then linearized to obtain an impedance

Christopher D. Lee; Dale A. Lawrence; Lucy Y. Pao



Finned-Tube Evaporator Model With a Visual Interface.  

National Technical Information Service (NTIS)

This paper presents a finned-tube evaporator model and its utility when equipped with a window-based interface. The modeling scheme is 'tube-by-tube' and allows for specification of complex refrigerant circuits, modeling refrigerant distribution between t...

P. A. Domanski



User interface for ground-water modeling: Arcview extension  

USGS Publications Warehouse

Numerical simulation for ground-water modeling often involves handling large input and output data sets. A geographic information system (GIS) provides an integrated platform to manage, analyze, and display disparate data and can greatly facilitate modeling efforts in data compilation, model calibration, and display of model parameters and results. Furthermore, GIS can be used to generate information for decision making through spatial overlay and processing of model results. Arc View is the most widely used Windows-based GIS software that provides a robust user-friendly interface to facilitate data handling and display. An extension is an add-on program to Arc View that provides additional specialized functions. An Arc View interface for the ground-water flow and transport models MODFLOW and MT3D was built as an extension for facilitating modeling. The extension includes preprocessing of spatially distributed (point, line, and polygon) data for model input and postprocessing of model output. An object database is used for linking user dialogs and model input files. The Arc View interface utilizes the capabilities of the 3D Analyst extension. Models can be automatically calibrated through the Arc View interface by external linking to such programs as PEST. The efficient pre- and postprocessing capabilities and calibration link were demonstrated for ground-water modeling in southwest Kansas.

Tsou, M. -S.; Whittemore, D. O.



The Teallach Tool: Using Models for Flexible User Interface Design  

Microsoft Academic Search

Model-based user interface development environments aim to provide designers with a more systematic approach to user i nterface development using a particular design method. This method is re alised through tools which support the construction and linkage of the support ed models. This paper presents the tools which support the construction o f the Teallach models in the context of

Peter J. Barclay; Tony Griffiths; Jo Mckirdy; Norman W. Paton; Richard Cooper; Jessie B. Kennedy



Diffuse interface model of diffusion-limited crystal growth  

Microsoft Academic Search

A general approach to diffusion-limited crystal growth is proposed. It consists of a modified (nonequilibrium) Cahn-Hilliard representation of the interface coupled to a diffusion equation. Arguments are given as to its superiority over previous models. These are illlustrated in a one-dimensional solution which shows how the system selects a unique interface velocity. The selection can be interpreted as the requirement

Joseph B. Collins; Herbert Levine



Leveraging Conceptual Models of Trust in Automated Systems to Promote `Appropriate Trust' in Autonomic Systems  

Microsoft Academic Search

There are subtle differences between automated and autonomic software systems with respect to the observability of information that supports trust between the system and its operators (designers, administrators, and users). Applying conceptual models of trust developed for human relationships with automated systems directly to autonomic systems is simply inadequate. An autonomic system can, however, be modeled as a composition of

Qin Zhu; Dylan Dawson; Priyanka Agrawal; Hausi A. Müller



Back to the Future: A Non-Automated Method of Constructing Transfer Models  

ERIC Educational Resources Information Center

Representing domain knowledge is important for constructing educational software, and automated approaches have been proposed to construct and refine such models. In this paper, instead of applying automated and computationally intensive approaches, we simply start with existing hand-constructed transfer models at various levels of granularity and…

Feng, Mingyu; Beck, Joseph




Microsoft Academic Search

Three dimensional finite difference time domain modeling (FDTD) has been used for many years in engineering and Earth science applications. The earlier versions were fraught with problems and limitations, including an inability to be used for modeling a broad range of frequencies, difficulty modeling large physical property contrasts between grid cells, and no ability to vary the grid size within

Jeffrey J. Daniels; Robert Lee; YuChan Yi; Rubin Ortega; Kyle Shalek


Automated diagnosis of data-model conflicts using metadata.  


The authors describe a methodology for helping computational biologists diagnose discrepancies they encounter between experimental data and the predictions of scientific models. The authors call these discrepancies data-model conflicts. They have built a prototype system to help scientists resolve these conflicts in a more systematic, evidence-based manner. In computational biology, data-model conflicts are the result of complex computations in which data and models are transformed and evaluated. Increasingly, the data, models, and tools employed in these computations come from diverse and distributed resources, contributing to a widening gap between the scientist and the original context in which these resources were produced. This contextual rift can contribute to the misuse of scientific data or tools and amplifies the problem of diagnosing data-model conflicts. The authors' hypothesis is that systematic collection of metadata about a computational process can help bridge the contextual rift and provide information for supporting automated diagnosis of these conflicts. The methodology involves three major steps. First, the authors decompose the data-model evaluation process into abstract functional components. Next, they use this process decomposition to enumerate the possible causes of the data-model conflict and direct the acquisition of diagnostically relevant metadata. Finally, they use evidence statically and dynamically generated from the metadata collected to identify the most likely causes of the given conflict. They describe how these methods are implemented in a knowledge-based system called GRENDEL and show how GRENDEL can be used to help diagnose conflicts between experimental data and computationally built structural models of the 30S ribosomal subunit. PMID:10495098

Chen, R O; Altman, R B


Automated Diagnosis of Data-Model Conflicts Using Metadata  

PubMed Central

The authors describe a methodology for helping computational biologists diagnose discrepancies they encounter between experimental data and the predictions of scientific models. The authors call these discrepancies data-model conflicts. They have built a prototype system to help scientists resolve these conflicts in a more systematic, evidence-based manner. In computational biology, data-model conflicts are the result of complex computations in which data and models are transformed and evaluated. Increasingly, the data, models, and tools employed in these computations come from diverse and distributed resources, contributing to a widening gap between the scientist and the original context in which these resources were produced. This contextual rift can contribute to the misuse of scientific data or tools and amplifies the problem of diagnosing data-model conflicts. The authors' hypothesis is that systematic collection of metadata about a computational process can help bridge the contextual rift and provide information for supporting automated diagnosis of these conflicts. The methodology involves three major steps. First, the authors decompose the data-model evaluation process into abstract functional components. Next, they use this process decomposition to enumerate the possible causes of the data-model conflict and direct the acquisition of diagnostically relevant metadata. Finally, they use evidence statically and dynamically generated from the metadata collected to identify the most likely causes of the given conflict. They describe how these methods are implemented in a knowledge-based system called Grendel and show how Grendel can be used to help diagnose conflicts between experimental data and computationally built structural models of the 30S ribosomal subunit.

Chen, Richard O.; Altman, Russ B.




Microsoft Academic Search

This essay interrogates the colonial modernity of Anglo-Australian lesbian hegemony through an experimental text which plays with the aesthetics of cyberspace. Mobilizing the hypertext mark up language (HTML) form of the Internet, it spatializes the creative, the erotic, and the political that landscape the vicissitudes of everyday life for a lesbian of Southeast Asian background living in Australia, “interface” performs

Audrey Yue



Using Cognitive Modelling Simulations for User Interface Design Decisions  

Microsoft Academic Search

\\u000a This paper argues for the relevance of cognitive modelling and cognitive architectures to support user interface design decisions.\\u000a From a human-computer interaction point of view, cognitive modelling can have benefits both for theory and model building,\\u000a and for the design and evaluation of systems usability. Cognitive modelling research applied to human-computer interaction\\u000a has two complimentary objectives: 1) to develop theories

Bruno Emond; Robert L. West



Microfluidics on liquid handling stations (?F-on-LHS): an industry compatible chip interface between microfluidics and automated liquid handling stations.  


We describe a generic microfluidic interface design that allows the connection of microfluidic chips to established industrial liquid handling stations (LHS). A molding tool has been designed that allows fabrication of low-cost disposable polydimethylsiloxane (PDMS) chips with interfaces that provide convenient and reversible connection of the microfluidic chip to industrial LHS. The concept allows complete freedom of design for the microfluidic chip itself. In this setup all peripheral fluidic components (such as valves and pumps) usually required for microfluidic experiments are provided by the LHS. Experiments (including readout) can be carried out fully automated using the hardware and software provided by LHS manufacturer. Our approach uses a chip interface that is compatible with widely used and industrially established LHS which is a significant advancement towards near-industrial experimental design in microfluidics and will greatly facilitate the acceptance and translation of microfluidics technology in industry. PMID:23639992

Waldbaur, Ansgar; Kittelmann, Jörg; Radtke, Carsten P; Hubbuch, Jürgen; Rapp, Bastian E



Designing a flexible grid enabled scientific modeling interface.  

SciTech Connect

The Espresso Scientific Modeling Interface (Espresso) is a scientific modeling productivity tool developed from climate modelers. Espresso was designed to be an extensible interface to both scientific models and Grid resources. It also aims to be a contemporary piece of software that relies on's Java CoG Kit for a Grid toolkit, Sun's Java 2 API and is configured using XML. This article covers the design implementation of Espresso's Grid functionality and how it interacts with existing scientific models. The authors give specific examples of how they have designed Espresso to perform climate simulations using the PSU/NCAR MM5 atmospheric model. Plans to incorporate the CCSM and FOAM climate models are also discussed.

Dvorak, M.; Taylor, J.; Mickelson, S.



Improved Sharp Interface Models in Coastal Aquifers of Finite Dimensions  

NASA Astrophysics Data System (ADS)

Coastal aquifer management often involves aquifers of finite dimensions where optimal pumping rates must be calculated through a combined simulation-optimization procedure. Variable-density numerical models are considered more exact than sharp interface models as they better describe the governing flow and transport equations. However, such models are not always preferable in pumping optimization studies, due to their complexity and computational burden. On the other hand, sharp interface models are approximate and can lead to large errors if they are not applied properly, particularly when model boundaries are not treated correctly. The present paper proposes improved sharp interface models considering aquifer boundaries in a proper way. Two sharp interface models are investigated based on the single potential formulation and the Ghyben-Herzberg relation. The first model (Strack, 1976) is based on the assumption of a semi-infinite aquifer with a sea-boundary only. The second model (Mantoglou, 2003) is based on an analytical solution developed for coastal aquifers of finite size and accounts for inland and lateral aquifer boundaries. Next, both models are modified using an empirical correction factor (similar to Pool and Carrera, 2011) which accounts for mixing. A simple pumping optimization problem with a single well in a confined coastal aquifer of finite size with four boundaries (sea, inland and lateral impervious boundaries) is employed. The constraint prevents the toe of the interface to reach the well and the optimal pumping rates are calculated for different locations of the pumping well and different combinations of aquifer parameters. Then the results of the sharp interface models are compared to the 'true' results of the corresponding variable-density numerical model in order to evaluate the performance of the sharp interface models. The results indicate that when the location of the well is close to the sea-boundary, the semi-infinite and the finite sized models produce similar, underestimated optimal solutions. However, when the well is placed inland, or near the lateral boundaries, the semi-infinite model yields much higher pumping rates than the finite sized model which are not always realistic and sustainable. This unrealistic performance is further exacerbated when the correction factor is applied to this model. Furthermore, it is observed that the correction factor is sensitive to different combinations of aquifer parameters in the case of the semi-infinite model. On the other hand, the finite sized sharp interface model of Mantoglou (2003), improved using the correction factor, yields increased and sustainable pumping rates regardless of the well location. This is because this model considers inland and lateral boundaries and is better suited for finite sized aquifers whereas the unrealistic behavior of the semi-infinite model is expected since it neglects those boundaries. We conclude that the finite sized sharp interface model, improved with an appropriate correction factor is a better alternative when applied to aquifers of finite dimensions.

Christelis, Vasileios; Mantoglou, Aristotelis




Microsoft Academic Search

Adapting workflow technologies to support process automation in business organizationsis now on the top of the agenda in many organizations. We propose a conceptual modelfor technology adaptation in this area that stresses both technology-organization fit andtechnology-process fit. The goal of our study is to develop a systematic approach tobusiness process automation that is adaptive to changes in organizational needs and

Edward A. Stohr; J. Leon Zhao



Model Checking, Automated Abstraction, and Compositional Verification of Rebeca Models  

Microsoft Academic Search

Actor-based modeling, with encapsulated active objects which communi- cate asynchronously, is generally recognized to be well-suited for representing concur- rent and distributed systems. In this paper we discuss the actor-based language Rebeca which is based on a formal operational interpretation of the actor model. Its Java-like syntax and object-based style of modeling makes it easy to use for software engineers,

Marjan Sirjani; Ali Movaghar; Amin Shali; Frank S. De Boer



Individual Differences in Response to Automation: The Five Factor Model of Personality  

ERIC Educational Resources Information Center

This study examined the relationship of operator personality (Five Factor Model) and characteristics of the task and of adaptive automation (reliability and adaptiveness--whether the automation was well-matched to changes in task demand) to operator performance, workload, stress, and coping. This represents the first investigation of how the Five…

Szalma, James L.; Taylor, Grant S.



Modeling network architecture and time behavior of Distributed Control Systems in industrial plant automation  

Microsoft Academic Search

In terms of fulfilling the customers' needs, Distributed Control Systems (DCS) have gained increasing significance for automation engineering over the past years. The advantages of DCS, e.g. enhanced dependability, flexibility and configurability, overcome various shortcomings of centralized control systems. However, engineering of heterogeneous networks lacks a modeling notation for automation and engineers and a tool support to calculate the time

B. Vogel-Heuser; S. Feldmann; T. Werner; C. Diedrich



Individual Differences in Response to Automation: The Five Factor Model of Personality  

ERIC Educational Resources Information Center

|This study examined the relationship of operator personality (Five Factor Model) and characteristics of the task and of adaptive automation (reliability and adaptiveness--whether the automation was well-matched to changes in task demand) to operator performance, workload, stress, and coping. This represents the first investigation of how the Five…

Szalma, James L.; Taylor, Grant S.



Critical interfaces and duality in the Ashkin-Teller model  

SciTech Connect

We report on the numerical measures on different spin interfaces and Fortuin-Kasteleyn (FK) cluster boundaries in the Askhin-Teller (AT) model. For a general point on the AT critical line, we find that the fractal dimension of a generic spin cluster interface can take one of four different possible values. In particular we found spin interfaces whose fractal dimension is d{sub f}=3/2 all along the critical line. Furthermore, the fractal dimension of the boundaries of FK clusters was found to satisfy all along the AT critical line a duality relation with the fractal dimension of their outer boundaries. This result provides clear numerical evidence that such duality, which is well known in the case of the O(n) model, exists in an extended conformal field theory.

Picco, Marco [Laboratoire de Physique Theorique et Hautes Energies, CNRS, Universite Pierre et Marie Curie, UMR 7589, 4 Place Jussieu, F-75252 Paris Cedex 05 (France); Santachiara, Raoul [Laboratoire de Physique Theorique et Modeles Statistiques, CNRS, Batiment 100, Universite Paris-Sud, UMR 8626, F-91405 Orsay (France)



Relaxing gap capacitor models of electrified interfaces  

NASA Astrophysics Data System (ADS)

Relaxing gap capacitor models emphasize the charge-induced variation of the effective gap of electric double layer capacitors. The first such model, the elastic capacitor, resolved the theoretical puzzle of negative differential capacitance by linking its origin to the charge-induced contraction of the effective gap. It also revealed the importance of treating the electrode charge density as a self-adjustable equilibrium quantity rather than as an independently fixed variable. We show that negative differential capacitance for fixed electrode charge density leads to a charging instability for fixed applied voltage. The ``squishy capacitor'' model, which allows for lateral variation of the effective gap, relates negative differential capacitance to instabilities in isolated systems, with a resultant lateral redistribution of surface charge. We review the origin of negative differential capacitance, discuss charging instabilities, and explore the analogy between the critical behavior of the squishy capacitor and first-order phase transitions.

Partenskii, M. B.; Jordan, P. C.



Practical software model checking via dynamic interface reduction  

Microsoft Academic Search

Implementation-level software model checking explores the state space of a system implementation directly to find potential software defects without requiring any specification or modeling. Despite early successes, the effectiveness of this approach remains severely constrained due to poor scalability caused by state-space explosion. DeMeter makes software model checking more practical with the following contributions: (i) proposing dynamic interface reduction, a

Huayang Guo; Ming Wu; Lidong Zhou; Gang Hu; Junfeng Yang; Lintao Zhang



Multimodal Interfaces: A Survey of Principles, Models and Frameworks  

Microsoft Academic Search

The grand challenge of multimodal interface creation is to build reliable processing systems able to analyze and understand multiple communication means in real-time. This opens a number of associated issues covered by this chapter, such as heterogeneous data types fusion, architectures for real-time processing, dialog management, machine learning for multimodal interaction, modeling languages, frameworks, etc. This chapter does not intend

Bruno Dumas; Denis Lalanne; Sharon L. Oviatt



Model-driven approach for user interface: business alignment  

Microsoft Academic Search

Organizations that adopt Business Process (BP) modeling as a source to implement enterprise systems struggle to maintain such a link. However, not all types of organizations are structured for professionals to adequately manage processes and supporting systems. Even though there are techniques to align business processes and systems, there lacks a solution that addresses User Interfaces (UI). The negative impact

Kênia Sousa



Understanding and modelling built environments for mobile guide interface design  

Microsoft Academic Search

The research presented in this paper aims to inform interface design for mobile guides by understanding and modelling the built environments in which the guide will be used. This is important because research into the use of mobile guides has shown that people have a strong ability to make sense of the physical space in which they are situated and

Jeni Paay; Jesper Kjeldskov



A project interface buffering model for application engineer management  

Microsoft Academic Search

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

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



A receding interface model for the drying of slurry droplets  

Microsoft Academic Search

A receding interface model of the drying of single drops of slurries of sodium sulfate decahydrate has been developed to describe the drying characteristics of this material and to estimate the drying rates of particulate slurries. The simultaneous heat and mass transfer rate equations have been solved numerically, and the results obtained have been compared with those obtained experimentally by

H. W. Cheong; G. V. Jeffreys; C. J. Mumford



A compact model for binary oxides-based memristive interfaces  

NASA Astrophysics Data System (ADS)

We report the resistive switching (RS) characteristics of Al/TiO2/Au memristive cells fabricated in a crossbar array. The measured R-V curves suggest that RS takes place essentially at the Au/TiO2 interface. We propose a model based on the electric field enhanced migration of oxygen vacancies at that interface which reproduces the main features of the experimental data, namely the remnant resistance states and the degradation process. Obtained vacancy profiles at the active region of the junction give insight for the design of improved devices.

Ghenzi, Néstor; José Sánchez, María; Levy, Pablo



Industrial Automation Mechanic Model Curriculum Project. Final Report.  

ERIC Educational Resources Information Center

This document describes a demonstration program that developed secondary level competency-based instructional materials for industrial automation mechanics. Program activities included task list compilation, instructional materials research, learning activity packet (LAP) development, construction of lab elements, system implementation,…

Toledo Public Schools, OH.


Industrial Automation Mechanic Model Curriculum Project. Final Report.  

ERIC Educational Resources Information Center

|This document describes a demonstration program that developed secondary level competency-based instructional materials for industrial automation mechanics. Program activities included task list compilation, instructional materials research, learning activity packet (LAP) development, construction of lab elements, system implementation,…

Toledo Public Schools, OH.


First-principles modeling of magnetic misfit interfaces  

NASA Astrophysics Data System (ADS)

We investigate the structural and magnetic properties of interfaces with large lattice mismatch, choosing Pt/Co and Au/Co as prototypes. For our first-principles calculations, we reduce the lattice mismatch to 0.2% by constructing Moiré supercells. Our results show that the roughness and atomic density, and thus the magnetic properties, depend strongly on the substrate and thickness of the Co slab. An increasing thickness leads to the formation of a Co transition layer at the interface, especially for Pt/Co due to strong Pt-Co interaction. A Moiré supercell with a transition layer is found to reproduce the main experimental findings and thus turns out to be the appropriate model for simulating magnetic misfit interfaces.

Grytsyuk, Sergiy; Schwingenschlögl, Udo



Automated covariate selection and Bayesian model averaging in population PK\\/PD models  

Microsoft Academic Search

We illustrate the use of ‘reversible jump’ MCMC to automate the process of covariate selection in population PK\\/PD analyses.\\u000a The output from such an approach can be used not only to determine the ‘best’ covariate model for each parameter, but also\\u000a to formally measure the spread of uncertainty across all possible models, and to average inferences across a range of

David J. Lunn



A Hybrid Tool for User Interface Modeling and Prototyping  

NASA Astrophysics Data System (ADS)

Although many methods have been proposed, model-based development methods have only to some extent been adopted for UI design. In particular, they are not easy to combine with user-centered design methods. In this paper, we present a hybrid UI modeling and GUI prototyping tool, which is designed to fit better with IS development and UI design traditions. The tool includes a diagram editor for domain and UI models and an execution engine that integrates UI behavior, live UI components and sample data. Thus, both model-based user interface design and prototyping-based iterative design are supported

Trætteberg, Hallvard


Automated XML-based Test Modelling For Mixed-Signal Circuits  

Microsoft Academic Search

Automated system-level test model approach is introduced, incorporating XML, while making use of interchangeable virtual instruments (IVI) and automatic test markup language (ATML) standards. Integrating basic block models into an automated test framework, targeting specifically mixed-signal ICs, the focus is on abstraction through integrating proven technologies in growing complexity levels. Initial result shows high potential for parallel development of system-level

A. Mellik



Automated MRI segmentation for individualized modeling of current flow in the human head  

NASA Astrophysics Data System (ADS)

Objective. High-definition transcranial direct current stimulation (HD-tDCS) and high-density electroencephalography require accurate models of current flow for precise targeting and current source reconstruction. At a minimum, such modeling must capture the idiosyncratic anatomy of the brain, cerebrospinal fluid (CSF) and skull for each individual subject. Currently, the process to build such high-resolution individualized models from structural magnetic resonance images requires labor-intensive manual segmentation, even when utilizing available automated segmentation tools. Also, accurate placement of many high-density electrodes on an individual scalp is a tedious procedure. The goal was to develop fully automated techniques to reduce the manual effort in such a modeling process. Approach. A fully automated segmentation technique based on Statical Parametric Mapping 8, including an improved tissue probability map and an automated correction routine for segmentation errors, was developed, along with an automated electrode placement tool for high-density arrays. The performance of these automated routines was evaluated against results from manual segmentation on four healthy subjects and seven stroke patients. The criteria include segmentation accuracy, the difference of current flow distributions in resulting HD-tDCS models and the optimized current flow intensities on cortical targets.Main results. The segmentation tool can segment out not just the brain but also provide accurate results for CSF, skull and other soft tissues with a field of view extending to the neck. Compared to manual results, automated segmentation deviates by only 7% and 18% for normal and stroke subjects, respectively. The predicted electric fields in the brain deviate by 12% and 29% respectively, which is well within the variability observed for various modeling choices. Finally, optimized current flow intensities on cortical targets do not differ significantly.Significance. Fully automated individualized modeling may now be feasible for large-sample EEG research studies and tDCS clinical trials.

Huang, Yu; Dmochowski, Jacek P.; Su, Yuzhuo; Datta, Abhishek; Rorden, Christopher; Parra, Lucas C.



Dynamic behavior of interfaces: Modeling with nonequilibrium thermodynamics.  


In multiphase systems the transfer of mass, heat, and momentum, both along and across phase interfaces, has an important impact on the overall dynamics of the system. Familiar examples are the effects of surface diffusion on foam drainage (Marangoni effect), or the effect of surface elasticities on the deformation of vesicles or red blood cells in an arterial flow. In this paper we will review recent work on modeling transfer processes associated with interfaces in the context of nonequilibrium thermodynamics (NET). The focus will be on NET frameworks employing the Gibbs dividing surface model, in which the interface is modeled as a two-dimensional plane. This plane has excess variables associated with it, such as a surface mass density, a surface momentum density, a surface energy density, and a surface entropy density. We will review a number of NET frameworks which can be used to derive balance equations and constitutive models for the time rate of change of these excess variables, as a result of in-plane (tangential) transfer processes, and exchange with the adjoining bulk phases. These balance equations must be solved together with mass, momentum, and energy balances for the bulk phases, and a set of boundary conditions coupling the set of bulk and interface equations. This entire set of equations constitutes a comprehensive continuum model for a multiphase system, and allows us to examine the role of the interfacial dynamics on the overall dynamics of the system. With respect to the constitutive equations we will focus primarily on equations for the surface extra stress tensor. PMID:23672962

Sagis, Leonard M C



Modelling surface rheology of complex interfaces with extended irreversible thermodynamics  

NASA Astrophysics Data System (ADS)

The rheological properties of the interfaces in complex multiphase systems often play a crucial role in the dynamic behavior of these systems. For example, these properties affect the dynamics of emulsions, of dispersions of vesicles, of biological fluids, or of free surface flows. In the past three to four decades a vast amount of literature has been produced dealing with the rheological properties of interfaces stabilized by low molecular weight surfactants, proteins, (bio)polymers, lipids, colloidal particles, and various mixtures of these surface active components. The data of these surface rheological experiments are often analyzed with ad hoc generalizations of rheological models used for the analysis of rheological properties of bulk phases. The validity of these generalizations is in general not discussed. Here we show how the extended irreversible thermodynamics (EIT) formalism can be used to generate a wide range of thermodynamically admissible constitutive models for the surface stress tensor, which not only encompass currently used constitutive models, but also suggest several new ones, particularly useful for modelling the nonlinear response of interfaces.

Sagis, Leonard M. C.



Modeling the Photoionized Interface in Blister H II Regions  

NASA Astrophysics Data System (ADS)

We present a grid of photoionization models for the emission from photoevaporative interfaces between the ionized gas and molecular cloud in blister H II regions. For the density profiles of the emitting gas in the models, we use a general power-law form calculated for photoionized, photoevaporative flows by Bertoldi. We find that the spatial emission-line profiles are dependent on the incident flux, the shape of the ionizing continuum, and the elemental abundances. In particular, we find that the peak emissivity of the [S II] and [N II] lines are more sensitive to the elemental abundances than are the total line intensities. The diagnostics obtained from the grid of models can be used in conjunction with high spatial resolution data to infer the properties of ionized interfaces in blister H II regions. As an example, we consider a location at the tip of an ``elephant trunk'' structure in M16 (the Eagle Nebula) and show how narrowband Hubble Space Telescope Wide Field Planetary Camera 2 (HSTWFPC2) images constrain the H II region properties. We present a photoionization model that explains the ionization structure and emission from the interface seen in these high spatial resolution data.

Sankrit, Ravi; Hester, J. Jeff



Spray Modeling: Augmented Reality Based 3D Modeling Interface for Intuitive and Evolutionary Form Development  

Microsoft Academic Search

We present an intuitive 3D modeling interface for conceptual and evolutionary form development in the early phase of the design process. Through field studies of design modeling projects and physical form-making processes, the \\

Hee-kyoung Jung; Tek-jin Nam; Ho-sung Lee; Seung-yeop Han


Model-based user interface design by example and by interview  

Microsoft Academic Search

Model-based user interface design is centered around a de- scription of application objects and operations at a level of abstraction higher than that of code. A good model can be used to support multiple interfaces, help separate interface and application, describe input sequencing in a simple way, check consistency and completeness of the interface, evalu- ate the interface's speed-of-use, generate

Martin R. Frank; James D. Foley



Model-Based User Interface Design Using Markup Concepts  

Microsoft Academic Search

In the field of model-based development of interactive systems, several approaches have been proposed to integrate task and\\u000a object knowledge into the development process and its underlying representations. This paper follows such an approach with\\u000a a special focus on mobile devices. It presents a concept of device independent user interface design based on the XML-technology.\\u000a The concept is applied to

Andreas Mueller; Peter Forbrig; Clemens H. Cap



Interface modeling in incompressible media using level sets in Escript  

NASA Astrophysics Data System (ADS)

We use a finite element (FEM) formulation of the level set method to model geological fluid flow problems involving interface propagation. Interface problems are ubiquitous in geophysics. Here we focus on a Rayleigh-Taylor instability, namely mantel plumes evolution, and the growth of lava domes. Both problems require the accurate description of the propagation of an interface between heavy and light materials (plume) or between high viscous lava and low viscous air (lava dome), respectively. The implementation of the models is based on Escript which is a Python module for the solution of partial differential equations (PDEs) using spatial discretization techniques such as FEM. It is designed to describe numerical models in the language of PDEs while using computational components implemented in C and C++ to achieve high performance for time-intensive, numerical calculations. A critical step in the solution geological flow problems is the solution of the velocity-pressure problem. We describe how the Escript module can be used for a high-level implementation of an efficient variant of the well-known Uzawa scheme. We begin with a brief outline of the Escript modules and then present illustrations of its usage for the numerical solutions of the problems mentioned above.

Gross, L.; Bourgouin, L.; Hale, A. J.; Mühlhaus, H.-B.



Component-based modeling of systems for automated fault tree generation  

Microsoft Academic Search

One of the challenges in the field of automated fault tree construction is to find an efficient modeling approach that can support modeling of different types of systems without ignoring any necessary details. In this paper, we are going to represent a new system of modeling approach for computer-aided fault tree generation. In this method, every system model is composed

Aref Majdara; Toshio Wakabayashi



A second generation user interface design environment: the model and the runtime architecture  

Microsoft Academic Search

Several obstacles exist in the user interface design process which distract a developer from designing a good user interface. One of the problems is the lack of an application model to keep the designer in perspective with the application. The other problem is having to deal with massive user interface programming to achieve a desired interface and to provide users

Piyawadee Noi Sukaviriya; James D. Foley; Todd Griffith



Formal Model of Automated Teller Machine System Using Z notation  

Microsoft Academic Search

In this paper, importance of formal methods has been demonstrated by applying them in the software development of safety critical systems such as automated teller machine system. We have demonstrated the application and integration of formal methods in existing software engineering life cycle. We have used the proper specification language i.e. Z notation, to ensure the correctness, reliability and consistency

Sofia Kanwal; N. A. Zafar



Physical Parameters of Substorms from Automated Forward Modeling (AFM)  

NASA Astrophysics Data System (ADS)

Automated Forward Modeling (AFM) inverts magnetic data to give physical parameters for electric current flow in near-Earth space. On a meridian, it gives the total electric current crossing it, and latitudinal boundaries. AFM uses nonlinear optimization of parameters of a forward model. Characteristic behaviors of substorms are seen: the current strengthens rapidly at an onset, with electrojet boundary motion. The current rises for approximately 30 minutes, but poleward border expansion progresses slightly faster. Recovery is accompanied by a current decrease, but not poleward retreat of the auroral oval on up to a two- hour timescale. Average characteristics of the current closely follow those of the AL index, with large variation in individual events. Boundary motion is similar to that deduced for the electron aurora from satellite studies. AFM allows both the current strength and the borders to be determined from ground magnetic data alone, generally available on a continuous basis. In this study, 63 separate onsets in 1997 were characterized using AFM on the CANOPUS Churchill meridian. The provisional AL index was also obtained for the same events. The parametrization of Weimer (1993), JGR 99, 11005 was found to be extremely accurate for both AL and meridian current, which is I(MA) = c0 + c_1 te^{pt}, with c0 0.151 MA, c_1 1.63 MA/h, and p -1.98/h. This permits a current/AL relation of I(MA) = -0.0322 - 0.00165 * AL, where we stress that I and AL are averages. Further, on average the equatorward border of the electrojet does not change much at onset, while the poleward border's latitude in central dipole coordinates is well represented by 67.5+4.21*(1.0-e^{-5.47*t}), with t the postonset time in hours. These results agree very well with those of Frey et al. (2004), JGR 109, doi:10.1029/2004JA010607 for electron auroras observed using Image WIC near the onset meridian. AFM permits quantification of electrojet parameters, facilitating their interpretation and comparison to other quantities measured during substorms.

Connors, M.; McPherron, R. L.; Ponto, J.



Bacterial Adhesion to Hexadecane (Model NAPL)-Water Interfaces  

NASA Astrophysics Data System (ADS)

The rates of biodegradation of NAPLs have been shown to be influenced by the adhesion of hydrocarbon- degrading microorganisms as well as their proximity to the NAPL-water interface. Several studies provide evidence for bacterial adhesion or biofilm formation at alkane- or crude oil-water interfaces, but there is a significant knowledge gap in our understanding of the processes that influence initial adhesion of bacteria on to NAPL-water interfaces. In this study bacterial adhesion to hexadecane, and a series of NAPLs comprised of hexadecane amended with toluene, and/or with asphaltenes and resins, which are the surface active fractions of crude oils, were examined using a Microbial Adhesion to Hydrocarbons (MATH) assay. The microorganisms employed were Mycobacterium kubicae, Pseudomonas aeruginosa and Pseudomonas putida, which are hydrocarbon degraders or soil microorganisms. MATH assays as well as electrophoretic mobility measurements of the bacterial cells and the NAPL droplet surfaces in aqueous solutions were conducted at three solution pHs (4, 6 and 7). Asphaltenes and resins were shown to generally decrease microbial adhesion. Results of the MATH assay were not in qualitative agreement with theoretical predictions of bacteria- hydrocarbon interactions based on the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) model of free energy of interaction between the cell and NAPL droplets. In this model the free energy of interaction between two colloidal particles is predicted based on electrical double layer, van der Waals and hydrophobic forces. It is likely that the steric repulsion between bacteria and NAPL surfaces, caused by biopolymers on bacterial surfaces and aphaltenes and resins at the NAPL-water interface contributed to the decreased adhesion compared to that predicted by the XDLVO model.

Ghoshal, S.; Zoueki, C. R.; Tufenkji, N.



A plasticity model for interface friction: application to sheet metal forming  

Microsoft Academic Search

Successful numerical simulations of forming operations require robust and accurate tool-workpiece interface friction models. In this paper we extend the rate-independent, isotropic, isothermal interface friction model proposed by Anand (Anand, L., 1993. A constitutive model for interface friction. Computational Mechanics 12, 197–213) to a rate-dependent formulation. Material parameters in the friction model are determined for lubricated interfaces between Al6111-T4 sheet

B. P. Gearing; H. S. Moon; L. Anand



Analysis of polychlorinated biphenyls in transformer oils by automated on-line coupling reversed phase liquid chromatography-gas chromatography using the through oven transfer adsorption desorption (TOTAD) Interface  

Microsoft Academic Search

An automated method for the direct analysis of polychlorinated biphenyls (PCBs) in transformer oil is presented. The proposed method uses the TOTAD (through oven transfer adsorption desorption) interface for the on-line coupling of reversed phase liquid chromatography and gas chromatography (RPLC-GC). In this fully automated system, the oil is injected directly with no sample pre-treatment step other than dilution with

José Manuel Cortés; Juan C. Andini; Rosa M. Toledano; Carlos Quintero; Jesús Villén; Ana Vázquez



Can EMG machine interface be used to model brain machine interface?  

Microsoft Academic Search

The brain-machine interfaces (BMI) have attracted lots of research efforts with the goal to help individuals with paralysis to regain certain motor functions. Many usability issues of BMI are common to other types of human-machine interfaces. Studying of these interfaces, especially those that have similar semantics would provide valuable insights about how the BMI might be used, before the technology

Jeny Tian; Jiping He



Supporting manufacturing-marketing interface management with a partially automated knowledge base: a precursor to computer-integrated business enterprise  

Microsoft Academic Search

Providing continuity and transparency of decisions across interfaces of domains such as manufacturing and marketing is becoming imperative for competitiveness. Since the issues involved in interface management are not very well understood its practice has not been very successful. In this paper, we explore this problem in a scientific way and establish a set of ‘mappings’ across and within domains

Amiya K. Chakravarty; Sanjoy Ghose



Personal reflections on automation, programming culture, and model-based software engineering  

Microsoft Academic Search

Model-based software engineering (MBSE) is an approach to software development characterized in part by significantly greater\\u000a levels of automation when compared to more traditional development methods. Computer-based tools play a fundamental role in\\u000a a number of key aspects of development, including authoring support (many MBSE languages are predominantly visual), automatic\\u000a or semi-automatic verification, automated translation of specifications into corresponding programs, and

Bran Selic



Automated variable selection methods for logistic regression produced unstable models for predicting acute myocardial infarction mortality  

Microsoft Academic Search

Abstract Objectives: Automated variable selection methods,are frequently used to determine,the independent,predictors of an outcome. The objective of this study was to determine the reproducibility of logistic regression models,developed,using automated,variable selection methods. Study Design and Setting: An initial set of 29 candidate variables were considered for predicting mortality after acute myocardial infarction (AMI). We drew 1,000 bootstrap samples from a dataset

Peter C. Austin; Jack V. Tu


Automated Eukaryotic Gene Structure Annotation Using EVidenceModeler and the Program to Assemble Spliced Alignments  

SciTech Connect

EVidenceModeler (EVM) is presented as an automated eukaryotic gene structure annotation tool that reports eukaryotic gene structures as a weighted consensus of all available evidence. EVM, when combined with the Program to Assemble Spliced Alignments (PASA), yields a comprehensive, configurable annotation system that predicts protein-coding genes and alternatively spliced isoforms. Our experiments on both rice and human genome sequences demonstrate that EVM produces automated gene structure annotation approaching the quality of manual curation.

Haas, B J; Salzberg, S L; Zhu, W; Pertea, M; Allen, J E; Orvis, J; White, O; Buell, C R; Wortman, J R



Behavior of asphaltene model compounds at w/o interfaces.  


Asphaltenes, present in significant amounts in heavy crude oil, contains subfractions capable of stabilizing water-in-oil emulsions. Still, the composition of these subfractions is not known in detail, and the actual mechanism behind emulsion stability is dependent on perceived interfacial concentrations and compositions. This study aims at utilizing polyaromatic surfactants which contains an acidic moiety as model compounds for the surface-active subfraction of asphaltenes. A modified pulse-field gradient (PFG) NMR method has been used to study droplet sizes and stability of emulsions prepared with asphaltene model compounds. The method has been compared to the standard microscopy droplet counting method. Arithmetic and volumetric mean droplet sizes as a function of surfactant concentration and water content clearly showed that the interfacial area was dependent on the available surfactant at the emulsion interface. Adsorption of the model compounds onto hydrophilic silica has been investigated by UV depletion, and minor differences in the chemical structure of the model compounds caused significant differences in the affinity toward this highly polar surface. The cross-sectional areas obtained have been compared to areas from the surface-to-volume ratio found by NMR and gave similar results for one of the two model compounds. The mean molecular area for this compound suggested a tilted geometry of the aromatic core with respect to the interface, which has also been proposed for real asphaltenic samples. The film behavior was further investigated using a liquid-liquid Langmuir trough supporting the ability to form stable interfacial films. This study supports that acidic, or strong hydrogen-bonding fractions, can promote stable water-in-oil emulsion. The use of model compounds opens up for studying emulsion behavior and demulsifier efficiency based on true interfacial concentrations rather than perceived interfaces. PMID:19852481

Nordgård, Erland L; Sørland, Geir; Sjöblom, Johan



Thermal Modeling of Roll and Strip Interface in Rolling Processes: Part 2SIMULATION  

Microsoft Academic Search

Part 1 of this paper reviewed the modeling approaches and correlations used to study the interface heat transfer phenomena of the roll-strip contact region in rolling processes. The thermal contact conductance approach was recommended for modeling the interface phenomena. To illustrate, the recommended approach and selected correlations are adopted in the present study for modeling of the roll-strip interface region.

Ampere A. Tseng



An automated method for high-definition transcranial direct current stimulation modeling.  


Targeted transcranial stimulation with electric currents requires accurate models of the current flow from scalp electrodes to the human brain. Idiosyncratic anatomy of individual brains and heads leads to significant variability in such current flows across subjects, thus, necessitating accurate individualized head models. Here we report on an automated processing chain that computes current distributions in the head starting from a structural magnetic resonance image (MRI). The main purpose of automating this process is to reduce the substantial effort currently required for manual segmentation, electrode placement, and solving of finite element models. In doing so, several weeks of manual labor were reduced to no more than 4 hours of computation time and minimal user interaction, while current-flow results for the automated method deviated by less than 27.9% from the manual method. Key facilitating factors are the addition of three tissue types (skull, scalp and air) to a state-of-the-art automated segmentation process, morphological processing to correct small but important segmentation errors, and automated placement of small electrodes based on easily reproducible standard electrode configurations. We anticipate that such an automated processing will become an indispensable tool to individualize transcranial direct current stimulation (tDCS) therapy. PMID:23367144

Huang, Yu; Su, Yuzhuo; Rorden, Christopher; Dmochowski, Jacek; Datta, Abhishek; Parra, Lucas C



Simulated equilibrium and nonequilibrium interfaces in a lattice model  

NASA Astrophysics Data System (ADS)

We have studied the properties of equilibrium and nonequilibrium (d-1)-dimensional interfaces via Monte Carlo simulations of a d-dimensional solid-on-solid model with d=2 and 3. At equilibrium, we examine the intrinsic width of the interface and the interfacial profile as functions of both the lateral size L of the system and the applied gravitational field g; we have studied also the height-height correlation function as a function of both separation and g in two dimensions. Our results are consistent with theories of these properties relying on exact (in an appropriate limit) solution of the model for the case of d=2 and on capillary-wave theory for d=3. The nonequilibrium interfaces studied are those which arise between a growing wetting film and a bulk phase. We look at the intrinsic width of the interface and at the interfacial profile in the large-L limit as functions of time and of the interaction between the substrate and adsorbate. For d-1 equal to both 1 and 2, and for all adsorbate-substrate potentials used, the width grows at a rate which is independent of this potential; the rate is consistent with fluctuation-dominated growth mechanisms. The profiles have the same shape as the equilibrium profiles. In particular we find for d-1=1 that the width varies with time as w~t1/4, which is the same as the rate of growth of the film thickness in the fluctuation regime.

Jiang, Z.; Ebner, C.



Model-Based User Interface Design in the Context of Workflow Models  

Microsoft Academic Search

Within ERP systems, workflow models are used by business analysts to specify which business processes the system supports.\\u000a The workflow model specify which actors that performs what activity in what sequence and the required resources. Within user\\u000a interface (UI) design task models are used to develop task-centric user interfaces. Task-centric UIs can increase systems’\\u000a usability as it focuses on the

Renate Kristiansen; Hallvard Trætteberg



Experimental studies on multiple-model predictive control for automated regulation of hemodynamic variables  

Microsoft Academic Search

A model-based control methodology was developed for automated regulation of mean arterial pressure and cardiac output in critical care subjects using inotropic and vasoactive drugs. The control algorithm used a multiple-model adaptive approach in a model predictive control framework to account for variability and explicitly handle drug rate constraints. The controller was experimentally evaluated on canines that were pharmacologically altered

Ramesh R. Rao; Brian Aufderheide; B. Wayne Bequette



The need for automated formula manipulation in object-oriented continuous-system modeling  

Microsoft Academic Search

Automated formula manipulation is shown to be central to object-oriented continuous-system modeling. Such techniques are needed to (i) solve the causality assignment problem in modeling any kind of energy transducer, (ii) generate the equations that result from the couplings between different objects, (iii) automatically reduce structurally singular models, and (iv) take care of algebraic loops that often result from subsystem

F. E. Cellier; H. Elmqvist



Modeling and control of steering system of heavy vehicles for automated highway systems  

Microsoft Academic Search

This work presents modeling, analysis, and controller design of the steering subsystem of heavy vehicles as a subsystem of vehicle lateral control system for the automated highway systems. A physical model of the steering subsystem is derived where the hydraulic power assist unit is modeled as a family of static nonlinear boost curves. Based on open-loop frequency tests and analysis

Meihua Tai; Pushkar Hingwe; Masayoshi Tomizuka



A Model of Process-Based Automation: Cost and Quality Implications in the Medication Management Process  

ERIC Educational Resources Information Center

|The objective of this research is to understand how a set of systems, as defined by the business process, creates value. The three studies contained in this work develop the model of process-based automation. The model states that complementarities among systems are specified by handoffs in the business process. The model also provides theory to…

Spaulding, Trent Joseph



A biological model for controlling interface growth and morphology.  

SciTech Connect

Biological systems create proteins that perform tasks more efficiently and precisely than conventional chemicals. For example, many plants and animals produce proteins to control the freezing of water. Biological antifreeze proteins (AFPs) inhibit the solidification process, even below the freezing point. These molecules bond to specific sites at the ice/water interface and are theorized to suppress solidification chemically or geometrically. In this project, we investigated the theoretical and experimental data on AFPs and performed analyses to understand the unique physics of AFPs. The experimental literature was analyzed to determine chemical mechanisms and effects of protein bonding at ice surfaces, specifically thermodynamic freezing point depression, suppression of ice nucleation, decrease in dendrite growth kinetics, solute drag on the moving solid/liquid interface, and stearic pinning of the ice interface. Stearic pinning was found to be the most likely candidate to explain experimental results, including freezing point depression, growth morphologies, and thermal hysteresis. A new stearic pinning model was developed and applied to AFPs, with excellent quantitative results. Understanding biological antifreeze mechanisms could enable important medical and engineering applications, but considerable future work will be necessary.

Hoyt, Jeffrey John; Holm, Elizabeth Ann



NIST display interface testbed: the development of a centrally controlled testing system for the automated generation of stimuli and control feedback  

NASA Astrophysics Data System (ADS)

Impressive advances are being made in the field of display metrology, as illustrated in standards such as the Video Electronics Standards Association's Flat Panel Display Measurement standard. However, issues remain regarding the technology-dependent response of display to large-scale signal eros such as noise-induced errors on the data and control lines. The NIST Display Interface Testbed can be used in conjunction with a graphics controller, test generator, or other standard signal source, to inject a user-specified controlled sequence of errors into the interface of a display under test, permitting observation and measurement of the response of the display. In addition to its function as an interface tester, the Testbed effectively serves as a non-intrusive probe into the operation of the display. the programmed control structure of the Testbed permits the convenience of automated test sequences. Development of a feedback mechanisms which allows the test stimulus to be modified in real time, as a function of measurement result and user commands is planned for 1999.

Roberts, John W.; Ward, James A.



A Automated Off-Line Liquid Chromatography/mass Spectrometry Interface Using Solid Phase, Time-Of Secondary Ion Mass Spectrometry.  

NASA Astrophysics Data System (ADS)

The design and construction of an automated off -line interface to couple a microbore HPLC to the Manitoba TOF I SIMS is described. In particular, the details of adapting the electrospray sample deposition method to deposit the eluent of a microbore HPLC column are discussed. Several improvements to the electrospray method were made to improve sensitivity. The spray was focussed and entrained in a nitrogen flow. The use of a hydrophilic boehmite ((AlO)OH) substrate reduced the effect of sodium contamination and increased the relative yield of protonated molecular ions in peptide samples. The design of a microbore HPLC system is described, including details of column plumbing and packing procedures. Comments are made as to the reliability and efficiency of several column packing materials, in this application. The off -line interface was applied to the separation of peptide mixtures produced by trypsin digestion of larger peptides. The products were detected by the mass spectrometry. The fragment ions in the mass spectra were analysed to give sequence information about the parent molecules. The sequence information available was closely correlated with the stability of the protonated molecular ion in the drift region of the spectrometer. The stability of a particular peptide appears to be a function of the residue sequence. The application of the interface to a fully protected peptide and to several steroid hormones is also discussed.

Beavis, Ronald Charles


A symbolic/subsymbolic interface protocol for cognitive modeling.  


Researchers studying complex cognition have grown increasingly interested in mapping symbolic cognitive architectures onto subsymbolic brain models. Such a mapping seems essential for understanding cognition under all but the most extreme viewpoints (namely, that cognition consists exclusively of digitally implemented rules; or instead, involves no rules whatsoever). Making this mapping reduces to specifying an interface between symbolic and subsymbolic descriptions of brain activity. To that end, we propose parameterization techniques for building cognitive models as programmable, structured, recurrent neural networks. Feedback strength in these models determines whether their components implement classically subsymbolic neural network functions (e.g., pattern recognition), or instead, logical rules and digital memory. These techniques support the implementation of limited production systems. Though inherently sequential and symbolic, these neural production systems can exploit principles of parallel, analog processing from decision-making models in psychology and neuroscience to explain the effects of brain damage on problem solving behavior. PMID:20711520

Simen, Patrick; Polk, Thad



A symbolic/subsymbolic interface protocol for cognitive modeling  

PubMed Central

Researchers studying complex cognition have grown increasingly interested in mapping symbolic cognitive architectures onto subsymbolic brain models. Such a mapping seems essential for understanding cognition under all but the most extreme viewpoints (namely, that cognition consists exclusively of digitally implemented rules; or instead, involves no rules whatsoever). Making this mapping reduces to specifying an interface between symbolic and subsymbolic descriptions of brain activity. To that end, we propose parameterization techniques for building cognitive models as programmable, structured, recurrent neural networks. Feedback strength in these models determines whether their components implement classically subsymbolic neural network functions (e.g., pattern recognition), or instead, logical rules and digital memory. These techniques support the implementation of limited production systems. Though inherently sequential and symbolic, these neural production systems can exploit principles of parallel, analog processing from decision-making models in psychology and neuroscience to explain the effects of brain damage on problem solving behavior.

Simen, Patrick; Polk, Thad



Electrode-tissues interface: modeling and experimental validation.  


The electrode-tissues interface (ETI) is one of the key issues in implantable devices such as stimulators and sensors. Once the stimulator is implanted, safety and reliability become more and more critical. In this case, modeling and monitoring of the ETI are required. We propose an empirical model for the ETI and a dedicated integrated circuit to measure its corresponding complex impedance. These measurements in the frequency range of 1 Hz to 100 kHz were achieved in acute dog experiments. The model demonstrates a closer fitting with experimental measurements. In addition, a custom monitoring device based on a stimuli current generator has been completed to evaluate the phase shift and voltage across the electrodes and to transmit wirelessly the values to an external controller. This integrated circuit has been fabricated in a CMOS 0.18 microm process, which consumes 4 mW only during measurements and occupies an area of 1 mm(2). PMID:18458423

Sawan, M; Laaziri, Y; Mounaim, F; Elzayat, E; Corcos, J; Elhilali, M M



Towards automated software model checking using graph transformation systems and Bogor  

Microsoft Academic Search

Graph transformation systems have become a general formal modeling language to describe many models in software development\\u000a process. Behavioral modeling of dynamic systems and model-to-model transformations are only a few examples in which graphs\\u000a have been used to software development. But even the perfect graph transformation system must be equipped with automated analysis\\u000a capabilities to let users understand whether such

Vahid Rafe; Adel T. Rahmani



Data for Environmental Modeling (D4EM): Background and Applications of Data Automation  

EPA Science Inventory

The Data for Environmental Modeling (D4EM) project demonstrates the development of a comprehensive set of open source software tools that overcome obstacles to accessing data needed by automating the process of populating model input data sets with environmental data available fr...


Extraction and use of neural network models in automated synthesis of operational amplifiers  

Microsoft Academic Search

Fast and accurate performance estimation methods are essential to automated synthesis of analog circuits. Development of analog performance models is difficult due to the highly nonlinear nature of various analog performance parameters. This paper presents a neural network-based methodology for creating fast and efficient models for estimating the performance parameters of CMOS operational amplifier topologies. Effective methods for generation and

Glenn Wolfe; Ranga Vemuri



The use of an active appearance model for automated prostate segmentation in magnetic resonance.  


Abstract Background. The prostate gland is delineated as the clinical target volume (CTV) in treatment planning of prostate cancer. Therefore, an accurate delineation is a prerequisite for efficient treatment. Accurate automated prostate segmentation methods facilitate the delineation of the CTV without inter-observer variation. The purpose of this study is to present an automated three-dimensional (3D) segmentation of the prostate using an active appearance model. Material and methods. Axial T2-weighted magnetic resonance (MR) scans were used to build the active appearance model. The model was based on a principal component analysis of shape and texture features with a level-set representation of the prostate shape instead of the selection of landmarks in the traditional active appearance model. To achieve a better fit of the model to the target image, prior knowledge to predict how to correct the model and pose parameters was incorporated. The segmentation was performed as an iterative algorithm to minimize the squared difference between the target and the model image. Results. The model was trained using manual delineations from 30 patients and was validated using leave-one-out cross validation where the automated segmentations were compared with the manual reference delineations. The mean and median dice similarity coefficient was 0.84 and 0.86, respectively. Conclusion. This study demonstrated the feasibility for an automated prostate segmentation using an active appearance with results comparable to other studies. PMID:24007443

Korsager, Anne Sofie; Stephansen, Ulrik Landberg; Carl, Jesper; Ostergaard, Lasse Riis



A Binary Programming Approach to Automated Test Assembly for Cognitive Diagnosis Models  

ERIC Educational Resources Information Center

|Automated test assembly (ATA) has been an area of prolific psychometric research. Although ATA methodology is well developed for unidimensional models, its application alongside cognitive diagnosis models (CDMs) is a burgeoning topic. Two suggested procedures for combining ATA and CDMs are to maximize the cognitive diagnostic index and to use a…

Finkelman, Matthew D.; Kim, Wonsuk; Roussos, Louis; Verschoor, Angela



General Models for Automated Essay Scoring: Exploring an Alternative to the Status Quo  

ERIC Educational Resources Information Center

Powers, Burstein, Chodorow, Fowles, and Kukich (2002) suggested that automated essay scoring (AES) may benefit from the use of "general" scoring models designed to score essays irrespective of the prompt for which an essay was written. They reasoned that such models may enhance score credibility by signifying that an AES system measures the same…

Kelly, P. Adam



Models of Interface Separation Accompanied by Plastic Dissipation at Multiple Scales  

Microsoft Academic Search

Two continuum mechanical models of interface fracture for interfaces joining materials where at least one undergoes plastic\\u000a deformation are reviewed and examined critically. The embedded process zone model (EPZ model) has an adhesive zone, characterized\\u000a by a work of separation and an interface strength, embedded within a continuum model of the adjoining materials. The SSV model\\u000a imposes an elastic, plasticity-free

Yueguang Wei; John W. Hutchinson



A fatigue damage model for the cement-bone interface.  


Loss of fixation at the cement-bone interface can contribute to clinical loosening of cemented total hip replacements. In this study, the fatigue damage response was determined for cement-bone constructs subjected to shear fatigue loading. A typical three-phase fatigue response was observed with substantial early damage, followed by a long constant damage rate region and a final abrupt increase in damage to fracture. All of the damage resulted from creep (permanent) deformation during fatigue loading and there was no loss in cyclic stiffness. Using a Von Mises equivalent stress/strain concept, a general damage model was developed to describe the fatigue creep response of the cement-bone interface under either shear or tensile fatigue loading. Time to failure was highly correlated (r2=0.971) with equivalent creep strain rate and moderately related (r2=0.428) with equivalent initial strain for the two loading regimes. The equivalent creep strain at failure (0.052+/-0.018) was found to be independent of the applied equivalent stress. A combination of the creep damage model (to describe the damage process) with a constant final equivalent strain (as a failure criteria) could be used to assess the cement-bone failure response of cemented implant systems. PMID:15336925

Kim, Do-Gyoon; Miller, Mark A; Mann, Kenneth A



Reliable Modeling of Complex Organic/Metal Interfaces  

NASA Astrophysics Data System (ADS)

The understanding of electronic properties of complex organic/metal interfaces requires a reliable method for the prediction of their structure and stability. The bonding at complex interfaces arises from delicate balance between covalent bonds, van der Waals (vdW) forces, charge transfer, and Pauli repulsion. We developed a method based on density-functional theory with vdW interactions (PBE+vdW^surf [1]) to accurately model adsorbates on surfaces, by a synergetic linkage of the PBE+vdW [2] for intermolecular interactions with the Lifshitz-Zaremba-Kohn theory [3] for the dielectric screening within the substrate surface. This method is demonstrated to reliably model a multitude of molecules on metal surfaces [1,4], leading to an accuracy of 0.1 å in adsorption heights and 0.1 eV in binding energies wrt experiments. To demonstrate the predictive power of the PBE+vdW^surf, we design a novel type of single-molecule push button switch, by carefully controlling the stability and activation barrier between a chemically bound state and a physically bound state for benzene derivatives adsorbed on metal surfaces.[4pt] [1] Ruiz, et al., PRL (2012).[0pt] [2] Tkatchenko and Scheffler, PRL (2009).[0pt] [3] Zaremba and Kohn, PRB (1976).[0pt] [4] Wagner, et al., PRL (2012).

Liu, Wei; Filimonov, Sergey; Ruiz, Victor G.; Scheffler, Matthias; Tkatchenko, Alexandre



Intelligent User Interfaces for Information Analysis: A Cognitive Model  

SciTech Connect

Intelligent user interfaces (IUIs) for information analysis (IA) need to be designed with an intrinsic understanding of the analytical objectives and the dimensions of the information space. These analytical objectives are oriented around the requirement to provide decision makers with courses of action. Most tools available to support analysis barely skim the surface of the dimensions and categories of information used in analysis, and almost none are designed to address the ultimate requirement of decision support. This paper presents a high-level model of the cognitive framework of information analysts in the context of doing their jobs. It is intended that this model will enable the derivation of design requirements for advanced IUIs for IA.

Schwarting, Irene S.; Nelson, Rob A.; Cowell, Andrew J.



ORIGAMI -- The Oak Ridge Geometry Analysis and Modeling Interface  

SciTech Connect

A revised ``ray-tracing`` package which is a superset of the geometry specifications of the radiation transport codes MORSE, MASH (GIFT Versions 4 and 5), HETC, and TORT has been developed by ORNL. Two additional CAD-based formats are also included as part of the superset: the native format of the BRL-CAD system--MGED, and the solid constructive geometry subset of the IGES specification. As part of this upgrade effort, ORNL has designed an Xwindows-based utility (ORIGAMI) to facilitate the construction, manipulation, and display of the geometric models required by the MASH code. Since the primary design criterion for this effort was that the utility ``see`` the geometric model exactly as the radiation transport code does, ORIGAMI is designed to utilize the same ``ray-tracing`` package as the revised version of MASH. ORIGAMI incorporates the functionality of two previously developed graphical utilities, CGVIEW and ORGBUG, into a single consistent interface.

Burns, T.J.



Measurement and modeling of interface heat transfer coefficients  

SciTech Connect

The results of preliminary work on the modeling and measurement of the heat transfer coefficients of metal/mold interfaces is reported. The system investigated is the casting of uranium in graphite molds. The motivation for the work is primarily to improve the accuracy of process modeling of prototype mold designs at the Los Alamos Foundry. The evolution in design of a suitable mold for unidirectional solidification is described, illustrating the value of simulating mold designs prior to use. Experiment indicated a heat transfer coefficient of 2 kW/mS/K both with and without superheat. It was possible to distinguish between solidification due to the mold and that due to radiative heat loss. This permitted an experimental estimate of the emissivity, epsilon = 0.2, of the solidified metal.

Rollett, A.D.; Lewis, H.D.; Dunn, P.S.



Fluctuations of interface statistical physics models applied to a stock market model  

Microsoft Academic Search

In this paper, applying the theory of fluctuations of the interfaces for statistical physics lattice models, we construct a financial model and use this financial model to describe the behavior or fluctuations of a stock price process in a stock market. By using the methods of statistical physics and under some conditions, we show that the finite dimensional distribution of

Jun Wang; Song Deng



Design and implementation of a user-friendly interface for DIII-D neutral beam automated operation.  

National Technical Information Service (NTIS)

The operational interface to the DIII-D neutral beam system, in use for the past 10 years, consisted of several interactive devices that the operator used to sequence neutral beam conditioning and plasma heating shots. Each of four independent MODCOMP Cla...

J. Phillips A. P. Colleraine R. Hong J. Kim R. L. Lee



Combining Compound Conceptual User Interface Components with Modelling Patterns - A Promising Direction for Model-Based Cross-Platform User Interface Development  

Microsoft Academic Search

In this paper we examine why model-based user interface development languages and tools only have had a limited dissemination\\u000a outside the research communities, and argue that there will be an increasing need for cross-platform user interface development\\u000a in the future. To meet these needs, user interface development languages and tools must use new approaches. We examine some\\u000a alternatives, and conclude

Erik G. Nilsson




EPA Science Inventory

The Automated Geospatial Watershed Assessment ( and tool is a GIS interface jointly developed by the U.S. Environmental Protection Agency, USDA-Agricultural Research Service, and the University ...


Measurement and Modeling of Thermal Contact Resistance at a Plastic-Metal Interface  

Microsoft Academic Search

Themal contact resistance(TCR) is a resistance to the flow of heat across the interface of 2 surfaces due to imperfect contact. The TCR at the metal-plastic interface has been shown to affect the modeling of injection molding processes. Its value is strongly dependent on a number of interface parameters including pressure, temperature, the nature of plastic material, the metal surface

L. Sridhar; Kwabena A. Narh



Semi-analytical solution of two-dimensional sharp interface LNAPL transport models  

Microsoft Academic Search

In this paper, we present semi-analytical solutions for two-dimensional equations governing transport of Light Non-Aqueous Phase Liquids (LNAPL) in unconfined aquifers. The proposed model is based on sharp interface displacement and steady groundwater flow assumptions, where both the water–LNAPL interface and the LNAPL–air interface are represented as sharp interfaces. In the case of steady groundwater flow, these equations can be

Boshu Liao; Mustafa M. Aral



Parallelization of a hydrological model using the message passing interface  

USGS Publications Warehouse

With the increasing knowledge about the natural processes, hydrological models such as the Soil and Water Assessment Tool (SWAT) are becoming larger and more complex with increasing computation time. Additionally, other procedures such as model calibration, which may require thousands of model iterations, can increase running time and thus further reduce rapid modeling and analysis. Using the widely-applied SWAT as an example, this study demonstrates how to parallelize a serial hydrological model in a Windows® environment using a parallel programing technology—Message Passing Interface (MPI). With a case study, we derived the optimal values for the two parameters (the number of processes and the corresponding percentage of work to be distributed to the master process) of the parallel SWAT (P-SWAT) on an ordinary personal computer and a work station. Our study indicates that model execution time can be reduced by 42%–70% (or a speedup of 1.74–3.36) using multiple processes (two to five) with a proper task-distribution scheme (between the master and slave processes). Although the computation time cost becomes lower with an increasing number of processes (from two to five), this enhancement becomes less due to the accompanied increase in demand for message passing procedures between the master and all slave processes. Our case study demonstrates that the P-SWAT with a five-process run may reach the maximum speedup, and the performance can be quite stable (fairly independent of a project size). Overall, the P-SWAT can help reduce the computation time substantially for an individual model run, manual and automatic calibration procedures, and optimization of best management practices. In particular, the parallelization method we used and the scheme for deriving the optimal parameters in this study can be valuable and easily applied to other hydrological or environmental models.

Wu, Yiping; Li, Tiejian; Sun, Liqun; Chen, Ji



Retrieving canopy variables by radiative transfer model inversion : an automated regional approach for imaging spectrometer data  

Microsoft Academic Search

A new, automated, regional approach is presented for the estimation of leaf area index, leaf chlorophyll, dry matter, and water content, based on the inversion of the combined leaf and canopy radiative transfer model PROSPECT+SAILh. The approach, named CRASh, is open to different types of imaging spectrometers, although it has been originally designed for airborne hyperspectral sensors with a wide

Wouter Dorigo; Frédéric Baret; Rolf Richter; Gerd Ruecker; Michael Schaepman; A. Mueller



Deadlock-Irrelevant Resource in Petri Nets Models of Automated Manufacturing Systems  

Microsoft Academic Search

Based on Petri net models, this paper concerns the resources which have no connection with the occurrence of system deadlock in automated manufacturing systems. First, the resources concerned are formally defined as the Location-Special resources, because of their special locations. Second, it is proved that these resources have nothing to do with the structural characters, which are called perfect maximal

Hao Yue



Spatial coincidence modelling, automated database updating and data consistency in vector GIS  

Microsoft Academic Search

This thesis presents formal approaches for automated database updating and consistency control in vector- structured spatial databases. To serve as a framework, a conceptual data model is formalized for the representation of geo-data from multiple map layers in which a map layer denotes a set of terrain objects of the same mapping context, e.g., cadastral, soil mapping, etc. The necessity

O. Kufoniyi



A revised empirical model to estimate solar radiation using automated surface weather observations  

Microsoft Academic Search

The transition from manual to automated weather observations at US National Weather Service Offices has compromised the ability to use these data as a means for estimating global horizontal and direct solar radiation. The creation of long term model-derived solar radiation climatologies continues to rely on the in situ cloud data that these observations provide, since homogeneous and readily available

Brian N. Belcher; Arthur T. DeGaetano



Modeling and Formal Specification of Automated Train Control System using Z Notation  

Microsoft Academic Search

In this paper, formal methods which are advanced software engineering techniques, in term of Z notation, are applied for the specification of critical components of automated train control system. At first graph theory is used for modeling of static components of the system and then integrated with Z notation to describe its entire state space. At first real topology is

N. A. Zafar



Automated Test Assembly for Cognitive Diagnosis Models Using a Genetic Algorithm  

ERIC Educational Resources Information Center

|Much recent psychometric literature has focused on cognitive diagnosis models (CDMs), a promising class of instruments used to measure the strengths and weaknesses of examinees. This article introduces a genetic algorithm to perform automated test assembly alongside CDMs. The algorithm is flexible in that it can be applied whether the goal is to…

Finkelman, Matthew; Kim, Wonsuk; Roussos, Louis A.



New Directions in C2 Software Quality Assurance Automation Based on Executable Environment Models  

Microsoft Academic Search

This paper presents some concepts, principles, and techniques for automated testing of real-time reactive software systems based on attributed event grammar (AEG) modeling of the environment in which a system will operate. AEG provides a uniform approach for auto- matic test generation, execution, and analysis. Quantitative and qualitative assessment of the system comprised of the software under test and its

Mikhail Auguston; James Bret Michael; Man-Tak Shing


Automated Port Pricing Model. Volume 1. Executive Summary and Main Report.  

National Technical Information Service (NTIS)

Volume I of the two-volume report contains the Executive Summary and the Main Report. The Executive Summary provides a synoptic overview of the automated port pricing model, highlighting the major features and use. The Main Report presents background info...




Microsoft Academic Search

Automated modeling plays a key role in the realization of intelligent computational tools capable to emulate the human expert's reasoning in pro blem-solving activity aimed at performing tasks in engineering domains. This paper illust rates, through a case study in the domain of visco-elastic materials, how a suitable integrat ion of qualitative, mathematical, sta- tistical, numerical techniques may result in

L. Ironi; S. Tentoni


Significant Distinctions Only: Context-dependent Automated Qualitative Modeling  

Microsoft Academic Search

Qualitative modeling means making the essential distinctions only. Compositional modeling requires to state behavior models of system constituents (e.g components) independently of their context. This creates a problem, because what is essential depends not only on the local model fragment, but also on the context of the model and its usage, i.e. the structure of the entire system and the

Peter Struss; Martin Sachenbacher; Robert Bosch



The OO-method approach for information systems modeling: from object-oriented conceptual modeling to automated programming  

Microsoft Academic Search

Abstract Current and future (conventional) notations used in Conceptual Modeling Techniques should have a precise (formal) semantics to provide a well - defined software development process, in order to go from specification to implementation in an automated way To achieve this objective, the OO - Method approach to Information Systems Modeling presented in this paper attempts to overcome the conventional

Oscar Pastor; Jaime Gómez; Emilio Insfrán; Vicente Pelechano



Model based user interface design for predicting lung cancer treatment outcomes.  


We have developed a web-based tool to predict lung cancer patient's survival probability using previously developed survivability prediction software architecture. Four statistical models are included in this version, three for non-small cell lung cancer and one for limited-stage small cell lung cancer. To make the software tool more accessible and convenient for doctors and patients in a clinical setting, user interfaces are developed using a model based approach. Inputs common to prediction models are placed in interface which appears first, model specific inputs later. This design approach reduced both number of entries per interface and average number of interfaces a user needs to navigate. PMID:22254254

Zhang, Mingrui; Liu, Yingxu; Jiang, Yichen; Sun, Zhifu; Yang, Ping



Does screw-bone interface modelling matter in finite element analyses?  


The effect of screw-bone interface modelling strategies was evaluated in the setting of a tibial mid-shaft fracture stabilised using locking plates. Three interface models were examined: fully bonded interface; screw with sliding contact with bone; and screw with sliding contact with bone in an undersized pilot hole. For the simulation of the last interface condition we used a novel thermal expansion approach to generate the pre-stress that the bone would be exposed to during screw insertion. The study finds that the global load-deformation response is not influenced by the interface modelling approach employed; the deformation varied by less than 1% between different interaction models. However, interface modelling is found to have a considerable impact on the local stress-strain environment within the bone in the vicinity of the screws. Frictional and tied representations did not have significantly different peak strain values (<5% difference); the frictional interface had higher peak compressive strains while the tied interface had higher tensile strains. The undersized pilot hole simulation produced the largest strains. The peak minimum principal strains for the frictional interface were 26% of those for the undersized pilot hole simulation at a load of 770 N. It is concluded that the commonly used tie constraint can be used effectively when the only interest is the global load-deformation behaviour. Different contact interface models, however, alter the mechanical response around screw holes leading to different predictions for screw loosening, bone damage and stress shielding. PMID:22537570

MacLeod, Alisdair R; Pankaj, Pankaj; Simpson, A Hamish R W



Design and Implementation of a Simple Model Interface for Component Based Modeling  

NASA Astrophysics Data System (ADS)

Component based architectures offer an alternative approach for building large, complex hydrologic modeling systems. In contrast to more traditional coding structures (i.e. sequential and modular modeling approaches), component-based modeling allows individuals to construct autonomous computational units that can be linked together through the exchange of shared boundary conditions during run-time. One of the challenges in component-based modeling is designing simple yet robust component interface definitions that allow hydrologic processes to be quickly incorporated into a modeling system. In this study we address this challenge by presenting a new interface design that simplifies the process of implementing the Open Modeling Interface (OpenMI). A component is created by (1) authoring an xml-based configuration file that defines the component's core properties and (2) creating a class that implements the newly defined interface and its three methods: initialize, perform time step, and finish. We will present this approach for creating components and demonstrate how it can be used to create a hydrologic model.

Castronova, A. M.; Goodall, J. L.



Continuity-based model interfacing for plant-wide simulation: A general approach  

Microsoft Academic Search

In plant-wide simulation studies of wastewater treatment facilities, often existing models from different origin need to be coupled. However, as these submodels are likely to contain different state variables, their coupling is not straightforward. The continuity-based interfacing method (CBIM) provides a general framework to construct model interfaces for models of wastewater systems, taking into account conservation principles. In this contribution,

Eveline I. P. Volcke; Mark C. M. van Loosdrecht; Peter A. Vanrolleghem



Efficient Model Checking by Automated Ordering of Transition Relation Partitions  

Microsoft Academic Search

In symbolic model checking, the behavior of a model to be verified is captured by the transition relation of the state space implied by the model. Unfortunately, the size of the transition relation grows rapidly with the number of states even for small models, rendering them impossible to verify. A recent work (5) described a method for partitioning the transition

Daniel Geist; Ilan Beer



Brain–Machine Interfaces Based on Computational Model  

Microsoft Academic Search

\\u000a The research about brain computer interface or brain machine interface has been widely developed in this decade. Implant methods\\u000a are already used for eye or ear as retinal implant or cochlear implant, these devices stimulate peripheral nerve. In this\\u000a case, the stimulus site is peripheral and the information from each sensor is input signal of the brain. Brain Machine Interface

Yasuharu Koike; Hiroyuki Kambara; Natsue Yoshimura; Duk Shin


Brigade Automated Mission Assignment Model for Theater Level Simulation.  

National Technical Information Service (NTIS)

This thesis models the interaction of nonlinear relationships based upon gathered expert judgments. The model developed reproduces a portion of the military expert's mission assignment decision-making process. Specifically, this thesis illustrates a metho...

G. H. Roby



Automated Acquisition of Lifelike 3D Human Models from Multiple Posture Data  

Microsoft Academic Search

In this paper we propose a method for the automated acquisition of 3D human models for real-time animation. The individual\\u000a to be modelled is placed in a monochrome environment and captured simultaneously by a set of 16 calibrated cameras distributed\\u000a on a metal support above and around the head. A number of image sets is taken from various postures. A

Jochen Wingbermühle; Claus-Eberhard Liedtke; Juri Solodenko



Efficient Parallel Levenberg-Marquardt Model Fitting towards Real-Time Automated Parametric Imaging Microscopy  

PubMed Central

We present a fast, accurate and robust parallel Levenberg-Marquardt minimization optimizer, GPU-LMFit, which is implemented on graphics processing unit for high performance scalable parallel model fitting processing. GPU-LMFit can provide a dramatic speed-up in massive model fitting analyses to enable real-time automated pixel-wise parametric imaging microscopy. We demonstrate the performance of GPU-LMFit for the applications in superresolution localization microscopy and fluorescence lifetime imaging microscopy.

Zhu, Xiang; Zhang, Dianwen



Automated construction of detector models for efficiency interpolation in gamma-ray spectrometry  

Microsoft Academic Search

A method was developed for automated construction of detector models in gamma-ray spectrometry, which can be used in Monte Carlo calculations of efficiency calibration curves. Full-energy peak efficiencies were first measured for different gamma-ray energies and for a given sample–detector arrangement and then calculated by the Monte Carlo method. For these calculations a detector model was employed along with a

T. Vidmar; A. Likar



Automated Extraction of Multi-Energy Domain Reduced-Order Models Demonstrated on Capacitive MEMS Microphones  

Microsoft Academic Search

We present a methodology to systematically extract efficient and physically-based reduced-order models based on a mixed-level simulation approach and demonstrate its practicality for the design of a capacitive MEMS microphone. The method has been implemented in a MATLAB toolbox which starting from a FEM discretization, enables the automated generation of mixed-level VHDL-AMS based macro- models, which can be straightforwardly fed

W. Bedykl; M. Niessnerl; G. Schrag; G. Wachutkal; B. Margesin; A. Faes



Efficient Parallel Levenberg-Marquardt Model Fitting towards Real-Time Automated Parametric Imaging Microscopy.  


We present a fast, accurate and robust parallel Levenberg-Marquardt minimization optimizer, GPU-LMFit, which is implemented on graphics processing unit for high performance scalable parallel model fitting processing. GPU-LMFit can provide a dramatic speed-up in massive model fitting analyses to enable real-time automated pixel-wise parametric imaging microscopy. We demonstrate the performance of GPU-LMFit for the applications in superresolution localization microscopy and fluorescence lifetime imaging microscopy. PMID:24130785

Zhu, Xiang; Zhang, Dianwen



Automated piecewise power-law modeling of biological systems  

Microsoft Academic Search

Recent trends suggest that future biotechnology will increasingly rely on mathematical models of the biological systems under investigation. In particular, metabolic engineering will make wider use of metabolic pathway models in stoichiometric or fully kinetic format. A significant obstacle to the use of pathway models is the identification of suitable process descriptions and their parameters. We recently showed that, at

Anna Machina; Arkady Ponosov; Eberhard O. Voit



Computer-automated multiparadigm modeling in control systems technology  

Microsoft Academic Search

The use of model-based technologies has made it imperative for the development of a feedback control system to deal with many different tasks such as: plant modeling in all its variety; model reduction to achieve a complexity or level of abstraction suitable for the design task at hand; synthesis of control laws that vary from discrete event reactive control to

P. J. Mosterman; J. Sztipanovits; S. Engell



EMTP TACS-FORTRAN interface development for digital controls modeling  

Microsoft Academic Search

A FORTRAN interface to be used with TACS (transient analysis of control systems) in EMTP (electromagnetic transient program) has been developed at Hydro-Quebec to allow the use of FORTRAN language for simulating digital controls for power system components such as static compensators, DC transmission, and relays. The interface has been designed without any time delay between TACS and the FORTRAN

L. X. Bui; S. Casoria; G. Morin; J. Reeve



Modeling of the XOM\\/XMP application programming interface (API)  

Microsoft Academic Search

With the growing complexity of communication protocols, it is increasingly difficult for application developers to interface the applications to the communication stacks across a number of platforms. A common application program interface (API) is needed for the purpose. The API can effectively conceal the complexities of communication protocols and architecture, making it easier for application development. This article presents the

Gee-Swee Poo; Chye-Guan Chew



Automated creation of transparent fuzzy models based on decision trees--application to diabetes diagnosis.  


In this paper we propose a novel approach for the simplification of a fuzzy model. Initially, we employ a methodology for the automated generation of fuzzy models based on decision trees. The methodology is realized in three stages. Initially, a crisp model is created from a decision tree, induced from the data. Then, the crisp model it is transformed to a fuzzy one. Finally, in the third stage, all parameters entering the fuzzy model are optimized. The simplification technique is based on the pruning of the initial decision tree. The proposed approach is applied for diabetes diagnosis and the obtained results indicate its efficiency and effectiveness. PMID:19163539

Tsipouras, Markos G; Exarchos, Themis P; Fotiadis, Dimitrios I



Interfacing click chemistry with automated oligonucleotide synthesis for the preparation of fluorescent DNA probes containing internal xanthene and cyanine dyes.  


Double-labeled oligonucleotide probes containing fluorophores interacting by energy-transfer mechanisms are essential for modern bioanalysis, molecular diagnostics, and in vivo imaging techniques. Although bright xanthene and cyanine dyes are gaining increased prominence within these fields, little attention has thus far been paid to probes containing these dyes internally attached, a fact which is mainly due to the quite challenging synthesis of such oligonucleotide probes. Herein, by using 2'-O-propargyl uridine phosphoramidite and a series of xanthenes and cyanine azide derivatives, we have for the first time performed solid-phase copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click labeling during the automated phosphoramidite oligonucleotide synthesis followed by postsynthetic click reactions in solution. We demonstrate that our novel strategy is rapid and efficient for the preparation of novel oligonucleotide probes containing internally positioned xanthene and cyanine dye pairs and thus represents a significant step forward for the preparation of advanced fluorescent oligonucleotide probes. Furthermore, we demonstrate that the novel xanthene and cyanine labeled probes display unusual and very promising photophysical properties resulting from energy-transfer interactions between the fluorophores controlled by nucleic acid assembly. Potential benefits of using these novel fluorescent probes within, for example, molecular diagnostics and fluorescence microscopy include: Considerable Stokes shifts (40-110?nm), quenched fluorescence of single-stranded probes accompanied by up to 7.7-fold light-up effect of emission upon target DNA/RNA binding, remarkable sensitivity to single-nucleotide mismatches, generally high fluorescence brightness values (FB up to 26), and hence low limit of target detection values (LOD down to <5?nM). PMID:23180379

Astakhova, I Kira; Wengel, Jesper



Comparison of Joint Modeling Approaches Including Eulerian Sliding Interfaces  

SciTech Connect

Accurate representation of discontinuities such as joints and faults is a key ingredient for high fidelity modeling of shock propagation in geologic media. The following study was done to improve treatment of discontinuities (joints) in the Eulerian hydrocode GEODYN (Lomov and Liu 2005). Lagrangian methods with conforming meshes and explicit inclusion of joints in the geologic model are well suited for such an analysis. Unfortunately, current meshing tools are unable to automatically generate adequate hexahedral meshes for large numbers of irregular polyhedra. Another concern is that joint stiffness in such explicit computations requires significantly reduced time steps, with negative implications for both the efficiency and quality of the numerical solution. An alternative approach is to use non-conforming meshes and embed joint information into regular computational elements. However, once slip displacement on the joints become comparable to the zone size, Lagrangian (even non-conforming) meshes could suffer from tangling and decreased time step problems. The use of non-conforming meshes in an Eulerian solver may alleviate these difficulties and provide a viable numerical approach for modeling the effects of faults on the dynamic response of geologic materials. We studied shock propagation in jointed/faulted media using a Lagrangian and two Eulerian approaches. To investigate the accuracy of this joint treatment the GEODYN calculations have been compared with results from the Lagrangian code GEODYN-L which uses an explicit treatment of joints via common plane contact. We explore two approaches to joint treatment in the code, one for joints with finite thickness and the other for tight joints. In all cases the sliding interfaces are tracked explicitly without homogenization or blending the joint and block response into an average response. In general, rock joints will introduce an increase in normal compliance in addition to a reduction in shear strength. In the present work we consider the limiting case of stiff discontinuities that only affect the shear strength of the material.

Lomov, I; Antoun, T; Vorobiev, O



Descriptive Evaluation of Automated Software Cost-Estimation Models.  

National Technical Information Service (NTIS)

The purpose of this report is to encourage and facilitate the use of appropriate software cost and schedule models in the Department of Defense. This report provides an introduction to the usefulness of these models and an evaluation of current, fully sup...

E. K. Bailey T. P. Frazier J. W. Bailey



Developing Automated Helicopter Models Using Simulated Annealing and Genetic Search  

Microsoft Academic Search

A heuristic technique is presented that applies simulated annealing search to derive mathematical equations that model a pilot for an X-CELL 60 helicopter. The technique uses a pre-defined alphabet of formulas and combines them to create a mathematical model of the system controller or pilot. The proposed technique provides a new tool that can be used to develop an accurate

Namir Aldawoodi; Rafael Perez; Kimon Valavanis; Wendy Alvis


Multiple mental models, automation strategies, and intelligent vehicle systems  

Microsoft Academic Search

An automobile driver interprets and responds to sensory input according to the context established by a mental model-an internal representation employed to encode, predict, and evaluate the consequences of perceived and intended changes to the operator's current state within the dynamic environment. Skilled driving is organized into behavioral quanta that correspond to separate mental models, each with their own perceptually

Michael A. Goodrich; Erwin R. Boer



Automated parameter extraction software for advanced IGBT modeling  

Microsoft Academic Search

A software package for extracting parameters to be used in advanced IGBT models is presented. In addition, new model equations and extraction procedures are introduced that more accurately describe a wide range of IGBT types including the Warp-Speed IGBTs. The parameter extraction software package consists of five programs that extract the 20 physical and structural parameters needed in the most

S. Bouche



GLEAN: a computer-based tool for rapid GOMS model usability evaluation of user interface designs  

Microsoft Academic Search

Engineering models of human performance permit some aspects of usability of interface designs to be predicted from an analysis of the task, and thus can replace to some extent expensive user testing data. The best developed such tools are GOMS models, which have been shown to be accurate and effective in predicting usability of the procedural aspects of interface designs.

David E. Kieras; Scott D. Wood; Kasem Abotel; Anthony J. Hornof



A simple model for separating interface and oxide charge effects in MOS device characteristics  

Microsoft Academic Search

A simple model to describe radiation effects on MOSFET electrical characteristics is presented. The key assumption is that mobility degradation in an enhancement mode MOSFET is predominantly due to charged interface traps. Model predictions are compared with measured values of interface trap density and device I - V curves.

K. F. Galloway; M. Gaitan; T. J. Russell



A simple model for separating interface and oxide charge effects in MOS device characteristics  

Microsoft Academic Search

A simple model to describe radiation effects on MOSFET electrical characteristics is presented. The key assumption is that mobility degradation in an enhancement mode MOSFET is predominantly due to charged interface traps. Model predictions are compared with measured values of interface trap density and device I-V curves.

K. F. Galloway; M. Gaitan; T. J. Russell



Interface controlled plastic flow modelled by strain gradient plasticity theory  

NASA Astrophysics Data System (ADS)

The resistance to plastic flow in metals is often dominated by the presence of interfaces which interfere with dislocation nucleation and motion. Interfaces can be static such as grain and phase boundaries or dynamic such as new boundaries resulting from a phase transformation. The interface can be hard and fully impenetrable to dislocations, or soft and partly or fully transparent. The interactions between dislocations and interfaces constitute the main mechanism controlling the strength and strain hardening capacity of many metallic systems especially in very fine microstructures with a high density of interfaces. A phenomenological strain gradient plasticity theory is used to introduce, within a continuum framework, higher order boundary conditions which empirically represent the effect of interfaces on plastic flow. The strength of the interfaces can evolve during the loading in order to enrich the description of their response. The behaviour of single and dual phase steels, with possible TRIP effect, accounting for the interactions with static and dynamic boundaries, is addressed, with a specific focus on the size dependent strength and ductility balance. The size dependent response of weak precipitate free zones surrounding grain boundaries is treated as an example involving more than one microstructural length scale.

Pardoen, Thomas; Massart, Thierry J.


Web Interface for Modeling Fog Oil Dispersion During Training  

NASA Astrophysics Data System (ADS)

Predicting the dispersion of military camouflage training materials-Smokes and Obscurants (SO)-is a rapidly improving science. The Defense Threat Reduction Agency (DTRA) developed the Hazard Prediction and Assessment Capability (HPAC), a software package that allows the modeling of the dispersion of several potentially detrimental materials. ERDC/CERL characterized the most commonly used SO material, fog oil in HPAC terminology, to predict the SO dispersion characteristics in various training scenarios that might have an effect on Threatened and Endangered Species (TES) at DoD installations. To make the configuration more user friendly, the researchers implemented an initial web-interface version of HPAC with a modifiable fog-oil component that can be applied at any installation in the world. By this method, an installation SO trainer can plan the location and time of fog oil training activities and is able to predict the degree to which various areas will be effected, particularly important in ensuring the appropriate management of TES on a DoD installation.

Lozar, Robert C.



Automated shell for management of parametric dispersion/deposition modeling.  

National Technical Information Service (NTIS)

In 1993, the US Army tasked Argonne National Laboratory to perform a study of chemical agent dispersion and deposition for the Chemical Stockpile Emergency Preparedness Program using an existing Army computer model. The study explored a wide range of situ...

R. A. Paddock M. J. G. Absil J. P. Peerenboom D. E. Newsom M. J. North



Numerical simulation of continuum models for fluid-fluid interface dynamics  

NASA Astrophysics Data System (ADS)

This paper is concerned with numerical methods for two-phase incompressible flows assuming a sharp interface model for interfacial stresses. Standard continuum models for the fluid dynamics in the bulk phases, for mass transport of a solute between the phases and for surfactant transport on the interface are given. We review some recently developed finite element methods for the appropriate discretization of such models, e. g., a pressure extended finite element (XFE) space which is suitable to represent the pressure jump, a space-time extended finite element discretization for the mass transport equation of a solute and a surface finite element method (SurFEM) for surfactant transport. Numerical experiments based on level set interface capturing and adaptive multilevel finite element discretization are presented for rising droplets with a clean interface model and a spherical droplet in a Poisseuille flow with a Boussinesq-Scriven interface model.

Gross, S.; Reusken, A.



Automated mask creation from a 3D model using Faethm.  

SciTech Connect

We have developed and implemented a method which given a three-dimensional object can infer from topology the two-dimensional masks needed to produce that object with surface micro-machining. The masks produced by this design tool can be generic, process independent masks, or if given process constraints, specific for a target process. This design tool calculates the two-dimensional mask set required to produce a given three-dimensional model by investigating the vertical topology of the model.

Schiek, Richard Louis; Schmidt, Rodney Cannon



Sensor Modeling in Parallel Force Feedback Haptic Interfaces  

Microsoft Academic Search

Force feedback can be used to improve force tracking of haptic interfaces. Single degree-of-freedom (DOF) force sensors work well for force tracking in 1 DOF motion, but multiple single-DOF force sensors combine in unintuitive ways. We present force analysis of a parallel 5 DOF haptic interface and discuss the rami fi cations of using 1 DOF sensors versus multi-DOF sensors.

N. L. Bernstein; Dale A. Lawrence; Lucy Y. Pao



Numerical Models of Stopping Ruptures on a Bimaterial Interface  

NASA Astrophysics Data System (ADS)

Using a cross-correlation earthquake relocation technique, Rubin and Gillard (2000) and Rubin (2002) found that the nearest aftershocks of microearthquakes on the San Andreas fault were much more likely (by a ratio of nearly 3:1) to occur to the NW of the mainshock than to the SE. They attributed this asymmetry to the material contrast across the fault and the resulting dynamical reduction in normal stress near the rupture front propagating to the SE (the front moving in the direction of slip of the more compliant medium). Specifically, it was hypothesized that regions of the fault far enough from failure to resist this extra dynamical "kick" would be that much farther from failure once those dynamical stresses decayed. However, analytical (steady-state) models of propagating slip on a bimaterial interface (Weertman, 1980) show that, as with the static stress field, normal stress changes occur only behind the rupture front. The proposed explanation works most simply if the region ahead of the SE rupture front experiences a transient stress favorable for slip. In principal this stress transient could be associated with either rupture growth or arrest. To investigate this further, we ran 2-D numerical models of slip on a bimaterial interface with slip-weakening friction, using the code of Cochard and Rice (2000). The ruptures spontaneously accelerate to the generalized Rayleigh wave speed of the medium, when such exists. During this growth phase, large tensile stresses are indeed restricted to regions of large slip velocity behind the SE-propagating rupture front. Ahead of the rupture front the normal stresses are smaller and compressive. If the rupture front is stopped abruptly, the short-wavelength tensile stress pulse continues to propagate at roughly the same velocity. The above comments also apply in an anti-symmetric sense to the NW rupture front, although there the slip speeds and normal stress changes are lower. If the rupture is stopped by a more gradual reduction in the loading stress, the moving tensile pulse can spawn a decaying slip pulse at the SE front but not the NW. If this slip pulse marks the furthest extent of slip, the resulting static stress field is quite asymmetric even for a symmetric initial stress, lying on the failure envelope at the NW end of the rupture but well below it at the SE end. These results are at least permissive of the explanation proposed by Rubin and Gillard. For weaker slip pulses (due to any of a number of factors contributing to smaller maximum slip speeds), the furthest extent of slip near the SE rupture front can be driven by the stopping phase arriving from the NW end of the crack. Under such conditions the final stress field is more symmetric. We will be running models using heterogeneous stress fields to explore these questions further, and hope to use rate-and-state friction to investigate the observed temporal decay of the aftershock asymmetry.

Rubin, A. M.; Ampuero, J.



Automated Spatial-Semantic Modeling with Applications to Place Labeling and Informed Search  

Microsoft Academic Search

This paper presents a spatial-semantic modeling sys- tem featuring automated learning of object-place rela- tions from an online annotated database, and the ap- plication of these relations to a variety of real-world tasks. The system is able to label novel scenes with place information, as we demonstrate on test scenes drawn from the same source as our training set. We

Pooja Viswanathan; David Meger; Tristram Southey; James J. Little; Alan K. Mackworth



Automated extraction of multi-energy domain reduced-order models demonstrated on capacitive MEMS microphones  

Microsoft Academic Search

We present a methodology to systematically extract efficient and physically-based reduced-order models based on a mixed-level simulation approach and demonstrate its practicality for the design of a capacitive MEMS microphone. The method has been implemented in a MATLAB toolbox. Starting from a FEM discretization, it enables the automated generation of mixed-level VHDL-AMS based macromodels, which can be straightforwardly fed into

W. Bedyk; M. Niessner; G. Schrag; G. Wachutka; B. Margesin; A. Faes



Automated Forensic Fingerprint Analysis: A Novel Generic Process Model and Container Format  

Microsoft Academic Search

\\u000a The automated forensic analysis of latent fingerprints poses a new challenge. While for the pattern recognition aspects involved,\\u000a the required processing steps can be related to fingerprint biometrics, the common biometric model needs to be extended to\\u000a face the variety of characteristics of different surfaces and image qualities and to keep the chain of custody. Therefore,\\u000a we introduce a framework

Tobias Kiertscher; Claus Vielhauer; Marcus Leich



Automated selection of an accurate model of a visco-elasticmaterial  

Microsoft Academic Search

A major problem in the development of a compu- tationalenvironment that can reason about phys- icalsystems is its abilityto formulate a model . The work here described ispart of a research effort aimed at developing a comprehensive environment that automates the formulation ofthe constitutive law of an actual visco-elasticmaterial. In outline, we approached the problem in two main stages:at first,a

A. C. Capelo; L. Ironi; S. Tentoni


Automated Support for Building and Extending Expert Models  

Microsoft Academic Search

Building a knowledge-based system is like developing a scientific theory. Although a knowledge base does not constitute a theory of some natural phenomenon, it does represent a theory of how a class of professionals approaches an application task. As when scientists develop a natural theory, builders of expert systems first must formulate a model of the behavior that they wish

Mark A. Musen



Synopsis of the Model Making Automation Process Technology  

Microsoft Academic Search

This document provides a synopsis of the unique attributes of MMAP, emphasizing its utilityfor analysis purposes. A definition of the type of distributed system MMAP is best used with isdescribed next so that the model construction obstacles that MMAP overcomes can be highlightedin the following section. Then a description of MMAP is provided. The application of MMAP toanalyzing a Java

Curtis Hrischuk


Automating transition from use-cases to class model  

Microsoft Academic Search

To identify objects from the requirements and to model the problem in classes are critical in object-oriented analysis and design (OOAD). Unfortunately, this is recognized as a hard task for most software engineers, because both domain experience and expertise are needed, since there is no crisp guideline. We present an approach with a set of artifacts and methodologies, and to

Dong Liu; Kalaivani Subramaniam; Behrouz H. Far; Armin Eberlein



Automating defects simulation and fault modeling for SRAMs  

Microsoft Academic Search

The continues improvement in manufacturing process density for very deep sub micron technologies constantly leads to new classes of defects in memory devices. Exploring the effect of fabrication defects in future technologies, and identifying new classes of realistic functional fault models with their corresponding test sequences, is a time consuming task up to now mainly performed by hand. This paper

Stefano Di Carlo; Paolo Prinetto; Alberto Scionti; Zaid Al-Ars



A simplified cellular automation model for city traffic  

SciTech Connect

The authors systematically investigate the effect of blockage sites in a cellular automata model for traffic flow. Different scheduling schemes for the blockage sites are considered. None of them returns a linear relationship between the fraction of green time and the throughput. The authors use this information for a fast implementation of traffic in Dallas.

Simon, P.M.; Nagel, K. [Los Alamos National Lab., NM (United States)]|[Santa Fe Inst., NM (United States)



Automation of sample plan creation for process model calibration  

Microsoft Academic Search

The process of preparing a sample plan for optical and resist model calibration has always been tedious. Not only because it is required to accurately represent full chip designs with countless combinations of widths, spaces and environments, but also because of the constraints imposed by metrology which may result in limiting the number of structures to be measured. Also, there

James Oberschmidt; Amr Abdo; Tamer Desouky; Mohamed Al-Imam; Azalia Krasnoperova; Ramya Viswanathan



Environment behavior models for scenario generation and testing automation  

Microsoft Academic Search

This paper suggests an approach to automatic scenario generation from environment models for testing of real-time reactive systems. The behavior of the system is defined as a set of events (event trace) with two basic relations: precedence and inclusion. The attributed event grammar (AEG) specifies possible event traces and provides a uniform approach for automatically generating, executing, and analyzing test

Mikhail Auguston; James Bret Michael; Man-tak Shing



An Improvement in Thermal Modelling of Automated Tape Placement Process  

NASA Astrophysics Data System (ADS)

The thermoplastic tape placement process offers the possibility of manufacturing large laminated composite parts with all kinds of geometries (double curved i.e.). This process is based on the fusion bonding of a thermoplastic tape on a substrate. It has received a growing interest during last years because of its non autoclave abilities. In order to control and optimize the quality of the manufactured part, we need to predict the temperature field throughout the processing of the laminate. In this work, we focus on a thermal modeling of this process which takes in account the imperfect bonding existing between the different layers of the substrate by introducing thermal contact resistance in the model. This study is leaning on experimental results which inform us that the value of the thermal resistance evolves with temperature and pressure applied on the material.

Barasinski, Anaïs; Leygue, Adrien; Soccard, Eric; Poitou, Arnaud



An Improvement in Thermal Modelling of Automated Tape Placement Process  

SciTech Connect

The thermoplastic tape placement process offers the possibility of manufacturing large laminated composite parts with all kinds of geometries (double curved i.e.). This process is based on the fusion bonding of a thermoplastic tape on a substrate. It has received a growing interest during last years because of its non autoclave abilities.In order to control and optimize the quality of the manufactured part, we need to predict the temperature field throughout the processing of the laminate. In this work, we focus on a thermal modeling of this process which takes in account the imperfect bonding existing between the different layers of the substrate by introducing thermal contact resistance in the model. This study is leaning on experimental results which inform us that the value of the thermal resistance evolves with temperature and pressure applied on the material.

Barasinski, Anaies; Leygue, Adrien; Poitou, Arnaud [GEM, UMR CNRS-Centrale Nantes 1 rue de la Noe, BP 92101, F-44321 Nantes cedex 3 (France); Soccard, Eric [EADS IW, Techno campus EMC2, Allee du Chaffault, 44340 Bouguenais (France)



ADGEN: a system for automated sensitivity analysis of predictive models  

SciTech Connect

A system that can automatically enhance computer codes with a sensitivity calculation capability is presented. With this new system, named ADGEN, rapid and cost-effective calculation of sensitivities can be performed in any FORTRAN code for all input data or parameters. The resulting sensitivities can be used in performance assessment studies related to licensing or interactions with the public to systematically and quantitatively prove the relative importance of each of the system parameters in calculating the final performance results. A general procedure calling for the systematic use of sensitivities in assessment studies is presented. The procedure can be used in modelling and model validation studies to avoid ''over modelling,'' in site characterization planning to avoid ''over collection of data,'' and in performance assessment to determine the uncertainties on the final calculated results. The added capability to formally perform the inverse problem, i.e., to determine the input data or parameters on which to focus additional research or analysis effort in order to improve the uncertainty of the final results, is also discussed.

Pin, F.G.; Horwedel, J.E.; Oblow, E.M.; Lucius, J.L.



Automated target recognition using passive radar and coordinated flight models  

NASA Astrophysics Data System (ADS)

Rather than emitting pulses, passive radar systems rely on illuminators of opportunity, such as TV and FM radio, to illuminate potential targets. These systems are particularly attractive since they allow receivers to operate without emitting energy, rendering them covert. Many existing passive radar systems estimate the locations and velocities of targets. This paper focuses on adding an automatic target recognition (ATR) component to such systems. Our approach to ATR compares the Radar Cross Section (RCS) of targets detected by a passive radar system to the simulated RCS of known targets. To make the comparison as accurate as possible, the received signal model accounts for aircraft position and orientation, propagation losses, and antenna gain patterns. The estimated positions become inputs for an algorithm that uses a coordinated flight model to compute probable aircraft orientation angles. The Fast Illinois Solver Code (FISC) simulates the RCS of several potential target classes as they execute the estimated maneuvers. The RCS is then scaled by the Advanced Refractive Effects Prediction System (AREPS) code to account for propagation losses that occur as functions of altitude and range. The Numerical Electromagnetic Code (NEC2) computes the antenna gain pattern, so that the RCS can be further scaled. The Rician model compares the RCS of the illuminated aircraft with those of the potential targets. This comparison results in target identification.

Ehrman, Lisa M.; Lanterman, Aaron D.



Automated calibration of a stream solute transport model: Implications for interpretation of biogeochemical parameters  

USGS Publications Warehouse

The hydrologic processes of advection, dispersion, and transient storage are the primary physical mechanisms affecting solute transport in streams. The estimation of parameters for a conservative solute transport model is an essential step to characterize transient storage and other physical features that cannot be directly measured, and often is a preliminary step in the study of reactive solutes. Our study used inverse modeling to estimate parameters of the transient storage model OTIS (One dimensional Transport with Inflow and Storage). Observations from a tracer injection experiment performed on Uvas Creek, California, USA, are used to illustrate the application of automated solute transport model calibration to conservative and nonconservative stream solute transport. A computer code for universal inverse modeling (UCODE) is used for the calibrations. Results of this procedure are compared with a previous study that used a trial-and-error parameter estimation approach. The results demonstrated 1) importance of the proper estimation of discharge and lateral inflow within the stream system; 2) that although the fit of the observations is not much better when transient storage is invoked, a more randomly distributed set of residuals resulted (suggesting non-systematic error), indicating that transient storage is occurring; 3) that inclusion of transient storage for a reactive solute (Sr2+) provided a better fit to the observations, highlighting the importance of robust model parameterization; and 4) that applying an automated calibration inverse modeling estimation approach resulted in a comprehensive understanding of the model results and the limitation of input data.

Scott, D. T.; Gooseff, M. N.; Bencala, K. E.; Runkel, R. L.



Flashover of a vacuum-insulator interface: A statistical model  

NASA Astrophysics Data System (ADS)

We have developed a statistical model for the flashover of a 45° vacuum-insulator interface (such as would be found in an accelerator) subject to a pulsed electric field. The model assumes that the initiation of a flashover plasma is a stochastic process, that the characteristic statistical component of the flashover delay time is much greater than the plasma formative time, and that the average rate at which flashovers occur is a power-law function of the instantaneous value of the electric field. Under these conditions, we find that the flashover probability is given by 1-exp(-E?pteffC/k?), where Ep is the peak value in time of the spatially averaged electric field E(t), teff??[E(t)/Ep]?dt is the effective pulse width, C is the insulator circumference, k?exp(?/d), and ? and ? are constants. We define E(t) as V(t)/d, where V(t) is the voltage across the insulator and d is the insulator thickness. Since the model assumes that flashovers occur at random azimuthal locations along the insulator, it does not apply to systems that have a significant defect, i.e., a location contaminated with debris or compromised by an imperfection at which flashovers repeatedly take place, and which prevents a random spatial distribution. The model is consistent with flashover measurements to within 7% for pulse widths between 0.5 ns and 10 ?s, and to within a factor of 2 between 0.5 ns and 90 s (a span of over 11 orders of magnitude). For these measurements, Ep ranges from 64 to 651 kV/cm, d from 0.50 to 4.32 cm, and C from 4.96 to 95.74 cm. The model is significantly more accurate, and is valid over a wider range of parameters, than the J. C. Martin flashover relation that has been in use since 1971 [J. C. Martin on Pulsed Power, edited by T. H. Martin, A. H. Guenther, and M. Kristiansen (Plenum, New York, 1996)]. We have generalized the statistical model to estimate the total-flashover probability of an insulator stack (i.e., an assembly of insulator-electrode systems connected in series). The expression obtained is consistent with the measured flashover performance of a stack of five 5.72-cm-thick, 1003-cm-circumference insulators operated at 100 and 158 kV/cm. The expression predicts that the total-flashover probability is a strong function of the ratio Ep/k, and that under certain conditions, the performance improves as the capacitance between the stack grading rings is increased. In addition, the expression suggests that given a fixed stack height, there exists an optimum number of insulator rings that maximizes the voltage at which the stack can be operated. The results presented can be applied to any system (or any set of systems connected in series) subject to random failures, when the characteristic statistical delay time of a failure is much greater than its formative time.

Stygar, W. A.; Ives, H. C.; Wagoner, T. C.; Lott, J. A.; Anaya, V.; Harjes, H. C.; Corley, J. P.; Shoup, R. W.; Fehl, D. L.; Mowrer, G. R.; Wallace, Z. R.; Anderson, R. A.; Boyes, J. D.; Douglas, J. W.; Horry, M. L.; Jaramillo, T. F.; Johnson, D. L.; Long, F. W.; Martin, T. H.; McDaniel, D. H.; Milton, O.; Mostrom, M. A.; Muirhead, D. A.; Mulville, T. D.; Ramirez, J. J.; Ramirez, L. E.; Romero, T. M.; Seamen, J. F.; Smith, J. W.; Speas, C. S.; Spielman, R. B.; Struve, K. W.; Vogtlin, G. E.; Walsh, D. E.; Walsh, E. D.; Walsh, M. D.; Yamamoto, O.



A versatile interface model for thermal conduction phenomena and its numerical implementation by XFEM  

NASA Astrophysics Data System (ADS)

A general interface model is presented for thermal conduction and characterized by two jump relations. The first one expresses that the temperature jump across an interface is proportional to the interfacial average of the normal heat flux while the second one states that the normal heat flux jump is proportional to the surface Laplacian of the interfacial average of the temperature. By varying the two scalar proportionality parameters, not only the Kapitza resistance and highly conducting interface models can be retrieved but also all the intermediate cases can be covered. The general interface model is numerically implemented by constructing its weak form and by using the level-set method and XFEM. The resulting numerical procedure, whose accuracy and robustness are thoroughly tested and discussed with the help of a benchmark problem, is shown to be efficient for solving the problem of thermal conduction in particulate composites with various imperfect interfaces.

Liu, J. T.; Gu, S. T.; Monteiro, E.; He, Q. C.



Swimming of a model ciliate near an air-liquid interface  

NASA Astrophysics Data System (ADS)

In this work, the role of the hydrodynamic forces on a swimming microorganism near an air-liquid interface is studied. The lubrication theory is utilized to analyze hydrodynamic effects within the narrow gap between a flat interface and a small swimmer. By using an archetypal low-Reynolds-number swimming model called “squirmer,” we find that the magnitude of the vertical swimming velocity is on the order of O(?ln?), where ? is the ratio of the gap width to the swimmer's body size. The reduced swimming velocity near an interface can explain experimental observations of the aggregation of microorganisms near a liquid interface.

Wang, S.; Ardekani, A. M.



Swimming of a model ciliate near an air-liquid interface.  


In this work, the role of the hydrodynamic forces on a swimming microorganism near an air-liquid interface is studied. The lubrication theory is utilized to analyze hydrodynamic effects within the narrow gap between a flat interface and a small swimmer. By using an archetypal low-Reynolds-number swimming model called "squirmer," we find that the magnitude of the vertical swimming velocity is on the order of O(?ln?), where ? is the ratio of the gap width to the swimmer's body size. The reduced swimming velocity near an interface can explain experimental observations of the aggregation of microorganisms near a liquid interface. PMID:23848775

Wang, S; Ardekani, A M




PubMed Central

This paper presents an automated method for actin filament segmentation and tracking for measuring tip elongation rates in Total Internal Reflection Fluorescence Microscopy (TIRFM) images. The main contributions of the paper are: (i) we use a novel open active contour model for filament segmentation and tracking, which is fast and robust against noise; (ii) different strategies are proposed to solve the filament intersection problem, which is shown to be the main difficulty in filament tracking; and (iii) this fully automated method avoids the need of human interaction and thus reduces required time for the entire elongation measurement process on an image sequence. Application to experimental results demonstrated the robustness and effectiveness of this method.

Li, Hongsheng; Shen, Tian; Smith, Matthew B.; Fujiwara, Ikuko; Vavylonis, Dimitrios; Huang, Xiaolei



NeuroGPS: automated localization of neurons for brain circuits using L1 minimization model  

NASA Astrophysics Data System (ADS)

Drawing the map of neuronal circuits at microscopic resolution is important to explain how brain works. Recent progresses in fluorescence labeling and imaging techniques have enabled measuring the whole brain of a rodent like a mouse at submicron-resolution. Considering the huge volume of such datasets, automatic tracing and reconstruct the neuronal connections from the image stacks is essential to form the large scale circuits. However, the first step among which, automated location the soma across different brain areas remains a challenge. Here, we addressed this problem by introducing L1 minimization model. We developed a fully automated system, NeuronGlobalPositionSystem (NeuroGPS) that is robust to the broad diversity of shape, size and density of the neurons in a mouse brain. This method allows locating the neurons across different brain areas without human intervention. We believe this method would facilitate the analysis of the neuronal circuits for brain function and disease studies.

Quan, Tingwei; Zheng, Ting; Yang, Zhongqing; Ding, Wenxiang; Li, Shiwei; Li, Jing; Zhou, Hang; Luo, Qingming; Gong, Hui; Zeng, Shaoqun



NeuroGPS: automated localization of neurons for brain circuits using L1 minimization model  

PubMed Central

Drawing the map of neuronal circuits at microscopic resolution is important to explain how brain works. Recent progresses in fluorescence labeling and imaging techniques have enabled measuring the whole brain of a rodent like a mouse at submicron-resolution. Considering the huge volume of such datasets, automatic tracing and reconstruct the neuronal connections from the image stacks is essential to form the large scale circuits. However, the first step among which, automated location the soma across different brain areas remains a challenge. Here, we addressed this problem by introducing L1 minimization model. We developed a fully automated system, NeuronGlobalPositionSystem (NeuroGPS) that is robust to the broad diversity of shape, size and density of the neurons in a mouse brain. This method allows locating the neurons across different brain areas without human intervention. We believe this method would facilitate the analysis of the neuronal circuits for brain function and disease studies.

Quan, Tingwei; Zheng, Ting; Yang, Zhongqing; Ding, Wenxiang; Li, Shiwei; Li, Jing; Zhou, Hang; Luo, Qingming; Gong, Hui; Zeng, Shaoqun



Analytical modeling of the contact pressure at the steel-concrete interface  

Microsoft Academic Search

This research studies the effect of corrosion on bond strength at the steel-concrete interface in a reinforced concrete member. Bond stress, which can be defined as the shear stress which develops along the lateral surface of the bar, is expressed as a function of contact pressure at the steel-concrete interface. An analytical model of bond which describes the contact pressure

Sini Bhaskar



Cohesive Zone Model Applied to Creep Crack Initiation at an Interface Edge between Submicron Thick Films  

Microsoft Academic Search

A crack initiates at an interface edge between submicron thick films and leads to the malfunction of microelectronic devices. In this study, the cohesive zone model method with a cohesive law based on the damage mechanics concept is developed to simulate the creep crack initiation at an interface edge between tin and silicon films. Experiments on delamination at the Sn\\/Si

Do Van Truong; Takayuki Kitamura



Revisiting heat and salt exchange at the ice-ocean interface: Ocean flux and modeling considerations  

Microsoft Academic Search

Properly describing heat and salt flux at the ice\\/ocean interface is essential for understanding and modeling the energy and mass balance of drifting sea ice. Basal growth or ablation depends on the ratio, R, of the interface heat exchange coefficient to that of salt, such that as R increases so does the rate-limiting impact of salt diffusion. Observations of relatively

M. G. McPhee; J. H. Morison; F. Nilsen



User Models and Information Theory in the Design of a Query Interface for GIS  

Microsoft Academic Search

The design of user interfaces has lacked a firm theoretical foundation. A solid user interface theory would be particularily helpful in complex systems, such as GIS. Information theory and user modelling are presented here as a promising approach to building such a theory. Their applicability is considered in the context of querying a geographical database. Different theories of information are

Mikko Lindholm; Tapani Sarjakoski



Interface mechanics in lower-limb external prosthetics: a review of finite element models  

Microsoft Academic Search

The distribution of mechanical stress at the interface between a residual limb and prosthetic socket is an important design consideration in lower-limb prosthetics. Stresses must be distributed so that the amputee is stable and comfortable, while avoiding trauma to the tissues of the residual limb. Numerical estimation of the stresses at the interface through finite element (FE) modeling can potentially

S. G. Zachariah; J. E. Sanders



Automated drusen detection in retinal images using analytical modelling algorithms  

PubMed Central

Background Drusen are common features in the ageing macula associated with exudative Age-Related Macular Degeneration (ARMD). They are visible in retinal images and their quantitative analysis is important in the follow up of the ARMD. However, their evaluation is fastidious and difficult to reproduce when performed manually. Methods This article proposes a methodology for Automatic Drusen Deposits Detection and quantification in Retinal Images (AD3RI) by using digital image processing techniques. It includes an image pre-processing method to correct the uneven illumination and to normalize the intensity contrast with smoothing splines. The drusen detection uses a gradient based segmentation algorithm that isolates drusen and provides basic drusen characterization to the modelling stage. The detected drusen are then fitted by Modified Gaussian functions, producing a model of the image that is used to evaluate the affected area. Twenty two images were graded by eight experts, with the aid of a custom made software and compared with AD3RI. This comparison was based both on the total area and on the pixel-to-pixel analysis. The coefficient of variation, the intraclass correlation coefficient, the sensitivity, the specificity and the kappa coefficient were calculated. Results The ground truth used in this study was the experts' average grading. In order to evaluate the proposed methodology three indicators were defined: AD3RI compared to the ground truth (A2G); each expert compared to the other experts (E2E) and a standard Global Threshold method compared to the ground truth (T2G). The results obtained for the three indicators, A2G, E2E and T2G, were: coefficient of variation 28.8 %, 22.5 % and 41.1 %, intraclass correlation coefficient 0.92, 0.88 and 0.67, sensitivity 0.68, 0.67 and 0.74, specificity 0.96, 0.97 and 0.94, and kappa coefficient 0.58, 0.60 and 0.49, respectively. Conclusions The gradings produced by AD3RI obtained an agreement with the ground truth similar to the experts (with a higher reproducibility) and significantly better than the Threshold Method. Despite the higher sensitivity of the Threshold method, explained by its over segmentation bias, it has lower specificity and lower kappa coefficient. Therefore, it can be concluded that AD3RI accurately quantifies drusen, using a reproducible method with benefits for ARMD evaluation and follow-up.



DYNAMOS: a numerical MOSFET model including quantum-mechanical and near-interface trap transient effects  

Microsoft Academic Search

A numerical MOSFET model (DYNAMOS) is presented. The present approach accounts for quantum effects in the semiconductor substrate by solving the self-consistent one-dimensional Schrodinger and Poisson equations. It also includes a transient model of interface and near-interface oxide traps based on Schockley–Read–Hall statistics. By extension, this model is able to simulate the charging\\/discharging of an arbitrary trap sheet present in

Pascal Masson; Jean-Luc Autran; Daniela Munteanu



Interface-modified random circuit breaker network model applicable to both bipolar and unipolar resistance switching  

NASA Astrophysics Data System (ADS)

We observed reversible-type changes between bipolar (BRS) and unipolar resistance switching (URS) in one Pt/SrTiOx/Pt capacitor. To explain both BRS and URS in a unified scheme, we introduce the ``interface-modified random circuit breaker network model,'' in which the bulk medium is represented by a percolating network of circuit breakers. To consider interface effects in BRS, we introduce circuit breakers to investigate resistance states near the interface. This percolation model explains the reversible-type changes in terms of connectivity changes in the circuit breakers and provides insights into many experimental observations of BRS which are under debate by earlier theoretical models.

Lee, S. B.; Lee, J. S.; Chang, S. H.; Yoo, H. K.; Kang, B. S.; Kahng, B.; Lee, M.-J.; Kim, C. J.; Noh, T. W.



A biological model for controlling interface growth and morphology  

Microsoft Academic Search

Biological systems create proteins that perform tasks more efficiently and precisely than conventional chemicals. For example, many plants and animals produce proteins to control the freezing of water. Biological antifreeze proteins (AFPs) inhibit the solidification process, even below the freezing point. These molecules bond to specific sites at the ice\\/water interface and are theorized to suppress solidification chemically or geometrically.

Jeffrey John Hoyt; Elizabeth Ann Holm



Cognitive garment design interface using user behavior tree model  

Microsoft Academic Search

An effective user interface helps to hinge on ideas and imagination from fashion designers and most importantly express their artworks with their flair. Shape, material, color, movement and flow - all these qualities give a piece of clothing its uniqueness, and the designer uses drawings to communicate his intentions. Sketches of various views of the garment provide the preliminary clues

Shuang Liang; E. C. L. Chan; G. Baciu; Rong-Hua Li



Structure of liquid-vapor interfaces in the Ising model  

SciTech Connect

The asymptotic behavior of the density profile of the fluid-fluid interface is investigated by computer simulation and is found to be better described by the error function than by the hyperbolic tangent in three dimensions. For higher dimensions the hyperbolic tangent is a better approximation.

Moseley, L.L. [Univ. of the West Indies, Cave Hill (Barbados)



Modeling of Mechanical Interfaces in a Systems Context  

Microsoft Academic Search

The behavior of a technical system depends on the properties of the subsystems and their physical interaction. The interactions take place at interfaces, which may be characterized as conformal or non- conformal depending on how close the mating surfaces fit together. Engineering surfaces are more or less randomly rough. Contact between rough surfaces is, in general, discontinuous and the real

Ulf Sellgren


The significance of cognitive modeling in building healthcare interfaces  

Microsoft Academic Search

Summary Background: Although there are many reasons that widespread adoption of health- care information systems has not transpired, one reason is a failure to take into account the cognitive needs of the users. Aim: To understand the cognitive needs of nurses and physicians and determine how these needs should influence the design of healthcare interfaces. Design of study: A qualitative

Constance M. Johnson; James P. Turley



Guide to the Stand-Damage Model Interface Management System.  

National Technical Information Service (NTIS)

Describes the Gypsy Moth Stand-Damage interface management system. Management of stand-damage data made it necessary to define structures to store data and provide the mechanisms to manipulate these data. The software is used to manipulate files, graph an...

G. Racin J. J. Colbert



Development of interactive graphic user interfaces for modeling reaction-based biogeochemical processes in batch systems with BIOGEOCHEM  

NASA Astrophysics Data System (ADS)

The BIOGEOCHEM numerical model (Yeh and Fang, 2002; Fang et al., 2003) was developed with FORTRAN for simulating reaction-based geochemical and biochemical processes with mixed equilibrium and kinetic reactions in batch systems. A complete suite of reactions including aqueous complexation, adsorption/desorption, ion-exchange, redox, precipitation/dissolution, acid-base reactions, and microbial mediated reactions were embodied in this unique modeling tool. Any reaction can be treated as fast/equilibrium or slow/kinetic reaction. An equilibrium reaction is modeled with an implicit finite rate governed by a mass action equilibrium equation or by a user-specified algebraic equation. A kinetic reaction is modeled with an explicit finite rate with an elementary rate, microbial mediated enzymatic kinetics, or a user-specified rate equation. None of the existing models has encompassed this wide array of scopes. To ease the input/output learning curve using the unique feature of BIOGEOCHEM, an interactive graphic user interface was developed with the Microsoft Visual Studio and .Net tools. Several user-friendly features, such as pop-up help windows, typo warning messages, and on-screen input hints, were implemented, which are robust. All input data can be real-time viewed and automated to conform with the input file format of BIOGEOCHEM. A post-processor for graphic visualizations of simulated results was also embedded for immediate demonstrations. By following data input windows step by step, errorless BIOGEOCHEM input files can be created even if users have little prior experiences in FORTRAN. With this user-friendly interface, the time effort to conduct simulations with BIOGEOCHEM can be greatly reduced.

Chang, C.; Li, M.; Yeh, G.



Phase-field modeling and experimental observation of the irregular interface morphology during directional solidification  

NASA Astrophysics Data System (ADS)

Evolution of the complex solid-liquid interface morphology during a solidification process is an important issue in solidification theory since the morphology eventually dictates the final microstructure of the solidified material and therefore the material properties. Significant progress have been made in recent years in the study of the formation and development of regular dendritic growth, while only limited understanding is achieved for the irregular interface patterns observed in many industry processes. This dissertation focuses on the physical mechanisms of the development and transition of various irregular interface patterns, including the tilted dendritic, the seaweed, and the degenerate patterns. Both experimental observations and numerical simulation using the phase field modeling are performed. A special effort is devoted on the effects of the capillary anisotropy and the kinetic anisotropy in the evolution of the interface morphology during solidification. Experimentally, a directional solidification system is constructed to observe in situ the interface morphology by using the transparent organic material succinonitrile. With such a system, both the regular interface patterns (cellular and dendritic) and the irregular interface patterns (seaweed, degenerate and tilted dendritic) are observed. The effects of the temperature gradient and the interface velocity on the development and transition of the irregular interface patterns are investigated. It is found that the interface morphology transits from the seaweed to the tilted dendritic pattern as the interface velocity increases, while the tilted dendritic pattern may transit to the degenerate seaweed pattern as the temperature gradient increases. Under certain conditions, dendrites and seaweed coexist within the same grain. The dynamic transitions among various patterns and the effect of the solidification conditions are examined in detail. Numerically, a 2-D phase field model is developed to simulate the formation of the irregular interface patterns. Both the capillary anisotropy and the kinetic anisotropy are incorporated into the model. For the first time, the effect of the kinetic anisotropy on the formation of the irregular interface patterns is investigated in the case of a small capillary anisotropy. It has been found that the kinetic anisotropy has a profound influence on the development of the irregular interface patterns. The simulation finds that the interface morphology transits from the cellular into the seaweed and then into the tilted dendritic pattern as the kinetic anisotropy increases. The large angle tilted dendrites are also successfully reproduced. The simulation results agree well with our experimental observations.

Guo, Taiming


Molecular Mobility of the Interface in a Model Composite: A NMR Study.  

National Technical Information Service (NTIS)

The interface of a model polymer composite has been probed using solid-state NMR techniques The adsorption of aminoalkylsilane coupling agents onto silica surfaces and the interaction of these functional silanes with a bismaleimide resin was studied. Carb...

F. D. Blum J. E. Gambogi



Service-Oriented User Interface Modeling and Composition  

Microsoft Academic Search

Traditional service-oriented applications mainly focus on machine-to-machine interaction. However, human-machine interaction in applications also plays an important role. A better user interface can provide better usability and make the system user friendly. A user can be considered a service provider, where the user interaction is a workflow as a part of the system workflow and a user can place SOA

Wei-Tek Tsai; Qian Huang; Jay Elston; Yinong Chen



Toward adaptive conversational interfaces: Modeling speech convergence with animated personas  

Microsoft Academic Search

The design of robust interfaces that process conversational speech is a challenging research direction largely because users' spoken language is so variable. This research explored a new dimension of speaker stylistic variation by examining whether users' speech converges systematically with the text-to-speech (TTS) heard from a software partner. To pursue this question, a study was conducted in which twenty-four 7

Sharon L. Oviatt; Courtney Darves; Rachel Coulston



Keratocyte Apoptosis and Not Myofibroblast Differentiation Mark the Graft/Host Interface at Early Time-Points Post-DSAEK in a Cat Model  

PubMed Central

Purpose To evaluate myofibroblast differentiation as an etiology of haze at the graft-host interface in a cat model of Descemet’s Stripping Automated Endothelial Keratoplasty (DSAEK). Methods DSAEK was performed on 10 eyes of 5 adult domestic short-hair cats. In vivo corneal imaging with slit lamp, confocal, and optical coherence tomography (OCT) were performed twice weekly. Cats were sacrificed and corneas harvested 4 hours, and 2, 4, 6, and 9 days post-DSAEK. Corneal sections were stained with the TUNEL method and immunohistochemistry was performed for ?-smooth muscle actin (?-SMA) and fibronectin with DAPI counterstain. Results At all in vivo imaging time-points, corneal OCT revealed an increase in backscatter of light and confocal imaging revealed an acellular zone at the graft-host interface. At all post-mortem time-points, immunohistochemistry revealed a complete absence of ?-SMA staining at the graft-host interface. At 4 hours, extracellular fibronectin staining was identified along the graft-host interface and both fibronectin and TUNEL assay were positive within adjacent cells extending into the host stroma. By day 2, fibronectin and TUNEL staining diminished and a distinct acellular zone was present in the region of previously TUNEL-positive cells. Conclusions OCT imaging consistently showed increased reflectivity at the graft-host interface in cat corneas in the days post-DSAEK. This was not associated with myofibroblast differentiation at the graft-host interface, but rather with apoptosis and the development of a subsequent acellular zone. The roles of extracellular matrix changes and keratocyte cell death and repopulation should be investigated further as potential contributors to the interface optical changes.

Weis, Adam J.; Huxlin, Krystel R.; Callan, Christine L.; DeMagistris, Margaret A.; Hindman, Holly B.



Towards Real-Time Distributed Signal Modeling for Brain-Machine Interfaces  

Microsoft Academic Search

New architectures for Brain-Machine Interface communication and control use mixture models for expanding rehabilitation capabilities of disabled patients. Here we present and test a dynamic data-driven (BMI) Brain-Machine Interface architecture that relies on multiple pairs of forward-inverse models to predict, control, and learn the trajectories of a robotic arm in a real-time closed- loop system. A method of window-RLS was

Jack Digiovanna; Loris Marchal; Prapaporn Rattanatamrong; Ming Zhao; Shalom Darmanjian; Babak Mahmoudi; Justin C. Sanchez; José C. Príncipe; Linda Hermer-vazquez; Renato J. O. Figueiredo; José A. B. Fortes



An analytical model to project MOS transistor lifetime improvement by deuterium passivation of interface traps  

Microsoft Academic Search

Based on the hydrogen\\/deuterium (H\\/D) isotope effect in interface trap generation and the power law that is widely used to describe the hot-carrier degradation of MOS transistors, a universal model is developed to project the hot-carrier lifetime improvement of MOS transistors by deuterium (D) passivation of interface traps. The validity of this model is verified by comparing its predication with

Kangguo Cheng; Joseph W. Lyding



Streamflow forecasting using the modular modeling system and an object-user interface  

USGS Publications Warehouse

The U.S. Geological Survey (USGS), in cooperation with the Bureau of Reclamation (BOR), developed a computer program to provide a general framework needed to couple disparate environmental resource models and to manage the necessary data. The Object-User Interface (OUI) is a map-based interface for models and modeling data. It provides a common interface to run hydrologic models and acquire, browse, organize, and select spatial and temporal data. One application is to assist river managers in utilizing streamflow forecasts generated with the Precipitation-Runoff Modeling System running in the Modular Modeling System (MMS), a distributed-parameter watershed model, and the National Weather Service Extended Streamflow Prediction (ESP) methodology.

Jeton, A. E.



Automated Metrology for SEM Calibration and CD Line Measurements Using Image Analysis and SEM Modeling Methods  

NASA Astrophysics Data System (ADS)

Due to shrinking size of lithographic feature and limitations of SEM process, the native accuracy of CD-SEM instrument falls outside of ITRS requirements for characterization of lithographic structures for technology node 45 nm and smaller. This work provides overview and feasibility study of metrology system that can deliver accurate CD measurements from CD-SEM by using combination of image metrology and SEM beam modeling methods for automated evaluation and correction of CD-SEM bias. Open issues and further metrology needs are also discussed.

Khvatkov, Vitali; Alievski, Vasily; Kadushnikov, Radi; Babin, Sergey



Measurement and Modeling of Thermal Contact Resistance at a Plastic-Metal Interface  

NASA Astrophysics Data System (ADS)

Themal contact resistance(TCR) is a resistance to the flow of heat across the interface of 2 surfaces due to imperfect contact. The TCR at the metal-plastic interface has been shown to affect the modeling of injection molding processes. Its value is strongly dependent on a number of interface parameters including pressure, temperature, the nature of plastic material, the metal surface characteristics and the presence of interstitial medium such as the mold releasing agents used in injection molding. This study focuses on identifying the inter-relationships among these parameters, by measuring the TCR values for various plastic-metal interfaces under different experimental conditions in order to establish a model that could be used in process modeling and analysis.

Sridhar, L.; Narh, Kwabena A.



PDB_REDO: automated re-refinement of X-ray structure models in the PDB.  


Structural biology, homology modelling and rational drug design require accurate three-dimensional macromolecular coordinates. However, the coordinates in the Protein Data Bank (PDB) have not all been obtained using the latest experimental and computational methods. In this study a method is presented for automated re-refinement of existing structure models in the PDB. A large-scale benchmark with 16?807 PDB entries showed that they can be improved in terms of fit to the deposited experimental X-ray data as well as in terms of geometric quality. The re-refinement protocol uses TLS models to describe concerted atom movement. The resulting structure models are made available through the PDB_REDO databank ( Grid computing techniques were used to overcome the computational requirements of this endeavour. PMID:22477769

Joosten, Robbie P; Salzemann, Jean; Bloch, Vincent; Stockinger, Heinz; Berglund, Ann-Charlott; Blanchet, Christophe; Bongcam-Rudloff, Erik; Combet, Christophe; Da Costa, Ana L; Deleage, Gilbert; Diarena, Matteo; Fabbretti, Roberto; Fettahi, Géraldine; Flegel, Volker; Gisel, Andreas; Kasam, Vinod; Kervinen, Timo; Korpelainen, Eija; Mattila, Kimmo; Pagni, Marco; Reichstadt, Matthieu; Breton, Vincent; Tickle, Ian J; Vriend, Gert



A new method of virtual material hypothesis-based dynamic modeling on fixed joint interface in machine tools  

Microsoft Academic Search

The dynamic characteristics of joint interfaces affect the dynamic behaviors of a whole machine tool structure notably. An analytic method of virtual material hypothesis-based dynamic modeling on fixed joint interface in machine tools was conducted so as to improve the modeling accuracy of whole machine tools. The microcontact part of two contact surfaces in fixed joint interface was assumed as

Hongliang Tian; Bin Li; Hongqi Liu; Kuanmin Mao; Fangyu Peng; Xiaolei Huang



Interface dipole effect on thin film ferroelectric stability: First-principles and phenomenological modeling  

NASA Astrophysics Data System (ADS)

Utilization of the switchable spontaneous polarization of ferroelectric materials offers a promising avenue for the future of nanoelectronic memories and logic devices provided that nanoscale metal-ferroelectric-metal heterostructures can be engineered to maintain a bi-stable polarization switchable by an applied electric field. The most challenging aspect of this approach is to overcome the deleterious interface effects which tend to render ferroelectric polarization either unstable or unswitchable and which become ever more important as ferroelectric materials are produced thinner and thinner. Here we use first-principles density functional calculations and phenomenological modeling to demonstrate that a BaO/RuO2 interface termination sequence in SrRuO3/BaTiO3/SrRuO3 epitaxial heterostructures grown on SrTiO3 can lead to a nonswitchable polarization state for thin BaTiO3 films due to a fixed interface dipole. The unfavorable interface dipole at the BaO/RuO2 interface leads to a strong preference for one polarization state and, in thin film structures, leads to instability of the second state below a certain critical thickness, thereby making the polarization unswitchable. We analyze the contribution of this interface dipole to the energetic stability of these heterostructures. Furthermore, we propose and demonstrate that this unfavorable interface dipole effect can be alleviated by deposition of a thin layer of SrTiO3 at the BaO/RuO2 terminated interface. Our first-principles and phenomenological modeling predict that the associated change of the interface termination sequence to SrO/TiO2 on both sides of the heterostructure leads to a restoration of bi-stability with a smaller critical thickness, along with an enhancement of the barrier for polarization reversal. These results demonstrate that interface engineering is a viable approach to enhance ferroelectric properties at the nanoscale.

Liu, Xiaohui; Wang, Yong; Lukashev, Pavel V.; Burton, J. D.; Tsymbal, Evgeny Y.



A useful automated rainfall-runoff model for engineering applications in semi-arid regions  

NASA Astrophysics Data System (ADS)

This research develops a useful GIS-based automated Semi-Distributed Time-Area model (SDISTA) that is intended for engineering applications in semi-arid regions. SDISTA is a simple model that reconsiders the time-area technique using an improved approach that deals with each grid cell as a completely independent hydrologic unit. Travel times through the grid cells are estimated using a spatially varied grid-based Manning's formula that relates the hydraulic radius at each grid cell to the characteristics of its upstream catchment area and excess rainfall depth. SDISTA is tested in this research on cases from semi-arid regions including Sinai Peninsula. The results show that SDISTA can be as accurate as HEC-1/HEC-HMS using a very dense network. SDISTA is fully automated and requires minimum effort from the user which is very favorable for engineering applications. The most attractive feature of SDISTA is its ability to automatically delineate and simulate any number of catchment areas simultaneously on digital elevation models.

Gad, Mohamed A.



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


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



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

PubMed Central

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

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



Stability of interfaces in a random environment. A rigorous renormalization group analysis of a hierarchical model  

NASA Astrophysics Data System (ADS)

We study a hierarchical model of domain walls in a D-dimensional bond disordered Ising model at low temperatures. Using a renormalization group method inspired by the work of Bricmont and Kupiainen for the random field Ising model, we prove the existence of rigid interfaces at low enough temperatures in dimensions D>3.

Bovier, Anton; Picco, Pierre



Development and interfacing of a generic switched reluctance motor model for an EMTP  

Microsoft Academic Search

The paper presents a simplified model of a switched reluctance motor (SRM) and its generic implementation in a popular electromagnetic transient program. The nonlinear flux linkage-current relationship at a given rotor angle is realized as the weighted sum of magnetic characteristics at two extreme rotor positions. The SRM model is interfaced with the rest of the network (modeled within the

Athula D. Rajapakse; Aniruddha M. Gole; Dharshana Muthumani



Interpreting neural activity through linear and nonlinear models for brain machine interfaces  

Microsoft Academic Search

Brain machine interface (BMI) design can be achieved by training linear and nonlinear models with simultaneously recorded cortical neural activity and behavior (typically the hand position of a primate). We propose the use of optimized BMI models for analyzing neural activity to assess the role of individual neurons and cortical areas in generating the performed movement. Two models (linear-feedforward and

Justin C. Sanchez; Deniz Erdogmus; Yadunandana Rao; Sung-Phil Kim; Miguel Nicolelis; Johan Wessberg; Jose C. Principe



System Operations Studies for Automated Guideway Transit Systems: Discrete Event Simulation Model Programmer's Manual.  

National Technical Information Service (NTIS)

In order to examine specific automated guideway transit (AGT) developments and concepts, UMTA undertook a program of studies and technology investigations called Automated Guideway Transit Technology (AGTT) Program. The objectives of one segment of the AG...

J. F. Duke R. Blanchard



Process Development for Automated Solar Cell and Module Production. Task 4: Automated Array Assembly.  

National Technical Information Service (NTIS)

The Automated Lamination Station is mechanically complete and is currently undergoing final wiring. The high current driver and isolator boards have been completed and installed, and the main interface board is under construction. The automated vacuum cha...

J. J. Hagerty



Using physical potentials and learned models to distinguish native binding interfaces from de novo designed interfaces that do not bind.  


Protein-protein interactions are a fundamental aspect of many biological processes. The advent of recombinant protein and computational techniques has allowed for the rational design of proteins with novel binding capabilities. It is therefore desirable to predict which designed proteins are capable of binding in vitro. To this end, we have developed a learned classification model that combines energetic and non-energetic features. Our feature set is adapted from specialized potentials for aromatic interactions, hydrogen bonds, electrostatics, shape, and desolvation. A binding model built on these features was initially developed for CAPRI Round 21, achieving top results in the independent assessment. Here, we present a more thoroughly trained and validated model, and compare various support-vector machine kernels. The Gaussian kernel model classified both high-resolution complexes and designed nonbinders with 79-86% accuracy on independent test data. We also observe that multiple physical potentials for dielectric-dependent electrostatics and hydrogen bonding contribute to the enhanced predictive accuracy, suggesting that their combined information is much greater than that of any single energetics model. We also study the change in predictive performance as the model features or training data are varied, observing unusual patterns of prediction in designed interfaces as compared with other data types. Proteins 2013; 81:1919-1930. © 2013 Wiley Periodicals, Inc. PMID:23760773

Demerdash, Omar N A; Mitchell, Julie C



Automation, Control and Modeling of Compound Semiconductor Thin-Film Growth  

SciTech Connect

This report documents the results of a laboratory-directed research and development (LDRD) project on control and agile manufacturing in the critical metalorganic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE) materials growth processes essential to high-speed microelectronics and optoelectronic components. This effort is founded on a modular and configurable process automation system that serves as a backbone allowing integration of process-specific models and sensors. We have developed and integrated MOCVD- and MBE-specific models in this system, and demonstrated the effectiveness of sensor-based feedback control in improving the accuracy and reproducibility of semiconductor heterostructures. In addition, within this framework we have constructed ''virtual reactor'' models for growth processes, with the goal of greatly shortening the epitaxial growth process development cycle.

Breiland, W.G.; Coltrin, M.E.; Drummond, T.J.; Horn, K.M.; Hou, H.Q.; Klem, J.F.; Tsao, J.Y.



Toward the virtual cell: Automated approaches to building models of subcellular organization "learned" from microscopy images  

PubMed Central

We review state-of-the-art computational methods for constructing, from image data, generative statistical models of cellular and nuclear shapes and the arrangement of subcellular structures and proteins within them. These automated approaches allow consistent analysis of images of cells for the purposes of learning the range of possible phenotypes, discriminating between them, and informing further investigation. Such models can also provide realistic geometry and initial protein locations to simulations in order to better understand cellular and subcellular processes. To determine the structures of cellular components and how proteins and other molecules are distributed among them, the generative modeling approach described here can be coupled with high throughput imaging technology to infer and represent subcellular organization from data with few a priori assumptions. We also discuss potential improvements to these methods and future directions for research.

Buck, Taraz E.; Li, Jieyue; Rohde, Gustavo K.; Murphy, Robert F.



Mathematical Modeling Research to Support the Development of Automated Insulin-Delivery Systems  

PubMed Central

The world leaders in glycemia modeling convened during the Eighth Annual Diabetes Technology Meeting in Bethesda, Maryland, on 14 November 2008, to discuss the current practices in mathematical modeling and make recommendations for its use in developing automated insulin-delivery systems. This report summarizes the collective views of the 25 participating experts in addressing the following four topics: current practices in modeling efforts for closed-loop control; framework for exchange of information and collaboration among research centers; major barriers for the development of accurate models; and key tasks for developing algorithms to build closed-loop control systems. Among the participants, the following main conclusions and recommendations were widely supported: Physiologic variance represents the single largest technical challenge to creating accurate simulation models.A Web site describing different models and the data supporting them should be made publically available, with funding agencies and journals requiring investigators to provide open access to both models and data.Existing simulation models should be compared and contrasted, using the same evaluation and validation criteria, to better assess the state of the art, understand any inherent limitations in the models, and identify gaps in data and/or model capability.

Steil, Garry M.; Reifman, Jaques



A Wireless Sensor Network Communication Model for Automation of Electric Power Distribution  

Microsoft Academic Search

Automation of electric power distribution in a cost-efficient and reliable manner can be accomplished by complete automation of the load dispatch centers and substations on a large scale. For efficient load balancing among the feed lines, a continuous monitoring of parameters, such as voltage, current in the line, temperature, pressure, and oil level of the transformers is required. Currently, automation

M. Muthukumar; N. Sureshkumar


Dynamic and spatial behavior of a corrugated interface in the driven lattice gas model  

Microsoft Academic Search

The spatiotemporal behavior of an initially corrugated interface in the two-dimensional driven lattice gas (DLG) model with attractive nearest-neighbors interactions is investigated via Monte Carlo simulations. By setting the system in the ordered phase, with periodic boundary conditions along the external field axis. i.e. horizontal, and open along the vertical directions respectively, an initial interface was imposed, that consists in

Gustavo P. Saracco; Ezequiel V. Albano



Interface projection techniques for fluid–structure interaction modeling with moving-mesh methods  

Microsoft Academic Search

The stabilized space–time fluid–structure interaction (SSTFSI) technique developed by the Team for Advanced Flow Simulation\\u000a and Modeling (T?AFSM) was applied to a number of 3D examples, including arterial fluid mechanics and parachute aerodynamics.\\u000a Here we focus on the interface projection techniques that were developed as supplementary methods targeting the computational\\u000a challenges associated with the geometric complexities of the fluid–structure interface.

Tayfun E. Tezduyar; Sunil Sathe; Jason Pausewang; Matthew Schwaab; Jason Christopher; Jason Crabtree



Using the keystroke-level model for designing user interface on middle-sized touch screens  

Microsoft Academic Search

The Keystroke-Level Model was developed to predict accurately task execution time for mouse-and-keyboard systems. Middle-sized touch screens are becoming much more popular so it is important to determine whether KLM can provide useful predictions for these interfaces as well. The KLMs were created using special software CogTool for three touch screen interfaces for integrated control systems and were compared to

Evgeniy Abdulin



The characterization of a proposed model GaAs\\/anodic oxide interface  

Microsoft Academic Search

The n-GaAs\\/anodic oxide interface has been characterized using capacitance-voltage (C-V) measurements on MOS capacitors and current-voltage (I-V) measurements on Schottky barriers. A simple interface state model cannot explain the observed behavior. Schottky barrier measurements made on surfaces which were previously anodized with the oxide layer subsequently removed by etching show evidence for the presence of a compensated layer in the

S. Varadarajan; M. A. Littlejohn; J. R. Hauser



An automated shell for management of parametric dispersion/deposition modeling  

SciTech Connect

In 1993, the US Army tasked Argonne National Laboratory to perform a study of chemical agent dispersion and deposition for the Chemical Stockpile Emergency Preparedness Program using an existing Army computer model. The study explored a wide range of situations in terms of six parameters: agent type, quantity released, liquid droplet size, release height, wind speed, and atmospheric stability. A number of discrete values of interest were chosen for each parameter resulting in a total of 18,144 possible different combinations of parameter values. Therefore, the need arose for a systematic method to assemble the large number of input streams for the model, filter out unrealistic combinations of parameter values, run the model, and extract the results of interest from the extensive model output. To meet these needs, we designed an automated shell for the computer model. The shell processed the inputs, ran the model, and reported the results of interest. By doing so, the shell compressed the time needed to perform the study and freed the researchers to focus on the evaluation and interpretation of the model predictions. The results of the study are still under review by the Army and other agencies; therefore, it would be premature to discuss the results in this paper. However, the design of the shell could be applied to other hazards for which multiple-parameter modeling is performed. This paper describes the design and operation of the shell as an example for other hazards and models.

Paddock, R.A.; Absil, M.J.G.; Peerenboom, J.P.; Newsom, D.E.; North, M.J.; Coskey, R.J. Jr.



Using attributed event grammar environment models for automated test generation and software risk assessment of system-of-systems  

Microsoft Academic Search

This paper presents some concepts, principles, and techniques for automated testing of system-of-systems based on attributed event grammar (AEG) modeling of the system's operational environment. AEG provides a uniform approach for automatically generating, executing, and analyzing tests. Quantitative and qualitative software risk assessment can be performed based on statistics gathered during automatic test execution within the specified environment model.

Mikhail Auguston; James Bret Michael; Man-Tak Shing; David L. Floodeen



Modelling of mass-transfer induced instabilities at liquid-liquid interfaces based on molecular simulations  

NASA Astrophysics Data System (ADS)

Interfaces and especially mass transfer across interfaces are of great importance in many fields of chemical engineering. Interfacial convection, which is generally called the Marangoni effect, may improve mass transfer across interfaces quite drastically and has not been investigated adequately in detail. In order to investigate the influence of mass transfer on a liquid-liquid interface molecular computer simulations have been performed. Since many molecules have to be considered for a significant modelling of the interface, cubic lattice systems have been chosen for the simulation which proceeds according to the Monte-Carlo scheme. The parameters that describe the thermodynamic and transport properties resemble those of realistic standard EFCE test systems for extraction. Results of various Monte-Carlo simulations show that under certain conditions mass transfer across interfaces induces the formation of nano droplets in the close vicinity of the interface. The different combinations of the nano droplet behaviour due to attractive or repulsive long-range forces together with the characteristics of coalescence may lead to different macroscopic interfacial instabilities such as spontaneous emulsification or eruptions. Based on diffusive and thermodynamic properties of the chosen lattice system a first stability criterion which allows the prediction of the onset of nano droplet formation is developed. The theoretical results compare well with experimental observations at a single drop and in a two-phase cell where the instabilities are investigated optically via Schlieren optics.

Schott, Robin; Pfennig, Andreas


Mathematical modeling of the interaction between an insoluble solid particle and a solidifying interface  

NASA Astrophysics Data System (ADS)

When a moving solidification front intercepts an insoluble particle, three distinct interaction phenomena can occur: instantaneous engulfment, continuous pushing of the particle, or particle pushing followed by engulfment. Various mathematical models, aiming to predict the critical solidification velocity for the pushing/engulfment transition, have been published in the literature. However, their predictions were not confirmed by the recent experimental measurements performed in microgravity conditions. The aim of this dissertation is to further continue the study of the interaction particle/solidifying interface through mathematical modeling. In this respect, two new analytical models were developed. In addition, a finite difference numerical approach is proposed. The first analytical model, the Equilibrium Breakdown Model, reveals the fact that the particle/solidifying interface interaction is not a steady state process, as assumed in the previously published models. Its simple formulation makes it attractive for practical purposes such as manufacturing of composite materials. The second model, i.e., the Dynamic Model, is more complex and, for the first time, it is able to capture and explain interesting phenomena that escaped the steady state analyses of previously published models. It shows that steady state interaction is only a particular case that can occur only at sub-critical solidification velocity. In this work, both analytical models were successfully validated against experimental data produced under microgravity conditions. The numerical approach, based on an interface tracking procedure, consists in the development of two distinct models, i.e., a solidification model and a fluid flow model. These two models together can give a more comprehensive picture of the particle/interface interaction. The solidification model has the capability to accommodate changes of the solid/liquid interface temperature because of capillarity and solute redistribution. It is also able to describe changes of the interface shape and the development of the segregation regions in the vicinity of insoluble particles. The purpose of the fluid flow model is to calculate the drag force acting on the particle as it is pushed by an arbitrarily shaped solid/liquid interface. A rigorous analysis performed in this work showed that the real drag force is higher than that calculated with previously published steady state models.

Catalina, Adrian Vasile


Thermal modeling of roll and strip interfaces in rolling processes. Part 2: Simulation  

SciTech Connect

Part 1 of this paper reviewed the modeling approaches and correlations used to study the interface heat transfer phenomena of the roll-strip contact region in rolling processes. The thermal contact conductance approach was recommended for modeling the interface phenomena. To illustrate, the recommended approach and selected correlations are adopted in the present study for modeling of the roll-strip interface region. The specific values of the parameters used to correlate the corresponding thermal contact conductance for the typical cold and hot rolling of steels are first estimated. The influence of thermal contact resistance on the temperature distributions of the roll and strip is then studied. Comparing the present simulation results with previously published experimental and analytical results shows that the thermal contact conductance approach and numerical models used can reliably simulate the heat transfer behavior of the rolling process.

Tseng, A.A. [Arizona State Univ., Tempe, AZ (United States). Mfg. Inst.




SciTech Connect

This paper describes an automated Channel Morphology Tool (CMT) developed in ArcGIS 9.1 environment. The CMT creates cross-sections along a stream centerline and uses a digital elevation model (DEM) to create station points with elevations along each of the cross-sections. The generated cross-sections may then be exported into a hydraulic model. Along with the rapid cross-section generation the CMT also eliminates any cross-section overlaps that might occur due to the sinuosity of the channels using the Cross-section Overlap Correction Algorithm (COCoA). The CMT was tested by extracting cross-sections from a 5-m DEM for a 50-km channel length in Houston, Texas. The extracted cross-sections were compared directly with surveyed cross-sections in terms of the cross-section area. Results indicated that the CMT-generated cross-sections satisfactorily matched the surveyed data.

JUDI, DAVID [Los Alamos National Laboratory; KALYANAPU, ALFRED [Los Alamos National Laboratory; MCPHERSON, TIMOTHY [Los Alamos National Laboratory; BERSCHEID, ALAN [Los Alamos National Laboratory



Patient-specific modelling of the foot: automated hexahedral meshing of the bones.  


Subject-specific finite element modelling is a powerful tool for carrying out controlled investigations of the effects of geometric and material property differences on performance and injury risk. Unfortunately, the creation of suitable meshes for these models is a challenging and time-intensive task. This paper presents an automated method of generating fully hexahedral meshes of the bones of the feet which requires only surface representations as inputs. The method is outlined and example meshes, using two human feet and the foot of a Japanese macaque, are given to demonstrate its flexibility. Mesh quality is also evaluated for the calcaneus, first metatarsal, navicular and talus. Streamlining the generation of finite element meshes of the foot will ease investigations into the patient-specific biomechanics of injury. PMID:22436002

Lievers, W B; Kent, R W



Local nonequilibrium solute trapping model for non-planar interface  

NASA Astrophysics Data System (ADS)

A generalized solute trapping model was proposed incorporating the dependency on interfacial normal velocity along the dendrite side, as an extension of the continuous growth model modified by Sobolev with the local nonequilibrium diffusion model (LNDM). The present model predicts that the transition to diffusionless solidification is not sharp, but occurs in a range of velocities. Analysis indicates that for local nonequilibrium solute diffusion in bulk liquid the effect of the interfacial normal velocity dependency on solute partitioning is considerable.

Li, Shu; Sobolev, S. L.



Automated optimization and construction of chemometric models based on highly variable raw chromatographic data.  


Direct chemometric interpretation of raw chromatographic data (as opposed to integrated peak tables) has been shown to be advantageous in many circumstances. However, this approach presents two significant challenges: data alignment and feature selection. In order to interpret the data, the time axes must be precisely aligned so that the signal from each analyte is recorded at the same coordinates in the data matrix for each and every analyzed sample. Several alignment approaches exist in the literature and they work well when the samples being aligned are reasonably similar. In cases where the background matrix for a series of samples to be modeled is highly variable, the performance of these approaches suffers. Considering the challenge of feature selection, when the raw data are used each signal at each time is viewed as an individual, independent variable; with the data rates of modern chromatographic systems, this generates hundreds of thousands of candidate variables, or tens of millions of candidate variables if multivariate detectors such as mass spectrometers are utilized. Consequently, an automated approach to identify and select appropriate variables for inclusion in a model is desirable. In this research we present an alignment approach that relies on a series of deuterated alkanes which act as retention anchors for an alignment signal, and couple this with an automated feature selection routine based on our novel cluster resolution metric for the construction of a chemometric model. The model system that we use to demonstrate these approaches is a series of simulated arson debris samples analyzed by passive headspace extraction, GC-MS, and interpreted using partial least squares discriminant analysis (PLS-DA). PMID:21641412

Sinkov, Nikolai A; Johnston, Brandon M; Sandercock, P Mark L; Harynuk, James J



A methodology for model-based development and automated verification of software for aerospace systems  

NASA Astrophysics Data System (ADS)

Today's software for aerospace systems typically is very complex. This is due to the increasing number of features as well as the high demand for safety, reliability, and quality. This complexity also leads to significant higher software development costs. To handle the software complexity, a structured development process is necessary. Additionally, compliance with relevant standards for quality assurance is a mandatory concern. To assure high software quality, techniques for verification are necessary. Besides traditional techniques like testing, automated verification techniques like model checking become more popular. The latter examine the whole state space and, consequently, result in a full test coverage. Nevertheless, despite the obvious advantages, this technique is rarely yet used for the development of aerospace systems. In this paper, we propose a tool-supported methodology for the development and formal verification of safety-critical software in the aerospace domain. The methodology relies on the V-Model and defines a comprehensive work flow for model-based software development as well as automated verification in compliance to the European standard series ECSS-E-ST-40C. Furthermore, our methodology supports the generation and deployment of code. For tool support we use the tool SCADE Suite (Esterel Technology), an integrated design environment that covers all the requirements for our methodology. The SCADE Suite is well established in avionics and defense, rail transportation, energy and heavy equipment industries. For evaluation purposes, we apply our approach to an up-to-date case study of the TET-1 satellite bus. In particular, the attitude and orbit control software is considered. The behavioral models for the subsystem are developed, formally verified, and optimized.

Martin, L.; Schatalov, M.; Hagner, M.; Goltz, U.; Maibaum, O.


Automation in air traffic control  

Microsoft Academic Search

A national Air Traffic Control automation system in the Federal Aviation Administration became a possibility with the advent of third generation computer hardware. By mid 1974, the FAA has implemented radar data processing in major terminals and four air route traffic control centers; within the next year all continental centers and high density terminals will be automated and interfaced. Key

Lynn L. Hink



Dynamic Distribution and Layouting of Model-Based User Interfaces in Smart Environments  

NASA Astrophysics Data System (ADS)

The developments in computer technology in the last decade change the ways of computer utilization. The emerging smart environments make it possible to build ubiquitous applications that assist users during their everyday life, at any time, in any context. But the variety of contexts-of-use (user, platform and environment) makes the development of such ubiquitous applications for smart environments and especially its user interfaces a challenging and time-consuming task. We propose a model-based approach, which allows adapting the user interface at runtime to numerous (also unknown) contexts-of-use. Based on a user interface modelling language, defining the fundamentals and constraints of the user interface, a runtime architecture exploits the description to adapt the user interface to the current context-of-use. The architecture provides automatic distribution and layout algorithms for adapting the applications also to contexts unforeseen at design time. Designers do not specify predefined adaptations for each specific situation, but adaptation constraints and guidelines. Furthermore, users are provided with a meta user interface to influence the adaptations according to their needs. A smart home energy management system serves as running example to illustrate the approach.

Roscher, Dirk; Lehmann, Grzegorz; Schwartze, Veit; Blumendorf, Marco; Albayrak, Sahin


Interface characteristics of carbon nanotube reinforced polymer composites using an advanced pull-out model  

NASA Astrophysics Data System (ADS)

An advanced pull-out model is presented to obtain the interface characteristics of carbon nanotube (CNT) in polymer composite. Since, a part of the CNT/matrix interface near the crack tip is considered to be debonded, there must present adhesive van der Waals (vdW) interaction which is generally presented in the form of Lennard-Jones potential. A separate analytical model is also proposed to account normal cohesive stress caused by the vdW interaction along the debonded CNT/polymer interface. Analytical solutions for axial and interfacial shear stress components are derived in closed form. The analytical result shows that contribution of vdW interaction is very significant and also enhances stress transfer potential of CNT in polymer composite. Parametric studies are also conducted to obtain the influence of key composite factors on bonded and debonded interface. The result reveals that the parameter dependency of interfacial stress transfer is significantly higher in the perfectly bonded interface than that of the debonded interface.

Ahmed, Khondaker Sakil; Keng, Ang Kok



A comparison of optimal MIMO linear and nonlinear models for brain–machine interfaces  

Microsoft Academic Search

The field of brain–machine interfaces requires the estimation of a mapping from spike trains collected in motor cortex areas to the hand kinematics of the behaving animal. This paper presents a systematic investigation of several linear (Wiener filter, LMS adaptive filters, gamma filter, subspace Wiener filters) and nonlinear models (time-delay neural network and local linear switching models) applied to datasets

S-P Kim; J C Sanchez; Y N Rao; D Erdogmus; J M Carmena; M A Lebedev; M A L Nicolelis; J C Principe



A proposal for a general interface between land surface schemes and general circulation models  

Microsoft Academic Search

The aim of this paper is to propose a general interface for coupling general circulation models (GCMs) to land surface schemes (LSS) in order to achieve a plug compatibility between these complex models. As surface parameterizations include more processes, they have moved from being subroutines of GCMs to independent schemes which can also be applied for other purposes. This evolution

J. Polcher; B. McAvaney; P. Viterbo; M.-A. Gaertner; A. Hahmann; J.-F. Mahfouf; J. Noilhan; T. Phillips; A. Pitman; C. A. Schlosser; J.-P. Schulz; B. Timbal; D. Verseghy; Y. Xue



Rethinking Design Process: Using 3D Digital Models as an Interface in Collaborative Session  

ERIC Educational Resources Information Center

|This paper describes a pilot study for an alternative design process by integrating a designer-user collaborative session with digital models. The collaborative session took place in a 3D AutoCAD class for a real world project. The 3D models served as an interface for designer-user collaboration during the design process. Students not only…

Ding, Suining



Dosimetry Modeling for Predicting Radiolytic Production at the Spent Fuel - Water Interface  

SciTech Connect

Modeling of the alpha, beta, and gamma dose from spent fuel as a function of particle size and fuel to water ratio was examined. These doses will be combined with modeling of G values and interactions to determine the concentration of various species formed at the fuel water interface and their affect on dissolution rates.

Miller, William H.; Kline, Amanda J.; Hanson, Brady D.



Proposition of an M-Business Procedure Model for the Development of Mobile User Interfaces  

Microsoft Academic Search

In the design of desktop applications, developers successfully deploy structured software life cycle mod- els to simplify the development process. Applying these models in m-business often does not result in usable software. M-business applications differ from desktop applications mainly in their limited user interface as well as the new mobile and dynamic application con- text. Traditional software life cycle models

Susanne Glissmann; Stefan Smolnik; Ragnar Schierholz; Lutz Kolbe; Walter Brenner



LIANA Model Integration System - architecture, user interface design and application in MOIRA DSS  

Microsoft Academic Search

The LIANA Model Integration System is the shell application supporting model integration and user interface functionality required for the rapid construction and run-time support of the environmental decision support systems (EDSS). Internally it is constructed as the framework of C++ classes and functions covering most common tasks performed by the EDSS (such as managing of and alternative strategies, running of

D. Hofman



Automated home cage assessment shows behavioral changes in a transgenic mouse model of spinocerebellar ataxia type 17.  


Spinocerebellar Ataxia type 17 (SCA17) is an autosomal dominantly inherited, neurodegenerative disease characterized by ataxia, involuntary movements, and dementia. A novel SCA17 mouse model having a 71 polyglutamine repeat expansion in the TATA-binding protein (TBP) has shown age related motor deficit using a classic motor test, yet concomitant weight increase might be a confounding factor for this measurement. In this study we used an automated home cage system to test several motor readouts for this same model to confirm pathological behavior results and evaluate benefits of automated home cage in behavior phenotyping. Our results confirm motor deficits in the Tbp/Q71 mice and present previously unrecognized behavioral characteristics obtained from the automated home cage, indicating its use for high-throughput screening and testing, e.g. of therapeutic compounds. PMID:23665119

Portal, Esteban; Riess, Olaf; Nguyen, Huu Phuc



Control of enterprise interfaces for supply chain enterprise modeling  

SciTech Connect

There is a current trend for manufacturing enterprises in a supply chain of a particular industry to join forces in an attempt to promote efficiencies and improve competitive position. Such alliances occur in the context of specific legal and business agreements such that each enterprise retains a majority of its business and manufacturing information as private and shares other information with its trading partners. Shared information may include enterprise demand projections, capacities, finished goods inventories, and aggregate production schedules. Evidence of the trend toward information sharing includes the recent emphases on vendor-managed inventories, quick response, and Electronic Data Interchange (EDI) standards. The increased competition brought on by the global marketplace is driving industries to consider the advantages of trading partner agreements. Aggregate-level forecasts, supply-chain production smoothing, and aggregate-level inventory policies can reduce holding costs, record-keeping overhead, and lead time in product development. The goal of this research is to orchestrate information exchange among trading partners to allow for aggregate-level analysis to enhance supply chain efficiency. The notion of Enterprise Interface Control (EIC) is introduced as a means of accomplishing this end.

Interrante, L.D. [Sandia National Labs., Albuquerque, NM (United States); Macfarlane, J.F. [Lawrence Berkeley Lab., CA (United States). Information and Computing Sciences Div.



Atomistic modeling of the Au droplet–GaAs interface for size-selective nanowire growth  

NASA Astrophysics Data System (ADS)

Density functional theory calculations within both the local density approximation and the generalized gradient approximation are used to study Au-catalyzed growth under near-equilibrium conditions. We discuss both the chemical equilibrium of a GaAs nanowire with an As2 gas atmosphere and the mechanical equilibrium between the capillary forces at the nanowire tip. For the latter goal, the interface between the gold nanoparticle and the nanowire is modeled atomically within a slab approach, and the interface energies are evaluated from the total energies of the model systems. We discuss three growth regimes, one catalyzed by an (almost) pure Au particle, an intermediate alloy-catalyzed growth regime, and a Ga-catalyzed growth regime. Using the interface energies calculated from the atomic models, as well as the surface energies of the nanoparticle and the nanowire sidewalls, we determine the optimized geometry of the nanoparticle-capped nanowire by minimizing the free energy of a continuum model. Under typical experimental conditions of 10?4 Pa As2 and 700 K, our results in the local density approximation are insensitive to the Ga concentration in the nanoparticle. In these growth conditions, the energetically most favored interface has an interface energy of around 45 meV/Å2, and the correspondingly optimized droplet on top of a GaAs nanowire is somewhat larger than a hemisphere and forms a contact angle around 130? for both pure Au and Au-Ga alloy nanoparticles.

Sakong, Sung; Du, Yaojun A.; Kratzer, Peter



An Improved Cochlea Model with a General User Interface  

NASA Astrophysics Data System (ADS)

We have developed a flexible 1D cochlea model to test hypotheses and data against physical and mathematical constraints. The model is flexible in the sense that several linear and nonlinear model characteristics can be selected, and different boundary conditions can be tested. The software model runs at a reasonable speed at a modern PC. As an example, we will show the results of the model in comparison with the systematic study of the phase behavior (group delay) of distortion product otoacoustic emissions (DPOAEs) in the guinea pig (S. Schneider, V. Prijs and R. Schoonhoven, [9]). We also will demonstrate the effects of some common non-physical boundary conditions. Finally, we briefly indicate that this model of the auditory periphery provides a superior front end for an ASR (automatic speech recognition)-system.

Duifhuis, H.; Kruseman, J. M.; van Hengel, P. W. J.



A 3-D Graphical User Interface for Resonance Modeling  

Microsoft Academic Search

Resonance models describe a wide variety of musical sounds using perceptually-meaningful parameters. The compact representation of resonance models allows efficient storage, modification and real-time implementation. Widespread adoption of resonance models has been hampered by the lack of specialized tools to display and manipulate them. We demonstrate here a novel 3D editor designed for musicians, composers and sound designers to manipulate

A. Chaudhary; A. Freed; S. Khoury



Interface reduction of flexible bodies for efficient modeling of body flexibility in multibody dynamics  

Microsoft Academic Search

The floating frame of reference techniques is an established technique to incorporate flexibility in multibody models. The\\u000a model dimension of the body flexibility models can be reduced by model reduction techniques such as Component Mode Synthesis\\u000a (CMS) or Krylov subspace-based techniques, but the efficiency of these techniques is limited by the number of interface nodes\\u000a in which the flexible body

Gert H. K. Heirman; Wim Desmet



Developing and Testing an Integrative Model of the Work–Family Interface  

Microsoft Academic Search

An integrative model of the work–family interface was developed and tested. This model extends prior work by Frone, Russell, and Cooper (1992a). Although the present model adopts the distinction between work-to-family and family-to-work conflict, several important changes have been incorporated. First, a more explicit attempt is made to model the reciprocal (i.e., feedback) relations between work and family life. Second,

Michael R. Frone; John K. Yardley; Karen S. Markel



Examining Uncertainty in Demand Response Baseline Models and Variability in Automated Response to Dynamic Pricing  

SciTech Connect

Controlling electric loads to deliver power system services presents a number of interesting challenges. For example, changes in electricity consumption of Commercial and Industrial (C&I) facilities are usually estimated using counterfactual baseline models, and model uncertainty makes it difficult to precisely quantify control responsiveness. Moreover, C&I facilities exhibit variability in their response. This paper seeks to understand baseline model error and demand-side variability in responses to open-loop control signals (i.e. dynamic prices). Using a regression-based baseline model, we define several Demand Response (DR) parameters, which characterize changes in electricity use on DR days, and then present a method for computing the error associated with DR parameter estimates. In addition to analyzing the magnitude of DR parameter error, we develop a metric to determine how much observed DR parameter variability is attributable to real event-to-event variability versus simply baseline model error. Using data from 38 C&I facilities that participated in an automated DR program in California, we find that DR parameter errors are large. For most facilities, observed DR parameter variability is likely explained by baseline model error, not real DR parameter variability; however, a number of facilities exhibit real DR parameter variability. In some cases, the aggregate population of C&I facilities exhibits real DR parameter variability, resulting in implications for the system operator with respect to both resource planning and system stability.

Mathieu, Johanna L.; Callaway, Duncan S.; Kiliccote, Sila



Mesoscale modeling of the water liquid-vapor interface: A surface tension calculation  

NASA Astrophysics Data System (ADS)

We report a mesoscale modeling of the liquid-vapor interface of water. A mesoscopic model of water has been established in dissipative particle dynamics (DPD) to reproduce the interfacial properties of water. The surface tension and coexisting densities are compared between atomistic and mesoscopic simulations. Simple scaling relations have been established to link the atomistic and mesoscopic length and time scales. Our study demonstrates the capability of the DPD method to explore the interfacial properties of a planar water liquid-vapor interface and a water nanodroplet. This constitutes an important step toward the calculation of the surface tension of larger and more complex interfacial systems.

Ghoufi, A.; Malfreyt, P.



Delft FEWS: an open interface that connects models and data streams for operational forecasting systems  

NASA Astrophysics Data System (ADS)

Many of the operational forecasting systems that are in use today are centred around a single modelling suite. Over the years these systems and the required data streams have been tailored to provide a closed-knit interaction with their underlying modelling components. However, as time progresses it becomes a challenge to integrate new technologies into these model centric operational systems. Often the software used to develop these systems is out of date, or the original designers of these systems are no longer available. Additionally, the changing of the underlying models may requiring the complete system to be changed. This then becomes an extensive effort, not only from a software engineering point of view, but also from a training point of view. Due to significant time and resources being committed to re-training the forecasting teams that interact with the system on a daily basis. One approach to reducing the effort required in integrating new models and data is through an open interface architecture, and through the use of defined interfaces and standards in data exchange. This approach is taken by the Delft-FEWS operational forecasting shell, which has now been applied in some 40 operational forecasting centres across the world. The Delft-FEWS framework provides several interfaces that allow models and data in differing formats to be flexibly integrated with the system. The most common approach to the integration of modes is through the Delft-FEWS Published Interface. This is an XML based data exchange format that supports the exchange of time series data, as well as vector and gridded data formats. The Published Interface supports standardised data formats such as GRIB and the NetCDF-CF standard. A wide range of models has been integrated with the system through this approach, and these are used operationally across the forecasting centres using Delft FEWS. Models can communicate directly with the interface of Delft-FEWS, or through a SOAP service. This giving the flexibility required for a state-of-the-art operational forecasting service. While Delft-FEWS comes with a user-friendly GIS based interface, a time series viewer and editor, and a wide range of tools for visualization, analysis, validation and data conversion, the available graphical display can be extended. New graphical components can be seamlessly integrated with the system through the SOAP service. Thanks to this open infrastructure, new models can easily be incorporated into an operational system without having to change the operational process. This allows the forecaster to focus on the science instead of having to worry about model details and data formats. Furthermore all model formats introduced to the Delft-FEWS framework will in principle become available to the Delft-FEWS community (in some cases subject to the licence conditions of the model supplier). Currently a wide range of models has been integrated and is being used operationally; Mike 11, HEC-RAS & HEC-RESSIM, HBV, MODFLOW, SOBEK and more. In this way Delft-FEWS not only provides a modelling interface but also a platform for model inter-comparison or multi-model ensembles, as well as a knowledge interface that allows forecasters throughout the world to exchange their views and ideas on operational forecasting. Keywords: FEWS; forecasting; modelling; timeseries; data; XML; NetCDF; interface; SOAP

de Rooij, Erik; Werner, Micha



The interface response function and melting point of the prism interface of ice I h using a fluctuating charge model (TIP4P-FQ)  

Microsoft Academic Search

Molecular Dynamics simulations have been used to follow the rate of growth and recession of the prismatic surface of a hexagonal ice–water interface. The fluctuating charge, four-site transferable intermolecular potential model, TIP4P-FQ, was used at temperatures between 265 and 310K in a series of isobaric isothermal (NPT) Molecular Dynamics simulations. Using appropriate order parameters, an interface response function (IRF) that

Benjamin F. Nicholson; Paulette Clancy; Steven W. Rick



The interface response function and melting point of the prism interface of ice Ih using a fluctuating charge model (TIP4P-FQ)  

Microsoft Academic Search

Molecular Dynamics simulations have been used to follow the rate of growth and recession of the prismatic surface of a hexagonal ice water interface. The fluctuating charge, four-site transferable intermolecular potential model, TIP4P-FQ, was used at temperatures between 265 and 310 K in a series of isobaric isothermal (NPT) Molecular Dynamics simulations. Using appropriate order parameters, an interface response function

Benjamin F. Nicholson; Paulette Clancy; Steven W. Rick



A model for investigating the behaviour of non-spherical particles at interfaces.  


This paper introduces a simple method for modelling non-spherical particles with a fixed contact angle at an interface whilst also providing a method to fix the particles orientation. It is shown how a wide variety of particle shapes (spherical, ellipsoidal, disc) can be created from a simple initial geometry containing only six vertices. The shapes are made from one continuous surface with edges and corners treated as smooth curves not discontinuities. As such, particles approaching cylindrical and orthorhombic shapes can be simulated but the contact angle crossing the edges will be fixed. Non-spherical particles, when attached to an interface can cause large distortions in the surface which affect the forces acting on the particle. The model presented is capable of resolving this distortion of the surface around the particle at the interface as well as allowing for the particle's orientation to be controlled. It is shown that, when considering orthorhombic particles with rounded edges, the flatter the particle the more energetically stable it is to sit flat at the interface. However, as the particle becomes more cube like, the effects of contact angle have a greater effect on the energetically stable orientations. Results for cylindrical particles with rounded edges are also discussed. The model presented allows the user to define the shape, dimensions, contact angle and orientation of the particle at the interface allowing more in-depth investigation of the complex phenomenon of 3D film distortion around an attached particle and the forces that arise due to it. PMID:21067767

Morris, G; Neethling, S J; Cilliers, J J



An automated approach for segmentation of intravascular ultrasound images based on parametric active contour models.  


This paper presents a fully automated approach to detect the intima and media-adventitia borders in intravascular ultrasound images based on parametric active contour models. To detect the intima border, we compute a new image feature applying a combination of short-term autocorrelations calculated for the contour pixels. These feature values are employed to define an energy function of the active contour called normalized cumulative short-term autocorrelation. Exploiting this energy function, the intima border is separated accurately from the blood region contaminated by high speckle noise. To extract media-adventitia boundary, we define a new form of energy function based on edge, texture and spring forces for the active contour. Utilizing this active contour, the media-adventitia border is identified correctly even in presence of branch openings and calcifications. Experimental results indicate accuracy of the proposed methods. In addition, statistical analysis demonstrates high conformity between manual tracing and the results obtained by the proposed approaches. PMID:22415899

Vard, Alireza; Jamshidi, Kamal; Movahhedinia, Naser



Sloan Digital Sky Survey photometric telescope automation and observing software  

NASA Astrophysics Data System (ADS)

The photometric telescope (PT) provides observations necessary for the photometric calibration of the Sloan Digital Sky Survey (SDSS). Because the attention of the observing staff is occupied by the operation of the 2.5 meter telescope which takes the survey data proper, the PT must reliably take data with little supervision. In this paper we describe the PT's observing program, MOP, which automates most tasks necessary for observing. MOP's automated target selection is closely modeled on the actions a human observer might take, and is built upon a user interface that can be (and has been) used for manual operation. This results in an interface that makes it easy for an observer to track the activities of the automating procedures and intervene with minimum disturbance when necessary. MOP selects targets from the same list of standard star and calibration fields presented to the user, and chooses standard star fields covering ranges of airmass, color, and time necessary to monitor atmospheric extinction and produce a photometric solution. The software determines when additional standard star fields are unnecessary, and selects survey calibration fields according to availability and priority. Other automated features of MOP, such as maintaining the focus and keeping a night log, are also built around still functional manual interfaces, allowing the observer to be as active in observing as desired; MOP's automated features may be used as tools for manual observing, ignored entirely, or allowed to run the telescope with minimal supervision when taking routine data.

Neilsen, Eric H., Jr.; Uomoto, Alan; Kent, Steven M.; Annis, James T.



A graphical user interface for numerical modeling of acclimation responses of vegetation to climate change  

NASA Astrophysics Data System (ADS)

Ecophysiological models that vertically resolve vegetation canopy states are becoming a powerful tool for studying the exchange of mass, energy, and momentum between the land surface and the atmosphere. A mechanistic multilayer canopy-soil-root system model (MLCan) developed by Drewry et al. (2010a) has been used to capture the emergent vegetation responses to elevated atmospheric CO2 for both C3 and C4 plants under various climate conditions. However, processing input data and setting up such a model can be time-consuming and error-prone. In this paper, a graphical user interface that has been developed for MLCan is presented. The design of this interface aims to provide visualization capabilities and interactive support for processing input meteorological forcing data and vegetation parameter values to facilitate the use of this model. In addition, the interface also provides graphical tools for analyzing the forcing data and simulated numerical results. The model and its interface are both written in the MATLAB programming language. Finally, an application of this model package for capturing the ecohydrological responses of three bioenergy crops (maize, miscanthus, and switchgrass) to local environmental drivers at two different sites in the Midwestern United States is presented.

Le, Phong V. V.; Kumar, Praveen; Drewry, Darren T.; Quijano, Juan C.



Mechanically mediated electron transfer in model metallo-enzyme interfaces  

Microsoft Academic Search

In this paper, we develop a physical analysis of charge transfer in the model ‘metallo-enzyme’ complex which consists of a synthetic redox-addressed assembly (a ‘reaction center’) hybridized with a quantum dot (a gold nanoparticle) and attached via molecular bridge (a spacer) to the electrode. This artificial system allows us to model electronic transduction in experimental redox ezyme-gold nanoparticle hybrid structure

L. Yu. Gorelik; M. V. Voinova



Scale-coupling and interface-pinning effects in the phase-field-crystal model.  


Effects of scale coupling between mesoscopic slowly varying envelopes of liquid-solid profile and the underlying microscopic crystalline structure are studied in the phase-field-crystal (PFC) model. Such scale coupling leads to nonadiabatic corrections to the PFC amplitude equations, the effect of which increases strongly with decreasing system temperature below the melting point. This nonadiabatic amplitude representation is further coarse-grained for the derivation of effective sharp-interface equations of motion in the limit of small but finite interface thickness. We identify a generalized form of the Gibbs-Thomson relation with the incorporation of coupling and pinning effects of the crystalline lattice structure. This generalized interface equation can be reduced to the form of a driven sine-Gordon equation with Kardar-Parisi-Zhang (KPZ) nonlinearity, and can be combined with two other dynamic equations in the sharp interface limit obeying the conservation condition of atomic number density in a liquid-solid system. A sample application to the study of crystal layer growth is given, and the corresponding analytic solutions showing lattice pinning and depinning effects and two distinct modes of continuous vs nucleated growth are presented. We also identify the universal scaling behaviors governing the properties of pinning strength, surface tension, interface kinetic coefficient, and activation energy of atomic layer growth, which accommodate all range of liquid-solid interface thicknesses and different material elastic moduli. PMID:23410338

Huang, Zhi-Feng



Automated Geospatial Watershed Assessment  

EPA Science Inventory

The Automated Geospatial Watershed Assessment (AGWA) tool is a Geographic Information Systems (GIS) interface jointly developed by the U.S. Environmental Protection Agency, the U.S. Department of Agriculture (USDA) Agricultural Research Service, and the University of Arizona to a...


Automated Tissue Classiflcation of noisy MR Images of the Brain Using Constrained Multiple Multivariate Gaussian Mixture Model (CGMM)  

Microsoft Academic Search

We present a fully automated algorithm for tissue segmentation of noisy, low con- trast magnetic resonance (MR) images of the brain. We use a mixture model composed of a large number of Gaussians to represent the brain image. Each tissue is represented by a large number of the Gaussian components in order to capture the complex tissue spatial layout. The

Amit Ruf; Hayit Greenspan


Photometric model of diffuse surfaces described as a distribution of interfaced Lambertian facets.  


The Lambertian model for diffuse reflection is widely used for the sake of its simplicity. Nevertheless, this model is known to be inaccurate in describing a lot of real-world objects, including those that present a matte surface. To overcome this difficulty, we propose a photometric model where the surfaces are described as a distribution of facets where each facet consists of a flat interface on a Lambertian background. Compared to the Lambertian model, it includes two additional physical parameters: an interface roughness parameter and the ratio between the refractive indices of the background binder and of the upper medium. The Torrance-Sparrow model--distribution of strictly specular facets--and the Oren-Nayar model--distribution of strictly Lambertian facets--appear as special cases. PMID:19844317

Simonot, Lionel



Laboratory measurements and theoretical modeling of seismoelectric interface response and coseismic wave fields  

SciTech Connect

A full-waveform seismoelectric numerical model incorporating the directivity pattern of a pressure source is developed. This model provides predictions of coseismic electric fields and the electromagnetic waves that originate from a fluid/porous-medium interface. An experimental setup in which coseismic electric fields and interface responses are measured is constructed. The seismo-electric origin of the signals is confirmed. The numerically predicted polarity reversal of the interfacial signal and seismoelectric effects due to multiple scattering are detected in the measurements. Both the simulated coseismic electric fields and the electromagnetic waves originating from interfaces agree with the measurements in terms of travel times, waveform, polarity, amplitude, and spatial amplitude decay, demonstrating that seismoelectric effects are comprehensively described by theory.

Schakel, M. D.; Slob, E. C.; Heller, H. K. J. [Department of Geotechnology, Delft University of Technology, PO Box 5048, 2600 GA, Delft (Netherlands); Smeulders, D. M. J. [Department of Geotechnology, Delft University of Technology, PO Box 5048, 2600 GA, Delft (Netherlands); Department of Mechanical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB, Eindhoven (Netherlands)



Models for ultrasonic characterization of environmental degradation of interfaces in adhesive joints  

SciTech Connect

In this paper we discuss two models of environmental degradation of adhesive joints developed from experimental observation of the joint failure mode. It is found that after severe degradation, failure is dominated by the interfacial mode, i.e., by failure at the interface between adhesive and adherend. The fraction of failure in the interfacial mode was found to be related to the joint strength and to be proportional to the frequency shift of a minimum in the spectrum of the reflected ultrasonic signal. One model considers an interface as an interphase in the form of a nonhomogeneous layer composed of two phases: soft'' which is viscoelastic (degraded part of the interphase) and stiff'' corresponding to the nondamaged interphase. Increase of the soft'' phase fraction corresponds to the process of degradation in the interphase. The second model describes degradation in a form of disbonds filled by absorbed water at the interface. The disbonded interface is modeled by transverse spring boundary conditions, with the complex spring stiffness representing the quality of the bond. The influence of different disbond growth scenarios is considered. Advantages and drawbacks of these models are discussed.

Lavrentyev, A.I.; Rokhlin, S.I. (Nondestructive Evaluation Program, The Ohio State University, 190 West 19th Avenue, Columbus, Ohio 43210 (United States))



Rich Interfaces for Dependability: Compositional Methods for Dynamic Fault Trees and Arcade models  

Microsoft Academic Search

This paper discusses two behavioural interfaces for reliability\\u000aanalysis: dynamic fault trees, which model the system\\u000areliability in terms of the reliability of its components\\u000aand Arcade, which models the system reliability at an architectural\\u000alevel. For both formalisms, the reliability is analyzed\\u000aby transforming the DFT or Arcade model to a set\\u000aof input-output Markov Chains. By using compositional

Hichem Boudali; Pepijn Crouzen; Boudewijn R. Haverkort; Matthias Kuntz; Mariëlle Stoelinga



Learning in Closed-Loop Brain-Machine Interfaces: Modeling and Experimental Validation  

Microsoft Academic Search

Closed-loop operation of a brain-machine interface (BMI) relies on the subject's ability to learn an inverse transformation of the plant to be controlled. In this paper, we propose a model of the learning process that undergoes closed-loop BMI operation. We first explore the properties of the model and show that it is able to learn an inverse model of the

Rodolphe Héliot; Karunesh Ganguly; Jessica Jimenez; Jose M. Carmena



Geometrical models of interface evolution. III. Theory of dendritic growth  

Microsoft Academic Search

We construct a theory of velocity selection and tip stability for dendritic growth in the local evolution model. We show that the growth rate of dendritic patterns is determined by a nonlinear solvability condition for a translating finger. The sidebranching instability is related to a single discrete oscillatory mode about the selected velocity solution, and the existence of a critical

David A. Kessler; Joel Koplik; Herbert Levine



Model-Based User-Interface Management for Public Services  

Microsoft Academic Search

Public business processes can be very complex. That makes it hard for citizens to understand these processes and for software companies to implement them into software tools. Changes of the process entail expensive effort in both teaching the citizens and adapting the software. For business processes several model-based approaches have been suggested to deal with high complexity, such as BPMN.

Jörn Freiheit; Fabrice A. Zangl


Matrix and Interface Stresses in a Discontinuous Fiber Composite Model  

Microsoft Academic Search

The method of finite element analysis is applied to an axially symmetrical model of a single filament glass-resin composite under tension. Fiber end geometries are varied by considering ellipsoids of revolution with one axis length equal to the fiber diameter while the second varies from one-tenth to ten times the fiber diameter. Tapered tips with these same axis ratios are

Anthony S. Carrara; Frederick J. Mcgarry



Automated method for modeling seven-helix transmembrane receptors from experimental data.  

PubMed Central

A rule-based automated method is presented for modeling the structures of the seven transmembrane helices of G-protein-coupled receptors. The structures are generated by using a simulated annealing Monte Carlo procedure that positions and orients rigid helices to satisfy structural restraints. The restraints are derived from analysis of experimental information from biophysical studies on native and mutant proteins, from analysis of the sequences of related proteins, and from theoretical considerations of protein structure. Calculations are presented for two systems. The method was validated through calculations using appropriate experimental information for bacteriorhodopsin, which produced a model structure with a root mean square (rms) deviation of 1.87 A from the structure determined by electron microscopy. Calculations are also presented using experimental and theoretical information available for bovine rhodopsin to assign the helices to a projection density map and to produce a model of bovine rhodopsin that can be used as a template for modeling other G-protein-coupled receptors. Images FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 8 FIGURE 11

Herzyk, P; Hubbard, R E



Experimental studies on multiple-model predictive control for automated regulation of hemodynamic variables.  


A model-based control methodology was developed for automated regulation of mean arterial pressure and cardiac output in critical care subjects using inotropic and vasoactive drugs. The control algorithm used a multiple-model adaptive approach in a model predictive control framework to account for variability and explicitly handle drug rate constraints. The controller was experimentally evaluated on canines that were pharmacologically altered to exhibit symptoms of hypertension and depressed cardiac output. The controller performed better as compared to experiments on manual regulation of the hemodynamic variables. After the model bank was determined, mean arterial pressure was held within +/- 5 mm Hg 88.9% of the time with a standard deviation of 3.9 mm Hg. The cardiac output was held within +/- 1 l/min 96.1% of the time with a standard deviation of 0.5 l/min. The manual runs maintain mean arterial pressure only 82.3% of the time with a standard deviation of 5 mm Hg, and cardiac output 92.2% of the time with a standard deviation of 0.6 l/min. PMID:12669984

Rao, Ramesh R; Aufderheide, Brian; Bequette, B Wayne



Development and Implementation of an Extensible Interface-Based Spatiotemporal Geoprocessing and Modeling Toolbox  

NASA Astrophysics Data System (ADS)

This poster presents an object oriented and interface-based spatiotemporal data processing and modeling toolbox that can be extended by third parties to include complete suites of new tools through the implementation of simple interfaces. The resulting software implementation includes both a toolbox and workflow designer or "model builder" constructed using the underlying open source DotSpatial library and MapWindow desktop GIS. The unique contribution of this research and software development activity is in the creation and use of an extensibility architecture for both specific tools (through a so-called "ITool" interface) and batches of tools (through a so-called "IToolProvider" interface.) This concept is introduced to allow for seamless integration of geoprocessing tools from various sources (e.g. distinct libraries of spatiotemporal processing code) - including online sources - within a single user environment. In this way, the IToolProvider interface allows developers to wrap large existing collections of data analysis code without having to re-write it for interoperability. Additionally, developers do not need to design the user interfaces for loading, displaying or interacting with their specific tools, but rather can simply implement the provided interfaces and have their tools and tool collections appear in the toolbox alongside other tools. The demonstration software presented here is based on an implementation of the interfaces and sample tool libraries using the C# .NET programming language. This poster will include a summary of the interfaces as well as a demonstration of the system using the Whitebox Geospatial Analysis Tools (GAT) as an example case of a large number of existing tools that can be exposed to users through this new system. Vector analysis tools which are native in DotSpatial are linked to the Whitebox raster analysis tools in the model builder environment for ease of execution and consistent/repeatable use. We expect that this approach to development of spatiotemporal analysis and geoprocessing software can be extended to many areas including basic GIS analysis, hydrological and terrain analysis, or processing images and working with LiDAR data.

Cao, Y.; Ames, D. P.



Modeling Nitrogen Cycle at the Surface-Subsurface Water Interface  

NASA Astrophysics Data System (ADS)

Anthropogenic activities, primarily food and energy production, have altered the global nitrogen cycle, increasing reactive dissolved inorganic nitrogen, Nr, chiefly ammonium NH4+ and nitrate NO3-, availability in many streams worldwide. Increased Nr promotes biological activity often with negative consequences such as water body eutrophication and emission of nitrous oxide gas, N2O, an important greenhouse gas as a by-product of denitrification. The hyporheic zone may play an important role in processing Nr and returning it to the atmosphere. Here, we present a process-based three-dimensional semi-analytical model, which couples hyporheic hydraulics with biogeochemical reactions and transport equations. Transport is solved by means of particle tracking with negligible local dispersion and biogeochemical reactions modeled by linearized Monod's kinetics with temperature dependant reaction rate coefficients. Comparison of measured and predicted N2O emissions from 7 natural stream shows a good match. We apply our model to gravel bed rivers with alternate bar morphology to investigate the role of hyporheic hydraulic, depth of alluvium, relative availability of stream concentration of NO3- and NH4+ and water temperature on nitrogen gradients within the sediment. Our model shows complex concentration dynamics, which depend on hyporheic residence time distribution and consequently on streambed morphology, within the hyporheic zone. Nitrogen gas emissions from the hyporheic zone increase with alluvium depth in large low-gradient streams but not in small steep streams. On the other hand, hyporheic water temperature influences nitrification/denitrification processes mainly in small-steep than large low-gradient streams, because of the long residence times, which offset the slow reaction rates induced by low temperatures in the latter stream. The overall conclusion of our analysis is that river morphology has a major impact on biogeochemical processes such as nitrification and denitrification with a direct impact on the stream nutrient removal and transport.

Marzadri, A.; Tonina, D.; Bellin, A.



Model studies of Rayleigh instabilities via microdesigned interfaces  

SciTech Connect

The energetic and kinetic properties of surfaces play a critical role in defining the microstructural changes that occur during sintering and high-temperature use of ceramics. Characterization of surface diffusion in ceramics is particularly difficult, and significant variations in reported values of surface diffusivities arise even in well-studied systems. Effects of impurities, surface energy anisotropy, and the onset of surface attachment limited kinetics (SALK) are believed to contribute to this variability. An overview of the use of Rayleigh instabilities as a means of characterizing surface diffusivities is presented. The development of models of morphological evolution that account for effects of surface energy anisotropy is reviewed, and the potential interplay between impurities and surface energy anisotropy is addressed. The status of experimental studies of Rayleigh instabilities in sapphire utilizing lithographically introduced pore channels of controlled geometry and crystallography is summarized. Results of model studies indicate that impurities can significantly influence both the spatial and temporal characteristics of Rayleigh instabilities; this is attributed at least in part to impurity effects on the surface energy anisotropy. Related model experiments indicate that the onset of SALK may also contribute significantly to apparent variations in surface diffusion coefficients.

Glaeser, Andreas M.



Automated rodent in situ muscle contraction assay and myofiber organization analysis in sarcopenia animal models.  


Age-related sarcopenia results in frailty and decreased mobility, which are associated with increased falls and long-term disability in the elderly. Given the global increase in lifespan, sarcopenia is a growing, unmet medical need. This report aims to systematically characterize muscle aging in preclinical models, which may facilitate the development of sarcopenia therapies. Naïve rats and mice were subjected to noninvasive micro X-ray computed tomography (micro-CT) imaging, terminal in situ muscle function characterizations, and ATPase-based myofiber analysis. We developed a Definiens (Parsippany, NJ)-based algorithm to automate micro-CT image analysis, which facilitates longitudinal in vivo muscle mass analysis. We report development and characterization of translational in situ skeletal muscle performance assay systems in rat and mouse. The systems incorporate a custom-designed animal assay stage, resulting in enhanced force measurement precision, and LabVIEW (National Instruments, Austin, TX)-based algorithms to support automated data acquisition and data analysis. We used ATPase-staining techniques for myofibers to characterize fiber subtypes and distribution. Major parameters contributing to muscle performance were identified using data mining and integration, enabled by Labmatrix (BioFortis, Columbia, MD). These technologies enabled the systemic and accurate monitoring of muscle aging from a large number of animals. The data indicated that longitudinal muscle cross-sectional area measurement effectively monitors change of muscle mass and function during aging. Furthermore, the data showed that muscle performance during aging is also modulated by myofiber remodeling factors, such as changes in myofiber distribution patterns and changes in fiber shape, which affect myofiber interaction. This in vivo muscle assay platform has been applied to support identification and validation of novel targets for the treatment of sarcopenia. PMID:22461442

Weber, H; Rauch, A; Adamski, S; Chakravarthy, K; Kulkarni, A; Dogdas, B; Bendtsen, C; Kath, G; Alves, S E; Wilkinson, H A; Chiu, C-S



Modelling electrified interfaces in quantum chemistry: constant charge vs. constant potential.  


The proper description of electrified metal/solution interfaces, as they occur in electrochemical systems, is a key component for simulating the unique features of electrocatalytic reactions using electronic structure calculations. While in standard solid state (plane wave, periodic boundary conditions) density functional theory (DFT) calculations several models for describing electrochemical environments exist, for cluster models in a quantum chemistry approach (atomic orbital basis, finite system) this is not straightforward. In this work, two different approaches for the theoretical description of electrified interfaces of nanoparticles, the constant charge and the constant potential model, are discussed. Different schemes for describing electrochemical reactions including solvation models are tested for a consistent description of the electrochemical potential and the local chemical behavior for finite structures. The different schemes and models are investigated for the oxygen reduction reaction (ORR) on a hemispherical cuboctahedral platinum nanoparticle. PMID:23329171

Benedikt, Udo; Schneider, Wolfgang B; Auer, Alexander A



Computational modeling and experimental investigation of effects of compositional elements on interface and design aesthetics  

Microsoft Academic Search

This article describes computational modeling and two corresponding experimental investigations of the effects of symmetry, balance and quantity of construction elements on interface aesthetic judgments. In the first experiment, 30 black and white geometric images were developed by systematically varying these three attributes in order to validate computational aesthetic quantification algorithms with subject ratings. The second experiment employed the same

Michael Bauerly; Yili Liu



Relational Grammars: Theory and Practice in a Visual Language Interface for Process Modeling  

Microsoft Academic Search

Relational Grammars (RGs) are one of the higher-dimensional grammar formalisms that have been proposed for representing visual languages (VLs). This paper serves as an overview of the formalism as well as a case study of its application in a visual language interface (VLI) for process model- ing. Relational Grammars are a member of the context-free family of Con- straint Multiset

Kent Wittenburg; Louis Weitzman



Modeling fractures as interfaces for o w and transport in porous media  

Microsoft Academic Search

Fractures in a porous medium are considered individually and are supposed to be a porous medium of higher permeability than in the surrounding rock. Since their thickness is supposed to be small with respect to the dimension of the domain of calculation they are modelled as interfaces. We formulate the o w and the transport in the medium, taking into

Clarisse Alboin; Jean E. Roberts


The integrity of welded interfaces in ultra high molecular weight polyethylene: Part 1-Model.  


The difficulty of eradicating memory of powder-particle interfaces in UHMWPE for bearing surfaces for hip and knee replacements is well-known, and 'fusion defects' have been implicated frequently in joint failures. During processing the polymer is formed into solid directly from the reactor powder, under pressure and at temperatures above the melting point, and two types of inter-particle defect occur: Type 1 (consolidation-deficient) and Type 2 (diffusion-deficient). To gain quantitative information on the extent of the problem, the formation of macroscopic butt welds in this material was studied, by (1) modelling the process and (2) measuring experimentally the resultant evolution of interface toughness. This paper reports on the model. A quantitative measure of interface structural integrity is defined, and related to the "maximum reptated molecular weight" introduced previously. The model assumes an idealised surface topography. It is used to calculate the evolution of interface integrity during welding, for given values of temperature, pressure, and parameters describing the surfaces, and a given molar mass distribution. Only four material properties are needed for the calculation; all of them available for polyethylene. The model shows that, for UHMWPE typically employed in knee transplants, the rate of eradication of Type 1 defects is highly sensitive to surface topography, process temperature and pressure. Also, even if Type 1 defects are prevented, Type 2 defects heal extremely slowly. They must be an intrinsic feature of UHMWPE for all reasonable forming conditions, and products and forming processes should be designed accordingly. PMID:16490249

Buckley, C Paul; Wu, Junjie; Haughie, David W



Programming models and HW-SW interfaces abstraction for multi-processor SoC  

Microsoft Academic Search

For the design of classic computers the Parallel programming concept is used to abstract HW\\/SW interfaces during high level specification of application software. The software is then adapted to existing multiprocessor platforms using a low level software layer that implements the programming model. Unlike classic computers, the design of heterogeneous MPSoC includes also building the processors and other kind of

Ahmed Amine Jerraya; Aimen Bouchhima; Frédéric Pétrot



Quasi-Steady Models for Dynamic Salt-Fresh Interface Analysis.  

National Technical Information Service (NTIS)

Two quasi-steady methods for unsteady analyses of the motion of the salt-fresh interface in unconfined coastal aquifers are invesigated. Their performance is evaluated through comparisons of the results from the quasi-steady models with results from a mor...

L. T. Isaacs



Field evaluation of a cross platform 6 key navigation model and a unified user interface design  

Microsoft Academic Search

Within this paper we present the results from a field study conducted to evaluate a cross platform six key navigation model and its unified user interface for an electronic program guide (EPG) application running on the TV, PC, and mobile phone. The application was evaluated on all three devices with four selected families in their real home environment. Thereby, a

Marianna Obrist; Christiane Moser; Manfred Tscheligi; Damien Alliez



Automated manipulation of systems biology models using libSBML within Taverna workflows  

Microsoft Academic Search

Many data manipulation processes involve the use of programming libraries. These processes may beneficially be automated due to their repeated use. A convenient type of automation is in the form of workflows that also allow such processes to be shared amongst the community. The Taverna workflow system has been extended to enable it to use and invoke Java classes and

Peter Li; Tom Oinn; Stian Soiland; Douglas B. Kell



Semi-automated DIRSIG scene modeling from three-dimensional lidar and passive imagery  

NASA Astrophysics Data System (ADS)

The Digital Imaging and Remote Sensing Image Generation (DIRSIG) model is an established, first-principles based scene simulation tool that produces synthetic multispectral and hyperspectral images from the visible to long wave infrared (0.4 to 20 microns). Over the last few years, significant enhancements such as spectral polarimetric and active Light Detection and Ranging (lidar) models have also been incorporated into the software, providing an extremely powerful tool for multi-sensor algorithm testing and sensor evaluation. However, the extensive time required to create large-scale scenes has limited DIRSIG's ability to generate scenes "on demand." To date, scene generation has been a laborious, time-intensive process, as the terrain model, CAD objects and background maps have to be created and attributed manually. To shorten the time required for this process, this research developed an approach to reduce the man-in-the-loop requirements for several aspects of synthetic scene construction. Through a fusion of 3D lidar data with passive imagery, we were able to semi-automate several of the required tasks in the DIRSIG scene creation process. Additionally, many of the remaining tasks realized a shortened implementation time through this application of multi-modal imagery. Lidar data is exploited to identify ground and object features as well as to define initial tree location and building parameter estimates. These estimates are then refined by analyzing high-resolution frame array imagery using the concepts of projective geometry in lieu of the more common Euclidean approach found in most traditional photogrammetric references. Spectral imagery is also used to assign material characteristics to the modeled geometric objects. This is achieved through a modified atmospheric compensation applied to raw hyperspectral imagery. These techniques have been successfully applied to imagery collected over the RIT campus and the greater Rochester area. The data used include multiple-return point information provided by an Optech lidar linescanning sensor, multispectral frame array imagery from the Wildfire Airborne Sensor Program (WASP) and WASP-lite sensors, and hyperspectral data from the Modular Imaging Spectrometer Instrument (MISI) and the COMPact Airborne Spectral Sensor (COMPASS). Information from these image sources was fused and processed using the semi-automated approach to provide the DIRSIG input files used to define a synthetic scene. When compared to the standard manual process for creating these files, we achieved approximately a tenfold increase in speed, as well as a significant increase in geometric accuracy.

Lach, Stephen R.


Modeling fretting fatigue: interface contact conditions based on profilometry data  

NASA Astrophysics Data System (ADS)

The parameters that govern the life of metallic materials under conditions of fretting fatigue may be divided into two broad categories. The first category deals with the materials properties and characteristics while the second includes the externally imposed loading conditions and contact geometry. The two materials in contact may either stick, slip or stick-clip with each other. It has been shown that the life reduction is highest under partial slip. The objective of the present research effort is focused to the prediction of the particular fretting fatigue regime and hence get an estimate of the life reduction of a particular materials/component. The above may be accomplished by using as input to a specific model, a series of data obtained from non-destructive and other characterization techniques. To this end, the bodies in contact is developed and hence the different materials as well as external parameters which influence the process are identified. Although the external are implied by the should be determined quantitatively. This is accomplished by white light interference profilometry, which was used to characterization were used as input into the model to predict the actual contact conditions. Experimental results concerned with the fatigue life were plotted on the fretting maps; the fretting fatigue regimes indicated by the latter enabled the interpretation of the experimental data.

Nicolaou, Perikles D.; Matikas, Theodore E.; Shell, Eric B.



Terrain accretion along the subduction interface: numerical modeling  

NASA Astrophysics Data System (ADS)

The oceanic floor contains allochthonous terranes (extinct ridges and arcs, continental fragments and volcanic piles) that move with the oceanic crust and may collide with continental margins to form collisional orogens that are believed to have contributed to the growth of the continental crust. The dynamics of terrane accretion and its implcation in relation to crustal growth were analyzed using a thermomechanical-pertological numerical model of an oceanic-continental subduction zone. The model is based on the i2vis code, that solves the govering equations of mass, momentum and energy for a viscous-plastic rheology. Our results indicate that allochthonous terranes may subduct or accrete depending on their rheological strength and the negative buoyancy of the downgoing slab, which is imposed by its thermal structure. Subduction of cold and dense oceanic lithosphere coupled with the collsion of rheologically strong terranes results in deep subdution. Crustal material may be subducted back into the mantle or be incorporated into active arcs that form above the overriding plate. Terranes with a weak crustal structure that are embedded in young oceanic lithosphere are less prone to subdution and may be accreted in form of collisional orogens and accreted terranes. Weak crustal material is scrapped off the downgoing plate and added to the continental margin, which leads to rapid growth of the continental crust and may result in plate failure associated with slab break off. In cases where slab break off occurs a new subduction zone is formed behnind the accreted terrane.

Vogt, K.; Gerya, T.



Towards Automated Bargaining in Electronic Markets: A Partially Two-Sided Competition Model  

NASA Astrophysics Data System (ADS)

This paper focuses on the prominent issue of automating bargaining agents within electronic markets. Models of bargaining in literature deal with settings wherein there are only two agents and no model satisfactorily captures settings in which there is competition among buyers, being they more than one, and analogously among sellers. In this paper, we extend the principal bargaining protocol, i.e. the alternating-offers protocol, to capture bargaining in markets. The model we propose is such that, in presence of a unique buyer and a unique seller, agents' equilibrium strategies are those in the original protocol. Moreover, we game theoretically study the considered game providing the following results: in presence of one-sided competition (more buyers and one seller or vice versa) we provide agents' equilibrium strategies for all the values of the parameters, in presence of two-sided competition (more buyers and more sellers) we provide an algorithm that produce agents' equilibrium strategies for a large set of the parameters and we experimentally evaluate its effectiveness.

Gatti, Nicola; Lazaric, Alessandro; Restelli, Marcello


Automated Probing and Inference of Analytical Models for Metabolic Network Dynamics  

NASA Astrophysics Data System (ADS)

We introduce a method to automatically construct mathematical models of a biological system, and apply this technique to infer a seven-dimensional nonlinear model of glycolytic oscillations in yeast -- based only on noisy observational data obtained from in silico experiments. Graph-based symbolic encoding, fitness prediction, and estimation-exploration can for the first time provide the level of symbolic regression required for biological applications. With no a priori knowledge of the system, the Cornell algorithm in several hours of computation correctly identified all seven ordinary nonlinear differential equations, the most complicated of which was dA3dt=-1.12.A3-192.24.A3S11+12.50.A3^4+124.92.S3+31.69.A3S3, where A3 = [ATP], S1= [glucose], and S3 = [cytosolic pyruvate and acetaldehyde pool]. Errors on the 26 parameters ranged from 0 to 14.5%. The algorithm also automatically identified new and potentially useful chemical constants of the motion, e.g. -k1N2+K2v1+k2S1A3-(k4-k5v1)A3^4+k6 0. This approach may enable automated design, control and analysis of wet-lab experiments for model identification/refinement.

Wikswo, John; Schmidt, Michael; Jenkins, Jerry; Hood, Jonathan; Lipson, Hod



The characterization of a proposed model GaAs\\/anodic oxide interface  

Microsoft Academic Search

The n-GaAs\\/anodic oxide interface has been characterized using capacitance-voltage (C-V) measurements on MOS capacitors and\\u000a current-voltage (I-V) measurements on Schottky barriers. A simple interface state model cannot explain the observed behavior.\\u000a Schottky barrier measurements made on surfaces which were previously anodized with the oxide layer subsequently removed by\\u000a etching show evidence for the presence of a compensated layer in the

S. Varadarajan; M. A. Littlejohn; J. R. Hauser



A computational model for stress reduction at the skin-implant interface of osseointegrated prostheses.  


Osseointegrated implants (OI)s for transfemoral prosthetic attachment offer amputees an alternative to the traditional socket attachment. Potential benefits include a natural transfer of loads directly to the skeleton via the percutaneous abutment, relief of pain and discomfort of residual limb soft tissues by eliminating sockets, increased sensory feedback, and improved function. Despite the benefits, the skin-implant interface remains a critical limitation, as it is highly prone to bacterial infection. One approach to improve clinical outcomes is to minimize stress concentrations at the skin-implant interface due to shear loading, reducing soft tissue breakdown and subsequent risk of infection. We hypothesized that broadening the bone base at the distal end of the femur would provide added surface area for skin adhesion and reduce stresses at the skin-implant interface. We tested this hypothesis using finite element models of an OI in a residual limb. Results showed a dramatic decrease in stress reduction, with up to ~90% decrease in stresses at the skin-implant interface as cortical bone thickness increased from 2 to 8 mm. The findings in this study suggests that surgical techniques could stabilize the skin-implant interface, thus enhancing a skin-to-bone seal around the percutaneous device and minimizing infection. PMID:22275149

Yerneni, Srinivasu; Dhaher, Yasin; Kuiken, Todd A



Automated segmentation of psoas major muscle in X-ray CT images by use of a shape model: preliminary study  

Microsoft Academic Search

Our motivation was to provide an automatic tool for radiologists and orthopedic surgeons for improving the quality of life\\u000a of an aging population. We propose a method for generating a shape model and a fully automated segmenting scheme for the psoas\\u000a major muscle in X-ray CT images by using the shape model. Our approach consists of two steps: (1) The

Naoki Kamiya; Xiangrong Zhou; Huayue Chen; Chisako Muramatsu; Takeshi Hara; Ryujiro Yokoyama; Masayuki Kanematsu; Hiroaki Hoshi; Hiroshi Fujita


A Discriminative Model-Constrained Graph Cuts Approach to Fully Automated Pediatric Brain Tumor Segmentation in 3-D MRI  

Microsoft Academic Search

\\u000a In this paper we present a fully automated approach to the segmentation of pediatric brain tumors in multi-spectral 3-D magnetic\\u000a resonance images. It is a top-down segmentation approach based on a Markov random field (MRF) model that combines probabilistic\\u000a boosting trees (PBT) and lower-level segmentation via graph cuts. The PBT algorithm provides a strong discriminative observation\\u000a model that classifies tumor

Michael Wels; Gustavo Carneiro; Alexander Aplas; Martin Huber; Joachim Hornegger; Dorin Comaniciu



The contact line behaviour of solid-liquid-gas diffuse-interface models  

NASA Astrophysics Data System (ADS)

A solid-liquid-gas moving contact line is considered through a diffuse-interface model with the classical boundary condition of no-slip at the solid surface. Examination of the asymptotic behaviour as the contact line is approached shows that the relaxation of the classical model of a sharp liquid-gas interface, whilst retaining the no-slip condition, resolves the stress, and pressure singularities associated with the moving contact line problem while the fluid velocity is well defined (not multi-valued). The moving contact line behaviour is analysed for a general problem relevant for any density dependent dynamic viscosity and volume viscosity, and for general microscopic contact angle and double well free-energy forms. Away from the contact line, analysis of the diffuse-interface model shows that the Navier-Stokes equations and classical interfacial boundary conditions are obtained at leading order in the sharp-interface limit, justifying the creeping flow problem imposed in an intermediate region in the seminal work of Seppecher [Int. J. Eng. Sci. 34, 977-992 (1996)]. Corrections to Seppecher's work are given, as an incorrect solution form was originally used.

Sibley, David N.; Nold, Andreas; Savva, Nikos; Kalliadasis, Serafim



Modeling of tunneling current in ultrathin MOS structure with interface trap charge and fixed oxide charge  

NASA Astrophysics Data System (ADS)

A model based on analysis of the self-consistent Poisson—Schrodinger equation is proposed to investigate the tunneling current of electrons in the inversion layer of a p-type metal-oxide-semiconductor (MOS) structure. In this model, the influences of interface trap charge (ITC) at the Si—SiO2 interface and fixed oxide charge (FOC) in the oxide region are taken into account, and one-band effective mass approximation is used. The tunneling probability is obtained by employing the transfer matrix method. Further, the effects of in-plane momentum on the quantization in the electron motion perpendicular to the Si—SiO2 interface of a MOS device are investigated. Theoretical simulation results indicate that both ITC and FOC have great influence on the tunneling current through a MOS structure when their densities are larger than 1012 cm-2, which results from the great change of bound electrons near the Si—SiO2 interface and the oxide region. Therefore, for real ultrathin MOS structures with ITC and FOC, this model can give a more accurate description for the tunneling current in the inversion layer.

Hu, Bo; Huang, Shi-Hua; Wu, Feng-Min



Effect of fluid circulation on subduction interface tectonic processes: Insights from thermo-mechanical numerical modelling  

NASA Astrophysics Data System (ADS)

Both geophysical and petrological data suggest that large amounts of water are released in subduction zones during the burial of oceanic lithosphere through metamorphic dehydration reactions. These fluids are generally considered to be responsible for mantle wedge hydration, mechanical weakening of the plate interface and to affect slab-interface seismicity. In order to bridge the gap between subduction dynamics and the wealth of field, petrological and experimental data documenting small-scale fluid circulation at mantle depths, we designed a bi-phase model, in which fluid migration is driven by rock fluid concentrations, non-lithostatic pressure gradients and deformation. Oceanic subduction is modelled using a forward visco-elasto-plastic thermo-mechanically and thermodynamically coupled code (FLAMAR) following the previous work by Yamato et al. (2007). After 16.5 Myr of convergence, deformation is accommodated along the subduction interface by a low-strength shear zone characterised by a weak (10-25% of serpentinite) and relatively narrow (5-10 km) serpentinized front in the reference experiment. Dehydration associated with eclogitization of the oceanic crust (60-75 km depth) and serpentinite breakdown (110-130 km depth) significantly decreases the mechanical strength of the mantle at these depths, thereby favouring the detachment of large slices of oceanic crust along the plate interface. The geometries obtained are in good agreement with reconstructions derived from field evidence from the Alpine eclogite-facies ophiolitic belt (i.e., coherent fragments of oceanic crust detached at ca.80 km depth in the Alpine subduction zone and exhumed along the subduction interface). Through a parametric study, we further investigate the role of various parameters, such as fluid circulation, oceanic crustal structure and rheology, on the formation of such large tectonic slices. We conclude that the detachment of oceanic crust slices is largely promoted by fluid circulation along the subduction interface and by the subduction of a strong and originally discontinuous mafic crust.

Angiboust, S.; Wolf, S.; Burov, E.; Agard, P.; Yamato, P.



Automated choroidal segmentation of 1060 nm OCT in healthy and pathologic eyes using a statistical model  

PubMed Central

A two stage statistical model based on texture and shape for fully automatic choroidal segmentation of normal and pathologic eyes obtained by a 1060 nm optical coherence tomography (OCT) system is developed. A novel dynamic programming approach is implemented to determine location of the retinal pigment epithelium/ Bruch’s membrane /choriocapillaris (RBC) boundary. The choroid–sclera interface (CSI) is segmented using a statistical model. The algorithm is robust even in presence of speckle noise, low signal (thick choroid), retinal pigment epithelium (RPE) detachments and atrophy, drusen, shadowing and other artifacts. Evaluation against a set of 871 manually segmented cross-sectional scans from 12 eyes achieves an average error rate of 13%, computed per tomogram as a ratio of incorrectly classified pixels and the total layer surface. For the first time a fully automatic choroidal segmentation algorithm is successfully applied to a wide range of clinical volumetric OCT data.

Kajic, Vedran; Esmaeelpour, Marieh; Povazay, Boris; Marshall, David; Rosin, Paul L.; Drexler, Wolfgang



Ion pairing and dissociation at liquid\\/liquid interfaces: Molecular dynamics and continuum models  

Microsoft Academic Search

The thermodynamics and dynamics of NaCl ion-pair dissociation at the water\\/1,2-dichloroethane liquid\\/liquid interface are examined using a continuum electrostatic model, molecular dynamics free energy calculations, and nonequilibrium dynamic trajectory calculations. The continuum model shows increased stability of the ion pair relative to that in bulk water and strong dependence of the potential of mean force on the orientation and location

Karl Schweighofer; Ilan Benjamin



Dynamic lattice Monte Carlo simulation of a model protein at an oil\\/water interface  

Microsoft Academic Search

Adsorption of a proteinlike heteropolymer is modeled at an oil\\/water interface by dynamic lattice Monte Carlo simulation. The heteropolymer is a designed sequence of 27 amino-acid-type lattice sites and has been used as a model for short (50-70) residue proteins. Oil is represented by a characteristic hydrophobic amino acid monomer, and water is represented by a characteristic hydrophilic amino acid

Rebeccah E. Anderson; Vijay S. Pande; Clayton J. Radke



Dynamic lattice Monte Carlo simulation of a model protein at an oil\\/water interface  

Microsoft Academic Search

Adsorption of a proteinlike heteropolymer is modeled at an oil\\/water interface by dynamic lattice Monte Carlo simulation. The heteropolymer is a designed sequence of 27 amino-acid-type lattice sites and has been used as a model for short (50–70) residue proteins. Oil is represented by a characteristic hydrophobic amino acid monomer, and water is represented by a characteristic hydrophilic amino acid

Rebeccah E. Anderson; Vijay S. Pande; Clayton J. Radke



A Study of User Interface Aids for Model-Oriented Decision Support Systems  

Microsoft Academic Search

The growing importance of DSS for both strategy evaluation and end user computing increases the need to provide research-based guidance for the design of user interface aids. This research study addresses the common belief that greater flexibility and choice in software aids will promote improved user performance. For model-based decision support systems, the effects of user vs. system-guided model manipulation,

Brian L. Dos Santos; Martin L. Bariff



A penalty-based interface technology for connecting independently modeled substructures and for simulating growth of delamination in composite structures  

Microsoft Academic Search

An effective and robust interface element technology able to connect independently modeled finite element subdomains is presented. This method has been developed using penalty constraints and allows coupling of finite element models whose nodes do not coincide along their common interface. Additionally, the present formulation leads to a computational approach that is very efficient and completely compatible with existing commercial

Antonio Pantano



A novel artificial neural network fire model for prediction of thermal interface location in single compartment fire  

Microsoft Academic Search

Thermal interface is the boundary between the hot and cold gases layers in a compartment fire. The height of the interface depends predominantly on the mass of air entrained into the fire plume. However, the analytical determination of the air mass flow rate is complicated since it is highly nonlinear in nature. Currently, computer models including zone models and field

Eric W. M. Lee; Richard K. K. Yuen; S. M. Lo; K. C. Lam; G. H. Yeoh



An elasto-viscoplastic interface model for investigating the constitutive behavior of nacre  

NASA Astrophysics Data System (ADS)

In order to better understand the strengthening mechanism observed in nacre, we have developed an interface computational model to simulate the behavior of the organic present at the interface between aragonite tablets. In the model, the single polymer-chain behavior is characterized by the worm-like-chain (WLC) model, which is in turn incorporated into the eight-chain cell model developed by Arruda and Boyce [Arruda, E.M., Boyce, M.C., 1993a. A three-dimensional constitutive model for the large stretches, with application to polymeric glasses. Int. J. Solids Struct. 40, 389 412] to achieve a continuum interface constitutive description. The interface model is formulated within a finite-deformation framework. A fully implicit time-integration algorithm is used for solving the discretized governing equations. Finite element simulations were performed on a representative volume element (RVE) to investigate the tensile response of nacre. The staggered arrangement of tablets and interface waviness obtained experimentally by Barthelat et al. [Barthelat, F., Tang, H., Zavattieri, P.D., Li, C.-M., Espinosa, H.D., 2007. On the mechanics of mother-of-pearl: a key feature in the material hierarchical structure. J. Mech. Phys. Solids 55 (2), 306 337] was included in the RVE simulations. The simulations showed that both the rate-dependence of the tensile response and hysteresis loops during loading, unloading and reloading cycles were captured by the model. Through a parametric study, the effect of the polymer constitutive response during tablet-climbing and its relation to interface hardening was investigated. It is shown that stiffening of the organic material is not required to achieve the experimentally observed strain hardening of nacre during tension. In fact, when ratios of contour length/persistent length experimentally identified are employed in the simulations, the predicted stress strain behavior exhibits a deformation hardening consistent with the one measured experimentally and also captured by the phenomenological cohesive model used in the study carried out by Barthelat et al. [Barthelat, F., Tang, H., Zavattieri, P.D., Li, C.-M., Espinosa, H.D., 2007. On the mechanics of mother-of-pearl: a key feature in the material hierarchical structure. J. Mech. Phys. Solids 55 (2), 306 337]. The simulation results also reveal that the bulk modulus of the polymer controls the rate of hardening, feature not captured by more simple cohesive laws.

Tang, H.; Barthelat, F.; Espinosa, H. D.



Integrated surface and groundwater modelling in the Thames Basin, UK using the Open Modelling Interface  

NASA Astrophysics Data System (ADS)

The River Thames catchment is situated in the south-east of England. It covers approximately 16,000 km2 and is the most heavily populated river basin in the UK. It is also one of the driest and has experienced severe drought events in the recent past. With the onset of climate change and human exploitation of our environment, there are now serious concerns over the sustainability of water resources in this basin with 6 million m3 consumed every day for public water supply alone. Groundwater in the Thames basin is extremely important, providing 40% of water for public supply. The principal aquifer is the Chalk, a dual permeability limestone, which has been extensively studied to understand its hydraulic properties. The fractured Jurassic limestone in the upper catchment also forms an important aquifer, supporting baseflow downstream during periods of drought. These aquifers are unconnected other than through the River Thames and its tributaries, which provide two-thirds of London's drinking water. Therefore, to manage these water resources sustainably and to make robust projections into the future, surface and groundwater processes must be considered in combination. This necessitates the simulation of the feedbacks and complex interactions between different parts of the water cycle, and the development of integrated environmental models. The Open Modelling Interface (OpenMI) standard provides a method through which environmental models of varying complexity and structure can be linked, allowing them to run simultaneously and exchange data at each timestep. This architecture has allowed us to represent the surface and subsurface flow processes within the Thames basin at an appropriate level of complexity based on our understanding of particular hydrological processes and features. We have developed a hydrological model in OpenMI which integrates a process-driven, gridded finite difference groundwater model of the Chalk with a more simplistic, semi-distributed conceptual model of the Jurassic limestone. A distributed river routing model of the Thames has also been integrated to connect the surface and subsurface hydrological processes. This application demonstrates the potential benefits and issues associated with implementing this approach.

Mackay, Jonathan; Abesser, Corinna; Hughes, Andrew; Jackson, Chris; Kingdon, Andrew; Mansour, Majdi; Pachocka, Magdalena; Wang, Lei; Williams, Ann



Psychovegetative syndrome diagnosis: an automated psychophysiological investigation and mathematical modeling approach.  


1. INTRODUCTION. The main purpose of our work was to create the informational expert system of psychovegetative syndrome diagnosis by applying clinical data and estimating the functioning of the central and peripheral part of regulatory apparatus of the human organism, taking into consideration parallel and consecutive sensory, motor, associative, emotional drive systems, and internal body state. We used automatized psychophysiological investigation and mathematical models. For this purpose the following principal tasks have been prepared: the creation of database of quantifiable estimation patient state; the definition and automation of psychophysiological investigation; mathematical modeling of vegetative functions using a non-invasive sample and its connection with real psychophysiological experiment; mathematical modeling of organisms inner medium homeostasis; and the creation of an informational-expert system of psychovegetative syndrome diagnosis. 2. DATABASE OF ESTIMATION OF PATIENTS STATE. The medical records of the DB "PATIENT" contain data on patient psychic and somatoneurological status. 3. AUTOMATED PSYCHOPHYSIOLOGICAL INVESTIGATION. Psychophysiological investigation enables estimation of the functioning of several subsystems of the human organism and establishes an interrelationship between them by means of electrophysiological data and performance parameters. The study of psychophysiological provision of behavior by psychophysiological investigation enables us to get information about adaptational mechanisms of the patient under certain environmental loads. By means of special mathematical provision, the mathematical elaboration of biosignals as performance parameters has been realized; also realized were the formation of received parameters in the database, the estimation of separated parameters in the view of informativity, and the establishment of diagnostic patterns. 4. MATHEMATICAL MODELS FOR ESTIMATION INTERNAL BODY STATE. The proposed mathematical models allow investigation of homeostatic regulation in various intensities of the metabolic processes and external load. This approach in mathematical models allows us to characterize the relations between the central and peripheral parts of the regulatory mechanisms, using non-invasive samples under psychophysiological investigation and the simulation of different surroundings for brain cells functioning. 5. INFORMATION-EXPERT SYSTEM. Proceeding from the principle of psychoneural unity, we characterized the functioning mechanisms of CNS by means of automatized EEG analysis, visually evoked potential analysis, estimated psychic status, and the characteristics of neural system biochemical processes received by mathematical modeling. By using the indices of the viscero-vegetative and somatolocomotor system (as well as parameters received by automatized analysis of ECG), the EEG respiratory signal--from mathematical models of vegetative functions decision support system applied in estimation of a peripheral block of the regulatory system--is reflected in diagnosis of certain syndromes. The informational expert system, proceeding from the functioning of the human organism's regulatory apparatus, diagnosed psychovegetative syndrome and described the mechanisms of its development. 6. CONCLUSION. The informational expert system enables estimation of the functioning of a human organism as a whole and can be introduced in the sphere of practical medicine and professional orientation as well as in laboratories of experimental psychology and neurosciences. PMID:8591596

Brelidze, Z; Samadashvili, Z; Khachapuridze, G; Kubaneishvili, E; Nozadze, Z; Benidze, I; Tsitskishvili, N



A numerical model of submarine debris flow with graphical user interface  

NASA Astrophysics Data System (ADS)

A 1-D numerical model of the downslope spreading of a finite-source subaqueous debris flow is presented. The model incorporates the Bingham, Herschel-Bulkley, and bilinear rheologies of viscoplastic fluids. Any of these rheologies can be selected by the user. The layer-integrated conservation equations of mass and momentum balance are solved in a Lagrangian framework using an explicit finite difference scheme. The flow is assumed to remain laminar throughout the computation. Starting from an initial parabolic shape, the debris mass is allowed to collapse and propagate on a given topography. The code is written in the visual basic programming language and has a graphical user interface. The required input parameters can be specified interactively, and the propagation of the debris flow can be viewed as the solution proceeds. The user interface for the software is described in detail. Simulated results from different rheological models are compared.

Imran, Jasim; Harff, Peter; Parker, Gary



Thermo-Mechanical Modeling of Foil-Supported Carbon Nanotube Array Interface Materials  

NASA Astrophysics Data System (ADS)

A thin metal foil with vertically aligned carbon nanotube (CNT) arrays synthesized on both sides is a new class of thermal interface materials that has demonstrated thermal resistances less than 0.1 cm^2 K/W under moderate pressures. Such interface materials are able to obtain such low resistances due to their unique combination of high thermal conductivity and high conformability to surface roughness. For such structures, the contact resistances between CNT arrays and the adjacent surfaces are the major constituents of total resistance. Here we integrate a recently developed contact mechanics model for CNT arrays with a finite element code that captures the nonlinear mechanical behavior of the interface material and the effects of interface topography on the thermal performance. The developed model elucidates the relative affects of metal foil as well as CNT array deformation on the compliance of the composite structure. The results support previous experimental observations that the combination of foil and CNT array deformation significantly enhances interfacial contact and thermal conductance.

Pour Shahid Saeed Abadi, Parisa; Cola, Baratunde; Graham, Samuel



A double layer model of the gas bubble/water interface.  


Zeta potential is a physico-chemical parameter of particular importance to describe sorption of contaminants at the surface of gas bubbles. Nevertheless, the interpretation of electrophoretic mobilities of gas bubbles is complex. This is due to the specific behavior of the gas at interface and to the excess of electrical charge at interface, which is responsible for surface conductivity. We developed a surface complexation model based on the presence of negative surface sites because the balance of accepting and donating hydrogen bonds is broken at interface. By considering protons adsorbed on these sites followed by a diffuse layer, the electrical potential at the head-end of the diffuse layer is computed and considered to be equal to the zeta potential. The predicted zeta potential values are in very good agreement with the experimental data of H(2) bubbles for a broad range of pH and NaCl concentrations. This implies that the shear plane is located at the head-end of the diffuse layer, contradicting the assumption of the presence of a stagnant diffuse layer at the gas/water interface. Our model also successfully predicts the surface tension of air bubbles in a KCl solution. PMID:22985594

Leroy, Philippe; Jougnot, Damien; Revil, André; Lassin, Arnault; Azaroual, Mohamed



Lattice-gas models of phase separation: interfaces, phase transitions, and multiphase flow  

SciTech Connect

Momentum-conserving lattice gases are simple, discrete, microscopic models of fluids. This review describes their hydrodynamics, with particular attention given to the derivation of macroscopic constitutive equations from microscopic dynamics. Lattice-gas models of phase separation receive special emphasis. The current understanding of phase transitions in these momentum-conserving models is reviewed; included in this discussion is a summary of the dynamical properties of interfaces. Because the phase-separation models are microscopically time irreversible, interesting questions are raised about their relationship to real fluid mixtures. Simulation of certain complex-fluid problems, such as multiphase flow through porous media and the interaction of phase transitions with hydrodynamics, is illustrated.

Rothman, D.H. (Laboratoire de Physique Statistique, Centre National de la Recherche Scientifique, Ecole Normale Superieure, 75005 Paris (France)); Zaleski, S. (Laboratoire de Modelisation en Mecanique, Centre National de la Recherche Scientifique, Universite Pierre et Marie Curie, 75005 Paris (France))



Simple model for linear and nonlinear mixing at unstable fluid interfaces in spherical geometry.  


A simple model was recently described for predicting linear and nonlinear mixing at an unstable planar fluid interface subjected to an arbitrary time-dependent variable acceleration history [J. D. Ramshaw, Phys. Rev. E 58, 5834 (1998)]. Here we present an analogous model for describing the mixing of two adjacent spherical fluid shells of different density resulting from an arbitrary time-dependent mean interface radius R(t). As in the planar case, the model is based on a heuristic expression for the kinetic energy of the system. This expression is based on that for the kinetic energy of a linearly perturbed interface, but with a dynamically renormalized effective wavelength which becomes proportional to the half-width a(t) of the mixing layer in the nonlinear regime. An equation of motion for s=R(2)a is then derived from Lagrange's equations. This evolution equation properly reduces to Plesset's equation for small perturbations, and to the previous planar model in the limit of very large R. The conservation properties of the model are established, and a suitable numerical scheme which preserves these properties is proposed. PMID:11969962

Ramshaw, J D



Interface projection techniques for fluid-structure interaction modeling with moving-mesh methods  

NASA Astrophysics Data System (ADS)

The stabilized space-time fluid-structure interaction (SSTFSI) technique developed by the Team for Advanced Flow Simulation and Modeling (T?AFSM) was applied to a number of 3D examples, including arterial fluid mechanics and parachute aerodynamics. Here we focus on the interface projection techniques that were developed as supplementary methods targeting the computational challenges associated with the geometric complexities of the fluid-structure interface. Although these supplementary techniques were developed in conjunction with the SSTFSI method and in the context of air-fabric interactions, they can also be used in conjunction with other moving-mesh methods, such as the Arbitrary Lagrangian-Eulerian (ALE) method, and in the context of other classes of FSI applications. The supplementary techniques currently consist of using split nodal values for pressure at the edges of the fabric and incompatible meshes at the air-fabric interfaces, the FSI Geometric Smoothing Technique (FSI-GST), and the Homogenized Modeling of Geometric Porosity (HMGP). Using split nodal values for pressure at the edges and incompatible meshes at the interfaces stabilizes the structural response at the edges of the membrane used in modeling the fabric. With the FSI-GST, the fluid mechanics mesh is sheltered from the consequences of the geometric complexity of the structure. With the HMGP, we bypass the intractable complexities of the geometric porosity by approximating it with an “equivalent”, locally-varying fabric porosity. As test cases demonstrating how the interface projection techniques work, we compute the air-fabric interactions of windsocks, sails and ringsail parachutes.

Tezduyar, Tayfun E.; Sathe, Sunil; Pausewang, Jason; Schwaab, Matthew; Christopher, Jason; Crabtree, Jason



A theoretical model and phase field simulation on the evolution of interface roughness in the oxidation process  

NASA Astrophysics Data System (ADS)

An oxidation kinetics model is developed to account for the effects of the oxidation interface curvature and the oxidation-induced volume change or Pilling-Bedworth ratio. For the oxidation of Fe-Cr-Al-Y alloy fiber, the predictions agree well with experimental results. By considering the influence of the oxidation interface curvature on oxidation rates, the evolution of fluctuant oxidation interface is predicted. We also developed the phase field method (PFM) to simulate the evolution of the interface roughness. Both the theoretical model and the PFM results show that the interface will become smooth during high temperature oxidation. Stress distribution and evolution are calculated by PFM, which indicates that the stress level decreases as the interface morphology evolves.

Yang, Fan; Fang, Dai-Ning; Liu, Bin



Linkages Between the Work-family Interface and Work, Family, and Individual OutcomesAn Integrative Model  

Microsoft Academic Search

This article describes the work-family interface and proposes a conceptual model that links the work-family interface to work, family, and individual outcomes through several mediating mechanisms. First, the work-family interface is related to a cognitive assessment of work-family conflict, role balance, or role enhancement. This relationship may be moderated by social categories and coping resources. The assessment of conflict, balance,




A Semi-Automated Wake Survey and Analysis System Applied to Small Models.  

National Technical Information Service (NTIS)

A semi-automated wake survey and data analysis system is described. This system was developed to satisfy the modern needs of the propeller specialist, overcoming the shortcomings of the traditional methods. The salient features of this system are electro-...

N. A. Brown J. P. Tjoenneland



Prototype Model for Automating Nursing Diagnosis, Nurse Care Planning and Patient Classification.  

National Technical Information Service (NTIS)

This project serves as a prototype of an automated nursing care system. The project contains three main components: nursing diagnosis, nursing care plans, and patient classification. The objective of this project is to marry the above three nursing elemen...

G. R. Harmeyer



Systems Operations Studies for Automated Guideway Transit Systems - Discrete Event Simulation Model User's Manual.  

National Technical Information Service (NTIS)

In order to examine specific Automated Guideway Transit (AGT) developments and concepts, and to build a better knowledge base for future decision-making, the Urban Mass Transportation Administration (UMTA) undertook a new program of studies and technology...

J. F. Duke R. Blanchard



Development, modeling and technical implementation of automated control system of soil's moistness by underground irrigation  

Microsoft Academic Search

In this paper a structure of automated control system of soil's moistness within the modular field by underground irrigation is developed and simulated in Simulink Editor of Matlab. Technical implementation of the ACS is proposed.

V. Pastushenko; A. Stetsenko



Automation Hooks Architecture for Flexible Test Orchestration - concept development and validation  

Microsoft Academic Search

The Automation Hooks Architecture Trade Study for Flexible Test Orchestration sought a standardized data- driven alternative to conventional automated test programming interfaces. The study recommended composing the interface using multicast DNS (mDNS\\/SD) service discovery, Representational State Transfer (Restful) Web Services, and Automatic Test Markup Language (ATML). We describe additional efforts to rapidly mature the Automation Hooks Architecture candidate interface definition

Chatwin A. Lansdowne; John R. Maclean; Christopher E. Winton; Patrick A. McCartney



Parallel Interface of the Pravets-16 Personal Computer and Its Application for Communication with ES-1010 Computer in ALPHA-3C Spectrometer Automation System.  

National Technical Information Service (NTIS)

Parallel interface for connection of Pravets-16 personal computer (PC) with other devices is developed. Its application for link with ES-1010 computer permits to transmit data with 20 KByte/rate to a few kilometer distances. Up to 4 Pravets-16 PC can be c...

S. A. Zaporozhets E. V. Chernykh



Modelisation microstructurale en fatigue/fluage a froid des alliages de titane quasi alpha par le modele des automates cellulaires  

NASA Astrophysics Data System (ADS)

Les proprietes d'emploi des alliages de titane sont extremement dependantes a certains aspects des microstructures developpees lors de leur elaboration. Ces microstructures peuvent etre fortement heterogenes du point de vue de leur orientation cristallographique et de leur repartition spatiale. Leurs influences sur le comportement du materiau et son endommagement precoce sont des questions qui sont actuellement soulevees. Dans le present projet de doctorat on chercher a repondre a cette question mais aussi de presenter des solutions tangibles quant a l'utilisation securitaire de ces alliages. Un nouveau modele appele automate cellulaire a ete developpe pour simuler le comportement mecanique des alliages de titane en fatigue-fluage a froid. Ces modeles ont permet de mieux comprendre la correlation entre la microstructure et le comportement mecanique du materiau et surtout une analyse detaillee du comportement local du materiau. Mots-cles: Automate cellulaire, fatigue/fluage, alliage de titane, inclusion d'Eshelby, modelisation

Boutana, Mohammed Nabil


Numerical modeling of the evolution of a generic clay/cement interface  

NASA Astrophysics Data System (ADS)

The long-term evolution of interfaces between different materials in deep geological repositories for nuclear waste is governed by geochemical interactions in conjunction with mass and energy transport processes. A key role for the design of the multi-barrier system is the knowledge of long term changes at the interfaces between different materials. Recently, the GEMS-PSI research package ( for thermodynamic modeling of aquatic (geo)chemical systems by Gibbs Energy Minimization was coupled to the T(hermo)-H(ydro)-M(echanical)-C(hemical) transport code Geosys/Rockflow ( The GEM convex programming approach is complementary to the often-used Law of Mass Action (LMA) approach. It is computationally more expensive than LMA and requires more thermodynamic data, but has advantages for describing complex geochemical environments, like aqueous - solid solution equilibria that include two or more multi-component phases. We believe that the use of GEM method in reactive transport codes is a step towards a more realistic description of complex geochemical systems. The coupled code was verified by a widely used benchmark of dissolution-precipitation in a calcite-dolomite system, the retardation of radium close to a bentontite/cement interface due to incorporation in solid solutions, and the evolution of a generic clay/cement interface. The reactive transport simulations presented in this work were not adapted to specific cement or clay material compositions. We concentrated on a simplified, generic geochemical model and a simplified, diffusion dominated, setup for the transport. This makes it easier to test the coupling of the codes and investigate the effects of the numerical and conceptual parameters (e.g. discretization) on the evolution of the interface.

Kosakowski, G.; Kulik, D. A.; Shao, H.; Dmytrieva, S. V.; Kolditz, O.



Towards Automated Seismic Moment Tensor Inversion in Australia Using 3D Structural Model  

NASA Astrophysics Data System (ADS)

There is significant seismic activity in the region around Australia, largely due to the plate boundaries to the north and to the east of the mainland. This seismicity poses serious seismic and tsunamigenic hazard in a wider region, and risk to coastal areas of Australia, and is monitored by Geoscience Australia (GA) using a network of permanent broadband seismometers within Australia. Earthquake and tsunami warning systems were established by the Australian Government and have been using the waveforms from the GA seismological network. The permanent instruments are augmented by non-GA seismic stations based both within and outside of Australia. In particular, seismic moment tensor (MT) solutions for events around Australia as well as local distances are useful for both warning systems and geophysical studies in general. These monitoring systems, however, currently use only one dimensional, spherically-symmetric models of the Earth for source parameter determination. Recently, a novel 3D model of Australia and the surrounding area has been developed from spectral element simulations [1], taking into account not only velocity heterogeneities, but also radial anisotropy and seismic attenuation. This development, inter alia, introduces the potential of providing significant improvements in MT solution accuracy. Allowing reliable MT solutions with reduced dependence on non-GA stations is a secondary advantage. We studied the feasibility of using 1D versus 3D structural models. The accuracy of the 3D model has been investigated, confirming that these models are in most cases superior to the 1D models. A full MT inversion method using a point source approximation was developed as the first step, keeping in mind that for more complex source time functions, a finite source inversion will be needed. Synthetic experiments have been performed with random noise added to the signal to test the code in the both 1D and 3D setting, using a precomputed library of structural Greens functions. Implementation of this 3D model will improve warning systems, and we present results that are an important step towards automated MT inversion in Australia. [1] Fichtner, A., Kennett, B.L.N., Igel, H., Bunge, H.-P., 2009. Full seismic waveform tomography for upper-mantle structure in the Australasian region using adjoint methods. Geophys. J. Int., in press.

Hingee, M.; Tkalcic, H.; Fichtner, A.; Sambridge, M.; Kennett, B. L.; Gorbatov, A.



Structure and application of an interface program between a geographic-information system and a ground-water flow model  

USGS Publications Warehouse

A computer-program interface between a geographic-information system and a groundwater flow model links two unrelated software systems for use in developing the flow models. The interface program allows the modeler to compile and manage geographic components of a groundwater model within the geographic information system. A significant savings of time and effort is realized in developing, calibrating, and displaying the groundwater flow model. Four major guidelines were followed in developing the interface program: (1) no changes to the groundwater flow model code were to be made; (2) a data structure was to be designed within the geographic information system that follows the same basic data structure as the groundwater flow model; (3) the interface program was to be flexible enough to support all basic data options available within the model; and (4) the interface program was to be as efficient as possible in terms of computer time used and online-storage space needed. Because some programs in the interface are written in control-program language, the interface will run only on a computer with the PRIMOS operating system. (USGS)

Van Metre, P. C.



Hybrid Interface Automata for Component Interfaces  

Microsoft Academic Search

The modelling and verifying of hybrid systems attract more and more attentions recently. Hybrid automaton is widely used to model discrete and continuous behaviors of hybrid systems. In this paper, a hybrid interface automaton(HIA) is proposed based on hybrid automaton to model the interface behaviors of hybrid components. According to the interface type of components, we define two kinds of

Dehui Du; Jing Liu



Modeling of ultrasound transmission through a solid-liquid interface comprising a network of gas pockets  

SciTech Connect

Ultrasonic inspection of sodium-cooled fast reactor requires a good acoustic coupling between the transducer and the liquid sodium. Ultrasonic transmission through a solid surface in contact with liquid sodium can be complex due to the presence of microscopic gas pockets entrapped by the surface roughness. Experiments are run using substrates with controlled roughness consisting of a network of holes and a modeling approach is then developed. In this model, a gas pocket stiffness at a partially solid-liquid interface is defined. This stiffness is then used to calculate the transmission coefficient of ultrasound at the entire interface. The gas pocket stiffness has a static, as well as an inertial component, which depends on the ultrasonic frequency and the radiative mass.

Paumel, K.; Baque, F. [CEA, DEN, Nuclear Technology Department, F-13108 Saint-Paul-lez-Durance (France); Moysan, J.; Corneloup, G. [Laboratoire de Caracterisation Non Destructive, Universite de la Mediterranee, IUT Aix-en-Provence, Avenue Gaston Berger, 13625 Aix-en-Provence (France); Chatain, D. [CNRS, Aix-Marseille Universite, CINAM-UPR3118, Campus de Luminy, Case 913, 13288 Marseille cedex 09 (France)



A user interface for the Kansas Geological Survey slug test model.  


The Kansas Geological Survey (KGS) developed a semianalytical solution for slug tests that incorporates the effects of partial penetration, anisotropy, and the presence of variable conductivity well skins. The solution can simulate either confined or unconfined conditions. The original model, written in FORTRAN, has a text-based interface with rigid input requirements and limited output options. We re-created the main routine for the KGS model as a Visual Basic macro that runs in most versions of Microsoft Excel and built a simple-to-use Excel spreadsheet interface that automatically displays the graphical results of the test. A comparison of the output from the original FORTRAN code to that of the new Excel spreadsheet version for three cases produced identical results. PMID:19583592

Esling, Steven P; Keller, John E


Facilitating access to laboratory guidelines by modeling their contents and designing a computerized user interface.  


Laboratory tests are not always prescribed appropriately. Guidelines for some important laboratory tests have been developed by expert panels in the Parisian region to maximize the appropriateness of laboratory medicine. However; these recommendations are not frequently consulted by physicians and nurses. We developed a system facilitating consultation of these guidelines, to increase their usability. Elements of information contained in these documents were identified and included in recommendations of different categories. UML modeling was used to represent these categories and their relationships to each other in the guidelines. We used the generated model to implement a computerized interface. The prototype interface, based on web-based technology was found to be rapid and easy to use. By clicking on provided keywords, information about the subject sought is highlighted whilst retaining the entire text of the guideline on-screen. PMID:21893797

Yasini, Mobin; Duclos, Catherine; Lamy, Jean-Baptiste; Venot, Alain



Modeling of ultrasound transmission through a solid-liquid interface comprising a network of gas pockets  

NASA Astrophysics Data System (ADS)

Ultrasonic inspection of sodium-cooled fast reactor requires a good acoustic coupling between the transducer and the liquid sodium. Ultrasonic transmission through a solid surface in contact with liquid sodium can be complex due to the presence of microscopic gas pockets entrapped by the surface roughness. Experiments are run using substrates with controlled roughness consisting of a network of holes and a modeling approach is then developed. In this model, a gas pocket stiffness at a partially solid-liquid interface is defined. This stiffness is then used to calculate the transmission coefficient of ultrasound at the entire interface. The gas pocket stiffness has a static, as well as an inertial component, which depends on the ultrasonic frequency and the radiative mass.

Paumel, K.; Moysan, J.; Chatain, D.; Corneloup, G.; Baqué, F.



Fully Automated Non-Native Speech Recognition Using Confusion-Based Acoustic Model Integration and Graphemic Constraints  

Microsoft Academic Search

This paper presents a fully automated approach for the recognition of non-native speech based on acoustic model modification. For a native language (L1) and a spoken language (L2), pronunciation variants of the phones of L2 are automatically extracted from an existing non-native database as a confusion matrix with sequences of phones of L1. This is done using LTs and L2's

Ghazi Bouselmi; Dominique Fohr; Irina Illina; Jean Paul Haton



Interface structures during solid-phase-epitaxial growth in ion implanted semiconductors and a crystallization model  

SciTech Connect

We have investigated the interface structures during solid-phase-epitaxial (SPE) growth in ion implanted silicon and gallium arsenide using high-resolution, cross-section electron microscopy. The crystalline amorphous (c-a) interface during solid-phase-epitaxial growth on )001) faces in silicon was found to be planar with undulations of approx.5 A over 200--500 A intervals. However, above certain dopant concentrations that were much higher than the solubility limits, the SPE growth was completely halted, and the c-a interface was observed to become unstable by developing large undulations that resulted in the formation of twins. The solid-phase-epitaxial growth on )111) faces in Si contained atomically smooth interfaces at first. This was followed by the formation of twins. However, the growth on )001) faces of GaAs was found always to be accompanied by the formation of twins. A model of crystal growth in diamond cubic lattices is presented, which can account for the orientation dependence of SPE growth rates, the nature of interfacial instability, and the formation of twins during SPE growth in Si and GaAs.

Narayan, J.



Designing of Multi-Interface Diverging Experiments to Model Rayleigh-Taylor Growth in Supernovae  

NASA Astrophysics Data System (ADS)

In previous experiments on the Omega Laser, researchers studying blast-wave-driven instabilities have observed the growth of Rayleigh-Taylor instabilities under conditions scaled to the He/H interface of SN1987A. Most of these experiments have been planar experiments, as the energy available proved unable to accelerate enough mass in a diverging geometry. With the advent of the NIF laser, which can deliver hundreds of kJ to an experiment, it is possible to produce 3D, blast-wave-driven, multiple-interface explosions and to study the mixing that develops. We report scaling simulations to model the interface dynamics of a multilayered, diverging Rayleigh-Taylor experiment for NIF using CALE, a hybrid adaptive Lagrangian-Eulerian code developed at LLNL. Specifically, we looked both qualitatively and quantitatively at the Rayleigh-Taylor growth and multi-interface interactions in mass-scaled, spherically divergent systems using different materials. The simulations will assist in the target design process and help choose diagnostics to maximize the information we receive in a particular shot. Simulations are critical for experimental planning, especially for experiments on large-scale facilities. *This research was sponsored by LLNL through contract LLNL B56128 and by the NNSA through DOE Research Grant DE-FG52-04NA00064.

Grosskopf, Michael; Drake, R.; Kuranz, C.; Plewa, T.; Hearn, N.; Meakin, C.; Arnett, D.; Miles, A.; Robey, H.; Hansen, J.; Hsing, W.; Edwards, M.



Imaging Automation  

NASA Astrophysics Data System (ADS)

Multiple software programs, techniques, scripts, and related routines now exist to automate much of the work of taking, processing, analyzing, and extracting data from CCD Images. Five categories of such software programs are examined. The automation capability of Maxim DL and the ASCOM modules is demonstrated, together with specific examples of automation routines to control a telescope, take and process images.

Horne, J. D.



Towards an Open Modelling Interface (OpenMI) the HarmonIT project  

NASA Astrophysics Data System (ADS)

The Water Framework Directive (WFD) poses an immense challenge to water management in Europe. Aiming at a "good ecological status" of surface waters in 2015, integrated river basin management plans need to be in place by 2009, and broadly supported by stakeholders. Information & Communication Technology (ICT) tools, such as computational models, are very helpful in designing river basin management plans (rbmp-s). However, many scientists believe that a single integrated modelling system to support the WFD cannot be developed, and integrated systems need to be quite tailored to the local situation and evolve during a collaborative planning process. As a consequence there is an urgent need to increase the flexibility of modelling systems, such that dedicated model systems can be developed from available building blocks. In the recent past a number of initiatives have been started to develop an IT framework for modelling to meet the required flexibility. In Europe the international project HarmonIT, which is sponsored by the European Commission, is developing and implementing a standard interface for modelling components and other relevant tools: The Open Modelling Interface (OpenMI). This paper describes the HarmonIT project and objectives in general. The current progress is described. It describes the roles for different types of stakeholders in modelling, varying from software coders to non-specialized users of decision support systems. It will provide insight in the requirements imposed when using the OpenMI.

Blind, M.; Gregersen, J. B.



Arcgis-swat: a Geodata Model and GIS Interface for Swat  

NASA Astrophysics Data System (ADS)

This paper presents ArcGIS-SWAT, a geodata model and geographic information system (GIS) interface for the Soil and Water Assessment Tool (SWAT). The ArcGIS-SWAT data model is a system of geodatabases that store SWAT geographic, numeric, and text input data and results in an organized fashion. Thus, it is proposed that a single and comprehensive geodatabase be used as the repository of a SWAT simulation. The ArcGIS-SWAT interface uses programming objects that conform to the Component Object Model (COM) design standard, which facilitate the use of functionality of other Windows-based applications within ArcGIS-SWAT. In particular, the use of MS Excel and MATLAB functionality for data analysis and visualization of results is demonstrated. Likewise, it is proposed to conduct hydrologic model integration through the sharing of information with a not-model-specific hub data model where information common to different models can be stored and from which it can be retrieved. As an example, it is demonstrated how the Hydrologic Modeling System (HMS) ­ a computer application for flood analysis ­ can use information originally developed by ArcGIS-SWAT for SWAT. The application of ArcGIS-SWAT to the Seco Creek watershed in Texas is presented.

Olivera, Francisco; Valenzuela, Milver; Srinivasan, R.; Cho, Janghwoan I.



Divide-and-conquer approach for brain machine interfaces: nonlinear mixture of competitive linear models  

Microsoft Academic Search

Abstract This paper proposes a divide-and-conquer strategy for designing brain machine,interfaces. A nonlinear combination,of competitively trained local linear models (experts) is used to identify the mapping,from neuronal activity in cortical areas associated with arm movement,to the hand position of a primate. The proposed,architecture and the training algorithm are described in detail and numerical performance comparisons with alternative linear and nonlinear

Sung-phil Kim; Justin C. Sanchez; Deniz Erdogmus; Yadunandana N. Rao; Johan Wessberg; José Carlos Príncipe; Miguel Nicolelis



Phase-field method for computationally efficient modeling of solidification with arbitrary interface kinetics  

Microsoft Academic Search

We present mathematical results which dramatically enhance the computational efficiency of the phase-field method for modeling the solidification of a pure material. These results make it possible to resolve a smaller capillary length to interface thickness ratio and thus render smaller undercooling and three-dimensional computations accessible. Furthermore, they allow one to choose computational parameters to produce a Gibbs-Thomson condition with

Alain Karma; Wouter-Jan Rappel



Modeling of nanostructured polymer-metal composite for thermal interface material applications  

Microsoft Academic Search

Previous studies have discovered a unique type of nanostructured polymer-metal composite for thermal interface material with effective thermal conductivity of 8 W\\/mK. It is a promising result but extensive efforts are still required to further enhance the thermal conductivity. Therefore, this paper will try to help the process with modeling and simulation. Calculations reveal the alignment of the fibers have

Zhili Hu; Björn Carlberg; Cong Yue; Xingming Guo; Johan Liu



Of Men, Women, and Computers: Data-Driven Gender Modeling for Improved User Interfaces  

Microsoft Academic Search

Men and women have unique sensibilities for information, which can be tapped to create gender-sensitive user interfaces that appeal more specifically to each sex. Building on previous research in gen- der psychology and also in user modeling, we take a data-driven ap- proach to understanding gender preferences by mining a large corpus of 150,000 weblog entries- half authored by men,

Hugo Liu; Rada Mihalcea



An approximate model and empirical energy function for solute interactions with a water-phosphatidylcholine interface.  

PubMed Central

An empirical model of a liquid crystalline (L alpha phase) phosphatidylcholine (PC) bilayer interface is presented along with a function which calculates the position-dependent energy of associated solutes. The model approximates the interface as a gradual two-step transition, the first step being from an aqueous phase to a phase of reduced polarity, but which maintains a high enough concentration of water and/or polar head group moieties to satisfy the hydrogen bond-forming potential of the solute. The second transition is from the hydrogen bonding/low polarity region to an effectively anhydrous hydrocarbon phase. The "interfacial energies" of solutes within this variable medium are calculated based upon atomic positions and atomic parameters describing general polarity and hydrogen bond donor/acceptor propensities. This function was tested for its ability to reproduce experimental water-solvent partitioning energies and water-bilayer partitioning data. In both cases, the experimental data was reproduced fairly well. Energy minimizations carried out on beta-hexyl glucopyranoside led to identification of a global minimum for the interface-associated glycolipid which exhibited glycosidic torsion angles in agreement with prior results (Hare, B.J., K.P. Howard, and J.H. Prestegard. 1993. Biophys. J. 64:392-398). Molecular dynamics simulations carried out upon this same molecule within the simulated interface led to results which were consistent with a number of experimentally based conclusions from previous work, but failed to quantitatively reproduce an available NMR quadrupolar/dipolar coupling data set (Sanders, C.R., and J.H. Prestegard. 1991. J. Am. Chem. Soc. 113:1987-1996). The proposed model and functions are readily incorporated into computational energy modeling algorithms and may prove useful in future studies of membrane-associated molecules.

Sanders, C R; Schwonek, J P



ZL-DHP lignin model compound at the air-water interface  

Microsoft Academic Search

In this paper we present our surface chemistry studies of enzymatically polymerized, poly-coniferyl alcohol lignin model compound (dehydrogenate polymer a.k.a. ZL-DHP) at the air-water interface. Using the CHCl yMeOH (5:1 3 vyv) spreading solvent, we found an average molecular area of ZL-DHP of approximately 1200 A. The monolayer 2 ?

Miodrag Mici; Jhony Orbulescu; Ksenija Radotic; Milorad Jeremic; Guodong Sui; Yujun Zheng; Roger M. Leblanc


ZL-DHP lignin model compound at the air–water interface  

Microsoft Academic Search

In this paper we present our surface chemistry studies of enzymatically polymerized, poly-coniferyl alcohol lignin model compound (dehydrogenate polymer a.k.a. ZL-DHP) at the air–water interface. Using the CHCl3\\/MeOH (5:1 v\\/v) spreading solvent, we found an average molecular area of ZL-DHP of approximately 1200 Å2. The monolayer expresses a high compressibility with a collapsed area of 500 Å2 and collapsed surface

Miodrag Micic; Jhony Orbulescu; Ksenija Radotic; Milorad Jeremic; Guodong Sui; Yujun Zheng; Roger M Leblanc



Model development, testing and experimentation in a CyberWorkstation for Brain-Machine Interface research  

Microsoft Academic Search

The CyberWorkstation (CW) is an advanced cyber-infrastructure for Brain-Machine Interface (BMI) research. It allows the development, configuration and execution of BMI computational models using high-performance computing resources. The CW's concept is implemented using a software structure in which an “experiment engine” is used to coordinate all software modules needed to capture, communicate and process brain signals and motor-control commands. A

Prapaporn Rattanatamrong; Andréa Matsunaga; Pooja Raiturkar; Diego Mesa; Ming Zhao; B. Mahmoudi; J. DiGiovanna; J. Principe; R. Figueiredo; J. Sanchez; J. Fortes



Fault models of inverter-interfaced distributed generators: Experimental verification and application to fault analysis  

Microsoft Academic Search

This paper investigates the fault behaviour of inverter-interfaced distributed generators in stand-alone net- works. It is shown that the rapid transient response of the inverter control system allows its fault behaviour to be characterised by quasi steady-state equivalent fault models. The choice of inverter control strategy, control reference frame and the method of active current limiting dominate the fault response,

Cornelis A. Plet; Maria Brucoli; John D. F. McDonald; Timothy C. Green



Decay Rates of Interactive Hyperbolic-Parabolic PDE Models with Thermal Effects on the Interface  

Microsoft Academic Search

.    We consider coupled PDE systems comprising of a hyperbolic and a parabolic-like equation with an interface on a portion of\\u000a the boundary. These models are motivated by structural acoustic problems. A specific prototype consists of a wave equation\\u000a defined on a three-dimensional bounded domain ? coupled with a thermoelastic plate equation defined on ?\\u000a \\u000a 0—a flat surface of

I. Lasiecka; C. Lebiedzik



Longitudinal Characterization of Brain Atrophy of a Huntington Disease Mouse Model by Automated Morphological Analyses of Magnetic Resonance Images  

PubMed Central

Mouse models of human diseases play crucial roles in understanding disease mechanisms and developing therapeutic measures. Huntington’s disease (HD) is characterized by striatal atrophy that begins long before the onset of motor symptoms. In symptomatic HD, striatal volumes decline predictably with disease course. Thus, imaging based volumetric measures have been proposed as outcomes for presymptomatic as well as symptomatic clinical trials of HD. Magnetic resonance imaging of the mouse brain structures is becoming widely available and has been proposed as one of the biomarkers of disease progression and drug efficacy testing. However, three-dimensional and quantitative morphological analyses of the brains are not straightforward. In this paper, we describe a tool for automated segmentation and voxel-based morphological analyses of the mouse brains. This tool was applied to a well-established mouse model of Huntington disease, the R6/2 transgenic mouse strain. Comparison between the automated and manual segmentation results showed excellent agreement in most brain regions. The automated method was able to sensitively detect atrophy as early as 3 weeks of age and accurately follow disease progression. Comparison between ex vivo and in vivo MRI suggests that the ex vivo end-point measurement of brain morphology is also a valid approach except for the morphology of the ventricles. This is the first report of longitudinal characterization of brain atrophy in a mouse model of Huntington’s disease by using automatic morphological analysis.

Zhang, Jiangyang; Peng, Qi; Li, Qing; Jahanshad, Neda; Hou, Zhipeng; Jiang, Mali; Masuda, Naoki; Langbehn, Douglas R.; Miller, Michael I.; Mori, Susumu; Ross, Christopher A.; Duan, Wenzhen



Formulation of a model for automating infection surveillance: algorithmic detection of central-line associated bloodstream infection  

PubMed Central

Objective To formulate a model for translating manual infection control surveillance methods to automated, algorithmic approaches. Design We propose a model for creating electronic surveillance algorithms by translating existing manual surveillance practices into automated electronic methods. Our model suggests that three dimensions of expert knowledge be consulted: clinical, surveillance, and informatics. Once collected, knowledge should be applied through a process of conceptualization, synthesis, programming, and testing. Results We applied our framework to central vascular catheter associated bloodstream infection surveillance, a major healthcare performance outcome measure. We found that despite major barriers such as differences in availability of structured data, in types of databases used and in semantic representation of clinical terms, bloodstream infection detection algorithms could be deployed at four very diverse medical centers. Conclusions We present a framework that translates existing practice—manual infection detection—to an automated process for surveillance. Our experience details barriers and solutions discovered during development of electronic surveillance for central vascular catheter associated bloodstream infections at four hospitals in a variety of data environments. Moving electronic surveillance to the next level—availability at a majority of acute care hospitals nationwide—would be hastened by the incorporation of necessary data elements, vocabularies and standards into commercially available electronic health records.

Hota, Bala; Lin, Michael; Doherty, Joshua A; Borlawsky, Tara; Woeltje, Keith; Stevenson, Kurt; Khan, Yosef; Young, Jeremy; Weinstein, Robert A; Trick, William



A coupled cohesive zone model for transient analysis of thermoelastic interface debonding  

NASA Astrophysics Data System (ADS)

A coupled cohesive zone model based on an analogy between fracture and contact mechanics is proposed to investigate debonding phenomena at imperfect interfaces due to thermomechanical loading and thermal fields in bodies with cohesive cracks. Traction-displacement and heat flux-temperature relations are theoretically derived and numerically implemented in the finite element method. In the proposed formulation, the interface conductivity is a function of the normal gap, generalizing the Kapitza constant resistance model to partial decohesion effects. The case of a centered interface in a bimaterial component subjected to thermal loads is used as a test problem. The analysis focuses on the time evolution of the displacement and temperature fields during the transient regime before debonding, an issue not yet investigated in the literature. The solution of the nonlinear numerical problem is gained via an implicit scheme both in space and in time. The proposed model is finally applied to a case study in photovoltaics where the evolution of the thermoelastic fields inside a defective solar cell is predicted.

Sapora, Alberto; Paggi, Marco



Forward and inverse computer modeling of a gravity field resulting from a density interface using Parker-Oldenberg method  

Microsoft Academic Search

FORTRAN programs are presented for forward computation and inversion of two-dimensional gravity anomalies assuming that the causative structure is a density interface at a depth. The Fourier transform of the gravity profile is related in a simple manner to the sum of the Fourier transforms of the powers of the depth to the interface profile. This forward modeling equation can

R. Nagendra; P. V. S. Prasad; V. L. S. Bhimasankaram



Automated quantification of carotid artery stenosis on contrast-enhanced MRA data using a deformable vascular tube model.  


The purpose of this study was to develop and validate a method for automated segmentation of the carotid artery lumen from volumetric MR Angiographic (MRA) images using a deformable tubular 3D Non-Uniform Rational B-Splines (NURBS) model. A flexible 3D tubular NURBS model was designed to delineate the carotid arterial lumen. User interaction was allowed to guide the model by placement of forbidden areas. Contrast-enhanced MRA (CE-MRA) from 21 patients with carotid atherosclerotic disease were included in this study. The validation was performed against expert drawn contours on multi-planar reformatted image slices perpendicular to the artery. Excellent linear correlations were found on cross-sectional area measurement (r = 0.98, P < 0.05) and on luminal diameter (r = 0.98, P < 0.05). Strong match in terms of the Dice similarity indices were achieved: 0.95 ± 0.02 (common carotid artery), 0.90 ± 0.07 (internal carotid artery), 0.87 ± 0.07 (external carotid artery), 0.88 ± 0.09 (carotid bifurcation) and 0.75 ± 0.20 (stenosed segments). Slight overestimation of stenosis grading by the automated method was observed. The mean differences was 7.20% (SD = 21.00%) and 5.2% (SD = 21.96%) when validated against two observers. Reproducibility in stenosis grade calculation by the automated method was high; the mean difference between two repeated analyses was 1.9 ± 7.3%. In conclusion, the automated method shows high potential for clinical application in the analysis of CE-MRA of carotid arteries. PMID:22160666

Suinesiaputra, Avan; de Koning, Patrick J H; Zudilova-Seinstra, Elena; Reiber, Johan H C; van der Geest, Rob J



A dynamic model for the interaction between a solid particle and an advancing solid\\/liquid interface  

Microsoft Academic Search

Most models that describe the interaction of an insoluble particle with an advancing solid-liquid interface are based on the\\u000a assumption of steady state. However, as demonstrated by experimental work, the process does not reach steady state until the\\u000a particle is pushed for a while by the interface. In this work, a dynamic mathematical model was developed. The dynamic model\\u000a demonstrates

Adrian V. Catalina; Sundeep Mukherjee; DORU M. STEFANESCU



Software tool for automated design and cost benefit analysis of offshore grid  

Microsoft Academic Search

This paper discusses a software tool for automated design and cost benefit analysis of an offshore grid. The tool utilises a graphical user interface (GUI) and a catalogue of components (cables, transformers, converters, platforms) to design an offshore wind farm and create the corresponding network model. A set of calculations that includes load flow, cable sizing inspection, reactive power compensation,

Dusko P. Nedic; Muhammad Ali; Jovica V. Milanovic



Automating spectral measurements  

NASA Astrophysics Data System (ADS)

This paper discusses the architecture of software utilized in spectroscopic measurements. As optical coatings become more sophisticated, there is mounting need to automate data acquisition (DAQ) from spectrophotometers. Such need is exacerbated when 100% inspection is required, ancillary devices are utilized, cost reduction is crucial, or security is vital. While instrument manufacturers normally provide point-and-click DAQ software, an application programming interface (API) may be missing. In such cases automation is impossible or expensive. An API is typically provided in libraries (*.dll, *.ocx) which may be embedded in user-developed applications. Users can thereby implement DAQ automation in several Windows languages. Another possibility, developed by FTG as an alternative to instrument manufacturers' software, is the ActiveX application (*.exe). ActiveX, a component of many Windows applications, provides means for programming and interoperability. This architecture permits a point-and-click program to act as automation client and server. Excel, for example, can control and be controlled by DAQ applications. Most importantly, ActiveX permits ancillary devices such as barcode readers and XY-stages to be easily and economically integrated into scanning procedures. Since an ActiveX application has its own user-interface, it can be independently tested. The ActiveX application then runs (visibly or invisibly) under DAQ software control. Automation capabilities are accessed via a built-in spectro-BASIC language with industry-standard (VBA-compatible) syntax. Supplementing ActiveX, spectro-BASIC also includes auxiliary serial port commands for interfacing programmable logic controllers (PLC). A typical application is automatic filter handling.

Goldstein, Fred T.



Studying dissolution with a model integrating solid-liquid interface kinetics and diffusion kinetics.  


A dissolution model that integrates the solid-liquid interface kinetics and the mass transport kinetics is introduced. Such a model reduces to the Noyes-Whitney equation under special conditions, but offers expanded range of applicability and flexibility fitting dissolution profiles when interfacial kinetics and interfacial concentration deviate from the assumptions implied in the Noyes-Whitney equation. General solutions to the integrated dissolution model derived for noninteractive solutes as well as for solutes participating in ionization equilibrium are discussed. Parameters defining the integrated dissolution model are explained conceptually along with practical ways for their determinations. Conditions under which the model exhibits supersaturation features are elaborated. Simulated dissolution profiles using the integrated dissolution model for published experimental data exhibiting supersaturation features are illustrated. PMID:23106346

Gao, Jeff Y



Automated Bayesian model development for frequency detection in biological time series  

PubMed Central

Background A first step in building a mathematical model of a biological system is often the analysis of the temporal behaviour of key quantities. Mathematical relationships between the time and frequency domain, such as Fourier Transforms and wavelets, are commonly used to extract information about the underlying signal from a given time series. This one-to-one mapping from time points to frequencies inherently assumes that both domains contain the complete knowledge of the system. However, for truncated, noisy time series with background trends this unique mapping breaks down and the question reduces to an inference problem of identifying the most probable frequencies. Results In this paper we build on the method of Bayesian Spectrum Analysis and demonstrate its advantages over conventional methods by applying it to a number of test cases, including two types of biological time series. Firstly, oscillations of calcium in plant root cells in response to microbial symbionts are non-stationary and noisy, posing challenges to data analysis. Secondly, circadian rhythms in gene expression measured over only two cycles highlights the problem of time series with limited length. The results show that the Bayesian frequency detection approach can provide useful results in specific areas where Fourier analysis can be uninformative or misleading. We demonstrate further benefits of the Bayesian approach for time series analysis, such as direct comparison of different hypotheses, inherent estimation of noise levels and parameter precision, and a flexible framework for modelling the data without pre-processing. Conclusions Modelling in systems biology often builds on the study of time-dependent phenomena. Fourier Transforms are a convenient tool for analysing the frequency domain of time series. However, there are well-known limitations of this method, such as the introduction of spurious frequencies when handling short and noisy time series, and the requirement for uniformly sampled data. Biological time series often deviate significantly from the requirements of optimality for Fourier transformation. In this paper we present an alternative approach based on Bayesian inference. We show the value of placing spectral analysis in the framework of Bayesian inference and demonstrate how model comparison can automate this procedure.



A multiphase electrokinetic flow model for electrolytes with liquid/liquid interfaces  

NASA Astrophysics Data System (ADS)

A numerical model for electrokinetic flow of multiphase systems with deformable interfaces is presented, based on a combined level set-volume of fluid technique. A new feature is a multiphase formulation of the Nernst–Planck transport equation for advection, diffusion and conduction of individual charge carrier species that ensures their conservation in each fluid phase. The numerical model is validated against the analytical results of Zholkovskij et al. (2002) [1], and results for the problem of two drops coalescing in the presence of mobile charge carriers are presented. The time taken for two drops containing ions to coalesce decreases with increasing ion concentration.

Berry, J. D.; Davidson, M. R.; Harvie, D. J. E.



An explicit formula for the interface tension of the 2D Potts model  

NASA Astrophysics Data System (ADS)

We consider the exact correlation length calculations for the two-dimensional Potts model at the transition point ?_t by Klümper, Schadschneider and Zittartz, and by Buffenoir and Wallon. We argue that the correlation length calculated by the latter authors is the correlation length in the disordered phase and then combine their result with duality and the assumption of complete wetting to give an explicit formula for the order-disorder interface tension ?_od of this model. The result is used to clarify a controversy stemming from different numerical simulations of ?_od.

Borgs, Christian; Janke, Wolfhard



Automated detection of arterial input function in DSC perfusion MRI in a stroke rat model  

NASA Astrophysics Data System (ADS)

Quantitative cerebral blood flow (CBF) estimation requires deconvolution of the tissue concentration time curves with an arterial input function (AIF). However, image-based determination of AIF in rodent is challenged due to limited spatial resolution. We evaluated the feasibility of quantitative analysis using automated AIF detection and compared the results with commonly applied semi-quantitative analysis. Permanent occlusion of bilateral or unilateral common carotid artery was used to induce cerebral ischemia in rats. The image using dynamic susceptibility contrast method was performed on a 3-T magnetic resonance scanner with a spin-echo echo-planar-image sequence (TR/TE = 700/80 ms, FOV = 41 mm, matrix = 64, 3 slices, SW = 2 mm), starting from 7 s prior to contrast injection (1.2 ml/kg) at four different time points. For quantitative analysis, CBF was calculated by the AIF which was obtained from 10 voxels with greatest contrast enhancement after deconvolution. For semi-quantitative analysis, relative CBF was estimated by the integral divided by the first moment of the relaxivity time curves. We observed if the AIFs obtained in the three different ROIs (whole brain, hemisphere without lesion and hemisphere with lesion) were similar, the CBF ratios (lesion/normal) between quantitative and semi-quantitative analyses might have a similar trend at different operative time points. If the AIFs were different, the CBF ratios might be different. We concluded that using local maximum one can define proper AIF without knowing the anatomical location of arteries in a stroke rat model.

Yeh, M.-Y.; Lee, T.-H.; Yang, S.-T.; Kuo, H.-H.; Chyi, T.-K.; Liu, H.-L.



Multivariate model of refractive shift in Descemet-stripping automated endothelial keratoplasty  

PubMed Central

Purpose To relate in situ graft shape in Descemet-stripping automated endothelial keratoplasty (DSAEK) to surgically induced refractive error. Setting Academic eye institute. Methods High frequency arc-scanning ultrasound was performed in 7 patients enrolled in a prospective of microkeratome-assisted endothelial keratoplasty approved by the Investigative Review Board. A region of interest spanning the horizontal meridian was defined for analysis of epithelial, host, graft, and total corneal thicknesses. Graft thickness profiles were fit by quadratic polynomials where the 2nd-order coefficients represent the posterior corneal curvature contributed by the graft. The curvature coefficient and central graft thickness were analyzed as predictors of induced refractive error. Results At final follow-up (mean 5.9 months ± 3.2 [SD]), 3 patients had a hyperopic shift (+2.50 diopters [D] each), 3 had insignificant (< 0.50 D) refractive shifts, and 1 had a myopic shift. In the group with hyperopic shift, a negative lens effect was predicted by positive curvature coefficients, representing grafts that were thinner centrally than peripherally (mean +22.72 ?m/mm2; range +4.95 to +45.17 ?m/mm2). In the group with minimal refractive shift, coefficients were less positive (mean +7.28 ?m/mm2; range +2.01 to +13.82 ?m/mm2). The patient with a myopic shift (?1.00 D) had the only negative curvature coefficient (?0.64 ?m/mm2). In a 2-predictor model of refractive shift, central graft thickness and the curvature coefficient together accounted for 86% of the variance in the refractive response to DSAEK (P = .025). Conclusion Nonuniform thickness profiles and variable central graft thicknesses contribute to refractive shift after DSAEK.

Dupps, William J.; Qian, Ying; Meisler, David M.



Automated identification of potential snow avalanche release areas based on digital elevation models  

NASA Astrophysics Data System (ADS)

The identification of snow avalanche release areas is a very difficult task. The release mechanism of snow avalanches depends on many different terrain, meteorological, snowpack and triggering parameters and their interactions, which are very difficult to assess. In many alpine regions such as the Indian Himalaya, nearly no information on avalanche release areas exists mainly due to the very rough and poorly accessible terrain, the vast size of the region and the lack of avalanche records. However avalanche release information is urgently required for numerical simulation of avalanche events to plan mitigation measures, for hazard mapping and to secure important roads. The Rohtang tunnel access road near Manali, Himachal Pradesh, India, is such an example. By far the most reliable way to identify avalanche release areas is using historic avalanche records and field investigations accomplished by avalanche experts in the formation zones. But both methods are not feasible for this area due to the rough terrain, its vast extent and lack of time. Therefore, we develop an operational, easy-to-use automated potential release area (PRA) detection tool in Python/ArcGIS which uses high spatial resolution digital elevation models (DEMs) and forest cover information derived from airborne remote sensing instruments as input. Such instruments can acquire spatially continuous data even over inaccessible terrain and cover large areas. We validate our tool using a database of historic avalanches acquired over 56 yr in the neighborhood of Davos, Switzerland, and apply this method for the avalanche tracks along the Rohtang tunnel access road. This tool, used by avalanche experts, delivers valuable input to identify focus areas for more-detailed investigations on avalanche release areas in remote regions such as the Indian Himalaya and is a precondition for large-scale avalanche hazard mapping.

Bühler, Y.; Kumar, S.; Veitinger, J.; Christen, M.; Stoffel, A.; Snehmani



Numerical modelling of convection in a reactive porous medium with a mobile mush liquid interface  

NASA Astrophysics Data System (ADS)

We describe a series of numerical simulations of dissolution-driven convection in a reactive porous medium heated from above. The physical system consists of a porous medium made of the frozen component of a binary mixture that is immersed in a liquid mixture with which it is in thermodynamic equilibrium. Surface heating results in melting of the uppermost material which releases dense solute and drives compositional convection. An interface develops between the upper region, in which the solid matrix has completely melted, and a lower region, in which the frozen solute evolves. The interface descends as melting proceeds. During the numerical simulations, scaled to be similar to previous experiments using potassium nitrate crystals and their saturated aqueous solution (Hallworth, Huppert & Woods, J. Fluid Mech. vol. 535, 2004, p. 255), there are three distinct phases: a purely conductive phase; followed by a phase with very brief, intense, compositionally driven convection; followed by a prolonged phase of more sedate compositionally driven convection in which the average kinetic energy is roughly one order of magnitude less than during the intense early phase. The field equations and the numerical methodology are presented in addition to a simple analytical model for the rate of motion of the interface. The analytical model, valid in the limit of very rapid mixing of the solute, is shown to be in good agreement with the numerical results of purely conductive calculations with a large diffusion coefficient. We investigate solutions for various values of the Rayleigh number and quantify the degree of interface motion as a function of this parameter. These simulations may be particularly applicable to problems associated with post-cumulate processes in magma chambers.

Butler, S. L.; Huppert, Herbert E.; Grae Worster, M.


Prediction of hot spots in protein interfaces using a random forest model with hybrid features.  


Prediction of hot spots in protein interfaces provides crucial information for the research on protein-protein interaction and drug design. Existing machine learning methods generally judge whether a given residue is likely to be a hot spot by extracting features only from the target residue. However, hot spots usually form a small cluster of residues which are tightly packed together at the center of protein interface. With this in mind, we present a novel method to extract hybrid features which incorporate a wide range of information of the target residue and its spatially neighboring residues, i.e. the nearest contact residue in the other face (mirror-contact residue) and the nearest contact residue in the same face (intra-contact residue). We provide a novel random forest (RF) model to effectively integrate these hybrid features for predicting hot spots in protein interfaces. Our method can achieve accuracy (ACC) of 82.4% and Matthew's correlation coefficient (MCC) of 0.482 in Alanine Scanning Energetics Database, and ACC of 77.6% and MCC of 0.429 in Binding Interface Database. In a comparison study, performance of our RF model exceeds other existing methods, such as Robetta, FOLDEF, KFC, KFC2, MINERVA and HotPoint. Of our hybrid features, three physicochemical features of target residues (mass, polarizability and isoelectric point), the relative side-chain accessible surface area and the average depth index of mirror-contact residues are found to be the main discriminative features in hot spots prediction. We also confirm that hot spots tend to form large contact surface areas between two interacting proteins. Source data and code are available at: PMID:22258275

Wang, Lin; Liu, Zhi-Ping; Zhang, Xiang-Sun; Chen, Luonan



Study of applying CORBA-based distributed object technology to next generation of power dispatching automation system  

Microsoft Academic Search

The distributed object technology and its application in the next generation of a power dispatching automation system are introduced. Standard IEC 61970 is to found common information model (CIM) for the power system objects and to form component interface specifications (CIS) for logical information exchanges among all applications. Standard IEC 61970 is the theoretical basis of data models and distributed

Huang Haifeng; Yang Zhihong; Zhang Shenming



Interfacing comprehensive rotorcraft analysis with advanced aeromechanics and vortex wake models  

NASA Astrophysics Data System (ADS)

This dissertation describes three aspects of the comprehensive rotorcraft analysis. First, a physics-based methodology for the modeling of hydraulic devices within multibody-based comprehensive models of rotorcraft systems is developed. This newly proposed approach can predict the fully nonlinear behavior of hydraulic devices, and pressure levels in the hydraulic chambers are coupled with the dynamic response of the system. The proposed hydraulic device models are implemented in a multibody code and calibrated by comparing their predictions with test bench measurements for the UH-60 helicopter lead-lag damper. Predicted peak damping forces were found to be in good agreement with measurements, while the model did not predict the entire time history of damper force to the same level of accuracy. The proposed model evaluates relevant hydraulic quantities such as chamber pressures, orifice flow rates, and pressure relief valve displacements. This model could be used to design lead-lag dampers with desirable force and damping characteristics. The second part of this research is in the area of computational aeroelasticity, in which an interface between computational fluid dynamics (CFD) and computational structural dynamics (CSD) is established. This interface enables data exchange between CFD and CSD with the goal of achieving accurate airloads predictions. In this work, a loose coupling approach based on the delta-airloads method is developed in a finite-element method based multibody dynamics formulation, DYMORE. To validate this aerodynamic interface, a CFD code, OVERFLOW-2, is loosely coupled with a CSD program, DYMORE, to compute the airloads of different flight conditions for Sikorsky UH-60 aircraft. This loose coupling approach has good convergence characteristics. The predicted airloads are found to be in good agreement with the experimental data, although not for all flight conditions. In addition, the tight coupling interface between the CFD program, OVERFLOW-2, and the CSD program, DYMORE, is also established. The ability to accurately capture the wake structure around a helicopter rotor is crucial for rotorcraft performance analysis. In the third part of this thesis, a new representation of the wake vortex structure based on Non-Uniform Rational B-Spline (NURBS) curves and surfaces is proposed to develop an efficient model for prescribed and free wakes. NURBS curves and surfaces are able to represent complex shapes with remarkably little data. The proposed formulation has the potential to reduce the computational cost associated with the use of Helmholtz's law and the Biot-Savart law when calculating the induced flow field around the rotor. An efficient free-wake analysis will considerably decrease the computational cost of comprehensive rotorcraft analysis, making the approach more attractive to routine use in industrial settings.

Liu, Haiying


Modelling nutrient exchange at the sediment water interface of river systems  

NASA Astrophysics Data System (ADS)

In-stream benthic processes can play a significant role on the water quality of overlying waters flowing through a river network. In order to better understand and quantify the fate of nutrients (nitrogen, phosphorus and silica) during their travel through the river continuum, a deterministic benthic sub-model was developed with the purpose of being connected to a drainage network model. This benthic sub-model resolves the differential equations representing early diagenesis in the sediment, linking the sedimentation rate of organic matter onto the sediment to the resulting flux of nutrients across the sediment water interface. The model has been developed for conditions where sedimentation prevails as well as for situations where net erosion prevents the built-up of a significant sediment layer and where only a biofilm can develop, attached to solid substrates. The benthic model was tested independently of the main water column biological hydrological model to which it is intended to be coupled. For this, three case studies were chosen from the literature representing various sedimentation/erosion conditions: the 8th order river Seine (France), the water storage basin of Méry s/Oise (France), and the headwater stream Orneau (Belgium). The general benthic model has been validated for ammonium, nitrate, oxygen and phosphorus fluxes across the sediment water interface. The capability of the model to correctly predict the observed nutrients profiles within the sediment was also validated for organic carbon, ammonium and phosphorus. An uncertainty analysis showed that using two modelling objectives (observed fluxes and concentration profiles in the sediment) strongly reduces the uncertainty in parameters calibration. A sensitivity analysis illustrated the complexity of the interacting reactions driving each variable, and justifies the usefulness of the model as a tool for understanding and predicting the behaviour of the benthic compartment of river systems.

Thouvenot, Marie; Billen, Gilles; Garnier, Josette



A System for Automated Extraction of Metadata from Scanned Documents using Layout Recognition and String Pattern Search Models.  


One of the most expensive aspects of archiving digital documents is the manual acquisition of context-sensitive metadata useful for the subsequent discovery of, and access to, the archived items. For certain types of textual documents, such as journal articles, pamphlets, official government records, etc., where the metadata is contained within the body of the documents, a cost effective meth