WorldWideScience

Sample records for model spacecraft construction

  1. Modelling Constructs

    DEFF Research Database (Denmark)

    Kindler, Ekkart

    2009-01-01

    , these notations have been extended in order to increase expressiveness and to be more competitive. This resulted in an increasing number of notations and formalisms for modelling business processes and in an increase of the different modelling constructs provided by modelling notations, which makes it difficult......There are many different notations and formalisms for modelling business processes and workflows. These notations and formalisms have been introduced with different purposes and objectives. Later, influenced by other notations, comparisons with other tools, or by standardization efforts...... to compare modelling notations and to make transformations between them. One of the reasons is that, in each notation, the new concepts are introduced in a different way by extending the already existing constructs. In this chapter, we go the opposite direction: We show that it is possible to add most...

  2. Computational Model for Spacecraft/Habitat Volume

    Data.gov (United States)

    National Aeronautics and Space Administration — Please note that funding to Dr. Simon Hsiang, a critical co-investigator for the development of the Spacecraft Optimization Layout and Volume (SOLV) model, was...

  3. Parameter Estimation of Spacecraft Fuel Slosh Model

    Science.gov (United States)

    Gangadharan, Sathya; Sudermann, James; Marlowe, Andrea; Njengam Charles

    2004-01-01

    Fuel slosh in the upper stages of a spinning spacecraft during launch has been a long standing concern for the success of a space mission. Energy loss through the movement of the liquid fuel in the fuel tank affects the gyroscopic stability of the spacecraft and leads to nutation (wobble) which can cause devastating control issues. The rate at which nutation develops (defined by Nutation Time Constant (NTC can be tedious to calculate and largely inaccurate if done during the early stages of spacecraft design. Pure analytical means of predicting the influence of onboard liquids have generally failed. A strong need exists to identify and model the conditions of resonance between nutation motion and liquid modes and to understand the general characteristics of the liquid motion that causes the problem in spinning spacecraft. A 3-D computerized model of the fuel slosh that accounts for any resonant modes found in the experimental testing will allow for increased accuracy in the overall modeling process. Development of a more accurate model of the fuel slosh currently lies in a more generalized 3-D computerized model incorporating masses, springs and dampers. Parameters describing the model include the inertia tensor of the fuel, spring constants, and damper coefficients. Refinement and understanding the effects of these parameters allow for a more accurate simulation of fuel slosh. The current research will focus on developing models of different complexity and estimating the model parameters that will ultimately provide a more realistic prediction of Nutation Time Constant obtained through simulation.

  4. Modeling the fundamental characteristics and processes of the spacecraft functioning

    Science.gov (United States)

    Bazhenov, V. I.; Osin, M. I.; Zakharov, Y. V.

    1986-01-01

    The fundamental aspects of modeling of spacecraft characteristics by using computing means are considered. Particular attention is devoted to the design studies, the description of physical appearance of the spacecraft, and simulated modeling of spacecraft systems. The fundamental questions of organizing the on-the-ground spacecraft testing and the methods of mathematical modeling were presented.

  5. Spacecraft Internal Acoustic Environment Modeling

    Science.gov (United States)

    Chu, Shao-Sheng R.; Allen Christopher S.

    2010-01-01

    Acoustic modeling can be used to identify key noise sources, determine/analyze sub-allocated requirements, keep track of the accumulation of minor noise sources, and to predict vehicle noise levels at various stages in vehicle development, first with estimates of noise sources, later with experimental data. This paper describes the implementation of acoustic modeling for design purposes by incrementally increasing model fidelity and validating the accuracy of the model while predicting the noise of sources under various conditions. During FY 07, a simple-geometry Statistical Energy Analysis (SEA) model was developed and validated using a physical mockup and acoustic measurements. A process for modeling the effects of absorptive wall treatments and the resulting reverberation environment were developed. During FY 08, a model with more complex and representative geometry of the Orion Crew Module (CM) interior was built, and noise predictions based on input noise sources were made. A corresponding physical mockup was also built. Measurements were made inside this mockup, and comparisons were made with the model and showed excellent agreement. During FY 09, the fidelity of the mockup and corresponding model were increased incrementally by including a simple ventilation system. The airborne noise contribution of the fans was measured using a sound intensity technique, since the sound power levels were not known beforehand. This is opposed to earlier studies where Reference Sound Sources (RSS) with known sound power level were used. Comparisons of the modeling result with the measurements in the mockup showed excellent results. During FY 10, the fidelity of the mockup and the model were further increased by including an ECLSS (Environmental Control and Life Support System) wall, associated closeout panels, and the gap between ECLSS wall and mockup wall. The effect of sealing the gap and adding sound absorptive treatment to ECLSS wall were also modeled and validated.

  6. Spacecraft Internal Acoustic Environment Modeling

    Science.gov (United States)

    Chu, SShao-sheng R.; Allen, Christopher S.

    2009-01-01

    Acoustic modeling can be used to identify key noise sources, determine/analyze sub-allocated requirements, keep track of the accumulation of minor noise sources, and to predict vehicle noise levels at various stages in vehicle development, first with estimates of noise sources, later with experimental data. In FY09, the physical mockup developed in FY08, with interior geometric shape similar to Orion CM (Crew Module) IML (Interior Mode Line), was used to validate SEA (Statistical Energy Analysis) acoustic model development with realistic ventilation fan sources. The sound power levels of these sources were unknown a priori, as opposed to previous studies that RSS (Reference Sound Source) with known sound power level was used. The modeling results were evaluated based on comparisons to measurements of sound pressure levels over a wide frequency range, including the frequency range where SEA gives good results. Sound intensity measurement was performed over a rectangular-shaped grid system enclosing the ventilation fan source. Sound intensities were measured at the top, front, back, right, and left surfaces of the and system. Sound intensity at the bottom surface was not measured, but sound blocking material was placed tinder the bottom surface to reflect most of the incident sound energy back to the remaining measured surfaces. Integrating measured sound intensities over measured surfaces renders estimated sound power of the source. The reverberation time T6o of the mockup interior had been modified to match reverberation levels of ISS US Lab interior for speech frequency bands, i.e., 0.5k, 1k, 2k, 4 kHz, by attaching appropriately sized Thinsulate sound absorption material to the interior wall of the mockup. Sound absorption of Thinsulate was modeled in three methods: Sabine equation with measured mockup interior reverberation time T60, layup model based on past impedance tube testing, and layup model plus air absorption correction. The evaluation/validation was

  7. Streamlined Modeling for Characterizing Spacecraft Anomalous Behavior

    Science.gov (United States)

    Klem, B.; Swann, D.

    2011-09-01

    Anomalous behavior of on-orbit spacecraft can often be detected using passive, remote sensors which measure electro-optical signatures that vary in time and spectral content. Analysts responsible for assessing spacecraft operational status and detecting detrimental anomalies using non-resolved imaging sensors are often presented with various sensing and identification issues. Modeling and measuring spacecraft self emission and reflected radiant intensity when the radiation patterns exhibit a time varying reflective glint superimposed on an underlying diffuse signal contribute to assessment of spacecraft behavior in two ways: (1) providing information on body component orientation and attitude; and, (2) detecting changes in surface material properties due to the space environment. Simple convex and cube-shaped spacecraft, designed to operate without protruding solar panel appendages, may require an enhanced level of preflight characterization to support interpretation of the various physical effects observed during on-orbit monitoring. This paper describes selected portions of the signature database generated using streamlined signature modeling and simulations of basic geometry shapes apparent to non-imaging sensors. With this database, summarization of key observable features for such shapes as spheres, cylinders, flat plates, cones, and cubes in specific spectral bands that include the visible, mid wave, and long wave infrared provide the analyst with input to the decision process algorithms contained in the overall sensing and identification architectures. The models typically utilize baseline materials such as Kapton, paints, aluminum surface end plates, and radiators, along with solar cell representations covering the cylindrical and side portions of the spacecraft. Multiple space and ground-based sensors are assumed to be located at key locations to describe the comprehensive multi-viewing aspect scenarios that can result in significant specular reflection

  8. Overview of SDCM - The Spacecraft Design and Cost Model

    Science.gov (United States)

    Ferebee, Melvin J.; Farmer, Jeffery T.; Andersen, Gregory C.; Flamm, Jeffery D.; Badi, Deborah M.

    1988-01-01

    The Spacecraft Design and Cost Model (SDCM) is a computer-aided design and analysis tool for synthesizing spacecraft configurations, integrating their subsystems, and generating information concerning on-orbit servicing and costs. SDCM uses a bottom-up method in which the cost and performance parameters for subsystem components are first calculated; the model then sums the contributions from individual components in order to obtain an estimate of sizes and costs for each candidate configuration within a selected spacecraft system. An optimum spacraft configuration can then be selected.

  9. Modeling and Simulation of Satellite Subsystems for End-to-End Spacecraft Modeling

    National Research Council Canada - National Science Library

    Schum, William K; Doolittle, Christina M; Boyarko, George A

    2006-01-01

    During the past ten years, the Air Force Research Laboratory (AFRL) has been simultaneously developing high-fidelity spacecraft payload models as well as a robust distributed simulation environment for modeling spacecraft subsystems...

  10. MODEL CORRELATION STUDY OF A RETRACTABLE BOOM FOR A SOLAR SAIL SPACECRAFT

    Science.gov (United States)

    Adetona, O.; Keel, L. H.; Oakley, J. D.; Kappus, K.; Whorton, M. S.; Kim, Y. K.; Rakpczy, J. M.

    2005-01-01

    To realize design concepts, predict dynamic behavior and develop appropriate control strategies for high performance operation of a solar-sail spacecraft, we developed a simple analytical model that represents dynamic behavior of spacecraft with various sizes. Since motion of the vehicle is dominated by retractable booms that support the structure, our study concentrates on developing and validating a dynamic model of a long retractable boom. Extensive tests with various configurations were conducted for the 30 Meter, light-weight, retractable, lattice boom at NASA MSFC that is structurally and dynamically similar to those of a solar-sail spacecraft currently under construction. Experimental data were then compared with the corresponding response of the analytical model. Though mixed results were obtained, the analytical model emulates several key characteristics of the boom. The paper concludes with a detailed discussion of issues observed during the study.

  11. Modeling SMAP Spacecraft Attitude Control Estimation Error Using Signal Generation Model

    Science.gov (United States)

    Rizvi, Farheen

    2016-01-01

    Two ground simulation software are used to model the SMAP spacecraft dynamics. The CAST software uses a higher fidelity model than the ADAMS software. The ADAMS software models the spacecraft plant, controller and actuator models, and assumes a perfect sensor and estimator model. In this simulation study, the spacecraft dynamics results from the ADAMS software are used as CAST software is unavailable. The main source of spacecraft dynamics error in the higher fidelity CAST software is due to the estimation error. A signal generation model is developed to capture the effect of this estimation error in the overall spacecraft dynamics. Then, this signal generation model is included in the ADAMS software spacecraft dynamics estimate such that the results are similar to CAST. This signal generation model has similar characteristics mean, variance and power spectral density as the true CAST estimation error. In this way, ADAMS software can still be used while capturing the higher fidelity spacecraft dynamics modeling from CAST software.

  12. Modeling and Analysis of Realistic Fire Scenarios in Spacecraft

    Science.gov (United States)

    Brooker, J. E.; Dietrich, D. L.; Gokoglu, S. A.; Urban, D. L.; Ruff, G. A.

    2015-01-01

    An accidental fire inside a spacecraft is an unlikely, but very real emergency situation that can easily have dire consequences. While much has been learned over the past 25+ years of dedicated research on flame behavior in microgravity, a quantitative understanding of the initiation, spread, detection and extinguishment of a realistic fire aboard a spacecraft is lacking. Virtually all combustion experiments in microgravity have been small-scale, by necessity (hardware limitations in ground-based facilities and safety concerns in space-based facilities). Large-scale, realistic fire experiments are unlikely for the foreseeable future (unlike in terrestrial situations). Therefore, NASA will have to rely on scale modeling, extrapolation of small-scale experiments and detailed numerical modeling to provide the data necessary for vehicle and safety system design. This paper presents the results of parallel efforts to better model the initiation, spread, detection and extinguishment of fires aboard spacecraft. The first is a detailed numerical model using the freely available Fire Dynamics Simulator (FDS). FDS is a CFD code that numerically solves a large eddy simulation form of the Navier-Stokes equations. FDS provides a detailed treatment of the smoke and energy transport from a fire. The simulations provide a wealth of information, but are computationally intensive and not suitable for parametric studies where the detailed treatment of the mass and energy transport are unnecessary. The second path extends a model previously documented at ICES meetings that attempted to predict maximum survivable fires aboard space-craft. This one-dimensional model implies the heat and mass transfer as well as toxic species production from a fire. These simplifications result in a code that is faster and more suitable for parametric studies (having already been used to help in the hatch design of the Multi-Purpose Crew Vehicle, MPCV).

  13. Model predictive control for spacecraft rendezvous in elliptical orbit

    Science.gov (United States)

    Li, Peng; Zhu, Zheng H.

    2018-05-01

    This paper studies the control of spacecraft rendezvous with attitude stable or spinning targets in an elliptical orbit. The linearized Tschauner-Hempel equation is used to describe the motion of spacecraft and the problem is formulated by model predictive control. The control objective is to maximize control accuracy and smoothness simultaneously to avoid unexpected change or overshoot of trajectory for safe rendezvous. It is achieved by minimizing the weighted summations of control errors and increments. The effects of two sets of horizons (control and predictive horizons) in the model predictive control are examined in terms of fuel consumption, rendezvous time and computational effort. The numerical results show the proposed control strategy is effective.

  14. Lifetime of a spacecraft around a synchronous system of asteroids using a dipole model

    Science.gov (United States)

    dos Santos, Leonardo Barbosa Torres; de Almeida Prado, Antonio F. Bertachini; Sanchez, Diogo Merguizo

    2017-11-01

    Space missions allow us to expand our knowledge about the origin of the solar system. It is believed that asteroids and comets preserve the physical characteristics from the time that the solar system was created. For this reason, there was an increase of missions to asteroids in the past few years. To send spacecraft to asteroids or comets is challenging, since these objects have their own characteristics in several aspects, such as size, shape, physical properties, etc., which are often only discovered after the approach and even after the landing of the spacecraft. These missions must be developed with sufficient flexibility to adjust to these parameters, which are better determined only when the spacecraft reaches the system. Therefore, conducting a dynamic investigation of a spacecraft around a multiple asteroid system offers an extremely rich environment. Extracting accurate information through analytical approaches is quite challenging and requires a significant number of restrictive assumptions. For this reason, a numerical approach to the dynamics of a spacecraft in the vicinity of a binary asteroid system is offered in this paper. In the present work, the equations of the Restricted Synchronous Four-Body Problem (RSFBP) are used to model a binary asteroid system. The main objective of this work is to construct grids of initial conditions, which relates semi-major axis and eccentricity, in order to quantify the lifetime of a spacecraft when released close to the less massive body of the binary system (modeled as a rotating mass dipole). We performed an analysis of the lifetime of the spacecraft considering several mass ratios of a binary system of asteroids and investigating the behavior of a spacecraft in the vicinity of this system. We analyze direct and retrograde orbits. This study investigated orbits that survive for at least 500 orbital periods of the system (which is approximately one year), then not colliding or escaping from the system during this

  15. Mechanical Slosh Models for Rocket-Propelled Spacecraft

    Science.gov (United States)

    Jang, Jiann-Woei; Alaniz, Abram; Yang, Lee; Powers. Joseph; Hall, Charles

    2013-01-01

    Several analytical mechanical slosh models for a cylindrical tank with flat bottom are reviewed. Even though spacecrafts use cylinder shaped tanks, most of those tanks usually have elliptical domes. To extend the application of the analytical models for a cylindrical tank with elliptical domes, the modified slosh parameter models are proposed in this report by mapping an elliptical dome cylindrical tank to a flat top/bottom cylindrical tank while maintaining the equivalent liquid volume. For the low Bond number case, the low-g slosh models were also studied. Those low-g models can be used for Bond number > 10. The current low-g slosh models were also modified to extend their applications for the case that liquid height is smaller than the tank radius. All modified slosh models are implemented in MATLAB m-functions and are collected in the developed MST (Mechanical Slosh Toolbox).

  16. Development and evaluation of thermal model reduction algorithms for spacecraft

    Science.gov (United States)

    Deiml, Michael; Suderland, Martin; Reiss, Philipp; Czupalla, Markus

    2015-05-01

    This paper is concerned with the topic of the reduction of thermal models of spacecraft. The work presented here has been conducted in cooperation with the company OHB AG, formerly Kayser-Threde GmbH, and the Institute of Astronautics at Technische Universität München with the goal to shorten and automatize the time-consuming and manual process of thermal model reduction. The reduction of thermal models can be divided into the simplification of the geometry model for calculation of external heat flows and radiative couplings and into the reduction of the underlying mathematical model. For simplification a method has been developed which approximates the reduced geometry model with the help of an optimization algorithm. Different linear and nonlinear model reduction techniques have been evaluated for their applicability in reduction of the mathematical model. Thereby the compatibility with the thermal analysis tool ESATAN-TMS is of major concern, which restricts the useful application of these methods. Additional model reduction methods have been developed, which account to these constraints. The Matrix Reduction method allows the approximation of the differential equation to reference values exactly expect for numerical errors. The summation method enables a useful, applicable reduction of thermal models that can be used in industry. In this work a framework for model reduction of thermal models has been created, which can be used together with a newly developed graphical user interface for the reduction of thermal models in industry.

  17. Modeling, Monitoring and Fault Diagnosis of Spacecraft Air Contaminants

    Science.gov (United States)

    Ramirez, W. Fred; Skliar, Mikhail; Narayan, Anand; Morgenthaler, George W.; Smith, Gerald J.

    1998-01-01

    Control of air contaminants is a crucial factor in the safety considerations of crewed space flight. Indoor air quality needs to be closely monitored during long range missions such as a Mars mission, and also on large complex space structures such as the International Space Station. This work mainly pertains to the detection and simulation of air contaminants in the space station, though much of the work is easily extended to buildings, and issues of ventilation systems. Here we propose a method with which to track the presence of contaminants using an accurate physical model, and also develop a robust procedure that would raise alarms when certain tolerance levels are exceeded. A part of this research concerns the modeling of air flow inside a spacecraft, and the consequent dispersal pattern of contaminants. Our objective is to also monitor the contaminants on-line, so we develop a state estimation procedure that makes use of the measurements from a sensor system and determines an optimal estimate of the contamination in the system as a function of time and space. The real-time optimal estimates in turn are used to detect faults in the system and also offer diagnoses as to their sources. This work is concerned with the monitoring of air contaminants aboard future generation spacecraft and seeks to satisfy NASA's requirements as outlined in their Strategic Plan document (Technology Development Requirements, 1996).

  18. Correlation of spacecraft thermal mathematical models to reference data

    Science.gov (United States)

    Torralbo, Ignacio; Perez-Grande, Isabel; Sanz-Andres, Angel; Piqueras, Javier

    2018-03-01

    Model-to-test correlation is a frequent problem in spacecraft-thermal control design. The idea is to determine the values of the parameters of the thermal mathematical model (TMM) that allows reaching a good fit between the TMM results and test data, in order to reduce the uncertainty of the mathematical model. Quite often, this task is performed manually, mainly because a good engineering knowledge and experience is needed to reach a successful compromise, but the use of a mathematical tool could facilitate this work. The correlation process can be considered as the minimization of the error of the model results with regard to the reference data. In this paper, a simple method is presented suitable to solve the TMM-to-test correlation problem, using Jacobian matrix formulation and Moore-Penrose pseudo-inverse, generalized to include several load cases. Aside, in simple cases, this method also allows for analytical solutions to be obtained, which helps to analyze some problems that appear when the Jacobian matrix is singular. To show the implementation of the method, two problems have been considered, one more academic, and the other one the TMM of an electronic box of PHI instrument of ESA Solar Orbiter mission, to be flown in 2019. The use of singular value decomposition of the Jacobian matrix to analyze and reduce these models is also shown. The error in parameter space is used to assess the quality of the correlation results in both models.

  19. Spacecraft Charging Modeling -- Nascap-2k 2014 Annual Report

    Science.gov (United States)

    2014-09-19

    appears to work similarly in Internet Explorer, FireFox , and Opera, but fails in Safari and Chrome. Note that the SEE Spacecraft Charging Handbook is... Characteristics of Spacecraft Charging in Low Earth Orbit, J Geophys Res. 11 7, doi: 10.1029/20 11JA016875, 2012. 2 M. Cho, K. Saito, T. Hamanaga, Data

  20. A geometric model of a V-slit Sun sensor correcting for spacecraft wobble

    Science.gov (United States)

    Mcmartin, W. P.; Gambhir, S. S.

    1994-01-01

    A V-Slit sun sensor is body-mounted on a spin-stabilized spacecraft. During injection from a parking or transfer orbit to some final orbit, the spacecraft may not be dynamically balanced. This may result in wobble about the spacecraft spin axis as the spin axis may not be aligned with the spacecraft's axis of symmetry. While the widely used models in Spacecraft Attitude Determination and Control, edited by Wertz, correct for separation, elevation, and azimuthal mounting biases, spacecraft wobble is not taken into consideration. A geometric approach is used to develop a method for measurement of the sun angle which corrects for the magnitude and phase of spacecraft wobble. The algorithm was implemented using a set of standard mathematical routines for spherical geometry on a unit sphere.

  1. Modeling Vacuum Arcs On Spacecraft Solar Panel Arrays, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Spacecraft charging and subsequent vacuum arcing poses a significant threat to satellites in LEO and GEO plasma conditions. Localized arc discharges can cause a...

  2. A construction process model for implementing constructability in construction

    NARCIS (Netherlands)

    Langkemper, J.; Al-Jibouri, S.; Reymen, I.M.M.J.; Maas, G.J.; Gassel, van F.

    2003-01-01

    In construction, failure of design professionals to consider how a builder will implement the design can result in scheduling problems, cost escalation, delays and disputes during the construction process. The integration of construction knowledge and experience during planning and design is termed

  3. Economic analysis of open space box model utilization in spacecraft

    Science.gov (United States)

    Mohammad, Atif F.; Straub, Jeremy

    2015-05-01

    It is a known fact that the amount of data about space that is stored is getting larger on an everyday basis. However, the utilization of Big Data and related tools to perform ETL (Extract, Transform and Load) applications will soon be pervasive in the space sciences. We have entered in a crucial time where using Big Data can be the difference (for terrestrial applications) between organizations underperforming and outperforming their peers. The same is true for NASA and other space agencies, as well as for individual missions and the highly-competitive process of mission data analysis and publication. In most industries, conventional opponents and new candidates alike will influence data-driven approaches to revolutionize and capture the value of Big Data archives. The Open Space Box Model is poised to take the proverbial "giant leap", as it provides autonomic data processing and communications for spacecraft. We can find economic value generated from such use of data processing in our earthly organizations in every sector, such as healthcare, retail. We also can easily find retailers, performing research on Big Data, by utilizing sensors driven embedded data in products within their stores and warehouses to determine how these products are actually used in the real world.

  4. Modeling and simulation of satellite subsystems for end-to-end spacecraft modeling

    Science.gov (United States)

    Schum, William K.; Doolittle, Christina M.; Boyarko, George A.

    2006-05-01

    During the past ten years, the Air Force Research Laboratory (AFRL) has been simultaneously developing high-fidelity spacecraft payload models as well as a robust distributed simulation environment for modeling spacecraft subsystems. Much of this research has occurred in the Distributed Architecture Simulation Laboratory (DASL). AFRL developers working in the DASL have effectively combined satellite power, attitude pointing, and communication link analysis subsystem models with robust satellite sensor models to create a first-order end-to-end satellite simulation capability. The merging of these two simulation areas has advanced the field of spacecraft simulation, design, and analysis, and enabled more in-depth mission and satellite utility analyses. A core capability of the DASL is the support of a variety of modeling and analysis efforts, ranging from physics and engineering-level modeling to mission and campaign-level analysis. The flexibility and agility of this simulation architecture will be used to support space mission analysis, military utility analysis, and various integrated exercises with other military and space organizations via direct integration, or through DOD standards such as Distributed Interaction Simulation. This paper discusses the results and lessons learned in modeling satellite communication link analysis, power, and attitude control subsystems for an end-to-end satellite simulation. It also discusses how these spacecraft subsystem simulations feed into and support military utility and space mission analyses.

  5. Application of partial differential equation modeling of the control/structural dynamics of flexible spacecraft

    Science.gov (United States)

    Taylor, Lawrence W., Jr.; Rajiyah, H.

    1991-01-01

    Partial differential equations for modeling the structural dynamics and control systems of flexible spacecraft are applied here in order to facilitate systems analysis and optimization of these spacecraft. Example applications are given, including the structural dynamics of SCOLE, the Solar Array Flight Experiment, the Mini-MAST truss, and the LACE satellite. The development of related software is briefly addressed.

  6. Constructing a Business Model Taxonomy

    DEFF Research Database (Denmark)

    Groth, Pernille; Nielsen, Christian

    2015-01-01

    the quality of business model taxonomy studies in the future are identified. Originality/Value: The paper highlights the benefits and potential implications of designing business model taxonomy studies and makes the case for ensuring the quality of future studies relating to e.g. performance. Reviewing......Abstract Purpose: The paper proposes a research design recipe capable of leading to future business model taxonomies and discusses the potential benefits and implications of achieving this goal. Design/Methodology/Approach: The paper provides a review of relevant scholarly literature about business...... models to clarify the subject as well as highlighting the importance of past studies of business model classifications. In addition it reviews the scholarly literature on relevant methodological approaches, such as cluster analysis and latent class analysis, for constructing a business model taxonomy...

  7. Adaptive relative pose control of spacecraft with model couplings and uncertainties

    Science.gov (United States)

    Sun, Liang; Zheng, Zewei

    2018-02-01

    The spacecraft pose tracking control problem for an uncertain pursuer approaching to a space target is researched in this paper. After modeling the nonlinearly coupled dynamics for relative translational and rotational motions between two spacecraft, position tracking and attitude synchronization controllers are developed independently by using a robust adaptive control approach. The unknown kinematic couplings, parametric uncertainties, and bounded external disturbances are handled with adaptive updating laws. It is proved via Lyapunov method that the pose tracking errors converge to zero asymptotically. Spacecraft close-range rendezvous and proximity operations are introduced as an example to validate the effectiveness of the proposed control approach.

  8. Nonlinear model and attitude dynamics of flexible spacecraft with large amplitude slosh

    Science.gov (United States)

    Deng, Mingle; Yue, Baozeng

    2017-04-01

    This paper is focused on the nonlinearly modelling and attitude dynamics of spacecraft coupled with large amplitude liquid sloshing dynamics and flexible appendage vibration. The large amplitude fuel slosh dynamics is included by using an improved moving pulsating ball model. The moving pulsating ball model is an equivalent mechanical model that is capable of imitating the whole liquid reorientation process. A modification is introduced in the capillary force computation in order to more precisely estimate the settling location of liquid in microgravity or zero-g environment. The flexible appendage is modelled as a three dimensional Bernoulli-Euler beam and the assumed modal method is employed to derive the nonlinear mechanical model for the overall coupled system of liquid filled spacecraft with appendage. The attitude maneuver is implemented by the momentum transfer technique, and a feedback controller is designed. The simulation results show that the liquid sloshing can always result in nutation behavior, but the effect of flexible deformation of appendage depends on the amplitude and direction of attitude maneuver performed by spacecraft. Moreover, it is found that the liquid sloshing and the vibration of flexible appendage are coupled with each other, and the coupling becomes more significant with more rapid motion of spacecraft. This study reveals that the appendage's flexibility has influence on the liquid's location and settling time in microgravity. The presented nonlinear system model can provide an important reference for the overall design of the modern spacecraft composed of rigid platform, liquid filled tank and flexible appendage.

  9. Modeling the angular motion dynamics of spacecraft with a magnetic attitude control system based on experimental studies and dynamic similarity

    Science.gov (United States)

    Kulkov, V. M.; Medvedskii, A. L.; Terentyev, V. V.; Firsyuk, S. O.; Shemyakov, A. O.

    2017-12-01

    The problem of spacecraft attitude control using electromagnetic systems interacting with the Earth's magnetic field is considered. A set of dimensionless parameters has been formed to investigate the spacecraft orientation regimes based on dynamically similar models. The results of experimental studies of small spacecraft with a magnetic attitude control system can be extrapolated to the in-orbit spacecraft motion control regimes by using the methods of the dimensional and similarity theory.

  10. Methodology for Developing a Probabilistic Risk Assessment Model of Spacecraft Rendezvous and Dockings

    Science.gov (United States)

    Farnham, Steven J., II; Garza, Joel, Jr.; Castillo, Theresa M.; Lutomski, Michael

    2011-01-01

    In 2007 NASA was preparing to send two new visiting vehicles carrying logistics and propellant to the International Space Station (ISS). These new vehicles were the European Space Agency s (ESA) Automated Transfer Vehicle (ATV), the Jules Verne, and the Japanese Aerospace and Explorations Agency s (JAXA) H-II Transfer Vehicle (HTV). The ISS Program wanted to quantify the increased risk to the ISS from these visiting vehicles. At the time, only the Shuttle, the Soyuz, and the Progress vehicles rendezvoused and docked to the ISS. The increased risk to the ISS was from an increase in vehicle traffic, thereby, increasing the potential catastrophic collision during the rendezvous and the docking or berthing of the spacecraft to the ISS. A universal method of evaluating the risk of rendezvous and docking or berthing was created by the ISS s Risk Team to accommodate the increasing number of rendezvous and docking or berthing operations due to the increasing number of different spacecraft, as well as the future arrival of commercial spacecraft. Before the first docking attempt of ESA's ATV and JAXA's HTV to the ISS, a probabilistic risk model was developed to quantitatively calculate the risk of collision of each spacecraft with the ISS. The 5 rendezvous and docking risk models (Soyuz, Progress, Shuttle, ATV, and HTV) have been used to build and refine the modeling methodology for rendezvous and docking of spacecrafts. This risk modeling methodology will be NASA s basis for evaluating the addition of future ISS visiting spacecrafts hazards, including SpaceX s Dragon, Orbital Science s Cygnus, and NASA s own Orion spacecraft. This paper will describe the methodology used for developing a visiting vehicle risk model.

  11. First principles nickel-cadmium and nickel hydrogen spacecraft battery models

    Energy Technology Data Exchange (ETDEWEB)

    Timmerman, P.; Ratnakumar, B.V.; Distefano, S.

    1996-02-01

    The principles of Nickel-Cadmium and Nickel-Hydrogen spacecraft battery models are discussed. The Ni-Cd battery model includes two phase positive electrode and its predictions are very close to actual data. But the Ni-H2 battery model predictions (without the two phase positive electrode) are unacceptable even though the model is operational. Both models run on UNIX and Macintosh computers.

  12. Spacecraft Interactions Modeling and Post-Mission Data Analysis

    National Research Council Canada - National Science Library

    Bonito, N

    1996-01-01

    .... In Support of these analyses, models for satellite ephemeris, attitude determination, magnetic fields, atmospheric composition, and particle precipitation were designed and developed, using PL...

  13. Gravity and Macro-Model Tuning for the Geosat Follow-on Spacecraft

    Science.gov (United States)

    Lemoine, Frank G.; Rowlands, David D.; Marr, Gregory C.; Zelensky, Nikita P.; Luthcke, Scott B.; Cox, Christopher M.

    1999-01-01

    The US Navy's GEOSAT Follow-On (GFO) spacecraft was launched on February 10, 1998 and the primary objective of the mission was to map the oceans using a radar altimeter. The spacecraft tracking complement consisted of GPS receivers, a laser retroreflector and Doppler beacons. Since the GPS receivers have not yet returned reliable data, the only means of providing high-quality precise orbits has been though satellite laser ranging (SLR). The spacecraft has been tracked by the international satellite laser ranging network since April 22, 1998, and an average of 7.4 passes per day have been obtained from US and participating foreign stations. Since the predicted radial orbit error due to the gravity field is two to three cm, the largest contributor to the high SLR residuals (7-10 cm RMS for five day arcs) is the mismodelling of the non-conservative forces, not withstanding the development of a three-dimensional eight-panel model and an analytical attitude model for the GFO spacecraft. The SLR residuals show a clear correlation with beta-prime (solar elevation) angle, peaking in mid-August 1998 when the beta-prime angle reached -80 to -90 degrees. In this paper we discuss the tuning of the non-conservative force model, for GFO and report the subsequent addition of the GFO tracking data to the Earth gravity model solutions.

  14. High-Fidelity Dynamic Modeling of Spacecraft in the Continuum--Rarefied Transition Regime

    Science.gov (United States)

    Turansky, Craig P.

    The state of the art of spacecraft rarefied aerodynamics seldom accounts for detailed rigid-body dynamics. In part because of computational constraints, simpler models based upon the ballistic and drag coefficients are employed. Of particular interest is the continuum-rarefied transition regime of Earth's thermosphere where gas dynamic simulation is difficult yet wherein many spacecraft operate. The feasibility of increasing the fidelity of modeling spacecraft dynamics is explored by coupling rarefied aerodynamics with rigid-body dynamics modeling similar to that traditionally used for aircraft in atmospheric flight. Presented is a framework of analysis and guiding principles which capitalize on the availability of increasing computational methods and resources. Aerodynamic force inputs for modeling spacecraft in two dimensions in a rarefied flow are provided by analytical equations in the free-molecular regime, and the direct simulation Monte Carlo method in the transition regime. The application of the direct simulation Monte Carlo method to this class of problems is examined in detail with a new code specifically designed for engineering-level rarefied aerodynamic analysis. Time-accurate simulations of two distinct geometries in low thermospheric flight and atmospheric entry are performed, demonstrating non-linear dynamics that cannot be predicted using simpler approaches. The results of this straightforward approach to the aero-orbital coupled-field problem highlight the possibilities for future improvements in drag prediction, control system design, and atmospheric science. Furthermore, a number of challenges for future work are identified in the hope of stimulating the development of a new subfield of spacecraft dynamics.

  15. Partnering models in Nordic construction

    DEFF Research Database (Denmark)

    Larsen, Jacob Norvig

    of local research and industry partners including major building clients. Data were collected by means of national reviews of partnering policies and practices, thematic analyses, and case studies. The concept partnering was introduced in a Nordic context in the 1990s and has since then been implemented...... in a large number of projects. Clients sought to establish a culture of openness and trust within the project and tried promoting this with various kinds of incentives. In some countries the move towards voluntary collaboration was, paradoxically, strongly advocated by public authorities. Generally, however......Traditionally, procurement and contractual policies adopted by building and construction clients produce a system in which clients procure design services separately from construction services, while operation and maintenance have been subject to further, separate procurement actions...

  16. Planar rigid-flexible coupling spacecraft modeling and control considering solar array deployment and joint clearance

    Science.gov (United States)

    Li, Yuanyuan; Wang, Zilu; Wang, Cong; Huang, Wenhu

    2018-01-01

    Based on Nodal Coordinate Formulation (NCF) and Absolute Nodal Coordinate Formulation (ANCF), this paper establishes rigid-flexible coupling dynamic model of the spacecraft with large deployable solar arrays and multiple clearance joints to analyze and control the satellite attitude under deployment disturbance. Considering torque spring, close cable loop (CCL) configuration and latch mechanisms, a typical spacecraft composed of a rigid main-body described by NCF and two flexible panels described by ANCF is used as a demonstration case. Nonlinear contact force model and modified Coulomb friction model are selected to establish normal contact force and tangential friction model, respectively. Generalized elastic force are derived and all generalized forces are defined in the NCF-ANCF frame. The Newmark-β method is used to solve system equations of motion. The availability and superiority of the proposed model is verified through comparing with numerical co-simulations of Patran and ADAMS software. The numerical results reveal the effects of panel flexibility, joint clearance and their coupling on satellite attitude. The effects of clearance number, clearance size and clearance stiffness on satellite attitude are investigated. Furthermore, a proportional-differential (PD) attitude controller of spacecraft is designed to discuss the effect of attitude control on the dynamic responses of the whole system.

  17. A New Transcendence Model of Identity Construction

    Science.gov (United States)

    Elliott, Christopher L. Wilcox

    2012-01-01

    What does it mean for college men to be authentic? How can we support their efforts to transcend their own immediate needs? And what roles do trusted others play in one's construction of identity? This article describes a preliminary new theoretical model--a Transcendence Model of Identity Construction--based on original research studying…

  18. Template for Conceptual Model Construction: Model Review and Corps Applications

    National Research Council Canada - National Science Library

    Henderson, Jim E; O'Neil, L. J

    2007-01-01

    .... The template will expedite conceptual model construction by providing users with model parameters and potential model components, building on a study team's knowledge and experience, and promoting...

  19. Fractionated Spacecraft Architectures Seeding Study

    National Research Council Canada - National Science Library

    Mathieu, Charlotte; Weigel, Annalisa

    2006-01-01

    .... Models were developed from a customer-centric perspective to assess different fractionated spacecraft architectures relative to traditional spacecraft architectures using multi-attribute analysis...

  20. Estimation Model of Spacecraft Parameters and Cost Based on a Statistical Analysis of COMPASS Designs

    Science.gov (United States)

    Gerberich, Matthew W.; Oleson, Steven R.

    2013-01-01

    The Collaborative Modeling for Parametric Assessment of Space Systems (COMPASS) team at Glenn Research Center has performed integrated system analysis of conceptual spacecraft mission designs since 2006 using a multidisciplinary concurrent engineering process. The set of completed designs was archived in a database, to allow for the study of relationships between design parameters. Although COMPASS uses a parametric spacecraft costing model, this research investigated the possibility of using a top-down approach to rapidly estimate the overall vehicle costs. This paper presents the relationships between significant design variables, including breakdowns of dry mass, wet mass, and cost. It also develops a model for a broad estimate of these parameters through basic mission characteristics, including the target location distance, the payload mass, the duration, the delta-v requirement, and the type of mission, propulsion, and electrical power. Finally, this paper examines the accuracy of this model in regards to past COMPASS designs, with an assessment of outlying spacecraft, and compares the results to historical data of completed NASA missions.

  1. Adaptation and Re-Use of Spacecraft Power System Models for the Constellation Program

    Science.gov (United States)

    Hojnicki, Jeffrey S.; Kerslake, Thomas W.; Ayres, Mark; Han, Augustina H.; Adamson, Adrian M.

    2008-01-01

    NASA's Constellation Program is embarking on a new era of space exploration, returning to the Moon and beyond. The Constellation architecture will consist of a number of new spacecraft elements, including the Orion crew exploration vehicle, the Altair lunar lander, and the Ares family of launch vehicles. Each of these new spacecraft elements will need an electric power system, and those power systems will need to be designed to fulfill unique mission objectives and to survive the unique environments encountered on a lunar exploration mission. As with any new spacecraft power system development, preliminary design work will rely heavily on analysis to select the proper power technologies, size the power system components, and predict the system performance throughout the required mission profile. Constellation projects have the advantage of leveraging power system modeling developments from other recent programs such as the International Space Station (ISS) and the Mars Exploration Program. These programs have developed mature power system modeling tools, which can be quickly modified to meet the unique needs of Constellation, and thus provide a rapid capability for detailed power system modeling that otherwise would not exist.

  2. X-Ray Detection and Processing Models for Spacecraft Navigation and Timing

    Science.gov (United States)

    Sheikh, Suneel; Hanson, John

    2013-01-01

    The current primary method of deepspace navigation is the NASA Deep Space Network (DSN). High-performance navigation is achieved using Delta Differential One-Way Range techniques that utilize simultaneous observations from multiple DSN sites, and incorporate observations of quasars near the line-of-sight to a spacecraft in order to improve the range and angle measurement accuracies. Over the past four decades, x-ray astronomers have identified a number of xray pulsars with pulsed emissions having stabilities comparable to atomic clocks. The x-ray pulsar-based navigation and time determination (XNAV) system uses phase measurements from these sources to establish autonomously the position of the detector, and thus the spacecraft, relative to a known reference frame, much as the Global Positioning System (GPS) uses phase measurements from radio signals from several satellites to establish the position of the user relative to an Earth-centered fixed frame of reference. While a GPS receiver uses an antenna to detect the radio signals, XNAV uses a detector array to capture the individual xray photons from the x-ray pulsars. The navigation solution relies on detailed xray source models, signal processing, navigation and timing algorithms, and analytical tools that form the basis of an autonomous XNAV system. Through previous XNAV development efforts, some techniques have been established to utilize a pulsar pulse time-of-arrival (TOA) measurement to correct a position estimate. One well-studied approach, based upon Kalman filter methods, optimally adjusts a dynamic orbit propagation solution based upon the offset in measured and predicted pulse TOA. In this delta position estimator scheme, previously estimated values of spacecraft position and velocity are utilized from an onboard orbit propagator. Using these estimated values, the detected arrival times at the spacecraft of pulses from a pulsar are compared to the predicted arrival times defined by the pulsar s pulse

  3. Suprathermal ions in the solar wind from the Voyager spacecraft: Instrument modeling and background analysis

    International Nuclear Information System (INIS)

    Randol, B M; Christian, E R

    2015-01-01

    Using publicly available data from the Voyager Low Energy Charged Particle (LECP) instruments, we investigate the form of the solar wind ion suprathermal tail in the outer heliosphere inside the termination shock. This tail has a commonly observed form in the inner heliosphere, that is, a power law with a particular spectral index. The Voyager spacecraft have taken data beyond 100 AU, farther than any other spacecraft. However, during extended periods of time, the data appears to be mostly background. We have developed a technique to self-consistently estimate the background seen by LECP due to cosmic rays using data from the Voyager cosmic ray instruments and a simple, semi-analytical model of the LECP instruments

  4. Light Curve Simulation Using Spacecraft CAD Models and Empirical Material Spectral BRDFS

    Science.gov (United States)

    Willison, A.; Bedard, D.

    This paper presents a Matlab-based light curve simulation software package that uses computer-aided design (CAD) models of spacecraft and the spectral bidirectional reflectance distribution function (sBRDF) of their homogenous surface materials. It represents the overall optical reflectance of objects as a sBRDF, a spectrometric quantity, obtainable during an optical ground truth experiment. The broadband bidirectional reflectance distribution function (BRDF), the basis of a broadband light curve, is produced by integrating the sBRDF over the optical wavelength range. Colour-filtered BRDFs, the basis of colour-filtered light curves, are produced by first multiplying the sBRDF by colour filters, and integrating the products. The software package's validity is established through comparison of simulated reflectance spectra and broadband light curves with those measured of the CanX-1 Engineering Model (EM) nanosatellite, collected during an optical ground truth experiment. It is currently being extended to simulate light curves of spacecraft in Earth orbit, using spacecraft Two-Line-Element (TLE) sets, yaw/pitch/roll angles, and observer coordinates. Measured light curves of the NEOSSat spacecraft will be used to validate simulated quantities. The sBRDF was chosen to represent material reflectance as it is spectrometric and a function of illumination and observation geometry. Homogeneous material sBRDFs were obtained using a goniospectrometer for a range of illumination and observation geometries, collected in a controlled environment. The materials analyzed include aluminum alloy, two types of triple-junction photovoltaic (TJPV) cell, white paint, and multi-layer insulation (MLI). Interpolation and extrapolation methods were used to determine the sBRDF for all possible illumination and observation geometries not measured in the laboratory, resulting in empirical look-up tables. These look-up tables are referenced when calculating the overall sBRDF of objects, where

  5. Radiation properties modeling for plasma-sprayed-alumina-coated rough surfaces for spacecrafts

    International Nuclear Information System (INIS)

    Li, R.M.; Joshi, Sunil C.; Ng, H.W.

    2006-01-01

    Spacecraft thermal control materials (TCMs) play a vital role in the entire service life of a spacecraft . Most of the conventional TCMs degrade in the harmful space environment . In the previous study, plasma sprayed alumina (PSA) coating was established as a new and better TCM for spacecrafts, in view of its stability and reliability compared to the traditional TCMs . During the investigation, the surface roughness of PSA was found important, because the roughness affects the radiative heat exchange between the surface and its surroundings. Parameters such as root-mean-square roughness cannot properly evaluate surface roughness effects on radiative properties of opaque surfaces . Some models have been developed earlier to predict the effects, such as Davies' model , Tang and Buckius's statistical geometric optics model . However, they are valid only in their own specific situations. In this paper, an energy absorption geometry model was developed and applied to investigate the roughness effects with the help of 2D surface profile of PSA coated substrate scanned at micron level. This model predicts effective normal solar absorptance (α ne ) and effective hemispherical infrared emittance (ε he ) of a rough PSA surface. These values, if used in the heat transfer analysis of an equivalent, smooth and optically flat surface, lead to the prediction of the same rate of heat exchange and temperature as that of for the rough PSA surface. The model was validated through comparison between a smooth and a rough PSA coated surfaces. Even though not tested for other types of materials, the model formulation is generic and can be used to incorporate the rough surface effects for other types of thermal coatings, provided the baseline values of normal solar absorptance (α n ) and hemispherical infrared emittance (ε h ) are available for a generic surface of the same material

  6. A Quantitative Human Spacecraft Design Evaluation Model for Assessing Crew Accommodation and Utilization

    Science.gov (United States)

    Fanchiang, Christine

    Crew performance, including both accommodation and utilization factors, is an integral part of every human spaceflight mission from commercial space tourism, to the demanding journey to Mars and beyond. Spacecraft were historically built by engineers and technologists trying to adapt the vehicle into cutting edge rocketry with the assumption that the astronauts could be trained and will adapt to the design. By and large, that is still the current state of the art. It is recognized, however, that poor human-machine design integration can lead to catastrophic and deadly mishaps. The premise of this work relies on the idea that if an accurate predictive model exists to forecast crew performance issues as a result of spacecraft design and operations, it can help designers and managers make better decisions throughout the design process, and ensure that the crewmembers are well-integrated with the system from the very start. The result should be a high-quality, user-friendly spacecraft that optimizes the utilization of the crew while keeping them alive, healthy, and happy during the course of the mission. Therefore, the goal of this work was to develop an integrative framework to quantitatively evaluate a spacecraft design from the crew performance perspective. The approach presented here is done at a very fundamental level starting with identifying and defining basic terminology, and then builds up important axioms of human spaceflight that lay the foundation for how such a framework can be developed. With the framework established, a methodology for characterizing the outcome using a mathematical model was developed by pulling from existing metrics and data collected on human performance in space. Representative test scenarios were run to show what information could be garnered and how it could be applied as a useful, understandable metric for future spacecraft design. While the model is the primary tangible product from this research, the more interesting outcome of

  7. A proposed model for construction project management ...

    African Journals Online (AJOL)

    Keywords: Communication skills and leadership model, construction project ..... help a manager handle stress and break tension (Gido & Clements,. 2012: 331; Harrin .... production and management of projects, the higher the demand for.

  8. A proposed model for construction project management ...

    African Journals Online (AJOL)

    Log in or Register to get access to full text downloads. ... (decision-making, problem-solving, listening, verbal competency, motivation, persuasion, ... Keywords: Communication skills and leadership model, construction project management, ...

  9. Theoretical Models, Assessment Frameworks and Test Construction.

    Science.gov (United States)

    Chalhoub-Deville, Micheline

    1997-01-01

    Reviews the usefulness of proficiency models influencing second language testing. Findings indicate that several factors contribute to the lack of congruence between models and test construction and make a case for distinguishing between theoretical models. Underscores the significance of an empirical, contextualized and structured approach to the…

  10. MODELING THE SOLAR WIND AT THE ULYSSES , VOYAGER , AND NEW HORIZONS SPACECRAFT

    Energy Technology Data Exchange (ETDEWEB)

    Kim, T. K.; Pogorelov, N. V.; Zank, G. P. [Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL 35805 (United States); Elliott, H. A.; McComas, D. J. [Southwest Research Institute, San Antonio, TX 78238 (United States)

    2016-11-20

    The outer heliosphere is a dynamic region shaped largely by the interaction between the solar wind and the interstellar medium. While interplanetary magnetic field and plasma observations by the Voyager spacecraft have significantly improved our understanding of this vast region, modeling the outer heliosphere still remains a challenge. We simulate the three-dimensional, time-dependent solar wind flow from 1 to 80 astronomical units (au), where the solar wind is assumed to be supersonic, using a two-fluid model in which protons and interstellar neutral hydrogen atoms are treated as separate fluids. We use 1 day averages of the solar wind parameters from the OMNI data set as inner boundary conditions to reproduce time-dependent effects in a simplified manner which involves interpolation in both space and time. Our model generally agrees with Ulysses data in the inner heliosphere and Voyager data in the outer heliosphere. Ultimately, we present the model solar wind parameters extracted along the trajectory of the New Horizons spacecraft. We compare our results with in situ plasma data taken between 11 and 33 au and at the closest approach to Pluto on 2015 July 14.

  11. Modeling the Solar Wind at the Ulysses, Voyager, and New Horizons Spacecraft

    Science.gov (United States)

    Kim, T. K.; Pogorelov, N. V.; Zank, G. P.; Elliott, H. A.; McComas, D. J.

    2016-11-01

    The outer heliosphere is a dynamic region shaped largely by the interaction between the solar wind and the interstellar medium. While interplanetary magnetic field and plasma observations by the Voyager spacecraft have significantly improved our understanding of this vast region, modeling the outer heliosphere still remains a challenge. We simulate the three-dimensional, time-dependent solar wind flow from 1 to 80 astronomical units (au), where the solar wind is assumed to be supersonic, using a two-fluid model in which protons and interstellar neutral hydrogen atoms are treated as separate fluids. We use 1 day averages of the solar wind parameters from the OMNI data set as inner boundary conditions to reproduce time-dependent effects in a simplified manner which involves interpolation in both space and time. Our model generally agrees with Ulysses data in the inner heliosphere and Voyager data in the outer heliosphere. Ultimately, we present the model solar wind parameters extracted along the trajectory of the New Horizons spacecraft. We compare our results with in situ plasma data taken between 11 and 33 au and at the closest approach to Pluto on 2015 July 14.

  12. MODELING THE SOLAR WIND AT THE ULYSSES , VOYAGER , AND NEW HORIZONS SPACECRAFT

    International Nuclear Information System (INIS)

    Kim, T. K.; Pogorelov, N. V.; Zank, G. P.; Elliott, H. A.; McComas, D. J.

    2016-01-01

    The outer heliosphere is a dynamic region shaped largely by the interaction between the solar wind and the interstellar medium. While interplanetary magnetic field and plasma observations by the Voyager spacecraft have significantly improved our understanding of this vast region, modeling the outer heliosphere still remains a challenge. We simulate the three-dimensional, time-dependent solar wind flow from 1 to 80 astronomical units (au), where the solar wind is assumed to be supersonic, using a two-fluid model in which protons and interstellar neutral hydrogen atoms are treated as separate fluids. We use 1 day averages of the solar wind parameters from the OMNI data set as inner boundary conditions to reproduce time-dependent effects in a simplified manner which involves interpolation in both space and time. Our model generally agrees with Ulysses data in the inner heliosphere and Voyager data in the outer heliosphere. Ultimately, we present the model solar wind parameters extracted along the trajectory of the New Horizons spacecraft. We compare our results with in situ plasma data taken between 11 and 33 au and at the closest approach to Pluto on 2015 July 14.

  13. Gravity and Nonconservative Force Model Tuning for the GEOSAT Follow-On Spacecraft

    Science.gov (United States)

    Lemoine, Frank G.; Zelensky, Nikita P.; Rowlands, David D.; Luthcke, Scott B.; Chinn, Douglas S.; Marr, Gregory C.; Smith, David E. (Technical Monitor)

    2000-01-01

    The US Navy's GEOSAT Follow-On spacecraft was launched on February 10, 1998 and the primary objective of the mission was to map the oceans using a radar altimeter. Three radar altimeter calibration campaigns have been conducted in 1999 and 2000. The spacecraft is tracked by satellite laser ranging (SLR) and Doppler beacons and a limited amount of data have been obtained from the Global Positioning Receiver (GPS) on board the satellite. Even with EGM96, the predicted radial orbit error due to gravity field mismodelling (to 70x70) remains high at 2.61 cm (compared to 0.88 cm for TOPEX). We report on the preliminary gravity model tuning for GFO using SLR, and altimeter crossover data. Preliminary solutions using SLR and GFO/GFO crossover data from CalVal campaigns I and II in June-August 1999, and January-February 2000 have reduced the predicted radial orbit error to 1.9 cm and further reduction will be possible when additional data are added to the solutions. The gravity model tuning has improved principally the low order m-daily terms and has reduced significantly the geographically correlated error present in this satellite orbit. In addition to gravity field mismodelling, the largest contributor to the orbit error is the non-conservative force mismodelling. We report on further nonconservative force model tuning results using available data from over one cycle in beta prime.

  14. Three-dimensional modeling, estimation, and fault diagnosis of spacecraft air contaminants.

    Science.gov (United States)

    Narayan, A P; Ramirez, W F

    1998-01-01

    A description is given of the design and implementation of a method to track the presence of air contaminants aboard a spacecraft using an accurate physical model and of a procedure that would raise alarms when certain tolerance levels are exceeded. Because our objective is to monitor the contaminants in real time, we make use of a state estimation procedure that filters measurements from a sensor system and arrives at an optimal estimate of the state of the system. The model essentially consists of a convection-diffusion equation in three dimensions, solved implicitly using the principle of operator splitting, and uses a flowfield obtained by the solution of the Navier-Stokes equations for the cabin geometry, assuming steady-state conditions. A novel implicit Kalman filter has been used for fault detection, a procedure that is an efficient way to track the state of the system and that uses the sparse nature of the state transition matrices.

  15. Implementing model-based system engineering for the whole lifecycle of a spacecraft

    Science.gov (United States)

    Fischer, P. M.; Lüdtke, D.; Lange, C.; Roshani, F.-C.; Dannemann, F.; Gerndt, A.

    2017-09-01

    Design information of a spacecraft is collected over all phases in the lifecycle of a project. A lot of this information is exchanged between different engineering tasks and business processes. In some lifecycle phases, model-based system engineering (MBSE) has introduced system models and databases that help to organize such information and to keep it consistent for everyone. Nevertheless, none of the existing databases approached the whole lifecycle yet. Virtual Satellite is the MBSE database developed at DLR. It has been used for quite some time in Phase A studies and is currently extended for implementing it in the whole lifecycle of spacecraft projects. Since it is unforeseeable which future use cases such a database needs to support in all these different projects, the underlying data model has to provide tailoring and extension mechanisms to its conceptual data model (CDM). This paper explains the mechanisms as they are implemented in Virtual Satellite, which enables extending the CDM along the project without corrupting already stored information. As an upcoming major use case, Virtual Satellite will be implemented as MBSE tool in the S2TEP project. This project provides a new satellite bus for internal research and several different payload missions in the future. This paper explains how Virtual Satellite will be used to manage configuration control problems associated with such a multi-mission platform. It discusses how the S2TEP project starts using the software for collecting the first design information from concurrent engineering studies, then making use of the extension mechanisms of the CDM to introduce further information artefacts such as functional electrical architecture, thus linking more and more processes into an integrated MBSE approach.

  16. Modeling Temporal Processes in Early Spacecraft Design: Application of Discrete-Event Simulations for Darpa's F6 Program

    Science.gov (United States)

    Dubos, Gregory F.; Cornford, Steven

    2012-01-01

    While the ability to model the state of a space system over time is essential during spacecraft operations, the use of time-based simulations remains rare in preliminary design. The absence of the time dimension in most traditional early design tools can however become a hurdle when designing complex systems whose development and operations can be disrupted by various events, such as delays or failures. As the value delivered by a space system is highly affected by such events, exploring the trade space for designs that yield the maximum value calls for the explicit modeling of time.This paper discusses the use of discrete-event models to simulate spacecraft development schedule as well as operational scenarios and on-orbit resources in the presence of uncertainty. It illustrates how such simulations can be utilized to support trade studies, through the example of a tool developed for DARPA's F6 program to assist the design of "fractionated spacecraft".

  17. Software for Automated Generation of Reduced Thermal Models for Spacecraft Thermal Control, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Thermal analysis is increasingly used in thermal engineering of spacecrafts in every stage, including design, test, and ground-operation simulation. Current...

  18. Understanding sexual harassment using aggregate construct models.

    Science.gov (United States)

    Nye, Christopher D; Brummel, Bradley J; Drasgow, Fritz

    2014-11-01

    Sexual harassment has received a substantial amount of empirical attention over the past few decades, and this research has consistently shown that experiencing these behaviors has a detrimental effect on employees' well-being, job attitudes, and behaviors at work. However, these findings, and the conclusions that are drawn from them, make the implicit assumption that the empirical models used to examine sexual harassment are properly specified. This article presents evidence that properly specified aggregate construct models are more consistent with theoretical structures and definitions of sexual harassment and can result in different conclusions about the nomological network of harassment. Results from 3 large samples, 2 military and 1 from a civilian population, are used to illustrate the differences between aggregate construct and reflective indicator models of sexual harassment. These analyses suggested that the factor structure and the nomological network of sexual harassment differ when modeling harassment as an aggregate construct. The implications of these results for the continued study of sexual harassment are discussed. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

  19. Spacecraft Multiple Array Communication System Performance Analysis

    Science.gov (United States)

    Hwu, Shian U.; Desilva, Kanishka; Sham, Catherine C.

    2010-01-01

    The Communication Systems Simulation Laboratory (CSSL) at the NASA Johnson Space Center is tasked to perform spacecraft and ground network communication system simulations, design validation, and performance verification. The CSSL has developed simulation tools that model spacecraft communication systems and the space and ground environment in which the tools operate. In this paper, a spacecraft communication system with multiple arrays is simulated. Multiple array combined technique is used to increase the radio frequency coverage and data rate performance. The technique is to achieve phase coherence among the phased arrays to combine the signals at the targeting receiver constructively. There are many technical challenges in spacecraft integration with a high transmit power communication system. The array combining technique can improve the communication system data rate and coverage performances without increasing the system transmit power requirements. Example simulation results indicate significant performance improvement can be achieved with phase coherence implementation.

  20. Item Construction and Psychometric Models Appropriate for Constructed Responses

    Science.gov (United States)

    1991-08-01

    which involve only one attribute per item. This is especially true when we are dealing with constructed-response items, we have to measure much more...Service University of Ilinois Educacional Testing Service Rosedal Road Capign. IL 61801 Princeton. K3 08541 Princeton. N3 08541 Dr. Charles LeiS Dr

  1. CFD Fuel Slosh Modeling of Fluid-Structure Interaction in Spacecraft Propellant Tanks with Diaphragms

    Science.gov (United States)

    Sances, Dillon J.; Gangadharan, Sathya N.; Sudermann, James E.; Marsell, Brandon

    2010-01-01

    Liquid sloshing within spacecraft propellant tanks causes rapid energy dissipation at resonant modes, which can result in attitude destabilization of the vehicle. Identifying resonant slosh modes currently requires experimental testing and mechanical pendulum analogs to characterize the slosh dynamics. Computational Fluid Dynamics (CFD) techniques have recently been validated as an effective tool for simulating fuel slosh within free-surface propellant tanks. Propellant tanks often incorporate an internal flexible diaphragm to separate ullage and propellant which increases modeling complexity. A coupled fluid-structure CFD model is required to capture the damping effects of a flexible diaphragm on the propellant. ANSYS multidisciplinary engineering software employs a coupled solver for analyzing two-way Fluid Structure Interaction (FSI) cases such as the diaphragm propellant tank system. Slosh models generated by ANSYS software are validated by experimental lateral slosh test results. Accurate data correlation would produce an innovative technique for modeling fuel slosh within diaphragm tanks and provide an accurate and efficient tool for identifying resonant modes and the slosh dynamic response.

  2. A Procurement Performance Model for Construction Frameworks

    Directory of Open Access Journals (Sweden)

    Terence Y M Lam

    2015-07-01

    Full Text Available Collaborative construction frameworks have been developed in the United Kingdom (UK to create longer term relationships between clients and suppliers in order to improve project outcomes. Research undertaken into highways maintenance set within a major county council has confirmed that such collaborative procurement methods can improve time, cost and quality of construction projects. Building upon this and examining the same single case, this research aims to develop a performance model through identification of performance drivers in the whole project delivery process including pre and post contract phases. A priori performance model based on operational and sociological constructs was proposed and then checked by a pilot study. Factor analysis and central tendency statistics from the questionnaires as well as content analysis from the interview transcripts were conducted. It was confirmed that long term relationships, financial and non-financial incentives and stronger communication are the sociological behaviour factors driving performance. The interviews also established that key performance indicators (KPIs can be used as an operational measure to improve performance. With the posteriori performance model, client project managers can effectively collaboratively manage contractor performance through procurement measures including use of longer term and KPIs for the contract so that the expected project outcomes can be achieved. The findings also make significant contribution to construction framework procurement theory by identifying the interrelated sociological and operational performance drivers. This study is set predominantly in the field of highways civil engineering. It is suggested that building based projects or other projects that share characteristics are grouped together and used for further research of the phenomena discovered.

  3. Scale model helps Duke untie construction snags

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    A nuclear power plant model, only 60 percent complete, has helped Duke Power identify over 150 major design interferences, which, when resolved, will help cut capital expense and eliminate scheduling problems that normally crop up as revisions are made during actual plant construction. The model has been used by construction, steam production, and design personnel to recommend changes that should improve material handling, operations, and maintenance procedures as well as simplifying piping and cabling. The company has already saved many man-hours in material take-off, material management, and detailed drafting and expects to save even more with greater use of, and improvement in, its modeling program. Duke's modeling program was authorized and became operational in November 1974, with the first model to be the Catawba Nuclear Station. This plant is a two-unit station using Westinghouse nuclear steam supply systems in tandem with General Electric turbine-generators, horizontal feedwater heaters, and Foster Wheeler triple pressure condensers. Each unit is rated 1142 MWe

  4. Materials and techniques for model construction

    Science.gov (United States)

    Wigley, D. A.

    1985-01-01

    The problems confronting the designer of models for cryogenic wind tunnel models are discussed with particular reference to the difficulties in obtaining appropriate data on the mechanical and physical properties of candidate materials and their fabrication technologies. The relationship between strength and toughness of alloys is discussed in the context of maximizing both and avoiding the problem of dimensional and microstructural instability. All major classes of materials used in model construction are considered in some detail and in the Appendix selected numerical data is given for the most relevant materials. The stepped-specimen program to investigate stress-induced dimensional changes in alloys is discussed in detail together with interpretation of the initial results. The methods used to bond model components are considered with particular reference to the selection of filler alloys and temperature cycles to avoid microstructural degradation and loss of mechanical properties.

  5. Conceptual Model for Systematic Construction Waste Management

    OpenAIRE

    Abd Rahim Mohd Hilmi Izwan; Kasim Narimah

    2017-01-01

    Development of the construction industry generated construction waste which can contribute towards environmental issues. Weaknesses of compliance in construction waste management especially in construction site have also contributed to the big issues of waste generated in landfills and illegal dumping area. This gives sign that construction projects are needed a systematic construction waste management. To date, a comprehensive criteria of construction waste management, particularly for const...

  6. Spacecraft Doppler tracking with possible violations of LLI and LPI: a theoretical modeling

    International Nuclear Information System (INIS)

    Deng Xue-Mei; Xie Yi

    2014-01-01

    Currently two-way and three-way spacecraft Doppler tracking techniques are widely used and play important roles in control and navigation of deep space missions. Starting from a one-way Doppler model, we extend the theory to two-way and three-way Doppler models by making them include possible violations of the local Lorentz invariance (LLI) and the local position invariance (LPI) in order to test the Einstein equivalence principle, which is the cornerstone of general relativity and all other metric theories of gravity. After taking the finite speed of light into account, which is the so-called light time solution (LTS), we make these models depend on the time of reception of the signal only for practical convenience. We find that possible violations of LLI and LPI cannot affect two-way Doppler tracking under a linear approximation of LTS, although this approximation is sufficiently good for most cases in the solar system. We also show that, in three-way Doppler tracking, possible violations of LLI and LPI are only associated with two stations, which suggests that it is better to set the stations at places with significant differences in velocities and gravitational potentials to obtain a high level of sensitivity for the tests

  7. Constructive Epistemic Modeling: A Hierarchical Bayesian Model Averaging Method

    Science.gov (United States)

    Tsai, F. T. C.; Elshall, A. S.

    2014-12-01

    Constructive epistemic modeling is the idea that our understanding of a natural system through a scientific model is a mental construct that continually develops through learning about and from the model. Using the hierarchical Bayesian model averaging (HBMA) method [1], this study shows that segregating different uncertain model components through a BMA tree of posterior model probabilities, model prediction, within-model variance, between-model variance and total model variance serves as a learning tool [2]. First, the BMA tree of posterior model probabilities permits the comparative evaluation of the candidate propositions of each uncertain model component. Second, systemic model dissection is imperative for understanding the individual contribution of each uncertain model component to the model prediction and variance. Third, the hierarchical representation of the between-model variance facilitates the prioritization of the contribution of each uncertain model component to the overall model uncertainty. We illustrate these concepts using the groundwater modeling of a siliciclastic aquifer-fault system. The sources of uncertainty considered are from geological architecture, formation dip, boundary conditions and model parameters. The study shows that the HBMA analysis helps in advancing knowledge about the model rather than forcing the model to fit a particularly understanding or merely averaging several candidate models. [1] Tsai, F. T.-C., and A. S. Elshall (2013), Hierarchical Bayesian model averaging for hydrostratigraphic modeling: Uncertainty segregation and comparative evaluation. Water Resources Research, 49, 5520-5536, doi:10.1002/wrcr.20428. [2] Elshall, A.S., and F. T.-C. Tsai (2014). Constructive epistemic modeling of groundwater flow with geological architecture and boundary condition uncertainty under Bayesian paradigm, Journal of Hydrology, 517, 105-119, doi: 10.1016/j.jhydrol.2014.05.027.

  8. Process-Based Modeling of Constructed Wetlands

    Science.gov (United States)

    Baechler, S.; Brovelli, A.; Rossi, L.; Barry, D. A.

    2007-12-01

    Constructed wetlands (CWs) are widespread facilities for wastewater treatment. In subsurface flow wetlands, contaminated wastewater flows through a porous matrix, where oxidation and detoxification phenomena occur. Despite the large number of working CWs, system design and optimization are still mainly based upon empirical equations or simplified first-order kinetics. This results from an incomplete understanding of the system functioning, and may in turn hinder the performance and effectiveness of the treatment process. As a result, CWs are often considered not suitable to meet high water quality-standards, or to treat water contaminated with recalcitrant anthropogenic contaminants. To date, only a limited number of detailed numerical models have been developed and successfully applied to simulate constructed wetland behavior. Among these, one of the most complete and powerful is CW2D, which is based on Hydrus2D. The aim of this work is to develop a comprehensive simulator tailored to model the functioning of horizontal flow constructed wetlands and in turn provide a reliable design and optimization tool. The model is based upon PHWAT, a general reactive transport code for saturated flow. PHWAT couples MODFLOW, MT3DMS and PHREEQC-2 using an operator-splitting approach. The use of PHREEQC to simulate reactions allows great flexibility in simulating biogeochemical processes. The biogeochemical reaction network is similar to that of CW2D, and is based on the Activated Sludge Model (ASM). Kinetic oxidation of carbon sources and nutrient transformations (nitrogen and phosphorous primarily) are modeled via Monod-type kinetic equations. Oxygen dissolution is accounted for via a first-order mass-transfer equation. While the ASM model only includes a limited number of kinetic equations, the new simulator permits incorporation of an unlimited number of both kinetic and equilibrium reactions. Changes in pH, redox potential and surface reactions can be easily incorporated

  9. Constructing a systems psychodynamic wellness model

    Directory of Open Access Journals (Sweden)

    Sanchen Henning

    2012-03-01

    Research purpose: The purpose of the research was to construct and refine the SPWM in order to understand psychological wellness at the individual, group and organisational levels. Motivation for the study: There is no psychological wellness model that integrates the principles of systems psychodynamics and positive psychology. Systems psychodynamics traditionally focuses on so-called negative behaviour whilst positive psychology tends to idealise positive behaviour. This research tried to merge these views in order to apply them to individual, group and organisational behaviour. Research design, approach and method: The researchers used qualitative, descriptive and conceptual research. They conducted an in-depth literature study to construct the model. They then refined it using the LP. Main findings: The researchers identified 39 themes. They categorised them into three different levels. Three first-level themes emerged as the highest level of integration: identity, hope and love. The nine second-level themes each consisted of three more themes. They were less complex and abstract than the first-level themes. The least complex 27 third-level themes followed. Practical/managerial implications: One can apply the SPWM as a qualitative diagnostic tool for understanding individual, group and organisational wellness and for consulting on systemic wellness. Contribution/value-add: The SPWM offers a model for understanding individual, group and organisational wellness and for consulting on systemic wellness.

  10. Knowledge-based geometric modeling in construction

    DEFF Research Database (Denmark)

    Bonev, Martin; Hvam, Lars

    2012-01-01

    a considerably high amount of their recourses is required for designing and specifying the majority of their product assortment. As design decisions are hereby based on knowledge and experience about behaviour and applicability of construction techniques and materials for a predefined design situation, smart......A wider application of IT-based solutions, such as configuration systems and the implementation of modeling standards, has facilitated the trend to produce mass customized products to support inter alia the specification process of the increasing product variety. However, not all industries have...

  11. Reduced Order Electrostatic Force Field Modeling of 3D Spacecraft Shapes

    Data.gov (United States)

    National Aeronautics and Space Administration — The Autonomous Vehicles Systems (AVS) Lab at CU Boulder has been pursuing research in Coulomb charge control of spacecraft for several years. The electrostatic...

  12. Long-term orbit prediction for Tiangong-1 spacecraft using the mean atmosphere model

    Science.gov (United States)

    Tang, Jingshi; Liu, Lin; Cheng, Haowen; Hu, Songjie; Duan, Jianfeng

    2015-03-01

    China is planning to complete its first space station by 2020. For the long-term management and maintenance, the orbit of the space station needs to be predicted for a long period of time. Since the space station is expected to work in a low-Earth orbit, the error in the a priori atmosphere model contributes significantly to the rapid increase of the predicted orbit error. When the orbit is predicted for 20 days, the error in the a priori atmosphere model, if not properly corrected, could induce a semi-major axis error of up to a few kilometers and an overall position error of several thousand kilometers respectively. In this work, we use a mean atmosphere model averaged from NRLMSISE00. The a priori reference mean density can be corrected during the orbit determination. For the long-term orbit prediction, we use sufficiently long period of observations and obtain a series of the diurnal mean densities. This series contains the recent variation of the atmosphere density and can be analyzed for various periodic components. After being properly fitted, the mean density can be predicted and then applied in the orbit prediction. Here we carry out the test with China's Tiangong-1 spacecraft at the altitude of about 340 km and we show that this method is simple and flexible. The densities predicted with this approach can serve in the long-term orbit prediction. In several 20-day prediction tests, most predicted orbits show semi-major axis errors better than 700 m and overall position errors better than 400 km.

  13. Long-term orbit prediction for China's Tiangong-1 spacecraft based on mean atmosphere model

    Science.gov (United States)

    Tang, Jingshi; Liu, Lin; Miao, Manqian

    Tiangong-1 is China's test module for future space station. It has gone through three successful rendezvous and dockings with Shenzhou spacecrafts from 2011 to 2013. For the long-term management and maintenance, the orbit sometimes needs to be predicted for a long period of time. As Tiangong-1 works in a low-Earth orbit with an altitude of about 300-400 km, the error in the a priori atmosphere model contributes significantly to the rapid increase of the predicted orbit error. When the orbit is predicted for 10-20 days, the error in the a priori atmosphere model, if not properly corrected, could induce the semi-major axis error and the overall position error up to a few kilometers and several thousand kilometers respectively. In this work, we use a mean atmosphere model averaged from NRLMSIS00. The a priori reference mean density can be corrected during precise orbit determination (POD). For applications in the long-term orbit prediction, the observations are first accumulated. With sufficiently long period of observations, we are able to obtain a series of the diurnal mean densities. This series bears the recent variation of the atmosphere density and can be analyzed for various periods. After being properly fitted, the mean density can be predicted and then applied in the orbit prediction. We show that the densities predicted with this approach can serve to increase the accuracy of the predicted orbit. In several 20-day prediction tests, most predicted orbits show semi-major axis errors better than 700m and overall position errors better than 600km.

  14. Model-based software engineering for an optical navigation system for spacecraft

    Science.gov (United States)

    Franz, T.; Lüdtke, D.; Maibaum, O.; Gerndt, A.

    2018-06-01

    The project Autonomous Terrain-based Optical Navigation (ATON) at the German Aerospace Center (DLR) is developing an optical navigation system for future landing missions on celestial bodies such as the moon or asteroids. Image data obtained by optical sensors can be used for autonomous determination of the spacecraft's position and attitude. Camera-in-the-loop experiments in the Testbed for Robotic Optical Navigation (TRON) laboratory and flight campaigns with unmanned aerial vehicle (UAV) are performed to gather flight data for further development and to test the system in a closed-loop scenario. The software modules are executed in the C++ Tasking Framework that provides the means to concurrently run the modules in separated tasks, send messages between tasks, and schedule task execution based on events. Since the project is developed in collaboration with several institutes in different domains at DLR, clearly defined and well-documented interfaces are necessary. Preventing misconceptions caused by differences between various development philosophies and standards turned out to be challenging. After the first development cycles with manual Interface Control Documents (ICD) and manual implementation of the complex interactions between modules, we switched to a model-based approach. The ATON model covers a graphical description of the modules, their parameters and communication patterns. Type and consistency checks on this formal level help to reduce errors in the system. The model enables the generation of interfaces and unified data types as well as their documentation. Furthermore, the C++ code for the exchange of data between the modules and the scheduling of the software tasks is created automatically. With this approach, changing the data flow in the system or adding additional components (e.g., a second camera) have become trivial.

  15. Model-based software engineering for an optical navigation system for spacecraft

    Science.gov (United States)

    Franz, T.; Lüdtke, D.; Maibaum, O.; Gerndt, A.

    2017-09-01

    The project Autonomous Terrain-based Optical Navigation (ATON) at the German Aerospace Center (DLR) is developing an optical navigation system for future landing missions on celestial bodies such as the moon or asteroids. Image data obtained by optical sensors can be used for autonomous determination of the spacecraft's position and attitude. Camera-in-the-loop experiments in the Testbed for Robotic Optical Navigation (TRON) laboratory and flight campaigns with unmanned aerial vehicle (UAV) are performed to gather flight data for further development and to test the system in a closed-loop scenario. The software modules are executed in the C++ Tasking Framework that provides the means to concurrently run the modules in separated tasks, send messages between tasks, and schedule task execution based on events. Since the project is developed in collaboration with several institutes in different domains at DLR, clearly defined and well-documented interfaces are necessary. Preventing misconceptions caused by differences between various development philosophies and standards turned out to be challenging. After the first development cycles with manual Interface Control Documents (ICD) and manual implementation of the complex interactions between modules, we switched to a model-based approach. The ATON model covers a graphical description of the modules, their parameters and communication patterns. Type and consistency checks on this formal level help to reduce errors in the system. The model enables the generation of interfaces and unified data types as well as their documentation. Furthermore, the C++ code for the exchange of data between the modules and the scheduling of the software tasks is created automatically. With this approach, changing the data flow in the system or adding additional components (e.g., a second camera) have become trivial.

  16. Constructing Agent Model for Virtual Training Systems

    Science.gov (United States)

    Murakami, Yohei; Sugimoto, Yuki; Ishida, Toru

    Constructing highly realistic agents is essential if agents are to be employed in virtual training systems. In training for collaboration based on face-to-face interaction, the generation of emotional expressions is one key. In training for guidance based on one-to-many interaction such as direction giving for evacuations, emotional expressions must be supplemented by diverse agent behaviors to make the training realistic. To reproduce diverse behavior, we characterize agents by using a various combinations of operation rules instantiated by the user operating the agent. To accomplish this goal, we introduce a user modeling method based on participatory simulations. These simulations enable us to acquire information observed by each user in the simulation and the operating history. Using these data and the domain knowledge including known operation rules, we can generate an explanation for each behavior. Moreover, the application of hypothetical reasoning, which offers consistent selection of hypotheses, to the generation of explanations allows us to use otherwise incompatible operation rules as domain knowledge. In order to validate the proposed modeling method, we apply it to the acquisition of an evacuee's model in a fire-drill experiment. We successfully acquire a subject's model corresponding to the results of an interview with the subject.

  17. Maturity and maturity models in lean construction

    Directory of Open Access Journals (Sweden)

    Claus Nesensohn

    2014-03-01

    Full Text Available In recent years there has been an increasing interest in maturity models in management-related disciplines; which reflects a growing recognition that becoming more mature and having a model to guide the route to maturity can help organisations in managing major transformational change. Lean Construction (LC is an increasingly important improvement approach that organisations seek to embed. This study explores how to apply the maturity models to LC. Hence the attitudes, opinions and experiences of key industry informants with high levels of knowledge of LC were investigated. To achieve this, a review of maturity models was conducted, and data for the analysis was collected through a sequential process involving three methods. First a group interview with seven key informants. Second a follow up discussion with the same individuals to investigate some of the issues raised in more depth. Third an online discussion held via LinkedIn in which members shared their views on some of the results. Overall, we found that there is a lack of common understanding as to what maturity means in LC, though there is general agreement that the concept of maturity is a suitable one to reflect the path of evolution for LC within organisations.

  18. Global modeling of flux transfer events: generation mechanism and spacecraft signatures

    Science.gov (United States)

    Raeder, J.

    2003-04-01

    Magnetic reconnection is a fundamental mode of energy and momentum transfer from the solar wind to the magnetosphere. It is known to occur in different forms depending on solar wind and magnetospheric conditions. In particular, steady reconnection can be distinguished from pulse-like reconnection events which are also known as Flux Transfer Events (FTEs). The formation mechanism of FTEs and their contolling factors remain controversial. We use global MHD simulations of Earth's magnetosphere to show that for southward IMF conditions: a) steady reconnection preferentially occurs without FTEs when the stagnation flow line nearly coincides with the X-line location, which requires small dipole tilt and nearly due southward IMF, b) FTEs occur when the flow/field symmetry is broken, which requires either a large dipole tilt and/or a substantial east-west component of the IMF, c) the predicted spacecraft signature and the repetition frequency of FTEs in the simulations agrees very well with typical observations, lending credibility to the the model, d) the fundamental process that leads to FTE formation is multiple X-line formation caused by the flow and field patterns in the magnetosheath and requires no intrinsic plasma property variations like variable resistivity, e) if the dipole tilt breaks the symmetry FTEs occur only in the winter hemisphere whereas the reconnection signatures in the summer hemisphere are steady with no bipolar FTE-like signatures, f) if the IMF east-west field component breaks the symmetry FTEs occur in both hemispheres, and g) FTE formation depends on sufficient resolution and low diffusion in the model -- coarse resolution and/or high diffusivity lead to flow-through reconnection signatures that appear unphysical given the frequent observation of FTEs.

  19. Constructing Dynamic Event Trees from Markov Models

    International Nuclear Information System (INIS)

    Paolo Bucci; Jason Kirschenbaum; Tunc Aldemir; Curtis Smith; Ted Wood

    2006-01-01

    In the probabilistic risk assessment (PRA) of process plants, Markov models can be used to model accurately the complex dynamic interactions between plant physical process variables (e.g., temperature, pressure, etc.) and the instrumentation and control system that monitors and manages the process. One limitation of this approach that has prevented its use in nuclear power plant PRAs is the difficulty of integrating the results of a Markov analysis into an existing PRA. In this paper, we explore a new approach to the generation of failure scenarios and their compilation into dynamic event trees from a Markov model of the system. These event trees can be integrated into an existing PRA using software tools such as SAPHIRE. To implement our approach, we first construct a discrete-time Markov chain modeling the system of interest by: (a) partitioning the process variable state space into magnitude intervals (cells), (b) using analytical equations or a system simulator to determine the transition probabilities between the cells through the cell-to-cell mapping technique, and, (c) using given failure/repair data for all the components of interest. The Markov transition matrix thus generated can be thought of as a process model describing the stochastic dynamic behavior of the finite-state system. We can therefore search the state space starting from a set of initial states to explore all possible paths to failure (scenarios) with associated probabilities. We can also construct event trees of arbitrary depth by tracing paths from a chosen initiating event and recording the following events while keeping track of the probabilities associated with each branch in the tree. As an example of our approach, we use the simple level control system often used as benchmark in the literature with one process variable (liquid level in a tank), and three control units: a drain unit and two supply units. Each unit includes a separate level sensor to observe the liquid level in the tank

  20. 874 CONSTRUCTION COST MODELS FOR HIGHRISE OFFICE ...

    African Journals Online (AJOL)

    USER

    2015-10-28

    Oct 28, 2015 ... will not only reduce the stress on estimators but also enhance the accuracy of cost estimates. The resulting 11 ... cost estimating process to work together to ..... construction estimators in Hong. Kong. Construction Management.

  1. Constructive Empiricism and Model Nominalism. | Udokang | Sophia ...

    African Journals Online (AJOL)

    James Ladyman has argued that constructive empiricism entails modal realism, and that this renders constructive empiricism untenable. We maintain that constructive empiricism is compatible with modal nominalism. Although the central term “observable” has been analyzed in terms of counterfactuals, and in general ...

  2. Assessment of the Forward Contamination Risk of Mars by Clean Room Isolates from Space-Craft Assembly Facilities through Aeolian Transport - a Model Study

    Science.gov (United States)

    van Heereveld, Luc; Merrison, Jonathan; Nørnberg, Per; Finster, Kai

    2017-06-01

    The increasing number of missions to Mars also increases the risk of forward contamination. Consequently there is a need for effective protocols to ensure efficient protection of the Martian environment against terrestrial microbiota. Despite the fact of constructing sophisticated clean rooms for spacecraft assembly a 100 % avoidance of contamination appears to be impossible. Recent surveys of these facilities have identified a significant number of microbes belonging to a variety of taxonomic groups that survive the harsh conditions of clean rooms. These microbes may have a strong contamination potential, which needs to be investigate to apply efficient decontamination treatments. In this study we propose a series of tests to evaluate the potential of clean room contaminants to survive the different steps involved in forward contamination. We used Staphylococcus xylosus as model organism to illustrate the different types of stress that potential contaminants will be subjected to on their way from the spacecraft onto the surface of Mars. Staphylococcus xylosus is associated with human skin and commonly found in clean rooms and could therefore contaminate the spacecraft as a result of human activity during the assembling process. The path the cell will take from the surface of the spacecraft onto the surface of Mars was split into steps representing different stresses that include desiccation, freezing, aeolian transport in a Martian-like atmosphere at Martian atmospheric pressure, and UV radiation climate. We assessed the surviving fraction of the cellular population after each step by determining the integrated metabolic activity of the survivor population by measuring their oxygen consumption rate. The largest fraction of the starting culture (around 70 %) was killed during desiccation, while freezing, Martian vacuum and short-term UV radiation only had a minor additional effect on the survivability of Staphylococcus xylosus. The study also included a simulation

  3. Model Tests on the Retaining Walls Constructed from Geobags Filled with Construction Waste

    OpenAIRE

    Wen, Hua; Wu, Jiu-jiang; Zou, Jiao-li; Luo, Xin; Zhang, Min; Gu, Chengzhuang

    2016-01-01

    Geobag retaining wall using construction waste is a new flexible supporting structure, and the usage of construction waste to fill geobags can facilitate the construction recycling. In this paper, model tests were performed on geobag retaining wall using construction waste. The investigation was concentrated on the slope top settlement, the distribution characteristics of the earth pressures on retaining walls and horizontal wall displacements, and slope failure modes. The results indicated t...

  4. Potential and Benefits of Building Information Modeling (BIM During Pre-Construction, Construction and Post Construction Stage

    Directory of Open Access Journals (Sweden)

    Aw Nien Wei

    2017-11-01

    Full Text Available The construction industry is the main economic support for all countries around the world in which continually adapting to meet competitive challenges around the global market. Nevertheless, the construction project is becoming much more complex and difficult to manage. This is because the construction project involves a large number of stakeholder, for example, the consultant companies, architects, engineers, building surveyors and quantity surveyors. The technology currently used in the construction industry is the AutoCAD (Automatic computeraided design. AutoCAD is a commercial software application for 2D and 3D computer-aided design (CAD and drafting develop by Autodesk. Generally, all the drawing design from Autocad will be exchanged among the stakeholder in the form of paper. Information exchanged among them mostly involves a lot of documents and drawings. This practice creates errors because of documents and drawings are mostly in a paper-based format that is not properly managed which results in miscommunication among them. Having wrong information in the construction process could hinder the productivity of projects because in a construction project information is one of the important construction materials. Building Information Modeling (BIM is one of the newly software in the architecture, engineering, and construction (AEC industries to ensure all parties receive the right information. BIM technology is also an intelligent model of a building constructed digitally in the way of 3D. The software will generate model containing the information needed to support the construction, fabrication, and procurement activities that needed to realize the building. This paper will discuss on potential and benefits of BIM during pre-construction stage, construction stage and during post construction stage

  5. A diagrammatic construction of formal E-independent model hamiltonian

    International Nuclear Information System (INIS)

    Kvasnicka, V.

    1977-01-01

    A diagrammatic construction of formal E-independent model interaction (i.e., without second-quantization formalism) is suggested. The construction starts from the quasi-degenerate Brillouin-Wigner perturbation theory, in the framework of which an E-dependent model Hamiltonian is simply constructed. Applying the ''E-removing'' procedure to this E-dependent model Hamiltonian, the E-independent formal model Hamiltonian either Hermitian or non-Hermitian can diagrammatically be easily derived. For the formal E-independent model Hamiltonian the separability theorem is proved, which can be profitably used for a rather ''formalistic ''construction of a many-body E-independent model Hamiltonian

  6. REQUIREMENTS FOR IMAGE QUALITY OF EMERGENCY SPACECRAFTS

    Directory of Open Access Journals (Sweden)

    A. I. Altukhov

    2015-05-01

    Full Text Available The paper deals with the method for formation of quality requirements to the images of emergency spacecrafts. The images are obtained by means of remote sensing of near-earth space orbital deployment in the visible range. of electromagnetic radiation. The method is based on a joint taking into account conditions of space survey, characteristics of surveillance equipment, main design features of the observed spacecrafts and orbital inspection tasks. Method. Quality score is the predicted linear resolution image that gives the possibility to create a complete view of pictorial properties of the space image obtained by electro-optical system from the observing satellite. Formulation of requirements to the numerical value of this indicator is proposed to perform based on the properties of remote sensing system, forming images in the conditions of outer space, and the properties of the observed emergency spacecraft: dimensions, platform construction of the satellite, on-board equipment placement. For method implementation the authors have developed a predictive model of requirements to a linear resolution for images of emergency spacecrafts, making it possible to select the intervals of space shooting and get the satellite images required for quality interpretation. Main results. To verify the proposed model functionality we have carried out calculations of the numerical values for the linear resolution of the image, ensuring the successful task of determining the gross structural damage of the spacecrafts and identifying changes in their spatial orientation. As input data were used with dimensions and geometric primitives corresponding to the shape of deemed inspected spacecrafts: Resurs-P", "Canopus-B", "Electro-L". Numerical values of the linear resolution images have been obtained, ensuring the successful task solution for determining the gross structural damage of spacecrafts.

  7. Elaboration of technology organizational models of constructing high-rise buildings in plans of construction organization

    Science.gov (United States)

    Osipenkova, Irina; Simankina, Tatyana; Syrygina, Taisiia; Lukinov, Vitaliy

    2018-03-01

    This article represents features of the elaboration of technology organizational models of high-rise building construction in technology organizational documentation on the example of the plan of construction organization. Some examples of enhancing the effectiveness of high-rise building construction based on developments of several options of the organizational and technological plan are examined. Qualitative technology organizational documentation allows to increase the competitiveness of construction companies and provides prime cost of construction and assembly works reductions. Emphasis is placed on the necessity to comply with the principle of comprehensiveness of engineering, scientific and research works, development activities and scientific and technical support.

  8. Modelling the reflective thermal contribution to the acceleration of the Pioneer spacecraft

    Energy Technology Data Exchange (ETDEWEB)

    Francisco, F., E-mail: frederico.francisco@ist.utl.pt [Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Bertolami, O., E-mail: orfeu.bertolami@fc.up.pt [Departamento de Fisica e Astronomia, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Gil, P.J.S., E-mail: p.gil@dem.ist.utl.pt [Departamento de Engenharia Mecanica and IDMEC - Instituto de Engenharia Mecanica, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Paramos, J., E-mail: paramos@ist.edu [Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal)

    2012-05-23

    We present an improved method to compute the radiative momentum transfer in the Pioneer 10 and 11 spacecraft that takes into account both diffusive and specular reflection. The method allows for more reliable results regarding the thermal acceleration of the deep-space probes, confirming previous findings. A parametric analysis is performed in order to set upper and lower bounds for the thermal acceleration and its evolution with time.

  9. Modelling the reflective thermal contribution to the acceleration of the Pioneer spacecraft

    International Nuclear Information System (INIS)

    Francisco, F.; Bertolami, O.; Gil, P.J.S.; Páramos, J.

    2012-01-01

    We present an improved method to compute the radiative momentum transfer in the Pioneer 10 and 11 spacecraft that takes into account both diffusive and specular reflection. The method allows for more reliable results regarding the thermal acceleration of the deep-space probes, confirming previous findings. A parametric analysis is performed in order to set upper and lower bounds for the thermal acceleration and its evolution with time.

  10. Construction Worker Fatigue Prediction Model Based on System Dynamic

    Directory of Open Access Journals (Sweden)

    Wahyu Adi Tri Joko

    2017-01-01

    Full Text Available Construction accident can be caused by internal and external factors such as worker fatigue and unsafe project environment. Tight schedule of construction project forcing construction worker to work overtime in long period. This situation leads to worker fatigue. This paper proposes a model to predict construction worker fatigue based on system dynamic (SD. System dynamic is used to represent correlation among internal and external factors and to simulate level of worker fatigue. To validate the model, 93 construction workers whom worked in a high rise building construction projects, were used as case study. The result shows that excessive workload, working elevation and age, are the main factors lead to construction worker fatigue. Simulation result also shows that these factors can increase worker fatigue level to 21.2% times compared to normal condition. Beside predicting worker fatigue level this model can also be used as early warning system to prevent construction worker accident

  11. Modeling Attitude Dynamics in Simulink: A Study of the Rotational and Translational Motion of a Spacecraft Given Torques and Impulses Generated by RMS Hand Controllers

    Science.gov (United States)

    Mauldin, Rebecca H.

    2010-01-01

    In order to study and control the attitude of a spacecraft, it is necessary to understand the natural motion of a body in orbit. Assuming a spacecraft to be a rigid body, dynamics describes the complete motion of the vehicle by the translational and rotational motion of the body. The Simulink Attitude Analysis Model applies the equations of rigid body motion to the study of a spacecraft?s attitude in orbit. Using a TCP/IP connection, Matlab reads the values of the Remote Manipulator System (RMS) hand controllers and passes them to Simulink as specified torque and impulse profiles. Simulink then uses the governing kinematic and dynamic equations of a rigid body in low earth orbit (LE0) to plot the attitude response of a spacecraft for five seconds given known applied torques and impulses, and constant principal moments of inertia.

  12. Multibody dynamical modeling for spacecraft docking process with spring-damper buffering device: A new validation approach

    Science.gov (United States)

    Daneshjou, Kamran; Alibakhshi, Reza

    2018-01-01

    In the current manuscript, the process of spacecraft docking, as one of the main risky operations in an on-orbit servicing mission, is modeled based on unconstrained multibody dynamics. The spring-damper buffering device is utilized here in the docking probe-cone system for micro-satellites. Owing to the impact occurs inevitably during docking process and the motion characteristics of multibody systems are remarkably affected by this phenomenon, a continuous contact force model needs to be considered. Spring-damper buffering device, keeping the spacecraft stable in an orbit when impact occurs, connects a base (cylinder) inserted in the chaser satellite and the end of docking probe. Furthermore, by considering a revolute joint equipped with torsional shock absorber, between base and chaser satellite, the docking probe can experience both translational and rotational motions simultaneously. Although spacecraft docking process accompanied by the buffering mechanisms may be modeled by constrained multibody dynamics, this paper deals with a simple and efficient formulation to eliminate the surplus generalized coordinates and solve the impact docking problem based on unconstrained Lagrangian mechanics. By an example problem, first, model verification is accomplished by comparing the computed results with those recently reported in the literature. Second, according to a new alternative validation approach, which is based on constrained multibody problem, the accuracy of presented model can be also evaluated. This proposed verification approach can be applied to indirectly solve the constrained multibody problems by minimum required effort. The time history of impact force, the influence of system flexibility and physical interaction between shock absorber and penetration depth caused by impact are the issues followed in this paper. Third, the MATLAB/SIMULINK multibody dynamic analysis software will be applied to build impact docking model to validate computed results and

  13. Modelling the factors influencing the selection of the construction equipment for Indian construction organizations

    Directory of Open Access Journals (Sweden)

    S.V.S. Raja Prasad

    2016-09-01

    Full Text Available The contribution of Indian construction sector to the GDP is approximately 10%. Under new government policy, it is anticipated that $1000 Billion share for exclusively infrastructure segment would be completed within the next few years. Construction sector in developing country like India still depends on labor and the practice of mechanization, adopting to use of versatile construction equipment is not in force. The need for implementing new technologies and automation is essential to improve the quality, safety and efficiency. To meet the challenges ahead the construction, organizations should focus on utilization of machinery/equipment to achieve desirable results. Modern construction is characterized by the increase in utilization of equipment to accomplish numerous construction activities. The selection of construction equipment often affects the required amount of time and effort. It is therefore important for managements of construction organizations and planners to be familiar with the features of various types of equipment commonly used in construction activities. The selection of appropriate equipment is a crucial decision making process as it involves huge capital investment. The purpose of the present study is to develop a model pertaining to the factors influencing the selection of construction equipment by using interpretive structural modelling and the results indicate that productivity and safety are the important factors in selection of equipment in Indian construction organizations.

  14. A Preliminary Model for Spacecraft Propulsion Performance Analysis Based on Nuclear Gain and Subsystem Mass-Power Balances

    Science.gov (United States)

    Chakrabarti, Suman; Schmidt, George R.; Thio, Y. C.; Hurst, Chantelle M.

    1999-01-01

    A preliminary model for spacecraft propulsion performance analysis based on nuclear gain and subsystem mass-power balances are presented in viewgraph form. For very fast missions with straight-line trajectories, it has been shown that mission trip time is proportional to the cube root of alpha. Analysis of spacecraft power systems via a power balance and examination of gain vs. mass-power ratio has shown: 1) A minimum gain is needed to have enough power for thruster and driver operation; and 2) Increases in gain result in decreases in overall mass-power ratio, which in turn leads to greater achievable accelerations. However, subsystem mass-power ratios and efficiencies are crucial: less efficient values for these can partially offset the effect of nuclear gain. Therefore, it is of interest to monitor the progress of gain-limited subsystem technologies and it is also possible that power-limited systems with sufficiently low alpha may be competitive for such ambitious missions. Topics include Space flight requirements; Spacecraft energy gain; Control theory for performance; Mission assumptions; Round trips: Time and distance; Trip times; Vehicle acceleration; and Minimizing trip times.

  15. Product models for the Construction industry

    DEFF Research Database (Denmark)

    Sørensen, Lars Schiøtt

    1996-01-01

    Different types of product models for the building sector was elaborated and grouped. Some discussion on the different models was given. The "definition" of Product models was given.......Different types of product models for the building sector was elaborated and grouped. Some discussion on the different models was given. The "definition" of Product models was given....

  16. Construction project investment control model based on instant information

    Institute of Scientific and Technical Information of China (English)

    WANG Xue-tong

    2006-01-01

    Change of construction conditions always influences project investment by causing the loss of construction work time and extending the duration. To resolve such problem as difficult dynamic control in work construction plan, this article presents a concept of instant optimization by ways of adjustment operation time of each working procedure to minimize investment change. Based on this concept, its mathematical model is established and a strict mathematical justification is performed. An instant optimization model takes advantage of instant information in the construction process to duly complete adjustment of construction; thus we maximize cost efficiency of project investment.

  17. Construction Worker Fatigue Prediction Model Based on System Dynamic

    OpenAIRE

    Wahyu Adi Tri Joko; Ayu Ratnawinanda Lila

    2017-01-01

    Construction accident can be caused by internal and external factors such as worker fatigue and unsafe project environment. Tight schedule of construction project forcing construction worker to work overtime in long period. This situation leads to worker fatigue. This paper proposes a model to predict construction worker fatigue based on system dynamic (SD). System dynamic is used to represent correlation among internal and external factors and to simulate level of worker fatigue. To validate...

  18. Modelling verb selection within argument structure constructions

    NARCIS (Netherlands)

    Matusevych, Yevgen; Alishahi, Afra; Backus, Albert

    2017-01-01

    This article looks into the nature of cognitive associations between verbs and argument structure constructions (ASCs). Existing research has shown that distributional and semantic factors affect speakers' choice of verbs in ASCs. A formal account of this theory has been proposed by Ellis,

  19. MULTI-SPACECRAFT OBSERVATIONS AND TRANSPORT MODELING OF ENERGETIC ELECTRONS FOR A SERIES OF SOLAR PARTICLE EVENTS IN AUGUST 2010

    Energy Technology Data Exchange (ETDEWEB)

    Dröge, W.; Kartavykh, Y. Y. [Institut für Theoretische Physik und Astrophysik, Universität Würzburg, D-97074 Würzburg (Germany); Dresing, N.; Klassen, A. [Institut für Experimentelle und Angewandte Physik, Universität Kiel, D-24118 Kiel (Germany)

    2016-08-01

    During 2010 August a series of solar particle events was observed by the two STEREO spacecraft as well as near-Earth spacecraft. The events, occurring on August 7, 14, and 18, originated from active regions 11093 and 11099. We combine in situ and remote-sensing observations with predictions from our model of three-dimensional anisotropic particle propagation in order to investigate the physical processes that caused the large angular spreads of energetic electrons during these events. In particular, we address the effects of the lateral transport of the electrons in the solar corona that is due to diffusion perpendicular to the average magnetic field in the interplanetary medium. We also study the influence of two coronal mass ejections and associated shock waves on the electron propagation, and a possible time variation of the transport conditions during the above period. For the August 18 event we also utilize electron observations from the MESSENGER spacecraft at a distance of 0.31 au from the Sun for an attempt to separate between radial and longitudinal dependencies in the transport process. Our modelings show that the parallel and perpendicular diffusion mean free paths of electrons can vary significantly not only as a function of the radial distance, but also of the heliospheric longitude. Normalized to a distance of 1 au, we derive values of λ {sub ∥} in the range of 0.15–0.6 au, and values of λ {sub ⊥} in the range of 0.005–0.01 au. We discuss how our results relate to various theoretical models for perpendicular diffusion, and whether there might be a functional relationship between the perpendicular and the parallel mean free path.

  20. Polyether sulfone membrane modeling and construction for the ...

    African Journals Online (AJOL)

    Polyether sulfone membrane modeling and construction for the removal of nitrate from water using ion interference sulfate and iron nano-particle. ... The aim of this study was constructed the polyether sulfone membrane and modelling it, and for checking impact pressure, the amount of iron nanoparticles and sulfate iron ...

  1. Spacecraft operations

    CERN Document Server

    Sellmaier, Florian; Schmidhuber, Michael

    2015-01-01

    The book describes the basic concepts of spaceflight operations, for both, human and unmanned missions. The basic subsystems of a space vehicle are explained in dedicated chapters, the relationship of spacecraft design and the very unique space environment are laid out. Flight dynamics are taught as well as ground segment requirements. Mission operations are divided into preparation including management aspects, execution and planning. Deep space missions and space robotic operations are included as special cases. The book is based on a course held at the German Space Operation Center (GSOC).

  2. Knowledge-Based Decision Model Construction for Dynamic Interpretation Tasks

    National Research Council Canada - National Science Library

    Wellman, Michael

    1997-01-01

    ...) is highly variable, precluding specification of a fixed model in advance. The project yielded technical results in four areas of reasoning and decision making under uncertainty involving model construction: (1...

  3. Cloud model construct for transaction-based cooperative systems ...

    African Journals Online (AJOL)

    Cloud model construct for transaction-based cooperative systems. ... procure cutting edge Information Technology infrastructure are some of the problems faced ... Results also reveal that credit cooperatives will benefit from the model by taking ...

  4. Business model reconfiguration in green construction: A theoretical perspective

    OpenAIRE

    Abuzeinab, Amal; Arif, Mohammed

    2013-01-01

    PhD study Business models describe the business logic of a particular company and green business model is when a company changes part(s) of its business model and thereby both captures economic value and reduces the ecological footprint in a life-cycle perspective. In this paper, business model literature is reviewed with the intention of promoting learning to understand the economic complexity of environmental sustainability in the construction context. Although the green construction lit...

  5. Masonry constructions mechanical models and numerical applications

    CERN Document Server

    Lucchesi, Massimiliano; Padovani, Cristina

    2008-01-01

    Numerical methods for the structural analysis of masonry constructions can be of great value in assessing the safety of artistically important masonry buildings and optimizing potential operations of maintenance and strengthening in terms of their cost-effectiveness, architectural impact and static effectiveness. This monograph firstly provides a detailed description of the constitutive equation of masonry-like materials, clearly setting out its most important features. It then goes on to provide a numerical procedure to solve the equilibrium problem of masonry solids. A large portion of the w

  6. 4D modeling in high-rise construction

    Science.gov (United States)

    Balakina, Anastasiya; Simankina, Tatyana; Lukinov, Vitaly

    2018-03-01

    High-rise construction is a complex construction process, requiring the use of more perfected and sophisticated tools for design, planning and construction management. The use of BIM-technologies allows minimizing the risks associated with design errors and errors that occur during construction. This article discusses a visual planning method using the 4D model, which allows the project team to create an accurate and complete construction plan, which is much more difficult to achieve with the help of traditional planning methods. The use of the 4D model in the construction of a 70-story building allowed to detect spatial and temporal errors before the start of construction work. In addition to identifying design errors, 4D modeling has allowed to optimize the construction, as follows: to optimize the operation of cranes, the placement of building structures and materials at various stages of construction, to optimize the organization of work performance, as well as to monitor the activities related to the preparation of the construction site for compliance with labor protection and safety requirements, which resulted in saving money and time.

  7. 4D modeling in high-rise construction

    Directory of Open Access Journals (Sweden)

    Balakina Anastasiya

    2018-01-01

    Full Text Available High-rise construction is a complex construction process, requiring the use of more perfected and sophisticated tools for design, planning and construction management. The use of BIM-technologies allows minimizing the risks associated with design errors and errors that occur during construction. This article discusses a visual planning method using the 4D model, which allows the project team to create an accurate and complete construction plan, which is much more difficult to achieve with the help of traditional planning methods. The use of the 4D model in the construction of a 70-story building allowed to detect spatial and temporal errors before the start of construction work. In addition to identifying design errors, 4D modeling has allowed to optimize the construction, as follows: to optimize the operation of cranes, the placement of building structures and materials at various stages of construction, to optimize the organization of work performance, as well as to monitor the activities related to the preparation of the construction site for compliance with labor protection and safety requirements, which resulted in saving money and time.

  8. Spacecraft Attitude Determination

    DEFF Research Database (Denmark)

    Bak, Thomas

    This thesis describes the development of an attitude determination system for spacecraft based only on magnetic field measurements. The need for such system is motivated by the increased demands for inexpensive, lightweight solutions for small spacecraft. These spacecraft demands full attitude...... determination based on simple, reliable sensors. Meeting these objectives with a single vector magnetometer is difficult and requires temporal fusion of data in order to avoid local observability problems. In order to guaranteed globally nonsingular solutions, quaternions are generally the preferred attitude...... is a detailed study of the influence of approximations in the modeling of the system. The quantitative effects of errors in the process and noise statistics are discussed in detail. The third contribution is the introduction of these methods to the attitude determination on-board the Ørsted satellite...

  9. Locally Simple Models Construction: Methodology and Practice

    Directory of Open Access Journals (Sweden)

    I. A. Kazakov

    2017-12-01

    Full Text Available One of the most notable trends associated with the Fourth industrial revolution is a significant strengthening of the role played by semantic methods. They are engaged in artificial intelligence means, knowledge mining in huge flows of big data, robotization, and in the internet of things. Smart contracts also can be mentioned here, although the ’intelligence’ of smart contracts still needs to be seriously elaborated. These trends should inevitably lead to an increased role of logical methods working with semantics, and significantly expand the scope of their application in practice. However, there are a number of problems that hinder this process. We are developing an approach, which makes the application of logical modeling efficient in some important areas. The approach is based on the concept of locally simple models and is primarily focused on solving tasks in the management of enterprises, organizations, governing bodies. The most important feature of locally simple models is their ability to replace software systems. Replacement of programming by modeling gives huge advantages, for instance, it dramatically reduces development and support costs. Modeling, unlike programming, preserves the explicit semantics of models allowing integration with artificial intelligence and robots. In addition, models are much more understandable to general people than programs. In this paper we propose the implementation of the concept of locally simple modeling on the basis of so-called document models, which has been developed by us earlier. It is shown that locally simple modeling is realized through document models with finite submodel coverages. In the second part of the paper an example of using document models for solving a management problem of real complexity is demonstrated.

  10. Constructive modelling of structural turbulence: computational experiment

    Energy Technology Data Exchange (ETDEWEB)

    Belotserkovskii, O M; Oparin, A M; Troshkin, O V [Institute for Computer Aided Design, Russian Academy of Sciences, Vtoraya Brestskaya st., 19/18, Moscow, 123056 (Russian Federation); Chechetkin, V M [Keldysh Institute for Applied Mathematics, Russian Academy of Sciences, Miusskaya sq., 4, Moscow, 125047 (Russian Federation)], E-mail: o.bel@icad.org.ru, E-mail: a.oparin@icad.org.ru, E-mail: troshkin@icad.org.ru, E-mail: chech@gin@keldysh.ru

    2008-12-15

    Constructively, the analysis of the phenomenon of turbulence must and can be performed through direct numerical simulations of mechanics supposed to be inherent to secondary flows. This one reveals itself through such instances as large vortices, structural instabilities, vortex cascades and principal modes discussed in this paper. Like fragments of a puzzle, they speak of a motion ordered with its own nuts and bolts, however chaotic it appears at first sight. This opens an opportunity for a multi-oriented approach of which a prime ideology seems to be a rational combination of grid, spectral and statistical methods. An attempt is made to bring together the above instances and produce an alternative point of view on the phenomenon in question when based on the main laws of conservation.

  11. Construction of closed fermionic string models in four dimensions

    International Nuclear Information System (INIS)

    Lewellen, D.C.

    1987-01-01

    It is possible to construct consistent closed string models directly in four space-time dimensions if reparametrization invariance, conformal invariance and world sheet supersymmetry are properly accounted for. In the context of string models whose internal degrees of freedom are represented by free world sheet fermions, it is possible to completely solve for the above requirements, providing a simple set of rules for constructing string models. N = 1 supersymmetric and non-supersymmetric heterotic type string models with chiral fermions and realistic gauge groups, as well as generalized type II models with realistic gauge groups, can easily be constructed. Many other string models can be constructed using similar methods based on free world sheet bosons

  12. Construction cost forecast model : model documentation and technical notes.

    Science.gov (United States)

    2013-05-01

    Construction cost indices are generally estimated with Laspeyres, Paasche, or Fisher indices that allow changes : in the quantities of construction bid items, as well as changes in price to change the cost indices of those items. : These cost indices...

  13. Introduction of Building Information Modeling (BIM) Technologies in Construction

    Science.gov (United States)

    Milyutina, M. A.

    2018-05-01

    The issues of introduction of building information modeling (BIM) in construction industry are considered in this work. The advantages of this approach and perspectives of the transition to new design technologies, construction process management, and operation in the near future are stated. The importance of development of pilot projects that should identify the ways and means of verification of the regulatory and technical base, as well as economic indicators in the transition to Building Information Technologies in the construction, is noted.

  14. Constructing Pedagogical Models For E-learning

    OpenAIRE

    Patricia Alejandra Behar

    2011-01-01

    This article brings forth an overview of the paradigmatic crisis and the introduction of new pedagogical practices. It also discusses the relationship between paradigm and pedagogical model, presenting a theoretical discussion on the concepts of pedagogical model for E-learning and its pedagogical architecture. To do so, the elements that are part of it such as organizational aspects, content, methodological and technological aspects are discussed. This theoretical discussion underlies the co...

  15. Modeling the Constructs Contributing to the Effectiveness of Marketing Lecturers

    Science.gov (United States)

    Sweeney, Arthur D. P.; Morrison, Mark D.; Jarratt, Denise; Heffernan, Troy

    2009-01-01

    Student evaluation of teaching has been examined in higher education research for over 70 years but there are gaps in our knowledge about the contribution, and relationships between, the relevant constructs. Recent literature encourages researchers to test multivariate models of Teaching Effectiveness. Seven main constructs known to influence…

  16. Methods and models for the construction of weakly parallel tests

    NARCIS (Netherlands)

    Adema, J.J.; Adema, Jos J.

    1992-01-01

    Several methods are proposed for the construction of weakly parallel tests [i.e., tests with the same test information function (TIF)]. A mathematical programming model that constructs tests containing a prespecified TIF and a heuristic that assigns items to tests with information functions that are

  17. Methods and models for the construction of weakly parallel tests

    NARCIS (Netherlands)

    Adema, J.J.; Adema, Jos J.

    1990-01-01

    Methods are proposed for the construction of weakly parallel tests, that is, tests with the same test information function. A mathematical programing model for constructing tests with a prespecified test information function and a heuristic for assigning items to tests such that their information

  18. Review of constructive models for concrete

    International Nuclear Information System (INIS)

    Xiaoping, Y.; Ottosen, N.S.; Thelandersson, S.; Nielsen, M.P.

    1989-11-01

    This report has been prepared for the Commission of the European Communities, Joint Research Centre, ISPRA. The report reviews the constitutive models for concrete and is a part of a survey of the status of the analytical capabilities for predicting the structural response of NPP concrete containment buildings to severe loading conditions

  19. Anthropomimetic Robots: Concept, Construction and Modelling

    Directory of Open Access Journals (Sweden)

    Alan Diamond

    2012-11-01

    Full Text Available An anthropomimetic robot is one that closely copies the mechanics of the human body by having a human-like jointed skeleton moved by compliant muscle-like actuators. This paper describes the progress achieved in building anthropomimetic torsos in two projects, CRONOS and ECCEROBOT. In each, the bones were hand-moulded in a thermoplastic and the muscles were implemented by DC motors shortening and extending elastic tendons. Anthropomimetic robots differ from conventionally engineered robots by having complex joints and compliant tendon driven actuation that can cross more than one joint. Taken together, these characteristics make the robots unsuitable for control by standard methods, and so the ability to model them is important for developing heuristic methods of control and also for providing forward models. The robots were modelled using physics-based techniques which enable the study of the generation of movements and also of interactions with arbitrary objects. The lightweight and compliant structure of the robots was found to be safe for human proximity and contact.

  20. Modeling protein structures: construction and their applications.

    Science.gov (United States)

    Ring, C S; Cohen, F E

    1993-06-01

    Although no general solution to the protein folding problem exists, the three-dimensional structures of proteins are being successfully predicted when experimentally derived constraints are used in conjunction with heuristic methods. In the case of interleukin-4, mutagenesis data and CD spectroscopy were instrumental in the accurate assignment of secondary structure. In addition, the tertiary structure was highly constrained by six cysteines separated by many residues that formed three disulfide bridges. Although the correct structure was a member of a short list of plausible structures, the "best" structure was the topological enantiomer of the experimentally determined conformation. For many proteases, other experimentally derived structures can be used as templates to identify the secondary structure elements. In a procedure called modeling by homology, the structure of a known protein is used as a scaffold to predict the structure of another related protein. This method has been used to model a serine and a cysteine protease that are important in the schistosome and malarial life cycles, respectively. The model structures were then used to identify putative small molecule enzyme inhibitors computationally. Experiments confirm that some of these nonpeptidic compounds are active at concentrations of less than 10 microM.

  1. Model Tests on the Retaining Walls Constructed from Geobags Filled with Construction Waste

    Directory of Open Access Journals (Sweden)

    Hua Wen

    2016-01-01

    Full Text Available Geobag retaining wall using construction waste is a new flexible supporting structure, and the usage of construction waste to fill geobags can facilitate the construction recycling. In this paper, model tests were performed on geobag retaining wall using construction waste. The investigation was concentrated on the slope top settlement, the distribution characteristics of the earth pressures on retaining walls and horizontal wall displacements, and slope failure modes. The results indicated that the ultimate loads that the slope tops with retaining walls could bear were 87.5%~125% higher than that of the slope top without retaining walls. The ultimate loading of strengthened slopes with different slope ratios from 1 : 0.75 to 1 : 0.25 could be reduced by 11.8% to 29.4%. The horizontal displacements of the retaining walls constructed from geobags were distributed in a drum shape, with the greatest horizontal displacements occurring about 1/3~1/2 of the wall height away from the bottom of the wall. As the slope ratio increased, the failure of the slope soil supported by geobag retaining wall using construction waste changed from sliding to sliding-toppling (dominated by sliding and then to toppling-sliding (dominated by toppling. The range of 1/3~1/2 of wall height is the weak part of the retaining walls, which should be strengthened with certain measures during the process of design and construction.

  2. A Production Model for Construction: A Theoretical Framework

    Directory of Open Access Journals (Sweden)

    Ricardo Antunes

    2015-03-01

    Full Text Available The building construction industry faces challenges, such as increasing project complexity and scope requirements, but shorter deadlines. Additionally, economic uncertainty and rising business competition with a subsequent decrease in profit margins for the industry demands the development of new approaches to construction management. However, the building construction sector relies on practices based on intuition and experience, overlooking the dynamics of its production system. Furthermore, researchers maintain that the construction industry has no history of the application of mathematical approaches to model and manage production. Much work has been carried out on how manufacturing practices apply to construction projects, mostly lean principles. Nevertheless, there has been little research to understand the fundamental mechanisms of production in construction. This study develops an in-depth literature review to examine the existing knowledge about production models and their characteristics in order to establish a foundation for dynamic production systems management in construction. As a result, a theoretical framework is proposed, which will be instrumental in the future development of mathematical production models aimed at predicting the performance and behaviour of dynamic project-based systems in construction.

  3. Mathematical model of innovative sustainability “green” construction object

    Directory of Open Access Journals (Sweden)

    Slesarev Michail

    2016-01-01

    Full Text Available The paper addresses the issue of finding sustainability of “green” innovative processes in interaction between construction activities and the environment. The problem of today’s construction science is stated as comprehensive integration and automation of natural and artificial intellects within systems that ensure environmental safety of construction based on innovative sustainability of “green” technologies in the life environment, and “green” innovative products. The suggested solution to the problem should formalize sustainability models and methods for interpretation of optimization mathematical modeling problems respective to problems of environmental-based innovative process management, adapted to construction of “green” objects, “green” construction technologies, “green” innovative materials and structures.

  4. Approach to Organizational Structure Modelling in Construction Companies

    Directory of Open Access Journals (Sweden)

    Ilin Igor V.

    2016-01-01

    Full Text Available Effective management system is one of the key factors of business success nowadays. Construction companies usually have a portfolio of independent projects running at the same time. Thus it is reasonable to take into account project orientation of such kind of business while designing the construction companies’ management system, which main components are business process system and organizational structure. The paper describes the management structure designing approach, based on the project-oriented nature of the construction projects, and propose a model of the organizational structure for the construction company. Application of the proposed approach will enable to assign responsibilities within the organizational structure in construction projects effectively and thus to shorten the time for projects allocation and to provide its smoother running. The practical case of using the approach also provided in the paper.

  5. Mathematical Modeling of the Thermal State of an Isothermal Element with Account of the Radiant Heat Transfer Between Parts of a Spacecraft

    Science.gov (United States)

    Alifanov, O. M.; Paleshkin, A. V.; Terent‧ev, V. V.; Firsyuk, S. O.

    2016-01-01

    A methodological approach to determination of the thermal state at a point on the surface of an isothermal element of a small spacecraft has been developed. A mathematical model of heat transfer between surfaces of intricate geometric configuration has been described. In this model, account was taken of the external field of radiant fluxes and of the differentiated mutual influence of the surfaces. An algorithm for calculation of the distribution of the density of the radiation absorbed by surface elements of the object under study has been proposed. The temperature field on the lateral surface of the spacecraft exposed to sunlight and on its shady side has been calculated. By determining the thermal state of magnetic controls of the orientation system as an example, the authors have assessed the contribution of the radiation coming from the solar-cell panels and from the spacecraft surface.

  6. A conceptual model of psychological contracts in construction projects

    Directory of Open Access Journals (Sweden)

    Yongjian Ke

    2016-09-01

    Full Text Available The strategic importance of relationship style contracting is recognised in the construction industry. Both public and private sector clients are stipulating more integrated and collaborative forms of procurement. Despite relationship and integrated contractual arrangement being available for some time, it is clear that construction firms have been slow to adopt them. Hence it is timely to examine how social exchanges, via unwritten agreement and behaviours, are being nurtured in construction projects. This paper adopted the concept of Psychological Contracts (PC to describe unwritten agreement and behaviours. A conceptual model of the PC is developed and validated using the results from a questionnaire survey administered to construction professionals in Australia. The results uncovered the relationships that existed amongst relational conditions and relational benefits, the PC and the partners’ satisfaction. The results show that all the hypotheses in the conceptual model of the PC are supported, suggesting the PC model is important and may have an effect on project performance and relationship quality among contracting parties. A validated model of the PC in construction was then developed based on the correlations among each component. The managerial implications are that past relationships and relationship characteristics should be taken into account in the selection of procurement partners and the promise of future resources, support and tangible relational outcomes are also vital. It is important for contracting parties to pay attention to unwritten agreements (the PC and behaviours when managing construction projects.

  7. Farmer's Friend Biodigester Model Construction Manual

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-11-15

    The success or failure of any biodigester depends mainly upon the suitability of the design, site for construction and quality of construction works, as well as quality of construction materials and workmanship involved during construction. This booklet provides the extensive information on various methods for selecting the appropriate size and site for construction, as well as construction work steps related to the Farmer's Friend model (2005) of biodigester. First, mason's responsibilities are explained. Second, the report continues with the sizes of available biodigesters and the quantity of feeding required. Then, the components of the biogas plant and instructions as to how to select the appropriate size are described. It continues with construction materials and appliances, and the selection of the construction site. Finally, the plant construction is explained from lay-out work to the construction of compost pits, finishing work and instructions to users. If the concerned mason/plumber strictly follows the instruction as described in this construction manual, the biodigester will function properly with the anticipated efficiency and the owner will get the return of his/her investment. This will encourage his/her relatives and neighbours to install biodigesters. However, if the biodigester functions poorly, nobody will be motivated to install it. Poor quality plants will harm the reputation of biogas technology and will have serious negative effects on promotion and extension activities. The masons should, therefore, be well aware that good quality plants will certainly increase the rate of installation with the demonstration effect that ultimately benefits itself, the farmer, and the country as a whole.

  8. The Solar Energetic Particle Event of 2010 August 14: Connectivity with the Solar Source Inferred from Multiple Spacecraft Observations and Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Lario, D.; Kwon, R.-Y.; Raouafi, N. E. [The Johns Hopkins University, Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Richardson, I. G.; Thompson, B. J.; Rosenvinge, T. T. von; Mays, M. L.; Mäkelä, P. A.; Xie, H.; Thakur, N. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Bain, H. M. [Space Sciences Laboratory, UC Berkeley, 7 Gauss Way, Berkeley, CA 94720-7450 (United States); Zhang, M.; Zhao, L. [Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL (United States); Cane, H. V. [Department of Mathematics and Physics, University of Tasmania, Hobart (Australia); Papaioannou, A. [Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, GR-15 236 Penteli (Greece); Riley, P., E-mail: david.lario@jhuapl.edu [Predictive Science, 9990 Mesa Rim Road, Suite 170, San Diego, CA 92121 (United States)

    2017-03-20

    We analyze one of the first solar energetic particle (SEP) events of solar cycle 24 observed at widely separated spacecraft in order to assess the reliability of models currently used to determine the connectivity between the sources of SEPs at the Sun and spacecraft in the inner heliosphere. This SEP event was observed on 2010 August 14 by near-Earth spacecraft, STEREO-A (∼80° west of Earth) and STEREO-B (∼72° east of Earth). In contrast to near-Earth spacecraft, the footpoints of the nominal magnetic field lines connecting STEREO-A and STEREO-B with the Sun were separated from the region where the parent fast halo coronal mass ejection (CME) originated by ∼88° and ∼47° in longitude, respectively. We discuss the properties of the phenomena associated with this solar eruption. Extreme ultraviolet and white-light images are used to specify the extent of the associated CME-driven coronal shock. We then assess whether the SEPs observed at the three heliospheric locations were accelerated by this shock or whether transport mechanisms in the corona and/or interplanetary space provide an alternative explanation for the arrival of particles at the poorly connected spacecraft. A possible scenario consistent with the observations indicates that the observation of SEPs at STEREO-B and near Earth resulted from particle injection by the CME shock onto the field lines connecting to these spacecraft, whereas SEPs reached STEREO-A mostly via cross-field diffusive transport processes. The successes, limitations, and uncertainties of the methods used to resolve the connection between the acceleration sites of SEPs and the spacecraft are evaluated.

  9. Transformation of Malaysian Construction Industry with Building Information Modelling (BIM

    Directory of Open Access Journals (Sweden)

    Latiffi Aryani Ahmad

    2016-01-01

    Full Text Available Building Information Modelling (BIM is a revolution of technology and a process that transformed the way building is planned, designed, analysed, constructed and managed. The revolution of technology and process could increase the quality of construction projects. The knowledge of BIM has been expanding in many countries including Malaysia. Since its inception, the use of BIM has broadened up widely with different purposes. The aims of this paper is to investigate the BIM implementation and uses in Malaysian construction projects. The methodologies adopted for structuring this paper are by using literature review and semi-structured interview with construction players that have experienced and being involved in projects using BIM. The purpose of literature review is to illustrate on the pervious research on the subject matter. Meanwhile, the purpose of interviews is to explore the involvement of construction players, years of experience in projects using BIM and BIM uses in construction projects. The findings revealed that BIM has been implemented in Malaysia since 2007 by various construction players, which are client, architect, C&S engineer, M&E engineer, QS, contractor, facilities manager and BIM consultant. The findings also revealed that BIM is used for project’ visualisation, improving project design, detecting design clashes, quantity take off and operation and maintenance. Further work will be focused on the current practices of construction players in projects using BIM.

  10. A probabilistic model for US nuclear power construction times

    International Nuclear Information System (INIS)

    Shash, A.A.H.

    1988-01-01

    Construction time for nuclear power plants is an important element in planning for resources to meet future load demands. Analysis of actual versus estimated construction times for past US nuclear power plants indicates that utilities have continuously underestimated their power plants' construction durations. The analysis also indicates that the actual average construction time has been increasing upward, and the actual durations of power plants permitted to construct in the same year varied substantially. This study presents two probabilistic models for nuclear power construction time for use by the nuclear industry as estimating tool. The study also presents a detailed explanation of the factors that are responsible for increasing and varying nuclear power construction times. Observations on 91 complete nuclear units were involved in three interdependent analyses in the process of explanation and derivation of the probabilistic models. The historical data was first utilized in the data envelopment analysis (DEA) for the purpose of obtaining frontier index measures for project management achievement in building nuclear power plants

  11. Constructing Multidatabase Collections Using Extended ODMG Object Model

    Directory of Open Access Journals (Sweden)

    Adrian Skehill Mark Roantree

    1999-11-01

    Full Text Available Collections are an important feature in database systems. They provide us with the ability to group objects of interest together, and then to manipulate them in the required fashion. The OASIS project is focused on the construction a multidatabase prototype which uses the ODMG model and a canonical model. As part of this work we have extended the base model to provide a more powerful collection mechanism, and to permit the construction of a federated collection, a collection of heterogenous objects taken from distributed data sources

  12. Simulation-based modeling of building complexes construction management

    Science.gov (United States)

    Shepelev, Aleksandr; Severova, Galina; Potashova, Irina

    2018-03-01

    The study reported here examines the experience in the development and implementation of business simulation games based on network planning and management of high-rise construction. Appropriate network models of different types and levels of detail have been developed; a simulation model including 51 blocks (11 stages combined in 4 units) is proposed.

  13. A construction of observables for AKSZ sigma models

    OpenAIRE

    Mnev, Pavel

    2012-01-01

    A construction of gauge-invariant observables is suggested for a class of topological field theories, the AKSZ sigma-models. The observables are associated to extensions of the target Q-manifold of the sigma model to a Q-bundle over it with additional Hamiltonian structure in fibers.

  14. Social Perception and Social Reality: A Reflection-Construction Model.

    Science.gov (United States)

    Jussim, Lee

    1991-01-01

    A reflection-construction model of relations between social perception and social reality is presented that explicitly specifies several ways in which social perception may relate to social reality. Evidence supporting this model also supports a weaker version of the social-constructivist view. (SLD)

  15. An Environmentally Oriented Constructive Cost Model In Information ...

    African Journals Online (AJOL)

    A model was designed to assist software developers in Nigeria to estimate software effort, duration and cost as a result of the difficulties in understanding the parameters of the traditional Constructive Cost Model II (COCOMO II) , which was designed for a specif ic environment, using Source Lines of Code (SLOC) . Results ...

  16. Modeling Of Construction Noise For Environmental Impact Assessment

    Directory of Open Access Journals (Sweden)

    Mohamed F. Hamoda

    2008-06-01

    Full Text Available This study measured the noise levels generated at different construction sites in reference to the stage of construction and the equipment used, and examined the methods to predict such noise in order to assess the environmental impact of noise. It included 33 construction sites in Kuwait and used artificial neural networks (ANNs for the prediction of noise. A back-propagation neural network (BPNN model was compared with a general regression neural network (GRNN model. The results obtained indicated that the mean equivalent noise level was 78.7 dBA which exceeds the threshold limit. The GRNN model was superior to the BPNN model in its accuracy of predicting construction noise due to its ability to train quickly on sparse data sets. Over 93% of the predictions were within 5% of the observed values. The mean absolute error between the predicted and observed data was only 2 dBA. The ANN modeling proved to be a useful technique for noise predictions required in the assessment of environmental impact of construction activities.

  17. Virtual Models Linked with Physical Components in Construction

    DEFF Research Database (Denmark)

    Sørensen, Kristian Birch

    The use of virtual models supports a fundamental change in the working practice of the construction industry. It changes the primary information carrier (drawings) from simple manually created depictions of the building under construction to visually realistic digital representations that also...... engineering and business development in an iterative and user needs centred system development process. The analysis of future business perspectives presents an extensive number of new working processes that can assist in solving major challenges in the construction industry. Three of the most promising...... practices and development of new ontologies. Based on the experiences gained in this PhD project, some of the important future challenges are also to show the benefits of using modern information and communication technology to practitioners in the construction industry and to communicate this knowledge...

  18. System dynamic modeling on construction waste management in Shenzhen, China.

    Science.gov (United States)

    Tam, Vivian W Y; Li, Jingru; Cai, Hong

    2014-05-01

    This article examines the complexity of construction waste management in Shenzhen, Mainland China. In-depth analysis of waste generation, transportation, recycling, landfill and illegal dumping of various inherent management phases is explored. A system dynamics modeling using Stella model is developed. Effects of landfill charges and also penalties from illegal dumping are also simulated. The results show that the implementation of comprehensive policy on both landfill charges and illegal dumping can effectively control the illegal dumping behavior, and achieve comprehensive construction waste minimization. This article provides important recommendations for effective policy implementation and explores new perspectives for Shenzhen policy makers.

  19. Spacecraft radiator systems

    Science.gov (United States)

    Anderson, Grant A. (Inventor)

    2012-01-01

    A spacecraft radiator system designed to provide structural support to the spacecraft. Structural support is provided by the geometric "crescent" form of the panels of the spacecraft radiator. This integration of radiator and structural support provides spacecraft with a semi-monocoque design.

  20. Event-based soil loss models for construction sites

    Science.gov (United States)

    Trenouth, William R.; Gharabaghi, Bahram

    2015-05-01

    The elevated rates of soil erosion stemming from land clearing and grading activities during urban development, can result in excessive amounts of eroded sediments entering waterways and causing harm to the biota living therein. However, construction site event-based soil loss simulations - required for reliable design of erosion and sediment controls - are one of the most uncertain types of hydrologic models. This study presents models with improved degree of accuracy to advance the design of erosion and sediment controls for construction sites. The new models are developed using multiple linear regression (MLR) on event-based permutations of the Universal Soil Loss Equation (USLE) and artificial neural networks (ANN). These models were developed using surface runoff monitoring datasets obtained from three sites - Greensborough, Cookstown, and Alcona - in Ontario and datasets mined from the literature for three additional sites - Treynor, Iowa, Coshocton, Ohio and Cordoba, Spain. The predictive MLR and ANN models can serve as both diagnostic and design tools for the effective sizing of erosion and sediment controls on active construction sites, and can be used for dynamic scenario forecasting when considering rapidly changing land use conditions during various phases of construction.

  1. Disturbance observer based model predictive control for accurate atmospheric entry of spacecraft

    Science.gov (United States)

    Wu, Chao; Yang, Jun; Li, Shihua; Li, Qi; Guo, Lei

    2018-05-01

    Facing the complex aerodynamic environment of Mars atmosphere, a composite atmospheric entry trajectory tracking strategy is investigated in this paper. External disturbances, initial states uncertainties and aerodynamic parameters uncertainties are the main problems. The composite strategy is designed to solve these problems and improve the accuracy of Mars atmospheric entry. This strategy includes a model predictive control for optimized trajectory tracking performance, as well as a disturbance observer based feedforward compensation for external disturbances and uncertainties attenuation. 500-run Monte Carlo simulations show that the proposed composite control scheme achieves more precise Mars atmospheric entry (3.8 km parachute deployment point distribution error) than the baseline control scheme (8.4 km) and integral control scheme (5.8 km).

  2. Incentive Model Based on Cooperative Relationship in Sustainable Construction Projects

    Directory of Open Access Journals (Sweden)

    Guangdong Wu

    2017-07-01

    Full Text Available Considering the cooperative relationship between owners and contractors in sustainable construction projects, as well as the synergistic effects created by cooperative behaviors, a cooperative incentive model was developed using game theory. The model was formulated and analyzed under both non-moral hazard and moral hazard situations. Then, a numerical simulation and example were proposed to verify the conclusions derived from the model. The results showed that the synergistic effect increases the input intensity of one party’s resource transfer into the increase of marginal utility of the other party, thus the owner and contractor are willing to enhance their levels of effort. One party’s optimal benefit allocation coefficient is positively affected by its own output efficiency, and negatively affected by the other party’s output efficiency. The effort level and expected benefits of the owner and contractor can be improved by enhancing the cooperative relationship between the two parties, as well as enhancing the net benefits of a sustainable construction project. The synergistic effect cannot lower the negative effect of moral hazard behaviors during the implementation of sustainable construction projects. Conversely, the higher levels of the cooperative relationship, the wider the gaps amongst the optimal values under both non-moral hazard and moral hazard situations for the levels of effort, expected benefits and net project benefits. Since few studies to date have emphasized the effects of cooperative relationship on sustainable construction projects, this study constructed a game-based incentive model to bridge the gaps. This study contributes significant theoretical and practical insights into the management of cooperation amongst stakeholders, and into the enhancement of the overall benefits of sustainable construction projects.

  3. Risk of spacecraft on-orbit obsolescence: Novel framework, stochastic modeling, and implications

    Science.gov (United States)

    Dubos, Gregory F.; Saleh, Joseph H.

    2010-07-01

    The Government Accountability Office (GAO) has repeatedly noted the difficulties encountered by the Department of Defense (DOD) in keeping its acquisition of space systems on schedule and within budget. Among the recommendations provided by GAO, a minimum Technology Readiness Level (TRL) for technologies to be included in the development of a space system is advised. The DOD considers this recommendation impractical arguing that if space systems were designed with only mature technologies (high TRL), they would likely become obsolete on-orbit fairly quickly. The risk of on-orbit obsolescence is a key argument in the DOD's position for dipping into low technology maturity for space acquisition programs, but this policy unfortunately often results in the cost growth and schedule slippage criticized by the GAO. The concept of risk of on-orbit obsolescence has remained qualitative to date. In this paper, we formulate a theory of risk of on-orbit obsolescence by building on the traditional notion of obsolescence and adapting it to the specificities of space systems. We develop a stochastic model for quantifying and analyzing the risk of on-orbit obsolescence, and we assess, in its light, the appropriateness of DOD's rationale for maintaining low TRL technologies in its acquisition of space assets as a strategy for mitigating on-orbit obsolescence. Our model and results contribute one step towards the resolution of the conceptual stalemate on this matter between the DOD and the GAO, and we hope will inspire academics to further investigate the risk of on-orbit obsolescence.

  4. Model construction by students within an integrated medical curriculum.

    Science.gov (United States)

    Barling, Peter M; Ramasamy, Perumal

    2011-03-01

    This paper presents our experience of running a special study module (SSM) in the second semester of the first year of our 5-year medical programme, worth 10 per cent of that semester's assessment, in which each student constructs an individually selected model illustrating a specific aspect of the teaching course. Each student conceptualises and develops his or her model, to clarify a specific aspect of medical teaching. The use of non-traditional materials in construction is strongly encouraged. Six weeks later, each student presents their model for assessment by four first-year academic teaching staff. The student is quizzed about the concepts that he or she presents, the mode of construction and the materials used. The students' projects broadly cover the disciplines of physiology, biochemistry and anatomy, but are somewhat biased towards anatomy. Students spend on average about 14 hours planning and building their models, at a time when they are busy with other teaching activities. The marks awarded for the projects closely follow a normal distribution. A survey suggests that most students enjoy the exercise and feel that it has enhanced their learning and understanding. It is clear from the wide variety of different topics, models and materials that students are highly resourceful in their modelling. Creative activity does not generally play a substantial part in medical education, but is of considerable importance. The development of their models stimulates, informs and educates the constructors, and provides a teaching resource for later use in didactic teaching. © Blackwell Publishing Ltd 2011.

  5. The role of business models in Finnish construction companies

    Directory of Open Access Journals (Sweden)

    Aki Pekuri

    2013-09-01

    Full Text Available Business models are seen as an essential part of successful businesses as they define the way companies create value for their customers and subsequently make profit from their operations. A good business model has a potential to separate a company from its competitors by creating a competitive advantage. The purpose of this research is to explore how managers understand and deploy the business model concept in construction. For this, eight experienced managers have been interviewed and their answers have been analysed using the theoretical aspects of business models as a reference. In the interviews, managers deployed business model concept very differently than what is accustomed in practice and in academia; they relate these models to different project delivery and contract structures or to companies’ business segments rather than to analysing how their companies provide value for customers in the selected markets. The results of the interviews indicate that the managers in construction do neither understand the concept properly nor exploit any similar value creation analysis in their business. The interviewees had significant problems describing their companies’ business models and value creation logic, pointing out the lack of analysis and understanding of customer values and needs in the project delivery process. This may be one of the overtones of the persistent client dissatisfaction in the construction industry. 

  6. The role of business models in Finnish construction companies

    Directory of Open Access Journals (Sweden)

    Aki Pekuri

    2013-09-01

    Full Text Available Business models are seen as an essential part of successful businesses as they define the way companies create value for their customers and subsequently make profit from their operations. A good business model has a potential to separate a company from its competitors by creating a competitive advantage. The purpose of this research is to explore how managers understand and deploy the business model concept in construction. For this, eight experienced managers have been interviewed and their answers have been analysed using the theoretical aspects of business models as a reference. In the interviews, managers deployed business model concept very differently than what is accustomed in practice and in academia; they relate these models to different project delivery and contract structures or to companies’ business segments rather than to analysing how their companies provide value for customers in the selected markets. The results of the interviews indicate that the managers in construction do neither understand the concept properly nor exploit any similar value creation analysis in their business. The interviewees had significant problems describing their companies’ business models and value creation logic, pointing out the lack of analysis and understanding of customer values and needs in the project delivery process. This may be one of the overtones of the persistent client dissatisfaction in the construction industry.

  7. Peculiarities of constructing the models of mass religious communication

    Directory of Open Access Journals (Sweden)

    Petrushkevych Maria Stefanivna

    2017-07-01

    Full Text Available Religious communication is a full-fledged, effective part of the mass information field. It uses new media to fulfil its needs. And it also functions in the field of mass culture and the information society. To describe the features of mass religious communication in the article, the author constructs a graphic model of its functioning.

  8. Seeking a Multi-Construct Model of Morality

    Science.gov (United States)

    McDaniel, Brenda L.; Grice, James W.; Eason, E. Allen

    2010-01-01

    The present study explored a multi-construct model of moral development. Variables commonly seen in the moral development literature, such as family interactions, spiritual life, ascription to various sources of moral authority, empathy, shame, guilt and moral judgement competence, were investigated. Results from the current study support previous…

  9. Queering Constructs: Proposing a Dynamic Gender and Sexuality Model

    Science.gov (United States)

    Jourian, T. J.

    2015-01-01

    Higher education educators commonly understand social identities, including gender, to be fluid and dynamic. Lev's (2004) model of four components of sexual identity is commonly used to demonstrate the fluidity of sex, gender, and sexuality for individuals, but it does little to address the fixedness of those constructs. Through a multipronged…

  10. A Constructive Neural-Network Approach to Modeling Psychological Development

    Science.gov (United States)

    Shultz, Thomas R.

    2012-01-01

    This article reviews a particular computational modeling approach to the study of psychological development--that of constructive neural networks. This approach is applied to a variety of developmental domains and issues, including Piagetian tasks, shift learning, language acquisition, number comparison, habituation of visual attention, concept…

  11. An Intervention Model of Constructive Conflict Resolution and Cooperative Learning.

    Science.gov (United States)

    Zhang, Quanwu

    1994-01-01

    Tests an intervention model of constructive conflict resolution (CCR) and cooperative learning in three urban high schools. Findings show that improvements in CCR increased social support and decreased victimization for the students. These changes improved student's attitudes, self-esteem, interpersonal relations, and academic achievement. (GLR)

  12. Narrative Construction, Social Perceptions, and the Situation Model.

    Science.gov (United States)

    Costabile, Kristi A

    2016-05-01

    The present investigation examined how three salient features of narrative thinking (situation model construction, linguistic concreteness, and perspective-taking) influenced the social inference process. Results of four experiments indicated that compared with those given other objectives, perceivers given narrative objectives were: (a) more likely to make situation rather than trait attributions for observed behaviors (Experiment 1), (b) less likely to make implicit trait inferences (Experiment 2), and (c) less likely to rely on behavior valence when making evaluative judgments (Experiment 4). Linguistic analyses indicated that narrative construction consistently entailed the creation of situation models of events and linguistic concreteness, but only situation model creation mediated the relationship between narrative and inferences. Experiment 3 confirmed the mediating role of situation models: Perceivers with narrative objectives made trait inferences only when behaviors were inconsistent with contextual information. The role of these core narrative features on social perceptions is discussed. © 2016 by the Society for Personality and Social Psychology, Inc.

  13. Financial and organizational models of NPP construction projects

    International Nuclear Information System (INIS)

    Ivanov, Timur

    2010-01-01

    The recent evolution of financial and organizational models of NPP projects can be truly reputed to open a new page of the world market of NPP construction. The definition of the concrete model is based mostly on specific cooperation backgrounds and current terms and conditions under which the particular NPP project is being evolved. In this article the most commonly known strategies and schemes of financing structuring for export NPP construction projects are scrutinized. Special attention is paid to the analysis of BOO/BOT models which are based on the public-private partnership. Most BOO/BOT projects in the power sector has Power Purchase Agreements (PPA) as an integral part of them. The PPA key principles are studied here as well. The flexibility and adaptability of the public-private partnership models for financing and organization of the NPP projects contributes substantially to the competitiveness of the NPP projects especially under current economic conditions. (orig.)

  14. Spacecraft Jitter Attenuation Using Embedded Piezoelectric Actuators

    Science.gov (United States)

    Belvin, W. Keith

    1995-01-01

    Remote sensing from spacecraft requires precise pointing of measurement devices in order to achieve adequate spatial resolution. Unfortunately, various spacecraft disturbances induce vibrational jitter in the remote sensing instruments. The NASA Langley Research Center has performed analysis, simulations, and ground tests to identify the more promising technologies for minimizing spacecraft pointing jitter. These studies have shown that the use of smart materials to reduce spacecraft jitter is an excellent match between a maturing technology and an operational need. This paper describes the use of embedding piezoelectric actuators for vibration control and payload isolation. In addition, recent advances in modeling, simulation, and testing of spacecraft pointing jitter are discussed.

  15. Modeling Financial Liquidity Of Construction Companies Using Error Correction Mechanism

    Directory of Open Access Journals (Sweden)

    Tomasz Stryjewski

    2017-03-01

    Full Text Available Financial liquidity is one of the most important economic categories in the functioning of the company. There are many methods of assessment of the company in this field, ranging from ratio analysis, to advanced models of financial flows. In this paper was presented econometric model of financial income, which was used to analyze the liquidity of the three construction companies. This analysis was made on the background of methods indicator.

  16. Phenomenological Hints from a Class of String Motivated Model Constructions

    Directory of Open Access Journals (Sweden)

    Hans Peter Nilles

    2015-01-01

    Full Text Available We use string theory constructions towards the generalisation of the supersymmetric standard model of strong and electroweak interactions. Properties of the models depend crucially on the location of fields in extradimensional compact space. This allows us to extract some generic lessons for the phenomenological properties of the low energy effective action. Within this scheme we present a compelling model based on local grand unification and mirage mediation of supersymmetry breakdown. We analyse the properties of the specific model towards its possible tests at the LHC and the complementarity to direct dark matter searches.

  17. Construction of a novel economy-climate model

    Institute of Scientific and Technical Information of China (English)

    CHOU JieMing; DONG WenJie; YE DuZheng

    2007-01-01

    An attempt has been made to construct a novel economy-climate model by combining climate change research with agricultural economy research to evaluate the influence of global climate change on grain yields. The insertion of a climate change factor into the economic C-D (Cobb-Dauglas) production function model yields a novel evaluation model, which connects the climate change factor to the economic variation factor, and the performance and reasonableness of the novel evaluation model are also preliminarily simulated and verified.

  18. CFD modelling of moisture interactions between air and constructions

    DEFF Research Database (Denmark)

    Mortensen, Lone Hedegaard; Woloszyn, Monika; Hohota, Raluca

    2005-01-01

    There is a strong demand for accurate moisture modelling since moisture poses a risk for both the constructions and the indoor climate. Thus, in this investigation there is special focus on moisture modelling. The paper describes a new model based on a CFD tool that is enhanced to include both...... detailed modelling of airflows in rooms and heat and moisture transfer in walls by applying them as fluid walls. In a 3D configuration the impact of different boundary conditions are investigated and the results are discussed. The changes of boundary conditions that are studied are velocity, moisture...

  19. Artist concept of Galileo spacecraft

    Science.gov (United States)

    1988-01-01

    Galileo spacecraft is illustrated in artist concept. Gallileo, named for the Italian astronomer, physicist and mathematician who is credited with construction of the first complete, practical telescope in 1620, will make detailed studies of Jupiter. A cooperative program with the Federal Republic of Germany the Galileo mission will amplify information acquired by two Voyager spacecraft in their brief flybys. Galileo is a two-element system that includes a Jupiter-orbiting observatory and an entry probe. Jet Propulsion Laboratory (JPL) is Galileo project manager and builder of the main spacecraft. Ames Research Center (ARC) has responsibility for the entry probe, which was built by Hughes Aircraft Company and General Electric. Galileo will be deployed from the payload bay (PLB) of Atlantis, Orbiter Vehicle (OV) 104, during mission STS-34.

  20. Causality in Psychiatry: A Hybrid Symptom Network Construct Model

    Directory of Open Access Journals (Sweden)

    Gerald eYoung

    2015-11-01

    Full Text Available Causality or etiology in psychiatry is marked by standard biomedical, reductionistic models (symptoms reflect the construct involved that inform approaches to nosology, or classification, such as in the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition; American Psychiatric Association, 2013. However, network approaches to symptom interaction (i.e., symptoms are formative of the construct; e.g., McNally, Robinaugh, Wu, Wang, Deserno, & Borsboom, 2014, for PTSD (posttraumatic stress disorder are being developed that speak to bottom-up processes in mental disorder, in contrast to the typical top-down psychological construct approach. The present article presents a hybrid top-down, bottom-up model of the relationship between symptoms and mental disorder, viewing symptom expression and their causal complex as a reciprocally dynamic system with multiple levels, from lower-order symptoms in interaction to higher-order constructs affecting them. The hybrid model hinges on good understanding of systems theory in which it is embedded, so that the article reviews in depth nonlinear dynamical systems theory (NLDST. The article applies the concept of emergent circular causality (Young, 2011 to symptom development, as well. Conclusions consider that symptoms vary over several dimensions, including: subjectivity; objectivity; conscious motivation effort; and unconscious influences, and the degree to which individual (e.g., meaning and universal (e.g., causal processes are involved. The opposition between science and skepticism is a complex one that the article addresses in final comments.

  1. Intelligent spacecraft module

    Science.gov (United States)

    Oungrinis, Konstantinos-Alketas; Liapi, Marianthi; Kelesidi, Anna; Gargalis, Leonidas; Telo, Marinela; Ntzoufras, Sotiris; Paschidi, Mariana

    2014-12-01

    The paper presents the development of an on-going research project that focuses on a human-centered design approach to habitable spacecraft modules. It focuses on the technical requirements and proposes approaches on how to achieve a spatial arrangement of the interior that addresses sufficiently the functional, physiological and psychosocial needs of the people living and working in such confined spaces that entail long-term environmental threats to human health and performance. Since the research perspective examines the issue from a qualitative point of view, it is based on establishing specific relationships between the built environment and its users, targeting people's bodily and psychological comfort as a measure toward a successful mission. This research has two basic branches, one examining the context of the system's operation and behavior and the other in the direction of identifying, experimenting and formulating the environment that successfully performs according to the desired context. The latter aspect is researched upon the construction of a scaled-model on which we run series of tests to identify the materiality, the geometry and the electronic infrastructure required. Guided by the principles of sensponsive architecture, the ISM research project explores the application of the necessary spatial arrangement and behavior for a user-centered, functional interior where the appropriate intelligent systems are based upon the existing mechanical and chemical support ones featured on space today, and especially on the ISS. The problem is set according to the characteristics presented at the Mars500 project, regarding the living quarters of six crew-members, along with their hygiene, leisure and eating areas. Transformable design techniques introduce spatial economy, adjustable zoning and increased efficiency within the interior, securing at the same time precise spatial orientation and character at any given time. The sensponsive configuration is

  2. Modelling in Primary School: Constructing Conceptual Models and Making Sense of Fractions

    Science.gov (United States)

    Shahbari, Juhaina Awawdeh; Peled, Irit

    2017-01-01

    This article describes sixth-grade students' engagement in two model-eliciting activities offering students the opportunity to construct mathematical models. The findings show that students utilized their knowledge of fractions including conceptual and procedural knowledge in constructing mathematical models for the given situations. Some students…

  3. Building Information Modeling for Managing Design and Construction

    DEFF Research Database (Denmark)

    Berard, Ole Bengt

    outcome of construction work. Even though contractors regularly encounter design information problems, these issues are accepted as a condition of doing business and better design information has yet to be defined. Building information modeling has the inherent promise of improving the quality of design...... information for work tasks. * Amount of Information – the number of documents and files, and other media, should be appropriate for the scope. The criteria were identified by empirical studies and theory on information quality in the architectural, engineering and construction (AEC) industry and other fields......Contractors planning and executing construction work encounter many kinds of problems with design information, such as uncoordinated drawings and specification, missing relevant information, and late delivery of design information. Research has shown that missing design information and unintended...

  4. A Spanish model for quantification and management of construction waste

    International Nuclear Information System (INIS)

    Solis-Guzman, Jaime; Marrero, Madelyn; Montes-Delgado, Maria Victoria; Ramirez-de-Arellano, Antonio

    2009-01-01

    Currently, construction and demolition waste (C and D waste) is a worldwide issue that concerns not only governments but also the building actors involved in construction activity. In Spain, a new national decree has been regulating the production and management of C and D waste since February 2008. The present work describes the waste management model that has inspired this decree: the Alcores model implemented with good results in Los Alcores Community (Seville, Spain). A detailed model is also provided to estimate the volume of waste that is expected to be generated on the building site. The quantification of C and D waste volume, from the project stage, is essential for the building actors to properly plan and control its disposal. This quantification model has been developed by studying 100 dwelling projects, especially their bill of quantities, and defining three coefficients to estimate the demolished volume (CT), the wreckage volume (CR) and the packaging volume (CE). Finally, two case studies are included to illustrate the usefulness of the model to estimate C and D waste volume in both new construction and demolition projects.

  5. A Spanish model for quantification and management of construction waste.

    Science.gov (United States)

    Solís-Guzmán, Jaime; Marrero, Madelyn; Montes-Delgado, Maria Victoria; Ramírez-de-Arellano, Antonio

    2009-09-01

    Currently, construction and demolition waste (C&D waste) is a worldwide issue that concerns not only governments but also the building actors involved in construction activity. In Spain, a new national decree has been regulating the production and management of C&D waste since February 2008. The present work describes the waste management model that has inspired this decree: the Alcores model implemented with good results in Los Alcores Community (Seville, Spain). A detailed model is also provided to estimate the volume of waste that is expected to be generated on the building site. The quantification of C&D waste volume, from the project stage, is essential for the building actors to properly plan and control its disposal. This quantification model has been developed by studying 100 dwelling projects, especially their bill of quantities, and defining three coefficients to estimate the demolished volume (CT), the wreckage volume (CR) and the packaging volume (CE). Finally, two case studies are included to illustrate the usefulness of the model to estimate C&D waste volume in both new construction and demolition projects.

  6. Modeling system for the rapid construction in Syria

    Directory of Open Access Journals (Sweden)

    Ahmed, Sonia

    2016-06-01

    Full Text Available Prefabrication is a manufacturing process conducted at a specialized facility, in which various materials are joined to form a component part of the final installation. Prefabrication techniques have been progressively adopted in the construction industry in various countries. The demand was at its peak in the early 1970s in Eastern and Western Europe for the construction of new towns. Worldwide, the highest precast levels in 1996 were located in Denmark (43%, the Netherlands (40%, Sweden and Germany (31%. In Asia, the precast levels in Japan and Singapore were about 15% and 8%, respectively, recently, the use of prefabrication is further encouraged to increase productivity and build ability. In Syria too, the first residential project in Damascus: the establishment of 2400 housing units in the year (77-80. Except that the rate of construction pre-cast in Syria is still not exceed 2% of Building of reinforced concrete. In order to participate in the reconstruction of Syria, after the destruction and devastation caused by the war over four years, this search evaluates successful international experiences in rapid construction technique, and modeled system that could serve the current Syrian reality. Introduction of this technology as a new method in the world of construction in Syria requires a good base, relying on the availability of the necessary raw materials and nearness of work site, as well as the need to replace old technology into modern technology, and analyzing the economic, social, environmental criteria, to make the decision about the best solution. Cost and time will form the most important indicators that will be analyzed and calculated, before the final model mode, in order to be able to use this system later in Syrian construction companies.

  7. A probabilistic graphical model based stochastic input model construction

    International Nuclear Information System (INIS)

    Wan, Jiang; Zabaras, Nicholas

    2014-01-01

    Model reduction techniques have been widely used in modeling of high-dimensional stochastic input in uncertainty quantification tasks. However, the probabilistic modeling of random variables projected into reduced-order spaces presents a number of computational challenges. Due to the curse of dimensionality, the underlying dependence relationships between these random variables are difficult to capture. In this work, a probabilistic graphical model based approach is employed to learn the dependence by running a number of conditional independence tests using observation data. Thus a probabilistic model of the joint PDF is obtained and the PDF is factorized into a set of conditional distributions based on the dependence structure of the variables. The estimation of the joint PDF from data is then transformed to estimating conditional distributions under reduced dimensions. To improve the computational efficiency, a polynomial chaos expansion is further applied to represent the random field in terms of a set of standard random variables. This technique is combined with both linear and nonlinear model reduction methods. Numerical examples are presented to demonstrate the accuracy and efficiency of the probabilistic graphical model based stochastic input models. - Highlights: • Data-driven stochastic input models without the assumption of independence of the reduced random variables. • The problem is transformed to a Bayesian network structure learning problem. • Examples are given in flows in random media

  8. Computer simulation of spacecraft/environment interaction

    International Nuclear Information System (INIS)

    Krupnikov, K.K.; Makletsov, A.A.; Mileev, V.N.; Novikov, L.S.; Sinolits, V.V.

    1999-01-01

    This report presents some examples of a computer simulation of spacecraft interaction with space environment. We analysed a set data on electron and ion fluxes measured in 1991-1994 on geostationary satellite GORIZONT-35. The influence of spacecraft eclipse and device eclipse by solar-cell panel on spacecraft charging was investigated. A simple method was developed for an estimation of spacecraft potentials in LEO. Effects of various particle flux impact and spacecraft orientation are discussed. A computer engineering model for a calculation of space radiation is presented. This model is used as a client/server model with WWW interface, including spacecraft model description and results representation based on the virtual reality markup language

  9. Computer simulation of spacecraft/environment interaction

    CERN Document Server

    Krupnikov, K K; Mileev, V N; Novikov, L S; Sinolits, V V

    1999-01-01

    This report presents some examples of a computer simulation of spacecraft interaction with space environment. We analysed a set data on electron and ion fluxes measured in 1991-1994 on geostationary satellite GORIZONT-35. The influence of spacecraft eclipse and device eclipse by solar-cell panel on spacecraft charging was investigated. A simple method was developed for an estimation of spacecraft potentials in LEO. Effects of various particle flux impact and spacecraft orientation are discussed. A computer engineering model for a calculation of space radiation is presented. This model is used as a client/server model with WWW interface, including spacecraft model description and results representation based on the virtual reality markup language.

  10. A Systematic Approach to Modelling Change Processes in Construction Projects

    Directory of Open Access Journals (Sweden)

    Ibrahim Motawa

    2012-11-01

    Full Text Available Modelling change processes within construction projects isessential to implement changes efficiently. Incomplete informationon the project variables at the early stages of projects leads toinadequate knowledge of future states and imprecision arisingfrom ambiguity in project parameters. This lack of knowledge isconsidered among the main source of changes in construction.Change identification and evaluation, in addition to predictingits impacts on project parameters, can help in minimising thedisruptive effects of changes. This paper presents a systematicapproach to modelling change process within construction projectsthat helps improve change identification and evaluation. Theapproach represents the key decisions required to implementchanges. The requirements of an effective change processare presented first. The variables defined for efficient changeassessment and diagnosis are then presented. Assessmentof construction changes requires an analysis for the projectcharacteristics that lead to change and also analysis of therelationship between the change causes and effects. The paperconcludes that, at the early stages of a project, projects with a highlikelihood of change occurrence should have a control mechanismover the project characteristics that have high influence on theproject. It also concludes, for the relationship between changecauses and effects, the multiple causes of change should bemodelled in a way to enable evaluating the change effects moreaccurately. The proposed approach is the framework for tacklingsuch conclusions and can be used for evaluating change casesdepending on the available information at the early stages ofconstruction projects.

  11. A Model Suggestion to Predict Leverage Ratio for Construction Projects

    Directory of Open Access Journals (Sweden)

    Özlem Tüz

    2013-12-01

    Full Text Available Due to the nature, construction is an industry with high uncertainty and risk. Construction industry carries high leverage ratios. Firms with low equities work in big projects through progress payment system, but in this case, even a small negative in the planned cash flows constitute a major risk for the company.The use of leverage, with a small investment to achieve profit targets large-scale, high-profit, but also brings a high risk with it. Investors may lose all or the portion of the money. In this study, monitoring and measuring of the leverage ratio because of the displacement in cash inflows of construction projects which uses high leverage and low cash to do business in the sector is targeted. Cash need because of drifting the cash inflows may be seen due to the model. Work should be done in the early stages of the project with little capital but in the later stages, rapidly growing capital need arises.The values obtained from the model may be used to supply the capital held in the right time by anticipating the risks because of the delay in cashflow of construction projects which uses high leverage ratio.

  12. Toward autonomous spacecraft

    Science.gov (United States)

    Fogel, L. J.; Calabrese, P. G.; Walsh, M. J.; Owens, A. J.

    1982-01-01

    Ways in which autonomous behavior of spacecraft can be extended to treat situations wherein a closed loop control by a human may not be appropriate or even possible are explored. Predictive models that minimize mean least squared error and arbitrary cost functions are discussed. A methodology for extracting cyclic components for an arbitrary environment with respect to usual and arbitrary criteria is developed. An approach to prediction and control based on evolutionary programming is outlined. A computer program capable of predicting time series is presented. A design of a control system for a robotic dense with partially unknown physical properties is presented.

  13. Modelling, Construction, and Testing of a Simple HTS Machine Demonstrator

    DEFF Research Database (Denmark)

    Jensen, Bogi Bech; Abrahamsen, Asger Bech

    2011-01-01

    This paper describes the construction, modeling and experimental testing of a high temperature superconducting (HTS) machine prototype employing second generation (2G) coated conductors in the field winding. The prototype is constructed in a simple way, with the purpose of having an inexpensive way...... of validating finite element (FE) simulations and gaining a better understanding of HTS machines. 3D FE simulations of the machine are compared to measured current vs. voltage (IV) curves for the tape on its own. It is validated that this method can be used to predict the critical current of the HTS tape...... installed in the machine. The measured torque as a function of rotor position is also reproduced by the 3D FE model....

  14. Constructing topic models of Internet of Things for information processing.

    Science.gov (United States)

    Xin, Jie; Cui, Zhiming; Zhang, Shukui; He, Tianxu; Li, Chunhua; Huang, Haojing

    2014-01-01

    Internet of Things (IoT) is regarded as a remarkable development of the modern information technology. There is abundant digital products data on the IoT, linking with multiple types of objects/entities. Those associated entities carry rich information and usually in the form of query records. Therefore, constructing high quality topic hierarchies that can capture the term distribution of each product record enables us to better understand users' search intent and benefits tasks such as taxonomy construction, recommendation systems, and other communications solutions for the future IoT. In this paper, we propose a novel record entity topic model (RETM) for IoT environment that is associated with a set of entities and records and a Gibbs sampling-based algorithm is proposed to learn the model. We conduct extensive experiments on real-world datasets and compare our approach with existing methods to demonstrate the advantage of our approach.

  15. Canopy Modeling of Aquatic Vegetation: Construction of Submerged Vegetation Index

    Science.gov (United States)

    Ma, Z.; Zhou, G.

    2018-04-01

    The unique spectral characteristics of submerged vegetation in wetlands determine that the conventional terrestrial vegetation index cannot be directly employed to species identification and parameter inversion of submerged vegetation. Based on the Aquatic Vegetation Radiative Transfer model (AVRT), this paper attempts to construct an index suitable for submerged vegetation, the model simulated data and a scene of Sentinel-2A image in Taihu Lake, China are utilized for assessing the performance of the newly constructed indices and the existent vegetation indices. The results show that the angle index composed by 525 nm, 555 nm and 670 nm can resist the effects of water columns and is more sensitive to vegetation parameters such as LAI. Furthermore, it makes a well discrimination between submerged vegetation and water bodies in the satellite data. We hope that the new index will provide a theoretical basis for future research.

  16. Constructing Topic Models of Internet of Things for Information Processing

    Science.gov (United States)

    Xin, Jie; Cui, Zhiming; Zhang, Shukui; He, Tianxu; Li, Chunhua; Huang, Haojing

    2014-01-01

    Internet of Things (IoT) is regarded as a remarkable development of the modern information technology. There is abundant digital products data on the IoT, linking with multiple types of objects/entities. Those associated entities carry rich information and usually in the form of query records. Therefore, constructing high quality topic hierarchies that can capture the term distribution of each product record enables us to better understand users' search intent and benefits tasks such as taxonomy construction, recommendation systems, and other communications solutions for the future IoT. In this paper, we propose a novel record entity topic model (RETM) for IoT environment that is associated with a set of entities and records and a Gibbs sampling-based algorithm is proposed to learn the model. We conduct extensive experiments on real-world datasets and compare our approach with existing methods to demonstrate the advantage of our approach. PMID:25110737

  17. Adaptive Estimation and Heuristic Optimization of Nonlinear Spacecraft Attitude Dynamics

    Science.gov (United States)

    2016-09-15

    Biology, Control and Artificial Intelligence , MIT Press, Cambridge, MA, USA, 1992. 177 [89] Thompson, R. E., Colombi, J. M., Black, J. T., and Ayres...utilized for parameter and state estimates. MMAE algorithms involve constructing a bank of recursive estimators, each assuming a different hypothesis for...this research, MMAE routines employing parallel banks of unscented attitude filters are applied to analytical models of spacecraft with time- varying

  18. MEGACELL: A nanocrystal model construction software for HRTEM multislice simulation

    International Nuclear Information System (INIS)

    Stroppa, Daniel G.; Righetto, Ricardo D.; Montoro, Luciano A.; Ramirez, Antonio J.

    2011-01-01

    Image simulation has an invaluable importance for the accurate analysis of High Resolution Transmission Electron Microscope (HRTEM) results, especially due to its non-linear image formation mechanism. Because the as-obtained images cannot be interpreted in a straightforward fashion, the retrieval of both qualitative and quantitative information from HRTEM micrographs requires an iterative process including the simulation of a nanocrystal model and its comparison with experimental images. However most of the available image simulation software requires atom-by-atom coordinates as input for the calculations, which can be prohibitive for large finite crystals and/or low-symmetry systems and zone axis orientations. This paper presents an open source citation-ware tool named MEGACELL, which was developed to assist on the construction of nanocrystals models. It allows the user to build nanocrystals with virtually any convex polyhedral geometry and to retrieve its atomic positions either as a plain text file or as an output compatible with EMS (Electron Microscopy Software) input protocol. In addition to the description of this tool features, some construction examples and its application for scientific studies are presented. These studies show MEGACELL as a handy tool, which allows an easier construction of complex nanocrystal models and improves the quantitative information extraction from HRTEM images. -- Highlights: → A software to support the HRTEM image simulation of nanocrystals in actual size. → MEGACELL allows the construction of complex nanocrystals models for multislice image simulation. → Some examples of improved nanocrystalline system characterization are presented, including the analysis of 3D morphology and growth behavior.

  19. Constructing unified models based on E8 in ten dimensions

    International Nuclear Information System (INIS)

    Kapetanakis, D.

    1992-01-01

    We examine the virtues and difficulties of the attempts to construct realistic four-dimensional models from a gauge theory based on E 8 and defined in ten dimensions. The four-dimensional theories are obtained using the coset space dimensional reduction scheme. Some of our points and in particular the proposed mechanism for supersymmetry breaking might be useful in other dimensional reduction schemes. (orig.)

  20. Model construction of nursing service satisfaction in hospitalized tumor patients.

    Science.gov (United States)

    Chen, Yongyi; Liu, Jingshi; Xiao, Shuiyuan; Liu, Xiangyu; Tang, Xinhui; Zhou, Yujuan

    2014-01-01

    This study aims to construct a satisfaction model on nursing service in hospitalized tumor patients. Using questionnaires, data about hospitalized tumor patients' expectation, quality perception and satisfaction of hospital nursing service were obtained. A satisfaction model of nursing service in hospitalized tumor patients was established through empirical study and by structural equation method. This model was suitable for tumor specialized hospital, with reliability and validity. Patient satisfaction was significantly affected by quality perception and patient expectation. Patient satisfaction and patient loyalty was also affected by disease pressure. Hospital brand was positively correlated with patient satisfaction and patient loyalty, negatively correlated with patient complaint. Patient satisfaction was positively correlated with patient loyalty, patient complaints, and quality perception, and negatively correlated with disease pressure and patient expectation. The satisfaction model on nursing service in hospitalized tumor patients fits well. By this model, the quality of hospital nursing care may be improved.

  1. Simplified hydraulic model of French vertical-flow constructed wetlands.

    Science.gov (United States)

    Arias, Luis; Bertrand-Krajewski, Jean-Luc; Molle, Pascal

    2014-01-01

    Designing vertical-flow constructed wetlands (VFCWs) to treat both rain events and dry weather flow is a complex task due to the stochastic nature of rain events. Dynamic models can help to improve design, but they usually prove difficult to handle for designers. This study focuses on the development of a simplified hydraulic model of French VFCWs using an empirical infiltration coefficient--infiltration capacity parameter (ICP). The model was fitted using 60-second-step data collected on two experimental French VFCW systems and compared with Hydrus 1D software. The model revealed a season-by-season evolution of the ICP that could be explained by the mechanical role of reeds. This simplified model makes it possible to define time-course shifts in ponding time and outlet flows. As ponding time hinders oxygen renewal, thus impacting nitrification and organic matter degradation, ponding time limits can be used to fix a reliable design when treating both dry and rain events.

  2. Potential and Benefits of Building Information Modeling (BIM) During Pre-Construction, Construction and Post Construction Stage

    OpenAIRE

    Aw Nien Wei; Md Azree Othuman Mydin

    2017-01-01

    The construction industry is the main economic support for all countries around the world in which continually adapting to meet competitive challenges around the global market. Nevertheless, the construction project is becoming much more complex and difficult to manage. This is because the construction project involves a large number of stakeholder, for example, the consultant companies, architects, engineers, building surveyors and quantity surveyors. The technology current...

  3. Implementation of building information modeling in Malaysian construction industry

    Science.gov (United States)

    Memon, Aftab Hameed; Rahman, Ismail Abdul; Harman, Nur Melly Edora

    2014-10-01

    This study has assessed the implementation level of Building Information Modeling (BIM) in the construction industry of Malaysia. It also investigated several computer software packages facilitating BIM and challenges affecting its implementation. Data collection for this study was carried out using questionnaire survey among the construction practitioners. 95 completed forms of questionnaire received against 150 distributed questionnaire sets from consultant, contractor and client organizations were analyzed statistically. Analysis findings indicated that the level of implementation of BIM in the construction industry of Malaysia is very low. Average index method employed to assess the effectiveness of various software packages of BIM highlighted that Bentley construction, AutoCAD and ArchiCAD are three most popular and effective software packages. Major challenges to BIM implementation are it requires enhanced collaboration, add work to a designer, interoperability and needs enhanced collaboration. For improving the level of implementing BIM in Malaysian industry, it is recommended that a flexible training program of BIM for all practitioners must be created.

  4. Spacecraft performance Analysis For Extreme events by integration and Combination Of Sensing, Modelling and OptimiSation

    DEFF Research Database (Denmark)

    Cowlard, A.; Jomaas, Grunde; Torero, J. L.

    2011-01-01

    To supersede the current state-of-the-art of fire safety in spacecrafts, ESA has commissioned a topical team to define an unprecedented series of demonstration and validation experiments. This initiative aims to move fire safety away from test standards and into a truly scientific selection of bo...

  5. The Solution Construction of Heterotic Super-Liouville Model

    Science.gov (United States)

    Yang, Zhan-Ying; Zhen, Yi

    2001-12-01

    We investigate the heterotic super-Liouville model on the base of the basic Lie super-algebra Osp(1|2).Using the super extension of Leznov-Saveliev analysis and Drinfeld-Sokolov linear system, we construct the explicit solution of the heterotic super-Liouville system in component form. We also show that the solutions are local and periodic by calculating the exchange relation of the solution. Finally starting from the action of heterotic super-Liouville model, we obtain the conserved current and conserved charge which possessed the BRST properties.

  6. Algorithmic fault tree construction by component-based system modeling

    International Nuclear Information System (INIS)

    Majdara, Aref; Wakabayashi, Toshio

    2008-01-01

    Computer-aided fault tree generation can be easier, faster and less vulnerable to errors than the conventional manual fault tree construction. In this paper, a new approach for algorithmic fault tree generation is presented. The method mainly consists of a component-based system modeling procedure an a trace-back algorithm for fault tree synthesis. Components, as the building blocks of systems, are modeled using function tables and state transition tables. The proposed method can be used for a wide range of systems with various kinds of components, if an inclusive component database is developed. (author)

  7. Signalling network construction for modelling plant defence response.

    Directory of Open Access Journals (Sweden)

    Dragana Miljkovic

    Full Text Available Plant defence signalling response against various pathogens, including viruses, is a complex phenomenon. In resistant interaction a plant cell perceives the pathogen signal, transduces it within the cell and performs a reprogramming of the cell metabolism leading to the pathogen replication arrest. This work focuses on signalling pathways crucial for the plant defence response, i.e., the salicylic acid, jasmonic acid and ethylene signal transduction pathways, in the Arabidopsis thaliana model plant. The initial signalling network topology was constructed manually by defining the representation formalism, encoding the information from public databases and literature, and composing a pathway diagram. The manually constructed network structure consists of 175 components and 387 reactions. In order to complement the network topology with possibly missing relations, a new approach to automated information extraction from biological literature was developed. This approach, named Bio3graph, allows for automated extraction of biological relations from the literature, resulting in a set of (component1, reaction, component2 triplets and composing a graph structure which can be visualised, compared to the manually constructed topology and examined by the experts. Using a plant defence response vocabulary of components and reaction types, Bio3graph was applied to a set of 9,586 relevant full text articles, resulting in 137 newly detected reactions between the components. Finally, the manually constructed topology and the new reactions were merged to form a network structure consisting of 175 components and 524 reactions. The resulting pathway diagram of plant defence signalling represents a valuable source for further computational modelling and interpretation of omics data. The developed Bio3graph approach, implemented as an executable language processing and graph visualisation workflow, is publically available at http://ropot.ijs.si/bio3graph/and can be

  8. PopPlanner: Visually constructing demographic models for simulation

    Directory of Open Access Journals (Sweden)

    Gregory Bruce Ewing

    2015-04-01

    Full Text Available Currently there are a number of coalescent simulation programs that support a wide range of features, such as arbitrary demographic models, migration, and sub structure. Defining the model is done typically with either text files or command line switches. Although this has proven to be a powerful method of defining models of high complexity, it is often error prone and difficult to read without familiarity both with command lines and the program in question. A intuitive GUI based population structure program that can both read and write applicable command lines would dramatically simplify the construction, modification, and error checking of such models by a wider user base.Results: PopPlanner is a tool to both construct and inspect complicated demographic models visually with a GUI where the user’s primary interaction is through mouse gestures. Because of their popularity, we focus on ms and by extension msms, command line coalescent simulation programs. Our program can be used to find errors with existing command lines, or to build original command lines. Furthermore the graphical output supports a number of editing and output features including export of publication quality figures.

  9. Construction of UML class diagram with Model-Driven Development

    Directory of Open Access Journals (Sweden)

    Tomasz Górski

    2016-03-01

    Full Text Available Model transformations play a key role in software development projects based on Model--Driven Development (MDD principles. Transformations allow for automation of repetitive and well-defined steps, thus shortening design time and reducing a number of errors. In the object-oriented approach, the key elements are use cases. They are described, modelled and later designed until executable application code is obtained. The aim of the paper is to present transformation of a model-to-model type, Communication-2-Class, which automates construction of Unified Modelling Language (UML class diagram in the context of the analysis/design model. An UML class diagram is created based on UML communication diagram within use case realization. As a result, a class diagram shows all of the classes involved in the use case realization and the relationships among them. The plug-in which implements Communication-2-Class transformation was implemented in the IBM Rational Software Architect. The article presents the tests results of developed plug-in, which realizes Communication-2-Class transformation, showing capabilities of shortening use case realization’s design time.[b]Keywords[/b]: Model-Driven Development, transformations, Unified Modelling Language, analysis/design model, UML class diagram, UML communication diagram

  10. Modeling of Construction Cost of Villas in Oman

    Directory of Open Access Journals (Sweden)

    MA Al-Mohsin

    2014-06-01

    Full Text Available In this research, a model for estimating construction cost of villas is presented. The model takes into account four major factors affecting villa's cost, namely: built up area, number of toilets, number of bedrooms and the number of stories. A field survey was conducted to collect information required for such model using data collection form designed by the researchers. Information about 150 villas was collected from six well experienced consultants in the field of villa design and supervision in Oman. Collected data was analyzed to develop suggested model which consists of two main levels of estimate. The first level is at the conceptual design stage where the client presents his/her need of space and basic information about the available plot for construction. The second level of cost estimation is carried out after the preliminary design stage where the client has to decide on the finishes and type of structure. At the second level of estimation, the client should be able to decide whether to precede for construction or not, according to his/her budget. The model is general and can be used anywhere and was validated for accepted degree of confidence using the actual cost of the 112 executed villa projects in Oman. The villas included in this study were owned by clients from both high and low income brackets and had different types of finishing material. The developed equations showed good correlation between the selected variables and the actual cost with R2  = 0.79 in the case of conceptual estimate and R2  = 0.601 for preliminary estimate.

  11. Construction of fuzzy spaces and their applications to matrix models

    Science.gov (United States)

    Abe, Yasuhiro

    Quantization of spacetime by means of finite dimensional matrices is the basic idea of fuzzy spaces. There remains an issue of quantizing time, however, the idea is simple and it provides an interesting interplay of various ideas in mathematics and physics. Shedding some light on such an interplay is the main theme of this dissertation. The dissertation roughly separates into two parts. In the first part, we consider rather mathematical aspects of fuzzy spaces, namely, their construction. We begin with a review of construction of fuzzy complex projective spaces CP k (k = 1, 2, · · ·) in relation to geometric quantization. This construction facilitates defining symbols and star products on fuzzy CPk. Algebraic construction of fuzzy CPk is also discussed. We then present construction of fuzzy S 4, utilizing the fact that CP3 is an S2 bundle over S4. Fuzzy S4 is obtained by imposing an additional algebraic constraint on fuzzy CP3. Consequently it is proposed that coordinates on fuzzy S4 are described by certain block-diagonal matrices. It is also found that fuzzy S8 can analogously be constructed. In the second part of this dissertation, we consider applications of fuzzy spaces to physics. We first consider theories of gravity on fuzzy spaces, anticipating that they may offer a novel way of regularizing spacetime dynamics. We obtain actions for gravity on fuzzy S2 and on fuzzy CP3 in terms of finite dimensional matrices. Application to M(atrix) theory is also discussed. With an introduction of extra potentials to the theory, we show that it also has new brane solutions whose transverse directions are described by fuzzy S 4 and fuzzy CP3. The extra potentials can be considered as fuzzy versions of differential forms or fluxes, which enable us to discuss compactification models of M(atrix) theory. In particular, compactification down to fuzzy S4 is discussed and a realistic matrix model of M-theory in four-dimensions is proposed.

  12. Construction of a biodynamic model for Cry protein production studies.

    Science.gov (United States)

    Navarro-Mtz, Ana Karin; Pérez-Guevara, Fermín

    2014-12-01

    Mathematical models have been used from growth kinetic simulation to gen regulatory networks prediction for B. thuringiensis culture. However, this culture is a time dependent dynamic process where cells physiology suffers several changes depending on the changes in the cell environment. Therefore, through its culture, B. thuringiensis presents three phases related with the predominance of three major metabolic pathways: vegetative growth (Embded-Meyerhof-Parnas pathway), transition (γ-aminobutiric cycle) and sporulation (tricarboxylic acid cycle). There is not available a mathematical model that relates the different stages of cultivation with the metabolic pathway active on each one of them. Therefore, in the present study, and based on published data, a biodynamic model was generated to describe the dynamic of the three different phases based on their major metabolic pathways. The biodynamic model is used to study the interrelation between the different culture phases and their relationship with the Cry protein production. The model consists of three interconnected modules where each module represents one culture phase and its principal metabolic pathway. For model validation four new fermentations were done showing that the model constructed describes reasonably well the dynamic of the three phases. The main results of this model imply that poly-β-hydroxybutyrate is crucial for endospore and Cry protein production. According to the yields of dipicolinic acid and Cry from poly-β-hydroxybutyrate, calculated with the model, the endospore and Cry protein production are not just simultaneous and parallel processes they are also competitive processes.

  13. Computer-Aided Construction of Chemical Kinetic Models

    Energy Technology Data Exchange (ETDEWEB)

    Green, William H. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2014-12-31

    The combustion chemistry of even simple fuels can be extremely complex, involving hundreds or thousands of kinetically significant species. The most reasonable way to deal with this complexity is to use a computer not only to numerically solve the kinetic model, but also to construct the kinetic model in the first place. Because these large models contain so many numerical parameters (e.g. rate coefficients, thermochemistry) one never has sufficient data to uniquely determine them all experimentally. Instead one must work in “predictive” mode, using theoretical rather than experimental values for many of the numbers in the model, and as appropriate refining the most sensitive numbers through experiments. Predictive chemical kinetics is exactly what is needed for computer-aided design of combustion systems based on proposed alternative fuels, particularly for early assessment of the value and viability of proposed new fuels before those fuels are commercially available. This project was aimed at making accurate predictive chemical kinetics practical; this is a challenging goal which requires a range of science advances. The project spanned a wide range from quantum chemical calculations on individual molecules and elementary-step reactions, through the development of improved rate/thermo calculation procedures, the creation of algorithms and software for constructing and solving kinetic simulations, the invention of methods for model-reduction while maintaining error control, and finally comparisons with experiment. Many of the parameters in the models were derived from quantum chemistry calculations, and the models were compared with experimental data measured in our lab or in collaboration with others.

  14. Multi-model-based Access Control in Construction Projects

    Directory of Open Access Journals (Sweden)

    Frank Hilbert

    2012-04-01

    Full Text Available During the execution of large scale construction projects performed by Virtual Organizations (VO, relatively complex technical models have to be exchanged between the VO members. For linking the trade and transfer of these models, a so-called multi-model container format was developed. Considering the different skills and tasks of the involved partners, it is not necessary for them to know all the models in every technical detailing. Furthermore, the model size can lead to a delay in communication. In this paper an approach is presented for defining model cut-outs according to the current project context. Dynamic dependencies to the project context as well as static dependencies on the organizational structure are mapped in a context-sensitive rule. As a result, an approach for dynamic filtering of multi-models is obtained which ensures, together with a filtering service, that the involved VO members get a simplified view of complex multi-models as well as sufficient permissions depending on their tasks.

  15. Biomechanical modelling and evaluation of construction jobs for performance improvement.

    Science.gov (United States)

    Parida, Ratri; Ray, Pradip Kumar

    2012-01-01

    Occupational risk factors, such as awkward posture, repetition, lack of rest, insufficient illumination and heavy workload related to construction-related MMH activities may cause musculoskeletal disorders and poor performance of the workers, ergonomic design of construction worksystems was a critical need for improving their health and safety wherein a dynamic biomechanical models were required to be empirically developed and tested at a construction site of Tata Steel, the largest steel making company of India in private sector. In this study, a comprehensive framework is proposed for biomechanical evaluation of shovelling and grinding under diverse work environments. The benefit of such an analysis lies in its usefulness in setting guidelines for designing such jobs with minimization of risks of musculoskeletal disorders (MSDs) and enhancing correct methods of carrying out the jobs leading to reduced fatigue and physical stress. Data based on direct observations and videography were collected for the shovellers and grinders over a number of workcycles. Compressive forces and moments for a number of segments and joints are computed with respect to joint flexion and extension. The results indicate that moments and compressive forces at L5/S1 link are significant for shovellers while moments at elbow and wrist are significant for grinders.

  16. Modeling Manpower and Equipment Productivity in Tall Building Construction Projects

    Science.gov (United States)

    Mudumbai Krishnaswamy, Parthasarathy; Rajiah, Murugasan; Vasan, Ramya

    2017-12-01

    Tall building construction projects involve two critical resources of manpower and equipment. Their usage, however, widely varies due to several factors affecting their productivity. Currently, no systematic study for estimating and increasing their productivity is available. What is prevalent is the use of empirical data, experience of similar projects and assumptions. As tall building projects are here to stay and increase, to meet the emerging demands in ever shrinking urban spaces, it is imperative to explore ways and means of scientific productivity models for basic construction activities: concrete, reinforcement, formwork, block work and plastering for the input of specific resources in a mixed environment of manpower and equipment usage. Data pertaining to 72 tall building projects in India were collected and analyzed. Then, suitable productivity estimation models were developed using multiple linear regression analysis and validated using independent field data. It is hoped that the models developed in the study will be useful for quantity surveyors, cost engineers and project managers to estimate productivity of resources in tall building projects.

  17. The study of the risk management model of construction project

    International Nuclear Information System (INIS)

    Jiang Bo; Feng Yanping; Liu Changbin

    2010-01-01

    The paper first analyzed the development of the risk management of construction project and the risk management processes, and then briefly introduced the risk management experience of foreign project management. From the project management by objectives point of view, the greatest risk came from the lack of clarity of the objectives in the project management, which led to the project's risk emergence. In the analysis of the principles of the project objectives identification and risk allocation, the paper set up a project management model which insurance companies involved in the whole process of the project management, and simply analyzed the roles of insurance company at last. (authors)

  18. Fuzzy pricing for urban water resources: model construction and application.

    Science.gov (United States)

    Zhao, Ranhang; Chen, Shouyu

    2008-08-01

    A rational water price system plays a crucial role in the optimal allocation of water resources. In this paper, a fuzzy pricing model for urban water resources is presented, which consists of a multi-criteria fuzzy evaluation model and a water resources price (WRP) computation model. Various factors affecting WRP are comprehensively evaluated with multiple levels and objectives in the multi-criteria fuzzy evaluation model, while the price vectors of water resources are constructed in the WRP computation model according to the definition of the bearing water price index, and then WRP is calculated. With the incorporation of an operator's knowledge, it considers iterative weights and subjective preference of operators for weight-assessment. The weights determined are more rational and the evaluation results are more realistic. Particularly, dual water supply is considered in the study. Different prices being fixed for water resources with different qualities conforms to the law of water resources value (WRV) itself. A high-quality groundwater price computation model is also proposed to provide optimal water allocation and to meet higher living standards. The developed model is applied in Jinan for evaluating its validity. The method presented in this paper offers some new directions in the research of WRP.

  19. Construction and completion of flux balance models from pathway databases.

    Science.gov (United States)

    Latendresse, Mario; Krummenacker, Markus; Trupp, Miles; Karp, Peter D

    2012-02-01

    Flux balance analysis (FBA) is a well-known technique for genome-scale modeling of metabolic flux. Typically, an FBA formulation requires the accurate specification of four sets: biochemical reactions, biomass metabolites, nutrients and secreted metabolites. The development of FBA models can be time consuming and tedious because of the difficulty in assembling completely accurate descriptions of these sets, and in identifying errors in the composition of these sets. For example, the presence of a single non-producible metabolite in the biomass will make the entire model infeasible. Other difficulties in FBA modeling are that model distributions, and predicted fluxes, can be cryptic and difficult to understand. We present a multiple gap-filling method to accelerate the development of FBA models using a new tool, called MetaFlux, based on mixed integer linear programming (MILP). The method suggests corrections to the sets of reactions, biomass metabolites, nutrients and secretions. The method generates FBA models directly from Pathway/Genome Databases. Thus, FBA models developed in this framework are easily queried and visualized using the Pathway Tools software. Predicted fluxes are more easily comprehended by visualizing them on diagrams of individual metabolic pathways or of metabolic maps. MetaFlux can also remove redundant high-flux loops, solve FBA models once they are generated and model the effects of gene knockouts. MetaFlux has been validated through construction of FBA models for Escherichia coli and Homo sapiens. Pathway Tools with MetaFlux is freely available to academic users, and for a fee to commercial users. Download from: biocyc.org/download.shtml. mario.latendresse@sri.com Supplementary data are available at Bioinformatics online.

  20. HAM Construction modeling using COMSOL with MatLab Modeling Guide version 1.0.

    NARCIS (Netherlands)

    Schijndel, van A.W.M.

    2006-01-01

    This paper presents a first modeling guide for the modeling and simulation of up to full 3D dynamic Heat, Air & Moisture (HAM) transport of building constructions using COMSOL with Matlab. The modeling scripts are provided at the appendix. Furthermore, all modeling files and results are published at

  1. HAM Construction modeling using COMSOL with MatLab Modeling Guide, version 1.0

    NARCIS (Netherlands)

    Schijndel, van A.W.M.

    2006-01-01

    This paper presents a first modeling guide for the modeling and simulation of up to full 3D dynamic Heat, Air & Moisture (HAM) transport of building constructions using COMSOL with Matlab. The modeling scripts are provided at the appendix. Furthermore, all modeling files and results are published at

  2. Training for spacecraft technical analysts

    Science.gov (United States)

    Ayres, Thomas J.; Bryant, Larry

    1989-01-01

    Deep space missions such as Voyager rely upon a large team of expert analysts who monitor activity in the various engineering subsystems of the spacecraft and plan operations. Senior teammembers generally come from the spacecraft designers, and new analysts receive on-the-job training. Neither of these methods will suffice for the creation of a new team in the middle of a mission, which may be the situation during the Magellan mission. New approaches are recommended, including electronic documentation, explicit cognitive modeling, and coached practice with archived data.

  3. Planning Inmarsat's second generation of spacecraft

    Science.gov (United States)

    Williams, W. P.

    1982-09-01

    The next generation of studies of the Inmarsat service are outlined, such as traffic forecasting studies, communications capacity estimates, space segment design, cost estimates, and financial analysis. Traffic forecasting will require future demand estimates, and a computer model has been developed which estimates demand over the Atlantic, Pacific, and Indian ocean regions. Communications estimates are based on traffic estimates, as a model converts traffic demand into a required capacity figure for a given area. The Erlang formula is used, requiring additional data such as peak hour ratios and distribution estimates. Basic space segment technical requirements are outlined (communications payload, transponder arrangements, etc), and further design studies involve such areas as space segment configuration, launcher and spacecraft studies, transmission planning, and earth segment configurations. Cost estimates of proposed design parameters will be performed, but options must be reduced to make construction feasible. Finally, a financial analysis will be carried out in order to calculate financial returns.

  4. Constructing Poverty Lines in Croatia Using Kakwani’s Model

    Directory of Open Access Journals (Sweden)

    Marinko Škare

    2017-06-01

    Full Text Available This paper presents a new model for defining the poverty line as a possible candidate for the construction of a new official poverty line in Croatia. The model, based on Kakwani’s (2010 approach (nutrition-based anchor, uses consumer theory as the basis for defining food and non-food poverty lines. In Croatia, various alternative poverty indicators have been developed to define the official poverty line. To ensure international comparability and consistency, the poverty threshold expressed in local currency by applying the exchange rate of currencies’ purchasing power (PPP is expressed in international dollars. It is important to ensure implementation of redistributive policies, maximization of market efficiency, and increased social justice. All this policy goals and instruments heavily depend on efficient and precise poverty measurement methods.

  5. Construct canine intracranial aneurysm model by endovascular technique

    International Nuclear Information System (INIS)

    Liang Xiaodong; Liu Yizhi; Ni Caifang; Ding Yi

    2004-01-01

    Objective: To construct canine bifurcation aneurysms suitable for evaluating the exploration of endovascular devices for interventional therapy by endovascular technique. Methods: The right common carotid artery of six dogs was expanded with a pliable balloon by means of endovascular technique, then embolization with detached balloon was taken at their originations DAS examination were performed on 1, 2, 3 d after the procedurse. Results: 6 aneurysm models were created in six dogs successfully with the mean width and height of the aneurysms decreasing in 3 days. Conclusions: This canine aneurysm model presents the virtue in the size and shape of human cerebral bifurcation saccular aneurysms on DSA image, suitable for developing the exploration of endovascular devices for aneurismal therapy. The procedure is quick, reliable and reproducible. (authors)

  6. Construction Of A Performance Assessment Model For Zakat Management Institutions

    Directory of Open Access Journals (Sweden)

    Sri Fadilah

    2016-12-01

    Full Text Available The objective of the research is to examine the performance evaluation using Balanced Scorecard model. The research is conducted due to a big gap existing between zakat (alms and religious tax in Islam with its potential earn of as much as 217 trillion rupiahs and the realization of the collected zakat fund that is only reached for three trillion. This indicates that the performance of zakat management organizations in collecting the zakat is still very low. On the other hand, the quantity and the quality of zakat management organizations have to be improved. This means the performance evaluation model as a tool to evaluate performance is needed. The model construct is making a performance evaluation model that can be implemented to zakat management organizations. The organizational performance with Balanced Scorecard evaluation model will be effective if it is supported by three aspects, namely:  PI, BO and TQM. This research uses explanatory method and data analysis tool of SEM/PLS. Data collecting technique are questionnaires, interviews and documentation. The result of this research shows that PI, BO and TQM simultaneously and partially gives a significant effect on organizational performance.

  7. Recurrent Neural Network Model for Constructive Peptide Design.

    Science.gov (United States)

    Müller, Alex T; Hiss, Jan A; Schneider, Gisbert

    2018-02-26

    We present a generative long short-term memory (LSTM) recurrent neural network (RNN) for combinatorial de novo peptide design. RNN models capture patterns in sequential data and generate new data instances from the learned context. Amino acid sequences represent a suitable input for these machine-learning models. Generative models trained on peptide sequences could therefore facilitate the design of bespoke peptide libraries. We trained RNNs with LSTM units on pattern recognition of helical antimicrobial peptides and used the resulting model for de novo sequence generation. Of these sequences, 82% were predicted to be active antimicrobial peptides compared to 65% of randomly sampled sequences with the same amino acid distribution as the training set. The generated sequences also lie closer to the training data than manually designed amphipathic helices. The results of this study showcase the ability of LSTM RNNs to construct new amino acid sequences within the applicability domain of the model and motivate their prospective application to peptide and protein design without the need for the exhaustive enumeration of sequence libraries.

  8. Using Apex To Construct CPM-GOMS Models

    Science.gov (United States)

    John, Bonnie; Vera, Alonso; Matessa, Michael; Freed, Michael; Remington, Roger

    2006-01-01

    process for automatically generating computational models of human/computer interactions as well as graphical and textual representations of the models has been built on the conceptual foundation of a method known in the art as CPM-GOMS. This method is so named because it combines (1) the task decomposition of analysis according to an underlying method known in the art as the goals, operators, methods, and selection (GOMS) method with (2) a model of human resource usage at the level of cognitive, perceptual, and motor (CPM) operations. CPM-GOMS models have made accurate predictions about behaviors of skilled computer users in routine tasks, but heretofore, such models have been generated in a tedious, error-prone manual process. In the present process, CPM-GOMS models are generated automatically from a hierarchical task decomposition expressed by use of a computer program, known as Apex, designed previously to be used to model human behavior in complex, dynamic tasks. An inherent capability of Apex for scheduling of resources automates the difficult task of interleaving the cognitive, perceptual, and motor resources that underlie common task operators (e.g., move and click mouse). The user interface of Apex automatically generates Program Evaluation Review Technique (PERT) charts, which enable modelers to visualize the complex parallel behavior represented by a model. Because interleaving and the generation of displays to aid visualization are automated, it is now feasible to construct arbitrarily long sequences of behaviors. The process was tested by using Apex to create a CPM-GOMS model of a relatively simple human/computer-interaction task and comparing the time predictions of the model and measurements of the times taken by human users in performing the various steps of the task. The task was to withdraw $80 in cash from an automated teller machine (ATM). For the test, a Visual Basic mockup of an ATM was created, with a provision for input from (and measurement

  9. Spacecraft Spin Test Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Provides the capability to correct unbalances of spacecraft by using dynamic measurement techniques and static/coupled measurements to provide products of...

  10. Short Wavelength Electromagnetic Perturbations Excited Near the Solar Probe Plus Spacecraft in the Inner Heliosphere: 2.5D Hybrid Modeling

    Science.gov (United States)

    Lipatov, Alexander S.; Sittler, Edward C.; Hartle, Richard E.; Cooper, John F.

    2011-01-01

    A 2.5D numerical plasma model of the interaction of the solar wind (SW) with the Solar Probe Plus spacecraft (SPPSC) is presented. These results should be interpreted as a basic plasma model derived from the SW-interaction with the spacecraft (SC), which could have consequences for both plasma wave and electron plasma measurements on board the SC in the inner heliosphere. Compression waves and electric field jumps with amplitudes of about 1.5 V/m and (12-18) V/m were also observed. A strong polarization electric field was also observed in the wing of the plasma wake. However, 2.5D hybrid modeling did not show excitation of whistler/Alfven waves in the upstream connected with the bidirectional current closure that was observed in short-time 3D modeling SPPSC and near a tether in the ionosphere. The observed strong electromagnetic perturbations may be a crucial point in the electromagnetic measurements planned for the future Solar Probe Plus (SPP) mission. The results of modeling electromagnetic field perturbations in the SW due to shot noise in absence of SPPSC are also discussed.

  11. THE INVESTMENT MODEL OF THE CONSTRUCTION OF PUBLIC OBJECTS

    Directory of Open Access Journals (Sweden)

    Reperger Šandor

    2009-11-01

    Full Text Available One of the possible models of the construction and use of sports objects, especi- ally indoor facilities (sports centres, halls, swimming pools, shooting alleys and others is the cooperation of the public and private sector, by the investment model of PPP (Pu- blic-Private Partnership. PPP (Public-Private Partnership construction is the new form of securing civil works, already known in the developed countries, in which the job of planning, construc- tion, functioning and financing is done by the private sector – in the scope of a precisely elaborated cooperation with the state. The state engages the private sector for the administering of the civil works. By public adverstisements and contests they will find the investors who accept the administe- ring of certain public works by themselves or with the help of project partners with their own resources (with 60-85% of bank loans, secure the conditions for conducting certain services (by using the objects, halls, etc until the expiration of the agreed deadline. The essence of PPP construction is the fact that an investor from the private sec- tor, chosen through a contest, realizes the project using its own means. The object beco- mes the property of the investor and it secures the regular functioning of the object with exclusive rights. The income from the functioning belongs to the investor, in return the costs of the functioning of the object, the upkeep, as well as the costs of the personnel and public utilities are the responsibility of the investor. The public use of the object is realised by the means that the authorised ministry and the partner from the contest in an agreement of the realization and functioning of the object accurately define the time of maintenance and the duration of the services on the behalf of social interest. From the time specified in the agreement the investor doesn’t charge precisely defined users for general and specific services. As Sebia, with all its

  12. A new approach for modelling variability in residential construction projects

    Directory of Open Access Journals (Sweden)

    Mehrdad Arashpour

    2013-06-01

    Full Text Available The construction industry is plagued by long cycle times caused by variability in the supply chain. Variations or undesirable situations are the result of factors such as non-standard practices, work site accidents, inclement weather conditions and faults in design. This paper uses a new approach for modelling variability in construction by linking relative variability indicators to processes. Mass homebuilding sector was chosen as the scope of the analysis because data is readily available. Numerous simulation experiments were designed by varying size of capacity buffers in front of trade contractors, availability of trade contractors, and level of variability in homebuilding processes. The measurements were shown to lead to an accurate determination of relationships between these factors and production parameters. The variability indicator was found to dramatically affect the tangible performance measures such as home completion rates. This study provides for future analysis of the production homebuilding sector, which may lead to improvements in performance and a faster product delivery to homebuyers.

  13. A new approach for modelling variability in residential construction projects

    Directory of Open Access Journals (Sweden)

    Mehrdad Arashpour

    2013-06-01

    Full Text Available The construction industry is plagued by long cycle times caused by variability in the supply chain. Variations or undesirable situations are the result of factors such as non-standard practices, work site accidents, inclement weather conditions and faults in design. This paper uses a new approach for modelling variability in construction by linking relative variability indicators to processes. Mass homebuilding sector was chosen as the scope of the analysis because data is readily available. Numerous simulation experiments were designed by varying size of capacity buffers in front of trade contractors, availability of trade contractors, and level of variability in homebuilding processes. The measurements were shown to lead to an accurate determination of relationships between these factors and production parameters. The variability indicator was found to dramatically affect the tangible performance measures such as home completion rates. This study provides for future analysis of the production homebuilding sector, which may lead to improvements in performance and a faster product delivery to homebuyers. 

  14. Using temporal information to construct, update, and retrieve situation models of narratives

    NARCIS (Netherlands)

    Rinck, M.; Hähnel, A.; Becker, G.

    2001-01-01

    Four experiments explored how readers use temporal information to construct and update situation models and retrieve them from memory. In Experiment 1, readers spontaneously constructed temporal and spatial situation models of single sentences. In Experiment 2, temporal inconsistencies caused

  15. Developing a Physiologically-Based Pharmacokinetic Model Knowledgebase in Support of Provisional Model Construction

    Science.gov (United States)

    Grulke, Christopher M.; Chang, Daniel T.; Brooks, Raina D.; Leonard, Jeremy A.; Phillips, Martin B.; Hypes, Ethan D.; Fair, Matthew J.; Tornero-Velez, Rogelio; Johnson, Jeffre; Dary, Curtis C.; Tan, Yu-Mei

    2016-01-01

    Developing physiologically-based pharmacokinetic (PBPK) models for chemicals can be resource-intensive, as neither chemical-specific parameters nor in vivo pharmacokinetic data are easily available for model construction. Previously developed, well-parameterized, and thoroughly-vetted models can be a great resource for the construction of models pertaining to new chemicals. A PBPK knowledgebase was compiled and developed from existing PBPK-related articles and used to develop new models. From 2,039 PBPK-related articles published between 1977 and 2013, 307 unique chemicals were identified for use as the basis of our knowledgebase. Keywords related to species, gender, developmental stages, and organs were analyzed from the articles within the PBPK knowledgebase. A correlation matrix of the 307 chemicals in the PBPK knowledgebase was calculated based on pharmacokinetic-relevant molecular descriptors. Chemicals in the PBPK knowledgebase were ranked based on their correlation toward ethylbenzene and gefitinib. Next, multiple chemicals were selected to represent exact matches, close analogues, or non-analogues of the target case study chemicals. Parameters, equations, or experimental data relevant to existing models for these chemicals and their analogues were used to construct new models, and model predictions were compared to observed values. This compiled knowledgebase provides a chemical structure-based approach for identifying PBPK models relevant to other chemical entities. Using suitable correlation metrics, we demonstrated that models of chemical analogues in the PBPK knowledgebase can guide the construction of PBPK models for other chemicals. PMID:26871706

  16. Application of 3D model in the schedule management of nuclear power plant construction

    International Nuclear Information System (INIS)

    Nian Fayang

    2009-01-01

    While 3D technology has been widely used in engineering design, the 3D model of engineering design also includes information that can be used to construction. By the visual interface, the 3D model can be used in different aspects of construction. By linking the 3D model with the construction schedule, the 4D model can be created, through which the visual manage of the construction schedule can be achieved. (authors)

  17. Force-dynamic cultural models in a scalar adjectival construction

    DEFF Research Database (Denmark)

    Jensen, Kim Ebensgaard

    MAG NationalGeographic) (3) If the making of a revolution is drama, punctuated with tragedies too numerous to count, making peace is long-form prose requiring iterations of conversation between people. (COCA 2011 MAG TechReview) (4) I'm too young to get married. (COCA 2011 FIC Callaloo) (5) I......'m in a certain group that's almost too old to hire. (COCA 2011 NEWS Denver) (6) Mr. Turman insisted he was too busy to meet at any other time. (COCA 2011 NEWS NYTimes) In all instances, semantic relations of force-dynamics are set up between the adjective and verb positions, such that the adjective describes...... that the constructional semantics may interact with underlying cultural models (Holland & Quinn 1987, Ungerer & Schmid 2006: 51-59) of force-dynamics or causation (d'Andrade 1987: 117-118). In their study of the English into-causative, Gries & Stefanowitsch (2004: 232-234) suggest that collexeme combinations...

  18. Design, Construction, and Modeling of a 252Cf Neutron Irradiator

    Directory of Open Access Journals (Sweden)

    Blake C. Anderson

    2016-01-01

    Full Text Available Neutron production methods are an integral part of research and analysis for an array of applications. This paper examines methods of neutron production, and the advantages of constructing a radioisotopic neutron irradiator assembly using 252Cf. Characteristic neutron behavior and cost-benefit comparative analysis between alternative modes of neutron production are also examined. The irradiator is described from initial conception to the finished design. MCNP modeling shows a total neutron flux of 3 × 105 n/(cm2·s in the irradiation chamber for a 25 μg source. Measurements of the gamma-ray and neutron dose rates near the external surface of the irradiator assembly are 120 μGy/h and 30 μSv/h, respectively, during irradiation. At completion of the project, total material, and labor costs remained below $50,000.

  19. 3D design terrain models for construction plans and GPS control of highway construction equipment.

    Science.gov (United States)

    2010-03-01

    Research was conducted with the objectives of 1) identifying and characterizing benefits and technological, institutional, cultural, and : legal impediments associated with adoption of 3D design and construction technologies, identifying strategies t...

  20. Activities of the Center for Space Construction

    Science.gov (United States)

    1993-01-01

    The Center for Space Construction (CSC) at the University of Colorado at Boulder is one of eight University Space Engineering Research Centers established by NASA in 1988. The mission of the center is to conduct research into space technology and to directly contribute to space engineering education. The center reports to the Department of Aerospace Engineering Sciences and resides in the College of Engineering and Applied Science. The college has a long and successful track record of cultivating multi-disciplinary research and education programs. The Center for Space Construction is prominent evidence of this record. At the inception of CSC, the center was primarily founded on the need for research on in-space construction of large space systems like space stations and interplanetary space vehicles. The scope of CSC's research has now evolved to include the design and construction of all spacecraft, large and small. Within this broadened scope, our research projects seek to impact the underlying technological basis for such spacecraft as remote sensing satellites, communication satellites, and other special purpose spacecraft, as well as the technological basis for large space platforms. The center's research focuses on three areas: spacecraft structures, spacecraft operations and control, and regolith and surface systems. In the area of spacecraft structures, our current emphasis is on concepts and modeling of deployable structures, analysis of inflatable structures, structural damage detection algorithms, and composite materials for lightweight structures. In the area of spacecraft operations and control, we are continuing our previous efforts in process control of in-orbit structural assembly. In addition, we have begun two new efforts in formal approach to spacecraft flight software systems design and adaptive attitude control systems. In the area of regolith and surface systems, we are continuing the work of characterizing the physical properties of lunar

  1. Spacecraft Charge Monitor

    Science.gov (United States)

    Goembel, L.

    2003-12-01

    We are currently developing a flight prototype Spacecraft Charge Monitor (SCM) with support from NASA's Small Business Innovation Research (SBIR) program. The device will use a recently proposed high energy-resolution electron spectroscopic technique to determine spacecraft floating potential. The inspiration for the technique came from data collected by the Atmosphere Explorer (AE) satellites in the 1970s. The data available from the AE satellites indicate that the SCM may be able to determine spacecraft floating potential to within 0.1 V under certain conditions. Such accurate measurement of spacecraft charge could be used to correct biases in space plasma measurements. The device may also be able to measure spacecraft floating potential in the solar wind and in orbit around other planets.

  2. Pressure-Fed LOX/LCH4 Reaction Control System for Spacecraft: Transient Modeling and Thermal Vacuum Hotfire Test Results

    Science.gov (United States)

    Atwell, Matthew J.; Hurlbert, Eric A.; Melcher, J. C.; Morehead, Robert L.

    2017-01-01

    An integrated cryogenic liquid oxygen, liquid methane (LOX/LCH4) reaction control system (RCS) was tested at NASA Glenn Research Center's Plum Brook Station in the Spacecraft Propulsion Research Facility (B-2) under vacuum and thermal vacuum conditions. The RCS is a subsystem of the Integrated Cryogenic Propulsion Test Article (ICPTA), a pressure-fed LOX/LCH4 propulsion system composed of a single 2,800 lbf main engine, two 28 lbf RCS engines, and two 7 lbf RCS engines. Propellants are stored in four 48 inch diameter 5083 aluminum tanks that feed both the main engine and RCS engines in parallel. Helium stored cryogenically in a composite overwrapped pressure vessel (COPV) flows through a heat exchanger on the main engine before being used to pressurize the propellant tanks to a design operating pressure of 325 psi. The ICPTA is capable of simultaneous main engine and RCS operation. The RCS engines utilize a coil-on-plug (COP) ignition system designed for operation in a vacuum environment, eliminating corona discharge issues associated with a high voltage lead. There are two RCS pods on the ICPTA, with two engines on each pod. One of these two engines is a heritage flight engine from Project Morpheus. Its sea level nozzle was removed and replaced by an 85:1 nozzle machined using Inconel 718, resulting in a maximum thrust of 28 lbf under altitude conditions. The other engine is a scaled down version of the 28 lbf engine, designed to match the core and overall mixture ratios as well as other injector characteristics. This engine can produce a maximum thrust of 7 lbf with an 85:1 nozzle that was additively manufactured using Inconel 718. Both engines are film-cooled and capable of limited duration gas-gas and gas-liquid operation, as well as steady-state liquid-liquid operation. Each pod contains one of each version, such that two engines of the same thrust level can be fired as a couple on opposite pods. The RCS feed system is composed of symmetrical 3/8 inch lines

  3. Model for setting priority construction project objectives aligned with ...

    African Journals Online (AJOL)

    participants, including contractors, quantity surveyors, project managers, architects, and ..... (2004: 1) report that the global construction industry is plagued with ..... 1.2. Construction consultant/Developer. 2. 1.2. Engineering. 2. 1.2. Logistics. 2. 1.2 ...... supplychain/PPPFA%20-%20media.pdf> [Accessed: 2 June 2011].

  4. Teaching Construction: A Design-Based Course Model

    Science.gov (United States)

    Love, Tyler S.; Salgado, Carlos A.

    2016-01-01

    The focus on construction in T&E education has drastically changed. This article presents a series of topics and design-based labs that can be taught at various grade levels to integrate STEM concepts while also increasing students' overall awareness of construction and structural technologies.

  5. Spacecraft momentum control systems

    CERN Document Server

    Leve, Frederick A; Peck, Mason A

    2015-01-01

    The goal of this book is to serve both as a practical technical reference and a resource for gaining a fuller understanding of the state of the art of spacecraft momentum control systems, specifically looking at control moment gyroscopes (CMGs). As a result, the subject matter includes theory, technology, and systems engineering. The authors combine material on system-level architecture of spacecraft that feature momentum-control systems with material about the momentum-control hardware and software. This also encompasses material on the theoretical and algorithmic approaches to the control of space vehicles with CMGs. In essence, CMGs are the attitude-control actuators that make contemporary highly agile spacecraft possible. The rise of commercial Earth imaging, the advances in privately built spacecraft (including small satellites), and the growing popularity of the subject matter in academic circles over the past decade argues that now is the time for an in-depth treatment of the topic. CMGs are augmented ...

  6. Spacecraft Material Outgassing Data

    Data.gov (United States)

    National Aeronautics and Space Administration — This compilation of outgassing data of materials intended for spacecraft use were obtained at the Goddard Space Flight Center (GSFC), utilizing equipment developed...

  7. Spacecraft Fire Safety Demonstration

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of the Spacecraft Fire Safety Demonstration project is to develop and conduct large-scale fire safety experiments on an International Space Station...

  8. Quick spacecraft charging primer

    International Nuclear Information System (INIS)

    Larsen, Brian Arthur

    2014-01-01

    This is a presentation in PDF format which is a quick spacecraft charging primer, meant to be used for program training. It goes into detail about charging physics, RBSP examples, and how to identify charging.

  9. Theoretical Framework and Model Design for Beautiful Countryside Construction in China

    Directory of Open Access Journals (Sweden)

    ZHENG Xiang-qun

    2015-04-01

    Full Text Available In the context of China today, the process of beautiful countryside construction mainly imitates the patterns of‘urbanization’construction. However, this approach leads to the loss of countryside characteristics and the separation of agricultural culture. Therefore, it's urgent to carry out research of the theoretical framework and model design for beautiful countryside construction. In this paper, based on the analysis of the beautiful countryside construction connotation, the basic theory of beautiful countryside construction was summarized in three aspects: rural complex ecosystem model, multi-functionality of rural model and sustainable development evaluation model. The basic idea of the beautiful countryside construction mode was studied. The design method of beautiful countryside construction mode was proposed in three levels: planning, scheming and evaluating. The research results might offer scientific reference for improving the scientific and operational nature of beautiful countryside construction.

  10. Deployable Brake for Spacecraft

    Science.gov (United States)

    Rausch, J. R.; Maloney, J. W.

    1987-01-01

    Aerodynamic shield that could be opened and closed proposed. Report presents concepts for deployable aerodynamic brake. Brake used by spacecraft returning from high orbit to low orbit around Earth. Spacecraft makes grazing passes through atmosphere to slow down by drag of brake. Brake flexible shield made of woven metal or ceramic withstanding high temperatures created by air friction. Stored until needed, then deployed by set of struts.

  11. Development of test models to quantify encapsulated bioburden in spacecraft polymer materials by cultivation-dependent and molecular methods

    Science.gov (United States)

    Bauermeister, Anja; Moissl-Eichinger, Christine; Mahnert, Alexander; Probst, Alexander; Flier, Niwin; Auerbach, Anna; Weber, Christina; Haberer, Klaus; Boeker, Alexander

    Bioburden encapsulated in spacecraft polymers (such as adhesives and coatings) poses a potential risk to scientific exploration of other celestial bodies, but it is not easily detectable. In this study, we developed novel testing strategies to estimate the quantity of intrinsic encapsulated bioburden in polymers used frequently on spaceflight hardware. In particular Scotch-Weld (TM) 2216 B/A (Epoxy adhesive); MAP SG121FD (Silicone coating), Solithane (®) 113 (Urethane resin); ESP 495 (Silicone adhesive); and Dow Corning (®) 93-500 (Silicone encapsulant) were investigated. As extraction of bioburden from polymerized (solid) materials did not prove feasible, a method was devised to extract contaminants from uncured polymer precursors by dilution in organic solvents. Cultivation-dependent analyses showed less than 0.1-2.5 colony forming units (cfu) per cm³ polymer, whereas quantitative PCR with extracted DNA indicated considerably higher values, despite low DNA extraction efficiency. Results obtained by this method reflected the most conservative proxy for encapsulated bioburden. To observe the effect of physical and chemical stress occurring during polymerization on the viability of encapsulated contaminants, Bacillus safensis spores were embedded close to the surface in cured polymer, which facilitated access for different analytical techniques. Staining by AlexaFluor succinimidyl ester 488 (AF488), propidium monoazide (PMA), CTC (5-cyano-2,3-diotolyl tetrazolium chloride) and subsequent confocal laser scanning microscopy (CLSM) demonstrated that embedded spores retained integrity, germination and cultivation ability even after polymerization of the adhesive Scotch-Weld™ 2216 B/A.

  12. Reference Models of Information Systems Constructed with the use of Technologies of Cloud Calculations

    Directory of Open Access Journals (Sweden)

    Darya Sergeevna Simonenkova

    2013-09-01

    Full Text Available The subject of the research is analysis of various models of the information system constructed with the use of technologies of cloud calculations. Analysis of models is required for constructing a new reference model which will be used for develop a security threats model.

  13. Preliminary study on enhancing waste management best practice model in Malaysia construction industry

    Science.gov (United States)

    Jamaludin, Amril Hadri; Karim, Nurulzatushima Abdul; Noor, Raja Nor Husna Raja Mohd; Othman, Nurulhidayah; Malik, Sulaiman Abdul

    2017-08-01

    Construction waste management (CWM) is the practice of minimizing and diverting construction waste, demolition debris, and land-clearing debris from disposal and redirecting recyclable resources back into the construction process. Best practice model means best choice from the collection of other practices that was built for purpose of construction waste management. The practice model can help the contractors in minimizing waste before the construction activities will be started. The importance of minimizing wastage will have direct impact on time, cost and quality of a construction project. This paper is focusing on the preliminary study to determine the factors of waste generation in the construction sites and identify the effectiveness of existing construction waste management practice conducted in Malaysia. The paper will also include the preliminary works of planned research location, data collection method, and analysis to be done by using the Analytical Hierarchy Process (AHP) to help in developing suitable waste management best practice model that can be used in the country.

  14. Internet Technology on Spacecraft

    Science.gov (United States)

    Rash, James; Parise, Ron; Hogie, Keith; Criscuolo, Ed; Langston, Jim; Powers, Edward I. (Technical Monitor)

    2000-01-01

    The Operating Missions as Nodes on the Internet (OMNI) project has shown that Internet technology works in space missions through a demonstration using the UoSAT-12 spacecraft. An Internet Protocol (IP) stack was installed on the orbiting UoSAT-12 spacecraft and tests were run to demonstrate Internet connectivity and measure performance. This also forms the basis for demonstrating subsequent scenarios. This approach provides capabilities heretofore either too expensive or simply not feasible such as reconfiguration on orbit. The OMNI project recognized the need to reduce the risk perceived by mission managers and did this with a multi-phase strategy. In the initial phase, the concepts were implemented in a prototype system that includes space similar components communicating over the TDRS (space network) and the terrestrial Internet. The demonstration system includes a simulated spacecraft with sample instruments. Over 25 demonstrations have been given to mission and project managers, National Aeronautics and Space Administration (NASA), Department of Defense (DoD), contractor technologists and other decisions makers, This initial phase reached a high point with an OMNI demonstration given from a booth at the Johnson Space Center (JSC) Inspection Day 99 exhibition. The proof to mission managers is provided during this second phase with year 2000 accomplishments: testing the use of Internet technologies onboard an actual spacecraft. This was done with a series of tests performed using the UoSAT-12 spacecraft. This spacecraft was reconfigured on orbit at very low cost. The total period between concept and the first tests was only 6 months! On board software was modified to add an IP stack to support basic IP communications. Also added was support for ping, traceroute and network timing protocol (NTP) tests. These tests show that basic Internet functionality can be used onboard spacecraft. The performance of data was measured to show no degradation from current

  15. Mechanical Design of Spacecraft

    Science.gov (United States)

    1962-01-01

    In the spring of 1962, engineers from the Engineering Mechanics Division of the Jet Propulsion Laboratory gave a series of lectures on spacecraft design at the Engineering Design seminars conducted at the California Institute of Technology. Several of these lectures were subsequently given at Stanford University as part of the Space Technology seminar series sponsored by the Department of Aeronautics and Astronautics. Presented here are notes taken from these lectures. The lectures were conceived with the intent of providing the audience with a glimpse of the activities of a few mechanical engineers who are involved in designing, building, and testing spacecraft. Engineering courses generally consist of heavily idealized problems in order to allow the more efficient teaching of mathematical technique. Students, therefore, receive a somewhat limited exposure to actual engineering problems, which are typified by more unknowns than equations. For this reason it was considered valuable to demonstrate some of the problems faced by spacecraft designers, the processes used to arrive at solutions, and the interactions between the engineer and the remainder of the organization in which he is constrained to operate. These lecture notes are not so much a compilation of sophisticated techniques of analysis as they are a collection of examples of spacecraft hardware and associated problems. They will be of interest not so much to the experienced spacecraft designer as to those who wonder what part the mechanical engineer plays in an effort such as the exploration of space.

  16. Best practices for system dynamics model design and construction with powersim studio.

    Energy Technology Data Exchange (ETDEWEB)

    Malczynski, Leonard A.

    2011-06-01

    This guide addresses software quality in the construction of Powersim{reg_sign} Studio 8 system dynamics simulation models. It is the result of almost ten years of experience with the Powersim suite of system dynamics modeling tools (Constructor and earlier Studio versions). It is a guide that proposes a common look and feel for the construction of Powersim Studio system dynamics models.

  17. A Model Suggestion to Predict Leverage Ratio for Construction Projects

    OpenAIRE

    Özlem Tüz; Şafak Ebesek

    2013-01-01

    Due to the nature, construction is an industry with high uncertainty and risk. Construction industry carries high leverage ratios. Firms with low equities work in big projects through progress payment system, but in this case, even a small negative in the planned cash flows constitute a major risk for the company.The use of leverage, with a small investment to achieve profit targets large-scale, high-profit, but also brings a high risk with it. Investors may lose all or the portion of th...

  18. Constructing service-oriented architecture adoption maturity matrix using Kano model

    Science.gov (United States)

    Hamzah, Mohd Hamdi Irwan; Baharom, Fauziah; Mohd, Haslina

    2017-10-01

    Commonly, organizations adopted Service-Oriented Architecture (SOA) because it can provide a flexible reconfiguration and can reduce the development time and cost. In order to guide the SOA adoption, previous industry and academia have constructed SOA maturity model. However, there is a limited number of works on how to construct the matrix in the previous SOA maturity model. Therefore, this study is going to provide a method that can be used in order to construct the matrix in the SOA maturity model. This study adapts Kano Model to construct the cross evaluation matrix focused on SOA adoption IT and business benefits. This study found that Kano Model can provide a suitable and appropriate method for constructing the cross evaluation matrix in SOA maturity model. Kano model also can be used to plot, organize and better represent the evaluation dimension for evaluating the SOA adoption.

  19. Risk assessment and model for community-based construction ...

    African Journals Online (AJOL)

    It, therefore, becomes necessary to systematically manage uncertainty in community-based construction in order to increase the likelihood of meeting project objectives using necessary risk management strategies. Risk management, which is an iterative process due to the dynamic nature of many risks, follows three main ...

  20. Constructive Alignment for Teaching Model-Based Design for Concurrency

    DEFF Research Database (Denmark)

    Brabrand, Claus

    2007-01-01

    "How can we make sure our students learn what we want them to?" is the number one question in teaching. This paper is intended to provide the reader with: i) a general answer to this question based on the theory of constructive alignment by John Biggs; ii) relevant insights for bringing this answer...

  1. Models in the construction of female identity in Nigerian postcolonial ...

    African Journals Online (AJOL)

    Gendered identity in Africa has for centuries been a hotbed of ideological and narrative contestations. While colonial constructions of the African female were generally essentialist and negative in character, early postcolonial African literature also ironically deployed essentialisms and rigid gender binaries to portray African ...

  2. A Public Commissioning Maturity Model for Construction Clients

    NARCIS (Netherlands)

    Hermans, M.H.; Volker, L.; Eisma, P.R.

    2014-01-01

    Being a public organization with construction needs, whether they are housing, building or infrastructure related, implies close co-operation and interaction with the supply chain. Substantial research exists that focuses on project related aspects of commissioning and on the role of the

  3. Distributed object models for collaboration in the construction industry

    NARCIS (Netherlands)

    Leeuwen, van J.P.; Zee, van der A.

    2005-01-01

    Abstract Information about products for the construction industry is increasingly often provided to designers in digital ways that enable them to apply the information directly in the design process. Digital product catalogues are provided using various media and formats and several initiatives are

  4. A Distributed Object Model for CSCW in the Construction Industry

    NARCIS (Netherlands)

    Leeuwen, van J.P.; Zee, van der A.; Maas, G.; Gassel, F.

    2003-01-01

    Information about products for the construction industry is increasingly often provided to designers in digital ways that enable them to apply the information directly in the design process. Digital product catalogues are provided using various media and formats and several initiatives are taken by

  5. Applications of building information model (BIM) in Malaysian construction industry

    Science.gov (United States)

    Tahir, M. M.; Haron, N. A.; Alias, A. H.; Al-Jumaa, A. T.; Muhammad, I. B.; Harun, A. N.

    2017-12-01

    Since the introduction of BIM in Malaysia in 2009, the technology adoption rate is slow when compared to other countries of the world. Most of the construction companies in Malaysia have an insight on the BIM concept but are yet to implement it in the management of their construction projects. By the year 2020, the Malaysian government will make BIM mandatory, this makes it important to carry out research on the possible applications of the technology. A qualitative method of enquiry was used for this study in Klang Valley using semistructured interview. The responses received were analysed using Principal component analysis (PCA). The result of the analysis showed that “quantity take-off and estimation”, “clash detection and coordination”, “integration and collaboration of stakeholders”, and “design and visualisation” as the main applications of BIM in Malaysia presently. The implication of this findings is that the Malaysian construction industry productivity is likely to increase to meet the demand of the population through the implementations of BIM. More also, BIM technology is regarded as the future of construction industry, which makes it very important for the industry.

  6. A diagnostic ontological model for damages to historical constructions

    Czech Academy of Sciences Publication Activity Database

    Cacciotti, Riccardo; Blaško, M.; Valach, Jaroslav

    2015-01-01

    Roč. 16, č. 1 (2015), s. 40-48 ISSN 1296-2074 R&D Projects: GA MK(CZ) DF11P01OVV002 Keywords : historical constructions * conservation * ontologies * damage Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 1.533, year: 2015 http://www.sciencedirect.com/science/article/pii/S1296207414000259

  7. Revamping Spacecraft Operational Intelligence

    Science.gov (United States)

    Hwang, Victor

    2012-01-01

    The EPOXI flight mission has been testing a new commercial system, Splunk, which employs data mining techniques to organize and present spacecraft telemetry data in a high-level manner. By abstracting away data-source specific details, Splunk unifies arbitrary data formats into one uniform system. This not only reduces the time and effort for retrieving relevant data, but it also increases operational visibility by allowing a spacecraft team to correlate data across many different sources. Splunk's scalable architecture coupled with its graphing modules also provide a solid toolset for generating data visualizations and building real-time applications such as browser-based telemetry displays.

  8. Dips spacecraft integration issues

    International Nuclear Information System (INIS)

    Determan, W.R.; Harty, R.B.

    1988-01-01

    The Department of Energy, in cooperation with the Department of Defense, has recently initiated the dynamic isotope power system (DIPS) demonstration program. DIPS is designed to provide 1 to 10 kW of electrical power for future military spacecraft. One of the near-term missions considered as a potential application for DIPS was the boost surveillance and tracking system (BSTS). A brief review and summary of the reasons behind a selection of DIPS for BSTS-type missions is presented. Many of these are directly related to spacecraft integration issues; these issues will be reviewed in the areas of system safety, operations, survivability, reliability, and autonomy

  9. Contemporary state of spacecraft/environment interaction research

    CERN Document Server

    Novikov, L S

    1999-01-01

    Various space environment effects on spacecraft materials and equipment, and the reverse effects of spacecrafts and rockets on space environment are considered. The necessity of permanent updating and perfection of our knowledge on spacecraft/environment interaction processes is noted. Requirements imposed on models of space environment in theoretical and experimental researches of various aspects of the spacecraft/environment interaction problem are formulated. In this field, main problems which need to be solved today and in the nearest future are specified. The conclusion is made that the joint analysis of both aspects of spacecraft/environment interaction problem promotes the most effective solution of the problem.

  10. Sunlight reflection off the spacecraft with a solar sail on the surface of mars

    Science.gov (United States)

    Starinova, O. L.; Rozhkov, M. A.; Gorbunova, I. V.

    2018-05-01

    Modern technologies make it possible to fulfill many projects in the field of space exploration. One such project is the colonization of Mars and providing favorable conditions for living on it. Authors propose principles of functioning of the spacecraft with a solar sail, intended to create a thermal and light spot in a predetermined area of the Martian surface. This additional illumination can maintain and support certain climatic conditions on a small area where a Mars base could be located. This paper investigate the possibility of the spacecraft continuously reflect the sunlight off the solar sail on the small area of the Mars surface. The mathematical motion model in such condition of the solar sail's orientation is considered and used for motion simulation session. Moreover, the analysis of this motion is performed. Thus, were obtained parameters of the synchronic non-Keplerian orbit and spacecraft construction. In addition, were given recommendations for further applying satellites to reflect the sunlight on a planet's surface.

  11. Industry perspectives on Plug-& -Play Spacecraft Avionics

    Science.gov (United States)

    Franck, R.; Graven, P.; Liptak, L.

    This paper describes the methodologies and findings from an industry survey of awareness and utility of Spacecraft Plug-& -Play Avionics (SPA). The survey was conducted via interviews, in-person and teleconference, with spacecraft prime contractors and suppliers. It focuses primarily on AFRL's SPA technology development activities but also explores the broader applicability and utility of Plug-& -Play (PnP) architectures for spacecraft. Interviews include large and small suppliers as well as large and small spacecraft prime contractors. Through these “ product marketing” interviews, awareness and attitudes can be assessed, key technical and market barriers can be identified, and opportunities for improvement can be uncovered. Although this effort focuses on a high-level assessment, similar processes can be used to develop business cases and economic models which may be necessary to support investment decisions.

  12. Convolution product construction of interactions in probabilistic physical models

    International Nuclear Information System (INIS)

    Ratsimbarison, H.M.; Raboanary, R.

    2007-01-01

    This paper aims to give a probabilistic construction of interactions which may be relevant for building physical theories such as interacting quantum field theories. We start with the path integral definition of partition function in quantum field theory which recall us the probabilistic nature of this physical theory. From a Gaussian law considered as free theory, an interacting theory is constructed by nontrivial convolution product between the free theory and an interacting term which is also a probability law. The resulting theory, again a probability law, exhibits two proprieties already present in nowadays theories of interactions such as Gauge theory : the interaction term does not depend on the free term, and two different free theories can be implemented with the same interaction.

  13. Constructing a Measurement in Service Quality for Indian Banks: Structural Equation Modeling Approach

    OpenAIRE

    Anil Kumar; Manoj Kumar Dash

    2013-01-01

    The aim of this paper is to construct a measure in service quality for Indian banks and establishes a causal relationship of service attributes performance with customer satisfaction. The SERVQUAL model is used. The quantification of service quality led to the attempt to construct an index. The index is constructed using Structural Equation Modeling (SEM) and American Customer Satisfaction Index (ACSI) as the underlying frameworks. The analysis is based on data of 200 bank customers from the ...

  14. Query construction, entropy, and generalization in neural-network models

    Science.gov (United States)

    Sollich, Peter

    1994-05-01

    We study query construction algorithms, which aim at improving the generalization ability of systems that learn from examples by choosing optimal, nonredundant training sets. We set up a general probabilistic framework for deriving such algorithms from the requirement of optimizing a suitable objective function; specifically, we consider the objective functions entropy (or information gain) and generalization error. For two learning scenarios, the high-low game and the linear perceptron, we evaluate the generalization performance obtained by applying the corresponding query construction algorithms and compare it to training on random examples. We find qualitative differences between the two scenarios due to the different structure of the underlying rules (nonlinear and ``noninvertible'' versus linear); in particular, for the linear perceptron, random examples lead to the same generalization ability as a sequence of queries in the limit of an infinite number of examples. We also investigate learning algorithms which are ill matched to the learning environment and find that, in this case, minimum entropy queries can in fact yield a lower generalization ability than random examples. Finally, we study the efficiency of single queries and its dependence on the learning history, i.e., on whether the previous training examples were generated randomly or by querying, and the difference between globally and locally optimal query construction.

  15. Model of investment appraisal of high-rise construction with account of cost of land resources

    Science.gov (United States)

    Okolelova, Ella; Shibaeva, Marina; Trukhina, Natalya

    2018-03-01

    The article considers problems and potential of high-rise construction as a global urbanization. The results of theoretical and practical studies on the appraisal of investments in high-rise construction are provided. High-rise construction has a number of apparent upsides in modern terms of development of megapolises and primarily it is economically efficient. Amid serious lack of construction sites, skyscrapers successfully deal with the need of manufacturing, office and living premises. Nevertheless, there are plenty issues, which are related with high-rise construction, and only thorough scrutiny of them allow to estimate the real economic efficiency of this branch. The article focuses on the question of economic efficiency of high-rise construction. The suggested model allows adjusting the parameters of a facility under construction, setting the tone for market value as well as the coefficient for appreciation of the construction net cost, that depends on the number of storey's, in the form of function or discrete values.

  16. A Model of Desired Performance in Phylogenetic Tree Construction for Teaching Evolution.

    Science.gov (United States)

    Brewer, Steven D.

    This research paper examines phylogenetic tree construction-a form of problem solving in biology-by studying the strategies and heuristics used by experts. One result of the research is the development of a model of desired performance for phylogenetic tree construction. A detailed description of the model and the sample problems which illustrate…

  17. Quantifying uncertainty of geological 3D layer models, constructed with a-priori geological expertise

    NARCIS (Netherlands)

    Gunnink, J.J.; Maljers, D.; Hummelman, J.

    2010-01-01

    Uncertainty quantification of geological models that are constructed with additional geological expert-knowledge is not straightforward. To construct sound geological 3D layer models we use a lot of additional knowledge, with an uncertainty that is hard to quantify. Examples of geological expert

  18. Teachers' Use of Computational Tools to Construct and Explore Dynamic Mathematical Models

    Science.gov (United States)

    Santos-Trigo, Manuel; Reyes-Rodriguez, Aaron

    2011-01-01

    To what extent does the use of computational tools offer teachers the possibility of constructing dynamic models to identify and explore diverse mathematical relations? What ways of reasoning or thinking about the problems emerge during the model construction process that involves the use of the tools? These research questions guided the…

  19. Conceptual Design of Simulation Models in an Early Development Phase of Lunar Spacecraft Simulator Using SMP2 Standard

    Science.gov (United States)

    Lee, Hoon Hee; Koo, Cheol Hea; Moon, Sung Tae; Han, Sang Hyuck; Ju, Gwang Hyeok

    2013-08-01

    The conceptual study for Korean lunar orbiter/lander prototype has been performed in Korea Aerospace Research Institute (KARI). Across diverse space programs around European countries, a variety of simulation application has been developed using SMP2 (Simulation Modelling Platform) standard related to portability and reuse of simulation models by various model users. KARI has not only first-hand experience of a development of SMP compatible simulation environment but also an ongoing study to apply the SMP2 development process of simulation model to a simulator development project for lunar missions. KARI has tried to extend the coverage of the development domain based on SMP2 standard across the whole simulation model life-cycle from software design to its validation through a lunar exploration project. Figure. 1 shows a snapshot from a visualization tool for the simulation of lunar lander motion. In reality, a demonstrator prototype on the right-hand side of image was made and tested in 2012. In an early phase of simulator development prior to a kick-off start in the near future, targeted hardware to be modelled has been investigated and indentified at the end of 2012. The architectural breakdown of the lunar simulator at system level was performed and the architecture with a hierarchical tree of models from the system to parts at lower level has been established. Finally, SMP Documents such as Catalogue, Assembly, Schedule and so on were converted using a XML(eXtensible Mark-up Language) converter. To obtain benefits of the suggested approaches and design mechanisms in SMP2 standard as far as possible, the object-oriented and component-based design concepts were strictly chosen throughout a whole model development process.

  20. Model Construction and Analysis of Respiration in Halobacterium salinarum.

    Directory of Open Access Journals (Sweden)

    Cherryl O Talaue

    Full Text Available The archaeon Halobacterium salinarum can produce energy using three different processes, namely photosynthesis, oxidative phosphorylation and fermentation of arginine, and is thus a model organism in bioenergetics. Compared to its bacteriorhodopsin-driven photosynthesis, less attention has been devoted to modeling its respiratory pathway. We created a system of ordinary differential equations that models its oxidative phosphorylation. The model consists of the electron transport chain, the ATP synthase, the potassium uniport and the sodium-proton antiport. By fitting the model parameters to experimental data, we show that the model can explain data on proton motive force generation, ATP production, and the charge balancing of ions between the sodium-proton antiporter and the potassium uniport. We performed sensitivity analysis of the model parameters to determine how the model will respond to perturbations in parameter values. The model and the parameters we derived provide a resource that can be used for analytical studies of the bioenergetics of H. salinarum.

  1. Model Construction and Analysis of Respiration in Halobacterium salinarum.

    Science.gov (United States)

    Talaue, Cherryl O; del Rosario, Ricardo C H; Pfeiffer, Friedhelm; Mendoza, Eduardo R; Oesterhelt, Dieter

    2016-01-01

    The archaeon Halobacterium salinarum can produce energy using three different processes, namely photosynthesis, oxidative phosphorylation and fermentation of arginine, and is thus a model organism in bioenergetics. Compared to its bacteriorhodopsin-driven photosynthesis, less attention has been devoted to modeling its respiratory pathway. We created a system of ordinary differential equations that models its oxidative phosphorylation. The model consists of the electron transport chain, the ATP synthase, the potassium uniport and the sodium-proton antiport. By fitting the model parameters to experimental data, we show that the model can explain data on proton motive force generation, ATP production, and the charge balancing of ions between the sodium-proton antiporter and the potassium uniport. We performed sensitivity analysis of the model parameters to determine how the model will respond to perturbations in parameter values. The model and the parameters we derived provide a resource that can be used for analytical studies of the bioenergetics of H. salinarum.

  2. Constructing Markov State Models to elucidate the functional conformational changes of complex biomolecules

    KAUST Repository

    Wang, Wei; Cao, Siqin; Zhu, Lizhe; Huang, Xuhui

    2017-01-01

    bioengineering applications and rational drug design. Constructing Markov State Models (MSMs) based on large-scale molecular dynamics simulations has emerged as a powerful approach to model functional conformational changes of the biomolecular system

  3. Spacecraft Dynamics Should be Considered in Kalman Filter Attitude Estimation

    Science.gov (United States)

    Yang, Yaguang; Zhou, Zhiqiang

    2016-01-01

    Kalman filter based spacecraft attitude estimation has been used in some high-profile missions and has been widely discussed in literature. While some models in spacecraft attitude estimation include spacecraft dynamics, most do not. To our best knowledge, there is no comparison on which model is a better choice. In this paper, we discuss the reasons why spacecraft dynamics should be considered in the Kalman filter based spacecraft attitude estimation problem. We also propose a reduced quaternion spacecraft dynamics model which admits additive noise. Geometry of the reduced quaternion model and the additive noise are discussed. This treatment is more elegant in mathematics and easier in computation. We use some simulation example to verify our claims.

  4. Dynamics and control of robotic spacecrafts for the transportation of flexible elements

    International Nuclear Information System (INIS)

    Wen, Hao; Chen, Ti; Yu, Bensong; Jin, Dongping

    2016-01-01

    The technology of robotic spacecrafts has been identified as one of the most appealing solutions to the on-orbit construction of large space structures in future space missions. As a prerequisite of a successful on-orbit construction, it is needed to use small autonomous spacecrafts for the transportation of flexible elements. To this end, the paper presents an energy-based scheme to control a couple of robotic spacecrafts carrying a flexible slender structure to its desired position. The flexible structure is modelled as a long beam based on the formulation of absolute nodal coordinates to account for the geometrical nonlinearity due to large displacement. Meanwhile, the robotic spacecrafts are actuated on their rigid-body degrees of freedom and modelled as two rigid bodies attached to the flexible beam. The energy-based controller is designed using the technique of energy shaping and damping injection such that translational and rotational maneuvers can be achieved with the suppression of the flexible vibrations of the beam. Finally, numerical case studies are performed to demonstrate the proposed schemes. (paper)

  5. Modelling a Global EPCM (Engineering, Procurement and Construction Management Enterprise

    Directory of Open Access Journals (Sweden)

    Sekhar Chattopadhyay

    2010-03-01

    Full Text Available This paper investigates the applicability of enterprise architectures in the context of current business environment by examining the application of Purdue Enterprise Reference Architecture to WorleyParsons, a global engineering, procurement and construction management enterprise, under the backdrop of a similar study carried out on Fluor Daniel during mid-nineties of the last century. The outcome of this study recommends the need for new enterprise architecture, the People-Centric Enterprise Architecture that not only focuses on human dimension in modern enterprises as the central thread, but also includes more business characteristics of the enterprise other than engineerings.

  6. A Stochastic Model of Plausibility in Live Virtual Constructive Environments

    Science.gov (United States)

    2017-09-14

    from the model parameters that are inputs to the computer model ( mathematical model) but whose exact values are unknown to experimentalists and...Environments Jeremy R. Millar Follow this and additional works at: https://scholar.afit.edu/etd Part of the Computer Sciences Commons This Dissertation...25 3.3 Computing Plausibility Exceedance Probabilities . . . . . . . . . . . . . . . . . . . 28 IV

  7. A methodology for constructing the calculation model of scientific spreadsheets

    NARCIS (Netherlands)

    Vos, de M.; Wielemaker, J.; Schreiber, G.; Wielinga, B.; Top, J.L.

    2015-01-01

    Spreadsheets models are frequently used by scientists to analyze research data. These models are typically described in a paper or a report, which serves as single source of information on the underlying research project. As the calculation workflow in these models is not made explicit, readers are

  8. Standardizing the information architecture for spacecraft operations

    Science.gov (United States)

    Easton, C. R.

    1994-01-01

    This paper presents an information architecture developed for the Space Station Freedom as a model from which to derive an information architecture standard for advanced spacecraft. The information architecture provides a way of making information available across a program, and among programs, assuming that the information will be in a variety of local formats, structures and representations. It provides a format that can be expanded to define all of the physical and logical elements that make up a program, add definitions as required, and import definitions from prior programs to a new program. It allows a spacecraft and its control center to work in different representations and formats, with the potential for supporting existing spacecraft from new control centers. It supports a common view of data and control of all spacecraft, regardless of their own internal view of their data and control characteristics, and of their communications standards, protocols and formats. This information architecture is central to standardizing spacecraft operations, in that it provides a basis for information transfer and translation, such that diverse spacecraft can be monitored and controlled in a common way.

  9. Robust Parametric Control of Spacecraft Rendezvous

    Directory of Open Access Journals (Sweden)

    Dake Gu

    2014-01-01

    Full Text Available This paper proposes a method to design the robust parametric control for autonomous rendezvous of spacecrafts with the inertial information with uncertainty. We consider model uncertainty of traditional C-W equation to formulate the dynamic model of the relative motion. Based on eigenstructure assignment and model reference theory, a concise control law for spacecraft rendezvous is proposed which could be fixed through solving an optimization problem. The cost function considers the stabilization of the system and other performances. Simulation results illustrate the robustness and effectiveness of the proposed control.

  10. Research on network information security model and system construction

    OpenAIRE

    Wang Haijun

    2016-01-01

    It briefly describes the impact of large data era on China’s network policy, but also brings more opportunities and challenges to the network information security. This paper reviews for the internationally accepted basic model and characteristics of network information security, and analyses the characteristics of network information security and their relationship. On the basis of the NIST security model, this paper describes three security control schemes in safety management model and the...

  11. A Model-Based Approach to Constructing Music Similarity Functions

    Science.gov (United States)

    West, Kris; Lamere, Paul

    2006-12-01

    Several authors have presented systems that estimate the audio similarity of two pieces of music through the calculation of a distance metric, such as the Euclidean distance, between spectral features calculated from the audio, related to the timbre or pitch of the signal. These features can be augmented with other, temporally or rhythmically based features such as zero-crossing rates, beat histograms, or fluctuation patterns to form a more well-rounded music similarity function. It is our contention that perceptual or cultural labels, such as the genre, style, or emotion of the music, are also very important features in the perception of music. These labels help to define complex regions of similarity within the available feature spaces. We demonstrate a machine-learning-based approach to the construction of a similarity metric, which uses this contextual information to project the calculated features into an intermediate space where a music similarity function that incorporates some of the cultural information may be calculated.

  12. A Multistep Extending Truncation Method towards Model Construction of Infinite-State Markov Chains

    Directory of Open Access Journals (Sweden)

    Kemin Wang

    2014-01-01

    Full Text Available The model checking of Infinite-State Continuous Time Markov Chains will inevitably encounter the state explosion problem when constructing the CTMCs model; our method is to get a truncated model of the infinite one; to get a sufficient truncated model to meet the model checking of Continuous Stochastic Logic based system properties, we propose a multistep extending advanced truncation method towards model construction of CTMCs and implement it in the INFAMY model checker; the experiment results show that our method is effective.

  13. Construction sequence scale model: an aid to productivity and quality assurance

    International Nuclear Information System (INIS)

    Clothier, W.A. Sr.

    1978-01-01

    The natural tendencies of an engineering scale model to promote a high level of quality by error prevention during design and construction stages of a project are studied. A brief section on the basic history of engineering modeling is used to describe TVA's usage of the model. The basic design model is explored in an overview touching the highlights of that form of modeling. A detailed look at the construction sequence model, a relatively new form of model, is presented to demonstrate quality and productivity awareness

  14. Constructing rule-based models using the belief functions framework

    NARCIS (Netherlands)

    Almeida, R.J.; Denoeux, T.; Kaymak, U.; Greco, S.; Bouchon-Meunier, B.; Coletti, G.; Fedrizzi, M.; Matarazzo, B.; Yager, R.R.

    2012-01-01

    Abstract. We study a new approach to regression analysis. We propose a new rule-based regression model using the theoretical framework of belief functions. For this purpose we use the recently proposed Evidential c-means (ECM) to derive rule-based models solely from data. ECM allocates, for each

  15. Causal Indicator Models: Unresolved Issues of Construction and Evaluation

    Science.gov (United States)

    West, Stephen G.; Grimm, Kevin J.

    2014-01-01

    These authors agree with Bainter and Bollen that causal effects represents a useful measurement structure in some applications. The structure of the science of the measurement problem should determine the model; the measurement model should not determine the science. They also applaud Bainter and Bollen's important reminder that the full…

  16. Formulation of Generic Simulation Models for Analyzing Construction Claims

    Directory of Open Access Journals (Sweden)

    Rifat Rustom

    2012-11-01

    Full Text Available While there are several techniques for analyzing the impact of claims on time schedule and productivity,very few are considered adequate and comprehensive to consider risks and uncertainties.A generic approach for claims analysis using simulation is proposed. The formulation of the generic methodology presented in this paper depends on three simulation models;As-Planned Model (APM,As-Built Model (ABM, and What-Would-HaveBeenModel(WWHBM. The proposed generic methodology as presented in this paper provides a good basis as a more elaborate approach to better analyze claims and their impacts on project time and productivity utilizing discrete event simulation.The approach proposed allows for scenario analysis to account for the disputed events and workflow disruptions. The proposed models will assist claimants in presenting their cases effectively and professionally.

  17. Spacecraft Thermal Management

    Science.gov (United States)

    Hurlbert, Kathryn Miller

    2009-01-01

    In the 21st century, the National Aeronautics and Space Administration (NASA), the Russian Federal Space Agency, the National Space Agency of Ukraine, the China National Space Administration, and many other organizations representing spacefaring nations shall continue or newly implement robust space programs. Additionally, business corporations are pursuing commercialization of space for enabling space tourism and capital business ventures. Future space missions are likely to include orbiting satellites, orbiting platforms, space stations, interplanetary vehicles, planetary surface missions, and planetary research probes. Many of these missions will include humans to conduct research for scientific and terrestrial benefits and for space tourism, and this century will therefore establish a permanent human presence beyond Earth s confines. Other missions will not include humans, but will be autonomous (e.g., satellites, robotic exploration), and will also serve to support the goals of exploring space and providing benefits to Earth s populace. This section focuses on thermal management systems for human space exploration, although the guiding principles can be applied to unmanned space vehicles as well. All spacecraft require a thermal management system to maintain a tolerable thermal environment for the spacecraft crew and/or equipment. The requirements for human rating and the specified controlled temperature range (approximately 275 K - 310 K) for crewed spacecraft are unique, and key design criteria stem from overall vehicle and operational/programatic considerations. These criteria include high reliability, low mass, minimal power requirements, low development and operational costs, and high confidence for mission success and safety. This section describes the four major subsystems for crewed spacecraft thermal management systems, and design considerations for each. Additionally, some examples of specialized or advanced thermal system technologies are presented

  18. Formation of the high-energy ion population in the earth's magnetotail: spacecraft observations and theoretical models

    Directory of Open Access Journals (Sweden)

    A. V. Artemyev

    2014-10-01

    Full Text Available We investigate the formation of the high-energy (E ∈ [20,600] keV ion population in the earth's magnetotail. We collect statistics of 4 years of Interball / Tail observations (1995–1998 in the vicinity of the neutral plane in the magnetotail region (X RE, |Y| ≤ 20 RE in geocentric solar magnetospheric (GSM system. We study the dependence of high-energy ion spectra on the thermal-plasma parameters (the temperature Ti and the amplitude of bulk velocity vi and on the magnetic-field component Bz. The ion population in the energy range E ∈ [20,600] keV can be separated in the thermal core and the power-law tail with the slope (index ~ −4.5. Fluxes of the high-energy ion population increase with the growth of Bz, vi and especially Ti, but spectrum index seems to be independent on these parameters. We have suggested that the high-energy ion population is generated by small scale transient processes, rather than by the global reconfiguration of the magnetotail. We have proposed the relatively simple and general model of ion acceleration by transient bursts of the electric field. This model describes the power-law energy spectra and predicts typical energies of accelerated ions.

  19. Addressing EO-1 Spacecraft Pulsed Plasma Thruster EMI Concerns

    Science.gov (United States)

    Zakrzwski, C. M.; Davis, Mitch; Sarmiento, Charles; Bauer, Frank H. (Technical Monitor)

    2001-01-01

    The Pulsed Plasma Thruster (PPT) Experiment on the Earth Observing One (EO-1) spacecraft has been designed to demonstrate the capability of a new generation PPT to perform spacecraft attitude control. Results from PPT unit level radiated electromagnetic interference (EMI) tests led to concerns about potential interference problems with other spacecraft subsystems. Initial plans to address these concerns included firing the PPT at the spacecraft level both in atmosphere, with special ground support equipment. and in vacuum. During the spacecraft level tests, additional concerns where raised about potential harm to the Advanced Land Imager (ALI). The inadequacy of standard radiated emission test protocol to address pulsed electromagnetic discharges and the lack of resources required to perform compatibility tests between the PPT and an ALI test unit led to changes in the spacecraft level validation plan. An EMI shield box for the PPT was constructed and validated for spacecraft level ambient testing. Spacecraft level vacuum tests of the PPT were deleted. Implementation of the shield box allowed for successful spacecraft level testing of the PPT while eliminating any risk to the ALI. The ALI demonstration will precede the PPT demonstration to eliminate any possible risk of damage of ALI from PPT operation.

  20. A Bibliometric Review on Risk Management and Building Information Modeling for International Construction

    OpenAIRE

    Ganbat, Tsenguun; Chong, Heap-Yih; Liao, Pin-Chao; Wu, You-Di

    2018-01-01

    International construction is complicated and involves high risks. However, with the development of technological innovation, Building Information Modeling (BIM) emerged and seems to be able to address certain risks. To understand BIM applications in risk management for international construction, a state-of-the-art review is required. Therefore, this paper aims to identify the research trends and opportunities for risk management in BIM-enabled international construction by reviewing 526 pee...

  1. Model of the Russian Federation Construction Innovation System: An Integrated Participatory Systems Approach

    OpenAIRE

    Emiliya Suprun; Oz Sahin; Rodney A. Stewart; Kriengsak Panuwatwanich

    2016-01-01

    This research integrates systemic and participatory techniques to model the Russian Federation construction innovation system. Understanding this complex construction innovation system and determining the best levers for enhancing it require the dynamic modelling of a number of factors, such as flows of resources and activities, policies, uncertainty and time. To build the foundations for such a dynamic model, the employed study method utilised an integrated stakeholder-based participatory ap...

  2. Large-Scale Spacecraft Fire Safety Tests

    Science.gov (United States)

    Urban, David; Ruff, Gary A.; Ferkul, Paul V.; Olson, Sandra; Fernandez-Pello, A. Carlos; T'ien, James S.; Torero, Jose L.; Cowlard, Adam J.; Rouvreau, Sebastien; Minster, Olivier; hide

    2014-01-01

    . The first flight (Saffire-1) is scheduled for July 2015 with the other two following at six-month intervals. A computer modeling effort will complement the experimental effort. Although the experiment will need to meet rigorous safety requirements to ensure the carrier vehicle does not sustain damage, the absence of a crew removes the need for strict containment of combustion products. This will facilitate the first examination of fire behavior on a scale that is relevant to spacecraft fire safety and will provide unique data for fire model validation.

  3. Construction of a reliable model pyranometer for irradiance ...

    African Journals Online (AJOL)

    USER

    2010-03-22

    Mar 22, 2010 ... hour, latitude and cloud cover are the most widely or commonly used ... models in the Nigerian environment include that of Burari and Sambo .... influence the stability of the assembly (reducing its phase ... earth's surface.

  4. Construction of classical and quantum integrable field models ...

    Indian Academy of Sciences (India)

    Theory Division, Saha Institute of Nuclear Physics, Kolkata 700 064, India .... above models takes only two different forms: rational or trigonometric ..... parameters c, α, μ, which for different continuum choices for these parameters allows to. 910.

  5. Constructing Business Models around Identity : Tensions in Architectural Firms

    NARCIS (Netherlands)

    Bos-De Vos, M.; Volker, L.; Chan, Paul W; Neilson, Christopher J.

    2017-01-01

    Architectural firms experience difficulties to establish healthy and sustainable business models as they have to reconcile the often-competing value systems that they are based upon. Organizational members continuously negotiate professional values and beliefs with the firm's commercial goals,

  6. Constructing canine carotid artery stenosis model by endovascular technique

    International Nuclear Information System (INIS)

    Cheng Guangsen; Liu Yizhi

    2005-01-01

    Objective: To establish a carotid artery stenosis model by endovascular technique suitable for neuro-interventional therapy. Methods: Twelve dogs were anesthetized, the unilateral segments of the carotid arteries' tunica media and intima were damaged by a corneous guiding wire of home made. Twenty-four carotid artery stenosis models were thus created. DSA examination was performed on postprocedural weeks 2, 4, 8, 10 to estimate the changes of those stenotic carotid arteries. Results: Twenty-four carotid artery stenosis models were successfully created in twelve dogs. Conclusions: Canine carotid artery stenosis models can be created with the endovascular method having variation of pathologic characters and hemodynamic changes similar to human being. It is useful for further research involving the new technique and new material for interventional treatment. (authors)

  7. A geometric construction of traveling waves in a bioremediation model

    NARCIS (Netherlands)

    Beck, M.A.; Doelman, A.; Kaper, T.J.

    2006-01-01

    Bioremediation is a promising technique for cleaning contaminated soil. We study an idealized bioremediation model involving a substrate (contaminant to be removed), electron acceptor (added nutrient), and microorganisms in a one-dimensional soil column. Using geometric singular perturbation theory,

  8. Constructing Molecular Models with Low-Cost Toy Beads

    Science.gov (United States)

    Ng, Pun-hon; Wong, Siu-ling; Mak, Se-yuen

    2012-01-01

    In teaching the science of the nano world, ball-and-stick molecular models are frequently used as 3D representations of molecules. Unlike a chemical formula, a molecular model allows us to visualise the 3D shape of the molecule and the relative positions of its atoms, the bonds between atoms and why a pair of mirror isomers with the same atoms,…

  9. Construction and simulation of a novel continuous traffic flow model

    International Nuclear Information System (INIS)

    Hwang, Yao-Hsin; Yu, Jui-Ling

    2017-01-01

    In this paper, we aim to propose a novel mathematical model for traffic flow and apply a newly developed characteristic particle method to solve the associate governing equations. As compared with the existing non-equilibrium higher-order traffic flow models, the present one is put forward to satisfy the following three conditions: 1.Preserve the equilibrium state in the smooth region. 2.Yield an anisotropic propagation of traffic flow information. 3.Expressed with a conservation law form for traffic momentum. These conditions will ensure a more practical simulation in traffic flow physics: The current traffic will not be influenced by the condition in the behind and result in unambiguous condition across a traffic shock. Through analyses of characteristics, stability condition and steady-state solution adherent to the equation system, it is shown that the proposed model actually conform to these conditions. Furthermore, this model can be cast into its characteristic form which, incorporated with the Rankine-Hugoniot relation, is appropriate to be simulated by the characteristic particle method to obtain accurate computational results. - Highlights: • The traffic model expressed with the momentum conservation law. • Traffic flow information propagate anisotropically and preserve the equilibrium state in the smooth region. • Computational particles of two families are invented to mimic forward-running and backward-running characteristics. • Formation of shocks will be naturally detected by the intersection of computational particles of same family. • A newly developed characteristic particle method is used to simulate traffic flow model equations.

  10. Redundancy for electric motors in spacecraft applications

    Science.gov (United States)

    Smith, Robert J.; Flew, Alastair R.

    1986-01-01

    The parts of electric motors which should be duplicated in order to provide maximum reliability in spacecraft application are identified. Various common types of redundancy are described. The advantages and disadvantages of each are noted. The principal types are illustrated by reference to specific examples. For each example, constructional details, basic performance data and failure modes are described, together with a discussion of the suitability of particular redundancy techniques to motor types.

  11. A Model-Based Approach to Constructing Music Similarity Functions

    Directory of Open Access Journals (Sweden)

    Lamere Paul

    2007-01-01

    Full Text Available Several authors have presented systems that estimate the audio similarity of two pieces of music through the calculation of a distance metric, such as the Euclidean distance, between spectral features calculated from the audio, related to the timbre or pitch of the signal. These features can be augmented with other, temporally or rhythmically based features such as zero-crossing rates, beat histograms, or fluctuation patterns to form a more well-rounded music similarity function. It is our contention that perceptual or cultural labels, such as the genre, style, or emotion of the music, are also very important features in the perception of music. These labels help to define complex regions of similarity within the available feature spaces. We demonstrate a machine-learning-based approach to the construction of a similarity metric, which uses this contextual information to project the calculated features into an intermediate space where a music similarity function that incorporates some of the cultural information may be calculated.

  12. Voxel-based model construction from colored tomographic images

    International Nuclear Information System (INIS)

    Loureiro, Eduardo Cesar de Miranda

    2002-07-01

    This work presents a new approach in the construction of voxel-based phantoms that was implemented to simplify the segmentation process of organs and tissues reducing the time used in this procedure. The segmentation process is performed by painting tomographic images and attributing a different color for each organ or tissue. A voxel-based head and neck phantom was built using this new approach. The way as the data are stored allows an increasing in the performance of the radiation transport code. The program that calculates the radiation transport also works with image files. This capability allows image reconstruction showing isodose areas, under several points of view, increasing the information to the user. Virtual X-ray photographs can also be obtained allowing that studies could be accomplished looking for the radiographic techniques optimization assessing, at the same time, the doses in organs and tissues. The accuracy of the program here presented, called MCvoxEL, that implements this new approach, was tested by comparison to results from two modern and well-supported Monte Carlo codes. Dose conversion factors for parallel X-ray exposure were also calculated. (author)

  13. Model of the Russian Federation Construction Innovation System: An Integrated Participatory Systems Approach

    Directory of Open Access Journals (Sweden)

    Emiliya Suprun

    2016-08-01

    Full Text Available This research integrates systemic and participatory techniques to model the Russian Federation construction innovation system. Understanding this complex construction innovation system and determining the best levers for enhancing it require the dynamic modelling of a number of factors, such as flows of resources and activities, policies, uncertainty and time. To build the foundations for such a dynamic model, the employed study method utilised an integrated stakeholder-based participatory approach coupled with structural analysis (MICMAC—Matrice d'Impacts Croisés Multiplication Appliquée à un Classement Cross-Impact Matrix. This method identified the key factors of the Russian Federation construction innovation system, their causal relationship (i.e., influence/dependence map and, ultimately, a causal loop diagram. The generated model reveals pathways to improving construction innovation in the Russian Federation and underpins the future development of an operationalised system dynamics model.

  14. Applying the Nominal Response Model within a Longitudinal Framework to Construct the Positive Family Relationships Scale

    Science.gov (United States)

    Preston, Kathleen Suzanne Johnson; Parral, Skye N.; Gottfried, Allen W.; Oliver, Pamella H.; Gottfried, Adele Eskeles; Ibrahim, Sirena M.; Delany, Danielle

    2015-01-01

    A psychometric analysis was conducted using the nominal response model under the item response theory framework to construct the Positive Family Relationships scale. Using data from the Fullerton Longitudinal Study, this scale was constructed within a long-term longitudinal framework spanning middle childhood through adolescence. Items tapping…

  15. Ontologies to Support RFID-Based Link between Virtual Models and Construction Components

    DEFF Research Database (Denmark)

    Sørensen, Kristian Birch; Christiansson, Per; Svidt, Kjeld

    2010-01-01

    the virtual models and the physical components in the construction process can improve the information handling and sharing in construction and building operation management. Such a link can be created by means of Radio Frequency Identification (RFID) technology. Ontologies play an important role...

  16. Modelling, Simulation and Construction of a DC/DC Boost Power Converter: A School Experimental System

    Science.gov (United States)

    Silva-Ortigoza, R.; Silva-Ortigoza, G.; Hernandez-Guzman, V. M.; Saldana-Gonzalez, G.; Marcelino-Aranda, M.; Marciano-Melchor, M.

    2012-01-01

    We introduce a dc/dc boost power converter as a didactic prototype intended to support courses on electric circuit analysis experimentally. The corresponding mathematical model is obtained, the converter is designed and an experimental setup is described, constructed and tested. Simplicity of construction as well as low cost of components renders…

  17. RAPS: Robust and Efficient Automatic Construction of Person-Specific Deformable Models

    NARCIS (Netherlands)

    Sagonas, Christos; Panagakis, Yannis; Zafeiriou, Stefanos; Pantic, Maja

    The construction of Facial Deformable Models (FDMs) is a very challenging computer vision problem, since the face is a highly deformable object and its appearance drastically changes under different poses, expressions, and illuminations. Although several methods for generic FDMs construction, have

  18. Modelling, simulation and construction of a dc/dc boost power converter: a school experimental system

    International Nuclear Information System (INIS)

    Silva-Ortigoza, R; Marciano-Melchor, M; Silva-Ortigoza, G; Hernández-Guzmán, V M; Saldaña-González, G; Marcelino-Aranda, M

    2012-01-01

    We introduce a dc/dc boost power converter as a didactic prototype intended to support courses on electric circuit analysis experimentally. The corresponding mathematical model is obtained, the converter is designed and an experimental setup is described, constructed and tested. Simplicity of construction as well as low cost of components renders the feasible introduction of this equipment in undergraduate laboratories. (paper)

  19. Research on information models for the construction schedule management based on the IFC standard

    Directory of Open Access Journals (Sweden)

    Weirui Xue

    2015-05-01

    Full Text Available Purpose: The purpose of this article is to study the description and extension of the Industry Foundation Classes (IFC standard in construction schedule management, which achieves the information exchange and sharing among the different information systems and stakeholders, and facilitates the collaborative construction in the construction projects. Design/methodology/approach: The schedule information processing and coordination are difficult in the complex construction project. Building Information Modeling (BIM provides the platform for exchanging and sharing information among information systems and stakeholders based on the IFC standard. Through analyzing the schedule plan, implementing, check and control, the information flow in the schedule management is reflected based on the IDEF. According to the IFC4, the information model for the schedule management is established, which not only includes the each aspect of the schedule management, but also includes the cost management, the resource management, the quality management and the risk management. Findings: The information requirement for the construction schedule management can be summarized into three aspects: the schedule plan information, the implementing information and the check and control information. The three aspects can be described through the existing and extended entities of IFC4, and the information models are established. Originality/value: The main contribution of the article is to establish the construction schedule management information model, which achieves the information exchange and share in the construction project, and facilitates the development of the application software to meet the requirements of the construction project.

  20. Biomass Scenario Model Scenario Library: Definitions, Construction, and Description

    Energy Technology Data Exchange (ETDEWEB)

    Inman, D.; Vimmerstedt, L.; Bush, B.; Peterson, S.

    2014-04-01

    Understanding the development of the biofuels industry in the United States is important to policymakers and industry. The Biomass Scenario Model (BSM) is a system dynamics model of the biomass-to-biofuels system that can be used to explore policy effects on biofuels development. Because of the complexity of the model, as well as the wide range of possible future conditions that affect biofuels industry development, we have not developed a single reference case but instead developed a set of specific scenarios that provide various contexts for our analyses. The purpose of this report is to describe the scenarios that comprise the BSM scenario library. At present, we have the following policy-focused scenarios in our library: minimal policies, ethanol-focused policies, equal access to policies, output-focused policies, technological diversity focused, and the point-of-production- focused. This report describes each scenario, its policy settings, and general insights gained through use of the scenarios in analytic studies.

  1. The construction and application of didactic models in Biochemistry teaching

    Directory of Open Access Journals (Sweden)

    Maximiliano de Souza Zierer

    2017-10-01

    Full Text Available This work describes how to build and use didactic models as a teaching resource to a more creative teaching in Biochemistry. Students are organized into groups to discuss the creation, planning and execution of models. Previously, the teacher guides the use of various materials for preparation and encourages the use of low cost materials. The day of the activity, held in the classroom, students build their models and are evaluated orally by the teacher about the functions or processes represented. At the end of class, we propose the presentation by each group, plus a general discussion about them. We find that that this methodology makes the classroom an environment highly conducive to creative expression, allowing students to develop their potential and making them effective learning, meaningful and longer lasting when compared to traditional teaching methods.

  2. Construction of Site Risk Model using Individual Unit Risk Model in a NPP Site

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Ho Gon; Han, Sang Hoon [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    Since Fukushima accident, strong needs to estimate site risk has been increased to identify the possibility of re-occurrence of such a tremendous disaster and prevent such a disaster. Especially, in a site which has large fleet of nuclear power plants, reliable site risk assessment is very emergent to confirm the safety. In Korea, there are several nuclear power plant site which have more than 6 NPPs. In general, risk model of a NPP in terms of PSA is very complicated and furthermore, it is expected that the site risk model is more complex than that. In this paper, the method for constructing site risk model is proposed by using individual unit risk model. Procedure for the development of site damage (risk) model was proposed in the present paper. Since the site damage model is complicated in the sense of the scale of the system and dependency of the components of the system, conventional method may not be applicable in many side of the problem.

  3. Construction of radiation - induced metastasis model in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Kuk; Jang, Su Jin; Kang, Sung Wook; Kim, Jae Sung; Hwang, Sang Gu; Kang, Joo Hyun [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2011-05-15

    In treatment of cancer, distant metastases are important limiting factor because an estimated 50% of all cancer patients will develop metastases, and the metastases are major causing of cancer treatment failure. Recently a few reports indicated {gamma}-radiation induced an increase of invasiveness of several cancer cells. In this study, we had tried to show the possibility that radiation could also induce metastasis in vivo system. To prove our hypothesis, we constructed primary tumor by using C6-TL transfectant cell line expressing HSV1-tk and firefly luciferase (fLuc), and then {gamma}-radiation was treated to xenografts locally. Treatment of {gamma}-radiation to primary C6-TL xenografts of mice reduced size of xenografts and elongated survival of mice than those of mock control mice. But we also show that {gamma}-radiation treatment was followed by the growth of dormant metastases in various organs including lung and intestine after 2-4 weeks of {gamma}-radiation treatment. When bioluminescence imaging indicated growth of tumor in organs in mice, we sacrificed the mice and repeat acquired bioluminescence imaging after repeatedly. These images presented tumor growth locations exactly in organs. Because metastatic tumor candidates have morphology of foci, biopsies were performed for histological analysis or PCR analysis to confirm metastases. In most foci, histological analysis indicated several features of typical cancer tissue and PCR analysis showed present of fLuc gene in metastases. Detection of fLuc gene in metastases indicated these foci were originated from primary C6-TL xenografts, and the results suggest that {gamma}-radiation could promote metastasis in vivo as well as in vitro system. Although we need to understand changes of intracellular signaling or physiological phenomena of the radiation-induced metastasis yet, these results also imply that {gamma}-radiation treatment only to cancer patients need to pay attention carefully, and development of new

  4. Construction and Updating of Event Models in Auditory Event Processing

    Science.gov (United States)

    Huff, Markus; Maurer, Annika E.; Brich, Irina; Pagenkopf, Anne; Wickelmaier, Florian; Papenmeier, Frank

    2018-01-01

    Humans segment the continuous stream of sensory information into distinct events at points of change. Between 2 events, humans perceive an event boundary. Present theories propose changes in the sensory information to trigger updating processes of the present event model. Increased encoding effort finally leads to a memory benefit at event…

  5. Constructive Lower Bounds on Model Complexity of Shallow Perceptron Networks

    Czech Academy of Sciences Publication Activity Database

    Kůrková, Věra

    2018-01-01

    Roč. 29, č. 7 (2018), s. 305-315 ISSN 0941-0643 R&D Projects: GA ČR GA15-18108S Institutional support: RVO:67985807 Keywords : shallow and deep networks * model complexity and sparsity * signum perceptron networks * finite mappings * variational norms * Hadamard matrices Subject RIV: IN - Informatics, Computer Science Impact factor: 2.505, year: 2016

  6. Aligning building information model tools and construction management methods

    NARCIS (Netherlands)

    Hartmann, Timo; van Meerveld, H.J.; Vossebeld, N.; Adriaanse, Adriaan Maria

    2012-01-01

    Few empirical studies exist that can explain how different Building Information Model (BIM) based tool implementation strategies work in practical contexts. To help overcoming this gap, this paper describes the implementation of two BIM based tools, the first, to support the activities at an

  7. 3D engineered models for highway construction : the Iowa experience.

    Science.gov (United States)

    2015-06-01

    3D engineered modeling is a relatively new and developing technology that can provide numerous bene ts to owners, engineers, : contractors, and the general public. This manual is for highway agencies that are considering or are in the process of s...

  8. Constructing Self-Modeling Videos: Procedures and Technology

    Science.gov (United States)

    Collier-Meek, Melissa A.; Fallon, Lindsay M.; Johnson, Austin H.; Sanetti, Lisa M. H.; Delcampo, Marisa A.

    2012-01-01

    Although widely recommended, evidence-based interventions are not regularly utilized by school practitioners. Video self-modeling is an effective and efficient evidence-based intervention for a variety of student problem behaviors. However, like many other evidence-based interventions, it is not frequently used in schools. As video creation…

  9. Constructive Models of Discrete and Continuous Physical Phenomena

    Science.gov (United States)

    2014-02-08

    BOURKE , T., CAILLAUD, B., AND POUZET, M. The fundamentals of hybrid systems modelers. Journal of Computer and System Sciences 78, 3 (2012), 877–910...8. BENVENISTE, A., BOURKE , T., CAILLAUD, B., AND POUZET, M. Index theory for hy- brid DAE systems (abstract and slides). In Synchronous Programming

  10. Robust Spacecraft Component Detection in Point Clouds

    Directory of Open Access Journals (Sweden)

    Quanmao Wei

    2018-03-01

    Full Text Available Automatic component detection of spacecraft can assist in on-orbit operation and space situational awareness. Spacecraft are generally composed of solar panels and cuboidal or cylindrical modules. These components can be simply represented by geometric primitives like plane, cuboid and cylinder. Based on this prior, we propose a robust automatic detection scheme to automatically detect such basic components of spacecraft in three-dimensional (3D point clouds. In the proposed scheme, cylinders are first detected in the iteration of the energy-based geometric model fitting and cylinder parameter estimation. Then, planes are detected by Hough transform and further described as bounded patches with their minimum bounding rectangles. Finally, the cuboids are detected with pair-wise geometry relations from the detected patches. After successive detection of cylinders, planar patches and cuboids, a mid-level geometry representation of the spacecraft can be delivered. We tested the proposed component detection scheme on spacecraft 3D point clouds synthesized by computer-aided design (CAD models and those recovered by image-based reconstruction, respectively. Experimental results illustrate that the proposed scheme can detect the basic geometric components effectively and has fine robustness against noise and point distribution density.

  11. Robust Spacecraft Component Detection in Point Clouds.

    Science.gov (United States)

    Wei, Quanmao; Jiang, Zhiguo; Zhang, Haopeng

    2018-03-21

    Automatic component detection of spacecraft can assist in on-orbit operation and space situational awareness. Spacecraft are generally composed of solar panels and cuboidal or cylindrical modules. These components can be simply represented by geometric primitives like plane, cuboid and cylinder. Based on this prior, we propose a robust automatic detection scheme to automatically detect such basic components of spacecraft in three-dimensional (3D) point clouds. In the proposed scheme, cylinders are first detected in the iteration of the energy-based geometric model fitting and cylinder parameter estimation. Then, planes are detected by Hough transform and further described as bounded patches with their minimum bounding rectangles. Finally, the cuboids are detected with pair-wise geometry relations from the detected patches. After successive detection of cylinders, planar patches and cuboids, a mid-level geometry representation of the spacecraft can be delivered. We tested the proposed component detection scheme on spacecraft 3D point clouds synthesized by computer-aided design (CAD) models and those recovered by image-based reconstruction, respectively. Experimental results illustrate that the proposed scheme can detect the basic geometric components effectively and has fine robustness against noise and point distribution density.

  12. A multi-agent safety response model in the construction industry.

    Science.gov (United States)

    Meliá, José L

    2015-01-01

    The construction industry is one of the sectors with the highest accident rates and the most serious accidents. A multi-agent safety response approach allows a useful diagnostic tool in order to understand factors affecting risk and accidents. The special features of the construction sector can influence the relationships among safety responses along the model of safety influences. The purpose of this paper is to test a model explaining risk and work-related accidents in the construction industry as a result of the safety responses of the organization, the supervisors, the co-workers and the worker. 374 construction employees belonging to 64 small Spanish construction companies working for two main companies participated in the study. Safety responses were measured using a 45-item Likert-type questionnaire. The structure of the measure was analyzed using factor analysis and the model of effects was tested using a structural equation model. Factor analysis clearly identifies the multi-agent safety dimensions hypothesized. The proposed safety response model of work-related accidents, involving construction specific results, showed a good fit. The multi-agent safety response approach to safety climate is a useful framework for the assessment of organizational and behavioral risks in construction.

  13. Evolutionary Game Model Study of Construction Green Supply Chain Management under the Government Intervention

    Science.gov (United States)

    Xing, Yuanzhi; Deng, Xiaoyi

    2017-11-01

    The paper first has defined the concepts of green supply chain management and evolution game theory, and pointed out the characteristics of green supply chain management in construction. The main participants and key links of the construction green supply chain management are determined by constructing the organization framework. This paper established the evolutionary game model between construction enterprises and recycling enterprises for the green supply chain closed-loop structure. The waste recycling evolutionary stability equilibrium solution is obtained to explore the principle and effective scope of government policy intervention. This paper put forward the relevant countermeasures to the green supply chain management in construction recycling stage from the government point of view. The conclusion has reference value and guidance to the final product construction enterprises, recycling enterprises and the government during green supply chain.

  14. A Theoretical Model for Meaning Construction through Constructivist Concept Learning

    DEFF Research Database (Denmark)

    Badie, Farshad

    The central focus of this Ph.D. research is on ‘Logic and Cognition’ and, more specifically, this research covers the quintuple (Logic and Logical Philosophy, Philosophy of Education, Educational Psychology, Cognitive Science, Computer Science). The most significant contributions of this Ph.D. di...... of ‘learning’, ‘mentoring’, and ‘knowledge’ within learning and knowledge acquisition systems. Constructivism as an epistemology and as a model of knowing and, respectively as a theoretical model of learning builds up the central framework of this research........D. dissertation are conceptual, logical, terminological, and semantic analysis of Constructivist Concept Learning (specifically, in the context of humans’ interactions with their environment and with other agents). This dissertation is concerned with the specification of the conceptualisation of the phenomena...

  15. A QUADTREE ORGANIZATION CONSTRUCTION AND SCHEDULING METHOD FOR URBAN 3D MODEL BASED ON WEIGHT

    OpenAIRE

    C. Yao; G. Peng; Y. Song; M. Duan

    2017-01-01

    The increasement of Urban 3D model precision and data quantity puts forward higher requirements for real-time rendering of digital city model. Improving the organization, management and scheduling of 3D model data in 3D digital city can improve the rendering effect and efficiency. This paper takes the complexity of urban models into account, proposes a Quadtree construction and scheduling rendering method for Urban 3D model based on weight. Divide Urban 3D model into different rendering weigh...

  16. Constructing a justice model based on Sen's capability approach

    OpenAIRE

    Yüksel, Sevgi; Yuksel, Sevgi

    2008-01-01

    The thesis provides a possible justice model based on Sen's capability approach. For this goal, we first analyze the general structure of a theory of justice, identifying the main variables and issues. Furthermore, based on Sen (2006) and Kolm (1998), we look at 'transcendental' and 'comparative' approaches to justice and concentrate on the sufficiency condition for the comparative approach. Then, taking Rawls' theory of justice as a starting point, we present how Sen's capability approach em...

  17. Topology Optimization of Spacecraft Transfer Compartment

    Directory of Open Access Journals (Sweden)

    A. A. Borovikov

    2016-01-01

    Full Text Available IntroductionThe subject of this research is topology optimization of the adapter of a spacecraft transfer compartment. The finite element topology optimization [1] is widely used for simple structure elements [6, 7]. It is argued that using this method in conjunction with additive technology (3D - printing it is possible to create construction designs with the best weight characteristics. However, the paper shows that when applying this method to a complex construction design the optimization results are highly sensitive to optimization algorithm parameters. The goal of this research is to study parameters of the topology optimization algorithm and the influence of their variations on results.1.      Problem formulation   A commercial software Altair HyperWorks/OptiStruct (student’s license performed numerical calculations. The paper presents a detailed description of the finite element model.The main features of the proposed model are as follows:-          Simplicity with non-complicated geometry;-          Building a finite element model in terms of computing time minimization;-          Using the lumped mass elements to simulate the impacts of the conjugates on the adapter;-          A limit of material strength, decreased by an order of magnitude, to eliminate stress concentrators;-          The gravitational load applied corresponds to the loads for the Angara-A5 launcher [8]. 2.      Method of solutionA brief description of the SIMP-method realized in the Altair HyperWorks/OptiStruct software is given.3.      ResultsPerformed numerical calculations, and shown the influence of variations of algorithm parameters (DISCRETE, MATINIT, MINDIM, MAXDIM on construction design as well as the parameters SINGLE and SPLIT used to reveal restrictions on manufacturing.Shown that, depending on variations of parameters, an adapter construction strives to «truss» or «shell» type. Described

  18. Construction of a Cyber Attack Model for Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Varuttamaseni, Athi; Bari, Robert A.; Youngblood, Robert

    2017-05-01

    The consideration of how one compromised digital equipment can impact neighboring equipment is critical to understanding the progression of cyber attacks. The degree of influence that one component may have on another depends on a variety of factors, including the sharing of resources such as network bandwidth or processing power, the level of trust between components, and the inclusion of segmentation devices such as firewalls. The interactions among components via mechanisms that are unique to the digital world are not usually considered in traditional PRA. This means potential sequences of events that may occur during an attack may be missed if one were to only look at conventional accident sequences. This paper presents a method where, starting from the initial attack vector, the progression of a cyber attack can be modeled. The propagation of the attack is modeled by considering certain attributes of the digital components in the system. These attributes determine the potential vulnerability of a component to a class of attack and the capability gained by the attackers once they are in control of the equipment. The use of attributes allows similar components (components with the same set of attributes) to be modeled in the same way, thereby reducing the computing resources required for analysis of large systems.

  19. Constructing an integrated model of the antecedents of adolescent smoking.

    Science.gov (United States)

    Wilkinson, Dawn; Abraham, Charles

    2004-09-01

    Reviews have called for integrative, theoretically informed models of the 'hundreds of associations' (Miller & Slap, 1989, p. 131) between psychosocial measures and adolescent smoking (e. g. Tyas & Pederson, 1998). Such a model was tested. A prospective, classroom-based survey measuring previously identified correlates of smoking allowed comparison of the strength of relationships between antecedents and smoking status six months later. The prospective sample included 225 13 to 14-year-olds. Measures of behaviour-specific cognitions derived from the Theory of Planned Behaviour (TPB)-as well as personality, self-esteem, parental support and parental control, sociodemographic factors, and descriptive norms-were included. Relationships between antecedents were explored using path analyses. High initial rates of smoking were observed. Of the variance in smoking six months later, 56% was explained by seven direct predictors: intention, perceived ease of smoking, estimated number of friends smoking, percentage of older brothers smoking, self-esteem, extraversion and car access. Results emphasize the importance of behaviour-specific cognitions specified by the TPB but suggest that other factors, including extraversion and self-esteem, need to be included in models of the antecedents of smoking. The findings also imply that some antecedents, such as parental support, may indirectly influence adolescent smoking through their effect on other variables.

  20. Projects Delay Factors of Saudi Arabia Construction Industry Using PLS-SEM Path Modelling Approach

    Directory of Open Access Journals (Sweden)

    Abdul Rahman Ismail

    2016-01-01

    Full Text Available This paper presents the development of PLS-SEM Path Model of delay factors of Saudi Arabia construction industry focussing on Mecca City. The model was developed and assessed using SmartPLS v3.0 software and it consists of 37 factors/manifests in 7 groups/independent variables and one dependent variable which is delay of the construction projects. The model was rigorously assessed at measurement and structural components and the outcomes found that the model has achieved the required threshold values. At structural level of the model, among the seven groups, the client and consultant group has the highest impact on construction delay with path coefficient β-value of 0.452 and the project management and contract administration group is having the least impact to the construction delay with β-value of 0.016. The overall model has moderate explaining power ability with R2 value of 0.197 for Saudi Arabia construction industry representation. This model will able to assist practitioners in Mecca city to pay more attention in risk analysis for potential construction delay.

  1. Decision support model for selecting and evaluating suppliers in the construction industry

    Directory of Open Access Journals (Sweden)

    Fernando Schramm

    2012-12-01

    Full Text Available A structured evaluation of the construction industry's suppliers, considering aspects which make their quality and credibility evident, can be a strategic tool to manage this specific supply chain. This study proposes a multi-criteria decision model for suppliers' selection from the construction industry, as well as an efficient evaluation procedure for the selected suppliers. The model is based on SMARTER (Simple Multi-Attribute Rating Technique Exploiting Ranking method and its main contribution is a new approach to structure the process of suppliers' selection, establishing explicit strategic policies on which the company management system relied to make the suppliers selection. This model was applied to a Civil Construction Company in Brazil and the main results demonstrate the efficiency of the proposed model. This study allowed the development of an approach to Construction Industry which was able to provide a better relationship among its managers, suppliers and partners.

  2. Development and implementation of the South African construction excellence model (SACEM)

    CSIR Research Space (South Africa)

    Dlungwana, WS

    2002-04-01

    Full Text Available The focus of the paper i on the current progress of a research project of the Council for Scientific and Industrial Research's (CSIR) Division of Building and Construction Technology in developing a performance assessment model for contractors...

  3. Waste generated in high-rise buildings construction: a quantification model based on statistical multiple regression.

    Science.gov (United States)

    Parisi Kern, Andrea; Ferreira Dias, Michele; Piva Kulakowski, Marlova; Paulo Gomes, Luciana

    2015-05-01

    Reducing construction waste is becoming a key environmental issue in the construction industry. The quantification of waste generation rates in the construction sector is an invaluable management tool in supporting mitigation actions. However, the quantification of waste can be a difficult process because of the specific characteristics and the wide range of materials used in different construction projects. Large variations are observed in the methods used to predict the amount of waste generated because of the range of variables involved in construction processes and the different contexts in which these methods are employed. This paper proposes a statistical model to determine the amount of waste generated in the construction of high-rise buildings by assessing the influence of design process and production system, often mentioned as the major culprits behind the generation of waste in construction. Multiple regression was used to conduct a case study based on multiple sources of data of eighteen residential buildings. The resulting statistical model produced dependent (i.e. amount of waste generated) and independent variables associated with the design and the production system used. The best regression model obtained from the sample data resulted in an adjusted R(2) value of 0.694, which means that it predicts approximately 69% of the factors involved in the generation of waste in similar constructions. Most independent variables showed a low determination coefficient when assessed in isolation, which emphasizes the importance of assessing their joint influence on the response (dependent) variable. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Take it NP-easy: Bounded model construction for duration calculus

    DEFF Research Database (Denmark)

    Fränzle, Martin

    2002-01-01

    Following the recent successes of bounded model-checking, we reconsider the problem of constructing models of discrete-time Duration Calculus formulae. While this problem is known to be non-elementary when arbitrary length models are considered [Hansen94], it turns out to be only NP-complete when...... constrained to bounded length. As a corollary we obtain that model construction is in NP for the formulae actually encountered in case studies using Duration Calculus, as these have a certain small-model property. First experiments with a prototype implementation of the procedures demonstrate a competitive...

  5. Aircraft, ships, spacecraft, nuclear plants and quality

    International Nuclear Information System (INIS)

    Patrick, M.G.

    1984-05-01

    A few quality assurance programs outside the purview of the Nuclear Regulatory Commission were studied to identify features or practices which the NRC could use to enhance its program for assuring quality in the design and construction of nuclear power plants. The programs selected were: the manufacture of large commercial transport aircraft, regulated by the Federal Aviation Administration; US Navy shipbuilding; commercial shipbuilding regulated by the Maritime Administration and the US Coast Guard; Government-owned nuclear plants under the Department of Energy; spacecraft under the National Aeronautics and Space Administration; and the construction of nuclear power plants in Canada, West Germany, France, Japan, Sweden, and the United Kingdom

  6. About the Big Graphs Arising when Forming the Diagnostic Models in a Reconfigurable Computing Field of Functional Monitoring and Diagnostics System of the Spacecraft Onboard Control Complex

    Directory of Open Access Journals (Sweden)

    L. V. Savkin

    2015-01-01

    Full Text Available One of the problems in implementation of the multipurpose complete systems based on the reconfigurable computing fields (RCF is the problem of optimum redistribution of logicalarithmetic resources in growing scope of functional tasks. Irrespective of complexity, all of them are transformed into an orgraph, which functional and topological structure is appropriately imposed on the RCF based, as a rule, on the field programmable gate array (FPGA.Due to limitation of the hardware configurations and functions realized by means of the switched logical blocks (SLB, the abovementioned problem becomes even more critical when there is a need, within the strictly allocated RCF fragment, to realize even more complex challenge in comparison with the problem which was solved during the previous computing step. In such cases it is possible to speak about graphs of big dimensions with respect to allocated RCF fragment.The article considers this problem through development of diagnostic algorithms to implement diagnostics and control of an onboard control complex of the spacecraft using RCF. It gives examples of big graphs arising with respect to allocated RCF fragment when forming the hardware levels of a diagnostic model, which, in this case, is any hardware-based algorithm of diagnostics in RCF.The article reviews examples of arising big graphs when forming the complicated diagnostic models due to drastic difference in formation of hardware levels on closely located RCF fragments. It also pays attention to big graphs emerging when the multichannel diagnostic models are formed.Three main ways to solve the problem of big graphs with respect to allocated RCF fragment are given. These are: splitting the graph into fragments, use of pop-up windows with relocating and memorizing intermediate values of functions of high hardware levels of diagnostic models, and deep adaptive update of diagnostic model.It is shown that the last of three ways is the most efficient

  7. Evaluation on the efficiency of the construction sector companies in Malaysia with data envelopment analysis model

    Science.gov (United States)

    Weng Hoe, Lam; Jinn, Lim Shun; Weng Siew, Lam; Hai, Tey Kim

    2018-04-01

    In Malaysia, construction sector is essential parts in driving the development of the Malaysian economy. Construction industry is an economic investment and its relationship with economic development is well posited. However, the evaluation on the efficiency of the construction sectors companies listed in Kuala Lumpur Stock Exchange (KLSE) with Data Analysis Envelopment (DEA) model have not been actively studied by the past researchers. Hence the purpose of this study is to examine the financial performance the listed construction sectors companies in Malaysia in the year of 2015. The results of this study show that the efficiency of construction sectors companies can be obtained by using DEA model through ratio analysis which defined as the ratio of total outputs to total inputs. This study is significant because the inefficient companies are identified for potential improvement.

  8. Challenges of the expansive use of Building Information Modeling (BIM in construction projects

    Directory of Open Access Journals (Sweden)

    Hannele Kerosuo

    2015-06-01

    Full Text Available Building information modeling (BIM is an emerging modeling technology which challenges existing work procedures and practices in the construction industry. In this article we study the challenges, problems and potential expansions of BIM as a tool in the design, construction and operation of buildings. For this purpose the interfaces between different parties are examined in Finnish construction projects. The methodological approach of the study is cultural-historical activity theory, according to which a new artifact becomes a mediating instrument when the participatory subjects reconfigure the entire activity. The implementation of BIM is now spreading from the design activity to other phases of the construction projects, but its use is still limited in the projects' other three interfaces. BIM is an evolving set of software developed for various purposes which is locally 'combined' to fit the circumstances and capabilities of the stakeholders of the construction process.

  9. Spacecraft exploration of asteroids

    International Nuclear Information System (INIS)

    Veverka, J.; Langevin, Y.; Farquhar, R.; Fulchignoni, M.

    1989-01-01

    After two decades of spacecraft exploration, we still await the first direct investigation of an asteroid. This paper describes how a growing international interest in the solar system's more primitive bodies should remedy this. Plans are under way in Europe for a dedicated asteroid mission (Vesta) which will include multiple flybys with in situ penetrator studies. Possible targets include 4 Vesta, 8 Flora and 46 Hestia; launch its scheduled for 1994 or 1996. In the United States, NASA plans include flybys of asteroids en route to outer solar system targets

  10. Spacecraft rendezvous and docking

    DEFF Research Database (Denmark)

    Jørgensen, John Leif

    1999-01-01

    The phenomenons and problems encountered when a rendezvous manoeuvre, and possible docking, of two spacecrafts has to be performed, have been the topic for numerous studies, and, details of a variety of scenarios has been analysed. So far, all solutions that has been brought into realization has...... been based entirely on direct human supervision and control. This paper describes a vision-based system and methodology, that autonomously generates accurate guidance information that may assist a human operator in performing the tasks associated with both the rendezvous and docking navigation...

  11. Constructing warm inflationary model in brane–antibrane system

    Energy Technology Data Exchange (ETDEWEB)

    Setare, M.R., E-mail: rezakord@ipm.ir [Department of Science, Campus of Bijar, University of Kurdistan, Bijar (Iran, Islamic Republic of); Sepehri, A., E-mail: alireza.sepehri@uk.ac.ir [Faculty of Physics, Shahid Bahonar University, P.O. Box 76175, Kerman (Iran, Islamic Republic of); Kamali, V., E-mail: Vkamali@basu.ac.ir [Department of Physics, Faculty of Science, Bu-Ali Sina University, Hamedan, 65178 (Iran, Islamic Republic of)

    2014-07-30

    Recently, various observational data predicted a possibility that inflation may naturally occur in a warm region. In this scenario, radiation is produced during the inflation epoch and reheating is avoided. The main question arises as to what is the origin of warm inflation in 4D universe? We answer this question in brane–antibrane system. We propose a model that allows all cosmological parameters like the scale factor a, the Hubble parameter H and phantom energy density depend on the equation of state parameter in transverse dimension between two branes. Thus, an enhancement in these parameters can be a signature of some evolutions in extra dimension. In our model, the expansion of 4D universe is controlled by the separation distance between branes and evolves from non-phantom phase to phantom one. Consequently, phantom-dominated era of the universe accelerates and ends up in big-rip singularity. Also, we show that as the tachyon potential increases, the effect of interaction between branes on the 4D universe expansion becomes systematically more effective, because at higher energies there exist more channels for flowing energy from extra dimension to other four dimensions. Finally, we test our model against WMAP and Planck data and obtain the ripping time. According to experimental data, N≃50 case leads to n{sub s}≃0.96, where N and n{sub s} are the number e-folds and the spectral index respectively. This standard case may be found in 0.01

  12. Construction and updating of event models in auditory event processing.

    Science.gov (United States)

    Huff, Markus; Maurer, Annika E; Brich, Irina; Pagenkopf, Anne; Wickelmaier, Florian; Papenmeier, Frank

    2018-02-01

    Humans segment the continuous stream of sensory information into distinct events at points of change. Between 2 events, humans perceive an event boundary. Present theories propose changes in the sensory information to trigger updating processes of the present event model. Increased encoding effort finally leads to a memory benefit at event boundaries. Evidence from reading time studies (increased reading times with increasing amount of change) suggest that updating of event models is incremental. We present results from 5 experiments that studied event processing (including memory formation processes and reading times) using an audio drama as well as a transcript thereof as stimulus material. Experiments 1a and 1b replicated the event boundary advantage effect for memory. In contrast to recent evidence from studies using visual stimulus material, Experiments 2a and 2b found no support for incremental updating with normally sighted and blind participants for recognition memory. In Experiment 3, we replicated Experiment 2a using a written transcript of the audio drama as stimulus material, allowing us to disentangle encoding and retrieval processes. Our results indicate incremental updating processes at encoding (as measured with reading times). At the same time, we again found recognition performance to be unaffected by the amount of change. We discuss these findings in light of current event cognition theories. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  13. The constructive backlash dissipate effect model for concrete blocks

    International Nuclear Information System (INIS)

    Tepes-Onea Florin

    2004-01-01

    From physical point of view, the dumping represents the soil seismic excitation energy taken over process through internal absorption, rubbed between existent layers, as and cracks on rocky foundations. Generally, on heavy dams dynamic analysis it is considered a viscous dump, proportional with deformation speed. The dumping can be evaluated on experimental bases or on environmental conditions measurements. The latest determine higher values of dumping elements. This it could be explained with the local factors influence which is not possible to modeled as backlash treatment, foundation ground characteristics, the concrete technology. This represents atypical dissipate phenomenon. A major influence is done by the excitation level as real seism or experimental excitation. The present work is about to establish the influence of the dissipate effect of the backlash on concrete blocks. The backlash finite elements modeling make this possible, studying different situations as rub effect, cohesion effect, seismic action on varying directions with the same accelerogram of 0.4 g. The studied blocks have the same dimensions, the relative displacement being obtained by foundation stiffness modified under two block parts. (author)

  14. Network design and operational modelling for construction green supply chain management

    Directory of Open Access Journals (Sweden)

    Pengfei Zhou Dong Chen

    2013-01-01

    Full Text Available Based on studying organizational structure of Construction Green Supply Chain Management (CGSCM, a mathematical programming model of CGSCM was proposed. The model aimed to maximize the aggregate profits of normalized construction logistics, the reverse logistics and the environmental performance. Numerical experiments show that the proposed approach can improve the aggregate profit effectively. In addition, return ratio, subsidies from governmental organizations, and environmental performance were analyzed for CGSCM performance. Herein, the proper return, subsidy and control strategy could optimize construction green supply chain.

  15. Kaluza-Klein models: Can we construct a viable example?

    International Nuclear Information System (INIS)

    Eingorn, Maxim; Zhuk, Alexander

    2011-01-01

    In Kaluza-Klein models with toroidal compactification of the extra dimensions, we investigate soliton solutions of Einstein equation. The nonrelativistic gravitational potential of these solitons exactly coincides with the Newtonian one. We obtain the formulas for perihelion shift, deflection of light, time delay of radar echoes and post-Newtonian (PPN) parameters. Using the constraint on PPN parameter γ, we find that the solitonic parameter k should be very big: |k|≥2.3x10 4 . We define a soliton solution which corresponds to a pointlike mass source. In this case the soliton parameter k=2, which is clearly contrary to this restriction. A similar problem with the observations takes place for static spherically symmetric perfect fluid with the dustlike equation of state in all dimensions. The common for both of these models is the same (dustlike) equations of state in our three dimensions and in the extra dimensions. All dimensions are treated at equal footing. This is the crucial point. To be in agreement with observations, it is necessary to break the symmetry (in terms of equations of state) between the external/our and internal spaces. It takes place for black strings which are particular examples of solitons with k→∞. For such k, black strings are in concordance with the observations. Moreover, we show that they are the only solitons which are at the same level of agreement with the observations as in general relativity. Black strings can be treated as perfect fluid with dustlike equation of state p 0 =0 in the external/our space and very specific equation of state p 1 =-(1/2)ε in the internal space. The latter equation is due to negative tension in the extra dimension. We also demonstrate that dimension 3 for the external space is a special one. Only in this case we get the latter equation of state. We show that the black string equations of state satisfy the necessary condition of the internal space stabilization. Therefore, black strings are good

  16. Modeling Signal-Noise Processes Supports Student Construction of a Hierarchical Image of Sample

    Science.gov (United States)

    Lehrer, Richard

    2017-01-01

    Grade 6 (modal age 11) students invented and revised models of the variability generated as each measured the perimeter of a table in their classroom. To construct models, students represented variability as a linear composite of true measure (signal) and multiple sources of random error. Students revised models by developing sampling…

  17. On the possibility on constructing covariant chromomagnetic field models

    International Nuclear Information System (INIS)

    Cabo, A.; Penaranda, S.; Martinez, R.

    1995-03-01

    Expressions for SO(4) invariant euclidean QCD generating functionals are introduced which should produce non-vanishing gluon condensates. Their investigation is started here by initially considering the loop expansion of the corresponding effective action searching for a description differing from the usual perturbation theory. At this level, we consider special free propagators showing a sort or off-diagonal long range order. The calculation of the polarization tensor leads to a gluon mass term which is proportional to the squared root of the also finite value for 2 >. The summation of all the one-loop contributions to the energy having only mass insertions, indicates the spontaneous generation of the condensate from the perturbative grounds state in a way resembling the similar effect in the case of the chromomagnetic field models. This initial inspection suggests the need for a closer investigation which will be considered elsewhere. (author). 22 refs

  18. Construction of high-quality NN potential models

    International Nuclear Information System (INIS)

    Stoks, V.G.J.; Klomp, R.A.M.; Terheggen, C.P.F.; de Swart, J.J.

    1994-01-01

    We present an updated version (Nijm93) of the Nijmegen soft-core potential, which gives a much better description of the np data than the older version (Nijm78). The χ 2 per datum is 1.87. The configuration-space and momentum-space versions of this potential are exactly equivalent, a unique feature among meson-theoretical potentials. We also present three new NN potential models: a nonlocal Reid-like Nijmegen potential (Nijm I), a local version (Nijm II), and an updated regularized version (Reid 93) of the Reid soft-core potential. These three potentials all have a nearly optimal χ 2 per datum and can therefore be considered as alternative partial-wave analyses. All potentials contain the proper charge-dependent one-pion-exchange tail

  19. Application of Space Environmental Observations to Spacecraft Pre-Launch Engineering and Spacecraft Operations

    Science.gov (United States)

    Barth, Janet L.; Xapsos, Michael

    2008-01-01

    This presentation focuses on the effects of the space environment on spacecraft systems and applying this knowledge to spacecraft pre-launch engineering and operations. Particle radiation, neutral gas particles, ultraviolet and x-rays, as well as micrometeoroids and orbital debris in the space environment have various effects on spacecraft systems, including degradation of microelectronic and optical components, physical damage, orbital decay, biasing of instrument readings, and system shutdowns. Space climate and weather must be considered during the mission life cycle (mission concept, mission planning, systems design, and launch and operations) to minimize and manage risk to both the spacecraft and its systems. A space environment model for use in the mission life cycle is presented.

  20. Towards a Unified Business Model Vocabulary: A Proposition of Key Constructs

    OpenAIRE

    Mettler, Tobias

    2014-01-01

    The design of business models is of decisive importance and as such it has been a major research theme in service and particularly electronic markets. Today, different definitions of the term and ideas of core constructs of business models exist. In this paper we present a unified vocabulary for business models that builds upon the elementary perception of three existing, yet very dissimilar ontologies for modeling the essence of a business. The resulting unified business model vocabulary not...

  1. Calibration models for density borehole logging - construction report

    International Nuclear Information System (INIS)

    Engelmann, R.E.; Lewis, R.E.; Stromswold, D.C.

    1995-10-01

    Two machined blocks of magnesium and aluminum alloys form the basis for Hanford's density models. The blocks provide known densities of 1.780 ± 0.002 g/cm 3 and 2.804 ± 0.002 g/cm 3 for calibrating borehole logging tools that measure density based on gamma-ray scattering from a source in the tool. Each block is approximately 33 x 58 x 91 cm (13 x 23 x 36 in.) with cylindrical grooves cut into the sides of the blocks to hold steel casings of inner diameter 15 cm (6 in.) and 20 cm (8 in.). Spacers that can be inserted between the blocks and casings can create air gaps of thickness 0.64, 1.3, 1.9, and 2.5 cm (0.25, 0.5, 0.75 and 1.0 in.), simulating air gaps that can occur in actual wells from hole enlargements behind the casing

  2. Model construction of “earning money by taking photos”

    Science.gov (United States)

    Yang, Jingmei

    2018-03-01

    In the era of information, with the increasingly developed network, “to earn money by taking photos” is a self-service model under the mobile Internet. The user downloads the APP, registers as a member of the APP, and then takes a task that needs to take photographs from the APP and earns the reward of the task on the APP. The article uses the task data and membership information data of an already completed project, including the member’s location and reputation value. On the basis of reasonable assumption, the data was processed with the MATLAB, SPSS and Excel software. This article mainly studied problems of the function relationship between the task performance, task position (GPS latitude and GPS longitude) and task price of users, analyzed the project’s task pricing rules and the reasons why the task is not completed, and applied multivariate regression function and GeoQ software to analyze the data, studied the task pricing rules, applied the chart method to solve the complex data, clear and easy to understand, and also reality simulation is applied to analyze why the tasks are not completed. Also, compared with the previous program, a new task pricing program is designed for the project to obtain the confidence level by means of the SPSS software, to estimate the reasonable range of the task pricing, predict and design a new pricing program on the reasonable price range.

  3. Automating Trend Analysis for Spacecraft Constellations

    Science.gov (United States)

    Davis, George; Cooter, Miranda; Updike, Clark; Carey, Everett; Mackey, Jennifer; Rykowski, Timothy; Powers, Edward I. (Technical Monitor)

    2001-01-01

    missions such as DRACO with the intent that mission operations costs be significantly reduced. The goal of the Constellation Spacecraft Trend Analysis Toolkit (CSTAT) project is to serve as the pathfinder for a fully automated trending system to support spacecraft constellations. The development approach to be taken is evolutionary. In the first year of the project, the intent is to significantly advance the state of the art in current trending systems through improved functionality and increased automation. In the second year, the intent is to add an expert system shell, likely through the adaptation of an existing commercial-off-the-shelf (COTS) or government-off-the-shelf (GOTS) tool to implement some level of the trending intelligence that humans currently provide in manual operations. In the third year, the intent is to infuse the resulting technology into a near-term constellation or formation-flying mission to test it and gain experience in automated trending. The lessons learned from the real missions operations experience will then be used to improve the system, and to ultimately incorporate it into a fully autonomous, closed-loop mission operations system that is truly capable of supporting large constellations. In this paper, the process of automating trend analysis for spacecraft constellations will be addressed. First, the results of a survey on automation in spacecraft mission operations in general, and in trending systems in particular will be presented to provide an overview of the current state of the art. Next, a rule-based model for implementing intelligent spacecraft subsystem trending will be then presented, followed by a survey of existing COTS/GOTS tools that could be adapted for implementing such a model. The baseline design and architecture of the CSTAT system will be presented. Finally, some results obtained from initial software tests and demonstrations will be presented.

  4. Building information modelling (BIM) after ten years: Malaysian construction players’ perception of BIM

    Science.gov (United States)

    Latiffi, A. Ahmad; Brahim, J.; Fathi, M. S.

    2017-08-01

    Building Information Modelling (BIM) concept has expanded widely in many countries for more than a decade with its role of improving current practices in construction projects. However, the understanding of BIM differs among construction players, depending on how construction players utilize the concept in their projects. Therefore, this paper aims to explore the understanding of BIM concept among construction players in the Malaysian construction industry. A literature review on BIM concept and semi-structured interviews with construction players in BIM such as client, civil and structural (C&S) engineer and mechanical and electrical (M&E) engineer, quantity surveyor (QS), contractor, facilities manager and BIM consultant have been conducted in order to achieve this study’s the aim. The results show that the understanding of BIM concept among the construction players is limited to BIM as a process and technology. It is important for the construction players to improve their understanding of BIM as it can be used to enhance performance and productivity of construction projects.

  5. Design feasibility via ascent optimality for next-generation spacecraft

    Science.gov (United States)

    Miele, A.; Mancuso, S.

    This paper deals with the optimization of the ascent trajectories for single-stage-sub-orbit (SSSO), single-stage-to-orbit (SSTO), and two-stage-to-orbit (TSTO) rocket-powered spacecraft. The maximum payload weight problem is studied for different values of the engine specific impulse and spacecraft structural factor. The main conclusions are that: feasibility of SSSO spacecraft is guaranteed for all the parameter combinations considered; feasibility of SSTO spacecraft depends strongly on the parameter combination chosen; not only feasibility of TSTO spacecraft is guaranteed for all the parameter combinations considered, but the TSTO payload is several times the SSTO payload. Improvements in engine specific impulse and spacecraft structural factor are desirable and crucial for SSTO feasibility; indeed, aerodynamic improvements do not yield significant improvements in payload. For SSSO, SSTO, and TSTO spacecraft, simple engineering approximations are developed connecting the maximum payload weight to the engine specific impulse and spacecraft structural factor. With reference to the specific impulse/structural factor domain, these engineering approximations lead to the construction of zero-payload lines separating the feasibility region (positive payload) from the unfeasibility region (negative payload).

  6. Construction of a digital elevation model: methods and parallelization

    International Nuclear Information System (INIS)

    Mazzoni, Christophe

    1995-01-01

    The aim of this work is to reduce the computation time needed to produce the Digital Elevation Models (DEM) by using a parallel machine. It is made in collaboration between the French 'Institut Geographique National' (IGN) and the Laboratoire d'Electronique de Technologie et d'Instrumentation (LETI) of the French Atomic Energy Commission (CEA). The IGN has developed a system which provides DEM that is used to produce topographic maps. The kernel of this system is the correlator, a software which automatically matches pairs of homologous points of a stereo-pair of photographs. Nevertheless the correlator is expensive In computing time. In order to reduce computation time and to produce the DEM with same accuracy that the actual system, we have parallelized the IGN's correlator on the OPENVISION system. This hardware solution uses a SIMD (Single Instruction Multiple Data) parallel machine SYMPATI-2, developed by the LETI that is involved in parallel architecture and image processing. Our analysis of the implementation has demonstrated the difficulty of efficient coupling between scalar and parallel structure. So we propose solutions to reinforce this coupling. In order to accelerate more the processing we evaluate SYMPHONIE, a SIMD calculator, successor of SYMPATI-2. On an other hand, we developed a multi-agent approach for what a MIMD (Multiple Instruction, Multiple Data) architecture is available. At last, we describe a Multi-SIMD architecture that conciliates our two approaches. This architecture offers a capacity to apprehend efficiently multi-level treatment image. It is flexible by its modularity, and its communication network supplies reliability that interest sensible systems. (author) [fr

  7. IMPROVING TRADITIONAL BUILDING REPAIR CONSTRUCTION QUALITY USING HISTORIC BUILDING INFORMATION MODELING CONCEPT

    Directory of Open Access Journals (Sweden)

    T. C. Wu

    2013-07-01

    Full Text Available In addition to the repair construction project following the repair principles contemplated by heritage experts, the construction process should be recorded and measured at any time for monitoring to ensure the quality of repair. The conventional construction record methods mostly depend on the localized shooting of 2D digital images coupled with text and table for illustration to achieve the purpose of monitoring. Such methods cannot fully and comprehensively record the 3D spatial relationships in the real world. Therefore, the construction records of traditional buildings are very important but cannot function due to technical limitations. This study applied the 3D laser scanning technology to establish a 3D point cloud model for the repair construction of historical buildings. It also broke down the detailed components of the 3D point cloud model by using the concept of the historic building information modeling, and established the 3D models of various components and their attribute data in the 3DGIS platform database. In the construction process, according to the time of completion of each stage as developed on the construction project, this study conducted the 3D laser scanning and database establishment for each stage, also applied 3DGIS spatial information and attribute information comparison and analysis to propose the analysis of differences in completion of various stages for improving the traditional building repair construction quality. This method helps to improve the quality of repair construction work of tangible cultural assets of the world. The established 3DGIS platform can be used as a power tool for subsequent management and maintenance.

  8. Guidance and control of swarms of spacecraft

    Science.gov (United States)

    Morgan, Daniel James

    There has been considerable interest in formation flying spacecraft due to their potential to perform certain tasks at a cheaper cost than monolithic spacecraft. Formation flying enables the use of smaller, cheaper spacecraft that distribute the risk of the mission. Recently, the ideas of formation flying have been extended to spacecraft swarms made up of hundreds to thousands of 100-gram-class spacecraft known as femtosatellites. The large number of spacecraft and limited capabilities of each individual spacecraft present a significant challenge in guidance, navigation, and control. This dissertation deals with the guidance and control algorithms required to enable the flight of spacecraft swarms. The algorithms developed in this dissertation are focused on achieving two main goals: swarm keeping and swarm reconfiguration. The objectives of swarm keeping are to maintain bounded relative distances between spacecraft, prevent collisions between spacecraft, and minimize the propellant used by each spacecraft. Swarm reconfiguration requires the transfer of the swarm to a specific shape. Like with swarm keeping, minimizing the propellant used and preventing collisions are the main objectives. Additionally, the algorithms required for swarm keeping and swarm reconfiguration should be decentralized with respect to communication and computation so that they can be implemented on femtosats, which have limited hardware capabilities. The algorithms developed in this dissertation are concerned with swarms located in low Earth orbit. In these orbits, Earth oblateness and atmospheric drag have a significant effect on the relative motion of the swarm. The complicated dynamic environment of low Earth orbits further complicates the swarm-keeping and swarm-reconfiguration problems. To better develop and test these algorithms, a nonlinear, relative dynamic model with J2 and drag perturbations is developed. This model is used throughout this dissertation to validate the algorithms

  9. Spacecraft Attitude Control in Hamiltonian Framework

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    2000-01-01

    The objective of this paper is to give a design scheme for attitude control algorithms of a generic spacecraft. Along with the system model formulated in the Hamilton's canonical form the algorithm uses information about a required potential energy and a dissipative term. The control action...

  10. Using decomposition kinetics to model the removal of mine water pollutants in constructed wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Tarutis, W J; Unz, R F [Pennsylvania State University, University Park, PA (United States)

    1994-01-01

    Although numerous mathematical models have been used to describe decomposition, few, if any, have been used to model the removal of pollutants in constructed wetlands. A steady state method based on decomposition kinetics and reaction stoichiometry has been developed which simulates the removal of ferrous iron entering wetlands constructed for mine drainage treatment. Input variables for the model include organic matter concentration, reaction rate coefficient, porosity and dry density, and hydraulic detection time. Application of the model assumes complete anaerobic conditions within the entire substrate profile, constant temperature, no additional organic matter input, and subsurface flow only. For these ideal conditions, model simulations indicate that wetlands constructed with readily decomposable substrates rich in organic carbon are initially capable of removing far greater amounts of iron than wetlands built with less biodegradable substrates. However, after three to five years of operation this difference becomes negligible. For acceptable long-term treatment performance, therefore, periodic additions of decomposable organic matter will be required.

  11. Application of 3D CADDS model to design and engineering for constructability improvement

    International Nuclear Information System (INIS)

    Cho, U.Y.; Park, C.C.; Choy, E.

    1998-01-01

    The use of three dimensional (3D) computer-aided design and drafting system (CADDS) model along with the associated information management system in engineering phases of large projects is well established and yielding significant improvements in project cost, schedule and quality. The information contained in these models can also be utilized in plant construction site for construction schedule review, installation procedure review, interference check, and visual communication tool to the utility owner when the visual and spatial information contained in the 3D models is integrated with other plant information. This paper will describe the application of 3D models and the associated databases in the construction process of CANDU HWR heavy water reactors. Some examples on the use of 3D CADD models in CANDU projects will be presented

  12. MULTIAGENT IMITATION MODEL OF A REGIONAL CONSTRUCTION CLUSTER AS A HETERARCHICAL SYSTEM

    Directory of Open Access Journals (Sweden)

    Anufriev Dmitriy Petrovich

    2018-01-01

    Full Text Available Subject: a regional construction cluster, which is viewed as a complex system territorially localized within the region, consisting of interconnected and complementary enterprises of construction and related industries that are united with local institutions, authorities and cooperating enterprises by heterarchic relations. Research objectives: development of multi-agent simulation model that allows us to examine the business-processes in the regional construction cluster as a complex heterarchical system. Materials and methods: we formulate the mathematical problem for description of processes in a heterarchic system as in a special multi-agent queueing network. Conclusions: the article substantiates application of the decentralized approach which is based on the use of agent methodology. Several types of agents that model elementary organizational structures have been developed. We describe the functional core of the multi-agent simulation model characterizing the heterarchic organizational model. Using the Fishman-Kivia criterion, the adequacy of the logical functioning of the developed model was established.

  13. Modeling the factors affecting unsafe behavior in the construction industry from safety supervisors' perspective.

    Science.gov (United States)

    Khosravi, Yahya; Asilian-Mahabadi, Hassan; Hajizadeh, Ebrahim; Hassanzadeh-Rangi, Narmin; Bastani, Hamid; Khavanin, Ali; Mortazavi, Seyed Bagher

    2014-01-01

    There can be little doubt that the construction is the most hazardous industry in the worldwide. This study was designed to modeling the factors affecting unsafe behavior from the perspective of safety supervisors. The qualitative research was conducted to extract a conceptual model. A structural model was then developed based on a questionnaire survey (n=266) by two stage Structural Equation Model (SEM) approach. An excellent confirmed 12-factors structure explained about 62% of variances unsafe behavior in the construction industry. A good fit structural model indicated that safety climate factors were positively correlated with safety individual factors (Pconstruction workers' engagement in safe or unsafe behavior. In order to improve construction safety performance, more focus on the workplace condition is required.

  14. Quantitative Decision Making Model for Carbon Reduction in Road Construction Projects Using Green Technologies

    Directory of Open Access Journals (Sweden)

    Woosik Jang

    2015-08-01

    Full Text Available Numerous countries have established policies for reducing greenhouse gas emissions and have suggested goals pertaining to these reductions. To reach the target reduction amounts, studies on the reduction of carbon emissions have been conducted with regard to all stages and processes in construction projects. According to a study on carbon emissions, the carbon emissions generated during the construction stage of road projects account for approximately 76 to 86% of the total carbon emissions, far exceeding the other stages, such as maintenance or demolition. Therefore, this study aims to develop a quantitative decision making model that supports the application of green technologies (GTs to reduce carbon emissions during the construction stage of road construction projects. First, the authors selected environmental soundness, economic feasibility and constructability as the key assessment indices for evaluating 20 GTs. Second, a fuzzy set/qualitative comparative analysis (FS/QCA was used to establish an objective decision-making model for the assessment of both the quantitative and qualitative characteristics of the key indices. To support the developed model, an expert survey was performed to assess the applicability of each GT from a practical perspective, which was verified with a case study using two additional GTs. The proposed model is expected to support practitioners in the application of suitable GTs to road projects and reduce carbon emissions, resulting in better decision making during road construction projects.

  15. The Structured Process Modeling Method (SPMM) : what is the best way for me to construct a process model?

    NARCIS (Netherlands)

    Claes, J.; Vanderfeesten, I.T.P.; Gailly, F.; Grefen, P.W.P.J.; Poels, G.

    2017-01-01

    More and more organizations turn to the construction of process models to support strategical and operational tasks. At the same time, reports indicate quality issues for a considerable part of these models, caused by modeling errors. Therefore, the research described in this paper investigates the

  16. Construction and Quantification of the One Top model of the Fire Events PSA

    International Nuclear Information System (INIS)

    Kang, Dae Il; Lee, Yoon Hwan; Han, Sang Hoon

    2008-01-01

    KAERI constructed the one top model of the fire events PSA for Ulchin Unit 3 and 4 by using the 'mapping technique'. The mapping technique was developed for the construction and quantification of external events PSA models with a one top model for an internal events PSA. With 'AIMS', the mapping technique can be implemented by the construction of mapping tables. The mapping tables include fire rooms, fire ignition frequency, related initiating events, fire transfer events, and the internal PSA basic events affected by a fire. The constructed one top fire PSA model is based on previously conducted fire PSA results for Ulchin Unit 3 and 4. In this paper, we introduce the construction procedure and quantification results of the one top model of the fire events PSA by using the mapping technique. As the one top model of the fire events PSA developed in this study is based on the previous study, we also introduce the previous fire PSA approach focused on quantification

  17. a Quadtree Organization Construction and Scheduling Method for Urban 3d Model Based on Weight

    Science.gov (United States)

    Yao, C.; Peng, G.; Song, Y.; Duan, M.

    2017-09-01

    The increasement of Urban 3D model precision and data quantity puts forward higher requirements for real-time rendering of digital city model. Improving the organization, management and scheduling of 3D model data in 3D digital city can improve the rendering effect and efficiency. This paper takes the complexity of urban models into account, proposes a Quadtree construction and scheduling rendering method for Urban 3D model based on weight. Divide Urban 3D model into different rendering weights according to certain rules, perform Quadtree construction and schedule rendering according to different rendering weights. Also proposed an algorithm for extracting bounding box extraction based on model drawing primitives to generate LOD model automatically. Using the algorithm proposed in this paper, developed a 3D urban planning&management software, the practice has showed the algorithm is efficient and feasible, the render frame rate of big scene and small scene are both stable at around 25 frames.

  18. A QUADTREE ORGANIZATION CONSTRUCTION AND SCHEDULING METHOD FOR URBAN 3D MODEL BASED ON WEIGHT

    Directory of Open Access Journals (Sweden)

    C. Yao

    2017-09-01

    Full Text Available The increasement of Urban 3D model precision and data quantity puts forward higher requirements for real-time rendering of digital city model. Improving the organization, management and scheduling of 3D model data in 3D digital city can improve the rendering effect and efficiency. This paper takes the complexity of urban models into account, proposes a Quadtree construction and scheduling rendering method for Urban 3D model based on weight. Divide Urban 3D model into different rendering weights according to certain rules, perform Quadtree construction and schedule rendering according to different rendering weights. Also proposed an algorithm for extracting bounding box extraction based on model drawing primitives to generate LOD model automatically. Using the algorithm proposed in this paper, developed a 3D urban planning&management software, the practice has showed the algorithm is efficient and feasible, the render frame rate of big scene and small scene are both stable at around 25 frames.

  19. Spacecraft attitude determination using the earth's magnetic field

    Science.gov (United States)

    Simpson, David G.

    1989-01-01

    A method is presented by which the attitude of a low-Earth orbiting spacecraft may be determined using a vector magnetometer, a digital Sun sensor, and a mathematical model of the Earth's magnetic field. The method is currently being implemented for the Solar Maximum Mission spacecraft (as a backup for the failing star trackers) as a way to determine roll gyro drift.

  20. The Dangling model in the construction of compound sentences with regard to verb tenses

    Directory of Open Access Journals (Sweden)

    Mahmoud Mehravaran

    2016-02-01

    the mistakes of some of the grammars. This research project has for the first time introduced constructive models of compound sentences in a comprehensive research taking in to account the tense of the verbs. The primary question in this research project is which kind of sentences can be considered as compound and what is the constructive of such a sentence? When defining a compound sentences, grammarians either shave the same beliefs or differ in their ideas. But all grammarians agree to the fact that a compound sentences has more than one verb. Different definitions are due to different criteria adapted in constructing a compound sentences. To construct a noun, and adjective, a verb and a sentence we should take similar and precise criteria to our consideration. In the grammatical units of noun, adjectives, and verbs construction means connecting two or more parts that can convey one similar meaning and its parts are dependent upon one another.  In the construction of compound sentences there must be the same criteria so that its applications can be truly recognized and identified just like the previously mentioned grammatical units. The first step to arrive at a criterion in defining and identifying compound sentences, is to separate this discussion from connective sentences that are relate to each other with connectives are called connective sentences. But sentences which are constructed with dependent making connectives and their parts are dependent upon one another are called compound sentences. Therefore the signs of compound sentences with regard to constructions and the meaning of criterion are as follows: 1 They have more than one verb. 2 The consistence of two or more dependent phrases. 3 Phrases construct a complete sentences all together and convey one similar message. 4 One of the phrases is the main clause and the other one is the subordinate one. 5 The phrases or subordinate clauses can be related to one of the major parts and they can take a

  1. The Dangling model in the construction of compound sentences with regard to verb tenses

    Directory of Open Access Journals (Sweden)

    Mahmoud Mehravaran

    2016-01-01

    the mistakes of some of the grammars. This research project has for the first time introduced constructive models of compound sentences in a comprehensive research taking in to account the tense of the verbs. The primary question in this research project is which kind of sentences can be considered as compound and what is the constructive of such a sentence? When defining a compound sentences, grammarians either shave the same beliefs or differ in their ideas. But all grammarians agree to the fact that a compound sentences has more than one verb. Different definitions are due to different criteria adapted in constructing a compound sentences. To construct a noun, and adjective, a verb and a sentence we should take similar and precise criteria to our consideration. In the grammatical units of noun, adjectives, and verbs construction means connecting two or more parts that can convey one similar meaning and its parts are dependent upon one another.  In the construction of compound sentences there must be the same criteria so that its applications can be truly recognized and identified just like the previously mentioned grammatical units. The first step to arrive at a criterion in defining and identifying compound sentences, is to separate this discussion from connective sentences that are relate to each other with connectives are called connective sentences. But sentences which are constructed with dependent making connectives and their parts are dependent upon one another are called compound sentences. Therefore the signs of compound sentences with regard to constructions and the meaning of criterion are as follows: 1 They have more than one verb. 2 The consistence of two or more dependent phrases. 3 Phrases construct a complete sentences all together and convey one similar message. 4 One of the phrases is the main clause and the other one is the subordinate one. 5 The phrases or subordinate clauses can be related to one of the major parts and they can take a

  2. MIDN: A spacecraft Micro-dosimeter mission

    International Nuclear Information System (INIS)

    Pisacane, V. L.; Ziegler, J. F.; Nelson, M. E.; Caylor, M.; Flake, D.; Heyen, L.; Youngborg, E.; Rosenfeld, A. B.; Cucinotta, F.; Zaider, M.; Dicello, J. F.

    2006-01-01

    MIDN (Micro-dosimetry instrument) is a payload on the MidSTAR-I spacecraft (Midshipman Space Technology Applications Research) under development at the United States Naval Academy. MIDN is a solid-state system being designed and constructed to measure Micro-dosimetric spectra to determine radiation quality factors for space environments. Radiation is a critical threat to the health of astronauts and to the success of missions in low-Earth orbit and space exploration. The system will consist of three separate sensors, one external to the spacecraft, one internal and one embedded in polyethylene. Design goals are mass <3 kg and power <2 W. The MidSTAR-I mission in 2006 will provide an opportunity to evaluate a preliminary version of this system. Its low power and mass makes it useful for the International Space Station and manned and unmanned interplanetary missions as a real-time system to assess and alert astronauts to enhanced radiation environments. (authors)

  3. Utilization of building information modeling in infrastructure’s design and construction

    Science.gov (United States)

    Zak, Josef; Macadam, Helen

    2017-09-01

    Building Information Modeling (BIM) is a concept that has gained its place in the design, construction and maintenance of buildings in Czech Republic during recent years. This paper deals with description of usage, applications and potential benefits and disadvantages connected with implementation of BIM principles in the preparation and construction of infrastructure projects. Part of the paper describes the status of BIM implementation in Czech Republic, and there is a review of several virtual design and construction practices in Czech Republic. Examples of best practice are presented from current infrastructure projects. The paper further summarizes experiences with new technologies gained from the application of BIM related workflows. The focus is on the BIM model utilization for the machine control systems on site, quality assurance, quality management and construction management.

  4. Application of 3-Dimensional Printing Technology to Construct an Eye Model for Fundus Viewing Study

    OpenAIRE

    Xie, Ping; Hu, Zizhong; Zhang, Xiaojun; Li, Xinhua; Gao, Zhishan; Yuan, Dongqing; Liu, Qinghuai

    2014-01-01

    Objective To construct a life-sized eye model using the three-dimensional (3D) printing technology for fundus viewing study of the viewing system. Methods We devised our schematic model eye based on Navarro's eye and redesigned some parameters because of the change of the corneal material and the implantation of intraocular lenses (IOLs). Optical performance of our schematic model eye was compared with Navarro's schematic eye and other two reported physical model eyes using the ZEMAX optical ...

  5. A Critical Review of Construct Indicators and Measurement Model Misspecification in Marketing and Consumer Research.

    OpenAIRE

    Jarvis, Cheryl Burke; MacKenzie, Scott B; Podsakoff, Philip M

    2003-01-01

    A review of the literature suggests that few studies use formative indicator measurement models, even though they should. Therefore, the purpose of this research is to (a) discuss the distinction between formative and reflective measurement models, (b) develop a set of conceptual criteria that can be used to determine whether a construct should be modeled as having formative or reflective indicators, (c) review the marketing literature to obtain an estimate of the extent of measurement model ...

  6. A Research on the E-commerce Applied to the Construction of Marketing Model

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The function of E-commerce is becoming more and more widely applied to many fields,which bring about some new challenges and opportunities for the construction of marketing model.It is proved that the more E-com- merce applied to the construction of marketing,the more precision of forecast for the enterprises can acquire,which is very helpful for the production and marketing of enterprises.Therefore,the research on the E-commerce applied to the construction of marketing is popular today.This paper applie...

  7. Model Configuration and Innovative Design of College Students’ Ecological Civilization Construction

    Science.gov (United States)

    Chengwen, Yang

    2018-02-01

    This study is based on Marxist eco-civilization thought, combining with Eco management theory, puts forward solutions for college students’ ecological civilization construction. The paper based on the perspective of ecological management theory to analyze the main elements of eco-civilization construction of college students, mainly including five categories. In view of above-mentioned analyze, constructed the model of college students’ eco-civilization which is based on the theory of eco-management, and put forward on concrete methods to improve it.

  8. Why a Train Set Helps Participants Co-Construct Meaning in Business Model Innovation

    DEFF Research Database (Denmark)

    Beuthel, Maria Rosa; Buur, Jacob

    In this position paper we show how participants in an innovation workshop employ tangible material – a toy train set – to co-construct understandings of a new business model. In multidisciplinary teams the process of developing new terms and concepts together is crucial for work to progress. Every...... to understand how they construct a concept. We observe that the final result of the workshop is indeed innovative and is co-constructed by all group members. We discuss why the toy train works: It keeps both hands and mind busy, it allows silent participation, and it expands the vocabulary of the discussion....

  9. Collaborative Management of Complex Major Construction Projects: AnyLogic-Based Simulation Modelling

    Directory of Open Access Journals (Sweden)

    Na Zhao

    2016-01-01

    Full Text Available Complex supply chain system collaborative management of major construction projects effectively integrates the different participants in the construction project. This paper establishes a simulation model based on AnyLogic to reveal the collaborative elements in the complex supply chain management system and the modes of action as well as the transmission problems of the intent information. Thus it is promoting the participants to become an organism with coordinated development and coevolution. This study can help improve the efficiency and management of the complex system of major construction projects.

  10. Model and Algorithm for Substantiating Solutions for Organization of High-Rise Construction Project

    Directory of Open Access Journals (Sweden)

    Anisimov Vladimir

    2018-01-01

    Full Text Available In the paper the models and the algorithm for the optimal plan formation for the organization of the material and logistical processes of the high-rise construction project and their financial support are developed. The model is based on the representation of the optimization procedure in the form of a non-linear problem of discrete programming, which consists in minimizing the execution time of a set of interrelated works by a limited number of partially interchangeable performers while limiting the total cost of performing the work. The proposed model and algorithm are the basis for creating specific organization management methodologies for the high-rise construction project.

  11. Model and Algorithm for Substantiating Solutions for Organization of High-Rise Construction Project

    Science.gov (United States)

    Anisimov, Vladimir; Anisimov, Evgeniy; Chernysh, Anatoliy

    2018-03-01

    In the paper the models and the algorithm for the optimal plan formation for the organization of the material and logistical processes of the high-rise construction project and their financial support are developed. The model is based on the representation of the optimization procedure in the form of a non-linear problem of discrete programming, which consists in minimizing the execution time of a set of interrelated works by a limited number of partially interchangeable performers while limiting the total cost of performing the work. The proposed model and algorithm are the basis for creating specific organization management methodologies for the high-rise construction project.

  12. Design, construction, and evaluation of a 1:8 scale model binaural manikin.

    Science.gov (United States)

    Robinson, Philip; Xiang, Ning

    2013-03-01

    Many experiments in architectural acoustics require presenting listeners with simulations of different rooms to compare. Acoustic scale modeling is a feasible means to create accurate simulations of many rooms at reasonable cost. A critical component in a scale model room simulation is a receiver that properly emulates a human receiver. For this purpose, a scale model artificial head has been constructed and tested. This paper presents the design and construction methods used, proper equalization procedures, and measurements of its response. A headphone listening experiment examining sound externalization with various reflection conditions is presented that demonstrates its use for psycho-acoustic testing.

  13. Groundwater flow modeling in construction phase of the Mizunami Underground Research Laboratory project

    International Nuclear Information System (INIS)

    Onoe, Hironori; Saegusa, Hiromitsu; Takeuchi, Ryuji

    2016-01-01

    This paper comprehensively describes the result of groundwater flow modeling using data of hydraulic responses due to construction of Mizunami Underground Research Laboratory (MIU) in Mizunami, Gifu, in order to update hydrogeological model based on stepwise approach for crystalline fractured rock in Japan. The results showed that large scale hydraulic compartment structures which has significant influence on change of groundwater flow characteristics are distributed around MIU. Furthermore, it is concluded that hydrogeological monitoring data and groundwater flow modeling during construction of deep underground facilities are effective for hydrogeological characterization of heterogeneous fractured rock. (author)

  14. Mathematical model of mechanical testing of bone-implant (4.5 mm LCP construct

    Directory of Open Access Journals (Sweden)

    Lucie Urbanová

    2012-01-01

    Full Text Available The study deals with the possibility of substituting time- and material-demanding mechanical testing of a bone defect fixation by mathematical modelling. Based on the mechanical model, a mathematical model of bone-implant construct stabilizing experimental segmental femoral bone defect (segmental ostectomy in a miniature pig ex vivo model using 4.5 mm titanium LCP was created. It was subsequently computer-loaded by forces acting parallel to the long axis of the construct. By the effect of the acting forces the displacement vector sum of individual construct points occurred. The greatest displacement was noted in the end segments of the bone in close proximity to ostectomy and in the area of the empty central plate hole (without screw at the level of the segmental bone defect. By studying the equivalent von Mises stress σEQV on LCP as part of the tested construct we found that the greatest changes of stress occur in the place of the empty central plate hole. The distribution of this strain was relatively symmetrical along both sides of the hole. The exceeding of the yield stress value and irreversible plastic deformations in this segment of LCP occurred at the acting of the force of 360 N. These findings are in line with the character of damage of the same construct loaded during its mechanic testing. We succeeded in creating a mathematical model of the bone-implant construct which may be further used for computer modelling of real loading of similar constructs chosen for fixation of bone defects in both experimental and clinical practice.

  15. Numerical analysis of the construction of Odelouca Dam using a Subloading Surface Soil Model

    OpenAIRE

    Brito, A.; Maranha, J. R.; Caldeira, L.

    2014-01-01

    Odelouca dam is an embankment dam, with 76 m height, recently constructed in the south of Portugal. It is zoned with a core consisting of colluvial and residual schist soil, and with soil-rockfill mixtures making up the shells (weathered schist with a significant fraction of coarse sized particles). This paper presents a numerical analysis of Odelouca dam construction. In this analysis the explicit finite difference program FLAC is used. An unconventional elastoplastic soil model, a Subloadin...

  16. BARRIERS AND CHALLENGES OF BUILDING INFORMATION MODELLING IMPLEMENTATION IN JORDANIAN CONSTRUCTION INDUSTRY

    OpenAIRE

    Mohammed A.KA. AL-Btoush*, Ahmad Tarmizi Haron

    2017-01-01

    Construction companies are faced with the need to innovatively integrate the construction process and address project development challenges. One way of doing that is the integration of building information modelling (BIM) in the building design and development cycles. However, due to the lack of clear understanding and the absence of a holistic implementation guideline, many companies are unable to fully achieve BIM potentials or implement BIM in their project and building lifecycle. BIM imp...

  17. A model of how features of construction projects influence accident occurrence

    OpenAIRE

    Manu, P.

    2017-01-01

    This book chapter in "Valuing People in Construction" (edited by Emuze, F. and Smallwood, J.) presents a study which sought empirical verification of a model of how construction project features (CPFs) influence accident occurrence. A qualitative strategy, in particular phenomenology, involving a range of in-depth interviews with practitioners was used and the findings were subsequently validated using a credibility check involving a survey. Altogether, the findings of the interviews and cred...

  18. ANALYSIS OF FUNNELS EVALUATION MODEL BY THE “CONSTRUCTION-SOIL” SYSTEM

    Directory of Open Access Journals (Sweden)

    A. S. Koretskiy

    2010-04-01

    Full Text Available Recently in the European countries the designs of flexible pipes and pipe bridges, the bearing capacity of which is provided by passive resistance of soil, have found more applications. The paper presents an analysis of existing models for calculating flexible pipes working as a system «construction-soil». The numerical example for calculating such construction design using software package SCAD is given.

  19. An Integrated Framework for Process-Driven Model Construction in Disease Ecology and Animal Health.

    Science.gov (United States)

    Mancy, Rebecca; Brock, Patrick M; Kao, Rowland R

    2017-01-01

    Process models that focus on explicitly representing biological mechanisms are increasingly important in disease ecology and animal health research. However, the large number of process modelling approaches makes it difficult to decide which is most appropriate for a given disease system and research question. Here, we discuss different motivations for using process models and present an integrated conceptual analysis that can be used to guide the construction of infectious disease process models and comparisons between them. Our presentation complements existing work by clarifying the major differences between modelling approaches and their relationship with the biological characteristics of the epidemiological system. We first discuss distinct motivations for using process models in epidemiological research, identifying the key steps in model design and use associated with each. We then present a conceptual framework for guiding model construction and comparison, organised according to key aspects of epidemiological systems. Specifically, we discuss the number and type of disease states, whether to focus on individual hosts (e.g., cows) or groups of hosts (e.g., herds or farms), how space or host connectivity affect disease transmission, whether demographic and epidemiological processes are periodic or can occur at any time, and the extent to which stochasticity is important. We use foot-and-mouth disease and bovine tuberculosis in cattle to illustrate our discussion and support explanations of cases in which different models are used to address similar problems. The framework should help those constructing models to structure their approach to modelling decisions and facilitate comparisons between models in the literature.

  20. Item Construction Using Reflective, Formative, or Rasch Measurement Models: Implications for Group Work

    Science.gov (United States)

    Peterson, Christina Hamme; Gischlar, Karen L.; Peterson, N. Andrew

    2017-01-01

    Measures that accurately capture the phenomenon are critical to research and practice in group work. The vast majority of group-related measures were developed using the reflective measurement model rooted in classical test theory (CTT). Depending on the construct definition and the measure's purpose, the reflective model may not always be the…

  1. Modeling of Aircraft Deicing Fluid Induced Biochemical Oxygen Demand in Subsurface-Flow Constructed Treatment Wetlands

    Science.gov (United States)

    2009-03-01

    Jukka A. Rintala, Christof Holliger, and Alla N. Nozhevnikova. “Evaluation of Kinetic Coefficients Using Intergrated Monod and Haldane Models for...Rousseau, Diederik P. L., Peter A Vanrolleghem, and Niels De Pauw. “Model-Based Design of Horizontal Subsurface Flow constructed Treatment

  2. Integrated emerging contractor development model for the construction industry: practical implementation and statistical quantification

    CSIR Research Space (South Africa)

    Hauptfleisch, Dries

    2007-05-01

    Full Text Available , in the shortest possible time. An empowered model has thus been created to ensure the rapid development of emerging construction contractors. This model has a sound theoretical base, is supported by extensive filed research and has been introduced in practice...

  3. Videogame Construction by Engineering Students for Understanding Modelling Processes: The Case of Simulating Water Behaviour

    Science.gov (United States)

    Pretelín-Ricárdez, Angel; Sacristán, Ana Isabel

    2015-01-01

    We present some results of an ongoing research project where university engineering students were asked to construct videogames involving the use of physical systems models. The objective is to help them identify and understand the elements and concepts involved in the modelling process. That is, we use game design as a constructionist approach…

  4. Dynamic Processes of Conceptual Change: Analysis of Constructing Mental Models of Chemical Equilibrium.

    Science.gov (United States)

    Chiu, Mei-Hung; Chou, Chin-Cheng; Liu, Chia-Ju

    2002-01-01

    Investigates students' mental models of chemical equilibrium using dynamic science assessments. Reports that students at various levels have misconceptions about chemical equilibrium. Involves 10th grade students (n=30) in the study doing a series of hands-on chemical experiments. Focuses on the process of constructing mental models, dynamic…

  5. Identifying Multiple Levels of Discussion-Based Teaching Strategies for Constructing Scientific Models

    Science.gov (United States)

    Williams, Grant; Clement, John

    2015-01-01

    This study sought to identify specific types of discussion-based strategies that two successful high school physics teachers using a model-based approach utilized in attempting to foster students' construction of explanatory models for scientific concepts. We found evidence that, in addition to previously documented dialogical strategies that…

  6. DEVELOPING A MODEL TO ENHANCE LABOR PRODUCTIVITY USING BRIDGE CONSTRUCTION BENCHMARK DATA

    Directory of Open Access Journals (Sweden)

    Seonghoon Kim

    2013-07-01

    Full Text Available The Labor Working Status Monitoring (LWSM Model that incorporates the WRITE and the industry benchmark data was developed through the five steps to enhance labor producitivty in bridge construction operations. The first step of the development process was to conduct a literature review, followed by the second step which was to develop the WRITE. During the development, the authors identified the necessary hardware and software for the WRITE and outlined a schematic to show the connection of major hardware components. The third step was to develop the LWSM Model for monitoring the on-site construction labor working status by comparing data from the WRITE with the industry benchmark data. A survey methodology was used to acquire industry benchmark data from bridge construction experts. The fourth step was to demonstrate the implementation of the LWSM Model at a bridge construction site. During this phase, labor working status data collected using the WRITE was compared with the benchmark data to form the basis for the project managers and engineers to make efficiency improvement decisions. Finally, research findings and recommendations for future research were outlined. The success of this research made several contributions to the advancement of bridge construction. First, it advances the application of wireless technology in construction management. Second, it provides an advanced technology for project managers and engineers to share labor working status information among project participants. Finally, using the developed technology, project managers and engineers can quickly identify labor efficiency problems and take action to address these problems.

  7. Study of the two-dimensional Hubbard model at half-filling through constructive methods; Etude du modele de Hubbard bidimensionnel a demi remplissage par des methodes constructives

    Energy Technology Data Exchange (ETDEWEB)

    Afchain, St

    2005-02-15

    The Hubbard model is the simplest model to describe the behaviour of fermions on a network, it takes into account only fermion scattering and only interactions with other fermions located on the same site. Half-filling means that the total number of fermions is equal to half the number of sites. In the first chapter we show how we can pass trough successive approximations from a very general Hamiltonian to the Hubbard Hamiltonian. The second chapter is dedicated to the passage from the Hamiltonian formalism to the Grassmanian functional formalism. The main idea is to show that the correlation functions of the Hamiltonian approach can be described through fermionic functional integrals which implies the possibility of speaking of the model in terms of field theory. The chapter 3 deals with the main constructive techniques that allow the strict and consistent construction of models inside the frame of field theory. We show by proving the violation of a condition concerning self-energy, that the two-dimensional Hubbard model at half-filling has not the behaviour of a Fermi liquid in the Landau's interpretation. (A.C.)

  8. Programming While Construction of Engineering 3D Models of Complex Geometry

    Science.gov (United States)

    Kheyfets, A. L.

    2017-11-01

    The capabilities of geometrically accurate computational 3D models construction with the use of programming are presented. The construction of models of an architectural arch and a glo-boid worm gear is considered as an example. The models are designed in the AutoCAD pack-age. Three programs of construction are given. The first program is for designing a multi-section architectural arch. The control of the arch’s geometry by impacting its main parameters is shown. The second program is for designing and studying the working surface of a globoid gear’s worm. The article shows how to make the animation for this surface’s formation. The third program is for formation of a worm gear cavity surface. The cavity formation dynamics is studied. The programs are written in the AutoLisp programming language. The program texts are provided.

  9. A software complex intended for constructing applied models and meta-models on the basis of mathematical programming principles

    Directory of Open Access Journals (Sweden)

    Михаил Юрьевич Чернышов

    2013-12-01

    Full Text Available A software complex (SC elaborated by the authors on the basis of the language LMPL and representing a software tool intended for synthesis of applied software models and meta-models constructed on the basis of mathematical programming (MP principles is described. LMPL provides for an explicit form of declarative representation of MP-models, presumes automatic constructing and transformation of models and the capability of adding external software packages. The following software versions of the SC have been implemented: 1 a SC intended for representing the process of choosing an optimal hydroelectric power plant model (on the principles of meta-modeling and 2 a SC intended for representing the logic-sense relations between the models of a set of discourse formations in the discourse meta-model.

  10. Small Spacecraft for Planetary Science

    Science.gov (United States)

    Baker, John; Castillo-Rogez, Julie; Bousquet, Pierre-W.; Vane, Gregg; Komarek, Tomas; Klesh, Andrew

    2016-07-01

    As planetary science continues to explore new and remote regions of the Solar system with comprehensive and more sophisticated payloads, small spacecraft offer the possibility for focused and more affordable science investigations. These small spacecraft or micro spacecraft (attitude control and determination, capable computer and data handling, and navigation are being met by technologies currently under development to be flown on CubeSats within the next five years. This paper will discuss how micro spacecraft offer an attractive alternative to accomplish specific science and technology goals and what relevant technologies are needed for these these types of spacecraft. Acknowledgements: Part of this work is being carried out at the Jet Propulsion Laboratory, California Institute of Technology under contract to NASA. Government sponsorship acknowledged.

  11. Factors Influencing Implementation of OHSAS 18001 in Indian Construction Organizations: Interpretive Structural Modeling Approach.

    Science.gov (United States)

    Rajaprasad, Sunku Venkata Siva; Chalapathi, Pasupulati Venkata

    2015-09-01

    Construction activity has made considerable breakthroughs in the past two decades on the back of increases in development activities, government policies, and public demand. At the same time, occupational health and safety issues have become a major concern to construction organizations. The unsatisfactory safety performance of the construction industry has always been highlighted since the safety management system is neglected area and not implemented systematically in Indian construction organizations. Due to a lack of enforcement of the applicable legislation, most of the construction organizations are forced to opt for the implementation of Occupational Health Safety Assessment Series (OHSAS) 18001 to improve safety performance. In order to better understand factors influencing the implementation of OHSAS 18001, an interpretive structural modeling approach has been applied and the factors have been classified using matrice d'impacts croises-multiplication appliqué a un classement (MICMAC) analysis. The study proposes the underlying theoretical framework to identify factors and to help management of Indian construction organizations to understand the interaction among factors influencing in implementation of OHSAS 18001. Safety culture, continual improvement, morale of employees, and safety training have been identified as dependent variables. Safety performance, sustainable construction, and conducive working environment have been identified as linkage variables. Management commitment and safety policy have been identified as the driver variables. Management commitment has the maximum driving power and the most influential factor is safety policy, which states clearly the commitment of top management towards occupational safety and health.

  12. AN ANALYSIS OF ACCIDENT TRENDS AND MODELING OF SAFETY INDICES IN AN INDIAN CONSTRUCTION ORGANIZATION

    Directory of Open Access Journals (Sweden)

    Sunku Venkata Siva Rajaprasad

    2016-09-01

    Full Text Available Construction industry has been recognized as a hazardous industry in many countries due to distinct nature of execution of works.The accident rate in construction sector is high all over the world due to dynamic nature of work activities. Occurrence of accidents and its severity in construction industry is several times higher than the manufacturing industries. The study was limited to a major construction organization in India to examine the trends in construction accidents for the period 2008-2014. In India, safety performance is gauged basing on safety indices; frequency, severity and incidence rates. It is not practicable to take decisions or to implement safety strategies on the basis of indices. The data used for this study was collected from a leading construction organization involved in execution of major construction activities all over India and abroad. The multiple regression method was adopted to model the pattern of safety indices wise .The pattern showed that significant relationships exist between the three safety indices and the related independent variables.

  13. An Environmental Management Maturity Model of Construction Programs Using the AHP-Entropy Approach

    Directory of Open Access Journals (Sweden)

    Libiao Bai

    2018-06-01

    Full Text Available The accelerating process of urbanization in China has led to considerable opportunities for the development of construction projects, however, environmental issues have become an important constraint on the implementation of these projects. To quantitatively describe the environmental management capabilities of such projects, this paper proposes a 2-dimensional Environmental Management Maturity Model of Construction Program (EMMMCP based on an analysis of existing projects, group management theory and a management maturity model. In this model, a synergetic process was included to compensate for the lack of consideration of synergies in previous studies, and it was involved in the construction of the first dimension, i.e., the environmental management index system. The second dimension, i.e., the maturity level of environment management, was then constructed by redefining the hierarchical characteristics of construction program (CP environmental management maturity. Additionally, a mathematical solution to this proposed model was derived via the Analytic Hierarchy Process (AHP-entropy approach. To verify the effectiveness and feasibility of this proposed model, a computational experiment was conducted, and the results show that this approach could not only measure the individual levels of different processes, but also achieve the most important objective of providing a reference for stakeholders when making decisions on the environmental management of construction program, which reflects this model is reasonable for evaluating the level of environmental management maturity in CP. To our knowledge, this paper is the first study to evaluate the environmental management maturity levels of CP, which would fill the gap between project program management and environmental management and provide a reference for relevant management personnel to enhance their environmental management capabilities.

  14. System Dynamics Model and Simulation of Employee Work-Family Conflict in the Construction Industry

    Science.gov (United States)

    Wu, Guangdong; Duan, Kaifeng; Zuo, Jian; Yang, Jianlin; Wen, Shiping

    2016-01-01

    The construction industry is a demanding work environment where employees’ work-family conflict is particularly prominent. This conflict has a significant impact on job and family satisfaction and performance of employees. In order to analyze the dynamic evolution of construction industry employee’s work-family conflict between work and family domains, this paper constructs a bi-directional dynamic model framework of work-family conflict by referring to the relevant literature. Consequently, a system dynamics model of employee’s work-family conflict in the construction industry is established, and a simulation is conducted. The simulation results indicate that construction industry employees experience work interference with family conflict (WIFC) levels which are significantly greater than the family interference with work conflict (FIWC) levels. This study also revealed that improving work flexibility and organizational support can have a positive impact on the satisfaction and performance of construction industry employees from a work and family perspective. Furthermore, improving family support can only significantly improve employee job satisfaction. PMID:27801857

  15. System Dynamics Model and Simulation of Employee Work-Family Conflict in the Construction Industry

    Directory of Open Access Journals (Sweden)

    Guangdong Wu

    2016-10-01

    Full Text Available The construction industry is a demanding work environment where employees’ work-family conflict is particularly prominent. This conflict has a significant impact on job and family satisfaction and performance of employees. In order to analyze the dynamic evolution of construction industry employee’s work-family conflict between work and family domains, this paper constructs a bi-directional dynamic model framework of work-family conflict by referring to the relevant literature. Consequently, a system dynamics model of employee’s work-family conflict in the construction industry is established, and a simulation is conducted. The simulation results indicate that construction industry employees experience work interference with family conflict (WIFC levels which are significantly greater than the family interference with work conflict (FIWC levels. This study also revealed that improving work flexibility and organizational support can have a positive impact on the satisfaction and performance of construction industry employees from a work and family perspective. Furthermore, improving family support can only significantly improve employee job satisfaction.

  16. System Dynamics Model and Simulation of Employee Work-Family Conflict in the Construction Industry.

    Science.gov (United States)

    Wu, Guangdong; Duan, Kaifeng; Zuo, Jian; Yang, Jianlin; Wen, Shiping

    2016-10-28

    The construction industry is a demanding work environment where employees' work-family conflict is particularly prominent. This conflict has a significant impact on job and family satisfaction and performance of employees. In order to analyze the dynamic evolution of construction industry employee's work-family conflict between work and family domains, this paper constructs a bi-directional dynamic model framework of work-family conflict by referring to the relevant literature. Consequently, a system dynamics model of employee's work-family conflict in the construction industry is established, and a simulation is conducted. The simulation results indicate that construction industry employees experience work interference with family conflict (WIFC) levels which are significantly greater than the family interference with work conflict (FIWC) levels. This study also revealed that improving work flexibility and organizational support can have a positive impact on the satisfaction and performance of construction industry employees from a work and family perspective. Furthermore, improving family support can only significantly improve employee job satisfaction.

  17. Computational model-informed design and bioprinting of cell-patterned constructs for bone tissue engineering.

    Science.gov (United States)

    Carlier, Aurélie; Skvortsov, Gözde Akdeniz; Hafezi, Forough; Ferraris, Eleonora; Patterson, Jennifer; Koç, Bahattin; Van Oosterwyck, Hans

    2016-05-17

    Three-dimensional (3D) bioprinting is a rapidly advancing tissue engineering technology that holds great promise for the regeneration of several tissues, including bone. However, to generate a successful 3D bone tissue engineering construct, additional complexities should be taken into account such as nutrient and oxygen delivery, which is often insufficient after implantation in large bone defects. We propose that a well-designed tissue engineering construct, that is, an implant with a specific spatial pattern of cells in a matrix, will improve the healing outcome. By using a computational model of bone regeneration we show that particular cell patterns in tissue engineering constructs are able to enhance bone regeneration compared to uniform ones. We successfully bioprinted one of the most promising cell-gradient patterns by using cell-laden hydrogels with varying cell densities and observed a high cell viability for three days following the bioprinting process. In summary, we present a novel strategy for the biofabrication of bone tissue engineering constructs by designing cell-gradient patterns based on a computational model of bone regeneration, and successfully bioprinting the chosen design. This integrated approach may increase the success rate of implanted tissue engineering constructs for critical size bone defects and also can find a wider application in the biofabrication of other types of tissue engineering constructs.

  18. Developing a system dynamics model to analyse environmental problem in construction site

    Science.gov (United States)

    Haron, Fatin Fasehah; Hawari, Nurul Nazihah

    2017-11-01

    This study aims to develop a system dynamics model at a construction site to analyse the impact of environmental problem. Construction sites may cause damages to the environment, and interference in the daily lives of residents. A proper environmental management system must be used to reduce pollution, enhance bio-diversity, conserve water, respect people and their local environment, measure performance and set targets for the environment and sustainability. This study investigates the damaging impact normally occur during the construction stage. Environmental problem will cause costly mistake in project implementation, either because of the environmental damages that are likely to arise during project implementation, or because of modification that may be required subsequently in order to make the action environmentally acceptable. Thus, findings from this study has helped in significantly reducing the damaging impact towards environment, and improve the environmental management system performance at construction site.

  19. A two-phase moisture transport model accounting for sorption hysteresis in layered porous building constructions

    DEFF Research Database (Denmark)

    Johannesson, Björn; Janz, Mårten

    2009-01-01

    Building constructions most commonly consists of layered porous materials such as masonry on bricks. The moisture distribution and its variations due to change in surrounding environment is of special interest in such layered construction since materials adsorb different amounts of water and exhi......Building constructions most commonly consists of layered porous materials such as masonry on bricks. The moisture distribution and its variations due to change in surrounding environment is of special interest in such layered construction since materials adsorb different amounts of water....... The model is developed by carefully examining the mass balance postulates for the two considered constituents together with appropriate and suitable constitutive assumptions. A test example is solved by using an implemented implicit finite element code which uses a modified Newton-Raphson scheme to tackle...

  20. High-rise construction in the Russian economy: modeling of management decisions

    Science.gov (United States)

    Miroshnikova, Tatyana; Taskaeva, Natalia

    2018-03-01

    The growth in the building industry, particularly in residential high-rise construction, is having considerable influence on the country's economic development. The scientific hypothesis of the research is that the execution of town-planning programs of high-rise construction depends to a large extent on the management of the provision of material resources for the construction of a millionth city, while the balance model is the most important tool for establishing and determining the ratio between supply and demand for material resources. In order to improve the efficiency of high-rise building management, it is proposed to develop a methodology for managing the provision of construction of large cities with material resources.

  1. Benefits of Building Information Modelling in the Project Lifecycle: Construction Projects in Asia

    Directory of Open Access Journals (Sweden)

    Jian Li

    2014-08-01

    Full Text Available Building Information Modelling (BIM is a process involving the creation and management of objective data with property, unique identity and relationship. In the Architecture, Engineering and Construction (AEC industry, BIM is adopted a lot in the lifecycle of buildings because of the high integration of information that it enables. Four-dimensional (4D computer-aided design (CAD has been adopted for many years to improve the construction planning process. BIM is adopted throughout buildings' lifecycles, in design, construction and operation. This paper presents five large-scale public and financial projects that adopt BIM in the design, construction and operational phases. Different uses of BIM are compared and contrasted in the context of the separate backgrounds. It is concluded that productivity is improved where BIM is used to enable easy sharing and integration of information and convenient collaboration.

  2. Modelling of project cash flow on construction projects in Malang city

    Science.gov (United States)

    Djatmiko, Bambang

    2017-09-01

    Contractors usually prepare a project cash flow (PCF) on construction projects. The flow of cash in and cash out within a construction project may vary depending on the owner, contract documents, and construction service providers who have their own authority. Other factors affecting the PCF are down payment, termyn, progress schedule, material schedule, equipment schedule, manpower schedules, and wages of workers and subcontractors. This study aims to describe the cash inflow and cash outflow based on the empirical data obtained from contractors, develop a PCF model based on Halpen & Woodhead's PCF model, and investigate whether or not there is a significant difference between the Halpen & Woodhead's PCF model and the empirical PCF model. Based on the researcher's observation, the PCF management has never been implemented by the contractors in Malang in serving their clients (owners). The research setting is in Malang City because physical development in all field and there are many new construction service providers. The findings in this current study are summarised as follows: 1) Cash in included current assets (20%), owner's down payment (20%), termyin I (5%-25%), termyin II (20%), termyin III (25%), termyin IV (25%) and retention (5%). Cash out included direct cost (65%), indirect cost (20%), and profit + informal cost(15%), 2)the construction work involving the empirical PCF model in this study was started with the funds obtained from DP or current assets and 3) The two models bear several similarities in the upward trends of direct cost, indirect cost, Pro Ic, progress billing, and S-curve. The difference between the two models is the occurrence of overdraft in the Halpen and Woodhead's PCF model only.

  3. Protecting Spacecraft Fragments from Exposure to Small Debris

    Directory of Open Access Journals (Sweden)

    V. V. Zelentsov

    2015-01-01

    less than 4 ... 5 km/s, at higher speeds particles breaks through them. As a result, a cloud is formed. It consists of fragments, destroying particle, and debris split-off from the obstacle. For reliable protection the sandwich panels are used. Shield design comprises two panels: the first panel being multi-layer and the second one being single-layer. The task of the first panel is to provide the maximum fragmented particle and reduce its speed. The second panel protects the structure from the cloud fragments resulting from breakdown of the first panel. The European module "Columbus” that is part of the ISS and transport vehicle ATV have the protective shield of the similar construction. The shield consists of "aluminum sheet with 2 mm thickness; filler - Kevlar + Nextel + epoxy resin, thermal insulation; the second panel comprises aluminum sheet of 3 mm thickness.Modeling and experiments show high efficiency of steel mesh as a protective shield. Spacecraft design consists, mainly, of aluminum alloys therefore space debris is from the same material. At collision with steel mesh a particle is decelerated and destroyed. Therefore, timeRushan ability of the particle significantly decreases. The second layer, opposing to the impact of high-speed particles, is foam metal (foam-Lumina. It is successfully used in the automotive engineering. Ballistic fabric (such as Kevlar is capable to protect from the effect of the fragmentation cloud.

  4. Printed Spacecraft Separation System

    Energy Technology Data Exchange (ETDEWEB)

    Dehoff, Ryan R [ORNL; Holmans, Walter [Planetary Systems Corporation

    2016-10-01

    In this project Planetary Systems Corporation proposed utilizing additive manufacturing (3D printing) to manufacture a titanium spacecraft separation system for commercial and US government customers to realize a 90% reduction in the cost and energy. These savings were demonstrated via “printing-in” many of the parts and sub-assemblies into one part, thus greatly reducing the labor associated with design, procurement, assembly and calibration of mechanisms. Planetary Systems Corporation redesigned several of the components of the separation system based on additive manufacturing principles including geometric flexibility and the ability to fabricate complex designs, ability to combine multiple parts of an assembly into a single component, and the ability to optimize design for specific mechanical property targets. Shock absorption was specifically targeted and requirements were established to attenuate damage to the Lightband system from shock of initiation. Planetary Systems Corporation redesigned components based on these requirements and sent the designs to Oak Ridge National Laboratory to be printed. ORNL printed the parts using the Arcam electron beam melting technology based on the desire for the parts to be fabricated from Ti-6Al-4V based on the weight and mechanical performance of the material. A second set of components was fabricated from stainless steel material on the Renishaw laser powder bed technology due to the improved geometric accuracy, surface finish, and wear resistance of the material. Planetary Systems Corporation evaluated these components and determined that 3D printing is potentially a viable method for achieving significant cost and savings metrics.

  5. Spectra and spacecraft

    Science.gov (United States)

    Moroz, V. I.

    2001-02-01

    In June 1999, Dr. Regis Courtin, Associate Editor of PSS, suggested that I write an article for the new section of this journal: "Planetary Pioneers". I hesitated , but decided to try. One of the reasons for my doubts was my primitive English, so I owe the reader an apology for this in advance. Writing took me much more time than I supposed initially, I have stopped and again returned to manuscript many times. My professional life may be divided into three main phases: pioneering work in ground-based IR astronomy with an emphasis on planetary spectroscopy (1955-1970), studies of the planets with spacecraft (1970-1989), and attempts to proceed with this work in difficult times. I moved ahead using the known method of trials and errors as most of us do. In fact, only a small percentage of efforts led to some important results, a sort of dry residue. I will try to describe below how has it been in my case: what may be estimated as the most important, how I came to this, what was around, etc.

  6. Research-Based Monitoring, Prediction, and Analysis Tools of the Spacecraft Charging Environment for Spacecraft Users

    Science.gov (United States)

    Zheng, Yihua; Kuznetsova, Maria M.; Pulkkinen, Antti A.; Maddox, Marlo M.; Mays, Mona Leila

    2015-01-01

    The Space Weather Research Center (http://swrc. gsfc.nasa.gov) at NASA Goddard, part of the Community Coordinated Modeling Center (http://ccmc.gsfc.nasa.gov), is committed to providing research-based forecasts and notifications to address NASA's space weather needs, in addition to its critical role in space weather education. It provides a host of services including spacecraft anomaly resolution, historical impact analysis, real-time monitoring and forecasting, tailored space weather alerts and products, and weekly summaries and reports. In this paper, we focus on how (near) real-time data (both in space and on ground), in combination with modeling capabilities and an innovative dissemination system called the integrated Space Weather Analysis system (http://iswa.gsfc.nasa.gov), enable monitoring, analyzing, and predicting the spacecraft charging environment for spacecraft users. Relevant tools and resources are discussed.

  7. Power Grid Construction Project Portfolio Optimization Based on Bi-level programming model

    Science.gov (United States)

    Zhao, Erdong; Li, Shangqi

    2017-08-01

    As the main body of power grid operation, county-level power supply enterprises undertake an important emission to guarantee the security of power grid operation and safeguard social power using order. The optimization of grid construction projects has been a key issue of power supply capacity and service level of grid enterprises. According to the actual situation of power grid construction project optimization of county-level power enterprises, on the basis of qualitative analysis of the projects, this paper builds a Bi-level programming model based on quantitative analysis. The upper layer of the model is the target restriction of the optimal portfolio; the lower layer of the model is enterprises’ financial restrictions on the size of the enterprise project portfolio. Finally, using a real example to illustrate operation proceeding and the optimization result of the model. Through qualitative analysis and quantitative analysis, the bi-level programming model improves the accuracy and normative standardization of power grid enterprises projects.

  8. A model for evaluating the social performance of construction waste management

    International Nuclear Information System (INIS)

    Yuan Hongping

    2012-01-01

    Highlights: ► Scant attention is paid to social performance of construction waste management (CWM). ► We develop a model for assessing the social performance of CWM. ► With the model, the social performance of CWM can be quantitatively simulated. - Abstract: It has been determined by existing literature that a lot of research efforts have been made to the economic performance of construction waste management (CWM), but less attention is paid to investigation of the social performance of CWM. This study therefore attempts to develop a model for quantitatively evaluating the social performance of CWM by using a system dynamics (SD) approach. Firstly, major variables affecting the social performance of CWM are identified and a holistic system for assessing the social performance of CWM is formulated in line with feedback relationships underlying these variables. The developed system is then converted into a SD model through the software iThink. An empirical case study is finally conducted to demonstrate application of the model. Results of model validation indicate that the model is robust and reasonable to reflect the situation of the real system under study. Findings of the case study offer helpful insights into effectively promoting the social performance of CWM of the project investigated. Furthermore, the model exhibits great potential to function as an experimental platform for dynamically evaluating effects of management measures on improving the social performance of CWM of construction projects.

  9. Group theoretical construction of two-dimensional models with infinite sets of conservation laws

    International Nuclear Information System (INIS)

    D'Auria, R.; Regge, T.; Sciuto, S.

    1980-01-01

    We explicitly construct some classes of field theoretical 2-dimensional models associated with symmetric spaces G/H according to a general scheme proposed in an earlier paper. We treat the SO(n + 1)/SO(n) and SU(n + 1)/U(n) case, giving their relationship with the O(n) sigma-models and the CP(n) models. Moreover, we present a new class of models associated to the SU(n)/SO(n) case. All these models are shown to possess an infinite set of local conservation laws. (orig.)

  10. Software for Engineering Simulations of a Spacecraft

    Science.gov (United States)

    Shireman, Kirk; McSwain, Gene; McCormick, Bernell; Fardelos, Panayiotis

    2005-01-01

    Spacecraft Engineering Simulation II (SES II) is a C-language computer program for simulating diverse aspects of operation of a spacecraft characterized by either three or six degrees of freedom. A functional model in SES can include a trajectory flight plan; a submodel of a flight computer running navigational and flight-control software; and submodels of the environment, the dynamics of the spacecraft, and sensor inputs and outputs. SES II features a modular, object-oriented programming style. SES II supports event-based simulations, which, in turn, create an easily adaptable simulation environment in which many different types of trajectories can be simulated by use of the same software. The simulation output consists largely of flight data. SES II can be used to perform optimization and Monte Carlo dispersion simulations. It can also be used to perform simulations for multiple spacecraft. In addition to its generic simulation capabilities, SES offers special capabilities for space-shuttle simulations: for this purpose, it incorporates submodels of the space-shuttle dynamics and a C-language version of the guidance, navigation, and control components of the space-shuttle flight software.

  11. Probing interferometric parallax with interplanetary spacecraft

    Science.gov (United States)

    Rodeghiero, G.; Gini, F.; Marchili, N.; Jain, P.; Ralston, J. P.; Dallacasa, D.; Naletto, G.; Possenti, A.; Barbieri, C.; Franceschini, A.; Zampieri, L.

    2017-07-01

    We describe an experimental scenario for testing a novel method to measure distance and proper motion of astronomical sources. The method is based on multi-epoch observations of amplitude or intensity correlations between separate receiving systems. This technique is called Interferometric Parallax, and efficiently exploits phase information that has traditionally been overlooked. The test case we discuss combines amplitude correlations of signals from deep space interplanetary spacecraft with those from distant galactic and extragalactic radio sources with the goal of estimating the interplanetary spacecraft distance. Interferometric parallax relies on the detection of wavefront curvature effects in signals collected by pairs of separate receiving systems. The method shows promising potentialities over current techniques when the target is unresolved from the background reference sources. Developments in this field might lead to the construction of an independent, geometrical cosmic distance ladder using a dedicated project and future generation instruments. We present a conceptual overview supported by numerical estimates of its performances applied to a spacecraft orbiting the Solar System. Simulations support the feasibility of measurements with a simple and time-saving observational scheme using current facilities.

  12. THE MODELLING OF ORGANIZATIONAL STRUCTURES OF MANAGEMENT BY REALIZING INVESTMENT CONSTRUCTION PROJECTS

    Directory of Open Access Journals (Sweden)

    Олег Александрович КУЧМА

    2016-03-01

    Full Text Available The authors consider the modeling of organizational structures by virtue of interaction between the basic participants by realizing of investment construction projects. This process is directed at the complex analysis of a problem of quality management by creating of building goods taking into account modern project management tendencies. The topicality of problem is obvious as by realizing of investment construction projects there is a liberal share of uncompleted projects, and in the completed projects actual values considerably exceed budgeted capital expenditures. The introduced model allows managing the project per quality system in all phases of the investment construction project‘s life cycle. It promotes refinement of building goods, improves the rate of successfully completed projects with actual values near budgeted.

  13. A Bibliometric Review on Risk Management and Building Information Modeling for International Construction

    Directory of Open Access Journals (Sweden)

    Tsenguun Ganbat

    2018-01-01

    Full Text Available International construction is complicated and involves high risks. However, with the development of technological innovation, Building Information Modeling (BIM emerged and seems to be able to address certain risks. To understand BIM applications in risk management for international construction, a state-of-the-art review is required. Therefore, this paper aims to identify the research trends and opportunities for risk management in BIM-enabled international construction by reviewing 526 peer-reviewed journal articles for the years 2007–2017. Thus five steps of bibliometric analysis were conducted based on the proposed frameworks of BIM risk management in international construction (BIM-RM-INTL. The results show that the popularization of BIM not only attracts all stakeholders’ interests but also brings some risks. For example, financial factors are hard to detect and control through BIM, information loss during transmission stands out, and BIM has no unified standards and regulations for international construction. The research has mapped existing research results and their relationships for future risk management in BIM-enabled international construction.

  14. Construct Validity of Fresh Frozen Human Cadaver as a Training Model in Minimal Access Surgery

    Science.gov (United States)

    Macafee, David; Pranesh, Nagarajan; Horgan, Alan F.

    2012-01-01

    Background: The construct validity of fresh human cadaver as a training tool has not been established previously. The aims of this study were to investigate the construct validity of fresh frozen human cadaver as a method of training in minimal access surgery and determine if novices can be rapidly trained using this model to a safe level of performance. Methods: Junior surgical trainees, novices (cadavers. Expert laparoscopists (>100 laparoscopic procedures) performed 3 repetitions of identical tasks. Performances were scored using a validated, objective Global Operative Assessment of Laparoscopic Skills scale. Scores for 3 consecutive repetitions were compared between experts and novices to determine construct validity. Furthermore, to determine if the novices reached a safe level, a trimmed mean of the experts score was used to define a benchmark. Mann-Whitney U test was used for construct validity analysis and 1-sample t test to compare performances of the novice group with the benchmark safe score. Results: Ten novices and 2 experts were recruited. Four out of 5 tasks (nondominant to dominant hand transfer; simulated appendicectomy; intracorporeal and extracorporeal knot tying) showed construct validity. Novices’ scores became comparable to benchmark scores between the eighth and tenth repetition. Conclusion: Minimal access surgical training using fresh frozen human cadavers appears to have construct validity. The laparoscopic skills of novices can be accelerated through to a safe level within 8 to 10 repetitions. PMID:23318058

  15. Construction of ground-state preserving sparse lattice models for predictive materials simulations

    Science.gov (United States)

    Huang, Wenxuan; Urban, Alexander; Rong, Ziqin; Ding, Zhiwei; Luo, Chuan; Ceder, Gerbrand

    2017-08-01

    First-principles based cluster expansion models are the dominant approach in ab initio thermodynamics of crystalline mixtures enabling the prediction of phase diagrams and novel ground states. However, despite recent advances, the construction of accurate models still requires a careful and time-consuming manual parameter tuning process for ground-state preservation, since this property is not guaranteed by default. In this paper, we present a systematic and mathematically sound method to obtain cluster expansion models that are guaranteed to preserve the ground states of their reference data. The method builds on the recently introduced compressive sensing paradigm for cluster expansion and employs quadratic programming to impose constraints on the model parameters. The robustness of our methodology is illustrated for two lithium transition metal oxides with relevance for Li-ion battery cathodes, i.e., Li2xFe2(1-x)O2 and Li2xTi2(1-x)O2, for which the construction of cluster expansion models with compressive sensing alone has proven to be challenging. We demonstrate that our method not only guarantees ground-state preservation on the set of reference structures used for the model construction, but also show that out-of-sample ground-state preservation up to relatively large supercell size is achievable through a rapidly converging iterative refinement. This method provides a general tool for building robust, compressed and constrained physical models with predictive power.

  16. Construction and Application Research of Isomap-RVM Credit Assessment Model

    Directory of Open Access Journals (Sweden)

    Guangrong Tong

    2015-01-01

    Full Text Available Credit assessment is the basis and premise of credit risk management systems. Accurate and scientific credit assessment is of great significance to the operational decisions of shareholders, corporate creditors, and management. Building a good and reliable credit assessment model is key to credit assessment. Traditional credit assessment models are constructed using the support vector machine (SVM combined with certain traditional dimensionality reduction algorithms. When constructing such a model, the dimensionality reduction algorithms are first applied to reduce the dimensions of the samples, so as to prevent the correlation of the samples’ characteristic index from being too high. Then, machine learning of the samples will be conducted using the SVM, in order to carry out classification assessment. To further improve the accuracy of credit assessment methods, this paper has introduced more cutting-edge algorithms, applied isometric feature mapping (Isomap for dimensionality reduction, and used the relevance vector machine (RVM for credit classification. It has constructed an Isomap-RVM model and used it to conduct financial analysis of China's listed companies. The empirical analysis shows that the credit assessment accuracy of the Isomap-RVM model is significantly higher than that of the Isomap-SVM model and slightly higher than that of the PCA-RVM model. It can correctly identify the credit risks of listed companies.

  17. Construction on the solution of osp(1/4) Toda model

    International Nuclear Information System (INIS)

    Yang Zhanying; Zhen Yi

    2000-01-01

    The Leznov-Saveliev algebraic analysis method and Drinfeld-Sokolov construction are applied to the supersymmetric case. In this approach, the authors obtained the solution of the osp(1/4) Toda model on the base of the Lie super algebra osp(1/4) and its highest weight by introducing chiral vectors. Therefore, the authors generalized this method to two rank case

  18. THREE-DIMENSIONAL GEOFILTRATIONAL MODEL OF THE ROGUN HYDRO POWER PLANT CONSTRUCTION SITE

    Directory of Open Access Journals (Sweden)

    Khokhotva Sergey Nikolaevich

    2017-05-01

    Full Text Available The article deals with technique of creation and results of calculations of the three-dimensional geofiltrational model of the Rogun HPP construction site. When performing works on creation of the Rogun HPP three-dimensional geofiltration model, geological and hydrogeological conditions of the Rogun HPP construction site were analyzed. They showed that the construction site consists mostly of fractured rocks of various weathering degrees. In terms of preservation, four preservation zones were identified in the rock mass. These zones define the features of hydrogeological conditions that have emerged in the area of construction. Calculation results illustrated the absence of seepage areas on the lower slope of dam; this is the indication of normal operation of the dam impervious circuit. The drainage system of the underground hydropower plant has a high efficiency. Operation of the drainage galleries complex leads to a significant reduction of piezometric pressure on roofs of the machine and transformer halls. Above the underground structures a completely drained area is formed. Completed forecast calculations on geofiltration model of the Rogun hydropower plant determine the hydrostatic pressure and piezometric pressure at any point of the modeled area. These data can be used as loads while designing of lining of underground workings.

  19. Mixed Methods Study Using Constructive Learning Team Model for Secondary Mathematics Teachers

    Science.gov (United States)

    Ritter, Kristy L.

    2010-01-01

    The constructive learning team model for secondary mathematics teachers (CLTM) was created to provide students with learning opportunities and experiences that address deficiencies in oral and written communication, logical processes and analysis, mathematical operations, independent learning, teamwork, and technology utilization. This study…

  20. Prototype Development of an ICT System to Support Construction Management Based on Virtual Models and RFID

    DEFF Research Database (Denmark)

    Sørensen, Kristian Birch; Christiansson, Per; Svidt, Kjeld

    2009-01-01

    early example) of an ICT system was carried out to identify and formalise user needs in relation to construction management based on virtual models and radio frequency identification (RFID). The prototype was developed to support working processes in real-time project progress management, quality...

  1. Relations between Minuchin's Structural Family Model and Kohut's Self-Psychology Constructs.

    Science.gov (United States)

    Perosa, Linda

    1996-01-01

    Examines relationship between structural family model and self-psychology constructs. College women (n=164) completed the Structural Family Interaction Scale-Revised (SFIS-R), the Parental Relations Inventory, and the Goal Instability and Superiority scales from the Self-Expression Inventory. Indicated that women raised in families with strong…

  2. Cultural, Social, and Economic Capital Constructs in International Assessments: An Evaluation Using Exploratory Structural Equation Modeling

    Science.gov (United States)

    Caro, Daniel H.; Sandoval-Hernández, Andrés; Lüdtke, Oliver

    2014-01-01

    The article employs exploratory structural equation modeling (ESEM) to evaluate constructs of economic, cultural, and social capital in international large-scale assessment (LSA) data from the Progress in International Reading Literacy Study (PIRLS) 2006 and the Programme for International Student Assessment (PISA) 2009. ESEM integrates the…

  3. Britney, Beyonce, and Me--Primary School Girls' Role Models and Constructions of the "Popular" Girl

    Science.gov (United States)

    Read, Barbara

    2011-01-01

    This paper looks at the ways in which the gendered social construction of the "popular girl" infuses girls' ideas as to their role models: those representing who they would like to be when they "grow up". It will look at the ways in which the gendered characteristics that are seen to be of most value to girls (often embodied by "celebrities" such…

  4. A construction kit for modeling the security of M-Commerce applications

    OpenAIRE

    Reif, Wolfgang

    2004-01-01

    A construction kit for modeling the security of M-Commerce applications / Dominik Haneberg, Wolfgang Reif, Kurt Stenzel. - In: Applying formal methods : testing, performance and M/E commerce ; FORTE 2004 Workshops The FormEMC ..., Toledo, Spain, October 1 - 2, 2004 ; proceedings / Manuel Núñez ... (ed.). - Berlin u. a : Springer, 2004. - S. 72-85. - (Lecture notes in computer science ; 3236)

  5. The Construction of Teaching Model on College English Writing from the Perspective of Cognitive Genre

    Science.gov (United States)

    Wenjuan, Hao; Rui, Liang

    2016-01-01

    Teaching is a spiral rising process. A complete teaching should be composed of five parts: theoretical basis, goal orientation, operating procedures, implementation conditions and assessment. On the basis of the genre knowledge, content-based approach and process approach, this text constructs the Teaching Model of College Writing Instruction, in…

  6. A conceptual model for developing KPIs for early phases of the construction process

    NARCIS (Netherlands)

    Haponava, T.; Al-Jibouri, Saad H.S.; Mawdesley, M.; Ahmed, Syed M.; Azhar, Salman; Mohamed, Sherif

    2007-01-01

    The pre-project stage in construction is where most of the decisions about project investment and development are taken. It is therefore very important to be able to control and influence the process at the very beginning of the project. This paper proposes a model for developing a set of KPIs for

  7. Gaining Modelling and Mathematical Experience by Constructing Virtual Sensory Systems in Maze-Videogames

    Science.gov (United States)

    Sacristán, Ana Isabel; Pretelín-Ricárdez, Angel

    2017-01-01

    This work is part of a research project that aims to enhance engineering students' learning of how to apply mathematics in modelling activities of real-world situations, through the construction (design and programming) of videogames. We want also for students to relate their mathematical knowledge with other disciplines (e.g., physics, computer…

  8. Evaluation of inverse modeling techniques for pinpointing water leakages at building constructions

    NARCIS (Netherlands)

    Schijndel, van A.W.M.

    2015-01-01

    The location and nature of the moisture leakages are sometimes difficult to detect. Moreover, the relation between observed inside surface moisture patterns and where the moisture enters the construction is often not clear. The objective of this paper is to investigate inverse modeling techniques as

  9. Mental model construction, not just memory, is a central component of cognitive change in psychotherapy.

    Science.gov (United States)

    von Hecker, Ulrich; McIntosh, Daniel N; Sedek, Grzegorz

    2015-01-01

    We challenge the idea that a cognitive perspective on therapeutic change concerns only memory processes. We argue that inclusion of impairments in more generative cognitive processes is necessary for complete understanding of cases such as depression. In such cases what is identified in the target article as an "integrative memory structure" is crucially supported by processes of mental model construction.

  10. Evaluating Students' Abilities to Construct Mathematical Models from Data Using Latent Class Analysis

    Science.gov (United States)

    Brandriet, Alexandra; Rupp, Charlie A.; Lazenby, Katherine; Becker, Nicole M.

    2018-01-01

    Analyzing and interpreting data is an important science practice that contributes toward the construction of models from data; yet, there is evidence that students may struggle with making meaning of data. The study reported here focused on characterizing students' approaches to analyzing rate and concentration data in the context of method of…

  11. Construction of a mouse model of factor VIII deficiency by gene targeting

    Energy Technology Data Exchange (ETDEWEB)

    Bi, L.; Lawler, A.; Gearhart, J. [Univ. of Pennsylvania School of Medicine, Philadelphia, PA (United States)] [and others

    1994-09-01

    To develop a small animal model of hemophilia A for gene therapy experiments, we set out to construct a mouse model for factor VIII deficiency by gene targeting. First, we screened a mouse liver cDNA library using a human FVIII cDNA probe. We cloned a 2.6 Kb partial mouse factor VIII cDNA which extends from 800 base pairs of the 3{prime} end of exon 14 to the 5{prime} end of exon 26. A mouse genomic library made from strain 129 was then screened to obtain genomic fragments covering the exons desired for homologous recombination. Two genomic clones were obtained, and one covering exon 15 through 22 was used for gene targeting. To make gene targeting constructs, a 5.8 Kb genomic DNA fragment covering exons 15 to 19 of the mouse FVIII gene was subcloned, and the neo expression cassette was inserted into exons 16 and 17 separately by different strategies. These two constructs were named MFVIIIC-16 and MFVIIIC-17. The constructs were linearized and transfected into strain 129 mouse ES cells by electroporation. Factor VIII gene-knockout ES cell lines were selected by G-418 and screened by genomic Southern blots. Eight exon 16 targeted cell lines and five exon 17 targeted cell lines were obtained. Three cell lines from each construct were injected into blastocysts and surgically transferred into foster mothers. Multiple chimeric mice with 70-90% hair color derived from the ES-cell genotype were seen with both constructs. Germ line transmission of the ES-cell genotype has been obtained for the MFVIIIC-16 construct, and multiple hemophilia A carrier females have been identified. Factor VIII-deficient males will be conceived soon.

  12. Application of Building Information Modeling (3D and 4D in Construction Sector in Iraq

    Directory of Open Access Journals (Sweden)

    Kadhim Raheem Erzaij

    2017-10-01

    Full Text Available Building Information Modeling (BIM is becoming a great known established collaboration process in Architecture, Engineering, and Construction (AEC industry. In various cases in many countries, potential benefits and competitive advantages have been reported. However, despite the potentials and benefits of BIM technologies, it is not applied in the construction sector in Iraq just like many other countries of the world. The purpose of this research is to understand the uses and benefits of BIM for construction projects in Iraq. This purpose has been done by establishing a framework to application of BIM and identifying the benefits of this technology that would convince stakeholders for adopting BIM in the construction sector in Iraq. Through this research, the use of this technology has been clarified by using the proposed framework (application Revit software and linking it with the MS Project and Navisworks Manage software on the case study to identify the important benefits to be the beginning to apply the Building Information Modeling technology in the construction sector in Iraq. The research results indicated that such proposed framework can greatly improve the performance of the current state of project management through improving the project quality, cost saving and time-saving.

  13. Design and construction of a large reinforced concrete containment model to be tested to failure

    International Nuclear Information System (INIS)

    Ucciferro, J.J.; Horschel, D.S.

    1987-01-01

    The US Nuclear Regulatory Commission is investigating the performance of LWR containments subjected to severe accidents. This work is being performed by the Containment Integrity Division at Sandia National Laboratories (Sandia). The latest research effort involves the testing of a 1/6-scale reinforced concrete containment model. The containment, which was designed and constructed by United Engineers and Constructors, is the largest and most complex model of its kind. The design and construction of the containment model are the subject of this paper. The objective of the containment model tests is to generate data that can be used to qualify methods for reliably predicting the response of LWR containment buildings to severe accident loads. The data recorded during testing include deformations and leakage past sealing surfaces, as well as strains and displacements of the containment shell

  14. Modeling the sustainable development of innovation in transport construction based on the communication approach

    Science.gov (United States)

    Revunova, Svetlana; Vlasenko, Vyacheslav; Bukreev, Anatoly

    2017-10-01

    The article proposes the models of innovative activity development, which is driven by the formation of “points of innovation-driven growth”. The models are based on the analysis of the current state and dynamics of innovative development of construction enterprises in the transport sector and take into account a number of essential organizational and economic changes in management. The authors substantiate implementing such development models as an organizational innovation that has a communication genesis. The use of the communication approach to the formation of “points of innovation-driven growth” allowed the authors to apply the mathematical tools of the graph theory in order to activate the innovative activity of the transport industry in the region. As a result, the authors have proposed models that allow constructing an optimal mechanism for the formation of “points of innovation-driven growth”.

  15. [Constructing 3-dimensional colorized digital dental model assisted by digital photography].

    Science.gov (United States)

    Ye, Hong-qiang; Liu, Yu-shu; Liu, Yun-song; Ning, Jing; Zhao, Yi-jiao; Zhou, Yong-sheng

    2016-02-18

    To explore a method of constructing universal 3-dimensional (3D) colorized digital dental model which can be displayed and edited in common 3D software (such as Geomagic series), in order to improve the visual effect of digital dental model in 3D software. The morphological data of teeth and gingivae were obtained by intra-oral scanning system (3Shape TRIOS), constructing 3D digital dental models. The 3D digital dental models were exported as STL files. Meanwhile, referring to the accredited photography guide of American Academy of Cosmetic Dentistry (AACD), five selected digital photographs of patients'teeth and gingivae were taken by digital single lens reflex camera (DSLR) with the same exposure parameters (except occlusal views) to capture the color data. In Geomagic Studio 2013, after STL file of 3D digital dental model being imported, digital photographs were projected on 3D digital dental model with corresponding position and angle. The junctions of different photos were carefully trimmed to get continuous and natural color transitions. Then the 3D colorized digital dental model was constructed, which was exported as OBJ file or WRP file which was a special file for software of Geomagic series. For the purpose of evaluating the visual effect of the 3D colorized digital model, a rating scale on color simulation effect in views of patients'evaluation was used. Sixteen patients were recruited and their scores on colored and non-colored digital dental models were recorded. The data were analyzed using McNemar-Bowker test in SPSS 20. Universal 3D colorized digital dental model with better color simulation was constructed based on intra-oral scanning and digital photography. For clinical application, the 3D colorized digital dental models, combined with 3D face images, were introduced into 3D smile design of aesthetic rehabilitation, which could improve the patients' cognition for the esthetic digital design and virtual prosthetic effect. Universal 3D colorized

  16. Spacecraft Charging and the Microwave Anisotropy Probe Spacecraft

    Science.gov (United States)

    Timothy, VanSant J.; Neergaard, Linda F.

    1998-01-01

    The Microwave Anisotropy Probe (MAP), a MIDEX mission built in partnership between Princeton University and the NASA Goddard Space Flight Center (GSFC), will study the cosmic microwave background. It will be inserted into a highly elliptical earth orbit for several weeks and then use a lunar gravity assist to orbit around the second Lagrangian point (L2), 1.5 million kilometers, anti-sunward from the earth. The charging environment for the phasing loops and at L2 was evaluated. There is a limited set of data for L2; the GEOTAIL spacecraft measured relatively low spacecraft potentials (approx. 50 V maximum) near L2. The main area of concern for charging on the MAP spacecraft is the well-established threat posed by the "geosynchronous region" between 6-10 Re. The launch in the autumn of 2000 will coincide with the falling of the solar maximum, a period when the likelihood of a substorm is higher than usual. The likelihood of a substorm at that time has been roughly estimated to be on the order of 20% for a typical MAP mission profile. Because of the possibility of spacecraft charging, a requirement for conductive spacecraft surfaces was established early in the program. Subsequent NASCAP/GEO analyses for the MAP spacecraft demonstrated that a significant portion of the sunlit surface (solar cell cover glass and sunshade) could have nonconductive surfaces without significantly raising differential charging. The need for conductive materials on surfaces continually in eclipse has also been reinforced by NASCAP analyses.

  17. Aqueous extracts of a Mars analogue regolith that mimics the Phoenix landing site do not inhibit spore germination or growth of model spacecraft contaminants Bacillus subtilis 168 and Bacillus pumilus SAFR-032

    Science.gov (United States)

    Nicholson, Wayne L.; McCoy, Lashelle E.; Kerney, Krystal R.; Ming, Douglas W.; Golden, D. C.; Schuerger, Andrew C.

    2012-08-01

    Because Mars is a primary target for life detection and habitability assessment missions, its exploration is also by necessity a Planetary Protection issue. The recent finding of significant levels of perchlorate (ClO4-) in regolith sampled from the Phoenix landing site raises the question of its potential biotoxicity to putative indigenous martian life, microbial forward contaminants from Earth, or future human visitors. To address this issue, an analogue regolith was constructed based on regolith chemistry data from the Phoenix landing site. A Mars Aqueous Regolith Extract (MARE) was prepared from the Phoenix analogue regolith and analyzed by ion chromatography. The MARE contained (mg/L) the cations Na+ (1411 ± 181), Mg2+ (1051 ± 160), Ca2+ (832 ± 125), and K+ (261 ± 29), and the anions SO42-(5911±993), ClO4-(5316±1767), Cl(171±25) and F- (2.0 ± 0.4). Nitrogen-containing species NO3-(773±113) and NO2-(6.9±2.3) were also present as a result of regolith preparation procedures, but their relevance to Mars is at present unknown. The MARE was tested for potential toxic effects on two model spacecraft contaminants, the spore-forming bacteria Bacillus subtilis strain 168 and Bacillus pumilus strain SAFR-032. In B. subtilis, spore germination and initial vegetative growth (up to ˜5 h) was not inhibited in a rich complex medium prepared with the MARE, but growth after 5 h was significantly suppressed in medium prepared using the MARE. Both B. subtilis and B. pumilus exhibited significantly higher rates of spore germination and growth in the MARE vs. DW with no additions (likely due to endogenous spore nutrients), but germination and growth was further stimulated by addition of glucose and a combination of buffered inorganic salts (K2HPO4, KH2PO4, (NH4)2SO4, and MgSO4). The data indicate that the aqueous environment in the regolith from the Phoenix landing site containing high levels of perchlorate does not pose a significant barrier to growth of putative

  18. An Integrated Framework for Process-Driven Model Construction in Disease Ecology and Animal Health

    Directory of Open Access Journals (Sweden)

    Rebecca Mancy

    2017-09-01

    Full Text Available Process models that focus on explicitly representing biological mechanisms are increasingly important in disease ecology and animal health research. However, the large number of process modelling approaches makes it difficult to decide which is most appropriate for a given disease system and research question. Here, we discuss different motivations for using process models and present an integrated conceptual analysis that can be used to guide the construction of infectious disease process models and comparisons between them. Our presentation complements existing work by clarifying the major differences between modelling approaches and their relationship with the biological characteristics of the epidemiological system. We first discuss distinct motivations for using process models in epidemiological research, identifying the key steps in model design and use associated with each. We then present a conceptual framework for guiding model construction and comparison, organised according to key aspects of epidemiological systems. Specifically, we discuss the number and type of disease states, whether to focus on individual hosts (e.g., cows or groups of hosts (e.g., herds or farms, how space or host connectivity affect disease transmission, whether demographic and epidemiological processes are periodic or can occur at any time, and the extent to which stochasticity is important. We use foot-and-mouth disease and bovine tuberculosis in cattle to illustrate our discussion and support explanations of cases in which different models are used to address similar problems. The framework should help those constructing models to structure their approach to modelling decisions and facilitate comparisons between models in the literature.

  19. Exploring Environmental Factors in Nursing Workplaces That Promote Psychological Resilience: Constructing a Unified Theoretical Model

    OpenAIRE

    Cusack, Lynette; Smith, Morgan; Hegney, Desley; Rees, Clare S.; Breen, Lauren J.; Witt, Regina R.; Rogers, Cath; Williams, Allison; Cross, Wendy; Cheung, Kin

    2016-01-01

    Building nurses' resilience to complex and stressful practice environments is necessary to keep skilled nurses in the workplace and ensuring safe patient care. A unified theoretical framework titled Health Services Workplace Environmental Resilience Model (HSWERM), is presented to explain the environmental factors in the workplace that promote nurses' resilience. The framework builds on a previously-published theoretical model of individual resilience, which identified the key constructs of p...

  20. Project Management Life Cycle Models to Improve Management in High-rise Construction

    Science.gov (United States)

    Burmistrov, Andrey; Siniavina, Maria; Iliashenko, Oksana

    2018-03-01

    The paper describes a possibility to improve project management in high-rise buildings construction through the use of various Project Management Life Cycle Models (PMLC models) based on traditional and agile project management approaches. Moreover, the paper describes, how the split the whole large-scale project to the "project chain" will create the factor for better manageability of the large-scale buildings project and increase the efficiency of the activities of all participants in such projects.

  1. Constructing a Computer Model of the Human Eye Based on Tissue Slice Images

    OpenAIRE

    Dai, Peishan; Wang, Boliang; Bao, Chunbo; Ju, Ying

    2010-01-01

    Computer simulation of the biomechanical and biological heat transfer in ophthalmology greatly relies on having a reliable computer model of the human eye. This paper proposes a novel method on the construction of a geometric model of the human eye based on tissue slice images. Slice images were obtained from an in vitro Chinese human eye through an embryo specimen processing methods. A level set algorithm was used to extract contour points of eye tissues while a principle component analysi...

  2. Project Management Life Cycle Models to Improve Management in High-rise Construction

    Directory of Open Access Journals (Sweden)

    Burmistrov Andrey

    2018-01-01

    Full Text Available The paper describes a possibility to improve project management in high-rise buildings construction through the use of various Project Management Life Cycle Models (PMLC models based on traditional and agile project management approaches. Moreover, the paper describes, how the split the whole large-scale project to the "project chain" will create the factor for better manageability of the large-scale buildings project and increase the efficiency of the activities of all participants in such projects.

  3. Internal Mass Motion for Spacecraft Dynamics and Control

    National Research Council Canada - National Science Library

    Hall, Christopher D

    2008-01-01

    We present a detailed description of the application of a noncanonical Hamiltonian formulation to the modeling, analysis, and simulation of the dynamics of gyrostat spacecraft with internal mass motion...

  4. Spacecraft early design validation using formal methods

    International Nuclear Information System (INIS)

    Bozzano, Marco; Cimatti, Alessandro; Katoen, Joost-Pieter; Katsaros, Panagiotis; Mokos, Konstantinos; Nguyen, Viet Yen; Noll, Thomas; Postma, Bart; Roveri, Marco

    2014-01-01

    The size and complexity of software in spacecraft is increasing exponentially, and this trend complicates its validation within the context of the overall spacecraft system. Current validation methods are labor-intensive as they rely on manual analysis, review and inspection. For future space missions, we developed – with challenging requirements from the European space industry – a novel modeling language and toolset for a (semi-)automated validation approach. Our modeling language is a dialect of AADL and enables engineers to express the system, the software, and their reliability aspects. The COMPASS toolset utilizes state-of-the-art model checking techniques, both qualitative and probabilistic, for the analysis of requirements related to functional correctness, safety, dependability and performance. Several pilot projects have been performed by industry, with two of them having focused on the system-level of a satellite platform in development. Our efforts resulted in a significant advancement of validating spacecraft designs from several perspectives, using a single integrated system model. The associated technology readiness level increased from level 1 (basic concepts and ideas) to early level 4 (laboratory-tested)

  5. Determination of Realistic Fire Scenarios in Spacecraft

    Science.gov (United States)

    Dietrich, Daniel L.; Ruff, Gary A.; Urban, David

    2013-01-01

    This paper expands on previous work that examined how large a fire a crew member could successfully survive and extinguish in the confines of a spacecraft. The hazards to the crew and equipment during an accidental fire include excessive pressure rise resulting in a catastrophic rupture of the vehicle skin, excessive temperatures that burn or incapacitate the crew (due to hyperthermia), carbon dioxide build-up or accumulation of other combustion products (e.g. carbon monoxide). The previous work introduced a simplified model that treated the fire primarily as a source of heat and combustion products and sink for oxygen prescribed (input to the model) based on terrestrial standards. The model further treated the spacecraft as a closed system with no capability to vent to the vacuum of space. The model in the present work extends this analysis to more realistically treat the pressure relief system(s) of the spacecraft, include more combustion products (e.g. HF) in the analysis and attempt to predict the fire spread and limiting fire size (based on knowledge of terrestrial fires and the known characteristics of microgravity fires) rather than prescribe them in the analysis. Including the characteristics of vehicle pressure relief systems has a dramatic mitigating effect by eliminating vehicle overpressure for all but very large fires and reducing average gas-phase temperatures.

  6. A Decision Model Assessing the Owner and Contractor’s Conflict Behaviors in Construction Projects

    Directory of Open Access Journals (Sweden)

    Guangdong Wu

    2018-01-01

    Full Text Available Considering the effects of the contractor’s conflict behaviors on the project benefit, a decision model between the owner and contractor’s conflict behaviors in construction projects was constructed using the principal-agent theory and game theory. The model was analyzed under nonconflicting and conflicting conditions, and a numerical simulation and example analysis were proposed to verify the constructed model’s conclusion. The results showed that the effort levels of the owner and contractor not only relate to benefit-sharing coefficient and effort outcome coefficient but also depend on the contractor’s ability of converting the conflict into benefit and the loss caused by conflict behaviors. A higher ability of converting conflicts into benefits and lower levels of the loss caused by conflict behaviors for the contractor lead to lower levels of the net benefit of the owner, conversely higher levels of the net benefit of the contractor. Balancing the contractor’s ability of converting conflicts into benefits and the loss caused by conflict behaviors lead to a more reasonable risk allocation between the owner and contractor, improving the effort level and net benefit. To add value to the construction project, the owner should establish an impartial and reasonable benefit-sharing mechanism, optimize the owner and contractor’s resource arrangement, maximize the positive effect of conflict on project benefits, and avoid the negative effect of conflict. Few studies to date have investigated the effects of conflict behaviors on project benefits in terms of modeling and simulation in construction projects. As such, this study bridges this gap and contributes significant theoretical and practical insights about managing conflict behaviors in an interorganizational context, thus enhancing performance in construction projects.

  7. Evaluating measurement of dynamic constructs: defining a measurement model of derivatives.

    Science.gov (United States)

    Estabrook, Ryne

    2015-03-01

    While measurement evaluation has been embraced as an important step in psychological research, evaluating measurement structures with longitudinal data is fraught with limitations. This article defines and tests a measurement model of derivatives (MMOD), which is designed to assess the measurement structure of latent constructs both for analyses of between-person differences and for the analysis of change. Simulation results indicate that MMOD outperforms existing models for multivariate analysis and provides equivalent fit to data generation models. Additional simulations show MMOD capable of detecting differences in between-person and within-person factor structures. Model features, applications, and future directions are discussed. (c) 2015 APA, all rights reserved).

  8. A Quantized State Approach to On-line Simulation for Spacecraft Autonomy

    DEFF Research Database (Denmark)

    Alminde, Lars; Stoustrup, Jakob; Bendtsen, Jan Dimon

    2006-01-01

    Future space applications will require an increased level of operational autonomy. This calls for declarative methods for spacecraft state estimation and control, so that the spacecraft engineer can focus on modeling the spacecraft rather than implementing all details of the on-line system. Celeb...

  9. Construction of tomographic head model using sectioned photographic images of cadaver

    International Nuclear Information System (INIS)

    Lee, Choon Sik; Lee, Jai Ki; Park, Jin Seo; Chung, Min Suk

    2004-01-01

    Tomographic models are currently the most complete, developed and realistic models of the human anatomy. They have been used to estimate organ doses for diagnostic radiation examination and radiotherapy treatment planning, and radiation protection. The quality of original anatomic images is a key factor to build a quality tomographic model. Computed tomography (CT) and magnetic resonance imaging (MRI) scan, from which most of current tomographic models are constructed, have their inherent shortcomings. In this study, a tomographic model of Korean adult male head was constructed by using serially sectioned photographs of cadaver. The cadaver was embedded, frozen, serially sectioned and photographed by high resolution digital camera at 0.2 mm interval. The contours of organs and tissues in photographs were segmented by several trained anatomists. The 120 segmented images of head at 2mm interval were converted into binary files and ported into Monte Carlo code to perform an example calculation of organ dose. Whole body tomographic model will be constructed by using the procedure developed in this study

  10. Construction and utilization of linear empirical core models for PWR in-core fuel management

    International Nuclear Information System (INIS)

    Okafor, K.C.

    1988-01-01

    An empirical core-model construction procedure for pressurized water reactor (PWR) in-core fuel management is developed that allows determining the optimal BOC k ∞ profiles in PWRs as a single linear-programming problem and thus facilitates the overall optimization process for in-core fuel management due to algorithmic simplification and reduction in computation time. The optimal profile is defined as one that maximizes cycle burnup. The model construction scheme treats the fuel-assembly power fractions, burnup, and leakage as state variables and BOC zone enrichments as control variables. The core model consists of linear correlations between the state and control variables that describe fuel-assembly behavior in time and space. These correlations are obtained through time-dependent two-dimensional core simulations. The core model incorporates the effects of composition changes in all the enrichment control zones on a given fuel assembly and is valid at all times during the cycle for a given range of control variables. No assumption is made on the geometry of the control zones. A scatter-composition distribution, as well as annular, can be considered for model construction. The application of the methodology to a typical PWR core indicates good agreement between the model and exact simulation results

  11. Spacecraft control center automation using the generic inferential executor (GENIE)

    Science.gov (United States)

    Hartley, Jonathan; Luczak, Ed; Stump, Doug

    1996-01-01

    The increasing requirement to dramatically reduce the cost of mission operations led to increased emphasis on automation technology. The expert system technology used at the Goddard Space Flight Center (MD) is currently being applied to the automation of spacecraft control center activities. The generic inferential executor (GENIE) is a tool which allows pass automation applications to be constructed. The pass script templates constructed encode the tasks necessary to mimic flight operations team interactions with the spacecraft during a pass. These templates can be configured with data specific to a particular pass. Animated graphical displays illustrate the progress during the pass. The first GENIE application automates passes of the solar, anomalous and magnetospheric particle explorer (SAMPEX) spacecraft.

  12. Constructive tensorial group field theory II: the {U(1)-T^4_4} model

    Science.gov (United States)

    Lahoche, Vincent

    2018-05-01

    In this paper, we continue our program of non-pertubative constructions of tensorial group field theories (TGFT). We prove analyticity and Borel summability in a suitable domain of the coupling constant of the simplest super-renormalizable TGFT which contains some ultraviolet divergencies, namely the color-symmetric quartic melonic rank-four model with Abelian gauge invariance, nicknamed . We use a multiscale loop vertex expansion. It is an extension of the loop vertex expansion (the basic constructive technique for non-local theories) which is required for theories that involve non-trivial renormalization.

  13. Construction of a voxel model from CT images with density derived from CT numbers

    International Nuclear Information System (INIS)

    Cheng Mengyun; Zeng Qin; Cao Ruifen; Li Gui; Zheng Huaqing; Huang Shanqing; Song Gang; Wu Yican

    2010-01-01

    The voxel models representing human anatomy have been developed to calculate dose distribution in human body, while the density is the most important physical property of voxel model. Traditionally, when creating the Monte Carlo input files, the average tissue parameters recommended in ICRP report were used to assign each voxel in the existing voxel models. However, as each tissue consists of many voxels in which voxels are different in their densities, the method of assigning average tissue parameters doesn't take account of the voxel's discrepancy, and can't represent human anatomy faithfully. To represent human anatomy more faithfully, a method was implemented to assign each voxel, the density of which was derived from CT number. In order to compare with the traditional method, we have constructed two models from a same cadaver specimen date set. A CT-based pelvic voxel model called Pelvis-CT model, was constructed, the densities of which were derived from the CT numbers. A color photograph-based pelvic voxel model called Pelvis-Photo model, was also constructed, the densities of which were taken from ICRP Publication. The CT images and color photographs were obtained from the same female cadaver specimen. The Pelvis-CT and Pelvis-Photo models were ported into Monte Carlo code MCNP to calculate the conversion coefficients from kerma free-in-air to absorbed dose for external monoenergetic photon beams with energies of 0.1, 1 and 10 MeV under anterior-posterior (AP) geometries. The results were compared with those of given in ICRP74. Differences of up to 50% were observed between conversion coefficients of Pelvis-CT and Pelvis-Photo models, moreover the discrepancies decreased for the photon beams with higher energies. The overall trend of conversion coefficients of the Pelvis-CT model were agreed well with that of ICRP74 data. (author)

  14. Construction of a voxel model from CT images with density derived from CT numbers

    International Nuclear Information System (INIS)

    Cheng Mengyun; Zeng Qin; Cao Ruifen; Li Gui; Zheng Huaqing; Huang Shanqing; Song Gang; Wu Yican

    2011-01-01

    The voxel models representing human anatomy have been developed to calculate dose distribution in human body, while the density and elemental composition are the most important physical properties of voxel model. Usually, when creating the Monte Carlo input files, the average tissue densities recommended in ICRP Publication were used to assign each voxel in the existing voxel models. As each tissue consists of many voxels with different densities, the conventional method of average tissue densities failed to take account of the voxel's discrepancy, and therefore could not represent human anatomy faithfully. To represent human anatomy more faithfully, a method was implemented to assign each voxel, the densities of which were derived from CT number. In order to compare with the traditional method, we constructed two models from the cadaver specimen dataset. A CT-based pelvic voxel model called Pelvis-CT model was constructed, the densities of which were derived from the CT numbers. A color photograph-based pelvic voxel model called Pelvis-Photo model was also constructed, the densities of which were taken from ICRP Publication. The CT images and the color photographs were obtained from the same female cadaver specimen. The Pelvis-CT and Pelvis-Photo models were both ported into Monte Carlo code MCNP to calculate the conversion coefficients from kerma free-in-air to absorbed dose for external monoenergetic photon beams with energies of 0.1, 1 and 10 MeV under anterior-posterior (AP) geometry. The results were compared with those of given in ICRP Publication 74. Differences of up to 50% were observed between conversion coefficients of Pelvis-CT and Pelvis- Photo models, moreover the discrepancies decreased for the photon beams with higher energies. The overall trend of conversion coefficients of the Pelvis-CT model agreed well with that of ICRP Publication 74 data. (author)

  15. Spacecraft Environmental Interactions Technology, 1983

    Science.gov (United States)

    1985-01-01

    State of the art of environment interactions dealing with low-Earth-orbit plasmas; high-voltage systems; spacecraft charging; materials effects; and direction of future programs are contained in over 50 papers.

  16. Gravity Probe B spacecraft description

    International Nuclear Information System (INIS)

    Bennett, Norman R; Burns, Kevin; Katz, Russell; Kirschenbaum, Jon; Mason, Gary; Shehata, Shawky

    2015-01-01

    The Gravity Probe B spacecraft, developed, integrated, and tested by Lockheed Missiles and Space Company and later Lockheed Martin Corporation, consisted of structures, mechanisms, command and data handling, attitude and translation control, electrical power, thermal control, flight software, and communications. When integrated with the payload elements, the integrated system became the space vehicle. Key requirements shaping the design of the spacecraft were: (1) the tight mission timeline (17 months, 9 days of on-orbit operation), (2) precise attitude and translational control, (3) thermal protection of science hardware, (4) minimizing aerodynamic, magnetic, and eddy current effects, and (5) the need to provide a robust, low risk spacecraft. The spacecraft met all mission requirements, as demonstrated by dewar lifetime meeting specification, positive power and thermal margins, precision attitude control and drag-free performance, reliable communications, and the collection of more than 97% of the available science data. (paper)

  17. A Bayesian method for construction of Markov models to describe dynamics on various time-scales.

    Science.gov (United States)

    Rains, Emily K; Andersen, Hans C

    2010-10-14

    The dynamics of many biological processes of interest, such as the folding of a protein, are slow and complicated enough that a single molecular dynamics simulation trajectory of the entire process is difficult to obtain in any reasonable amount of time. Moreover, one such simulation may not be sufficient to develop an understanding of the mechanism of the process, and multiple simulations may be necessary. One approach to circumvent this computational barrier is the use of Markov state models. These models are useful because they can be constructed using data from a large number of shorter simulations instead of a single long simulation. This paper presents a new Bayesian method for the construction of Markov models from simulation data. A Markov model is specified by (τ,P,T), where τ is the mesoscopic time step, P is a partition of configuration space into mesostates, and T is an N(P)×N(P) transition rate matrix for transitions between the mesostates in one mesoscopic time step, where N(P) is the number of mesostates in P. The method presented here is different from previous Bayesian methods in several ways. (1) The method uses Bayesian analysis to determine the partition as well as the transition probabilities. (2) The method allows the construction of a Markov model for any chosen mesoscopic time-scale τ. (3) It constructs Markov models for which the diagonal elements of T are all equal to or greater than 0.5. Such a model will be called a "consistent mesoscopic Markov model" (CMMM). Such models have important advantages for providing an understanding of the dynamics on a mesoscopic time-scale. The Bayesian method uses simulation data to find a posterior probability distribution for (P,T) for any chosen τ. This distribution can be regarded as the Bayesian probability that the kinetics observed in the atomistic simulation data on the mesoscopic time-scale τ was generated by the CMMM specified by (P,T). An optimization algorithm is used to find the most

  18. Construction Process Simulation and Safety Analysis Based on Building Information Model and 4D Technology

    Institute of Scientific and Technical Information of China (English)

    HU Zhenzhong; ZHANG Jianping; DENG Ziyin

    2008-01-01

    Time-dependent structure analysis theory has been proved to be more accurate and reliable com-pared to commonly used methods during construction. However, so far applications are limited to partial pe-riod and part of the structure because of immeasurable artificial intervention. Based on the building informa-tion model (BIM) and four-dimensional (4D) technology, this paper proposes an improves structure analysis method, which can generate structural geometry, resistance model, and loading conditions automatically by a close interlink of the schedule information, architectural model, and material properties. The method was applied to a safety analysis during a continuous and dynamic simulation of the entire construction process.The results show that the organic combination of the BIM, 4D technology, construction simulation, and safety analysis of time-dependent structures is feasible and practical. This research also lays a foundation for further researches on building lifecycle management by combining architectural design, structure analy-sis, and construction management.

  19. Applying total interpretive structural modeling to study factors affecting construction labour productivity

    Directory of Open Access Journals (Sweden)

    Sayali Shrikrishna Sandbhor

    2014-03-01

    Full Text Available Construction sector has always been dependent on manpower. Most of the activities carried out on any construction site are labour intensive. Since productivity of any project depends directly on productivity of labour, it is a prime responsibility of the employer to enhance labour productivity. Measures to improve the same depend on analysis of positive and negative factors affecting productivity. Major attention should be given to factors that decrease the productivity of labour. Factor analysis thus is an integral part of any study aiming to improve productivity.  Interpretive structural modeling is a methodology for identifying and summarizing relationships among factors which define an issue or problem. It provides a means to arrange the factors in an order as per their complexity. This study attempts to use the latest version of interpretive structural modeling i.e. total interpretive structural modeling to analyze factors negatively affecting construction labour productivity. It establishes interpretive relationship among these factors facilitating improvement in the overall productivity of construction site.

  20. A mathematical model for fluid shear-sensitive 3D tissue construct development.

    Science.gov (United States)

    Liu, Dan; Chua, Chee-Kai; Leong, Kah-Fai

    2013-01-01

    This research studies dynamic culture for 3D tissue construct development with computational fluid dynamics. It proposes a mathematical model to evaluate the impact of flow rates and flow shear stress on cell growth in 3D constructs under perfusion. The modeling results show that dynamic flow, even at flow rate as low as 0.002 cm/s, can support much better mass exchange, higher cell number, and more even cell and nutrient distribution compared to static culture. Higher flow rate can further improve nutrient supply and mass exchange in the construct, promoting better nutritious environment and cell proliferation compared to lower flow rate. In addition, consideration of flow shear stress predicts much higher cell number in the construct compared to that without shear consideration. While the nutrient can dominate shear stress in influencing cell proliferation, the shear effect increases with flow rate. The proposed model helps tissue engineers better understand the cell-flow relationship at the molecular level during dynamic culture.

  1. Quantifying and modeling soil erosion and sediment export from construction sites in southern California

    Science.gov (United States)

    Wernet, A. K.; Beighley, R. E.

    2006-12-01

    Soil erosion is a power process that continuously alters the Earth's landscape. Human activities, such as construction and agricultural practices, and natural events, such as forest fires and landslides, disturb the landscape and intensify erosion processes leading to sudden increases in runoff sediment concentrations and degraded stream water quality. Understanding soil erosion and sediment transport processes is of great importance to researchers and practicing engineers, who routinely use models to predict soil erosion and sediment movement for varied land use and climate change scenarios. However, existing erosion models are limited in their applicability to constructions sites which have highly variable soil conditions (density, moisture, surface roughness, and best management practices) that change often in both space and time. The goal of this research is to improve the understanding, predictive capabilities and integration of treatment methodologies for controlling soil erosion and sediment export from construction sites. This research combines modeling with field monitoring and laboratory experiments to quantify: (a) spatial and temporal distribution of soil conditions on construction sites, (b) soil erosion due to event rainfall, and (c) potential offsite discharge of sediment with and without treatment practices. Field sites in southern California were selected to monitor the effects of common construction activities (ex., cut/fill, grading, foundations, roads) on soil conditions and sediment discharge. Laboratory experiments were performed in the Soil Erosion Research Laboratory (SERL), part of the Civil and Environmental Engineering department at San Diego State University, to quantify the impact of individual factors leading to sediment export. SERL experiments utilize a 3-m by 10-m tilting soil bed with soil depths up to 1 m, slopes ranging from 0 to 50 percent, and rainfall rates up to 150 mm/hr (6 in/hr). Preliminary modeling, field and laboratory

  2. Construction of a three-dimensional interactive model of the skull base and cranial nerves.

    Science.gov (United States)

    Kakizawa, Yukinari; Hongo, Kazuhiro; Rhoton, Albert L

    2007-05-01

    The goal was to develop an interactive three-dimensional (3-D) computerized anatomic model of the skull base for teaching microneurosurgical anatomy and for operative planning. The 3-D model was constructed using commercially available software (Maya 6.0 Unlimited; Alias Systems Corp., Delaware, MD), a personal computer, four cranial specimens, and six dry bones. Photographs from at least two angles of the superior and lateral views were imported to the 3-D software. Many photographs were needed to produce the model in anatomically complex areas. Careful dissection was needed to expose important structures in the two views. Landmarks, including foramen, bone, and dura mater, were used as reference points. The 3-D model of the skull base and related structures was constructed using more than 300,000 remodeled polygons. The model can be viewed from any angle. It can be rotated 360 degrees in any plane using any structure as the focal point of rotation. The model can be reduced or enlarged using the zoom function. Variable transparencies could be assigned to any structures so that the structures at any level can be seen. Anatomic labels can be attached to the structures in the 3-D model for educational purposes. This computer-generated 3-D model can be observed and studied repeatedly without the time limitations and stresses imposed by surgery. This model may offer the potential to create interactive surgical exercises useful in evaluating multiple surgical routes to specific target areas in the skull base.

  3. An Estimation of Construction and Demolition Debris in Seoul, Korea: Waste Amount, Type, and Estimating Model.

    Science.gov (United States)

    Seo, Seongwon; Hwang, Yongwoo

    1999-08-01

    Construction and demolition (C&D) debris is generated at the site of various construction activities. However, the amount of the debris is usually so large that it is necessary to estimate the amount of C&D debris as accurately as possible for effective waste management and control in urban areas. In this paper, an effective estimation method using a statistical model was proposed. The estimation process was composed of five steps: estimation of the life span of buildings; estimation of the floor area of buildings to be constructed and demolished; calculation of individual intensity units of C&D debris; and estimation of the future C&D debris production. This method was also applied in the city of Seoul as an actual case, and the estimated amount of C&D debris in Seoul in 2021 was approximately 24 million tons. Of this total amount, 98% was generated by demolition, and the main components of debris were concrete and brick.

  4. Origami rules for the construction of localized eigenstates of the Hubbard model in decorated lattices

    Science.gov (United States)

    Dias, R. G.; Gouveia, J. D.

    2015-11-01

    We present a method of construction of exact localized many-body eigenstates of the Hubbard model in decorated lattices, both for U = 0 and U → ∞. These states are localized in what concerns both hole and particle movement. The starting point of the method is the construction of a plaquette or a set of plaquettes with a higher symmetry than that of the whole lattice. Using a simple set of rules, the tight-binding localized state in such a plaquette can be divided, folded and unfolded to new plaquette geometries. This set of rules is also valid for the construction of a localized state for one hole in the U → ∞ limit of the same plaquette, assuming a spin configuration which is a uniform linear combination of all possible permutations of the set of spins in the plaquette.

  5. Precursor models construction at preschool education: an approach to improve scientific education in the classroom

    Directory of Open Access Journals (Sweden)

    SABRINA PATRICIA CANEDO- IBARRA

    2010-07-01

    Full Text Available This study aimed to explore young children scientific precursor models construction and how the designed teaching strategy was successful for improving science learning at preschool in a social context. We describe how 6 years old children built a precursor model of flotation based on density. The exploratory study used a qualitative data collection and analysis following a pre-interview, instructional process and post-interview design. On analyzing children’s answers after the instructional period, we realized that several children were led to both the construction of a precursor model and a general qualitative upgrade in reasoning. We conclude that learning activities were effective and that the approach used in this study may help expand and improve teaching and learning of scientific concepts in preschool education

  6. Construct validity of the ovine model in endoscopic sinus surgery training.

    Science.gov (United States)

    Awad, Zaid; Taghi, Ali; Sethukumar, Priya; Tolley, Neil S

    2015-03-01

    To demonstrate construct validity of the ovine model as a tool for training in endoscopic sinus surgery (ESS). Prospective, cross-sectional evaluation study. Over 18 consecutive months, trainees and experts were evaluated in their ability to perform a range of tasks (based on previous face validation and descriptive studies conducted by the same group) relating to ESS on the sheep-head model. Anonymized randomized video recordings of the above were assessed by two independent and blinded assessors. A validated assessment tool utilizing a five-point Likert scale was employed. Construct validity was calculated by comparing scores across training levels and experts using mean and interquartile range of global and task-specific scores. Subgroup analysis of the intermediate group ascertained previous experience. Nonparametric descriptive statistics were used, and analysis was carried out using SPSS version 21 (IBM, Armonk, NY). Reliability of the assessment tool was confirmed. The model discriminated well between different levels of expertise in global and task-specific scores. A positive correlation was noted between year in training and both global and task-specific scores (P variable, and the number of ESS procedures performed under supervision had the highest impact on performance. This study describes an alternative model for ESS training and assessment. It is also the first to demonstrate construct validity of the sheep-head model for ESS training. © 2014 The American Laryngological, Rhinological and Otological Society, Inc.

  7. Planning the amount of construction work by modelling the industry competitive field

    Directory of Open Access Journals (Sweden)

    Panteleeva Margarita

    2017-01-01

    Full Text Available The article gives the author’s interpretation of concepts such as the model of competitive field and competitive market conditions in the field, and shows how to quantify the competitive field provided adequate statistical base for the operation of enterprises in market competition. The authors offer a competitively construction company with a model of the competitive field, which gives the following definition: a model of a competitive field is a graph crossing function of the life cycle of concrete products construction companies. However, the model cannot afford to manage the process, it only helps to visualize the situation. To control you need to select a specific element of the model, which can be quantified. The authors make it through the competitive field, which is defined as a closed path created by the intersection of functions depending on the market price of the construction product by product positioning in the market of the time. For a quantitative analysis of the competitive field size must use the main economic-mathematical methods and types of statistical analysis of competition.

  8. Evaluation of kriging based surrogate models constructed from mesoscale computations of shock interaction with particles

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Oishik, E-mail: oishik-sen@uiowa.edu [Mechanical and Industrial Engineering, The University of Iowa, Iowa City, IA 52242 (United States); Gaul, Nicholas J., E-mail: nicholas-gaul@ramdosolutions.com [RAMDO Solutions, LLC, Iowa City, IA 52240 (United States); Choi, K.K., E-mail: kyung-choi@uiowa.edu [Mechanical and Industrial Engineering, The University of Iowa, Iowa City, IA 52242 (United States); Jacobs, Gustaaf, E-mail: gjacobs@sdsu.edu [Aerospace Engineering, San Diego State University, San Diego, CA 92115 (United States); Udaykumar, H.S., E-mail: hs-kumar@uiowa.edu [Mechanical and Industrial Engineering, The University of Iowa, Iowa City, IA 52242 (United States)

    2017-05-01

    Macro-scale computations of shocked particulate flows require closure laws that model the exchange of momentum/energy between the fluid and particle phases. Closure laws are constructed in this work in the form of surrogate models derived from highly resolved mesoscale computations of shock-particle interactions. The mesoscale computations are performed to calculate the drag force on a cluster of particles for different values of Mach Number and particle volume fraction. Two Kriging-based methods, viz. the Dynamic Kriging Method (DKG) and the Modified Bayesian Kriging Method (MBKG) are evaluated for their ability to construct surrogate models with sparse data; i.e. using the least number of mesoscale simulations. It is shown that if the input data is noise-free, the DKG method converges monotonically; convergence is less robust in the presence of noise. The MBKG method converges monotonically even with noisy input data and is therefore more suitable for surrogate model construction from numerical experiments. This work is the first step towards a full multiscale modeling of interaction of shocked particle laden flows.

  9. Construction of Korean male tomographic model segmented from PET-CT data

    International Nuclear Information System (INIS)

    Lee, Choon Sik; Park, Sang Kyun; Lee, Jai Ki

    2004-01-01

    Tomographic human models provide currently the most realistic representation of human anatomy for radiation dosimetry calculation. Most of the models have been constructed by using computed tomographic (CT) or magnetic resonance (MR) images obtained from a single individual. Each scan has its inherent advantages and disadvantages. CT scan gives a considerable radiation dose to a subject, and MR scan takes too long time to get clear images of an immobile subject. An emerging source of medical images for the construction of tomographic models is PET-CT, which is performed when looking for cancer. In this study, a tomographic model of Korean adult male was developed by processing whole-body CT images of a PET-CT-scanned healthy volunteer. The 343 slices of the CT images were semi-automatically segmented layer by layer using a graphic software and screen digitizer. The 3rd Korean tomographic model, named KRMAN-2, consisting of 300x150x344 voxels of a size of 2x2x5mm 3 , was constructed. Examples of application to Monte Carlo radiation dosimetry calculation in idealized whole-body irradiations were given and discussed

  10. [A competency model of rural general practitioners: theory construction and empirical study].

    Science.gov (United States)

    Yang, Xiu-Mu; Qi, Yu-Long; Shne, Zheng-Fu; Han, Bu-Xin; Meng, Bei

    2015-04-01

    To perform theory construction and empirical study of the competency model of rural general practitioners. Through literature study, job analysis, interviews, and expert team discussion, the questionnaire of rural general practitioners competency was constructed. A total of 1458 rural general practitioners were surveyed by the questionnaire in 6 central provinces. The common factors were constructed using the principal component method of exploratory factor analysis and confirmatory factor analysis. The influence of the competency characteristics on the working performance was analyzed using regression equation analysis. The Cronbach 's alpha coefficient of the questionnaire was 0.974. The model consisted of 9 dimensions and 59 items. The 9 competency dimensions included basic public health service ability, basic clinical skills, system analysis capability, information management capability, communication and cooperation ability, occupational moral ability, non-medical professional knowledge, personal traits and psychological adaptability. The rate of explained cumulative total variance was 76.855%. The model fitting index were Χ(2)/df 1.88, GFI=0.94, NFI=0.96, NNFI=0.98, PNFI=0.91, RMSEA=0.068, CFI=0.97, IFI=0.97, RFI=0.96, suggesting good model fitting. Regression analysis showed that the competency characteristics had a significant effect on job performance. The rural general practitioners competency model provides reference for rural doctor training, rural order directional cultivation of medical students, and competency performance management of the rural general practitioners.

  11. Construction and Experimental Implementation of a Model-Based Inverse Filter to Attenuate Hysteresis in Ferroelectric Transducers

    National Research Council Canada - National Science Library

    Hatch, Andrew G; Smith, Ralph C; De, Tathagata; Salapaka, Murti V

    2005-01-01

    .... In this paper, we illustrate the construction of inverse filters, based on homogenized energy models, which can be used to approximately linearize the piezoceramic transducer behavior for linear...

  12. The interaction of a flowing plasma with a dipole magnetic field: measurements and modelling of a diamagnetic cavity relevant to spacecraft protection

    International Nuclear Information System (INIS)

    Bamford, R; Bradford, J; Bingham, R; Gargate, L; Hapgood, M; Stamper, R; Gibson, K J; Thornton, A J; Silva, L O; Fonseca, R A; Norberg, C; Todd, T

    2008-01-01

    Here we describe a new experiment to test the shielding concept of a dipole-like magnetic field and plasma, surrounding a spacecraft forming a 'mini magnetosphere'. Initial laboratory experiments have been conducted to determine the effectiveness of a magnetized plasma barrier to be able to expel an impacting, low beta, supersonic flowing energetic plasma representing the solar wind. Optical and Langmuir probe data of the plasma density, the plasma flow velocity and the intensity of the dipole field clearly show the creation of a narrow transport barrier region and diamagnetic cavity virtually devoid of energetic plasma particles. This demonstrates the potential viability of being able to create a small 'hole' in a solar wind plasma, of the order of the ion Larmor orbit width, in which an inhabited spacecraft could reside in relative safety. The experimental results have been quantitatively compared with a 3D particle-in-cell 'hybrid' code simulation that uses kinetic ions and fluid electrons, showing good qualitative agreement and excellent quantitative agreement. Together the results demonstrate the pivotal role of particle kinetics in determining generic plasma transport barriers.

  13. Construction cost prediction model for conventional and sustainable college buildings in North America

    Directory of Open Access Journals (Sweden)

    Othman Subhi Alshamrani

    2017-03-01

    Full Text Available The literature lacks in initial cost prediction models for college buildings, especially comparing costs of sustainable and conventional buildings. A multi-regression model was developed for conceptual initial cost estimation of conventional and sustainable college buildings in North America. RS Means was used to estimate the national average of construction costs for 2014, which was subsequently utilized to develop the model. The model could predict the initial cost per square feet with two structure types made of steel and concrete. The other predictor variables were building area, number of floors and floor height. The model was developed in three major stages, such as preliminary diagnostics on data quality, model development and validation. The developed model was successfully tested and validated with real-time data.

  14. Mathematical modelling of the process of quality control of construction products

    Directory of Open Access Journals (Sweden)

    Pogorelov Vadim

    2017-01-01

    Full Text Available The study presents the results of years of research in the field of quality management of industrial production construction production, based on mathematical modelling techniques, process and results of implementing the developed programme of monitoring and quality control in the production process of the enterprise. The aim of this work is the presentation of scientific community of the practical results of mathematical modelling in application programs. In the course of the research addressed the description of the applied mathematical models, views, practical results of its application in the applied field to assess quality control. The authors used this mathematical model in practice. The article presents the results of applying this model. The authors developed the experimental software management and quality assessment by using mathematical modeling methods. The authors continue research in this direction to improve the diagnostic systems and quality management systems based on mathematical modeling methods prognostic and diagnostic processes.

  15. Supersymmetric extensions of Calogero-Moser-Sutherland-like models: construction and some solutions

    International Nuclear Information System (INIS)

    Kohler, Heiner; Guhr, Thomas

    2005-01-01

    We introduce a new class of models for interacting particles. Our construction is based on Jacobians for the radial coordinates on certain superspaces. The resulting models contain two parameters determining the strengths of the interactions. This extends and generalizes the models of the Calogero-Moser-Sutherland type for interacting particles in ordinary spaces. The latter ones are included in our models as special cases. Using results which we obtained previously for spherical functions in superspaces, we obtain various properties and some explicit forms for the solutions. We present physical interpretations. Our models involve two kinds of interacting particles. One of the models can be viewed as describing interacting electrons in a lower and upper band of a quasi-one-dimensional semiconductor. Another model is quasi-two-dimensional. Two kinds of particles are confined to two different spatial directions, the interaction contains dipole-dipole or tensor forces

  16. Constructing an Efficient Self-Tuning Aircraft Engine Model for Control and Health Management Applications

    Science.gov (United States)

    Armstrong, Jeffrey B.; Simon, Donald L.

    2012-01-01

    Self-tuning aircraft engine models can be applied for control and health management applications. The self-tuning feature of these models minimizes the mismatch between any given engine and the underlying engineering model describing an engine family. This paper provides details of the construction of a self-tuning engine model centered on a piecewise linear Kalman filter design. Starting from a nonlinear transient aerothermal model, a piecewise linear representation is first extracted. The linearization procedure creates a database of trim vectors and state-space matrices that are subsequently scheduled for interpolation based on engine operating point. A series of steady-state Kalman gains can next be constructed from a reduced-order form of the piecewise linear model. Reduction of the piecewise linear model to an observable dimension with respect to available sensed engine measurements can be achieved using either a subset or an optimal linear combination of "health" parameters, which describe engine performance. The resulting piecewise linear Kalman filter is then implemented for faster-than-real-time processing of sensed engine measurements, generating outputs appropriate for trending engine performance, estimating both measured and unmeasured parameters for control purposes, and performing on-board gas-path fault diagnostics. Computational efficiency is achieved by designing multidimensional interpolation algorithms that exploit the shared scheduling of multiple trim vectors and system matrices. An example application illustrates the accuracy of a self-tuning piecewise linear Kalman filter model when applied to a nonlinear turbofan engine simulation. Additional discussions focus on the issue of transient response accuracy and the advantages of a piecewise linear Kalman filter in the context of validation and verification. The techniques described provide a framework for constructing efficient self-tuning aircraft engine models from complex nonlinear

  17. Integrating building information modeling and health and safety for onsite construction.

    Science.gov (United States)

    Ganah, Abdulkadir; John, Godfaurd A

    2015-03-01

    Health and safety (H&S) on a construction site can either make or break a contractor, if not properly managed. The usage of Building Information Modeling (BIM) for H&S on construction execution has the potential to augment practitioner understanding of their sites, and by so doing reduce the probability of accidents. This research explores BIM usage within the construction industry in relation to H&S communication. In addition to an extensive literature review, a questionnaire survey was conducted to gather information on the embedment of H&S planning with the BIM environment for site practitioners. The analysis of responses indicated that BIM will enhance the current approach of H&S planning for construction site personnel. From the survey, toolbox talk will have to be integrated with the BIM environment, because it is the predominantly used procedure for enhancing H&S issues within construction sites. The advantage is that personnel can visually understand H&S issues as work progresses during the toolbox talk onsite.

  18. CONSTRUCTION OF MECHANICAL MODEL OF THE DIESEL-TRAIN DTKR-2 CAR AND ITS FEATURES

    Directory of Open Access Journals (Sweden)

    A. Y. Kuzyshyn

    2017-12-01

    Full Text Available Purpose.The article is aimed to construct the mechanical model of the diesel train DTKr-2 of the Kryukivsk Railway Car Building Works based on the analysis of undercarriage construction. This model will be used in the study of dynamic properties of the vehicle. When constructing the model the design features and its loading methods should be displayed as much as possible. Methodology. When constructing the mechanical model of the diesel train DTKr-2 car, the pneumatic spring, which is the main element of the central spring suspension, was modeled using Kelvin-Voigt node. This node includes elastic and viscous element. Hydraulic shock absorbers that are used both in the central and axle-box spring suspension were modeled as a viscous element. During research, the rigidity of the pneumatic spring, which is associated with the change in its effective area under deformation, was assumed to be zero. Findings. This article analyzed the design of car undercarriage of the diesel train DTKr-2. The mathematical models of its main units were presented, namely, in the central spring suspension – the model of pneumatic spring. Taking into account the peculiarities of design of the diesel train DTKr-2 undercarriage it was developed its mechanical model, which will be used in the future when studying dynamic properties. Originality.For the first time for the diesel train DTKr-2 car it was developed its mechanical model taking into account the features of the interaction of individual elements of its design. It has been proposed as a pneumatic spring to use the Kelvin-Voigt node, which includes parallel arranged elastic and viscous elements. Practical value. On the basis of the proposed mechanical model, a system of ordinary differential equations of car undercarriage movement of the diesel train DTKr-2 (mathematical model will be compiled. This model is further planned to be used when studying dynamic interaction of the diesel train car undercarriage wheel

  19. Making the error-controlling algorithm of observable operator models constructive.

    Science.gov (United States)

    Zhao, Ming-Jie; Jaeger, Herbert; Thon, Michael

    2009-12-01

    Observable operator models (OOMs) are a class of models for stochastic processes that properly subsumes the class that can be modeled by finite-dimensional hidden Markov models (HMMs). One of the main advantages of OOMs over HMMs is that they admit asymptotically correct learning algorithms. A series of learning algorithms has been developed, with increasing computational and statistical efficiency, whose recent culmination was the error-controlling (EC) algorithm developed by the first author. The EC algorithm is an iterative, asymptotically correct algorithm that yields (and minimizes) an assured upper bound on the modeling error. The run time is faster by at least one order of magnitude than EM-based HMM learning algorithms and yields significantly more accurate models than the latter. Here we present a significant improvement of the EC algorithm: the constructive error-controlling (CEC) algorithm. CEC inherits from EC the main idea of minimizing an upper bound on the modeling error but is constructive where EC needs iterations. As a consequence, we obtain further gains in learning speed without loss in modeling accuracy.

  20. [Construction of the addiction prevention core competency model for preventing addictive behavior in adolescents].

    Science.gov (United States)

    Park, Hyun Sook; Jung, Sun Young

    2013-12-01

    This study was done to provide fundamental data for the development of competency reinforcement programs to prevent addictive behavior in adolescents through the construction and examination of an addiction prevention core competency model. In this study core competencies for preventing addictive behavior in adolescents through competency modeling were identified, and the addiction prevention core competency model was developed. It was validated methodologically. Competencies for preventing addictive behavior in adolescents as defined by the addiction prevention core competency model are as follows: positive self-worth, self-control skill, time management skill, reality perception skill, risk coping skill, and positive communication with parents and with peers or social group. After construction, concurrent cross validation of the addiction prevention core competency model showed that this model was appropriate. The study results indicate that the addiction prevention core competency model for the prevention of addictive behavior in adolescents through competency modeling can be used as a foundation for an integral approach to enhance adolescent is used as an adjective and prevent addictive behavior. This approach can be a school-centered, cost-efficient strategy which not only reduces addictive behavior in adolescents, but also improves the quality of their resources.

  1. On The Construction of Models for Electrical Conduction in Biological Tissues

    International Nuclear Information System (INIS)

    Gomez-Aguilar, F.; Bernal-Alvarado, J.; Cordova-Fraga, T.; Rosales-Garcia, J.; Guia-Calderon, M.

    2010-01-01

    Applying RC circuit theory, a theoretical representation for the electrical conduction in a biological multilayer system was developed. In particular an equivalent circuit for the epidermis, dermis and the subcutaneous tissue was constructed. This model includes an equivalent circuit, inside the dermis, in order to model a small formation like tumor. This work shows the feasibility to apply superficial electrodes to detect subcutaneous abnormalities. The behavior of the model is shown in the form of a frequency response chart. The Bode and Nyquist plots are also obtained. This theoretical frame is proposed to be a general treatment to describe the bioelectrical transport in a three layer bioelectrical system.

  2. Constructing Markov State Models to elucidate the functional conformational changes of complex biomolecules

    KAUST Repository

    Wang, Wei

    2017-10-06

    The function of complex biomolecular machines relies heavily on their conformational changes. Investigating these functional conformational changes is therefore essential for understanding the corresponding biological processes and promoting bioengineering applications and rational drug design. Constructing Markov State Models (MSMs) based on large-scale molecular dynamics simulations has emerged as a powerful approach to model functional conformational changes of the biomolecular system with sufficient resolution in both time and space. However, the rapid development of theory and algorithms for constructing MSMs has made it difficult for nonexperts to understand and apply the MSM framework, necessitating a comprehensive guidance toward its theory and practical usage. In this study, we introduce the MSM theory of conformational dynamics based on the projection operator scheme. We further propose a general protocol of constructing MSM to investigate functional conformational changes, which integrates the state-of-the-art techniques for building and optimizing initial pathways, performing adaptive sampling and constructing MSMs. We anticipate this protocol to be widely applied and useful in guiding nonexperts to study the functional conformational changes of large biomolecular systems via the MSM framework. We also discuss the current limitations of MSMs and some alternative methods to alleviate them.

  3. An Algorithm for Modelling the Impact of the Judicial Conflict-Resolution Process on Construction Investment

    Directory of Open Access Journals (Sweden)

    Andrej Bugajev

    2018-01-01

    Full Text Available In this article, the modelling of the judicial conflict-resolution process is considered from a construction investor’s point of view. Such modelling is important for improving the risk management for construction investors and supporting sustainable city development by supporting the development of rules regulating the construction process. Thus, this raises the problem of evaluation of different decisions and selection of the optimal one followed by distribution extraction. First, the example of such a process is analysed and schematically represented. Then, it is formalised as a graph, which is described in the form of a decision graph with cycles. We use some natural problem properties and provide the algorithm to convert this graph into a tree. Then, we propose the algorithm to evaluate profits for different scenarios with estimation of time, which is done by integration of an average daily costs function. Afterwards, the optimisation problem is solved and the optimal investor strategy is obtained—this allows one to extract the construction project profit distribution, which can be used for further analysis by standard risk (and other important information-evaluation techniques. The overall algorithm complexity is analysed, the computational experiment is performed and conclusions are formulated.

  4. CAD CONSTRUCTION METHOD OF 3D BUILDING MODELS FOR GIS ANALYSIS

    Directory of Open Access Journals (Sweden)

    P. Boguslawski

    2012-07-01

    Full Text Available Buildings are often modelled as two-dimensional (2D footprints which are extruded to simple cubes. Buildings are also represented as more complex objects with roofs, facades, etc. – in this case they are polyhedra, sometimes of a complex shape. These allow for visualisation and analysis of a wide area like a city, but micro-scale analysis of interiors is not possible. An example can be rescue operation simulation where information about the internal structure of a building and the external terrain is crucial to improve the response time. It demands a three-dimensional (3D model where each room is represented as a separate element; there are also doors, windows, walls and other objects that have to be included. Even complex geometrical models can be easily constructed using Computer-Aided Design (CAD systems. However, lack of semantic information and topological relations makes such models poor choices for GIS analysis. With the new dual half-edge (DHE data structure and a set of Euler operators a 3D model can be built as in CAD systems, and represented as a cell complex. Construction of non-manifold objects is also possible. An advantage of the DHE is simplicity – only edges and nodes are used. Because of the 3D duality implemented in the structure volumes (cells and faces are also present in the model. The geometry of a model is constructed explicitly by using Euler operators: connections between elements are created automatically, and semantic information is represented with attributes which can be assigned to any element of the model.

  5. Construction and use of a three-dimensional model as a teaching resource for protein synthesis

    Directory of Open Access Journals (Sweden)

    Alberto Alexandre Lazzaroni

    2017-12-01

    Full Text Available A lot of biology topics are complex and abstract. So, the use of models that can simplify without trivializing knowledge, are important tools for the transposition of academic knowledge in school settings. By understanding the needs of its construction and, due to the lack of a concrete model that exemplifies the protein synthesis, the objective of this work was to elaborate this referred model. For this, the active teaching method was applied as a challenge proposal: the conception of a model conducted by High School students. Once the prototype was built, this strategy was applied to biology graduates, who evaluated and made some criticisms about it. Our results show that the tactic used   was effective. It was verified that the model should be reproduced and that its application facilitated learning of both high school students and undergraduates. We conclude that the availability of this model should contribute to the learning of biochemistry / molecular biology in formal education.

  6. Constructing set-valued fundamental diagrams from jamiton solutions in second order traffic models

    KAUST Repository

    Seibold, Benjamin; Flynn, Morris R.; Kasimov, Aslan R.; Rosales, Rodolfo Rubé n

    2013-01-01

    Fundamental diagrams of vehicular traiic ow are generally multivalued in the congested ow regime. We show that such set-valued fundamental diagrams can be constructed systematically from simple second order macroscopic traiic models, such as the classical Payne-Whitham model or the inhomogeneous Aw-Rascle-Zhang model. These second order models possess nonlinear traveling wave solutions, called jamitons, and the multi-valued parts in the fundamental diagram correspond precisely to jamiton-dominated solutions. This study shows that transitions from function-valued to set-valued parts in a fundamental diagram arise naturally in well-known second order models. As a particular consequence, these models intrinsically reproduce traiic phases. © American Institute of Mathematical Sciences.

  7. Constructing set-valued fundamental diagrams from jamiton solutions in second order traffic models

    KAUST Repository

    Seibold, Benjamin

    2013-09-01

    Fundamental diagrams of vehicular traiic ow are generally multivalued in the congested ow regime. We show that such set-valued fundamental diagrams can be constructed systematically from simple second order macroscopic traiic models, such as the classical Payne-Whitham model or the inhomogeneous Aw-Rascle-Zhang model. These second order models possess nonlinear traveling wave solutions, called jamitons, and the multi-valued parts in the fundamental diagram correspond precisely to jamiton-dominated solutions. This study shows that transitions from function-valued to set-valued parts in a fundamental diagram arise naturally in well-known second order models. As a particular consequence, these models intrinsically reproduce traiic phases. © American Institute of Mathematical Sciences.

  8. Systematic construction of kinetic models from genome-scale metabolic networks.

    Directory of Open Access Journals (Sweden)

    Natalie J Stanford

    Full Text Available The quantitative effects of environmental and genetic perturbations on metabolism can be studied in silico using kinetic models. We present a strategy for large-scale model construction based on a logical layering of data such as reaction fluxes, metabolite concentrations, and kinetic constants. The resulting models contain realistic standard rate laws and plausible parameters, adhere to the laws of thermodynamics, and reproduce a predefined steady state. These features have not been simultaneously achieved by previous workflows. We demonstrate the advantages and limitations of the workflow by translating the yeast consensus metabolic network into a kinetic model. Despite crudely selected data, the model shows realistic control behaviour, a stable dynamic, and realistic response to perturbations in extracellular glucose concentrations. The paper concludes by outlining how new data can continuously be fed into the workflow and how iterative model building can assist in directing experiments.

  9. Systematic Construction of Kinetic Models from Genome-Scale Metabolic Networks

    Science.gov (United States)

    Smallbone, Kieran; Klipp, Edda; Mendes, Pedro; Liebermeister, Wolfram

    2013-01-01

    The quantitative effects of environmental and genetic perturbations on metabolism can be studied in silico using kinetic models. We present a strategy for large-scale model construction based on a logical layering of data such as reaction fluxes, metabolite concentrations, and kinetic constants. The resulting models contain realistic standard rate laws and plausible parameters, adhere to the laws of thermodynamics, and reproduce a predefined steady state. These features have not been simultaneously achieved by previous workflows. We demonstrate the advantages and limitations of the workflow by translating the yeast consensus metabolic network into a kinetic model. Despite crudely selected data, the model shows realistic control behaviour, a stable dynamic, and realistic response to perturbations in extracellular glucose concentrations. The paper concludes by outlining how new data can continuously be fed into the workflow and how iterative model building can assist in directing experiments. PMID:24324546

  10. Usefulness Of Three-Dimensional Printing Models for Patients with Stoma Construction

    Directory of Open Access Journals (Sweden)

    Tetsuro Tominaga

    2016-04-01

    Full Text Available The use of patient-specific organ models in three-dimensional printing systems could be helpful for the education of patients and medical students. The aim of this study was to clarify whether the use of patient-specific stoma models is helpful for patient education. From January 2014 to September 2014, 5 patients who underwent colorectal surgery and for whom a temporary or permanent stoma had been created were involved in this study. Three-dimensional stoma models and three-dimensional face plates were created. The patients’ ages ranged from 59 to 81 years. Four patients underwent stoma construction because of rectal cancer, and 1 underwent stoma construction because of colon stenosis secondary to recurrent cancer. All patients were educated about their stoma and potential stoma-associated problems using three-dimensional stoma models, and all practiced cutting face plates using three-dimensional face plates. The models were also used during medical staff conferences to discuss current issues. All patients understood their problems and finally became self-reliant. The recent availability of three-dimensional printers has enabled the creation of many organ models, and full-scale stoma and face plate models are now available for patient education on cutting an appropriately individualized face plate. Thus, three-dimensional printers could enable fewer skin problems than are currently associated with daily stomal care.

  11. Construction of risk prediction model of type 2 diabetes mellitus based on logistic regression

    Directory of Open Access Journals (Sweden)

    Li Jian

    2017-01-01

    Full Text Available Objective: to construct multi factor prediction model for the individual risk of T2DM, and to explore new ideas for early warning, prevention and personalized health services for T2DM. Methods: using logistic regression techniques to screen the risk factors for T2DM and construct the risk prediction model of T2DM. Results: Male’s risk prediction model logistic regression equation: logit(P=BMI × 0.735+ vegetables × (−0.671 + age × 0.838+ diastolic pressure × 0.296+ physical activity× (−2.287 + sleep ×(−0.009 +smoking ×0.214; Female’s risk prediction model logistic regression equation: logit(P=BMI ×1.979+ vegetables× (−0.292 + age × 1.355+ diastolic pressure× 0.522+ physical activity × (−2.287 + sleep × (−0.010.The area under the ROC curve of male was 0.83, the sensitivity was 0.72, the specificity was 0.86, the area under the ROC curve of female was 0.84, the sensitivity was 0.75, the specificity was 0.90. Conclusion: This study model data is from a compared study of nested case, the risk prediction model has been established by using the more mature logistic regression techniques, and the model is higher predictive sensitivity, specificity and stability.

  12. Large Scale Experiments on Spacecraft Fire Safety

    DEFF Research Database (Denmark)

    Urban, David L.; Ruff, Gary A.; Minster, Olivier

    2012-01-01

    -based microgravity facilities or has been limited to very small fuel samples. Still, the work conducted to date has shown that fire behaviour in low-gravity is very different from that in normal-gravity, with differences observed for flammability limits, ignition delay, flame spread behaviour, flame colour and flame......Full scale fire testing complemented by computer modelling has provided significant knowhow about the risk, prevention and suppression of fire in terrestrial systems (cars, ships, planes, buildings, mines, and tunnels). In comparison, no such testing has been carried out for manned spacecraft due...... to the complexity, cost and risk associ-ated with operating a long duration fire safety experiment of a relevant size in microgravity. Therefore, there is currently a gap in knowledge of fire behaviour in spacecraft. The entire body of low-gravity fire research has either been conducted in short duration ground...

  13. Computer modelling of structures with account of the construction stages and the time dependent material properties

    Directory of Open Access Journals (Sweden)

    Traykov Alexander

    2015-01-01

    Full Text Available Numerical studies are performed on computer models taking into account the stages of construction and time dependent material properties defined in two forms. A 2D model of three storey two spans frame is created. The first form deals with material defined in the usual design practice way - without taking into account the time dependent properties of the concrete. The second form creep and shrinkage of the concrete are taken into account. Displacements and internal forces in specific elements and sections are reported. The influence of the time dependent material properties on the displacement and the internal forces in the main structural elements is tracked down. The results corresponding to the two forms of material definition are compared together as well as with the results obtained by the usual design calculations. Conclusions on the influence of the concrete creep and shrinkage during the construction towards structural behaviour are made.

  14. Individual Travel Behavior Modeling of Public Transport Passenger Based on Graph Construction

    OpenAIRE

    Quan Liang; Jiancheng Weng; Wei Zhou; Selene Baez Santamaria; Jianming Ma; Jian Rong

    2018-01-01

    This paper presents a novel method for mining the individual travel behavior regularity of different public transport passengers through constructing travel behavior graph based model. The individual travel behavior graph is developed to represent spatial positions, time distributions, and travel routes and further forecasts the public transport passenger’s behavior choice. The proposed travel behavior graph is composed of macronodes, arcs, and transfer probability. Each macronode corresponds...

  15. Constructing unified models based on E sub 8 in ten dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Kapetanakis, D. (Technische Univ. Muenchen, Garching (Germany). Fakultaet fuer Physik); Zoupanos, G. (European Organization for Nuclear Research, Geneva (Switzerland))

    1992-10-01

    We examine the virtues and difficulties of the attempts to construct realistic four-dimensional models from a gauge theory based on E{sub 8} and defined in ten dimensions. The four-dimensional theories are obtained using the coset space dimensional reduction scheme. Some of our points and in particular the proposed mechanism for supersymmetry breaking might be useful in other dimensional reduction schemes. (orig.).

  16. The Dif Identification in Constructed Response Items Using Partial Credit Model

    OpenAIRE

    Heri Retnawati

    2017-01-01

    The study was to identify the load, the type and the significance of differential item functioning (DIF) in constructed response item using the partial credit model (PCM). The data in the study were the students’ instruments and the students’ responses toward the PISA-like test items that had been completed by 386 ninth grade students and 460 tenth grade students who had been about 15 years old in the Province of Yogyakarta Special Region in Indonesia. The analysis toward the item characteris...

  17. The construction of next-generation matrices for compartmental epidemic models.

    Science.gov (United States)

    Diekmann, O; Heesterbeek, J A P; Roberts, M G

    2010-06-06

    The basic reproduction number (0) is arguably the most important quantity in infectious disease epidemiology. The next-generation matrix (NGM) is the natural basis for the definition and calculation of (0) where finitely many different categories of individuals are recognized. We clear up confusion that has been around in the literature concerning the construction of this matrix, specifically for the most frequently used so-called compartmental models. We present a detailed easy recipe for the construction of the NGM from basic ingredients derived directly from the specifications of the model. We show that two related matrices exist which we define to be the NGM with large domain and the NGM with small domain. The three matrices together reflect the range of possibilities encountered in the literature for the characterization of (0). We show how they are connected and how their construction follows from the basic model ingredients, and establish that they have the same non-zero eigenvalues, the largest of which is the basic reproduction number (0). Although we present formal recipes based on linear algebra, we encourage the construction of the NGM by way of direct epidemiological reasoning, using the clear interpretation of the elements of the NGM and of the model ingredients. We present a selection of examples as a practical guide to our methods. In the appendix we present an elementary but complete proof that (0) defined as the dominant eigenvalue of the NGM for compartmental systems and the Malthusian parameter r, the real-time exponential growth rate in the early phase of an outbreak, are connected by the properties that (0) > 1 if and only if r > 0, and (0) = 1 if and only if r = 0.

  18. Specification, construction, and exact reduction of state transition system models of biochemical processes.

    Science.gov (United States)

    Bugenhagen, Scott M; Beard, Daniel A

    2012-10-21

    Biochemical reaction systems may be viewed as discrete event processes characterized by a number of states and state transitions. These systems may be modeled as state transition systems with transitions representing individual reaction events. Since they often involve a large number of interactions, it can be difficult to construct such a model for a system, and since the resulting state-level model can involve a huge number of states, model analysis can be difficult or impossible. Here, we describe methods for the high-level specification of a system using hypergraphs, for the automated generation of a state-level model from a high-level model, and for the exact reduction of a state-level model using information from the high-level model. Exact reduction is achieved through the automated application to the high-level model of the symmetry reduction technique and reduction by decomposition by independent subsystems, allowing potentially significant reductions without the need to generate a full model. The application of the method to biochemical reaction systems is illustrated by models describing a hypothetical ion-channel at several levels of complexity. The method allows for the reduction of the otherwise intractable example models to a manageable size.

  19. Oil and gas pipeline construction cost analysis and developing regression models for cost estimation

    Science.gov (United States)

    Thaduri, Ravi Kiran

    In this study, cost data for 180 pipelines and 136 compressor stations have been analyzed. On the basis of the distribution analysis, regression models have been developed. Material, Labor, ROW and miscellaneous costs make up the total cost of a pipeline construction. The pipelines are analyzed based on different pipeline lengths, diameter, location, pipeline volume and year of completion. In a pipeline construction, labor costs dominate the total costs with a share of about 40%. Multiple non-linear regression models are developed to estimate the component costs of pipelines for various cross-sectional areas, lengths and locations. The Compressor stations are analyzed based on the capacity, year of completion and location. Unlike the pipeline costs, material costs dominate the total costs in the construction of compressor station, with an average share of about 50.6%. Land costs have very little influence on the total costs. Similar regression models are developed to estimate the component costs of compressor station for various capacities and locations.

  20. Vibration and Acoustic Testing for Mars Micromission Spacecraft

    Science.gov (United States)

    Kern, Dennis L.; Scharton, Terry D.

    1999-01-01

    spacecraft and the test fixture, alleviates the severe overtest at spacecraft resonances inherent in rigid fixture vibration tests. It has the distinct advantage over response limiting that the method is not dependent on the accuracy of a detailed dynamic model of the spacecraft. Combined loads, vibration, and modal testing were recently performed on the QuikSCAT spacecraft. The combined tests were performed in a single test setup per axis on a vibration shaker, reducing test time by a factor of two or three. Force gages were employed to measure the true c.g. acceleration of the spacecraft for structural loads verification using a sine burst test, to automatically notch random vibration test input accelerations at spacecraft resonances based on predetermined force limits, and to directly measure modal masses in a base drive modal test. In addition to these combined tests on the shaker, the QuikSCAT spacecraft was subjected to a direct field acoustic test by surrounding the spacecraft, still on the vibration shaker, with rock concert type acoustic speakers. Since the spacecraft contractor does not have a reverberant field acoustic test facility, performing a direct field acoustic test -saved the program nearly two weeks schedule time that would have been required for packing / unpacking and shipping of the spacecraft. This paper discusses the rationale behind and advantages of the above test approaches and provides examples of their actual implementation and comparisons to flight data. The applicability of the test approaches to Mars Micromission spacecraft qualification is discussed.