WorldWideScience

Sample records for virtual velocities approach

  1. Virtual velocity loop based on MEMS accelerometers for optical stabilization control system

    Science.gov (United States)

    Ren, Wei; Deng, Chao; Mao, Yao; Ren, Ge

    2017-08-01

    In the optical stabilization control system (OSCS) control system based on a charge-coupled device (CCD), stabilization performance of the line-of-sight is severely limited by the mechanical resonance and the low sampling rate of the CCD. An approach to improve the stabilization performance of the OSCS control system with load restriction based on three loops, including an acceleration loop, a virtual velocity loop, and a position loop, by using MEMS accelerometers and a CCD is proposed. The velocity signal is obtained by accelerators instead of gyro sensors. Its advantages are low power, low cost, small size, and wide measuring range. A detailed analysis is provided to show how to design the virtual velocity loop and correct virtual velocity loop drift. Experimental results show that the proposed multiloop feedback control method with virtual velocity loop in which the disturbance suppression performance is better than that of the dual loop control with only an acceleration loop and a position loop at low frequency.

  2. Streamwise decrease of the 'unsteady' virtual velocity of gravel tracers

    Science.gov (United States)

    Klösch, Mario; Gmeiner, Philipp; Habersack, Helmut

    2017-04-01

    Gravel tracers are usually inserted and transported on top of the riverbed, before they disperse vertically and laterally due to periods of intense bedload, the passage of bed forms, lateral channel migration and storage on bars. Buried grains have a lower probability of entrainment, resulting in a reduction of overall mobility, and, on average, in a deceleration of the particles with distance downstream. As a consequence, the results derived from tracer experiments and their significance for gravel transport may depend on the time scale of the investigation period, complicating the comparison of results from different experiments. We developed a regression method, which establishes a direct link between the transport velocity and the unsteady flow variables to yield an 'unsteady' virtual velocity, while considering the tracer slowdown with distance downstream in the regression. For that purpose, the two parameters of a linear excess shear velocity formula (the critical shear velocity u*c and coefficient a) were defined as functions of the travelled distance since the tracer's insertion. Application to published RFID tracer data from the Mameyes River, Puerto Rico, showed that during the investigation period the critical shear velocity u*c of tracers representing the median bed particle diameter (0.11 m) increased from 0.36 m s-1 to 0.44 m s-1, while the coefficient a decreased from the dimensionless value of 4.22 to 3.53, suggesting a reduction of the unsteady virtual velocity at the highest shear velocity in the investigation period from 0.40 m s-1 to 0.08 m s-1. Consideration of the tracer slowdown improved the root mean square error of the calculated mean displacements of the median bed particle diameter from 8.82 m to 0.34 m. As in previous work these results suggest the need of considering the history of transport when deriving travel distances and travel velocities, depending on the aim of the tracer study. The introduced method now allows estimating the

  3. Automatic Wave Equation Migration Velocity Analysis by Focusing Subsurface Virtual Sources

    KAUST Repository

    Sun, Bingbing

    2017-11-03

    Macro velocity model building is important for subsequent pre-stack depth migration and full waveform inversion. Wave equation migration velocity analysis (WEMVA) utilizes the band-limited waveform to invert for the velocity. Normally, inversion would be implemented by focusing the subsurface offset common image gathers (SOCIGs). We re-examine this concept with a different perspective: In subsurface offset domain, using extended Born modeling, the recorded data can be considered as invariant with respect to the perturbation of the position of the virtual sources and velocity at the same time. A linear system connecting the perturbation of the position of those virtual sources and velocity is derived and solved subsequently by Conjugate Gradient method. In theory, the perturbation of the position of the virtual sources is given by the Rytov approximation. Thus, compared to the Born approximation, it relaxes the dependency on amplitude and makes the proposed method more applicable for real data. We demonstrate the effectiveness of the approach by applying the proposed method on both isotropic and anisotropic VTI synthetic data. A real dataset example verifies the robustness of the proposed method.

  4. A NEW APPROACH TO VIRTUAL EDUCATION

    Directory of Open Access Journals (Sweden)

    Vladimir V. Kureychik

    2014-01-01

    Full Text Available The article discusses several approaches to training, namely the virtual. Concrete examples of virtual learning systems were described, we disclosed their features, advantages and disadvantages. A new suggested approach integrates the features of existing systems, and opens new horizons and opportunities to obtain certain skills and abilities. Introduction of a new approach to the educational process will improve the quality and effectiveness of learning. 

  5. Operational space synchronization of two robot manipulators through a virtual velocity estimate

    Directory of Open Access Journals (Sweden)

    Erik Kyrkjebø

    2008-04-01

    Full Text Available Two robot manipulators are synchronized in a leader-follower scheme where only joint position measurements of the leader are available. A virtual manipulator is designed to provide a velocity estimate of the unknown leader velocity to the control law of the follower. The closed-loop errors are shown to be uniformly globally practically asymptotically stable.

  6. Vector Velocity Imaging Using Cross-Correlation and Virtual Sources

    DEFF Research Database (Denmark)

    Holfort, Iben Kraglund; Kortbek, Jacob; Jensen, Jørgen Arendt

    2006-01-01

    . Using the RASMUS experimental ultrasound scanner, measurements have been carried out in a water tank using a 7~MHz transducer. A 6~mm tube contained the flow and a Danfoss, MAG~3000, magnetic flow meter measured the volume flow. The tube has a parabolic flow profile with a peak velocity of 0.29~m...... estimations of the vector velocities of a larger region by combining the estimations along several scan lines. In combination with a B-mode image, the vector velocities are displayed as an image of the investigated region with a color indicating the magnitude, and arrows showing the direction of the flow....../s. During the experiments fixed beam-to-flow angles at $\\{60^{\\circ}, 75^{\\circ}, 90^{\\circ}\\}$ have been applied. The images are obtained using a pulse repetition frequency of 15~kHz, and the images contain 33~lines with 60~emissions for each line. Corresponding to the three fixed beam-to-flow angles...

  7. Optimizing IT Infrastructure by Virtualization Approach

    Science.gov (United States)

    Budiman, Thomas; Suroso, Jarot S.

    2017-04-01

    The goal of this paper is to get the best potential configuration which can be applied to a physical server without compromising service performance for the clients. Data were compiled by direct observation in the data center observed. Data was then analyzed using the hermeneutics approach to understand the condition by textual data gathered understanding. The results would be the best configuration for a physical server which contains several virtual machines logically separated by its functions. It can be concluded that indeed one physical server machine can be optimized using virtualization so that it may deliver the peak performance of the machine itself and the impact are throughout the organization.

  8. Virtual Reality as Innovative Approach to the Interior Designing

    Science.gov (United States)

    Kaleja, Pavol; Kozlovská, Mária

    2017-06-01

    We can observe significant potential of information and communication technologies (ICT) in interior designing field, by development of software and hardware virtual reality tools. Using ICT tools offer realistic perception of proposal in its initial idea (the study). A group of real-time visualization, supported by hardware tools like Oculus Rift HTC Vive, provides free walkthrough and movement in virtual interior with the possibility of virtual designing. By improving of ICT software tools for designing in virtual reality we can achieve still more realistic virtual environment. The contribution presented proposal of an innovative approach of interior designing in virtual reality, using the latest software and hardware ICT virtual reality technologies

  9. VIRTOPSY - the Swiss virtual autopsy approach.

    Science.gov (United States)

    Thali, Michael J; Jackowski, Christian; Oesterhelweg, Lars; Ross, Steffen G; Dirnhofer, Richard

    2007-03-01

    The aim of the VIRTOPSY project () is utilizing radiological scanning to push low-tech documentation and autopsy procedures in a world of high-tech medicine in order to improve scientific value, to increase significance and quality in the forensic field. The term VIRTOPSY was created from the terms virtual and autopsy: Virtual is derived from the Latin word 'virtus', which means 'useful, efficient and good'. Autopsy is a combination of the old Greek terms 'autos' (=self) and 'opsomei' (=I will see). Thus autopsy means 'to see with ones own eyes'. Because our goal was to eliminate the subjectivity of "autos", we merged the two terms virtual and autopsy - deleting "autos" - to create VIRTOPSY. Today the project VIRTOPSY combining the research topics under one scientific umbrella, is characterized by a trans-disciplinary research approach that combines Forensic Medicine, Pathology, Radiology, Image Processing, Physics, and Biomechanics to an international scientific network. The paper will give an overview of the Virtopsy change process in forensic medicine.

  10. A new virtual instrument for estimating punch velocity in combat sports.

    Science.gov (United States)

    Urbinati, K S; Scheeren, E; Nohama, P

    2013-01-01

    For improving the performance in combat sport, especially percussion, it is necessary achieving high velocity in punches and kicks. The aim of this study was to evaluate the applicability of 3D accelerometry in a Virtual Instrumentation System (VIS) designed for estimating punch velocity in combat sports. It was conducted in two phases: (1) integration of the 3D accelerometer with the communication interface and software for processing and visualization, and (2) applicability of the system. Fifteen karate athletes performed five gyaku zuki type punches (with reverse leg) using the accelerometer on the 3rd metacarpal on the back of the hand. It was performed nonparametric Mann-Whitney U-test to determine differences in the mean linear velocity among three punches performed sequentially (p sport.

  11. Improved virtual cardiac phantom with variable diastolic filling rates and coronary artery velocities

    Science.gov (United States)

    Sturgeon, Gregory M.; Richards, Taylor W.; Samei, E.; Segars, W. P.

    2017-03-01

    To facilitate studies of measurement uncertainty in computed tomography angiography (CTA), we investigated the cardiac motion profile and resulting coronary artery motion utilizing innovative dynamic virtual and physical phantoms. The four-chamber cardiac finite element (FE) model developed in the Living Heart Project (LHP) served as the computational basis for our virtual cardiac phantom. This model provides deformation or strain information at high temporal and spatial resolution, exceeding that of speckle tracking echocardiography or tagged MRI. This model was extended by fitting its motion profile to left ventricular (LV) volume-time curves obtained from patient echocardiography data. By combining the dynamic patient variability from echo with the local strain information from the FE model, a series of virtual 4D cardiac phantoms were developed. Using the computational phantoms, we characterized the coronary motion and its effect on plaque imaging under a range of heart rates subject to variable diastolic function. The coronary artery motion was sampled at 248 spatial locations over 500 consecutive time frames. The coronary artery velocities were calculated as their average velocity during an acquisition window centered at each time frame, which minimized the discretization error. For the initial set of twelve patients, the diastatic coronary artery velocity ranged from 36.5 mm/s to 2.0 mm/s with a mean of 21.4 mm/s assuming an acquisition time of 75 ms. The developed phantoms have great potential in modeling cardiac imaging, providing a known truth and multiple realistic cardiac motion profiles to evaluate different image acquisition or reconstruction methods.

  12. Dependence of kinetic friction on velocity: master equation approach.

    Science.gov (United States)

    Braun, O M; Peyrard, M

    2011-04-01

    We investigate the velocity dependence of kinetic friction with a model that makes minimal assumptions on the actual mechanism of friction so that it can be applied at many scales, provided the system involves multicontact friction. Using a recently developed master equation approach, we investigate the influence of two concurrent processes. First, at a nonzero temperature, thermal fluctuations allow an activated breaking of contacts that are still below the threshold. As a result, the friction force monotonically increases with velocity. Second, the aging of contacts leads to a decrease of the friction force with velocity. Aging effects include two aspects: the delay in contact formation and aging of a contact itself, i.e., the change of its characteristics with the duration of stationary contact. All these processes are considered simultaneously with the master equation approach, giving a complete dependence of the kinetic friction force on the driving velocity and system temperature, provided the interface parameters are known.

  13. Virtual Reality as Innovative Approach to the Interior Designing

    Directory of Open Access Journals (Sweden)

    Kaleja Pavol

    2017-06-01

    Full Text Available We can observe significant potential of information and communication technologies (ICT in interior designing field, by development of software and hardware virtual reality tools. Using ICT tools offer realistic perception of proposal in its initial idea (the study. A group of real-time visualization, supported by hardware tools like Oculus Rift HTC Vive, provides free walkthrough and movement in virtual interior with the possibility of virtual designing. By improving of ICT software tools for designing in virtual reality we can achieve still more realistic virtual environment. The contribution presented proposal of an innovative approach of interior designing in virtual reality, using the latest software and hardware ICT virtual reality technologies

  14. AN INNOVATIVE APPROACH FOR TRAINING IN PROGRAMMING USING VIRTUAL LABORATORIES

    Directory of Open Access Journals (Sweden)

    Galya Shivacheva

    2016-12-01

    Full Text Available The paper describes and analyses the computer programming educational technology in Faculty of Technics and Technologies of Yambol, using traditional methodologies, e-learning and virtual laboratories. It reviews the characteristics of computer programming education, focusing on animation and simulations created by other higher education institutions on algorithm visualizations. The innovative approach has connected with using Moodle Virtual Lab and the Open Judge System for automatic students’ assessment and testing. In addition, the Virtual Laboratory for Training in Programming (VLTP provides a virtual environment with animations, simulations and visualizations of the basic terms, algorithms and data structures in programming sphere.

  15. Virtual imaging anatomy of transnasal approach to the clivus

    Directory of Open Access Journals (Sweden)

    Jun-feng LI

    2012-05-01

    Full Text Available Objective  To observe the virtual anatomy via transnasal approach in a virtual-reality (VR environment, and to establish a virtual anatomical model of clival region and explore the application value of the virtual-reality technology. Methods  Twenty patients (males 11, females 9, aged from 25 to 70 years old with a mean of 43±0.3 years with no pathological changes in the sellar area and clivus underwent CT angiography with Discovery Ultra 16 and 3.0T MRI thin-slice scan. The data were collected and inputted into the Dextroscope in the DICOM format. Virtual observation of anatomy via transnasal approach and three-dimensional reconstruction of clivus were carried out in the VR environment. Results  Virtual reconstruction and measurements of clivus were successfully performed in the 20 patients. The simulation of transnasal approach was also carried out in the VR environment. The lateral side of clival bone removal through transnasal approach was limited by internal carotid artery, the superior limit was sellar floor and the lower clivus could not be revealed completely because of the restriction of the maxilla and hard palate. Conclusions  Virtual reconstruction of the clivus and simulation of transnasal approach can be performed exactly by VR technology, which provides imaginal and anatomical basis in dealing with clivus lesions via transnasal approach.

  16. Surgical training: design of a virtual care pathway approach.

    Science.gov (United States)

    Beyer-Berjot, Laura; Patel, Vishal; Acharya, Amish; Taylor, Dave; Bonrath, Esther; Grantcharov, Teodor; Darzi, Ara; Aggarwal, Rajesh

    2014-09-01

    Both intra- and perioperative care are essential for patients' safety. Training for intraoperative technical skills on simulators and for perioperative care in virtual patients have independently demonstrated educational value, but no training combining these 2 approaches has been designed yet. The aim of this study was to design a pathway approach for training in general surgery. A common disease requiring essential skills was chosen, namely, acute appendicitis. Preoperative care training was created using virtual patients presenting with acute right iliac fossa (RIF) pain. A competency-based curriculum for laparoscopic appendectomy (LAPP) was designed on a virtual reality simulator: Novices (100 LAPP) were enrolled to perform 2 virtual LAPP for assessment of validity evidence; novices performed 8 further LAPP for analysis of a learning curve. Finally, postoperative virtual patients were reviewed after LAPP. Four preoperative patient scenarios were designed with different presentations of RIF; not all required operative management. Comments were provided through case progression to allow autonomous practice. Ten novices and 10 experienced surgeons were enrolled for intraoperative training. Time taken (median values) of novices versus experienced surgeons (285 vs 259 seconds; P = .026) and performance score (67% vs 99%; P virtual patients were created with an uneventful or complicated outcome. A virtual care pathway approach has been designed for acute appendicitis, enabling trainees to follow simulated patients from admission to discharge. Copyright © 2014 Mosby, Inc. All rights reserved.

  17. Ice flood velocity calculating approach based on single view metrology

    Science.gov (United States)

    Wu, X.; Xu, L.

    2017-02-01

    Yellow River is the river in which the ice flood occurs most frequently in China, hence, the Ice flood forecasting has great significance for the river flood prevention work. In various ice flood forecast models, the flow velocity is one of the most important parameters. In spite of the great significance of the flow velocity, its acquisition heavily relies on manual observation or deriving from empirical formula. In recent years, with the high development of video surveillance technology and wireless transmission network, the Yellow River Conservancy Commission set up the ice situation monitoring system, in which live videos can be transmitted to the monitoring center through 3G mobile networks. In this paper, an approach to get the ice velocity based on single view metrology and motion tracking technique using monitoring videos as input data is proposed. First of all, River way can be approximated as a plane. On this condition, we analyze the geometry relevance between the object side and the image side. Besides, we present the principle to measure length in object side from image. Secondly, we use LK optical flow which support pyramid data to track the ice in motion. Combining the result of camera calibration and single view metrology, we propose a flow to calculate the real velocity of ice flood. At last we realize a prototype system by programming and use it to test the reliability and rationality of the whole solution.

  18. Exploring Approaches to Teaching in Three-Dimensional Virtual Worlds

    Science.gov (United States)

    Englund, Claire

    2017-01-01

    Purpose: The purpose of this paper is to explore how teachers' approaches to teaching and conceptions of teaching and learning with educational technology influence the implementation of three-dimensional virtual worlds (3DVWs) in health care education. Design/methodology/approach: Data were collected through thematic interviews with eight…

  19. Physics-based preoperative approach planning using hybrid virtual bodies.

    Science.gov (United States)

    Nakao, Megumi; Kuroda, Tomohiro; Komori, Masaru; Oyama, Hiroshi; Komeda, Masashi

    2004-01-01

    This paper proposes a hybrid model mixing geometry and volume data to improve representation of virtual bodies. This model applies object-oriented data models and rendering techniques to virtual organs, and enables both interactive VR simulation and detailed volume visualization of tissue of interest (e.g. coronary). Also, a physics-based framework interactively simulates estimated surgical fields which are used in preoperative discussion. Based on the proposed methods, a VR-based strategic planning system is developed. The system does not need high cost manual segmentation of patient dataset and efficiently supports planning of surgical approaches in cardiovascular surgery.

  20. The Limit Deposit Velocity model : A new approach

    NARCIS (Netherlands)

    Miedema, S.A.; Ramsdell, R.C.

    2015-01-01

    In slurry transport of settling slurries in Newtonian fluids, it is often stated that one should apply a line speed above a critical velocity, because blow this critical velocity there is the danger of plugging the line. There are many definitions and names for this critical velocity. It is referred

  1. Evaluation of a 'virtual' approach to commissioning health research

    OpenAIRE

    McCourt, Christine A; Morgan, Philip A; Youll, Penny

    2006-01-01

    Abstract Background The objective of this study was to evaluate the implementation of a 'virtual' (computer-mediated) approach to health research commissioning. This had been introduced experimentally in a DOH programme – the 'Health of Londoners Programme' – in order to assess whether is could enhance the accessibility, transparency and effectiveness of commissioning health research. The study described here was commissioned to evaluate this novel approach, addressing these key questions. Me...

  2. Evaluation of a 'virtual' approach to commissioning health research.

    Science.gov (United States)

    McCourt, Christine A; Morgan, Philip A; Youll, Penny

    2006-10-18

    The objective of this study was to evaluate the implementation of a 'virtual' (computer-mediated) approach to health research commissioning. This had been introduced experimentally in a DOH programme--the 'Health of Londoners Programme'--in order to assess whether is could enhance the accessibility, transparency and effectiveness of commissioning health research. The study described here was commissioned to evaluate this novel approach, addressing these key questions. A naturalistic-experimental approach was combined with principles of action research. The different commissioning groups within the programme were randomly allocated to either the traditional face-to-face mode or the novel 'virtual' mode. Mainly qualitative data were gathered including observation of all (virtual and face-to-face) commissioning meetings; semi-structured interviews with a purposive sample of participants (n = 32/66); structured questionnaires and interviews with lead researchers of early commissioned projects. All members of the commissioning groups were invited to participate in collaborative enquiry groups which participated actively in the analysis process. The virtual process functioned as intended, reaching timely and relatively transparent decisions that participants had confidence in. Despite the potential for greater access using a virtual approach, few differences were found in practice. Key advantages included physical access, a more flexible and extended time period for discussion, reflection and information gathering and a more transparent decision-making process. Key challenges were the reduction of social cues available in a computer-mediated medium that require novel ways of ensuring appropriate dialogue, feedback and interaction. However, in both modes, the process was influenced by a range of factors and was not technology driven. There is potential for using computer-mediated communication within the research commissioning process. This may enhance access

  3. Evaluation of a 'virtual' approach to commissioning health research

    Directory of Open Access Journals (Sweden)

    Morgan Philip A

    2006-10-01

    Full Text Available Abstract Background The objective of this study was to evaluate the implementation of a 'virtual' (computer-mediated approach to health research commissioning. This had been introduced experimentally in a DOH programme – the 'Health of Londoners Programme' – in order to assess whether is could enhance the accessibility, transparency and effectiveness of commissioning health research. The study described here was commissioned to evaluate this novel approach, addressing these key questions. Methods A naturalistic-experimental approach was combined with principles of action research. The different commissioning groups within the programme were randomly allocated to either the traditional face-to-face mode or the novel 'virtual' mode. Mainly qualitative data were gathered including observation of all (virtual and face-to-face commissioning meetings; semi-structured interviews with a purposive sample of participants (n = 32/66; structured questionnaires and interviews with lead researchers of early commissioned projects. All members of the commissioning groups were invited to participate in collaborative enquiry groups which participated actively in the analysis process. Results The virtual process functioned as intended, reaching timely and relatively transparent decisions that participants had confidence in. Despite the potential for greater access using a virtual approach, few differences were found in practice. Key advantages included physical access, a more flexible and extended time period for discussion, reflection and information gathering and a more transparent decision-making process. Key challenges were the reduction of social cues available in a computer-mediated medium that require novel ways of ensuring appropriate dialogue, feedback and interaction. However, in both modes, the process was influenced by a range of factors and was not technology driven. Conclusion There is potential for using computer-mediated communication within

  4. IT virtualization best practices a lean, green virtualized data center approach

    CERN Document Server

    Iqbal, Mickey; Molloy, Chris; Rymarczyk, Jim

    2011-01-01

    Written by experts in the field, this indispensable guide provides a services-patterns approach to transforming IT infrastructures to a virtualized state to derive compelling business value for organizations. Thorough and informative, this account will demonstrate how businesses can become more productive in managing overall costs, more agile in provisioning new business services and improving time to market, more proactive in catering to rapidly changing business models and client demands, and more charged as an engine for fueling business growth.

  5. Novel approach for prediction of ultrasonic velocity in quaternary ...

    Indian Academy of Sciences (India)

    2 lists the values of the experimental ultrasonic velocity taken from literature [5], theoretically computed values of ultrasonic velocity using Flory relation, Auerbach and Altenberg relations along with their average percentage deviations at 298.15. K, using eqs (1), (2) and (5). Figures 1a–c provide a graphical representation of ...

  6. Approaches in integrative bioinformatics towards the virtual cell

    CERN Document Server

    Chen, Ming

    2014-01-01

    Approaches in Integrative Bioinformatics provides a basic introduction to biological information systems, as well as guidance for the computational analysis of systems biology. This book also covers a range of issues and methods that reveal the multitude of omics data integration types and the relevance that integrative bioinformatics has today. Topics include biological data integration and manipulation, modeling and simulation of metabolic networks, transcriptomics and phenomics, and virtual cell approaches, as well as a number of applications of network biology. It helps to illustrat

  7. Novel approach for prediction of ultrasonic velocity in quaternary ...

    Indian Academy of Sciences (India)

    A modified Flory theory along with the Auerbach and Altenberg relations has been employed for the computation of ultrasonic velocity of three quaternary liquid mixtures and a comparative study of all the three relations has then been carried out.

  8. An approach towards problem-based learning in virtual space.

    Science.gov (United States)

    Freudenberg, Lutz S; Bockisch, Andreas; Beyer, Thomas

    2010-01-01

    Problem-based learning (PBL) is an established and efficient approach to sustainable teaching. Here, we describe translation of PBL into the virtual classroom thereby offering novel teaching aspects in the field of Nuclear Medicine. Our teaching approach is implemented on a "moodle" platform and consists of 2 modules: complementary seminar teaching materials and a virtual PBL-classroom, which can be attended via Skype.Over the course of 4 semesters 539 students have accessed our teaching platform. 21 students have participated in the PBL seminar (module 2). After resolving some minor technical difficulties our virtual seminars have evolved into a forum of intense studies, whereby the participating students have learned to become more independent along the workup of the teaching cases. This was reflected in the results of the intra-group presentations and discussions.Quantitative and qualitative evaluation of our moodle-based PBL platform indicates an increasing level of acceptance and enthusiasm by the students. This has initiated discussions about opening our PBL concept to a wider audience within the university and beyond the Nuclear Medicine specialty.

  9. Machinima interventions: innovative approaches to immersive virtual world curriculum integration

    Directory of Open Access Journals (Sweden)

    Andrew John Middleton

    2008-12-01

    Full Text Available The educational value of Immersive Virtual Worlds (IVWs seems to be in their social immersive qualities and as an accessible simulation technology. In contrast to these synchronous applications this paper discusses the use of educational machinima developed in IVW virtual film sets. It also introduces the concept of media intervention, proposing that digital media works best when simply developed for deployment within a blended curriculum to inform learning activity, and where the media are specifically designed to set challenges, seed ideas, or illustrate problems. Machinima, digital films created in IVWs, or digital games offer a rich mechanism for delivering such interventions. Scenes are storyboarded, constructed, shot and edited using techniques similar to professional film production, drawing upon a cast of virtual world avatars controlled through a human–computer interface, rather than showing real-life actors. The approach enables academics or students to make films using screen capture software and desktop editing tools. In student-generated production models the learning value may be found in the production process itself. This paper discusses six case studies and several themes from research on ideas for educational machinima including: access to production; creativity in teaching and learning; media intervention methodology; production models; reusability; visualisation and simulation.

  10. A Cooperative Approach to Virtual Machine Based Fault Injection

    Energy Technology Data Exchange (ETDEWEB)

    Naughton III, Thomas J [ORNL; Engelmann, Christian [ORNL; Vallee, Geoffroy R [ORNL; Aderholdt, William Ferrol [ORNL; Scott, Stephen L [Tennessee Technological University (TTU)

    2017-01-01

    Resilience investigations often employ fault injection (FI) tools to study the effects of simulated errors on a target system. It is important to keep the target system under test (SUT) isolated from the controlling environment in order to maintain control of the experiement. Virtual machines (VMs) have been used to aid these investigations due to the strong isolation properties of system-level virtualization. A key challenge in fault injection tools is to gain proper insight and context about the SUT. In VM-based FI tools, this challenge of target con- text is increased due to the separation between host and guest (VM). We discuss an approach to VM-based FI that leverages virtual machine introspection (VMI) methods to gain insight into the target s context running within the VM. The key to this environment is the ability to provide basic information to the FI system that can be used to create a map of the target environment. We describe a proof- of-concept implementation and a demonstration of its use to introduce simulated soft errors into an iterative solver benchmark running in user-space of a guest VM.

  11. Application of Migration Velocity Using Fourier Transform Approach ...

    African Journals Online (AJOL)

    Application of velocity by Fourier transform to process 3-D unmigrated seismic sections has been carried out in Fabi Field, Niger Delta – Nigeria. Usually, all seismic events (sections) are characterized by spikes or noise (random or coherent), multiples and shear waves so that when a seismic bed is dipping, the apparent ...

  12. The effect of increasing strength and approach velocity on triple jump performance.

    Science.gov (United States)

    Allen, Sam J; Yeadon, M R Fred; King, Mark A

    2016-12-08

    The triple jump is an athletic event comprising three phases in which the optimal phase ratio (the proportion of each phase to the total distance jumped) is unknown. This study used a planar whole body torque-driven computer simulation model of the ground contact parts of all three phases of the triple jump to investigate the effect of strength and approach velocity on optimal performance. The strength and approach velocity of the simulation model were each increased by up to 30% in 10% increments from baseline data collected from a national standard triple jumper. Increasing strength always resulted in an increased overall jump distance. Increasing approach velocity also typically resulted in an increased overall jump distance but there was a point past which increasing approach velocity without increasing strength did not lead to an increase in overall jump distance. Increasing both strength and approach velocity by 10%, 20%, and 30% led to roughly equivalent increases in overall jump distances. Distances ranged from 14.05m with baseline strength and approach velocity, up to 18.49m with 30% increases in both. Optimal phase ratios were either hop-dominated or balanced, and typically became more balanced when the strength of the model was increased by a greater percentage than its approach velocity. The range of triple jump distances that resulted from the optimisation process suggests that strength and approach velocity are of great importance for triple jump performance. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. An Iterative Adaptive Approach for Blood Velocity Estimation Using Ultrasound

    DEFF Research Database (Denmark)

    Gudmundson, Erik; Jakobsson, Andreas; Jensen, Jørgen Arendt

    2010-01-01

    This paper proposes a novel iterative data-adaptive spectral estimation technique for blood velocity estimation using medical ultrasound scanners. The technique makes no assumption on the sampling pattern of the slow-time or the fast-time samples, allowing for duplex mode transmissions where B......-mode images are interleaved with the Doppler emissions. Furthermore, the technique is shown, using both simplified and more realistic Field II simulations, to outperform current state-of-the-art techniques, allowing for accurate estimation of the blood velocity spectrum using only 30% of the transmissions......, thereby allowing for the examination of two separate vessel regions while retaining an adequate updating rate of the B-mode images. In addition, the proposed method also allows for more flexible transmission patterns, as well as exhibits fewer spectral artifacts as compared to earlier techniques....

  14. Blood velocity estimation using ultrasound and spectral iterative adaptive approaches

    DEFF Research Database (Denmark)

    Gudmundson, Erik; Jakobsson, Andreas; Jensen, Jørgen Arendt

    2011-01-01

    This paper proposes two novel iterative data-adaptive spectral estimation techniques for blood velocity estimation using medical ultrasound scanners. The techniques make no assumption on the sampling pattern of the emissions or the depth samples, allowing for duplex mode transmissions where B......-mode images are interleaved with the Doppler emissions. Furthermore, the techniques are shown, using both simplified and more realistic Field II simulations as well as in vivo data, to outperform current state-of-the-art techniques, allowing for accurate estimation of the blood velocity spectrum using only 30......% of the transmissions, thereby allowing for the examination of two separate vessel regions while retaining an adequate updating rate of the B-mode images. In addition, the proposed methods also allow for more flexible transmission patterns, as well as exhibit fewer spectral artifacts as compared to earlier techniques....

  15. Towards a Methodology for Managing Competencies in Virtual Teams - A Systemic Approach

    Science.gov (United States)

    Schumacher, Marinita; Stal-Le Cardinal, Julie; Bocquet, Jean-Claude

    Virtual instruments and tools are future trends in Engineering which are a response to the growing complexity of engineering tasks, the facility of communication and strong collaborations on the international market. Outsourcing, off-shoring, and the globalization of organisations’ activities have resulted in the formation of virtual product development teams. Individuals who are working in virtual teams must be equipped with diversified competencies that provide a basis for virtual team building. Thanks to the systemic approach of the functional analysis our paper responds to the need of a methodology of competence management to build virtual teams that are active in virtual design projects in the area of New Product Development (NPD).

  16. Virtual Reality as Innovative Approach to the Interior Designing

    National Research Council Canada - National Science Library

    Pavol Kaleja; Mária Kozlovská

    2017-01-01

    ...). A group of real-time visualization, supported by hardware tools like Oculus Rift HTC Vive, provides free walkthrough and movement in virtual interior with the possibility of virtual designing...

  17. Cognitive Agents in Virtual Worlds : a Middleware Design Approach

    NARCIS (Netherlands)

    van Oijen, Joost|info:eu-repo/dai/nl/326053948

    2014-01-01

    In the past decade, significant advances have been made in the technologies for creating virtual worlds. These advances are accompanied with the need for intelligent, human-like characters to populate these virtual worlds. Such characters are also known as intelligent virtual agents (IVAs). IVAs are

  18. SHOCK-WAVE VELOCITY AND SHOCK PRESSURE FOR LOW-DENSITY POWDERS - A NOVEL-APPROACH

    NARCIS (Netherlands)

    DIJKEN, DK; DEHOSSON, JTM

    1994-01-01

    A novel approach is presented to predict the shock wave velocity as well as the shock wave pressure in powder materials. It is shown that the influence of the specific volume behind the shock wave on shock wave velocity and shock pressure decreases with decreasing initial powder density. The new

  19. Shock wave velocity and shock pressure for low density powders : A novel approach

    NARCIS (Netherlands)

    Dijken, D.K.; Hosson, J.Th.M. De

    1994-01-01

    A novel approach is presented to predict the shock wave velocity as well as the shock wave pressure in powder materials. It is shown that the influence of the specific volume behind the shock wave on shock wave velocity and shock pressure decreases with decreasing initial powder density. The new

  20. Virtual networks pluralistic approach for the next generation of Internet

    CERN Document Server

    Duarte, Otto Carlos M B

    2013-01-01

    The first chapter of this title concerns virtualization techniques that allow sharing computational resources basically, slicing a real computational environment into virtual computational environments that are isolated from one another.The Xen and OpenFlow virtualization platforms are then presented in Chapter 2 and a performance analysis of both is provided. This chapter also defines the primitives that the network virtualization infrastructure must provide for allowing the piloting plane to manage virtual network elements.Following this, interfaces for system management of the two platform

  1. Virtual autopsy: preliminary experience in high-velocity gunshot wound victims.

    Science.gov (United States)

    Levy, Angela D; Abbott, Robert M; Mallak, Craig T; Getz, John M; Harcke, H Theodore; Champion, Howard R; Pearse, Lisa A

    2006-08-01

    To retrospectively assess virtual autopsy performed with multidetector computed tomography (CT) for the forensic evaluation of gunshot wound victims. The institutional review board approved this HIPAA-compliant study and did not require informed consent of the next of kin. Thirteen consecutive male gunshot wound victims (mean age, 27 years) were scanned with 16-section multidetector CT prior to routine autopsy. Retrospectively, the total-body nonenhanced scans were interpreted at a three-dimensional workstation by radiologists blinded to autopsy findings. Images were evaluated for lethal wound, number and location of wound tracks, injured structures, and metal fragment location. After image review, autopsy reports and photographs were compared with the images and interpretations to validate the multidetector CT determinations. Multidetector CT aided in correct identification of all lethal wounds, and metallic fragment location was always precise. In four cases, multidetector CT aided in accurate assessment of organ injuries and lethal wounds but led to underestimation of the number of wounds if comingling paths occurred. In two cases of a chest wound, multidetector CT aided in accurate assessment of the chest as having the lethal wound but failed to help identify specific sites of hemorrhage. In two cases of craniofacial injury, the path of the wound was not clear. Autopsy revealed a total of 78 wound tracks (mean, 6; range, 1-24). Ten (13%) wound tracks were not identified at multidetector CT (six upper extremity wounds and four thigh wounds). In two cases, findings missed at autopsy (fracture of the cervical spine, bullet fragments in the posterior area of the neck) were identified at multidetector CT. Multidetector CT can aid prediction of lethal wounds and location of metallic fragments.

  2. DEVELOPING DYNAMIC VIRTUAL ENVIRONMENTS USING HIERARCHICAL, TREE-STRUCTURED APPROACH

    OpenAIRE

    Wan Mohd Rizhan Wan Idris; Elissa Nadia Madi; Md Yazid Mohd Saman

    2015-01-01

    Virtual reality (VR) has been utilized in various applications such as in architecture, medicine, advertisement, business, entertainment, and education. In the world of simulation, VR software allows users to visualize, manipulate and interact with the computers and complex data. However, developing VR environments is costly and expensive. Highly-technical persons are needed to create the virtual objects from scratch. Once a virtual system is created, managing and modifying it creates further...

  3. Virtual Reality as Innovative Approach to the Interior Designing

    OpenAIRE

    Kaleja Pavol; Kozlovská Mária

    2017-01-01

    We can observe significant potential of information and communication technologies (ICT) in interior designing field, by development of software and hardware virtual reality tools. Using ICT tools offer realistic perception of proposal in its initial idea (the study). A group of real-time visualization, supported by hardware tools like Oculus Rift HTC Vive, provides free walkthrough and movement in virtual interior with the possibility of virtual designing. By improving of ICT software tools ...

  4. Archeovirtual 2011: An evaluation approach to virtual museums

    NARCIS (Netherlands)

    Pescarin, S.; Pagano, A.; Wallergård, M.; Hupperetz, W.; Ray, C.; Guidi, G.; Addison, A.C.

    2012-01-01

    November 2011 saw the opening of the exhibition "Archeovirtual" organized by CNR ITABC - Virtual Heritage Lab - and V-MusT Network of Excellence, in Paestum, Italy, under the general direction of BMTA1. The event, that was part of a wider European project focus on virtual museums, turned to be a

  5. Quality Improvement in Virtual Higher Education: A Grounded Theory Approach

    Science.gov (United States)

    Mahdiuon, Rouhollah; Masoumi, Davoud; Farasatkhah, Maghsoud

    2017-01-01

    The article aims to explore the attributes of quality and quality improvement including the process and specific actions associated with these attributes--that contribute enhancing quality in Iranian Virtual Higher Education (VHE) institutions. A total of 16 interviews were conducted with experts and key actors in Iranian virtual higher education.…

  6. Development of a Virtual Approach-Avoidance Task to Assess Alcohol Cravings.

    Science.gov (United States)

    Kim, Deok-Yong; Lee, Jang-Han

    2015-12-01

    The aim of the present study was to develop a new approach-avoidance task in a virtual environment that could be used to assess the response to virtual alcohol-related situations by heavy social drinkers (HSDs) and light social drinkers (LSDs). Thirty-six male undergraduates (18 HSDs, 18 LSDs) responded to signals when they pulled or pushed a joystick after watching scenes of alcohol- or nonalcohol-related situations in a virtual environment. The HSD group spent more time on moving away from alcohol-related situations than nonalcohol-related situations. We found that the HSD group had difficulty in avoiding alcohol-related situations in the virtual environment. The Virtual Approach-Avoidance Task might more accurately measure the levels of social drinkers' craving to drink as it provides realistic situations and allows individuals to be immersed in virtual environments.

  7. Asymmetric Velocity Distributions from Halo Density Profiles in the Eddington Approach

    Directory of Open Access Journals (Sweden)

    J. D. Vergados

    2015-01-01

    Full Text Available We show how to obtain the energy distribution f(E in our vicinity starting from WIMP density profiles in a self-consistent way by employing the Eddington approach and adding reasonable angular momentum dependent terms in the expression of the energy. We then show how we can obtain the velocity dispersions and the asymmetry parameter β in terms of the parameters describing the angular momentum dependence. From this expression, for f(E, we proceed to construct an axially symmetric WIMP a velocity distribution, which, for a gravitationally bound system, automatically has a velocity upper bound and is characterized by the same asymmetriy β. This approach is tested and clarified by constructing analytic expressions in a simple model, with adequate structure. We then show how such velocity distributions can be used in determining the event rates, including modulation, in both the standard and the directional WIMP searches.

  8. Diagnostics of Cold-Sprayed Particle Velocities Approaching Critical Deposition Conditions

    Science.gov (United States)

    Mauer, G.; Singh, R.; Rauwald, K.-H.; Schrüfer, S.; Wilson, S.; Vaßen, R.

    2017-10-01

    In cold spraying, the impact particle velocity plays a key role for successful deposition. It is well known that only those particles can achieve successful bonding which have an impact velocity exceeding a particular threshold. This critical velocity depends on the thermomechanical properties of the impacting particles at impacting temperature. The latter depends on the gas temperature in the torch but also on stand-off distance and gas pressure. In the past, some semiempirical approaches have been proposed to estimate particle impact and critical velocities. Besides that, there are a limited number of available studies on particle velocity measurements in cold spraying. In the present work, particle velocity measurements were performed using a cold spray meter, where a laser beam is used to illuminate the particles ensuring sufficiently detectable radiant signal intensities. Measurements were carried out for INCONEL® alloy 718-type powders with different particle sizes. These experimental investigations comprised mainly subcritical spray parameters for this material to have a closer look at the conditions of initial deposition. The critical velocities were identified by evaluating the deposition efficiencies and correlating them to the measured particle velocity distributions. In addition, the experimental results were compared with some values estimated by model calculations.

  9. The Virtual University: A Smart Card Approach to Education?

    Science.gov (United States)

    Recker, Mimi

    1998-01-01

    Argues that the emergence of digital marketplaces for learning has broad implications for the standardization and commercialization of education. Defines the concept of the virtual university and discusses how traditional institutions could be reconceived by adopting an alternative model. (PEN)

  10. New Developments in Vector Velocity Imaging using the Transverse Oscillation Approach

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Pihl, Michael Johannes; Olesen, Jacob Bjerring

    2013-01-01

    Vector velocity imaging using the Transverse Oscillation (TO) approach has recently been FDA approved for linear array transducers on a commercial platform. It can now be used clinically for studying the complex flow at e.g. bifurcations, valves, and the heart in real time. Several clinical...

  11. Approaching a reliable process simulation for the virtual product development

    NARCIS (Netherlands)

    Kose, K.; Rietman, Bert; Tikhomirov, D.; Bessert, N.

    2005-01-01

    In this paper an outline for a strategy to include manufacturing effects in subsequent simulations for the virtual product development from an industrial point of view is given. Especially the conditions for a successful mapping of geometry and results between different applications are discussed.

  12. Formation control of unicycle mobile robots: a virtual structure approach

    NARCIS (Netherlands)

    Broek, T.H.A. van den; Wouw, N. van de; Nijmeijer, H.

    2009-01-01

    In this paper, the formation control problem for unicycle mobile robots is studied. A virtual structure control strategy with mutual coupling between the robots is proposed. The rationale behind the introduction of the coupling terms is the fact that these introduce additional robustness with

  13. Virtual Environments and Autism: A Developmental Psychopathological Approach

    Science.gov (United States)

    Rajendran, G.

    2013-01-01

    Individuals with autism spectrum disorders supposedly have an affinity with information and communication technology (ICT), making it an ideally suited media for this population. Virtual environments (VEs)--both two-dimensional and immersive--represent a particular kind of ICT that might be of special benefit. Specifically, this paper discusses…

  14. A finite difference approach to despiking in-stationary velocity data - tested on a triple-lidar

    DEFF Research Database (Denmark)

    Meyer Forsting, Alexander Raul; Troldborg, Niels

    2016-01-01

    A novel despiking method is presented for in-stationary wind lidar velocity measurements. A finite difference approach yields the upper and lower bounds for a valid velocity reading. The sole input to the algorithm is the velocity series and optionally a far- field reference to the temporal...

  15. A virtual maintenance-based approach for satellite assembling and troubleshooting assessment

    Science.gov (United States)

    Geng, Jie; Li, Ying; Wang, Ranran; Wang, Zili; Lv, Chuan; Zhou, Dong

    2017-09-01

    In this study, a Virtual Maintenance (VM)-based approach for satellite troubleshooting assessment is proposed. By focusing on various elements in satellite assemble troubleshooting, such as accessibility, ergonomics, wiring, and extent of damage, a systematic, quantitative, and objective assessment model is established to decrease subjectivity in satellite assembling and troubleshooting assessment. Afterwards, based on the established assessment model and satellite virtual prototype, an application process of this model suitable for a virtual environment is presented. Finally, according to the application process, all the elements in satellite troubleshooting are analyzed and assessed. The corresponding improvements, which realize the transformation from a conventional way to a virtual simulation and assessment, are suggested, and the flaws in assembling and troubleshooting are revealed. Assembling or troubleshooting schemes can be improved in the early stage of satellite design with the help of a virtual prototype. Repetition in the practical operation is beneficial to companies as risk and cost are effectively reduced.

  16. Virtual Engineering Approach to Developing Selective Harvest Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Kevin L. Kenney; Christopher T. Wright

    2005-07-01

    Agricultural crop residues (e.g., straw and stover) are a current focus for bioenergy feedstocks, with new technologies being developed to improve the economics of bioenergy production. Among the emerging technologies focused on feedstock engineering is the selective harvest concept. Due to the complexity of the biomass separations required for addressing the challenges and requirements of selective harvest, high fidelity models and advanced experimental methods that allow observation and measurement of the physical system are needed. These models and methods were developed and include computational fluid dynamics (CFD) modeling to simulate the cleaning shoe of a grain combine and a particle image velocimetry (PIV) technique to quantitatively and qualitatively characterize the cleaning shoe performance. While these techniques alone can be sufficient engineering and analysis tools for developing selective harvest technologies, this paper presents a new methodology, Virtual Engineering (VE), that integrates the CFD and PIV data into a virtual environment, where the data is coupled with the geometric model of a grain combine to provide a virtual representation of the cleaning shoe performance. Using VE visualization capabilities, the CFD and PIV data can be viewed in the context of the physical system for an interactive evaluation of characteristics and performance. This paper also discusses the concepts of additional VE tools that are being developed to provide necessary visualization, simulation and integration functionality.

  17. A Methodological Approach to User Evaluation and Assessment of a Virtual Environment Hangout

    Directory of Open Access Journals (Sweden)

    Marco Pasin

    2015-08-01

    Full Text Available Innovation in virtual reality and motion sensing devices is pushing the development of virtual communication platforms towards completely immersive scenarios, which require full user interaction and create complex sensory experiences. This evolution influences user experiences and creates new paradigms for interaction, leading to an increased importance of user evaluation and assessment on new systems interfaces and usability, to validate platform design and development from the users’ point of view. The REVERIE research project aims to develop a virtual environment service for realistic inter-personal interaction. This paper describes the design challenges faced during the development process of user interfaces and the adopted methodological approach to user evaluation and assessment.

  18. Towards an Approach for an Accessible and Inclusive Virtual Education Using ESVI-AL Project Results

    Science.gov (United States)

    Amado-Salvatierra, Hector R.; Hilera, Jose R.

    2015-01-01

    Purpose: This paper aims to present an approach to achieve accessible and inclusive Virtual Education for all, but especially intended for students with disabilities. This work proposes main steps to take into consideration for stakeholders involved in the educational process related to an inclusive e-Learning. Design/methodology/approach: The…

  19. Dry deposition models for radionuclides dispersed in air: a new approach for deposition velocity evaluation schema

    Science.gov (United States)

    Giardina, M.; Buffa, P.; Cervone, A.; De Rosa, F.; Lombardo, C.; Casamirra, M.

    2017-11-01

    In the framework of a National Research Program funded by the Italian Minister of Economic Development, the Department of Energy, Information Engineering and Mathematical Models (DEIM) of Palermo University and ENEA Research Centre of Bologna, Italy are performing several research activities to study physical models and mathematical approaches aimed at investigating dry deposition mechanisms of radioactive pollutants. On the basis of such studies, a new approach to evaluate the dry deposition velocity for particles is proposed. Comparisons with some literature experimental data show that the proposed dry deposition scheme can capture the main phenomena involved in the dry deposition process successfully.

  20. Hit expansion approaches using multiple similarity methods and virtualized query structures.

    Science.gov (United States)

    Bergner, Andreas; Parel, Serge P

    2013-05-24

    Ligand-based virtual screening and computational hit expansion methods undoubtedly facilitate the finding of novel active chemical entities, utilizing already existing knowledge of active compounds. It has been demonstrated that the parallel execution of complementary similarity search methods enhances the performance of such virtual screening campaigns. In this article, we examine the use of virtualized template (query, seed) structures as an extension to common search methods, such as fingerprint and pharmacophore graph-based similarity searches. We demonstrate that template virtualization by bioisosteric enumeration and other rule-based methods, in combination with standard similarity search techniques, represents a powerful approach for hit expansion following high-throughput screening campaigns. The reliability of the methods is demonstrated by four different test data sets representing different target classes and two hit finding case studies on the epigenetic targets G9a and LSD1.

  1. Comparison of pressure reconstruction approaches based on measured and simulated velocity fields

    Directory of Open Access Journals (Sweden)

    Manthey Samuel

    2017-09-01

    Full Text Available The pressure drop over a pathological vessel section can be used as an important diagnostic indicator. However, it cannot be measured non-invasively. Multiple approaches for pressure reconstruction based on velocity information are available. Regarding in-vivo data introducing uncertainty these approaches may not be robust and therefore validation is required. Within this study, three independent methods to calculate pressure losses from velocity fields were implemented and compared: A three dimensional and a one dimensional method based on the Pressure Poisson Equation (PPE as well as an approach based on the work-energy equation for incompressible fluids (WERP. In order to evaluate the different approaches, phantoms from pure Computational Fluid Dynamics (CFD simulations and in-vivo PC-MRI measurements were used. The comparison of all three methods reveals a good agreement with respect to the CFD pressure solutions for simple geometries. However, for more complex geometries all approaches lose accuracy. Hence, this study demonstrates the need for a careful selection of an appropriate pressure reconstruction algorithm.

  2. Building Virtual Collaborative Research Community Using Knowledge Management Approach

    Directory of Open Access Journals (Sweden)

    Ju-Ling Shih

    2010-09-01

    Full Text Available Many online communities nowadays are emphasized more on peer interactions and information sharing among members; very few online communities are built with knowledge management in nature supported by knowledge management system (KMS. This study aims to present a community of practice on how to effectively adopt a knowledge management system (KMS to neutralize a cyber collaborative learning community for a research lab in a higher education setting. A longitudinal case for 7 years was used to analyze the retention and extension of participants‟ community of practice experiences. Interviews were conducted for the comparison between experiences and theories. It was found that the transformations of tacit and explicit knowledge are in accordance with the framework of Nonaka‟s model of knowledge management from which we elicit the strategies and suggestions to the adoption and implementation of virtual collaborative research community supported by KMS.

  3. Prototyping virtual cancer therapist (VCT): a software engineering approach.

    Science.gov (United States)

    Liu, S; Gaudiot, J-L; Cristini, V

    2006-01-01

    This paper proposes the virtual cancer therapist (VCT), a scalable and robust cancer expert system that makes cancer diagnosis, recommends therapy plans, and simulates therapy plans in silico. This system consists of an evaluation core that makes prognosis and chemotherapy simulations, a biomedical database that supports therapy planning, and an optimizer module that makes cancer diagnosis and produces queries for the optimal therapy plans. With the support of its patient record database and simulation core, VCT can also be used to establish an in silico drug discovery standard that dramatically reduces the drug discovery timeline and cost. The prototype of VCT presented in this paper has not only demonstrated the capability of VCT but also identified problems that need to be addressed in the next cycle of development.

  4. Virtual Reality Tumor Resection: The Force Pyramid Approach.

    Science.gov (United States)

    Sawaya, Robin; Bugdadi, Abdulgadir; Azarnoush, Hamed; Winkler-Schwartz, Alexander; Alotaibi, Fahad E; Bajunaid, Khalid; AlZhrani, Gmaan A; Alsideiri, Ghusn; Sabbagh, Abdulrahman J; Del Maestro, Rolando F

    2017-09-05

    The force pyramid is a novel visual representation allowing spatial delineation of instrument force application during surgical procedures. In this study, the force pyramid concept is employed to create and quantify dominant hand, nondominant hand, and bimanual force pyramids during resection of virtual reality brain tumors. To address 4 questions: Do ergonomics and handedness influence force pyramid structure? What are the differences between dominant and nondominant force pyramids? What is the spatial distribution of forces applied in specific tumor quadrants? What differentiates "expert" and "novice" groups regarding their force pyramids? Using a simulated aspirator in the dominant hand and a simulated sucker in the nondominant hand, 6 neurosurgeons and 14 residents resected 8 different tumors using the CAE NeuroVR virtual reality neurosurgical simulation platform (CAE Healthcare, Montréal, Québec and the National Research Council Canada, Boucherville, Québec). Position and force data were used to create force pyramids and quantify tumor quadrant force distribution. Force distribution quantification demonstrates the critical role that handedness and ergonomics play on psychomotor performance during simulated brain tumor resections. Neurosurgeons concentrate their dominant hand forces in a defined crescent in the lower right tumor quadrant. Nondominant force pyramids showed a central peak force application in all groups. Bimanual force pyramids outlined the combined impact of each hand. Distinct force pyramid patterns were seen when tumor stiffness, border complexity, and color were altered. Force pyramids allow delineation of specific tumor regions requiring greater psychomotor ability to resect. This information can focus and improve resident technical skills training.

  5. Full velocity-scalar probability density function computation of heated channel flow with wall function approach

    Science.gov (United States)

    Pozorski, Jacek; Wacławczyk, Marta; Minier, Jean-Pierre

    2003-05-01

    A joint velocity-scalar probability density function (PDF) method is presented to model and simulate turbulent flows with passive inert scalars (here temperature). The full PDF approach is applied for wall-bounded flows. In the present work, the boundary conditions are imposed in the logarithmic region and the modeling is therefore performed in the wall-function spirit. The PDF equation is solved by a Monte Carlo method and the whole approach appears as a Lagrangian simulation using stochastic particles. The purpose of the work is to analyze the behavior of classical PDF models in the near-wall region and to develop new particle boundary conditions for the velocity and scalars attached to each particle. First of all, the logarithmic region is described as an equilibrium zone and resulting analytical formulas for second-order temperature-velocity statistics , , are derived. Boundary conditions for scalars are then developed and formulated in terms of instantaneous particle variables. These results are useful to discuss consistency issues between the formulation of scalar mixing models and the statement of boundary conditions. Finally, heated channel flow is simulated with a stand-alone PDF code for two different heat-flux conditions and results are compared with available direct numerical simulation and experimental data.

  6. Conditional random slope: A new approach for estimating individual child growth velocity in epidemiological research.

    Science.gov (United States)

    Leung, Michael; Bassani, Diego G; Racine-Poon, Amy; Goldenberg, Anna; Ali, Syed Asad; Kang, Gagandeep; Premkumar, Prasanna S; Roth, Daniel E

    2017-09-10

    Conditioning child growth measures on baseline accounts for regression to the mean (RTM). Here, we present the "conditional random slope" (CRS) model, based on a linear-mixed effects model that incorporates a baseline-time interaction term that can accommodate multiple data points for a child while also directly accounting for RTM. In two birth cohorts, we applied five approaches to estimate child growth velocities from 0 to 12 months to assess the effect of increasing data density (number of measures per child) on the magnitude of RTM of unconditional estimates, and the correlation and concordance between the CRS and four alternative metrics. Further, we demonstrated the differential effect of the choice of velocity metric on the magnitude of the association between infant growth and stunting at 2 years. RTM was minimally attenuated by increasing data density for unconditional growth modeling approaches. CRS and classical conditional models gave nearly identical estimates with two measures per child. Compared to the CRS estimates, unconditional metrics had moderate correlation (r = 0.65-0.91), but poor agreement in the classification of infants with relatively slow growth (kappa = 0.38-0.78). Estimates of the velocity-stunting association were the same for CRS and classical conditional models but differed substantially between conditional versus unconditional metrics. The CRS can leverage the flexibility of linear mixed models while addressing RTM in longitudinal analyses. © 2017 The Authors American Journal of Human Biology Published by Wiley Periodicals, Inc.

  7. MODELS OF LIVE MIGRATION WITH ITERATIVE APPROACH AND MOVE OF VIRTUAL MACHINES

    Directory of Open Access Journals (Sweden)

    S. M. Aleksankov

    2015-11-01

    Full Text Available Subject of Research. The processes of live migration without shared storage with pre-copy approach and move migration are researched. Migration of virtual machines is an important opportunity of virtualization technology. It enables applications to move transparently with their runtime environments between physical machines. Live migration becomes noticeable technology for efficient load balancing and optimizing the deployment of virtual machines to physical hosts in data centres. Before the advent of live migration, only network migration (the so-called, «Move», has been used, that entails stopping the virtual machine execution while copying to another physical server, and, consequently, unavailability of the service. Method. Algorithms of live migration without shared storage with pre-copy approach and move migration of virtual machines are reviewed from the perspective of research of migration time and unavailability of services at migrating of virtual machines. Main Results. Analytical models are proposed predicting migration time of virtual machines and unavailability of services at migrating with such technologies as live migration with pre-copy approach without shared storage and move migration. In the latest works on the time assessment of unavailability of services and migration time using live migration without shared storage experimental results are described, that are applicable to draw general conclusions about the changes of time for unavailability of services and migration time, but not to predict their values. Practical Significance. The proposed models can be used for predicting the migration time and time of unavailability of services, for example, at implementation of preventive and emergency works on the physical nodes in data centres.

  8. An Islanding Microgrid Power Sharing Approach Using Enhanced Virtual Impedance Control Scheme

    DEFF Research Database (Denmark)

    He, Jinwei; Li, Yun Wei; Guerrero, Josep M.

    2013-01-01

    In order to address the load sharing problem in islanding microgrids, this paper proposes an enhanced distributed generation (DG) unit virtual impedance control approach. The proposed method can realize accurate regulation of DG unit equivalent impedance at both fundamental and selected harmonic ...... and PCC harmonic voltage compensation are achieved without using any fundamental and harmonic components extractions. Experimental results from a scaled single-phase microgrid prototype are provided to validate the feasibility of the proposed virtual impedance control approach.......In order to address the load sharing problem in islanding microgrids, this paper proposes an enhanced distributed generation (DG) unit virtual impedance control approach. The proposed method can realize accurate regulation of DG unit equivalent impedance at both fundamental and selected harmonic...... frequencies. In contrast to conventional virtual impedance control methods, where only a line current feed-forward term is added to the DG voltage reference, the proposed virtual impedance at fundamental and harmonic frequencies is regulated using DG line current and point of common coupling (PCC) voltage...

  9. Halting HIV/AIDS with avatars and havatars: a virtual world approach to modelling epidemics

    Directory of Open Access Journals (Sweden)

    Smith? Robert J

    2009-11-01

    Full Text Available Abstract Background A major deficit of all approaches to epidemic modelling to date has been the need to approximate or guess at human behaviour in disease-transmission-related contexts. Avatars are generally human-like figures in virtual computer worlds controlled by human individuals. Methods We introduce the concept of a "havatar", which is a (human, avatar pairing. Evidence is mounting that this pairing behaves in virtual contexts much like the human in the pairing might behave in analogous real-world contexts. Results We propose that studies of havatars, in a virtual world, may give a realistic approximation of human behaviour in real-world contexts. If the virtual world approximates the real world in relevant details (geography, transportation, etc., virtual epidemics in that world could accurately simulate real-world epidemics. Havatar modelling of epidemics therefore offers a complementary tool for tackling how best to halt epidemics, including perhaps HIV/AIDS, since sexual behaviour is a significant component of some virtual worlds, such as Second Life. Conclusion Havatars place the control parameters of an epidemic in the hands of each individual. By providing tools that everyone can understand and use, we could democratise epidemiology.

  10. An Approach to the Concept of a Virtual Border: Identities and Communication Spaces

    Directory of Open Access Journals (Sweden)

    Antonio García Jiménez, Ph. D

    2010-01-01

    Full Text Available This article presents an approach to the concept of a border in cyberspace, analysed as a place of communication and identity. Firstly, it explores various dimensions of the border and specifies the role of geographical boundaries. Different aspects that define virtual borders, such as changes in the concept of borders from the Internet, ideas of memory and identity, national implications, virtual communities, and relationships between the external borders and borders online are shown next. Finally, a typology of virtual boundaries is presented. Resumen: Se presenta una aproximación a la frontera en el ciberespacio entendida como un lugar de comunicación e identitario. En primer lugar, se estudian las diferentes dimensiones del hecho fronterizo y se delimita el papel que tienen las fronteras geográficas. A continuación, se destacan los aspectos que definen la frontera virtual tales como los cambios en el concepto de frontera a partir de Internet, la idea de memoria, las implicaciones nacionales e identitarias, las comunidades virtuales, o las relaciones entre las fronteras externas y las propias de Internet. Finalmente, se propone una tipología de las fronteras virtuales.

  11. Virtual field trips: exploring a new approach to ocean education

    Science.gov (United States)

    Cary, C.; Bryant, T.

    2003-04-01

    During the past four years with primary support from the National Science Foundation, the University of Delaware College of Marine Studies has launched the "Extreme series" of virtual field trips to get students and the public excited -- and learning -- about science by enabling them to follow along with researchers as they explore hydrothermal vents in the Pacific Ocean. The Extreme series has blossomed from a small pilot project involving about 800 students in 14 schools primarily in Delaware, to a thriving program that last year welcomed aboard more than 500 schools representing over 42,000 students from across the United States and in several foreign countries. Participants range from small, rural schools on American Indian reservations and in the landlocked states of America's "heartland," to large public schools in major coastal cities such as New York and Los Angeles. Each participating teacher receives a resource package containing student guides, curricula, evaluation tools, and a documentary video. During the expedition, an interactive Web site serves as the program's "lifeline." Education coordinators aboard ship -- a UD graduate student and a schoolteacher -- post daily journals, conduct experiments submitted by classrooms, and relay photos and video clips back to shore each day for uploading to the Web site. The project also involves selected classrooms in teleconferences with scientists working live on the seafloor aboard the submersible Alvin. Evaluated for its educational quality and impact, the Extreme series continues to grow and develop with the enthusiastic support of teachers.

  12. A velocity tracking approach for the data assimilation problem in blood flow simulations.

    Science.gov (United States)

    Tiago, J; Guerra, T; Sequeira, A

    2017-10-01

    Several advances have been made in data assimilation techniques applied to blood flow modeling. Typically, idealized boundary conditions, only verified in straight parts of the vessel, are assumed. We present a general approach, on the basis of a Dirichlet boundary control problem, that may potentially be used in different parts of the arterial system. The relevance of this method appears when computational reconstructions of the 3D domains, prone to be considered sufficiently extended, are either not possible, or desirable, because of computational costs. On the basis of taking a fully unknown velocity profile as the control, the approach uses a discretize then optimize methodology to solve the control problem numerically. The methodology is applied to a realistic 3D geometry representing a brain aneurysm. The results show that this data assimilation approach may be preferable to a pressure control strategy and that it can significantly improve the accuracy associated to typical solutions obtained using idealized velocity profiles. Copyright © 2016 John Wiley & Sons, Ltd.

  13. A Virtual Approach to Teaching Safety Skills to Children with Autism Spectrum Disorder

    Science.gov (United States)

    Self, Trisha; Scudder, Rosalind R.; Weheba, Gamal; Crumrine, Daiquirie

    2007-01-01

    Recent advancements in the development of hardware/software configurations for delivering virtual reality (VR) environments to individuals with disabilities have included approaches for children with autism spectrum disorder (ASD). This article describes a study comparing benefits of using VR to benefits of an integrated/visual treatment model…

  14. Putting Roman Dams in Context: a Virtual Approach

    Science.gov (United States)

    Decker, M. J.; Du Vernay, J. P.; Mcleod, J. B.

    2017-08-01

    Water resources and management have become a critical global issue. During the half-millennium of its existence, the Roman Empire developed numerous strategies to cope with water management, from large-scale urban aqueduct systems, to industrial-scale water mills designed to cope with feeding growing city populations. Roman engineers encountered, adopted, and adapted indigenous hydraulic systems, and left lasting imprints on the landscape of the Mediterranean and temperate Western Europe by employing a range of water technologies. A recent academic study has enabled the identification of remains of and references to seventy-two dams from the Roman era, constructed in Spain between the 1st and 4th century AD. Such unique heritage, without comparisons in the Mediterranean makes Spain an emblematic case study for the analysis of Roman hydraulic engineering and water management policies. Fifty dams have been located and detailed. The twenty-two outstanding, although identified on the ground, have not been able to be acceptably characterized, due in some cases to their being ruins in a highly degraded state, others due to their being masked by repairs and reconstructions subsequent to the Roman era. A good example of such neglected dams is the buttress dam of Consuegra , in Toledo province (Castilla-La Mancha). Dating to the 3rd - 4th century AD, the Dam of Consuegra, on the basin of the Guadiana, with its over 600 metres length and 4,80 metres height, is a remarkable case of Roman engineering mastery. It had a retaining wall upstream, numerous buttresses and perhaps an embankment downstream, of which no remains are left. The application of 3D digital imaging technique to create a high quality virtual model of such monuments has proved to be successful especially for the study of the technological aspects related its construction. The case study of the Roman dam of Muel (Zaragoza) has shown, in fact, as best practices in digital archaeology can provide an original and

  15. PUTTING ROMAN DAMS IN CONTEXT: A VIRTUAL APPROACH

    Directory of Open Access Journals (Sweden)

    M. J. Decker

    2017-08-01

    Full Text Available Water resources and management have become a critical global issue. During the half-millennium of its existence, the Roman Empire developed numerous strategies to cope with water management, from large-scale urban aqueduct systems, to industrial-scale water mills designed to cope with feeding growing city populations. Roman engineers encountered, adopted, and adapted indigenous hydraulic systems, and left lasting imprints on the landscape of the Mediterranean and temperate Western Europe by employing a range of water technologies. A recent academic study has enabled the identification of remains of and references to seventy-two dams from the Roman era, constructed in Spain between the 1st and 4th century AD. Such unique heritage, without comparisons in the Mediterranean makes Spain an emblematic case study for the analysis of Roman hydraulic engineering and water management policies. Fifty dams have been located and detailed. The twenty-two outstanding, although identified on the ground, have not been able to be acceptably characterized, due in some cases to their being ruins in a highly degraded state, others due to their being masked by repairs and reconstructions subsequent to the Roman era. A good example of such neglected dams is the buttress dam of Consuegra , in Toledo province (Castilla-La Mancha. Dating to the 3rd - 4th century AD, the Dam of Consuegra, on the basin of the Guadiana, with its over 600 metres length and 4,80 metres height, is a remarkable case of Roman engineering mastery. It had a retaining wall upstream, numerous buttresses and perhaps an embankment downstream, of which no remains are left. The application of 3D digital imaging technique to create a high quality virtual model of such monuments has proved to be successful especially for the study of the technological aspects related its construction. The case study of the Roman dam of Muel (Zaragoza has shown, in fact, as best practices in digital archaeology can provide

  16. Telerehabilitation and emerging virtual reality approaches to stroke rehabilitation.

    Science.gov (United States)

    Putrino, David

    2014-12-01

    Stroke is the leading cause of permanent motor disability in the United States, and the rapidly aging population makes finding large-scale treatment solutions to this problem a national priority. Telerehabilitation is an emerging approach that is being used for the effective treatment of multiple diseases, and is beginning to show promise for stroke. The purpose of this review is to identify and highlight the areas of telerehabilitation that require the most research attention. Although there are many different forms of telerehabilitation approaches being attempted for stroke, the only approach that is currently showing moderate-strong evidence for efficacy is videogame-driven telerehabilitation (VGDT). However, targeted research is still required to determine the feasibility of VGDT: metrics regarding system usability, cost-effectiveness, and data privacy concerns still require major attention. VGDT is an emerging approach that shows enormous promise for stroke rehabilitation. Future studies should focus less on developing custom task controllers and therapy games and more on developing innovative, online data acquisition and analytics pipelines, as well as understanding the patient population so that the rehabilitation experience can be better customized.

  17. Virtual Communities in Europe: The European Library Approach

    Science.gov (United States)

    Stigter, Fleur

    2009-01-01

    Purpose: The purpose of this paper is to provide an overview of The Bridging Worlds Conference which was held in October 2008 in Singapore. Design/methodology/approach: One of the main topics the National Library Board of Singapore, the organising party, wished to address was the roles cultural institutions, such as libraries, may play in…

  18. General approach to boat simulation in virtual reality systems

    Science.gov (United States)

    Aranov, Vladislav Y.; Belyaev, Sergey Y.

    2002-02-01

    The paper is dedicated to real time simulation of sport boats, particularly a kayak and high-speed skimming boat, for training goals. This training is issue of the day, since kayaking and riding a high-speed skimming boat are both extreme sports. Participating in such types of competitions puts sportsmen into danger, particularly due to rapids, waterfalls, different water streams, and other obstacles. In order to make the simulation realistic, it is necessary to calculate data for at least 30 frames per second. These calculations may take not more than 5% CPU time, because very time-consuming 3D rendering process takes the rest - 95% CPU time. This paper describes an approach for creating minimal boat simulator models that satisfy the mentioned requirements. Besides, this approach can be used for other watercraft models of this kind.

  19. Virtually teaching virtual leadership

    DEFF Research Database (Denmark)

    Henriksen, Thomas Duus; Nielsen, Rikke Kristine; Børgesen, Kenneth

    2018-01-01

    This paper seeks to investigate the challenges to virtual collaboration and leadership on basis of findings from a virtual course on collaboration and leadership. The course used for this experiment was designed as a practical approach, which allowed participants to experience curriculum phenomena....... This experimental course provided insights into the challenges involved in virtual processes, and those experiences where used for addressing the challenges that virtual leadership is confronted with. Emphasis was placed on the reduction of undesired virtual distance and its consequences through affinity building....... We found that student scepticism appeared when a breakdown resulted in increasing virtual distance, and raises questions on how leaders might translate or upgrade their understandings of leadership to handling such increased distance through affinity building....

  20. The virtual approach to the assessment of skeletal injuries in human skeletal remains of forensic importance.

    Science.gov (United States)

    Urbanová, Petra; Ross, Ann H; Jurda, Mikoláš; Šplíchalová, Ivana

    2017-07-01

    While assessing skeletal injuries in human skeletal remains, forensic anthropologists are frequently presented with fractured, fragmented, or otherwise modified skeletal remains. The examination of evidence and the mechanisms of skeletal injuries often require that separate osseous elements be permanently or temporarily reassembled or reconstructed. If not dealt with properly, such reconstructions may impede accurate interpretation of the evidence. Nowadays, routine forensic examinations increasingly incorporate digital imaging technologies. As a result, a variety of PC-assisted imaging techniques, collectively referred to as the virtual approach, have been made available to treat fragmentary skeletal remains. The present study employs a 3D virtual approach to assess mechanisms of skeletal injuries, and provides an expert opinion of causative tools in three forensic cases involving human skeletal remains where integrity was compromised by multiple peri- or postmortem alterations resulting in fragmentation and/or incompleteness. Three fragmentary skulls and an incomplete set of foot bones with evidence of perimortem fractures (gunshot wounds) and sharp force trauma (saw marks) were digitized using a desktop laser scanner. The digitized skeletal elements were reassembled in the virtual workspace using functionalities incorporated in AMIRA ® version 5.0 software, and simultaneously in real physical space by traditional reconstructive approaches. For this study, the original skeletal fragments were substituted by replicas built by 3D printing. Inter-method differences were quantified by mesh-based comparison after the physically reassembled elements had been re-digitized. Observed differences were further reinforced by visualizing local variations using colormaps and other advanced 3D visualization techniques. In addition, intra-operator and inter-operator error was computed. The results demonstrate that the importance of incorporating the virtual approach into the

  1. A Combined Raindrop Aggregate Destruction Test-Settling Tube (RADT-ST Approach to Identify the Settling Velocity of Sediment

    Directory of Open Access Journals (Sweden)

    Liangang Xiao

    2015-10-01

    Full Text Available The use of sediment settling velocity based on mineral grain size distribution in erosion models ignores the effects of aggregation on settling velocity. The alternative approach, wet-sieved aggregate size distribution, on the other hand, cannot represent all destructive processes that eroded soils may experience under impacting raindrops. Therefore, without considering raindrop impact, both methods may lead to biased predictions of the redistribution of sediment and associated substances across landscapes. Rainfall simulation is an effective way to simulate natural raindrop impact under controlled laboratory conditions. However, very few methods have been developed to integrate rainfall simulation with the settling velocity of eroded sediment. This study aims to develop a new proxy, based on rainfall simulation, in order to identify the actual settling velocity distribution of aggregated sediment. A combined Raindrop Aggregate Destruction Test-Settling Tube (RADT-ST approach was developed to (1 simulate aggregate destruction under a series of simulated rainfalls; and (2 measure the actual settling velocity distribution of destroyed aggregates. Mean Weight Settling Velocity (MWSV of aggregates was used to investigate settling behaviors of different soils as rainfall kinetic energy increased. The results show the settling velocity of silt-rich raindrop impacted aggregates is likely to be underestimated by at least six times if based on mineral grain size distribution. The RADT-ST designed in this study effectively captures the effects of aggregation on settling behavior. The settling velocity distribution should be regarded as an evolving, rather than steady state parameter during erosion events. The combined RADT-ST approach is able to generate the quasi-natural sediment under controlled simulated rainfall conditions and is adequately sensitive to measure actual settling velocities of differently aggregated soils. This combined approach provides

  2. A database of virtual healthy subjects to assess the accuracy of foot-to-foot pulse wave velocities for estimation of aortic stiffness.

    Science.gov (United States)

    Willemet, Marie; Chowienczyk, Phil; Alastruey, Jordi

    2015-08-15

    While central (carotid-femoral) foot-to-foot pulse wave velocity (PWV) is considered to be the gold standard for the estimation of aortic arterial stiffness, peripheral foot-to-foot PWV (brachial-ankle, femoral-ankle, and carotid-radial) are being studied as substitutes of this central measurement. We present a novel methodology to assess theoretically these computed indexes and the hemodynamics mechanisms relating them. We created a database of 3,325 virtual healthy adult subjects using a validated one-dimensional model of the arterial hemodynamics, with cardiac and arterial parameters varied within physiological healthy ranges. For each virtual subject, foot-to-foot PWV was computed from numerical pressure waveforms at the same locations where clinical measurements are commonly taken. Our numerical results confirm clinical observations: 1) carotid-femoral PWV is a good indicator of aortic stiffness and correlates well with aortic PWV; 2) brachial-ankle PWV overestimates aortic PWV and is related to the stiffness and geometry of both elastic and muscular arteries; and 3) muscular PWV (carotid-radial, femoral-ankle) does not capture the stiffening of the aorta and should therefore not be used as a surrogate for aortic stiffness. In addition, our analysis highlights that the foot-to-foot PWV algorithm is sensitive to the presence of reflected waves in late diastole, which introduce errors in the PWV estimates. In this study, we have created a database of virtual healthy subjects, which can be used to assess theoretically the efficiency of physiological indexes based on pulse wave analysis. Copyright © 2015 the American Physiological Society.

  3. Combining in silico and in cerebro approaches for virtual screening and pose prediction in SAMPL4

    Science.gov (United States)

    Voet, Arnout R. D.; Kumar, Ashutosh; Berenger, Francois; Zhang, Kam Y. J.

    2014-04-01

    The SAMPL challenges provide an ideal opportunity for unbiased evaluation and comparison of different approaches used in computational drug design. During the fourth round of this SAMPL challenge, we participated in the virtual screening and binding pose prediction on inhibitors targeting the HIV-1 integrase enzyme. For virtual screening, we used well known and widely used in silico methods combined with personal in cerebro insights and experience. Regular docking only performed slightly better than random selection, but the performance was significantly improved upon incorporation of additional filters based on pharmacophore queries and electrostatic similarities. The best performance was achieved when logical selection was added. For the pose prediction, we utilized a similar consensus approach that amalgamated the results of the Glide-XP docking with structural knowledge and rescoring. The pose prediction results revealed that docking displayed reasonable performance in predicting the binding poses. However, prediction performance can be improved utilizing scientific experience and rescoring approaches. In both the virtual screening and pose prediction challenges, the top performance was achieved by our approaches. Here we describe the methods and strategies used in our approaches and discuss the rationale of their performances.

  4. Combining in silico and in cerebro approaches for virtual screening and pose prediction in SAMPL4.

    Science.gov (United States)

    Voet, Arnout R D; Kumar, Ashutosh; Berenger, Francois; Zhang, Kam Y J

    2014-04-01

    The SAMPL challenges provide an ideal opportunity for unbiased evaluation and comparison of different approaches used in computational drug design. During the fourth round of this SAMPL challenge, we participated in the virtual screening and binding pose prediction on inhibitors targeting the HIV-1 integrase enzyme. For virtual screening, we used well known and widely used in silico methods combined with personal in cerebro insights and experience. Regular docking only performed slightly better than random selection, but the performance was significantly improved upon incorporation of additional filters based on pharmacophore queries and electrostatic similarities. The best performance was achieved when logical selection was added. For the pose prediction, we utilized a similar consensus approach that amalgamated the results of the Glide-XP docking with structural knowledge and rescoring. The pose prediction results revealed that docking displayed reasonable performance in predicting the binding poses. However, prediction performance can be improved utilizing scientific experience and rescoring approaches. In both the virtual screening and pose prediction challenges, the top performance was achieved by our approaches. Here we describe the methods and strategies used in our approaches and discuss the rationale of their performances.

  5. Two different approaches for creating a prescribed opposed-flow velocity field for flame spread experiments

    Directory of Open Access Journals (Sweden)

    Carmignani Luca

    2015-01-01

    Full Text Available Opposed-flow flame spread over solid fuels is a fundamental area of research in fire science. Typically combustion wind tunnels are used to generate the opposing flow of oxidizer against which a laminar flame spread occurs along the fuel samples. The spreading flame is generally embedded in a laminar boundary layer, which interacts with the strong buoyancy-induced flow to affect the mechanism of flame spread. In this work, two different approaches for creating the opposed-flow are compared. In the first approach, a vertical combustion tunnel is used where a thin fuel sample, thin acrylic or ashless filter paper, is held vertically along the axis of the test-section with the airflow controlled by controlling the duty cycles of four fans. As the sample is ignited, a flame spreads downward in a steady manner along a developing boundary layer. In the second approach, the sample is held in a movable cart placed in an eight-meter tall vertical chamber filled with air. As the sample is ignited, the cart is moved downward (through a remote-controlled mechanism at a prescribed velocity. The results from the two approaches are compared to establish the boundary layer effect on flame spread over thin fuels.

  6. Two different approaches for creating a prescribed opposed-flow velocity field for flame spread experiments

    Science.gov (United States)

    Carmignani, Luca; Celniker, Greg; Bussett, Kyle; Paolini, Christopher; Bhattacharjee, Subrata

    2015-05-01

    Opposed-flow flame spread over solid fuels is a fundamental area of research in fire science. Typically combustion wind tunnels are used to generate the opposing flow of oxidizer against which a laminar flame spread occurs along the fuel samples. The spreading flame is generally embedded in a laminar boundary layer, which interacts with the strong buoyancy-induced flow to affect the mechanism of flame spread. In this work, two different approaches for creating the opposed-flow are compared. In the first approach, a vertical combustion tunnel is used where a thin fuel sample, thin acrylic or ashless filter paper, is held vertically along the axis of the test-section with the airflow controlled by controlling the duty cycles of four fans. As the sample is ignited, a flame spreads downward in a steady manner along a developing boundary layer. In the second approach, the sample is held in a movable cart placed in an eight-meter tall vertical chamber filled with air. As the sample is ignited, the cart is moved downward (through a remote-controlled mechanism) at a prescribed velocity. The results from the two approaches are compared to establish the boundary layer effect on flame spread over thin fuels.

  7. Simulation of petrous bone drilling in subtemporal approach utilizing virtual reality system

    Directory of Open Access Journals (Sweden)

    TANG Ke

    2012-12-01

    Full Text Available Objective To evaluate the utilizing value of virtual reality technique for microanatomy of petrous bone by comparing the anatomic characteristics and data measurement between virtual reality and cadaveric head specimens in subtemporal approach. Methods CT scan data of 15 adult cadaveric heads were inputted into the Dextroscope virtual reality system to build three-dimensional model of petrous bone. Petrous bone drilling was performed on cadaveric heads and virtual reality models respectively to expose anatomic structures step by step, and the distance and angle was measured based on selected mark points. Bland-Altman method was used for the uniformity of checking. Results Visibility effect of simulation of petrous bone drilling in virtual reality system was good. The anatomical structure of facial nerve in petrous bone, greater superficial petrosal nerve, cochlea, semicircular canal, internal carotid artery and glomus jugulare, were displayed clearly. Comparative analysis between cadaveric head and virtual reality by Bland-Altman method showed that bias for distance between geniculate ganglion and start point of common osseus crus of semicircular canal bony, geniculate ganglion and vertex of cochlea, and vertex of cochlea and start point of horizontal segment of internal carotid artery in petrous bone, were 0.020, 0.020, and -0.010 respectively, and 95% confidence intervals were -0.240-0.270, -0.190-0.220, and -0.170-0.150, respectively. Good consistency was demonstrated in scatter diagram. For the limitation of visual angle in cadaveric head, the angle between internal acoustic meatus and groove of great superficial petrosal nerve and the distance between start point of common osseus crus of semicircular canal and superior margin of glomus jugulare could not be measured, while data measurement of petrous bone model in virtual reality system was convenient and quick, without limitation of visual angle. The distance between start point of common

  8. Can Virtual Museums Motivate Students? Toward a Constructivist Learning Approach

    Science.gov (United States)

    Katz, James E.; Halpern, Daniel

    2015-12-01

    This study aims to assess the effectiveness of immersive environments that have been implemented by museums to attract new visitors. Based on the frameworks introduced by telepresence and media richness theories, and following a constructivist-based learning approach, we argue that the greater the similarity of an online museum experience is to its physical counterpart, the more positive will be the observer's perception of the collection. We reason that the similarity would lead online visitors to develop greater cognitive involvement which in turn will produce more positive attitudes toward the collection. In support of this argument, we present the results of a comparative study in which 565 participants were exposed randomly to four different exhibitions: two-dimensional collections of art and aircraft museums and three-dimensional tours of similar museums. Results indicate that whereas 3D tours have a strong effect on users' intentions to visit the real museum, cognitive involvement and sense of presence mediate the association between these variables. In terms of managerial implications, our study shows that if educational professionals want to stimulate their students to visit museums, 3D tours appear to be more effective for engaging learners through a realistic-looking environment. By offering richer perceptual cues and multimodal feedback (e.g., users can view 3D objects from multiple viewpoints or zoom in/out the objects), the study suggests that participants may increase their reasoning process and become more interested in cultural content.

  9. Phase reconstruction from velocity-encoded MRI measurements – A survey of sparsity-promoting variational approaches

    KAUST Repository

    Benning, Martin

    2014-01-01

    In recent years there has been significant developments in the reconstruction of magnetic resonance velocity images from sub-sampled k-space data. While showing a strong improvement in reconstruction quality compared to classical approaches, the vast number of different methods, and the challenges in setting them up, often leaves the user with the difficult task of choosing the correct approach, or more importantly, not selecting a poor approach. In this paper, we survey variational approaches for the reconstruction of phase-encoded magnetic resonance velocity images from sub-sampled k-space data. We are particularly interested in regularisers that correctly treat both smooth and geometric features of the image. These features are common to velocity imaging, where the flow field will be smooth but interfaces between the fluid and surrounding material will be sharp, but are challenging to represent sparsely. As an example we demonstrate the variational approaches on velocity imaging of water flowing through a packed bed of solid particles. We evaluate Wavelet regularisation against Total Variation and the relatively recent second order Total Generalised Variation regularisation. We combine these regularisation schemes with a contrast enhancement approach called Bregman iteration. We verify for a variety of sampling patterns that Morozov\\'s discrepancy principle provides a good criterion for stopping the iterations. Therefore, given only the noise level, we present a robust guideline for setting up a variational reconstruction scheme for MR velocity imaging. © 2013 Elsevier Inc. All rights reserved.

  10. Rational drug design of antineoplastic agents using 3D-QSAR, cheminformatic, and virtual screening approaches.

    Science.gov (United States)

    Vucicevic, Jelica; Nikolic, Katarina; Mitchell, John B O

    2017-07-12

    Computer-Aided Drug Design has strongly accelerated the development of novel antineoplastic agents by helping in the hit identification, optimization, and evaluation. Computational approaches such as cheminformatic search, virtual screening, pharmacophore modeling, molecular docking and dynamics have been developed and applied to explain the activity of bioactive molecules, design novel agents, increase the success rate of drug research, and decrease the total costs of drug discovery. Similarity searches and virtual screening are used to identify molecules with an increased probability to interact with drug targets of interest, while the other computational approaches are applied for the design and evaluation of molecules with enhanced activity and improved safety profile. In this review are described the main in silico techniques used in rational drug design of antineoplastic agents and presented optimal combinations of computational methods for design of more efficient antineoplastic drugs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  11. Comparison of thermal, salt and dye tracing to estimate shallow flow velocities: Novel triple-tracer approach

    Science.gov (United States)

    Abrantes, João R. C. B.; Moruzzi, Rodrigo B.; Silveira, Alexandre; de Lima, João L. M. P.

    2018-02-01

    The accurate measurement of shallow flow velocities is crucial to understand and model the dynamics of sediment and pollutant transport by overland flow. In this study, a novel triple-tracer approach was used to re-evaluate and compare the traditional and well established dye and salt tracer techniques with the more recent thermal tracer technique in estimating shallow flow velocities. For this purpose a triple tracer (i.e. dyed-salted-heated water) was used. Optical and infrared video cameras and an electrical conductivity sensor were used to detect the tracers in the flow. Leading edge and centroid velocities of the tracers were measured and the correction factors used to determine the actual mean flow velocities from tracer measured velocities were compared and investigated. Experiments were carried out for different flow discharges (32-1813 ml s-1) on smooth acrylic, sand, stones and synthetic grass bed surfaces with 0.8, 4.4 and 13.2% slopes. The results showed that thermal tracers can be used to estimate shallow flow velocities, since the three techniques yielded very similar results without significant differences between them. The main advantages of the thermal tracer were that the movement of the tracer along the measuring section was more easily visible than it was in the real image videos and that it was possible to measure space-averaged flow velocities instead of only one velocity value, with the salt tracer. The correction factors used to determine the actual mean velocity of overland flow varied directly with Reynolds and Froude numbers, flow velocity and slope and inversely with flow depth and bed roughness. In shallow flows, velocity estimation using tracers entails considerable uncertainty and caution must be taken with these measurements, especially in field studies where these variables vary appreciably in space and time.

  12. Blood vector velocity estimation using an autocorrelation approach: In vivo Investigation

    DEFF Research Database (Denmark)

    Udesen, Jesper; Bachmann, Michael; Rue, Kristina

    2005-01-01

    In conventional techniques for blood velocity estimation, only the axial component of the velocity vector is found. We have previously shown that it is possible to estimate the 2-D blood velocity vector both in simulations and in flow phantom experiments using a fast and inexpensive method (the...... deg phase shift in the lateral direction. The TO method works at angles where conventional methods fails to estimate any blood movement, i.e. when the angle between the ultrasound beam and the velocity vector is approximately 90 deg. In this paper the first in-vivo color flow map (CFM) images......) The common carotid artery, 2) the common carotid artery and the jugular vein, 3) the bifurcation of the common carotid artery. In all three cases the angle between the ultrasound beams and the blood velocity vector is larger than 60 deg. i.e. the conventional Doppler velocity estimator degrades significantly...

  13. The easy ADL home: A physical-virtual approach to domestic living

    DEFF Research Database (Denmark)

    Surie, Dipak; Pederson, Thomas; Janlert, Lars-Erik

    2010-01-01

    . In this paper, we present such an approach and use it for designing a smart home intended to support Activities of Daily Living (ADL). The easy ADL home is designed based on a wearable personal server that runs a personal ADL support middleware and a set of computationally augmented everyday objects within......Smart environments worthy of the name need to capture, interpret, and support human activities that take place within their realms. Most existing efforts tend to focus on either real world activities or activities taking place in the virtual world accessed through digital devices. However...... the easy ADL home. An initial qualitative study of the system involving 20 subjects revealed a highly positive attitude (score 4.37 out of 5) towards the system's capability of co-locating and synchronizing physical and virtual events throughout the everyday activity scenarios, while classical usability...

  14. A Novel Integrating Virtual Reality Approach for the Assessment of the Attachment Behavioral System

    Directory of Open Access Journals (Sweden)

    Irene Alice Chicchi Giglioli

    2017-06-01

    Full Text Available Virtual reality (VR technology represents a novel and powerful tool for behavioral research in psychological assessment. VR provides simulated experiences able to create the sensation of undergoing real situations. Users become active participants in the virtual environment seeing, hearing, feeling, and actuating as if they were in the real world. Currently, the most psychological VR applications concern the treatment of various mental disorders but not the assessment, that it is mainly based on paper and pencil tests. The observation of behaviors is costly, labor-intensive, and it is hard to create social situations in laboratory settings, even if the observation of actual behaviors could be particularly informative. In this framework, social stressful experiences can activate various behaviors of attachment for a significant person that can help to control and soothe them to promote individual’s well-being. Social support seeking, physical proximity, and positive and negative behaviors represent the main attachment behaviors that people can carry out during experiences of distress. We proposed VR as a novel integrating approach to measure real attachment behaviors. The first studies on attachment behavioral system by VR showed the potentiality of this approach. To improve the assessment during the VR experience, we proposed virtual stealth assessment (VSA as a new method. VSA could represent a valid and novel technique to measure various psychological attributes in real-time during the virtual experience. The possible use of this method in psychology could be to generate a more complete, exhaustive, and accurate individual’s psychological evaluation.

  15. A Transverse Oscillation Approach for Estimation of Three-Dimensional Velocity Vectors, Part II: Experimental Validation

    DEFF Research Database (Denmark)

    Pihl, Michael Johannes; Stuart, Matthias Bo; Tomov, Borislav Gueorguiev

    2014-01-01

    The 3-D transverse oscillation method is investigated by estimating 3-D velocities in an experimental flowrigsystem. Measurements of the synthesized transverse oscillatingfields are presented as well. The method employs a 2-D transducer; decouples the velocity estimation; and estimates the axial,...

  16. A transverse oscillation approach for estimation of three-dimensional velocity vectors, part II: experimental validation.

    Science.gov (United States)

    Pihl, Michael Johannes; Stuart, Matthias Bo; Tomov, Borislav Gueorguiev; Rasmussen, Morten Fischer; Jensen, Jørgen Arendt

    2014-10-01

    The 3-D transverse oscillation method is investigated by estimating 3-D velocities in an experimental flow-rig system. Measurements of the synthesized transverse oscillating fields are presented as well. The method employs a 2-D transducer; decouples the velocity estimation; and estimates the axial, transverse, and elevation velocity components simultaneously. Data are acquired using a research ultrasound scanner. The velocity measurements are conducted with steady flow in sixteen different directions. For a specific flow direction with [α, ß] = [45, 15]°, the mean estimated velocity vector at the center of the vessel is (v(x), v(y), v(z)) = (33.8, 34.5, 15.2) ± (4.6, 5.0, 0.6) cm/s where the expected velocity is (34.2, 34.2, 13.0) cm/s. The velocity magnitude is 50.6 ± 5.2 cm/s with a bias of 0.7 cm/s. The flow angles α and ß are estimated as 45.6 ± 4.9° and 17.6 ± 1.0°. Subsequently, the precision and accuracy are calculated over the entire velocity profiles. On average for all direction, the relative mean bias of the velocity magnitude is -0.08%. For α and ß, the mean bias is -0.2° and -1.5°. The relative standard deviations of the velocity magnitude ranges from 8 to 16%. For the flow angles, the ranges of the mean angular deviations are 5° to 16° and 0.7° and 8°.

  17. A new approach towards image based virtual 3D city modeling by using close range photogrammetry

    Science.gov (United States)

    Singh, S. P.; Jain, K.; Mandla, V. R.

    2014-05-01

    3D city model is a digital representation of the Earth's surface and it's related objects such as building, tree, vegetation, and some manmade feature belonging to urban area. The demand of 3D city modeling is increasing day to day for various engineering and non-engineering applications. Generally three main image based approaches are using for virtual 3D city models generation. In first approach, researchers used Sketch based modeling, second method is Procedural grammar based modeling and third approach is Close range photogrammetry based modeling. Literature study shows that till date, there is no complete solution available to create complete 3D city model by using images. These image based methods also have limitations This paper gives a new approach towards image based virtual 3D city modeling by using close range photogrammetry. This approach is divided into three sections. First, data acquisition process, second is 3D data processing, and third is data combination process. In data acquisition process, a multi-camera setup developed and used for video recording of an area. Image frames created from video data. Minimum required and suitable video image frame selected for 3D processing. In second section, based on close range photogrammetric principles and computer vision techniques, 3D model of area created. In third section, this 3D model exported to adding and merging of other pieces of large area. Scaling and alignment of 3D model was done. After applying the texturing and rendering on this model, a final photo-realistic textured 3D model created. This 3D model transferred into walk-through model or in movie form. Most of the processing steps are automatic. So this method is cost effective and less laborious. Accuracy of this model is good. For this research work, study area is the campus of department of civil engineering, Indian Institute of Technology, Roorkee. This campus acts as a prototype for city. Aerial photography is restricted in many country

  18. Geospatial Google Street View with Virtual Reality: A Motivational Approach for Spatial Training Education

    Directory of Open Access Journals (Sweden)

    Carlos Carbonell-Carrera

    2017-08-01

    Full Text Available Motivation is a determining factor in the learning process, and encourages the student to participate in activities that increase their performance. Learning strategies supplemented by computer technology in a scenario-based learning environment can improve students′ motivation for spatial knowledge acquisition. In this sense, a workshop carried out with 43-second year engineering students supported by Google Street View mobile geospatial application for location-based tasks is presented, in which participants work in an immersive wayfinding 3D urban environment on virtual reality. Students use their own smartphones with Google Street View application integrated in virtual reality (VR 3D glasses with a joystick as locomotion interface. The tool to analyse the motivational factor of this pedagogical approach is the multidimensional measurement device Intrinsic Motivation Inventory with six subscales: interest, perceived competence, perceived choice, effort, tension, and value, measured on a seven point Likert scale. Scores in all subscales considered are above 4 on a scale of 7. A usability study conducted at the end of the experiment provides values above 3 on a scale of 5 in efficacy, efficiency and satisfaction. The results of the experiment carried out indicate that geospatial Google Street View application in Virtual Reality is a motivating educational purpose in the field of spatial training.

  19. Fault diagnosis of sensor networked structures with multiple faults using a virtual beam based approach

    Science.gov (United States)

    Wang, H.; Jing, X. J.

    2017-07-01

    This paper presents a virtual beam based approach suitable for conducting diagnosis of multiple faults in complex structures with limited prior knowledge of the faults involved. The ;virtual beam;, a recently-proposed concept for fault detection in complex structures, is applied, which consists of a chain of sensors representing a vibration energy transmission path embedded in the complex structure. Statistical tests and adaptive threshold are particularly adopted for fault detection due to limited prior knowledge of normal operational conditions and fault conditions. To isolate the multiple faults within a specific structure or substructure of a more complex one, a 'biased running' strategy is developed and embedded within the bacterial-based optimization method to construct effective virtual beams and thus to improve the accuracy of localization. The proposed method is easy and efficient to implement for multiple fault localization with limited prior knowledge of normal conditions and faults. With extensive experimental results, it is validated that the proposed method can localize both single fault and multiple faults more effectively than the classical trust index subtract on negative add on positive (TI-SNAP) method.

  20. The effectiveness of sequencing virtual patients with lectures in a deductive or inductive learning approach.

    Science.gov (United States)

    Marei, Hesham Fathi; Donkers, Jeroen; Al-Eraky, Mohamed Mostafa; van Merrienboer, Jeroen J G

    2017-12-01

    Virtual patients (VPs) can be sequenced with other instructional methods in different ways. To investigate the effect of sequencing VPs with lectures in a deductive approach, in comparison with an inductive approach, on students' knowledge acquisition, retention, and transfer. For two different topics, 84 out of 87 students have participated in the lecture and VP sessions. Students from female and male campuses have been randomly assigned to one of the two learning approaches (deductive and inductive), yielding four experimental groups. Each group received a lecture session and an independent VP learning activity, which either followed the lecture session in the deductive group or preceded it in the inductive group. Students were administrated knowledge acquisition and retention written tests as well as transfer tests using two new VPs. There was no significant effect for the learning approach on knowledge acquisition or retention, while for knowledge transfer, males have benefited from the inductive approach in topic 1 while in the more complex topic 2, they have benefited from the deductive approach. On the other hand, females seem to be largely unaffected by learning approach. Sequencing VPs in inductive and deductive learning approaches leads to no significant differences on students' performance when full guidance is offered in the inductive approach.

  1. Immersive virtual reality and environmental noise assessment: An innovative audio–visual approach

    Energy Technology Data Exchange (ETDEWEB)

    Ruotolo, Francesco, E-mail: francesco.ruotolo@unina2.it [Laboratory of Cognitive Science and Immersive Virtual Reality, Department of Psychology, Second University of Naples, Viale Ellittico, 31, 81100, Caserta (Italy); Maffei, Luigi, E-mail: luigi.maffei@unina2.it [Department of Architecture and Industrial Design, Second University of Naples, Abazia di S. Lorenzo, 81031, Aversa (Italy); Di Gabriele, Maria, E-mail: maria.digabriele@unina2.it [Department of Architecture and Industrial Design, Second University of Naples, Abazia di S. Lorenzo, 81031, Aversa (Italy); Iachini, Tina, E-mail: santa.iachini@unina2.it [Laboratory of Cognitive Science and Immersive Virtual Reality, Department of Psychology, Second University of Naples, Viale Ellittico, 31, 81100, Caserta (Italy); Masullo, Massimiliano, E-mail: massimiliano.masullo@unina2.it [Department of Architecture and Industrial Design, Second University of Naples, Abazia di S. Lorenzo, 81031, Aversa (Italy); Ruggiero, Gennaro, E-mail: gennaro.ruggiero@unina2.it [Laboratory of Cognitive Science and Immersive Virtual Reality, Department of Psychology, Second University of Naples, Viale Ellittico, 31, 81100, Caserta (Italy); Senese, Vincenzo Paolo, E-mail: vincenzopaolo.senese@unina2.it [Laboratory of Cognitive Science and Immersive Virtual Reality, Department of Psychology, Second University of Naples, Viale Ellittico, 31, 81100, Caserta (Italy); Psychometric Laboratory, Department of Psychology, Second University of Naples, Viale Ellittico, 31, 81100, Caserta (Italy)

    2013-07-15

    Several international studies have shown that traffic noise has a negative impact on people's health and that people's annoyance does not depend only on noise energetic levels, but rather on multi-perceptual factors. The combination of virtual reality technology and audio rendering techniques allow us to experiment a new approach for environmental noise assessment that can help to investigate in advance the potential negative effects of noise associated with a specific project and that in turn can help designers to make educated decisions. In the present study, the audio–visual impact of a new motorway project on people has been assessed by means of immersive virtual reality technology. In particular, participants were exposed to 3D reconstructions of an actual landscape without the projected motorway (ante operam condition), and of the same landscape with the projected motorway (post operam condition). Furthermore, individuals' reactions to noise were assessed by means of objective cognitive measures (short term verbal memory and executive functions) and subjective evaluations (noise and visual annoyance). Overall, the results showed that the introduction of a projected motorway in the environment can have immediate detrimental effects of people's well-being depending on the distance from the noise source. In particular, noise due to the new infrastructure seems to exert a negative influence on short term verbal memory and to increase both visual and noise annoyance. The theoretical and practical implications of these findings are discussed. -- Highlights: ► Impact of traffic noise on people's well-being depends on multi-perceptual factors. ► A multisensory virtual reality technology is used to simulate a projected motorway. ► Effects on short-term memory and auditory and visual subjective annoyance were found. ► The closer the distance from the motorway the stronger was the effect. ► Multisensory virtual reality methodologies

  2. A new approach for estimation of the axial velocity using ultrasound

    DEFF Research Database (Denmark)

    Munk, Peter; Jensen, Jørgen Arendt

    2000-01-01

    , introducing a bias. A new velocity estimator for the mean axial velocity is presented. The estimation principle is based on the 2D Fourier transform and the Radon transform. The input data are a sequence of RF data forming a 2D data input, one column for each pulse emission. A 2D segment is selected...... data for different signal/noise ratios and simulated acoustic RF responses from a 3D measurement situation with an array transducer and a tube with plug flow. The new method shows improvement with a factor of 1.5–4 on the standard deviation on the estimated mean velocity for the simulated case....

  3. Identification of LasR Ligands through a Virtual Screening Approach

    DEFF Research Database (Denmark)

    Skovstrup, Søren; Le Quement, Sebastian Thordal; Hansen, Thomas

    2013-01-01

    With the widespread occurrence of bacterial resistance to antibiotics, the development of new strategies beyond conventional treatments is a pursuit taken by public health institutions worldwide. LasR, a transcription factor that controls quorum sensing in Pseudomonas aeruginosa, has emerged...... as an attractive therapeutic target for the next generation of antimicrobial agents. In the present study, a virtual screening workflow combining pharmacophore‐ and structure‐based approaches was used to identify new LasR ligands. Five novel inducers and three inhibitors of LasR activity were validated...

  4. A fast virtual screening approach to identify structurally diverse inhibitors of trypanothione reductase.

    Science.gov (United States)

    Maccari, Giorgio; Jaeger, Timo; Moraca, Francesca; Biava, Mariangela; Flohé, Leopold; Botta, Maurizio

    2011-09-15

    Trypanothione reductase (TryR) is one of the favorite targets for those designing drugs for the treatment of Chagas disease. We present the application of a fast virtual screening approach for designing hit compounds active against TryR. Our protocol combines information derived from structurally known inhibitors and from the TryR receptor structure. Five structurally diverse hit compounds active against TryR and holding promise for the treatment of Chagas disease are reported. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. The influence of parent's body mass index on peer selection: an experimental approach using virtual reality.

    Science.gov (United States)

    Martarelli, Corinna S; Borter, Natalie; Bryjova, Jana; Mast, Fred W; Munsch, Simone

    2015-11-30

    Relatively little is known about the influence of psychosocial factors, such as familial role modeling and social network on the development and maintenance of childhood obesity. We investigated peer selection using an immersive virtual reality environment. In a virtual schoolyard, children were confronted with normal weight and overweight avatars either eating or playing. Fifty-seven children aged 7-13 participated. Interpersonal distance to the avatars, child's BMI, self-perception, eating behavior and parental BMI were assessed. Parental BMI was the strongest predictor for the children's minimal distance to the avatars. Specifically, a higher mothers' BMI was associated with greater interpersonal distance and children approached closer to overweight eating avatars. A higher father's BMI was associated with a lower interpersonal distance to the avatars. These children approached normal weight playing and overweight eating avatar peers closest. The importance of parental BMI for the child's social approach/avoidance behavior can be explained through social modeling mechanisms. Differential effects of paternal and maternal BMI might be due to gender specific beauty ideals. Interventions to promote social interaction with peer groups could foster weight stabilization or weight loss in children. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  6. A Novel Artificial Bee Colony Approach of Live Virtual Machine Migration Policy Using Bayes Theorem

    Directory of Open Access Journals (Sweden)

    Gaochao Xu

    2013-01-01

    Full Text Available Green cloud data center has become a research hotspot of virtualized cloud computing architecture. Since live virtual machine (VM migration technology is widely used and studied in cloud computing, we have focused on the VM placement selection of live migration for power saving. We present a novel heuristic approach which is called PS-ABC. Its algorithm includes two parts. One is that it combines the artificial bee colony (ABC idea with the uniform random initialization idea, the binary search idea, and Boltzmann selection policy to achieve an improved ABC-based approach with better global exploration’s ability and local exploitation’s ability. The other one is that it uses the Bayes theorem to further optimize the improved ABC-based process to faster get the final optimal solution. As a result, the whole approach achieves a longer-term efficient optimization for power saving. The experimental results demonstrate that PS-ABC evidently reduces the total incremental power consumption and better protects the performance of VM running and migrating compared with the existing research. It makes the result of live VM migration more high-effective and meaningful.

  7. A Java/CGI approach to developing a geographic virtual reality toolkit on the Internet

    Science.gov (United States)

    Huang, Bo; Lin, Hui

    2002-02-01

    A Java/common gateway interface (CGI) approach is employed to design a toolkit for interactively building up virtual environments from existing geographical information system (GIS) databases. This approach takes advantage of both the Java and CGI approaches, providing a flexible and user friendly interface, while making better use of the power of the server. It is also beneficial to the balancing of workloads on both client and server sides. A prototype, called GeoVR, has been implemented by extending ArcView Internet Map Server on its client side by the Java language and correspondingly, on its server-side by the Avenue language. The GeoVR server is responsible for generating 3D scenes in terms of parameter values sent from the Java client. The 3D scenes are then transformed to VRML models, and delivered to the WWW browser for display and navigation. This toolkit, allowing users to interact with 2D GIS data on the Internet and create perspective views from these data on the fly, illustrates how to extend an existing Internet GIS into a more powerful virtual GIS.

  8. RGMDV: An approach to requirements gathering and the management of data virtualization projects

    Science.gov (United States)

    Mousa, Ayad Hameed; Shiratuddin, Norshuhada; Bakar, Muhamad Shahbani Abu

    2015-12-01

    Data virtualization (DV) refers to a set of data stores that enable users to query, access, and manipulate data in a unified, abstracted, and encapsulated manner regardless of data location. Apart from reducing data movement, this system provides a unified, abstracted, real-time, and encapsulated view of information for query purposes. Through its provision of live, virtual data in a timely manner, the DV technique can overcome the obstacles faced by organizations and companies as a result of using other data integration techniques. The systematic planning for the period that precedes DV deployment enables organizations to avoid many challenges related to manageability, usability, data quality, and performance. DV requirements are among the most significant and challenging aspects of a DV project. In this study, an approach has been developed to gather and manage the requirements of a DV design model as an initial step in developing such projects. Expert methods are reviewed to validate and evaluate the proposed approach in terms of usability and related components; the results of this review demonstrate that the applied approaches benefit DV development projects.

  9. The early benefits of a problem-based approach to teaching social inclusion using an online virtual town.

    Science.gov (United States)

    Beadle, Mary; Santy, Julie

    2008-05-01

    This article describes the delivery of a core pre-registration nursing and midwifery module centred on social inclusion. The module was previously delivered using a classroom-based problem-based learning approach. Difficulties with this approach led to changes to the module and its delivery. Logistic issues encouraged the module team to implement a blended learning approach using a virtual town to facilitate online learning and discussion activities. The paper describes and discusses the use of online learning technology to support student nurses and midwives. It highlights the benefits of this approach and outlines some of the experiences of the students including their evaluation of the virtual town. There is also an examination of some of the practical and theoretical issues related to both problem-based learning, online working and using a virtual town to support learning. This article outlines the approach taken and its implications.

  10. Stalking the Materials Genome: A Data-Driven Approach to the Virtual Design of Nanostructured Polymers.

    Science.gov (United States)

    Breneman, Curt M; Brinson, L Catherine; Schadler, Linda S; Natarajan, Bharath; Krein, Michael; Wu, Ke; Morkowchuk, Lisa; Li, Yang; Deng, Hua; Xu, Hongyi

    2013-12-10

    Accelerated insertion of nanocomposites into advanced applications is predicated on the ability to perform a priori property predictions on the resulting materials. In this paper, a paradigm for the virtual design of spherical nanoparticle-filled polymers is demonstrated. A key component of this "Materials Genomics" approach is the development and use of Materials Quantitative Structure-Property Relationship (MQSPR) models trained on atomic-level features of nanofiller and polymer constituents and used to predict the polar and dispersive components of their surface energies. Surface energy differences are then correlated with the nanofiller dispersion morphology and filler/matrix interface properties and integrated into a numerical analysis approach that allows the prediction of thermomechanical properties of the spherical nanofilled polymer composites. Systematic experimental studies of silica nanoparticles modified with three different surface chemistries in polystyrene (PS), poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA) and poly(2-vinyl pyridine) (P2VP) are used to validate the models. While demonstrated here as effective for the prediction of meso-scale morphologies and macro-scale properties under quasi-equilibrium processing conditions, the protocol has far ranging implications for Virtual Design.

  11. Extended Endoscopic Endonasal Approaches for Cerebral Aneurysms: Anatomical, Virtual Reality and Morphometric Study

    Directory of Open Access Journals (Sweden)

    Alberto Di Somma

    2014-01-01

    Full Text Available Introduction. The purpose of the present contribution is to perform a detailed anatomic and virtual reality three-dimensional stereoscopic study in order to test the effectiveness of the extended endoscopic endonasal approaches for selected anterior and posterior circulation aneurysms. Methods. The study was divided in two main steps: (1 simulation step, using a dedicated Virtual Reality System (Dextroscope, Volume Interactions; (2 dissection step, in which the feasibility to reach specific vascular territory via the nose was verified in the anatomical laboratory. Results. Good visualization and proximal and distal vascular control of the main midline anterior and posterior circulation territory were achieved during the simulation step as well as in the dissection step (anterior communicating complex, internal carotid, ophthalmic, superior hypophyseal, posterior cerebral and posterior communicating, basilar, superior cerebellar, anterior inferior cerebellar, vertebral, and posterior inferior cerebellar arteries. Conclusion. The present contribution is intended as strictly anatomic study in which we highlighted some specific anterior and posterior circulation aneurysms that can be reached via the nose. For clinical applications of these approaches, some relevant complications, mainly related to the endonasal route, such as proximal and distal vascular control, major arterial bleeding, postoperative cerebrospinal fluid leak, and olfactory disturbances must be considered.

  12. Extended Endoscopic Endonasal Approaches for Cerebral Aneurysms: Anatomical, Virtual Reality and Morphometric Study

    Science.gov (United States)

    de Notaris, Matteo; Enseñat, Joaquim; Alobid, Isam; San Molina, Joan; Berenguer, Joan; Cappabianca, Paolo

    2014-01-01

    Introduction. The purpose of the present contribution is to perform a detailed anatomic and virtual reality three-dimensional stereoscopic study in order to test the effectiveness of the extended endoscopic endonasal approaches for selected anterior and posterior circulation aneurysms. Methods. The study was divided in two main steps: (1) simulation step, using a dedicated Virtual Reality System (Dextroscope, Volume Interactions); (2) dissection step, in which the feasibility to reach specific vascular territory via the nose was verified in the anatomical laboratory. Results. Good visualization and proximal and distal vascular control of the main midline anterior and posterior circulation territory were achieved during the simulation step as well as in the dissection step (anterior communicating complex, internal carotid, ophthalmic, superior hypophyseal, posterior cerebral and posterior communicating, basilar, superior cerebellar, anterior inferior cerebellar, vertebral, and posterior inferior cerebellar arteries). Conclusion. The present contribution is intended as strictly anatomic study in which we highlighted some specific anterior and posterior circulation aneurysms that can be reached via the nose. For clinical applications of these approaches, some relevant complications, mainly related to the endonasal route, such as proximal and distal vascular control, major arterial bleeding, postoperative cerebrospinal fluid leak, and olfactory disturbances must be considered. PMID:24575410

  13. A Layered Approach for Robust Spatial Virtual Human Pose Reconstruction Using a Still Image

    Directory of Open Access Journals (Sweden)

    Chengyu Guo

    2016-02-01

    Full Text Available Pedestrian detection and human pose estimation are instructive for reconstructing a three-dimensional scenario and for robot navigation, particularly when large amounts of vision data are captured using various data-recording techniques. Using an unrestricted capture scheme, which produces occlusions or breezing, the information describing each part of a human body and the relationship between each part or even different pedestrians must be present in a still image. Using this framework, a multi-layered, spatial, virtual, human pose reconstruction framework is presented in this study to recover any deficient information in planar images. In this framework, a hierarchical parts-based deep model is used to detect body parts by using the available restricted information in a still image and is then combined with spatial Markov random fields to re-estimate the accurate joint positions in the deep network. Then, the planar estimation results are mapped onto a virtual three-dimensional space using multiple constraints to recover any deficient spatial information. The proposed approach can be viewed as a general pre-processing method to guide the generation of continuous, three-dimensional motion data. The experiment results of this study are used to describe the effectiveness and usability of the proposed approach.

  14. Contact-based ligand-clustering approach for the identification of active compounds in virtual screening

    Directory of Open Access Journals (Sweden)

    Mantsyzov AB

    2012-09-01

    Full Text Available Alexey B Mantsyzov,1 Guillaume Bouvier,2 Nathalie Evrard-Todeschi,1 Gildas Bertho11Université Paris Descartes, Sorbonne, Paris, France; 2Institut Pasteur, Paris, FranceAbstract: Evaluation of docking results is one of the most important problems for virtual screening and in silico drug design. Modern approaches for the identification of active compounds in a large data set of docked molecules use energy scoring functions. One of the general and most significant limitations of these methods relates to inaccurate binding energy estimation, which results in false scoring of docked compounds. Automatic analysis of poses using self-organizing maps (AuPosSOM represents an alternative approach for the evaluation of docking results based on the clustering of compounds by the similarity of their contacts with the receptor. A scoring function was developed for the identification of the active compounds in the AuPosSOM clustered dataset. In addition, the AuPosSOM efficiency for the clustering of compounds and the identification of key contacts considered as important for its activity, were also improved. Benchmark tests for several targets revealed that together with the developed scoring function, AuPosSOM represents a good alternative to the energy-based scoring functions for the evaluation of docking results.Keywords: scoring, docking, virtual screening, CAR, AuPosSOM

  15. Skeleton sled velocity profiles: a novel approach to understand critical aspects of the elite athletes' start phases.

    Science.gov (United States)

    Colyer, Steffi L; Stokes, Keith A; Bilzon, James L J; Salo, Aki I T

    2017-02-28

    The development of velocity across the skeleton start is critical to performance, yet poorly understood. We aimed to understand which components of the sled velocity profile determine performance and how physical abilities influence these components. Thirteen well-trained skeleton athletes (>85% of athletes in the country) performed dry-land push-starts alongside countermovement jump and sprint tests at multiple time-points. A magnet encoder attached to the sled wheel provided velocity profiles, which were characterised using novel performance descriptors. Stepwise regression revealed four variables (pre-load velocity, pre-load distance, load effectiveness, velocity drop) to explain 99% variance in performance (β weights: 1.70, -0.81, 0.25, -0.07, respectively). Sprint times and jump ability were associated (r ± 90% CI) with pre-load velocity (-0.70 ± 0.27 and 0.88 ± 0.14, respectively) and distance (-0.48 ± 0.39 and 0.67 ± 0.29, respectively), however, unclear relationships between both physical measures and load effectiveness (0.33 ± 0.44 and -0.35 ± 0.48, respectively) were observed. Athletes should develop accelerative ability to attain higher velocity earlier on the track. Additionally, the loading phase should not be overlooked and may be more influenced by technique than physical factors. Future studies should utilise this novel approach when evaluating skeleton starts or interventions to enhance performance.

  16. Coalition of distributed generation units to virtual power players - a game theory approach

    DEFF Research Database (Denmark)

    Morais, Hugo; Sousa, Tiago M; Santos, Gabriel

    2015-01-01

    and the existence of new management players such as several types of aggregators. This paper proposes a methodology to facilitate the coalition between distributed generation units originating Virtual Power Players (VPP) considering a game theory approach. The proposed approach consists in the analysis......Smart Grids (SGs) have emerged as the new paradigm for power system operation and management, being designed to include large amounts of distributed energy resources. This new paradigm requires new Energy Resource Management (ERM) methodologies considering different operation strategies...... of the classifications that were attributed by each VPP to the distributed generation units, as well as in the analysis of the previous established contracts by each player. The proposed classification model is based in fourteen parameters including technical, economical and behavioural ones. Depending of the VPP...

  17. Minimally invasive research of presigmoidal approach for exposure of jugular foramen region utilizing virtual reality system

    Directory of Open Access Journals (Sweden)

    Ke TANG

    2015-04-01

    Full Text Available Objective To discuss minimally invasive tactics for exposure of jugular foramen region in transpetrosal-presigmoidal approach based on virtual reality image model. Methods CT and MRI scans were performed to 15 adult cadaver heads (30 sides, and image data was inputted into Vitrea virtual reality system to establish three-dimensional anatomical model of jugular foramen region. The transpetrosal-presigmoidal approach was simulated with selecting osseous landmark points to draw a cylinder. Minimally invasive simulation was performed by reducing the diameter of cylinder. Anatomic exposures in surgical trajectory following minimally invasive design were observed, measured and compared.  Results Spacial sequence of nerves and vessels of jugular foramen region was exposured clearly with the route simulating transpetrosal-presigmoidal approach. Route before and after minimally invasive design passed through the interval between vertical segment of facial nerve and sigmoid sinus. There was a part of sigmoid sinus in the route. Cerebellar hemisphere was not included in the route. Data measurement and comparative analysis showed that volume of route, petrosal osseous structure and venous sinus involved in route before minimally invasive design was more than that after minimally invasive design. The differences reached statistical significance (P = 0.000. The volumes of lower cranial nerves between routes before and after minimally invasive design did not show significant differences (P = 0.552.  Conclusions Minimally invasive route of transpetrosal-presigmoidal approach is helpful to reduce surgical injury of vital structures in effective exposure for target structures of jugular foramen region. DOI: 10.3969/j.issn.1672-6731.2015.04.011

  18. Cluster excitation and ionization in high velocity collisions:the atomic approach

    OpenAIRE

    Mezdari, Férid; Wohrer-Béroff, Karine; Chabot, Marin

    2004-01-01

    NIM; The independent atom and electron model [1] is introduced in a quantum context and associated approximations tentatively estimated. Confrontation of the model to measured ionization and excitation cross sections of small ionic carbon clusters Cn+ in collisions with helium at an impact velocity of 2.6 a.u is presented.

  19. Factors controlling floc settling velocity within San Francisco Bay, USA and comparisons with parameterisation approaches

    Science.gov (United States)

    Manning, Andrew; Schoellhamer, David

    2014-05-01

    Much of the sediment within San Francisco Bay (SFB) is cohesive and can therefore act as transport mechanism for pollutants which adsorb to clay minerals. Furthermore, muddy sediment can flocculate when resuspended; this significantly alters their transport characteristics, which poses a serious complication to the modelling of sediment pathways. The aim of this research was to determine the factors that affect floc settling velocity along a longitudinal transect in an estuary. We collected and analysed data on flocs and on potential controlling factors along a 147 km transect the length of San Francisco Bay, USA, on June 17th, 2008. The INSSEV-LF video system, which includes the novel video-based LabSFLOC instrument (developed by Manning) was used to measure floc diameters and settling velocities at 30 stations at a height of 0.7 m above the estuary bed. Floc sizes (D) ranged from 22 microns to 639 microns settling velocities (Ws) ranged between 0.04 mm/s to 15.8 mm/s during the longitudinal transect. Nearbed turbulent shear stresses throughout the transect duration were within the 0.2-0.5 Pa range which typically stimulates flocculation growth. Individual D-Ws-floc density plots suggest the suspended sediments encountered throughout SFB were composed of both mud and mixed sediment flocs. The macroflocs and microflocs (demarcation at 160 microns) sub-populations demonstrated parameterised settling velocities which spanned nearly double the range of the sample mean settling velocities (Ws_mean spanned 0.6-6 mm/s). The macroflocs tended to dominate the suspended mass (up to 77% of the ambient suspended solids concentration; SSC) from San Pablo Bay through to Carquinez Strait (the vicinity of the turbidity maximum zone). Microfloc mass was particularly significant (typically 60-100% of the SSC) in the northern section of South Bay and most of Central Bay. During slack tide, larger and faster settling flocs deposited, accounting for most of the longitudinal

  20. APPROACH TO CONSTRUCTING 3D VIRTUAL SCENE OF IRRIGATION AREA USING MULTI-SOURCE DATA

    Directory of Open Access Journals (Sweden)

    S. Cheng

    2015-10-01

    Full Text Available For an irrigation area that is often complicated by various 3D artificial ground features and natural environment, disadvantages of traditional 2D GIS in spatial data representation, management, query, analysis and visualization is becoming more and more evident. Building a more realistic 3D virtual scene is thus especially urgent for irrigation area managers and decision makers, so that they can carry out various irrigational operations lively and intuitively. Based on previous researchers' achievements, a simple, practical and cost-effective approach was proposed in this study, by adopting3D geographic information system (3D GIS, remote sensing (RS technology. Based on multi-source data such as Google Earth (GE high-resolution remote sensing image, ASTER G-DEM, hydrological facility maps and so on, 3D terrain model and ground feature models were created interactively. Both of the models were then rendered with texture data and integrated under ArcGIS platform. A vivid, realistic 3D virtual scene of irrigation area that has a good visual effect and possesses primary GIS functions about data query and analysis was constructed.Yet, there is still a long way to go for establishing a true 3D GIS for the irrigation are: issues of this study were deeply discussed and future research direction was pointed out in the end of the paper.

  1. Approach to Constructing 3d Virtual Scene of Irrigation Area Using Multi-Source Data

    Science.gov (United States)

    Cheng, S.; Dou, M.; Wang, J.; Zhang, S.; Chen, X.

    2015-10-01

    For an irrigation area that is often complicated by various 3D artificial ground features and natural environment, disadvantages of traditional 2D GIS in spatial data representation, management, query, analysis and visualization is becoming more and more evident. Building a more realistic 3D virtual scene is thus especially urgent for irrigation area managers and decision makers, so that they can carry out various irrigational operations lively and intuitively. Based on previous researchers' achievements, a simple, practical and cost-effective approach was proposed in this study, by adopting3D geographic information system (3D GIS), remote sensing (RS) technology. Based on multi-source data such as Google Earth (GE) high-resolution remote sensing image, ASTER G-DEM, hydrological facility maps and so on, 3D terrain model and ground feature models were created interactively. Both of the models were then rendered with texture data and integrated under ArcGIS platform. A vivid, realistic 3D virtual scene of irrigation area that has a good visual effect and possesses primary GIS functions about data query and analysis was constructed.Yet, there is still a long way to go for establishing a true 3D GIS for the irrigation are: issues of this study were deeply discussed and future research direction was pointed out in the end of the paper.

  2. A multi-layer cellular automata approach for algorithmic generation of virtual case studies: VIBe.

    Science.gov (United States)

    Sitzenfrei, R; Fach, S; Kinzel, H; Rauch, W

    2010-01-01

    Analyses of case studies are used to evaluate new or existing technologies, measures or strategies with regard to their impact on the overall process. However, data availability is limited and hence, new technologies, measures or strategies can only be tested on a limited number of case studies. Owing to the specific boundary conditions and system properties of each single case study, results can hardly be generalized or transferred to other boundary conditions. virtual infrastructure benchmarking (VIBe) is a software tool which algorithmically generates virtual case studies (VCSs) for urban water systems. System descriptions needed for evaluation are extracted from VIBe whose parameters are based on real world case studies and literature. As a result VIBe writes Input files for water simulation software as EPANET and EPA SWMM. With such input files numerous simulations can be performed and the results can be benchmarked and analysed stochastically at a city scale. In this work the approach of VIBe is applied with parameters according to a section of the Inn valley and therewith 1,000 VCSs are generated and evaluated. A comparison of the VCSs with data of real world case studies shows that the real world case studies fit within the parameter ranges of the VCSs. Consequently, VIBe tackles the problem of limited availability of case study data.

  3. 3D virtual character reconstruction from projections: a NURBS-based approach

    Science.gov (United States)

    Triki, Olfa; Zaharia, Titus B.; Preteux, Francoise J.

    2004-05-01

    This work has been carried out within the framework of the industrial project, so-called TOON, supported by the French government. TOON aims at developing tools for automating the traditional 2D cartoon content production. This paper presents preliminary results of the TOON platform. The proposed methodology concerns the issues of 2D/3D reconstruction from a limited number of drawn projections, and 2D/3D manipulation/deformation/refinement of virtual characters. Specifically, we show that the NURBS-based modeling approach developed here offers a well-suited framework for generating deformable 3D virtual characters from incomplete 2D information. Furthermore, crucial functionalities such as animation and non-rigid deformation can be also efficiently handled and solved. Note that user interaction is enabled exclusively in 2D by achieving a multiview constraint specification method. This is fully consistent and compliant with the cartoon creator traditional practice and makes it possible to avoid the use of 3D modeling software packages which are generally complex to manipulate.

  4. An Islanding Microgrid Power Sharing Approach Using Enhanced Virtual Impedance Control Scheme

    DEFF Research Database (Denmark)

    He, Jinwei; Li, Yun Wei; Guerrero, Josep M.

    2013-01-01

    feed-forward terms, respectively. With this modification, the impacts of mismatched physical feeder impedances are compensated. Thus, better reactive and harmonic power sharing can be realized. Additionally, this paper also demonstrates that PCC harmonic voltages can be mitigated by reducing...... the magnitude of DG unit equivalent harmonic impedance. Finally, in order to alleviate the computing load at DG unit local controller, this paper further exploits the band-pass capability of conventionally resonant controllers. With the implementation of proposed resonant controller, accurate power sharing......In order to address the load sharing problem in islanding microgrids, this paper proposes an enhanced distributed generation (DG) unit virtual impedance control approach. The proposed method can realize accurate regulation of DG unit equivalent impedance at both fundamental and selected harmonic...

  5. Three-dimensional virtual environments for cybertherapy: a psychosocial approach to effective usability.

    Science.gov (United States)

    Galimberti, Carlo; Belloni, Gloria

    2003-06-01

    The present study is to be considered in the framework of the VEPSY UPDATED project, whose main objective is to prove the technical and clinical viability of using virtual reality therapy (VRT) in clinical psychology by means of portable and shared VR systems. This contribution illustrates the attempt to elaborate a new psychosocial model of usability evaluation analysis, allowing general definitions in the context of the project, by considering areas of VR not yet completely explored from the usability point of view. The theoretical background is based upon an ethnometodological approach, a perspective that gives evidence of how people, in specific social situations, are able to solve complex tasks producing shared meanings and achieving their goals during the interactions, in order to make their actions understandable and successful.

  6. A Psychometric Tool for a Virtual Reality Rehabilitation Approach for Dyslexia

    Directory of Open Access Journals (Sweden)

    Elisa Pedroli

    2017-01-01

    Full Text Available Dyslexia is a chronic problem that affects the life of subjects and often influences their life choices. The standard rehabilitation methods all use a classic paper and pencil training format but these exercises are boring and demanding for children who may have difficulty in completing the treatments. It is important to develop a new rehabilitation program that would help children in a funny and engaging way. A Wii-based game was developed to demonstrate that a short treatment with an action video game, rather than phonological or orthographic training, may improve the reading abilities in dyslexic children. According to the results, an approach using cues in the context of a virtual environment may represent a promising tool to improve attentional skills. On the other hand, our results do not demonstrate an immediate effect on reading performance, suggesting that a more prolonged protocol may be a future direction.

  7. Virtual bronchoscopic approach for combining 3D CT and endoscopic video

    Science.gov (United States)

    Sherbondy, Anthony J.; Kiraly, Atilla P.; Austin, Allen L.; Helferty, James P.; Wan, Shu-Yen; Turlington, Janice Z.; Yang, Tao; Zhang, Chao; Hoffman, Eric A.; McLennan, Geoffrey; Higgins, William E.

    2000-04-01

    To improve the care of lung-cancer patients, we are devising a diagnostic paradigm that ties together three-dimensional (3D) high-resolution computed-tomographic (CT) imaging and bronchoscopy. The system expands upon the new concept of virtual endoscopy that has seen recent application to the chest, colon, and other anatomical regions. Our approach applies computer-graphics and image-processing tools to the analysis of 3D CT chest images and complementary bronchoscopic video. It assumes a two-stage assessment of a lung-cancer patient. During Stage 1 (CT assessment), the physician interacts with a number of visual and quantitative tools to evaluate the patient's 'virtual anatomy' (3D CT scan). Automatic analysis gives navigation paths through major airways and to pre-selected suspect sites. These paths provide useful guidance during Stage-1 CT assessment. While interacting with these paths and other software tools, the user builds a multimedia Case Study, capturing telling snapshot views, movies, and quantitative data. The Case Study contains a report on the CT scan and also provides planning information for subsequent bronchoscopic evaluation. During Stage 2 (bronchoscopy), the physician uses (1) the original CT data, (2) software graphical tools, (3) the Case Study, and (4) a standard bronchoscopy suite to have an augmented vision for bronchoscopic assessment and treatment. To use the two data sources (CT and bronchoscopic video) simultaneously, they must be registered. We perform this registration using both manual interaction and an automated matching approach based on mutual information. We demonstrate our overall progress to date using human CT cases and CT-video from a bronchoscopy- training device.

  8. Improving the spatial orientation of human teeth using a virtual 3D approach.

    Science.gov (United States)

    Benazzi, Stefano; Fantini, Massimiliano; De Crescenzio, Francesca; Persiani, Franco; Gruppioni, Giorgio

    2009-03-01

    Since teeth are resistant to decomposition processes, they provide important and at times unique sources of information about fossil humans. Fortunately, dental remains reflect significant evolutionary changes. These changes make a very important and often exclusive contribution to the definition of new taxa or the attribution of fossil specimens to existing taxa. The traditional approach to dental morphometric analyses usually focuses on the recording of several measures of the tooth with calipers, especially the two basic crown diameters (buccolingual and mesiodistal). However, since these measures do not adequately represent the complex morphology of the tooth, 2D images and 3D digital models of dental morphology have been used. For both types of analysis, the possibility of correctly comparing homologous teeth depends on the adoption of a common orientation system. The lack of such a system makes it difficult to compare the results of different studies. Here we describe a new method for orienting teeth specifically devised for the upper and lower first molar (M1). Samples of unworn maxillary (n=15) and mandibular (n=15) first molars of modern humans were scanned with a Roland Picza 3D digitizer. The 3D virtual models were used to compare our new orientation method with those proposed in the literature. The new orientation system, which meets a geometric criterion, is based on three points identified on the cervical line and ensures acceptable repeatability of the spatial positioning and orientation independent of the shape and wear of the first molar under investigation. This orientation system is a first step toward the creation of a virtual set of hominid and fossil human first molars, which will allow us to make comparisons via a sophisticated and noninvasive approach. This pilot study also provides guidelines to extend the new methodology to the other types of teeth.

  9. A Game-Based Virtualized Reality Approach for Simultaneous Rehabilitation of Motor Skill and Confidence

    Directory of Open Access Journals (Sweden)

    Alasdair G. Thin

    2012-01-01

    Full Text Available Virtualized reality games offer highly interactive and engaging user experience and therefore game-based approaches (GBVR may have significant potential to enhance clinical rehabilitation practice as traditional therapeutic exercises are often repetitive and boring, reducing patient compliance. The aim of this study was to investigate if a rehabilitation training programme using GBVR could simultaneously improve both motor skill (MS and confidence (CON, as they are both important determinants of daily living and physical and social functioning. The study was performed using a nondominant hand motor deficit model in nonambidextrous healthy young adults, whereby dominant and nondominant arms acted as control and intervention conditions, respectively. GBVR training was performed using a commercially available tennis-based game. CON and MS were assessed by having each subject perform a comparable real-world motor task (RWMT before and after training. Baseline CON and MS for performing the RWMT were significantly lower for the nondominant hand and improved after GBVR training, whereas there were no changes in the dominant (control arm. These results demonstrate that by using a GBVR approach to address a MS deficit in a real-world task, improvements in both MS and CON can be facilitated and such approaches may help increase patient compliance.

  10. Damage Based Analysis (DBA) - Theory, Derivation and Practical Application Using Both an Acceleration and Pseudo Velocity Approach

    Science.gov (United States)

    Grillo, Vince

    2017-01-01

    The objective of this presentation is to give a brief overview of the theory behind the (DBA) method, an overview of the derivation and a practical application of the theory using the Python computer language. The Theory and Derivation will use both Acceleration and Pseudo Velocity methods to derive a series of equations for processing by Python. We will take the results and compare both Acceleration and Pseudo Velocity methods and discuss implementation of the Python functions. Also, we will discuss the efficiency of the methods and the amount of computer time required for the solution. In conclusion, (DBA) offers a powerful method to evaluate the amount of energy imparted into a system in the form of both Amplitude and Duration during qualification testing and flight environments. Many forms of steady state and transient vibratory motion can be characterized using this technique. (DBA) provides a more robust alternative to traditional methods such Power Spectral Density (PSD) using a maximax approach.

  11. Damage Based Analysis (DBA): Theory, Derivation and Practical Application - Using Both an Acceleration and Pseudo-Velocity Approach

    Science.gov (United States)

    Grillo, Vince

    2016-01-01

    The objective of this presentation is to give a brief overview of the theory behind the (DBA) method, an overview of the derivation and a practical application of the theory using the Python computer language. The Theory and Derivation will use both Acceleration and Pseudo Velocity methods to derive a series of equations for processing by Python. We will take the results and compare both Acceleration and Pseudo Velocity methods and discuss implementation of the Python functions. Also, we will discuss the efficiency of the methods and the amount of computer time required for the solution. In conclusion, (DBA) offers a powerful method to evaluate the amount of energy imparted into a system in the form of both Amplitude and Duration during qualification testing and flight environments. Many forms of steady state and transient vibratory motion can be characterized using this technique. (DBA) provides a more robust alternative to traditional methods such Power Spectral Density (PSD) using a Maximax approach.

  12. Trust and virtual worlds

    DEFF Research Database (Denmark)

    Ess, Charles; Thorseth, May

    2011-01-01

    We collect diverse philosophical analyses of the issues and problems clustering around trust online with specific attention to establishing trust in virtual environments. The book moves forward important discussions of how virtual worlds and virtuality are to be defined and understood; the role...... by virtuality, such as virtual child pornography. The introduction further develops a philosophical anthropology, rooted in Kantian ethics, phenomenology, virtue ethics, and feminist perspectives, that grounds a specific approach to ethical issues in virtual environments....

  13. Design of new plasmepsin inhibitors: a virtual high throughput screening approach on the EGEE grid.

    Science.gov (United States)

    Kasam, Vinod; Zimmermann, Marc; Maass, Astrid; Schwichtenberg, Horst; Wolf, Antje; Jacq, Nicolas; Breton, Vincent; Hofmann-Apitius, Martin

    2007-01-01

    Though different species of the genus Plasmodium may be responsible for malaria, the variant caused by P. falciparum is often very dangerous and even fatal if untreated. Hemoglobin degradation is one of the key metabolic processes for the survival of the Plasmodium parasite in its host. Plasmepsins, a family of aspartic proteases encoded by the Plasmodium genome, play a prominent role in host hemoglobin cleavage. In this paper we demonstrate the use of virtual screening, in particular molecular docking, employed at a very large scale to identify novel inhibitors for plasmepsins II and IV. A large grid infrastructure, the EGEE grid, was used to address the problem of large computation resources required for docking hundreds of thousands of chemical compounds on different plasmepsin targets of P. falciparum. A large compound library of about 1 million chemical compounds was docked on 5 different targets of plasmepsins using two different docking software, namely FlexX and AutoDock. Several strategies were employed to analyze the results of this virtual screening approach including docking scores, ideal binding modes, and interactions to key residues of the protein. Three different classes of structures with thiourea, diphenylurea, and guanidino scaffolds were identified to be promising hits. While the identification of diphenylurea compounds is in accordance with the literature and thus provides a sort of "positive control", the identification of novel compounds with a guanidino scaffold proves that high throughput docking can be effectively used to identify novel potential inhibitors of P. falciparum plasmepsins. Thus, with the work presented here, we do not only demonstrate the relevance of computational grids in drug discovery but also identify several promising small molecules which have the potential to serve as candidate inhibitors for P. falciparum plasmepsins. With the use of the EGEE grid infrastructure for the virtual screening campaign against the malaria

  14. An integrated approach to distance learning with digital video in the French-speaking Virtual Medical University.

    Science.gov (United States)

    Dufour, J C; Cuggia, M; Soula, G; Spector, M; Kohler, F

    2007-01-01

    The aim of the French-speaking Virtual Medical University project (UMVF) is to share common resources and specific tools in order to improve medical training. Digital video on IP is an attractive tool for higher education but there are a number of obstacles to widespread implementation. This paper describes the UMVF approach to integrating digital video technologies and services in educational projects.

  15. Integrated Computational Approach for Virtual Hit Identification against Ebola Viral Proteins VP35 and VP40

    Directory of Open Access Journals (Sweden)

    Muhammad Usman Mirza

    2016-10-01

    Full Text Available The Ebola virus (EBOV has been recognised for nearly 40 years, with the most recent EBOV outbreak being in West Africa, where it created a humanitarian crisis. Mortalities reported up to 30 March 2016 totalled 11,307. However, up until now, EBOV drugs have been far from achieving regulatory (FDA approval. It is therefore essential to identify parent compounds that have the potential to be developed into effective drugs. Studies on Ebola viral proteins have shown that some can elicit an immunological response in mice, and these are now considered essential components of a vaccine designed to protect against Ebola haemorrhagic fever. The current study focuses on chemoinformatic approaches to identify virtual hits against Ebola viral proteins (VP35 and VP40, including protein binding site prediction, drug-likeness, pharmacokinetic and pharmacodynamic properties, metabolic site prediction, and molecular docking. Retrospective validation was performed using a database of non-active compounds, and early enrichment of EBOV actives at different false positive rates was calculated. Homology modelling and subsequent superimposition of binding site residues on other strains of EBOV were carried out to check residual conformations, and hence to confirm the efficacy of potential compounds. As a mechanism for artefactual inhibition of proteins through non-specific compounds, virtual hits were assessed for their aggregator potential compared with previously reported aggregators. These systematic studies have indicated that a few compounds may be effective inhibitors of EBOV replication and therefore might have the potential to be developed as anti-EBOV drugs after subsequent testing and validation in experiments in vivo.

  16. An Energy-Efficient Approach to Enhance Virtual Sensors Provisioning in Sensor Clouds Environments.

    Science.gov (United States)

    Lemos, Marcus Vinícius de S; Filho, Raimir Holanda; Rabêlo, Ricardo de Andrade L; de Carvalho, Carlos Giovanni N; Mendes, Douglas Lopes de S; Costa, Valney da Gama

    2018-02-26

    Virtual sensors provisioning is a central issue for sensors cloud middleware since it is responsible for selecting physical nodes, usually from Wireless Sensor Networks (WSN) of different owners, to handle user's queries or applications. Recent works perform provisioning by clustering sensor nodes based on the correlation measurements and then selecting as few nodes as possible to preserve WSN energy. However, such works consider only homogeneous nodes (same set of sensors). Therefore, those works are not entirely appropriate for sensor clouds, which in most cases comprises heterogeneous sensor nodes. In this paper, we propose ACxSIMv2, an approach to enhance the provisioning task by considering heterogeneous environments. Two main algorithms form ACxSIMv2. The first one, ACASIMv1, creates multi-dimensional clusters of sensor nodes, taking into account the measurements correlations instead of the physical distance between nodes like most works on literature. Then, the second algorithm, ACOSIMv2, based on an Ant Colony Optimization system, selects an optimal set of sensors nodes from to respond user's queries while attending all parameters and preserving the overall energy consumption. Results from initial experiments show that the approach reduces significantly the sensor cloud energy consumption compared to traditional works, providing a solution to be considered in sensor cloud scenarios.

  17. On computational approaches for size-and-shape distributions from sedimentation velocity analytical ultracentrifugation.

    Science.gov (United States)

    Schuck, Peter

    2010-07-01

    Sedimentation velocity analytical ultracentrifugation has become a very popular technique to study size distributions and interactions of macromolecules. Recently, a method termed two-dimensional spectrum analysis (2DSA) for the determination of size-and-shape distributions was described by Demeler and colleagues (Eur Biophys J 2009). It is based on novel ideas conceived for fitting the integral equations of the size-and-shape distribution to experimental data, illustrated with an example but provided without proof of the principle of the algorithm. In the present work, we examine the 2DSA algorithm by comparison with the mathematical reference frame and simple well-known numerical concepts for solving Fredholm integral equations, and test the key assumptions underlying the 2DSA method in an example application. While the 2DSA appears computationally excessively wasteful, key elements also appear to be in conflict with mathematical results. This raises doubts about the correctness of the results from 2DSA analysis.

  18. A Firefly Colony and Its Fuzzy Approach for Server Consolidation and Virtual Machine Placement in Cloud Datacenters

    Directory of Open Access Journals (Sweden)

    Boominathan Perumal

    2016-01-01

    Full Text Available Managing cloud datacenters is the most prevailing challenging task ahead for the IT industries. The data centers are considered to be the main source for resource provisioning to the cloud users. Managing these resources to handle large number of virtual machine requests has created the need for heuristic optimization algorithms to provide the optimal placement strategies satisfying the objectives and constraints formulated. In this paper, we propose to apply firefly colony and fuzzy firefly colony optimization algorithms to solve two key issues of datacenters, namely, server consolidation and multiobjective virtual machine placement problem. The server consolidation aims to minimize the count of physical machines used and the virtual machine placement problem is to obtain optimal placement strategy with both minimum power consumption and resource wastage. The proposed techniques exhibit better performance than the heuristics and metaheuristic approaches considered in terms of server consolidation and finding optimal placement strategy.

  19. A Service-Oriented Approach for Dynamic Chaining of Virtual Network Functions over Multi-Provider Software-Defined Networks

    Directory of Open Access Journals (Sweden)

    Barbara Martini

    2016-06-01

    Full Text Available Emerging technologies such as Software-Defined Networks (SDN and Network Function Virtualization (NFV promise to address cost reduction and flexibility in network operation while enabling innovative network service delivery models. However, operational network service delivery solutions still need to be developed that actually exploit these technologies, especially at the multi-provider level. Indeed, the implementation of network functions as software running over a virtualized infrastructure and provisioned on a service basis let one envisage an ecosystem of network services that are dynamically and flexibly assembled by orchestrating Virtual Network Functions even across different provider domains, thereby coping with changeable user and service requirements and context conditions. In this paper we propose an approach that adopts Service-Oriented Architecture (SOA technology-agnostic architectural guidelines in the design of a solution for orchestrating and dynamically chaining Virtual Network Functions. We discuss how SOA, NFV, and SDN may complement each other in realizing dynamic network function chaining through service composition specification, service selection, service delivery, and placement tasks. Then, we describe the architecture of a SOA-inspired NFV orchestrator, which leverages SDN-based network control capabilities to address an effective delivery of elastic chains of Virtual Network Functions. Preliminary results of prototype implementation and testing activities are also presented. The benefits for Network Service Providers are also described that derive from the adaptive network service provisioning in a multi-provider environment through the orchestration of computing and networking services to provide end users with an enhanced service experience.

  20. Lead identification for the K-Ras protein: virtual screening and combinatorial fragment-based approaches

    Directory of Open Access Journals (Sweden)

    Pathan AAK

    2016-05-01

    Full Text Available Akbar Ali Khan Pathan,1,2,* Bhavana Panthi,3,* Zahid Khan,1 Purushotham Reddy Koppula,4–6 Mohammed Saud Alanazi,1 Sachchidanand,3 Narasimha Reddy Parine,1 Mukesh Chourasia3,* 1Genome Research Chair (GRC, Department of Biochemistry, College of Science, King Saud University, 2Integrated Gulf Biosystems, Riyadh, Kingdom of Saudi Arabia; 3Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research, Hajipur, India; 4Department of Internal Medicine, School of Medicine, 5Harry S. Truman Memorial Veterans Affairs Hospital, 6Department of Radiology, School of Medicine, Columbia, MO, USA *These authors contributed equally to this work Objective: Kirsten rat sarcoma (K-Ras protein is a member of Ras family belonging to the small guanosine triphosphatases superfamily. The members of this family share a conserved structure and biochemical properties, acting as binary molecular switches. The guanosine triphosphate-bound active K-Ras interacts with a range of effectors, resulting in the stimulation of downstream signaling pathways regulating cell proliferation, differentiation, and apoptosis. Efforts to target K-Ras have been unsuccessful until now, placing it among high-value molecules against which developing a therapy would have an enormous impact. K-Ras transduces signals when it binds to guanosine triphosphate by directly binding to downstream effector proteins, but in case of guanosine diphosphate-bound conformation, these interactions get disrupted. Methods: In the present study, we targeted the nucleotide-binding site in the “on” and “off” state conformations of the K-Ras protein to find out suitable lead compounds. A structure-based virtual screening approach has been used to screen compounds from different databases, followed by a combinatorial fragment-based approach to design the apposite lead for the K-Ras protein. Results: Interestingly, the designed compounds exhibit a binding preference for the

  1. Virtual Labs and Virtual Worlds

    Science.gov (United States)

    Boehler, Ted

    2006-12-01

    Virtual Labs and Virtual Worlds Coastline Community College has under development several virtual lab simulations and activities that range from biology, to language labs, to virtual discussion environments. Imagine a virtual world that students enter online, by logging onto their computer from home or anywhere they have web access. Upon entering this world they select a personalized identity represented by a digitized character (avatar) that can freely move about, interact with the environment, and communicate with other characters. In these virtual worlds, buildings, gathering places, conference rooms, labs, science rooms, and a variety of other “real world” elements are evident. When characters move about and encounter other people (players) they may freely communicate. They can examine things, manipulate objects, read signs, watch video clips, hear sounds, and jump to other locations. Goals of critical thinking, social interaction, peer collaboration, group support, and enhanced learning can be achieved in surprising new ways with this innovative approach to peer-to-peer communication in a virtual discussion world. In this presentation, short demos will be given of several online learning environments including a virtual biology lab, a marine science module, a Spanish lab, and a virtual discussion world. Coastline College has been a leader in the development of distance learning and media-based education for nearly 30 years and currently offers courses through PDA, Internet, DVD, CD-ROM, TV, and Videoconferencing technologies. Its distance learning program serves over 20,000 students every year. sponsor Jerry Meisner

  2. Having belief(s) in social virtual worlds: A decomposed approach

    NARCIS (Netherlands)

    Merikivi, J.; Verhagen, T.; Feldberg, J.F.M.

    2013-01-01

    The interest in social virtual worlds with multiple functions has mushroomed during the past few years. The key challenge social virtual worlds face while attempting to anchor and serve the masses is to reflect the core beliefs of their users. As existing research lacks insight into these core

  3. Muscle Contraction Velocity: A Suitable Approach to Analyze the Functional Adaptations in Elite Soccer Players

    Science.gov (United States)

    Loturco, Irineu; Pereira, Lucas A.; Kobal, Ronaldo; Kitamura, Katia; Ramírez-Campillo, Rodrigo; Zanetti, Vinicius; Abad, Cesar C. Cal; Nakamura, Fabio Y.

    2016-01-01

    Tensiomyography (TMG) has been used as a simple and non-invasive tool to assess the mechanical properties of skeletal muscles. The TMG-derived velocity of contraction (Vc), which can be calculated from the ratio between maximal radial displacement and the sum of contraction time and delay time, has been proposed for evaluating athletes. However, its sensitivity to training effects and possible relation with changes in soccer players’ neuromuscular performance have not yet been addressed. To test this possibility, twenty-two male Brazilian elite soccer players were assessed using TMG-derived Vc, unloaded squat jump, countermovement jump and drop jump at 45 cm, loaded jump squat and linear (20 m) and change of direction (COD) sprint tests, prior to and after an 8-week period, between two consecutive official tournaments, during which the concurrency between endurance and strength-power training commonly impairs neuromuscular capacities. Magnitude-based inference was used to detect meaningful training effects. From pre- to post-tests, it was observed likely to almost certainly improvements in all modes of jumping tests. In addition, we could verify decrements in the 20-m and COD sprint performances, which were rated as very likely and almost certainly, respectively. Finally, both rectus femoris and biceps femoris muscles presented a likely reduction in Vc. Therefore, chronic decreases in sprinting speed are possibly accompanied by a reduced TMG-derived Vc. From a practical standpoint, the TMG-derived Vc can be used to monitor negative specific-soccer training effects related to potential impairments in maximum speed. Key points Tensiomyography (TMG) can be considered a useful technology for coaches and sport scientists seeking for non-invasive and practical tools to assess the muscle function of elite athletes; Velocity of contraction (Vc) is a single index able to integrate several of the reliable mechanical outcomes provided by TMG, which was shown to be sensitive

  4. Using a Virtual Globe approach in teaching soils and soil degradation

    Science.gov (United States)

    Cammeraat, Erik; Seijmonsbergen, Harry

    2013-04-01

    Soils are crucial to sustain our lives and therefor their origin, use and potential vulnerability are important to understand. Any graduate in an education program focusing on the "Earth's Critical Zone" should have a basic understanding of soils. We present here an instruction lecture, which is developed for the bachelor programs Earth Sciences as well Future Planet Studies as taught at the University of Amsterdam. The aim of the instruction lecture is to 1. improve learning efficiency by interactively illustrating concepts of soil formation and soil degradation on the Virtual Globe and 2. recognize their spatial distribution in a Virtual Globe environment in which known point information on soil (profiles) can be studied in their spatial context. When using historic imagery, (change in) landscape and land-use patterns can be studied in relation to soil development. We developed the instruction lecture within Google Earth and use this in a studio class room where presentations and additional non-digital techniques or experiments can be combined. We selected a case study from SE Spain, where field data are combined with remote sensing imagery and (historic) aerial photography, as well as thematic maps and other background information. This information is stored in .kmz files, which can be opened in Google Earth. Questions and assignments have been included, pinned to specific sites, landscape cross sections or regions of interest. These assignment have to be finished during the session, but can also be interactively be discussed in the classroom with the whole group of students. Such an approach can also be implemented within the preparation of field classes, which potentially improves learning efficiency. This is also important as field classes are more and more perceived as expensive, resulting in an increased pressure by the educational management to reduce in field classes. Also outcomes of research or field classes can be connected to the system by which a

  5. The Fundamentals of iSPARQL: A Virtual Triple Approach for Similarity-Based Semantic Web Tasks

    Science.gov (United States)

    Kiefer, Christoph; Bernstein, Abraham; Stocker, Markus

    This research explores three SPARQL-based techniques to solve Semantic Web tasks that often require similarity measures, such as semantic data integration, ontology mapping, and Semantic Web service matchmaking. Our aim is to see how far it is possible to integrate customized similarity functions (CSF) into SPARQL to achieve good results for these tasks. Our first approach exploits virtual triples calling property functions to establish virtual relations among resources under comparison; the second approach uses extension functions to filter out resources that do not meet the requested similarity criteria; finally, our third technique applies new solution modifiers to post-process a SPARQL solution sequence. The semantics of the three approaches are formally elaborated and discussed. We close the paper with a demonstration of the usefulness of our iSPARQL framework in the context of a data integration and an ontology mapping experiment.

  6. Rotor cage fault diagnosis in three-phase induction motors based on a current and virtual flux approach

    Energy Technology Data Exchange (ETDEWEB)

    Pires, Dulce F. [Escola Sup. Tecnologia Setubal/Inst. Politecnico Setubal, Setubal (Portugal); Pires, V. Fernao [Escola Sup. Tecnologia Setubal/Inst. Politecnico Setubal, Setubal (Portugal)]|[LabSEI - Laboratorio de Sistemas Electricos Industriais, Setubal (Portugal); Martins, J.F. [CTS, Faculdade de Ciencias e Tecnologia/UNL, Lisboa (Portugal); Pires, A.J. [Escola Sup. Tecnologia Setubal/Inst. Politecnico Setubal, Setubal (Portugal)]|[LabSEI - Laboratorio de Sistemas Electricos Industriais, Setubal (Portugal)]|[CTS, Faculdade de Ciencias e Tecnologia/UNL, Lisboa (Portugal)

    2009-04-15

    This paper focuses on the detection of a rotor cage fault in a three-phase PWM feed induction motor. In inverter-fed machines there are some difficulties for the detection of a rotor cage fault. These difficulties are due to the fault signature that will be contained in the currents or voltages applied to the machine. In this way, a new approach based on the current and a virtual flux is proposed. The use of the virtual flux allows the improving of the signal to noise ratio. This approach also allows the identification of a rotor cage fault independently of the type of control used in the ac drive. The theoretical principle of this method is discussed. Simulation and experimental results are presented in order to show the effectiveness of the proposed approach. (author)

  7. Pervasive Radio Mapping of Industrial Environments Using a Virtual Reality Approach

    Directory of Open Access Journals (Sweden)

    Adrian-Valentin Nedelcu

    2015-01-01

    Full Text Available Wireless communications in industrial environments are seriously affected by reliability and performance issues, due to the multipath nature of obstacles within such environments. Special attention needs to be given to planning a wireless industrial network, so as to find the optimum spatial position for each of the nodes within the network, and especially for key nodes such as gateways or cluster heads. The aim of this paper is to present a pervasive radio mapping system which captures (senses data regarding the radio spectrum, using low-cost wireless sensor nodes. This data is the input of radio mapping algorithms that generate electromagnetic propagation profiles. Such profiles are used for identifying obstacles within the environment and optimum propagation pathways. With the purpose of further optimizing the radio planning process, the authors propose a novel human-network interaction (HNI paradigm that uses 3D virtual environments in order to display the radio maps in a natural, easy-to-perceive manner. The results of this approach illustrate its added value to the field of radio resource planning of industrial communication systems.

  8. The recommender system for virtual items in MMORPGs based on a novel collaborative filtering approach

    Science.gov (United States)

    Li, S. G.; Shi, L.

    2014-10-01

    The recommendation system for virtual items in massive multiplayer online role-playing games (MMORPGs) has aroused the interest of researchers. Of the many approaches to construct a recommender system, collaborative filtering (CF) has been the most successful one. However, the traditional CFs just lure customers into the purchasing action and overlook customers' satisfaction, moreover, these techniques always suffer from low accuracy under cold-start conditions. Therefore, a novel collaborative filtering (NCF) method is proposed to identify like-minded customers according to the preference similarity coefficient (PSC), which implies correlation between the similarity of customers' characteristics and the similarity of customers' satisfaction level for the product. Furthermore, the analytic hierarchy process (AHP) is used to determine the relative importance of each characteristic of the customer and the improved ant colony optimisation (IACO) is adopted to generate the expression of the PSC. The IACO creates solutions using the Markov random walk model, which can accelerate the convergence of algorithm and prevent prematurity. For a target customer whose neighbours can be found, the NCF can predict his satisfaction level towards the suggested products and recommend the acceptable ones. Under cold-start conditions, the NCF will generate the recommendation list by excluding items that other customers prefer.

  9. Colonoscopy procedure simulation: virtual reality training based on a real time computational approach.

    Science.gov (United States)

    Wen, Tingxi; Medveczky, David; Wu, Jackie; Wu, Jianhuang

    2018-01-25

    Colonoscopy plays an important role in the clinical screening and management of colorectal cancer. The traditional 'see one, do one, teach one' training style for such invasive procedure is resource intensive and ineffective. Given that colonoscopy is difficult, and time-consuming to master, the use of virtual reality simulators to train gastroenterologists in colonoscopy operations offers a promising alternative. In this paper, a realistic and real-time interactive simulator for training colonoscopy procedure is presented, which can even include polypectomy simulation. Our approach models the colonoscopy as thick flexible elastic rods with different resolutions which are dynamically adaptive to the curvature of the colon. More material characteristics of this deformable material are integrated into our discrete model to realistically simulate the behavior of the colonoscope. We present a simulator for training colonoscopy procedure. In addition, we propose a set of key aspects of our simulator that give fast, high fidelity feedback to trainees. We also conducted an initial validation of this colonoscopic simulator to determine its clinical utility and efficacy.

  10. Pervasive Radio Mapping of Industrial Environments Using a Virtual Reality Approach

    Science.gov (United States)

    Nedelcu, Adrian-Valentin; Machedon-Pisu, Mihai; Talaba, Doru

    2015-01-01

    Wireless communications in industrial environments are seriously affected by reliability and performance issues, due to the multipath nature of obstacles within such environments. Special attention needs to be given to planning a wireless industrial network, so as to find the optimum spatial position for each of the nodes within the network, and especially for key nodes such as gateways or cluster heads. The aim of this paper is to present a pervasive radio mapping system which captures (senses) data regarding the radio spectrum, using low-cost wireless sensor nodes. This data is the input of radio mapping algorithms that generate electromagnetic propagation profiles. Such profiles are used for identifying obstacles within the environment and optimum propagation pathways. With the purpose of further optimizing the radio planning process, the authors propose a novel human-network interaction (HNI) paradigm that uses 3D virtual environments in order to display the radio maps in a natural, easy-to-perceive manner. The results of this approach illustrate its added value to the field of radio resource planning of industrial communication systems. PMID:26167533

  11. Ethical approach to digital skills. Sense and use in virtual educational spaces

    Directory of Open Access Journals (Sweden)

    Juan GARCÍA-GUTIÉRREZ

    2013-12-01

    Full Text Available In the context of technology and cyberspace, should we do everything we can do? The answer given to this question is not ethical, is political: safety. The safety and security are overshadowing the ethical question about the meaning of technology. Cyberspace imposes a "new logic" and new forms of "ownership". When it comes to the Internet in relation to children not always adopt logic of accountability to the cyberspace, Internet showing a space not only ethical and technical. We talk about safe Internet, Internet healthy, and Internet Fit for Children... why not talk over Internet ethics? With this work we approach digital skills as those skills that help us to position ourselves and guide us in cyberspace. Something that is not possible without also ethical skills. So, in this article we will try to build and propose a model for analyzing the virtual learning spaces (and cyberspace in general based on the categories of "use" and "sense" as different levels of ownership that indicate the types of competences needed to access cyberspace.  

  12. A Virtual Restoration Approach for Ancient Plank Road Using Mechanical Analysis with Precision 3D Data of Heritage Site

    Directory of Open Access Journals (Sweden)

    Siliang Chen

    2016-10-01

    Full Text Available The ancient plank road is a creative building in the history of Chinese ancient traffic through cliffs. In this paper, a virtual restoration approach for ancient plank road using mechanical analysis with precision 3D data of current heritage site is proposed. Firstly, an aero photogrammetry with multiple view images from Unmanned Aerial Vehicle (UAV imaging system is presented to obtain the 3D point cloud of ancient plank roads, which adopts a density image matching and aerial triangulation processing. In addition, a terrestrial laser scanner is integrated to obtain detail 3D data of the plank road. Secondly, a mechanical analysis method based on the precision 3D data of the current plank roads is proposed to determine their forms and restore each of their components with detail sizes. Finally, all components and background scene were added to the existing model to obtain a virtual restoration model, which indicates that it is effective and feasible to achieve a three-dimensional digital and virtual restoration of ancient sites. The Chiya Plank Road is taken as a virtual restoration example with the proposed approach. The restored 3D model of the ancient plank can be widely used for digital management, research, and visualization of ancient plank roads.

  13. Muscle Contraction Velocity: A Suitable Approach to Analyze the Functional Adaptations in Elite Soccer Players

    Directory of Open Access Journals (Sweden)

    Irineu Loturco, Lucas A. Pereira, Ronaldo Kobal, Katia Kitamura, Rodrigo Ramírez-Campillo, Vinicius Zanetti, Cesar C. Cal Abad, Fabio Y. Nakamura

    2016-09-01

    Full Text Available Tensiomyography (TMG has been used as a simple and non-invasive tool to assess the mechanical properties of skeletal muscles. The TMG-derived velocity of contraction (Vc, which can be calculated from the ratio between maximal radial displacement and the sum of contraction time and delay time, has been proposed for evaluating athletes. However, its sensitivity to training effects and possible relation with changes in soccer players’ neuromuscular performance have not yet been addressed. To test this possibility, twenty-two male Brazilian elite soccer players were assessed using TMG-derived Vc, unloaded squat jump, countermovement jump and drop jump at 45 cm, loaded jump squat and linear (20 m and change of direction (COD sprint tests, prior to and after an 8-week period, between two consecutive official tournaments, during which the concurrency between endurance and strength-power training commonly impairs neuromuscular capacities. Magnitude-based inference was used to detect meaningful training effects. From pre- to post-tests, it was observed likely to almost certainly improvements in all modes of jumping tests. In addition, we could verify decrements in the 20-m and COD sprint performances, which were rated as very likely and almost certainly, respectively. Finally, both rectus femoris and biceps femoris muscles presented a likely reduction in Vc. Therefore, chronic decreases in sprinting speed are possibly accompanied by a reduced TMG-derived Vc. From a practical standpoint, the TMG-derived Vc can be used to monitor negative specific-soccer training effects related to potential impairments in maximum speed.

  14. Approaching Authentic Assessment: Using Virtual School Teachers' Expertise to Develop an Understanding of Full Time K-8 Virtual School Teacher Practices

    Science.gov (United States)

    Seamster, Christina Lambert

    2016-01-01

    According to Molnar (2014), full time virtual school education lacks a measurement tool that accurately measures effective virtual teacher practice. Using both qualitative and quantitative methods, the current study sought to understand the common practices among full time K-8 virtual school teachers, the extent to which teachers believed such…

  15. Semantic Parameters to Manage an Innovation Network Using Managing as Designing Approach: The Virtual Innovation Society Network Case

    Directory of Open Access Journals (Sweden)

    Cristiane Chaves Gattaz

    2014-06-01

    Full Text Available The most recent operations and management frameworks in innovation have not been complete to explicit required knowledge to manage the cooperation of its networked open innovation value chain in the knowledge economy and open enterprise. Strategic actors from the Virtual Innovation Society network were interviewed to identify critical semantic parameters that address this issue. As a result, this study suggests the characterization of inter-dependent added-values and its performance metrics, under the “managing as designing” approach, as input for managing the externalities, the integration of the articulation between business operations, strategy and information technology, and waste of innovation. In this context, the identification of the main managerial indicators for future command and control of existing innovation network operations under the “managing as designing” approach becomes a new challenge for future research.   Keywords: Managing as Designing; Innovation Management; Network Managament; Operations Management; Virtual Networks.

  16. HIV-related stigma in social interactions: Approach and avoidance behaviour in a virtual environment

    NARCIS (Netherlands)

    Toppenberg, H.L.; Bos, A.E.R.; Ruiter, R.A.C.; Wigboldus, D.H.J.; Pryor, J.B.

    2015-01-01

    People living with HIV are a stigmatized group in our society, especially homosexual people living with HIV. One of the behavioural manifestations of stigmatization is an increased interpersonal distance kept during social interactions. Immersive virtual environment technology enables the

  17. Novel approaches to estimating the turbulent kinetic energy dissipation rate from low- and moderate-resolution velocity fluctuation time series

    Science.gov (United States)

    Wacławczyk, Marta; Ma, Yong-Feng; Kopeć, Jacek M.; Malinowski, Szymon P.

    2017-11-01

    In this paper we propose two approaches to estimating the turbulent kinetic energy (TKE) dissipation rate, based on the zero-crossing method by Sreenivasan et al. (1983). The original formulation requires a fine resolution of the measured signal, down to the smallest dissipative scales. However, due to finite sampling frequency, as well as measurement errors, velocity time series obtained from airborne experiments are characterized by the presence of effective spectral cutoffs. In contrast to the original formulation the new approaches are suitable for use with signals originating from airborne experiments. The suitability of the new approaches is tested using measurement data obtained during the Physics of Stratocumulus Top (POST) airborne research campaign as well as synthetic turbulence data. They appear useful and complementary to existing methods. We show the number-of-crossings-based approaches respond differently to errors due to finite sampling and finite averaging than the classical power spectral method. Hence, their application for the case of short signals and small sampling frequencies is particularly interesting, as it can increase the robustness of turbulent kinetic energy dissipation rate retrieval.

  18. Novel approaches to estimating the turbulent kinetic energy dissipation rate from low- and moderate-resolution velocity fluctuation time series

    Directory of Open Access Journals (Sweden)

    M. Wacławczyk

    2017-11-01

    Full Text Available In this paper we propose two approaches to estimating the turbulent kinetic energy (TKE dissipation rate, based on the zero-crossing method by Sreenivasan et al. (1983. The original formulation requires a fine resolution of the measured signal, down to the smallest dissipative scales. However, due to finite sampling frequency, as well as measurement errors, velocity time series obtained from airborne experiments are characterized by the presence of effective spectral cutoffs. In contrast to the original formulation the new approaches are suitable for use with signals originating from airborne experiments. The suitability of the new approaches is tested using measurement data obtained during the Physics of Stratocumulus Top (POST airborne research campaign as well as synthetic turbulence data. They appear useful and complementary to existing methods. We show the number-of-crossings-based approaches respond differently to errors due to finite sampling and finite averaging than the classical power spectral method. Hence, their application for the case of short signals and small sampling frequencies is particularly interesting, as it can increase the robustness of turbulent kinetic energy dissipation rate retrieval.

  19. Towards a virtual hub approach for landscape assessment and multimedia ecomuseum using multitemporal-maps

    Directory of Open Access Journals (Sweden)

    R. Brumana

    2015-08-01

    Full Text Available Landscapes are dynamic entities, stretching and transforming across space and time, and need to be safeguarded as living places for the future, with interaction of human, social and economic dimensions. To have a comprehensive landscape evaluation several open data are needed, each one characterized by its own protocol, service interface, limiting or impeding this way interoperability and their integration. Indeed, nowadays the development of websites targeted to landscape assessment and touristic purposes requires many resources in terms of time, cost and IT skills to be implemented at different scales. For this reason these applications are limited to few cases mainly focusing on worldwide known touristic sites. The capability to spread the development of web-based multimedia virtual museum based on geospatial data relies for the future being on the possibility to discover the needed geo-spatial data through a single point of access in an homogenous way. In this paper the proposed innovative approach may facilitate the access to open data in a homogeneous way by means of specific components (the brokers performing interoperability actions required to interconnect heterogeneous data sources. In the specific case study here analysed it has been implemented an interface to migrate a geo-swat chart based on local and regional geographic information into an user friendly Google Earth©-based infrastructure, integrating ancient cadastres and modern cartography, accessible by professionals and tourists via web and also via portable devices like tables and smartphones. The general aim of this work on the case study on the Lake of Como (Tremezzina municipality, is to boost the integration of assessment methodologies with digital geo-based technologies of map correlation for the multimedia ecomuseum system accessible via web. The developed WebGIS system integrates multi-scale and multi-temporal maps with different information (cultural, historical

  20. Towards a virtual hub approach for landscape assessment and multimedia ecomuseum using multitemporal-maps

    Science.gov (United States)

    Brumana, R.; Santana Quintero, M.; Barazzetti, L.; Previtali, M.; Banfi, F.; Oreni, D.; Roels, D.; Roncoroni, F.

    2015-08-01

    Landscapes are dynamic entities, stretching and transforming across space and time, and need to be safeguarded as living places for the future, with interaction of human, social and economic dimensions. To have a comprehensive landscape evaluation several open data are needed, each one characterized by its own protocol, service interface, limiting or impeding this way interoperability and their integration. Indeed, nowadays the development of websites targeted to landscape assessment and touristic purposes requires many resources in terms of time, cost and IT skills to be implemented at different scales. For this reason these applications are limited to few cases mainly focusing on worldwide known touristic sites. The capability to spread the development of web-based multimedia virtual museum based on geospatial data relies for the future being on the possibility to discover the needed geo-spatial data through a single point of access in an homogenous way. In this paper the proposed innovative approach may facilitate the access to open data in a homogeneous way by means of specific components (the brokers) performing interoperability actions required to interconnect heterogeneous data sources. In the specific case study here analysed it has been implemented an interface to migrate a geo-swat chart based on local and regional geographic information into an user friendly Google Earth©-based infrastructure, integrating ancient cadastres and modern cartography, accessible by professionals and tourists via web and also via portable devices like tables and smartphones. The general aim of this work on the case study on the Lake of Como (Tremezzina municipality), is to boost the integration of assessment methodologies with digital geo-based technologies of map correlation for the multimedia ecomuseum system accessible via web. The developed WebGIS system integrates multi-scale and multi-temporal maps with different information (cultural, historical, landscape levels

  1. After Virtual Archaeology: Rethinking Archaeological Approaches to the Adoption of Digital Technology

    Directory of Open Access Journals (Sweden)

    Gareth Beale

    2017-06-01

    Full Text Available In the 1980s archaeologists embraced the rapidly expanding field of computer modelling and visualisation as a vehicle for data exploration. Against this backdrop 'virtual archaeology' was conceived. The term was originally intended to describe a multidimensional approach to the modelling of the (immaterial structures and processes of field archaeology. It described how technology could be harnessed in order to achieve new ways of documenting, interpreting and annotating primary archaeological discoveries and processes. Despite their initial promise, these digital technologies failed to have the impact upon archaeological fieldwork that might have been expected. Even with the prevalence of digital devices on all archaeological excavations, the documentation, interpretation and subsequent narration of archaeological processes have retained their analogue character. While the archaeological record is now primarily digital, its sections, plans, drawings and photographs are facsimiles of the analogue technologies that preceded them. This retention of analogue conventions is increasingly out of step with the general prevalence and diversity of digital technologies as mediators of professional and private life. It is also challenged by 21st-century advances towards technologies that allow for complex engagements with and representations of physical matter and facilitate the interplay between digital and material worlds. This article argues that emerging forms of archaeological practice including gaming, mixed reality, computational photography and additive manufacturing, reveal digital archaeology to be a creative process, blending computational thinking, technological opportunities and established disciplinary traditions. We go on to suggest that digital archaeology, conceived as a form of practice rather than as a toolset, represents a locus for theory generation and critical thinking. Failure to recognise the skills and ideas that have emerged in

  2. Using a clinical protocol for orthognathic surgery and assessing a 3-dimensional virtual approach: current therapy.

    Science.gov (United States)

    Quevedo, Luis A; Ruiz, Jessica V; Quevedo, Cristobal A

    2011-03-01

    Oral and maxillofacial surgeons who perform orthognathic surgery face major changes in their practices, and these challenges will increase in the near future, because the extraordinary advances in technology applied to our profession are not only amazing but are becoming the standard of care as they promote improved outcomes for our patients. Orthognathic surgery is one of the favorite areas of practicing within the scope of practice of an oral and maxillofacial surgeon. Our own practice in orthognathic surgery has completed over 1,000 surgeries of this type. Success is directly related to the consistency and capability of the surgical-orthodontic team to achieve predictable, stable results, and our hypothesis is that a successful result is directly related to the way we take our records and perform diagnosis and treatment planning following basic general principles. Now that we have the opportunity to plan and treat 3-dimensional (3D) problems with 3D technology, we should enter into this new era with appropriate standards to ensure better results, instead of simply enjoying these new tools, which will clearly show not only us but everyone what we do when we perform orthognathic surgery. Appropriate principles need to be taken into account when implementing this new technology. In other words, new technology is welcome, but we do not have to reinvent the wheel. The purpose of this article is to review the current protocol that we use for orthognathic surgery and compare it with published protocols that incorporate new 3D and virtual technology. This report also describes our approach to this new technology. Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  3. Dynamical properties for the problem of a particle in an electric field of wave packet: Low velocity and relativistic approach

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Diego F.M., E-mail: diegofregolente@gmail.com [Institute for Multiscale Simulations, Friedrich-Alexander Universität, D-91052, Erlangen (Germany); Leonel, Edson D., E-mail: edleonel@rc.unesp.br [Departamento de Estatística, Matemática Aplicada e Computação, UNESP, Univ. Estadual Paulista, Av. 24A, 1515, Bela Vista, 13506-900, Rio Claro, SP (Brazil); Departamento de Física, UNESP, Univ. Estadual Paulista, Av. 24A, 1515, 13506-900, Rio Claro, SP (Brazil)

    2012-11-01

    We study some dynamical properties for the problem of a charged particle in an electric field considering both the low velocity and relativistic cases. The dynamics for both approaches is described in terms of a two-dimensional and nonlinear mapping. The structure of the phase spaces is mixed and we introduce a hole in the chaotic sea to let the particles to escape. By changing the size of the hole we show that the survival probability decays exponentially for both cases. Additionally, we show for the relativistic dynamics, that the introduction of dissipation changes the mixed phase space and attractors appear. We study the parameter space by using the Lyapunov exponent and the average energy over the orbit and show that the system has a very rich structure with infinite family of self-similar shrimp shaped embedded in a chaotic region.

  4. Exploring the use of Virtual Field Trips with elementary school teachers: A collaborative action research approach

    Science.gov (United States)

    Scott, Jeffrey Lance

    This research examines how elementary school teachers, when supported, use Virtual Field Trips (VFTs) to address the curricula in meaningful ways. I conducted a qualitative study with six teachers, in a collaborative action research context over a six month period. The teachers, five males and one female, all taught either grade five or six and utilized Virtual Field Trips within a variety of curricula areas including science, social studies, music and language arts. In addition, the thesis examines resulting integration of technology into the regular classroom program as a product of the utilization of Virtual Field Trips. The process of collaborative action research was applied as a means of personal and professional growth both for the participants and the researcher/facilitator. By the end of the research study, all participants had learned to integrate Virtual Field Trips into their classroom program, albeit with different levels of success and in different curricula areas. The development of attitudes, skills and knowledge for students and teachers alike was fostered through the participation in Virtual Field Trips. A common concern regarding the utilization of Virtual Field Trips was the time spent locating an appropriate site that met curricula expectations. Participation in the collaborative action research process allowed each teacher to grow professionally, personally and socially. Each participant strongly encouraged the utilization of a long term project with a common area of exploration as a means for positive professional development. Implications and recommendations for future research on the utilization of Virtual Field Trips, as well as the viability of collaborative action research to facilitate teacher development are presented.

  5. Innovation in weight loss programs: a 3-dimensional virtual-world approach.

    Science.gov (United States)

    Johnston, Jeanne D; Massey, Anne P; Devaneaux, Celeste A

    2012-09-20

    The rising trend in obesity calls for innovative weight loss programs. While behavioral-based face-to-face programs have proven to be the most effective, they are expensive and often inaccessible. Internet or Web-based weight loss programs have expanded reach but may lack qualities critical to weight loss and maintenance such as human interaction, social support, and engagement. In contrast to Web technologies, virtual reality technologies offer unique affordances as a behavioral intervention by directly supporting engagement and active learning. To explore the effectiveness of a virtual-world weight loss program relative to weight loss and behavior change. We collected data from overweight people (N = 54) participating in a face-to-face or a virtual-world weight loss program. Weight, body mass index (BMI), percentage weight change, and health behaviors (ie, weight loss self-efficacy, physical activity self-efficacy, self-reported physical activity, and fruit and vegetable consumption) were assessed before and after the 12-week program. Repeated measures analysis was used to detect differences between groups and across time. A total of 54 participants with a BMI of 32 (SD 6.05) kg/m(2)enrolled in the study, with a 13% dropout rate for each group (virtual world group: 5/38; face-to-face group: 3/24). Both groups lost a significant amount of weight (virtual world: 3.9 kg, P virtual-world group lost an average of 4.2%, with 33% (11/33) of the participants losing a clinically significant (≥5%) amount of baseline weight. The face-to-face group lost an average of 3.0% of their baseline weight, with 29% (6/21) losing a clinically significant amount. We detected a significant group × time interaction for moderate (P = .006) and vigorous physical activity (P = .008), physical activity self-efficacy (P = .04), fruit and vegetable consumption (P = .007), and weight loss self-efficacy (P virtual-world group. Overall, these results offer positive early evidence that a

  6. Ground Motion Prediction for M7+ scenarios on the San Andreas Fault using the Virtual Earthquake Approach

    Science.gov (United States)

    Denolle, M.; Dunham, E. M.; Prieto, G.; Beroza, G. C.

    2013-05-01

    There is no clearer example of the increase in hazard due to prolonged and amplified shaking in sedimentary, than the case of Mexico City in the 1985 Michoacan earthquake. It is critically important to identify what other cities might be susceptible to similar basin amplification effects. Physics-based simulations in 3D crustal structure can be used to model and anticipate those effects, but they rely on our knowledge of the complexity of the medium. We propose a parallel approach to validate ground motion simulations using the ambient seismic field. We compute the Earth's impulse response combining the ambient seismic field and coda-wave enforcing causality and symmetry constraints. We correct the surface impulse responses to account for the source depth, mechanism and duration using a 1D approximation of the local surface-wave excitation. We call the new responses virtual earthquakes. We validate the ground motion predicted from the virtual earthquakes against moderate earthquakes in southern California. We then combine temporary seismic stations on the southern San Andreas Fault and extend the point source approximation of the Virtual Earthquake Approach to model finite kinematic ruptures. We confirm the coupling between source directivity and amplification in downtown Los Angeles seen in simulations.

  7. Hybrid Motion Planning Method for Autonomous Robots Using Kinect Based Sensor Fusion and Virtual Plane Approach in Dynamic Environments

    Directory of Open Access Journals (Sweden)

    Doopalam Tuvshinjargal

    2015-01-01

    Full Text Available A new reactive motion planning method for an autonomous vehicle in dynamic environments is proposed. The new dynamic motion planning method combines a virtual plane based reactive motion planning technique with a sensor fusion based obstacle detection approach, which results in improving robustness and autonomy of vehicle navigation within unpredictable dynamic environments. The key feature of the new reactive motion planning method is based on a local observer in the virtual plane which allows the effective transformation of complex dynamic planning problems into simple stationary in the virtual plane. In addition, a sensor fusion based obstacle detection technique provides the pose estimation of moving obstacles by using a Kinect sensor and a sonar sensor, which helps to improve the accuracy and robustness of the reactive motion planning approach in uncertain dynamic environments. The performance of the proposed method was demonstrated through not only simulation studies but also field experiments using multiple moving obstacles even in hostile environments where conventional method failed.

  8. Virtual Screening Approaches towards the Discovery of Toll-Like Receptor Modulators

    Directory of Open Access Journals (Sweden)

    Lucía Pérez-Regidor

    2016-09-01

    Full Text Available This review aims to summarize the latest efforts performed in the search for novel chemical entities such as Toll-like receptor (TLR modulators by means of virtual screening techniques. This is an emergent research field with only very recent (and successful contributions. Identification of drug-like molecules with potential therapeutic applications for the treatment of a variety of TLR-regulated diseases has attracted considerable interest due to the clinical potential. Additionally, the virtual screening databases and computational tools employed have been overviewed in a descriptive way, widening the scope for researchers interested in the field.

  9. Influence of the contact roughness upon railway monobloc wheel acoustic behaviour on virtual prototyping approach

    Science.gov (United States)

    Todorov, George; Kamberov, Konstantin; Kralov, Ivan; Ignatov, Ignat

    2017-12-01

    In this study the virtual prototyping is used for evaluation the influence of the contact roughness upon the acoustic behaviour evaluation of railway monobloc wheel. The proposed procedure covers requirements of the European Standard EN 13979-1 "Wheels and bogies - Monobloc wheels". The main advantage of the acoustic assessment based on the virtual engineering technics - absence of the expensive and time consuming physical tests, is sown. The real industrial-project example is presented and comparison of the numerical and experimental results is used for acoustic behaviour assessment and approval of railway monobloc wheel design.

  10. Image Mosaicking Approach for a Double-Camera System in the GaoFen2 Optical Remote Sensing Satellite Based on the Big Virtual Camera.

    Science.gov (United States)

    Cheng, Yufeng; Jin, Shuying; Wang, Mi; Zhu, Ying; Dong, Zhipeng

    2017-06-20

    The linear array push broom imaging mode is widely used for high resolution optical satellites (HROS). Using double-cameras attached by a high-rigidity support along with push broom imaging is one method to enlarge the field of view while ensuring high resolution. High accuracy image mosaicking is the key factor of the geometrical quality of complete stitched satellite imagery. This paper proposes a high accuracy image mosaicking approach based on the big virtual camera (BVC) in the double-camera system on the GaoFen2 optical remote sensing satellite (GF2). A big virtual camera can be built according to the rigorous imaging model of a single camera; then, each single image strip obtained by each TDI-CCD detector can be re-projected to the virtual detector of the big virtual camera coordinate system using forward-projection and backward-projection to obtain the corresponding single virtual image. After an on-orbit calibration and relative orientation, the complete final virtual image can be obtained by stitching the single virtual images together based on their coordinate information on the big virtual detector image plane. The paper subtly uses the concept of the big virtual camera to obtain a stitched image and the corresponding high accuracy rational function model (RFM) for concurrent post processing. Experiments verified that the proposed method can achieve seamless mosaicking while maintaining the geometric accuracy.

  11. Simulating Nature for Elderly Users - A Design Approach for Recreational Virtual Environments

    DEFF Research Database (Denmark)

    Bruun-Pedersen, Jon Ram; Serafin, Stefania; Kofoed, Lise

    2015-01-01

    Recreational nature experiences are rehabilitative for humans. Nature-oriented virtual environments (VEs) might be able to provide similar experiences. A pilot study have shown to increase the enjoyment of an exercise experience for retirement home residents, by augmenting their everyday bike...

  12. Investigating Learners' Attitudes toward Virtual Reality Learning Environments: Based on a Constructivist Approach

    Science.gov (United States)

    Huang, Hsiu-Mei; Rauch, Ulrich; Liaw, Shu-Sheng

    2010-01-01

    The use of animation and multimedia for learning is now further extended by the provision of entire Virtual Reality Learning Environments (VRLE). This highlights a shift in Web-based learning from a conventional multimedia to a more immersive, interactive, intuitive and exciting VR learning environment. VRLEs simulate the real world through the…

  13. An Activity Theory Approach to Analyze Barriers to a Virtual Management Information Systems (MIS) Curriculum

    Science.gov (United States)

    Jaradat, Suhair; Qablan, Ahmad; Barham, Areej

    2011-01-01

    This paper explains how the activity theory is used as a framework to analyze the barriers to a virtual Management Information Stream (MIS) Curriculum in Jordanian schools, from both the sociocultural and pedagogical perspectives. Taking the activity system as a unit of analysis, this study documents the processes by which activities shape and are…

  14. Application of Semantic Approaches and Interactive Virtual Technology to Improve Teaching Effectiveness

    Science.gov (United States)

    Jou, Min; Liu, Chi-Chia

    2012-01-01

    This article describes an implementation of interactive virtual environments that have been designed for supporting the education of technical skills in material processing technology. The developed web-based systems provide the capability to train students in the technical skills of material processing technology without the need to work on…

  15. A virtual structure approach to formation control of unicycle mobile robots using mutual coupling

    NARCIS (Netherlands)

    Sadowska, A.; Broek, T.H.A. van den; Huijberts, H.; Wouw, N. van de; Kostić, D.; Nijmeijer, H.

    2011-01-01

    In this article, the formation control problem for unicycle mobile robots is studied. A distributed virtual structure control strategy with mutual coupling between the robots is proposed. The rationale behind the introduction of the coupling terms is the fact that these introduce additional

  16. Virtual Boutique: a 3D modeling and content-based management approach to e-commerce

    Science.gov (United States)

    Paquet, Eric; El-Hakim, Sabry F.

    2000-12-01

    The Virtual Boutique is made out of three modules: the decor, the market and the search engine. The decor is the physical space occupied by the Virtual Boutique. It can reproduce any existing boutique. For this purpose, photogrammetry is used. A set of pictures of a real boutique or space is taken and a virtual 3D representation of this space is calculated from them. Calculations are performed with software developed at NRC. This representation consists of meshes and texture maps. The camera used in the acquisition process determines the resolution of the texture maps. Decorative elements are added like painting, computer generated objects and scanned objects. The objects are scanned with laser scanner developed at NRC. This scanner allows simultaneous acquisition of range and color information based on white laser beam triangulation. The second module, the market, is made out of all the merchandises and the manipulators, which are used to manipulate and compare the objects. The third module, the search engine, can search the inventory based on an object shown by the customer in order to retrieve similar objects base don shape and color. The items of interest are displayed in the boutique by reconfiguring the market space, which mean that the boutique can be continuously customized according to the customer's needs. The Virtual Boutique is entirely written in Java 3D and can run in mono and stereo mode and has been optimized in order to allow high quality rendering.

  17. Optimization of enrichment for virtual ligand screening using an established FRED-Surflex approach

    NARCIS (Netherlands)

    Du, J.; Bleylevens, I.W.M.; Bitorina, Albert; Nicolaes, G.A.F.

    2012-01-01

    Virtual ligand screening (VLS) is an in silico technology used for the productive and cost effective search for novel hit or lead compounds. VLS can be divided into rigid body docking (e.g. FRED) and flexible body docking (e.g. Surflex) procedures. Theoretically, rigid body docking VLS is fast but

  18. A Cross-Entropy-Based Admission Control Optimization Approach for Heterogeneous Virtual Machine Placement in Public Clouds

    Directory of Open Access Journals (Sweden)

    Li Pan

    2016-03-01

    Full Text Available Virtualization technologies make it possible for cloud providers to consolidate multiple IaaS provisions into a single server in the form of virtual machines (VMs. Additionally, in order to fulfill the divergent service requirements from multiple users, a cloud provider needs to offer several types of VM instances, which are associated with varying configurations and performance, as well as different prices. In such a heterogeneous virtual machine placement process, one significant problem faced by a cloud provider is how to optimally accept and place multiple VM service requests into its cloud data centers to achieve revenue maximization. To address this issue, in this paper, we first formulate such a revenue maximization problem during VM admission control as a multiple-dimensional knapsack problem, which is known to be NP-hard to solve. Then, we propose to use a cross-entropy-based optimization approach to address this revenue maximization problem, by obtaining a near-optimal eligible set for the provider to accept into its data centers, from the waiting VM service requests in the system. Finally, through extensive experiments and measurements in a simulated environment with the settings of VM instance classes derived from real-world cloud systems, we show that our proposed cross-entropy-based admission control optimization algorithm is efficient and effective in maximizing cloud providers’ revenue in a public cloud computing environment.

  19. Inverted L osteotomy: a new approach via intraoral access through the advances of virtual surgical planning and custom fixation

    Directory of Open Access Journals (Sweden)

    Peter B. Franco, DMD

    2016-03-01

    Full Text Available We introduce a novel surgical approach via intraoral access to the Inverted L osteotomy utilizing virtual surgical planning (VSP and patient-specific customized mandibular fixation. VSP in orthognathic surgery has been well documented in its ability to increase preoperative and intraoperative efficiency, decrease cost and operating room time, and improve predictability and patient outcomes. In addition to occlusal splints, the adjunctive cutting guides and reference templates generated through computer-aided design and computer-aided manufacturing further aids in the precise transfer of the virtual plan to the intraoperative procedure. As the application of VSP is becoming more prevalent in the surgical treatment dentofacial deformities, 3-D virtual planning is moving beyond cutting jigs and guides and into the fabrication of patient-specific customized mandibular reconstruction plates in both the orthognathic and reconstructive arenas. Orthognathic surgery can be essential for the establishment of sound function and ideal esthetics for individuals who possess a dentofacial deformity. VSP and customized mandibular reconstruction plates have great potential to help safely guide the inverted L osteotomy and produce predictable functional and esthetic results while improving efficiency preoperatively as well as intraoperatively.

  20. A Transverse Oscillation Approach for Estimation of Three-Dimensional Velocity Vectors, Part I: Concept and Simulation Study

    DEFF Research Database (Denmark)

    Pihl, Michael Johannes; Jensen, Jørgen Arendt

    2014-01-01

    A method for 3-D velocity vector estimation us - ing transverse oscillations is presented. The method employs a 2-D transducer and decouples the velocity estimation into three orthogonal components, which are estimated simultane - ously and from the same data. The validity of the method is invest......A method for 3-D velocity vector estimation us - ing transverse oscillations is presented. The method employs a 2-D transducer and decouples the velocity estimation into three orthogonal components, which are estimated simultane - ously and from the same data. The validity of the method...

  1. Sensitivity analysis of an LCL-filter-based three-phase active rectifier via a virtual circuit approach

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Chiarantoni, Ernesto; Aquila, Antonio Dell’

    2004-01-01

    , to the grid side stiffness and to the parameters of the controller has never been detailed considered. In this paper the experimental results of an LCL-filter-based three-phase active rectifier are analysed with the circuit theory approach. A ?virtual circuit? is synthesized in role of the digital controller......Three-phase active rectifiers based on the voltage source converter topology can successfully replace traditional thyristor based rectifiers or diode bridge plus chopper in interfacing dc-systems to the grid. However, if the application in which they are employed has a high safety issue...

  2. Smart communities in virtual reality. A comparison of design approaches for academic education

    Directory of Open Access Journals (Sweden)

    Thomas Köhler

    2014-11-01

    Full Text Available Smart communities adopt „virtual reality” (VR for many purposes, amongst others for educational purposes. However the development of educational technologies under the concept of „„VR is neither a core issue in academic education nor in applied research publications, although potential exists. With the goal of closing this gap, the authors investigate possibilities of VR in teaching and training. Whether we can speak of a new didactic technique and if certain smart communities adopt such is investigated through three cases. Our focus is on who the target audience is, what requirements need to be considered, and how this manifests in the teachers’ activity. Subsequently, a starting point for a target group-oriented design of virtual reality in higher education is provided.

  3. Virtual Vision

    Science.gov (United States)

    Terzopoulos, Demetri; Qureshi, Faisal Z.

    Computer vision and sensor networks researchers are increasingly motivated to investigate complex multi-camera sensing and control issues that arise in the automatic visual surveillance of extensive, highly populated public spaces such as airports and train stations. However, they often encounter serious impediments to deploying and experimenting with large-scale physical camera networks in such real-world environments. We propose an alternative approach called "Virtual Vision", which facilitates this type of research through the virtual reality simulation of populated urban spaces, camera sensor networks, and computer vision on commodity computers. We demonstrate the usefulness of our approach by developing two highly automated surveillance systems comprising passive and active pan/tilt/zoom cameras that are deployed in a virtual train station environment populated by autonomous, lifelike virtual pedestrians. The easily reconfigurable virtual cameras distributed in this environment generate synthetic video feeds that emulate those acquired by real surveillance cameras monitoring public spaces. The novel multi-camera control strategies that we describe enable the cameras to collaborate in persistently observing pedestrians of interest and in acquiring close-up videos of pedestrians in designated areas.

  4. A Multi-Layer Approach of Interactive Path Planning for Assisted Manipulation in Virtual Reality

    OpenAIRE

    Cailhol, Simon; Fillatreau, Philippe; Fourquet, Jean-Yves; Zhao, Yingshen

    2015-01-01

    International audience; This work considers Virtual Reality (VR) applications dealing with objects manipulation (such as industrial product assembly, disassembly or maintenance simulation). For such applications, the operator performing the simulation can be assisted by path planning techniques from the robotics research field. A novel automatic path planner involving geometrical, topological and semantic information of the environment is proposed for the guidance of the user through a haptic...

  5. A class Hierarchical, object-oriented approach to virtual memory management

    Science.gov (United States)

    Russo, Vincent F.; Campbell, Roy H.; Johnston, Gary M.

    1989-01-01

    The Choices family of operating systems exploits class hierarchies and object-oriented programming to facilitate the construction of customized operating systems for shared memory and networked multiprocessors. The software is being used in the Tapestry laboratory to study the performance of algorithms, mechanisms, and policies for parallel systems. Described here are the architectural design and class hierarchy of the Choices virtual memory management system. The software and hardware mechanisms and policies of a virtual memory system implement a memory hierarchy that exploits the trade-off between response times and storage capacities. In Choices, the notion of a memory hierarchy is captured by abstract classes. Concrete subclasses of those abstractions implement a virtual address space, segmentation, paging, physical memory management, secondary storage, and remote (that is, networked) storage. Captured in the notion of a memory hierarchy are classes that represent memory objects. These classes provide a storage mechanism that contains encapsulated data and have methods to read or write the memory object. Each of these classes provides specializations to represent the memory hierarchy.

  6. Virtual modeling

    NARCIS (Netherlands)

    Flores, J.; Kiss, S.; Cano, P.; Nijholt, Antinus; Zwiers, Jakob

    2003-01-01

    We concentrate our efforts on building virtual modelling environments where the content creator uses controls (widgets) as an interactive adjustment modality for the properties of the edited objects. Besides the advantage of being an on-line modelling approach (visualised just like any other on-line

  7. Network Virtualization Protocols

    OpenAIRE

    Fornazarič, Nejc

    2014-01-01

    Server virtualization is a widespread and well known technology that has fundamentally changed the operations in data centers. Virtual servers and data storage can be fast and easily provisioned. On the other hand network requires a lot of administrative changes and configurations that increase time of adoption. The consequences of server virtualization are changed requirements for network resources therefore the next logical step is network virtualization. The different approaches for netwo...

  8. Estimation of vector velocity

    DEFF Research Database (Denmark)

    2000-01-01

    Using a pulsed ultrasound field, the two-dimensional velocity vector can be determined with the invention. The method uses a transversally modulated ultrasound field for probing the moving medium under investigation. A modified autocorrelation approach is used in the velocity estimation. The new...... estimator automatically compensates for the axial velocity, when determining the transverse velocity by using fourth order moments rather than second order moments. The estimation is optimized by using a lag different from one in the estimation process, and noise artifacts are reduced by using averaging...... of RF samples. Further, compensation for the axial velocity can be introduced, and the velocity estimation is done at a fixed depth in tissue to reduce spatial velocity dispersion....

  9. Escape Velocity

    Directory of Open Access Journals (Sweden)

    Nikola Vlacic

    2010-01-01

    Full Text Available In this project, we investigated if it is feasible for a single staged rocket with constant thrust to attain escape velocity. We derived an equation for the velocity and position of a single staged rocket that launches vertically. From this equation, we determined if an ideal model of a rocket is able to reach escape velocity.

  10. Computing continuous record of discharge with quantified uncertainty using index velocity observations: A probabilistic machine learning approach

    Science.gov (United States)

    Farahmand, Touraj; Hamilton, Stuart

    2016-04-01

    Application of the index velocity method for computing continuous records of discharge has become increasingly common, especially since the introduction of low-cost acoustic Doppler velocity meters (ADVMs). In general, the index velocity method can be used at locations where stage-discharge methods are used, but it is especially appropriate and recommended when more than one specific discharge can be measured for a specific stage such as backwater and unsteady flow conditions caused by but not limited to the following; stream confluences, streams flowing into lakes or reservoirs, tide-affected streams, regulated streamflows (dams or control structures), or streams affected by meteorological forcing, such as strong prevailing winds. In existing index velocity modeling techniques, two models (ratings) are required; index velocity model and stage-area model. The outputs from each of these models, mean channel velocity (Vm) and cross-sectional area (A), are then multiplied together to compute a discharge. Mean channel velocity (Vm) can generally be determined by a multivariate regression parametric model such as linear regression in the simplest case. The main challenges in the existing index velocity modeling techniques are; 1) Preprocessing and QA/QC of continuous index velocity data and synchronizing them with discharge measurements. 2) Nonlinear relationship between mean velocity and index velocity which is not uncommon at monitoring locations. 3)Model exploration and analysis in order to find the optimal regression model predictor(s) and model type (linear vs nonlinear and if nonlinear number of the parameters). 3) Model changes caused by dynamical changes in the environment (geomorphic, biological) over time 5) Deployment of the final model into the Data Management Systems (DMS) for real-time discharge calculation 6) Objective estimation of uncertainty caused by: field measurement errors; structural uncertainty; parameter uncertainty; and continuous sensor data

  11. Virtual landmarks

    Science.gov (United States)

    Tong, Yubing; Udupa, Jayaram K.; Odhner, Dewey; Bai, Peirui; Torigian, Drew A.

    2017-03-01

    Much has been published on finding landmarks on object surfaces in the context of shape modeling. While this is still an open problem, many of the challenges of past approaches can be overcome by removing the restriction that landmarks must be on the object surface. The virtual landmarks we propose may reside inside, on the boundary of, or outside the object and are tethered to the object. Our solution is straightforward, simple, and recursive in nature, proceeding from global features initially to local features in later levels to detect landmarks. Principal component analysis (PCA) is used as an engine to recursively subdivide the object region. The object itself may be represented in binary or fuzzy form or with gray values. The method is illustrated in 3D space (although it generalizes readily to spaces of any dimensionality) on four objects (liver, trachea and bronchi, and outer boundaries of left and right lungs along pleura) derived from 5 patient computed tomography (CT) image data sets of the thorax and abdomen. The virtual landmark identification approach seems to work well on different structures in different subjects and seems to detect landmarks that are homologously located in different samples of the same object. The approach guarantees that virtual landmarks are invariant to translation, scaling, and rotation of the object/image. Landmarking techniques are fundamental for many computer vision and image processing applications, and we are currently exploring the use virtual landmarks in automatic anatomy recognition and object analytics.

  12. Innovative approaches to the rehabilitation of upper extremity hemiparesis using virtual environments

    Science.gov (United States)

    MERIANS, A. S.; TUNIK, E.; FLUET, G. G.; QIU, Q.; ADAMOVICH, S. V.

    2017-01-01

    Aim Upper-extremity interventions for hemiparesis are a challenging aspect of stroke rehabilitation. Purpose of this paper is to report the feasibility of using virtual environments (VEs) in combination with robotics to assist recovery of hand-arm function and to present preliminary data demonstrating the potential of using sensory manipulations in VE to drive activation in targeted neural regions. Methods We trained 8 subjects for 8 three hour sessions using a library of complex VE’s integrated with robots, comparing training arm and hand separately to training arm and hand together. Instrumented gloves and hand exoskeleton were used for hand tracking and haptic effects. Haptic Master robotic arm was used for arm tracking and generating three-dimensional haptic VEs. To investigate the use of manipulations in VE to drive neural activations, we created a “virtual mirror” that subjects used while performing a unimanual task. Cortical activation was measured with functional MRI (fMRI) and transcranial magnetic stimulation. Results Both groups showed improvement in kinematics and measures of real-world function. The group trained using their arm and hand together showed greater improvement. In a stroke subject, fMRI data suggested virtual mirror feedback could activate the sensorimotor cortex contralateral to the reflected hand (ipsilateral to the moving hand) thus recruiting the lesioned hemisphere. Conclusion Gaming simulations interfaced with robotic devices provide a training medium that can modify movement patterns. In addition to showing that our VE therapies can optimize behavioral performance, we show preliminary evidence to support the potential of using specific sensory manipulations to selectively recruit targeted neural circuits. PMID:19158659

  13. Virtual and Physical Recomposition of Fragmented Ecclesiastical Frescoes Using a Photogrammetric Approach

    Science.gov (United States)

    Abate, D.; Hermon, S.; Eliades, I.

    2016-06-01

    The octagonal domed church of the Christ Antiphonitis in the district of Kyrenia (Cyprus) was originally completely decorated with frescoes along its interior walls. Two of these are exceptional for their artistic and historic value: the story of the Tree of Jesse (a pictorial genealogy of the Virgin) located on the southern wall of the octagon, and the Last Judgment, on the northern wall. Following the invasion of Cyprus by Turkish military forces in 1974, looters stripped many of the region churches, removing an estimated 15,000 to 20,000 icons and several dozen major frescoes and mosaics, intending to sell them illegally on the antique market. The Church of Antiphonitis was among them. The walls with the two biblical episodes suffered major damages and big portions of their pictorial decoration were removed. Since the end of the 1990s, due to efforts of Cypriot authorities, more than 70 fragments of its frescoes returned from USA and Europe to the Byzantine Museum of Nicosia, where they are currently under conservation and restoration for future display. These were digitally documented through high-resolution ortophotos. The inner space of the church was documented by similar means, in order to virtually re-position the frescoes in their original locations. The virtual re-composition of the frescoes along the looted walls helped quantifying the missing parts, correctly re-locate virtually each fragment at its original position, obtain accurate colour information and prepare a digital musealisation product, to be included in the permanent exhibition display at the museum which will feature a 1:1 scale reproduction of the church walls.

  14. VIRTUAL AND PHYSICAL RECOMPOSITION OF FRAGMENTED ECCLESIASTICAL FRESCOES USING A PHOTOGRAMMETRIC APPROACH

    Directory of Open Access Journals (Sweden)

    D. Abate

    2016-06-01

    Full Text Available The octagonal domed church of the Christ Antiphonitis in the district of Kyrenia (Cyprus was originally completely decorated with frescoes along its interior walls. Two of these are exceptional for their artistic and historic value: the story of the Tree of Jesse (a pictorial genealogy of the Virgin located on the southern wall of the octagon, and the Last Judgment, on the northern wall. Following the invasion of Cyprus by Turkish military forces in 1974, looters stripped many of the region churches, removing an estimated 15,000 to 20,000 icons and several dozen major frescoes and mosaics, intending to sell them illegally on the antique market. The Church of Antiphonitis was among them. The walls with the two biblical episodes suffered major damages and big portions of their pictorial decoration were removed. Since the end of the 1990s, due to efforts of Cypriot authorities, more than 70 fragments of its frescoes returned from USA and Europe to the Byzantine Museum of Nicosia, where they are currently under conservation and restoration for future display. These were digitally documented through high-resolution ortophotos. The inner space of the church was documented by similar means, in order to virtually re-position the frescoes in their original locations. The virtual re-composition of the frescoes along the looted walls helped quantifying the missing parts, correctly re-locate virtually each fragment at its original position, obtain accurate colour information and prepare a digital musealisation product, to be included in the permanent exhibition display at the museum which will feature a 1:1 scale reproduction of the church walls.

  15. Virtual Touch

    DEFF Research Database (Denmark)

    Stenslie, Ståle

    Erotogod. The third chapter investigates the foundations of touch through a physiological and psychological approach. Chapter four presents an alternative haptic history of Virtual Realities through the presentation and discussion of several technological and artistic works that are computer...... is the analysis and conclusion of my experiments. The problems addressed concern how it feels to touch and be touched in multimodal environments, or so called Virtual Realities. Firstly how haptic, corporeal interaction influence the overall experience of a given interactive human-to-computer system. Secondly...... and the psychophysically-contextualized work of art The main results and applications of the study are firstly that haptic technologies bridge the gap between the real (corporeal) and the virtual (immaterial) world, supporting the assumption that the distinction between the ‘virtual’ and the ‘real’ is not convincing...

  16. [Real time virtual sonography: a new approach in the evaluation of fetal cerebral structures?].

    Science.gov (United States)

    Brasseur-Daudruy, M; Diguet, A; Dacher, J-N; Verspyck, E

    2014-05-01

    If ultrasonography is the first intention exam in the evaluation of fetal cerebral structures, MR is the second intention exam the indications of which are well defined. Both techniques are complementary but still independent and the retrospective synthesis of these exams allows optimal analysis of fetal cerebral anomalies. Real time virtual sonography can synchronize a sonographic image and MRI multiplanar image of the same section in real time. This technique can be performed in the evaluation of fetal cerebral structures and synchronous recognition of anatomic structures and has many advantages especially on the pedagogic plan. However, this technique is currently limited to the research area. Copyright © 2014. Published by Elsevier SAS.

  17. A Bidding Model for a Virtual Power Plant via Robust Optimization Approach

    Directory of Open Access Journals (Sweden)

    Geng Tianxiang

    2017-01-01

    Full Text Available The evolution of the energy markets has been accelerating the use of distributed energy resources (DERs all over the world. Virtual power plant (VPP is a new method to management this increasing two-way complexity. In this paper, a bidding model for a VPP via robust optimization in the uncertain environment of the electricity market is presented. The flexible feature embedded in the model with respect to solution accuracy and computation burden would be advantageous to the VPP. Results of a case study are provided to show the applicability of the proposed bidding model.

  18. Sound Design in Virtual Reality Concert Experiences using a Wave Field Synthesis Approach

    DEFF Research Database (Denmark)

    Lind, Rasmus Bloustrød; Milesen, Victor; Smed, Dina Madsen

    2017-01-01

    In this paper we propose an experiment that evaluates the influence of audience noise on the feeling of presence and the perceived quality in a virtual reality concert experience delivered using Wave Field Synthesis. A 360 degree video of a live rock concert from a local band was recorded. Single...... sound sources from the stage and the PA system were recorded, as well as the audience noise, and impulse responses of the concert venue. The audience noise was implemented in the production phase. A comparative study compared an experience with and without audience noise. In a between subject experiment...

  19. Teaching Information Systems Technologies: a New Approach based on Virtualization and Hosting Technologies

    Directory of Open Access Journals (Sweden)

    Carmelo R. García

    2012-11-01

    Full Text Available This paper describes how to provide suitable computing systems for information systems technologies learning using virtualization and hosting technologies. The main functionalities and components of an university learning lab based on these technologies are presented. All the software components used in its development are open source. Also, the use of this lab, providing the computing systems required for the learning activities of different matters related to the information systems technologies, is illustrated. The model of computing lab proposed is a more sustainable and scalable alternative than the traditional academic computing lab.

  20. A Data-Driven Control Design Approach for Freeway Traffic Ramp Metering with Virtual Reference Feedback Tuning

    Directory of Open Access Journals (Sweden)

    Shangtai Jin

    2014-01-01

    Full Text Available ALINEA is a simple, efficient, and easily implemented ramp metering strategy. Virtual reference feedback tuning (VRFT is most suitable for many practical systems since it is a “one-shot” data-driven control design methodology. This paper presents an application of VRFT to a ramp metering problem of freeway traffic system. When there is not enough prior knowledge of the controlled system to select a proper parameter of ALINEA, the VRFT approach is used to optimize the ALINEA's parameter by only using a batch of input and output data collected from the freeway traffic system. The extensive simulations are built on both the macroscopic MATLAB platform and the microscopic PARAMICS platform to show the effectiveness and applicability of the proposed data-driven controller tuning approach.

  1. Acoustic Doppler current profiler velocity data collected in the approach channel of Brandon Road Lock and Dam in 2015

    Data.gov (United States)

    Department of the Interior — Water velocities were measured in the Des Plaines River from approximately river mile 286 to river mile 284 on October 19–21, 2015 using Teledyne Rio Grande 1200 kHz...

  2. Interactive volume exploration of petascale microscopy data streams using a visualization-driven virtual memory approach

    KAUST Repository

    Hadwiger, Markus

    2012-12-01

    This paper presents the first volume visualization system that scales to petascale volumes imaged as a continuous stream of high-resolution electron microscopy images. Our architecture scales to dense, anisotropic petascale volumes because it: (1) decouples construction of the 3D multi-resolution representation required for visualization from data acquisition, and (2) decouples sample access time during ray-casting from the size of the multi-resolution hierarchy. Our system is designed around a scalable multi-resolution virtual memory architecture that handles missing data naturally, does not pre-compute any 3D multi-resolution representation such as an octree, and can accept a constant stream of 2D image tiles from the microscopes. A novelty of our system design is that it is visualization-driven: we restrict most computations to the visible volume data. Leveraging the virtual memory architecture, missing data are detected during volume ray-casting as cache misses, which are propagated backwards for on-demand out-of-core processing. 3D blocks of volume data are only constructed from 2D microscope image tiles when they have actually been accessed during ray-casting. We extensively evaluate our system design choices with respect to scalability and performance, compare to previous best-of-breed systems, and illustrate the effectiveness of our system for real microscopy data from neuroscience. © 1995-2012 IEEE.

  3. Foodsheds in Virtual Water Flow Networks: A Spectral Graph Theory Approach

    Directory of Open Access Journals (Sweden)

    Nina Kshetry

    2017-06-01

    Full Text Available A foodshed is a geographic area from which a population derives its food supply, but a method to determine boundaries of foodsheds has not been formalized. Drawing on the food–water–energy nexus, we propose a formal network science definition of foodsheds by using data from virtual water flows, i.e., water that is virtually embedded in food. In particular, we use spectral graph partitioning for directed graphs. If foodsheds turn out to be geographically compact, it suggests the food system is local and therefore reduces energy and externality costs of food transport. Using our proposed method we compute foodshed boundaries at the global-scale, and at the national-scale in the case of two of the largest agricultural countries: India and the United States. Based on our determination of foodshed boundaries, we are able to better understand commodity flows and whether foodsheds are contiguous and compact, and other factors that impact environmental sustainability. The formal method we propose may be used more broadly to study commodity flows and their impact on environmental sustainability.

  4. Interactive Volume Exploration of Petascale Microscopy Data Streams Using a Visualization-Driven Virtual Memory Approach.

    Science.gov (United States)

    Hadwiger, M; Beyer, J; Jeong, Won-Ki; Pfister, H

    2012-12-01

    This paper presents the first volume visualization system that scales to petascale volumes imaged as a continuous stream of high-resolution electron microscopy images. Our architecture scales to dense, anisotropic petascale volumes because it: (1) decouples construction of the 3D multi-resolution representation required for visualization from data acquisition, and (2) decouples sample access time during ray-casting from the size of the multi-resolution hierarchy. Our system is designed around a scalable multi-resolution virtual memory architecture that handles missing data naturally, does not pre-compute any 3D multi-resolution representation such as an octree, and can accept a constant stream of 2D image tiles from the microscopes. A novelty of our system design is that it is visualization-driven: we restrict most computations to the visible volume data. Leveraging the virtual memory architecture, missing data are detected during volume ray-casting as cache misses, which are propagated backwards for on-demand out-of-core processing. 3D blocks of volume data are only constructed from 2D microscope image tiles when they have actually been accessed during ray-casting. We extensively evaluate our system design choices with respect to scalability and performance, compare to previous best-of-breed systems, and illustrate the effectiveness of our system for real microscopy data from neuroscience.

  5. Virtualization Security Combining Mandatory Access Control and Virtual Machine Introspection

    OpenAIRE

    Win, Thu Yein; Tianfield, Huaglory; Mair, Quentin

    2014-01-01

    Virtualization has become a target for attacks in cloud computing environments. Existing approaches to protecting the virtualization environment against the attacks are limited in protection scope and are with high overheads. This paper proposes a novel virtualization security solution which aims to provide comprehensive protection of the virtualization environment.

  6. Influence of approach velocity and mesh size on the entrainment and contact of a lowland river fish assemblage at a screened irrigation pump.

    Directory of Open Access Journals (Sweden)

    Craig A Boys

    Full Text Available Fish screens can help prevent the entrainment or injury of fish at irrigation diversions, but only when designed appropriately. Design criteria cannot simply be transferred between sites or pump systems and need to be developed using an evidence-based approach with the needs of local species in mind. Laboratory testing is typically used to quantify fish responses at intake screens, but often limits the number of species that can studied and creates artificial conditions not directly applicable to screens in the wild. In this study a field-based approach was used to assess the appropriateness of different screen design attributes for the protection of a lowland river fish assemblage at an experimental irrigation pump. Direct netting of entrained fish was used along with sonar technology to quantify the probability of screen contact for a Murray-Darling Basin (Australia fish species. Two approach velocities (0.1 and 0.5 m.sec(-1 and different sizes of woven mesh (5, 10 and 20 mm were evaluated. Smaller fish (<150 mm in the assemblage were significantly more susceptible to entrainment and screen contact, especially at higher approach velocities. Mesh size appeared to have little impact on screen contact and entrainment, suggesting that approach velocity rather than mesh size is likely to be the primary consideration when developing screens. Until the effects of screen contacts on injury and survival of these species are better understood, it is recommended that approach velocities not exceed 0.1 m.sec(-1 when the desire is to protect the largest range of species and size classes for lowland river fish assemblages in the Murray-Darling Basin. The field method tested proved to be a useful approach that could compliment laboratory studies to refine fish screen design and facilitate field validation.

  7. mRAISE: an alternative algorithmic approach to ligand-based virtual screening

    Science.gov (United States)

    von Behren, Mathias M.; Bietz, Stefan; Nittinger, Eva; Rarey, Matthias

    2016-08-01

    Ligand-based virtual screening is a well established method to find new lead molecules in todays drug discovery process. In order to be applicable in day to day practice, such methods have to face multiple challenges. The most important part is the reliability of the results, which can be shown and compared in retrospective studies. Furthermore, in the case of 3D methods, they need to provide biologically relevant molecular alignments of the ligands, that can be further investigated by a medicinal chemist. Last but not least, they have to be able to screen large databases in reasonable time. Many algorithms for ligand-based virtual screening have been proposed in the past, most of them based on pairwise comparisons. Here, a new method is introduced called mRAISE. Based on structural alignments, it uses a descriptor-based bitmap search engine (RAISE) to achieve efficiency. Alignments created on the fly by the search engine get evaluated with an independent shape-based scoring function also used for ranking of compounds. The correct ranking as well as the alignment quality of the method are evaluated and compared to other state of the art methods. On the commonly used Directory of Useful Decoys dataset mRAISE achieves an average area under the ROC curve of 0.76, an average enrichment factor at 1 % of 20.2 and an average hit rate at 1 % of 55.5. With these results, mRAISE is always among the top performing methods with available data for comparison. To access the quality of the alignments calculated by ligand-based virtual screening methods, we introduce a new dataset containing 180 prealigned ligands for 11 diverse targets. Within the top ten ranked conformations, the alignment closest to X-ray structure calculated with mRAISE has a root-mean-square deviation of less than 2.0 Å for 80.8 % of alignment pairs and achieves a median of less than 2.0 Å for eight of the 11 cases. The dataset used to rate the quality of the calculated alignments is freely available at

  8. Towards a Virtual Machine Approach to Resilient and Safe Mobile Robots

    DEFF Research Database (Denmark)

    Adam, Marian Sorin; Kuhrmann, Marco; Schultz, Ulrik Pagh

    2016-01-01

    , enabling a wide range of strategies for graceful degradation in the presence of partial failures. We use standard virtualization techniques as a flexible means to segregate the safety-critical parts of the system, combined with an automatically generated runtime monitoring component in charge of fast......Mobile robots are advanced systems that often need to operate in unstructured environments, which raises the complexity of the software. Many components are important for the overall reliability and safety of the robot, but reducing the risk of errors by making the software resilient is both...... complicated and expensive. Nevertheless, a commercially successful robot often has to remain safe while maintaining as much as possible from the required functionality, even in the presence of partial failures. In this paper, we propose a flexible way to improve the reliability of existing robot software...

  9. Using the Virtual Reality-Cognitive Rehabilitation Approach to Improve Contextual Processing in Children with Autism

    Directory of Open Access Journals (Sweden)

    Michelle Wang

    2013-01-01

    Full Text Available Background. This pilot study investigated the efficacy of a novel virtual reality-cognitive rehabilitation (VR-CR intervention to improve contextual processing of objects in children with autism. Previous research supports that children with autism show deficits in contextual processing, as well as deficits in its elementary components: abstraction and cognitive flexibility. Methods. Four children with autism participated in a multiple-baseline, single-subject study. The children were taught how to see objects in context by reinforcing attention to pivotal contextual information. Results. All children demonstrated statistically significant improvements in contextual processing and cognitive flexibility. Mixed results were found on the control test and changes in context-related behaviours. Conclusions. Larger-scale studies are warranted to determine the effectiveness and usability in comprehensive educational programs.

  10. Systemic Approach of a Virtual Enterprise that Constructs Wireless Payment Mechanisms

    Science.gov (United States)

    Assimakopoulos, Nikitas A.; Riggas, Anastasis N.; Kotsimpos, George K.

    2004-08-01

    Enterprises and Organizations are realizing that there are many win-win scenarios, for their customers and business partners, using the latest technology to enact convenient and secure purchases `over the air'. Wireless Payment (W/P) is the key element of Wireless Commerce. Businesses around the world are attempting to position themselves to operate in a highly competitive global economy. A single organization is often not able to develop sufficient internal design or production capabilities to respond effectively within a short period of time. The focus of this paper will be on the development and analysis of a Virtual Enterprise Architecture for the construction of W/P Mechanisms using Systemic Methodologies. A framework for the rapid and efficient integration of the business processes of the participating companies that construct W/P Mechanisms is provided.

  11. Using the virtual reality-cognitive rehabilitation approach to improve contextual processing in children with autism.

    Science.gov (United States)

    Wang, Michelle; Reid, Denise

    2013-01-01

    This pilot study investigated the efficacy of a novel virtual reality-cognitive rehabilitation (VR-CR) intervention to improve contextual processing of objects in children with autism. Previous research supports that children with autism show deficits in contextual processing, as well as deficits in its elementary components: abstraction and cognitive flexibility. Four children with autism participated in a multiple-baseline, single-subject study. The children were taught how to see objects in context by reinforcing attention to pivotal contextual information. All children demonstrated statistically significant improvements in contextual processing and cognitive flexibility. Mixed results were found on the control test and changes in context-related behaviours. Larger-scale studies are warranted to determine the effectiveness and usability in comprehensive educational programs.

  12. Brain-computer interface using P300 and virtual reality: A gaming approach for treating ADHD

    DEFF Research Database (Denmark)

    Rohani, Darius Adam; Sørensen, Helge Bjarup Dissing; Puthusserypady, Sadasivan

    2014-01-01

    and template-based features to detect these P300 responses. In an experimental setup using five subjects, an average error below 30% was achieved. To make it more challenging the BCI system has been embedded inside an immersive 3D virtual reality (VR) classroom with simulated distractions, which was created...... by combining a low-cost infrared camera and an “off-axis perspective projection” algorithm. This system is intended for kids by operating with four electrodes, as well as a non-intrusive VR setting. With the promising results, and considering the simplicity of the scheme, we hope to encourage future studies......This paper presents a novel brain-computer interface (BCI) system aiming at the rehabilitation of attention-deficit/hyperactive disorder in children. It uses the P300 potential in a series of feedback games to improve the subjects' attention. We applied a support vector machine (SVM) using temporal...

  13. Using the Virtual Reality-Cognitive Rehabilitation Approach to Improve Contextual Processing in Children with Autism

    Science.gov (United States)

    Reid, Denise

    2013-01-01

    Background. This pilot study investigated the efficacy of a novel virtual reality-cognitive rehabilitation (VR-CR) intervention to improve contextual processing of objects in children with autism. Previous research supports that children with autism show deficits in contextual processing, as well as deficits in its elementary components: abstraction and cognitive flexibility. Methods. Four children with autism participated in a multiple-baseline, single-subject study. The children were taught how to see objects in context by reinforcing attention to pivotal contextual information. Results. All children demonstrated statistically significant improvements in contextual processing and cognitive flexibility. Mixed results were found on the control test and changes in context-related behaviours. Conclusions. Larger-scale studies are warranted to determine the effectiveness and usability in comprehensive educational programs. PMID:24324379

  14. Cross-reactivity virtual profiling of the human kinome by X-react(KIN): a chemical systems biology approach.

    Science.gov (United States)

    Brylinski, Michal; Skolnick, Jeffrey

    2010-12-06

    Many drug candidates fail in clinical development due to their insufficient selectivity that may cause undesired side effects. Therefore, modern drug discovery is routinely supported by computational techniques, which can identify alternate molecular targets with a significant potential for cross-reactivity. In particular, the development of highly selective kinase inhibitors is complicated by the strong conservation of the ATP-binding site across the kinase family. In this paper, we describe X-React(KIN), a new machine learning approach that extends the modeling and virtual screening of individual protein kinases to a system level in order to construct a cross-reactivity virtual profile for the human kinome. To maximize the coverage of the kinome, X-React(KIN) relies solely on the predicted target structures and employs state-of-the-art modeling techniques. Benchmark tests carried out against available selectivity data from high-throughput kinase profiling experiments demonstrate that, for almost 70% of the inhibitors, their alternate molecular targets can be effectively identified in the human kinome with a high (>0.5) sensitivity at the expense of a relatively low false positive rate (human kinome are freely available to the academic community at http://cssb.biology.gatech.edu/kinomelhm/ .

  15. Virtual gap element approach for the treatment of non-matching interface using three-dimensional solid elements

    Science.gov (United States)

    Song, Yeo-Ul; Youn, Sung-Kie; Park, K. C.

    2017-10-01

    A method for three-dimensional non-matching interface treatment with a virtual gap element is developed. When partitioned structures contain curved interfaces and have different brick meshes, the discretized models have gaps along the interfaces. As these gaps bring unexpected errors, special treatments are required to handle the gaps. In the present work, a virtual gap element is introduced to link the frame and surface domain nodes in the frame work of the mortar method. Since the surface of the hexahedron element is quadrilateral, the gap element is pyramidal. The pyramidal gap element consists of four domain nodes and one frame node. Zero-strain condition in the gap element is utilized for the interpolation of frame nodes in terms of the domain nodes. This approach is taken to satisfy the momentum and energy conservation. The present method is applicable not only to curved interfaces with gaps, but also to flat interfaces in three dimensions. Several numerical examples are given to describe the effectiveness and accuracy of the proposed method.

  16. Molecular Modeling and Virtual Screening Approach to Discover Potential Antileishmanial Inhibitors Against Ornithine Decarboxylase.

    Science.gov (United States)

    Pandey, Rajan Kumar; Prajapati, Priyanka; Goyal, Sukriti; Grover, Abhinav; Prajapati, Vijay Kumar

    2016-01-01

    Visceral leishmaniasis (VL) is a tropical neglected disease, which encounters poorest of poor people living in Asia, Africa and Latin America; causing the mortality of more than 30,000 people worldwide. The armamentarium for the treatment of VL cases is limited and continuously facing decreasing of efficacy for existing drugs. Ornithine decarboxylase (ODC) is one of the interesting drug targets in Leishmania donovani, due to its association with redox metabolism. To search an antileishmanial compound showing the inhibitory effect against ornithine decarboxylase of Leishmania donovani Method: In this study, we have modelled the three dimensional structure of ODC using Phyre2 (Protein Homology/analog Y Recognition Engine V 2.0), followed by validation using VADAR (Volume, Area, Dihedral Angle Reporter), RAMPAGE, ERRAT, Verify3D and ProSA (Protein Structure Analysis). In order to develop potential antileishmanial, we conducted a high throughput virtual screening of ZINC database ligands comprising of 135,966 compounds. Furthermore, QikProp, ADMET predictor and MM-GBSA was performed for ADME (Absorption, Distribution, Metabolism and Elimination), toxicity and binding energy prediction for top ligands, respectively. Finally, molecular dynamics simulation was performed to get potential antileishmanial compounds. Screening of zinc database compounds using high throughput virtual screening has given twelve compounds with good inhibition activity against ornithine decarboxylase. Furthermore, the molecular dynamics simulation work reveals that ZINC67909154 could be a potent inhibitor and this compound can be used to combat VL disease Conclusion: This study concludes that ZINC67909154 has the great potential to inhibit L. donovani ODC and would add to the drug discovery process against visceral leishmaniasis. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  17. An innovative blended learning approach using virtual patients as preparation for skills laboratory training: perceptions of students and tutors

    Science.gov (United States)

    2013-01-01

    Background Currently only a few reports exist on how to prepare medical students for skills laboratory training. We investigated how students and tutors perceive a blended learning approach using virtual patients (VPs) as preparation for skills training. Methods Fifth-year medical students (N=617) were invited to voluntarily participate in a paediatric skills laboratory with four specially designed VPs as preparation. The cases focused on procedures in the laboratory using interactive questions, static and interactive images, and video clips. All students were asked to assess the VP design. After participating in the skills laboratory 310 of the 617 students were additionally asked to assess the blended learning approach through established questionnaires. Tutors’ perceptions (N=9) were assessed by semi-structured interviews. Results From the 617 students 1,459 VP design questionnaires were returned (59.1%). Of the 310 students 213 chose to participate in the skills laboratory; 179 blended learning questionnaires were returned (84.0%). Students provided high overall acceptance ratings of the VP design and blended learning approach. By using VPs as preparation, skills laboratory time was felt to be used more effectively. Tutors perceived students as being well prepared for the skills laboratory with efficient uses of time. Conclusion The overall acceptance of the blended learning approach was high among students and tutors. VPs proved to be a convenient cognitive preparation tool for skills training. PMID:23402663

  18. An innovative blended learning approach using virtual patients as preparation for skills laboratory training: perceptions of students and tutors.

    Science.gov (United States)

    Lehmann, Ronny; Bosse, Hans Martin; Simon, Anke; Nikendei, Christoph; Huwendiek, Sören

    2013-02-12

    Currently only a few reports exist on how to prepare medical students for skills laboratory training. We investigated how students and tutors perceive a blended learning approach using virtual patients (VPs) as preparation for skills training. Fifth-year medical students (N=617) were invited to voluntarily participate in a paediatric skills laboratory with four specially designed VPs as preparation. The cases focused on procedures in the laboratory using interactive questions, static and interactive images, and video clips. All students were asked to assess the VP design. After participating in the skills laboratory 310 of the 617 students were additionally asked to assess the blended learning approach through established questionnaires. Tutors' perceptions (N=9) were assessed by semi-structured interviews. From the 617 students 1,459 VP design questionnaires were returned (59.1%). Of the 310 students 213 chose to participate in the skills laboratory; 179 blended learning questionnaires were returned (84.0%). Students provided high overall acceptance ratings of the VP design and blended learning approach. By using VPs as preparation, skills laboratory time was felt to be used more effectively. Tutors perceived students as being well prepared for the skills laboratory with efficient uses of time. The overall acceptance of the blended learning approach was high among students and tutors. VPs proved to be a convenient cognitive preparation tool for skills training.

  19. Predicting the liquefaction phenomena from shear velocity profiling: Empirical approach to 6.3 Mw, May 2006 Yogyakarta earthquake

    Science.gov (United States)

    Hartantyo, Eddy; Brotopuspito, Kirbani S.; Sismanto, Waluyo

    2015-04-01

    The liquefactions phenomena have been reported after a shocking 6.5Mw earthquake hit Yogyakarta province in the morning at 27 May 2006. Several researchers have reported the damage, casualties, and soil failure due to the quake, including the mapping and analyzing the liquefaction phenomena. Most of them based on SPT test. The study try to draw the liquefaction susceptibility by means the shear velocity profiling using modified Multichannel Analysis of Surface Waves (MASW). This paper is a preliminary report by using only several measured MASW points. The study built 8-channel seismic data logger with 4.5 Hz geophones for this purpose. Several different offsets used to record the high and low frequencies of surface waves. The phase-velocity diagrams were stacked in the frequency domain rather than in time domain, for a clearer and easier dispersion curve picking. All codes are implementing in Matlab. From these procedures, shear velocity profiling was collected beneath each geophone's spread. By mapping the minimum depth of shallow water table, calculating PGA with soil classification, using empirical formula for saturated soil weight from shear velocity profile, and calculating CRR and CSR at every depth, the liquefaction characteristic can be identify in every layer. From several acquired data, a liquefiable potential at some depth below water table was obtained.

  20. Predicting the liquefaction phenomena from shear velocity profiling: Empirical approach to 6.3 Mw, May 2006 Yogyakarta earthquake

    Energy Technology Data Exchange (ETDEWEB)

    Hartantyo, Eddy, E-mail: hartantyo@ugm.ac.id [PhD student, Physics Department, FMIPA, UGM. Sekip Utara Yogyakarta 55281 Indonesia (Indonesia); Brotopuspito, Kirbani S.; Sismanto; Waluyo [Geophysics Laboratory, FMIPA, Universitas Gadjah Mada, Sekip Utara Yogyakarta 55281 (Indonesia)

    2015-04-24

    The liquefactions phenomena have been reported after a shocking 6.5Mw earthquake hit Yogyakarta province in the morning at 27 May 2006. Several researchers have reported the damage, casualties, and soil failure due to the quake, including the mapping and analyzing the liquefaction phenomena. Most of them based on SPT test. The study try to draw the liquefaction susceptibility by means the shear velocity profiling using modified Multichannel Analysis of Surface Waves (MASW). This paper is a preliminary report by using only several measured MASW points. The study built 8-channel seismic data logger with 4.5 Hz geophones for this purpose. Several different offsets used to record the high and low frequencies of surface waves. The phase-velocity diagrams were stacked in the frequency domain rather than in time domain, for a clearer and easier dispersion curve picking. All codes are implementing in Matlab. From these procedures, shear velocity profiling was collected beneath each geophone’s spread. By mapping the minimum depth of shallow water table, calculating PGA with soil classification, using empirical formula for saturated soil weight from shear velocity profile, and calculating CRR and CSR at every depth, the liquefaction characteristic can be identify in every layer. From several acquired data, a liquefiable potential at some depth below water table was obtained.

  1. Optimal peak systolic velocity threshold at duplex US for determining the need for carotid practice endarterectomy : A decision analytic approach

    NARCIS (Netherlands)

    Heijenbrok-Kal, M.H.; Buskens, E.; Nederkoorn, P.J.; van der Graaf, Y.; Hunink, M.G.M.

    2006-01-01

    Purpose: To determine the optimal peak systolic velocity (PSV) threshold at duplex ultrasonography (US) required to establish the need for carotid endarterectomy in symptomatic patients on the basis of the long-term cost-effectiveness outcomes of diagnostic testing and subsequent treatment.

  2. Organizaciones Virtuales Organizaciones Virtuales

    Directory of Open Access Journals (Sweden)

    Gladis Cecilia Villegas Arias

    2003-06-01

    Full Text Available Virtual Organizations are new organizational forms originated from both the replacementof face to face communications by remote communications supported by electronic means,and from the accesibility of real time information about the operation of the company, forall employees.This article pursues the following goals: 1 To define virtual organization, review its sociotechnical antecedents and propose a preliminary classification into inter-organizationaland intra-organizational forms.  2 To discuss the characteristics of virtual organizationsand their impact on organizational design, and 3 To compare virtual organizations toother organizational forms.Las organizaciones virtuales son formas organizativas nuevas, que resultan de: primero, reemplazar las interacciones cara a cara con interacciones remotas, soportadas por comunicaciones electrónicas y segundo,  proveer acceso en tiempo real a toda la información de la empresa para todos los trabajadores.En este artículo se busca: 1 Definir organización virtual, revisar sus antecedentes y proponeruna clasificación básica preliminar de las mismas  2 Discutir las características de las organizaciones virtuales y sus implicaciones para el diseño organizativo 3 Comparar estaforma organizativa a las formas organizativas no virtuales.

  3. Nuclear velocity perturbation theory for vibrational circular dichroism: An approach based on the exact factorization of the electron-nuclear wave function

    CERN Document Server

    Scherrer, Arne; Sebastiani, Daniel; Gross, E K U; Vuilleumier, Rodolphe

    2015-01-01

    The nuclear velocity perturbation current-density theory (NVPT) for vibrational circular dichroism (VCD) is derived from the exact factorization of the electron-nuclear wave function. This new formalism offers an exact starting point to include correction terms to the Born-Oppenheimer (BO) form of the molecular wave function, similarly to the complete-adiabatic approximation. The corrections depend on a small parameter that, in a classical treatment of the nuclei, is identified as the nuclear velocity. Apart from proposing a rigorous basis for the NVPT, we show that the rotational strength, related to the intensity of the VCD signal, contain a new contribution beyond-BO that can be evaluated with the NVPT and that only arises when the exact factorization approach is employed. Numerical results are presented for chiral and non-chiral systems to test the validity of the approach.

  4. Deflection corridors of abdomen and thorax in oblique side impacts using equal stress equal velocity approach: comparison with other normalization methods.

    Science.gov (United States)

    Yoganandan, Narayan; Arun, Mike W J; Humm, John; Pintar, Frank A

    2014-10-01

    The first objective of the study was to determine the thorax and abdomen deflection time corridors using the equal stress equal velocity approach from oblique side impact sled tests with postmortem human surrogates fitted with chestbands. The second purpose of the study was to generate deflection time corridors using impulse momentum methods and determine which of these methods best suits the data. An anthropometry-specific load wall was used. Individual surrogate responses were normalized to standard midsize male anthropometry. Corridors from the equal stress equal velocity approach were very similar to those from impulse momentum methods, thus either method can be used for this data. Present mean and plus/minus one standard deviation abdomen and thorax deflection time corridors can be used to evaluate dummies and validate complex human body finite element models.

  5. Quantification of virtual slides: Approaches to analysis of content-based image information

    Directory of Open Access Journals (Sweden)

    Klaus Kayser

    2011-01-01

    Full Text Available Virtual microscopy, which is the diagnostic work on completely digitized histological and cytological slides as well as blood smears, is at the stage to be implemented in routine diagnostic surgical pathology (tissue-based diagnosis in the near future, once it has been accepted by the US Food and Drug Administration. The principle of content-based image information, its mandatory prerequisites to obtain reproducible and stable image information as well as the different compartments that contribute to image information are described in detail. Automated extraction of content-based image information requires shading correction, constant maximum of grey values, and standardized grey value histograms. The different compartments to evaluate image information include objects, structure, and texture. Identification of objects and derived structure depend on segmentation accuracy and applied procedures; textures contain pixel-based image information only. All together, these image compartments posses the discrimination power to distinguish between object space and background, and, in addition, to reproducibly define regions of interest (ROIs. ROIs are image areas which display the information that is of preferable interest to the viewing pathologist. They contribute to the derived diagnosis to a higher level when compared with other image areas. The implementation of content-based image information algorithms to be applied for predictive tissue-based diagnoses is described in detail.

  6. Towards understanding the myometrial physiome: approaches for the construction of a virtual physiological uterus.

    Science.gov (United States)

    Taggart, Michael John; Blanks, Andrew; Kharche, Sanjay; Holden, Arun; Wang, Bin; Zhang, Henggui

    2007-06-01

    Premature labour (PTL) is the single most significant factor contributing to neonatal morbidity in Europe with enormous attendant healthcare and social costs. Consequently, it remains a major challenge to alleviate the cause and impact of this condition. Our ability to improve the diagnosis and treatment of women most at risk of PTL is, however, actually hampered by an incomplete understanding of the ways in which the functions of the uterine myocyte are integrated to effect an appropriate biological response at the multicellular whole organ system. The level of organization required to co-ordinate labouring uterine contractile effort in time and space can be considered immense. There is a multitude of what might be considered mini-systems involved, each with their own regulatory feedback cycles, yet they each, in turn, will influence the behaviour of a related system. These include, but are not exclusive to, gestational-dependent regulation of transcription, translation, post-translational modifications, intracellular signaling dynamics, cell morphology, intercellular communication and tissue level morphology. We propose that in order to comprehend how these mini-systems integrate to facilitate uterine contraction during labour (preterm or term) we must, in concert with biological experimentation, construct detailed mathematical descriptions of our findings. This serves three purposes: firstly, providing a quantitative description of series of complex observations; secondly, proferring a database platform that informs further testable experimentation; thirdly, advancing towards the establishment of a virtual physiological uterus and in silico clinical diagnosis and treatment of PTL.

  7. a Virtual Hub Brokering Approach for Integration of Historical and Modern Maps

    Science.gov (United States)

    Bruno, N.; Previtali, M.; Barazzetti, L.; Brumana, R.; Roncella, R.

    2016-06-01

    Geospatial data are today more and more widespread. Many different institutions, such as Geographical Institutes, Public Administrations, collaborative communities (e.g., OSM) and web companies, make available nowadays a large number of maps. Besides this cartography, projects of digitizing, georeferencing and web publication of historical maps have increasingly spread in the recent years. In spite of these variety and availability of data, information overload makes difficult their discovery and management: without knowing the specific repository where the data are stored, it is difficult to find the information required and problems of interconnection between different data sources and their restricted interoperability limit a wide utilization of available geo-data. This paper aims to describe some actions performed to assure interoperability between data, in particular spatial and geographic data, gathered from different data providers, with different features and referring to different historical periods. The article summarizes and exemplifies how, starting from projects of historical map digitizing and Historical GIS implementation, respectively for the Lombardy and for the city of Parma, the interoperability is possible in the framework of the ENERGIC OD project. The European project ENERGIC OD, thanks to a specific component - the virtual hub - based on a brokering framework, copes with the previous listed problems and allows the interoperability between different data sources.

  8. An Experiment to Analyze Performance of Virtual Private Network Approach to Information Exchange between Health Facilities

    Directory of Open Access Journals (Sweden)

    Siphael BETUEL

    2017-06-01

    Full Text Available In developing countries, Tanzania in particular, studies and reports have depicted that there is a strong desire and need for seamless information exchange across health care providing facilities. A limited study conducted in few public and private hospitals has also revealed the same. On the other hand, the eHealth community has failed to effectively take advantage of the advances in technologies to make that desire come true. One potential technology is Virtual Private Network (VPN for which it has been noticed that there is a misconception and lack of innovative initiatives that slow down its uptake in eHealth. This article presents a technical assessment of the VPN technology in Tanzanian context. Primarily, the assessment focused on practicability of the best VPN practices and the perceived user experience performance when VPN is in use. It was observed that the response time dropped significantly as expected. The increase in response time and computer memory utilization is due to security mechanisms that are involved in VPN, the stronger security is used the more performance decreases. However, the increase in response time and computer memory utilization is very small in such a way that users will not be able to notice.

  9. A Drone Remote Sensing for Virtual Reality Simulation System for Forest Fires: Semantic Neural Network Approach

    Science.gov (United States)

    Narasimha Rao, Gudikandhula; Jagadeeswara Rao, Peddada; Duvvuru, Rajesh

    2016-09-01

    Wild fires have significant impact on atmosphere and lives. The demand of predicting exact fire area in forest may help fire management team by using drone as a robot. These are flexible, inexpensive and elevated-motion remote sensing systems that use drones as platforms are important for substantial data gaps and supplementing the capabilities of manned aircraft and satellite remote sensing systems. In addition, powerful computational tools are essential for predicting certain burned area in the duration of a forest fire. The reason of this study is to built up a smart system based on semantic neural networking for the forecast of burned areas. The usage of virtual reality simulator is used to support the instruction process of fire fighters and all users for saving of surrounded wild lives by using a naive method Semantic Neural Network System (SNNS). Semantics are valuable initially to have a enhanced representation of the burned area prediction and better alteration of simulation situation to the users. In meticulous, consequences obtained with geometric semantic neural networking is extensively superior to other methods. This learning suggests that deeper investigation of neural networking in the field of forest fires prediction could be productive.

  10. Smart sensors and virtual physiology human approach as a basis of personalized therapies in diabetes mellitus.

    Science.gov (United States)

    Fernández Peruchena, Carlos M; Prado-Velasco, Manuel

    2010-01-01

    Diabetes mellitus (DM) has a growing incidence and prevalence in modern societies, pushed by the aging and change of life styles. Despite the huge resources dedicated to improve their quality of life, mortality and morbidity rates, these are still very poor. In this work, DM pathology is revised from clinical and metabolic points of view, as well as mathematical models related to DM, with the aim of justifying an evolution of DM therapies towards the correction of the physiological metabolic loops involved. We analyze the reliability of mathematical models, under the perspective of virtual physiological human (VPH) initiatives, for generating and integrating customized knowledge about patients, which is needed for that evolution. Wearable smart sensors play a key role in this frame, as they provide patient's information to the models.A telehealthcare computational architecture based on distributed smart sensors (first processing layer) and personalized physiological mathematical models integrated in Human Physiological Images (HPI) computational components (second processing layer), is presented. This technology was designed for a renal disease telehealthcare in earlier works and promotes crossroads between smart sensors and the VPH initiative. We suggest that it is able to support a truly personalized, preventive, and predictive healthcare model for the delivery of evolved DM therapies.

  11. Empirical evaluation of a virtual laboratory approach to teach lactate dehydrogenase enzyme kinetics.

    Science.gov (United States)

    Booth, Christine; Cheluvappa, Rajkumar; Bellinson, Zack; Maguire, Danni; Zimitat, Craig; Abraham, Joyce; Eri, Rajaraman

    2016-06-01

    Personalised instruction is increasingly recognised as crucial for efficacious learning today. Our seminal work delineates and elaborates on the principles, development and implementation of a specially-designed adaptive, virtual laboratory. We strived to teach laboratory skills associated with lactate dehydrogenase (LDH) enzyme kinetics to 2nd-year biochemistry students using our adaptive learning platform. Pertinent specific aims were to:(1)design/implement a web-based lesson to teach lactate dehydrogenase(LDH) enzyme kinetics to 2nd-year biochemistry students(2)determine its efficacious in improving students' comprehension of enzyme kinetics(3)assess their perception of its usefulness/manageability(vLab versus Conventional Tutorial). Our tools were designed using HTML5 technology. We hosted the program on an adaptive e-learning platform (AeLP). Provisions were made to interactively impart informed laboratory skills associated with measuring LDH enzyme kinetics. A series of e-learning methods were created. Tutorials were generated for interactive teaching and assessment. The learning outcomes herein were on par with that from a conventional classroom tutorial. Student feedback showed that the majority of students found the vLab learning experience "valuable"; and the vLab format/interface "well-designed". However, there were a few technical issues with the 1st roll-out of the platform. Our pioneering effort resulted in productive learning with the vLab, with parity with that from a conventional tutorial. Our contingent discussion emphasises not only the cornerstone advantages, but also the shortcomings of the AeLP method utilised. We conclude with an astute analysis of possible extensions and applications of our methodology.

  12. Determination of maximum aerobic velocity by a five minute test with reference to running world records. A theoretical approach.

    Science.gov (United States)

    Chamoux, A; Berthon, P; Laubignat, J F

    1996-01-01

    Field measurement of the maximal aerobic velocity (MAV) is closely linked to effort-duration then to the used protocol. We construct the relationship between running speed and running-duration logarithm from running world records. It appears a noteworthy point at 4.97 minutes, to be suggested as MAV duration point. By agreement, MAV could be measured on field by a five minute test whatever the sport may be.

  13. Using the Spanish Online Resource "Aula Virtual de Espanol" (AVE) to Promote a Blended Teaching Approach in High School Spanish Language Classrooms

    Science.gov (United States)

    Pellerin, Martine; Montes, Carlos Soler

    2012-01-01

    The study explores the effectiveness of the implementation of blended teaching (BT) by combining the Spanish online resource "Aula Virtual de Espanol" (AVE) with the face-to-face (F2F) delivery approach in second language Spanish programs in two high schools in Alberta, Canada. Findings demonstrate the effectiveness of combining the…

  14. Combined effects of Mass and Velocity on forward displacement and phenomenological ratings: a functional measurement approach to the Momentum metaphor

    Directory of Open Access Journals (Sweden)

    Michel-Ange Amorim

    2010-01-01

    Full Text Available Representational Momentum (RepMo refers to the phenomenon that the vanishing position of a moving target is perceived as displaced ahead in the direction of movement. Originally taken to reflect a strict internalization of physical momentum, the finding that the target implied mass did not have an effect led to its subsequent reinterpretation as a second-order isomorphism between mental representations and principles of the physical world. However, very few studies have addressed the effects of mass on RepMo, and consistent replications of the null effect are lacking. The extent of motor engagement of the observers in RepMo tasks has, on the other hand, been suggested to determine the occurrence of the phenomenon; however, no systematic investigations were made of the degree to which it might modulate the effect of target mass. In the present work, we use Information Integration Theory to study the joint effects of different motor responses, target velocity and target mass on RepMo, and also of velocity and target mass on rating responses. Outcomes point not only to an effect of mass on RepMo, as to a differential effect of response modality on kinematic (e.g., velocity and dynamic (e.g., mass variables. Comparisons of patterns of mislocalisation with phenomenological ratings suggest that simplification of physical principles, rather than strict internalization or isomorphism per se, might underlie RepMo.

  15. Distinguished hyperbolic trajectories in time-dependent fluid flows: analytical and computational approach for velocity fields defined as data sets

    Directory of Open Access Journals (Sweden)

    K. Ide

    2002-01-01

    Full Text Available In this paper we develop analytical and numerical methods for finding special hyperbolic trajectories that govern geometry of Lagrangian structures in time-dependent vector fields. The vector fields (or velocity fields may have arbitrary time dependence and be realized only as data sets over finite time intervals, where space and time are discretized. While the notion of a hyperbolic trajectory is central to dynamical systems theory, much of the theoretical developments for Lagrangian transport proceed under the assumption that such a special hyperbolic trajectory exists. This brings in new mathematical issues that must be addressed in order for Lagrangian transport theory to be applicable in practice, i.e. how to determine whether or not such a trajectory exists and, if it does exist, how to identify it in a sequence of instantaneous velocity fields. We address these issues by developing the notion of a distinguished hyperbolic trajectory (DHT. We develop an existence criteria for certain classes of DHTs in general time-dependent velocity fields, based on the time evolution of Eulerian structures that are observed in individual instantaneous fields over the entire time interval of the data set. We demonstrate the concept of DHTs in inhomogeneous (or "forced" time-dependent linear systems and develop a theory and analytical formula for computing DHTs. Throughout this work the notion of linearization is very important. This is not surprising since hyperbolicity is a "linearized" notion. To extend the analytical formula to more general nonlinear time-dependent velocity fields, we develop a series of coordinate transforms including a type of linearization that is not typically used in dynamical systems theory. We refer to it as Eulerian linearization, which is related to the frame independence of DHTs, as opposed to the Lagrangian linearization, which is typical in dynamical systems theory, which is used in the computation of Lyapunov exponents. We

  16. Reducing Deadline Miss Rate for Grid Workloads running in Virtual Machines: a deadline-aware and adaptive approach

    CERN Document Server

    Khalid, Omer; Anthony, Richard; Petridis, Miltos

    2011-01-01

    This thesis explores three major areas of research; integration of virutalization into sci- entific grid infrastructures, evaluation of the virtualization overhead on HPC grid job’s performance, and optimization of job execution times to increase their throughput by reducing job deadline miss rate. Integration of the virtualization into the grid to deploy on-demand virtual machines for jobs in a way that is transparent to the end users and have minimum impact on the existing system poses a significant challenge. This involves the creation of virtual machines, decompression of the operating system image, adapting the virtual environ- ment to satisfy software requirements of the job, constant update of the job state once it’s running with out modifying batch system or existing grid middleware, and finally bringing the host machine back to a consistent state. To facilitate this research, an existing and in production pilot job framework has been modified to deploy virtual machines on demand on the grid using...

  17. A Cross-Entropy-Based Admission Control Optimization Approach for Heterogeneous Virtual Machine Placement in Public Clouds

    OpenAIRE

    Li Pan; Datao Wang

    2016-01-01

    Virtualization technologies make it possible for cloud providers to consolidate multiple IaaS provisions into a single server in the form of virtual machines (VMs). Additionally, in order to fulfill the divergent service requirements from multiple users, a cloud provider needs to offer several types of VM instances, which are associated with varying configurations and performance, as well as different prices. In such a heterogeneous virtual machine placement process, one significant problem f...

  18. Multimedia and co-operative work in new product development : A participatory approach to virtual prototyping

    NARCIS (Netherlands)

    Muller, P; vanEngelen, J; Terlouw, P; deVreede, GJ

    1996-01-01

    In order to be successful, nov product development requires a balance between market pull and technology push. On a project level this involves forging a link between the (technical) capabilities of the company and the needs of the market place. This paper describes an approach to forge this link

  19. On Virtual Face-Work: An Ethnography of Communication Approach to a Live Chat Reference Interaction

    Science.gov (United States)

    Radford, Marie L.; Radford, Gary P.; Connaway, Lynn Silipigni; DeAngelis, Jocelyn A.

    2011-01-01

    Erving Goffman's theoretical framework and concept of face-work has the potential to greatly increase the understanding of interpersonal dynamics in computer-mediated communication realms. This research used an ethnography of communication approach and the concept of face-work to analyze the transcript of an interaction between a librarian and a…

  20. Developing Digital Courseware for a Virtual Nano-Biotechnology Laboratory: A Design-Based Research Approach

    Science.gov (United States)

    Yueh, Hsiu-Ping; Chen, Tzy-Ling; Lin, Weijane; Sheen, Horn-Jiunn

    2014-01-01

    This paper first reviews applications of multimedia in engineering education, especially in laboratory learning. It then illustrates a model and accreditation criteria adopted for developing a specific set of nanotechnology laboratory courseware and reports the design-based research approach used in designing and developing the e-learning…

  1. Comparative Analysis of Virtual Screening Approaches in the Search for Novel EphA2 Receptor Antagonists

    Directory of Open Access Journals (Sweden)

    Donatella Callegari

    2015-09-01

    Full Text Available The EphA2 receptor and its ephrin-A1 ligand form a key cell communication system, which has been found overexpressed in many cancer types and involved in tumor growth. Recent medicinal chemistry efforts have identified bile acid derivatives as low micromolar binders of the EphA2 receptor. However, these compounds suffer from poor physicochemical properties, hampering their use in vivo. The identification of compounds able to disrupt the EphA2-ephrin-A1 complex lacking the bile acid scaffold may lead to new pharmacological tools suitable for in vivo studies. To identify the most promising virtual screening (VS protocol aimed at finding novel EphA2 antagonists, we investigated the ability of both ligand-based and structure-based approaches to retrieve known EphA2 antagonists from libraries of decoys with similar molecular properties. While ligand-based VSs were conducted using UniPR129 and ephrin-A1 ligand as reference structures, structure-based VSs were performed with Glide, using the X-ray structure of the EphA2 receptor/ephrin-A1 complex. A comparison of enrichment factors showed that ligand-based approaches outperformed the structure-based ones, suggesting ligand-based methods using the G-H loop of ephrin-A1 ligand as template as the most promising protocols to search for novel EphA2 antagonists.

  2. Virtual muscle: a computational approach to understanding the effects of muscle properties on motor control.

    Science.gov (United States)

    Cheng, E J; Brown, I E; Loeb, G E

    2000-09-15

    This paper describes a computational approach to modeling the complex mechanical properties of muscles and tendons under physiological conditions of recruitment and kinematics. It is embodied as a software package for use with Matlab and Simulink that allows the creation of realistic musculotendon elements for use in motor control simulations. The software employs graphic user interfaces (GUI) and dynamic data exchange (DDE) to facilitate building custom muscle model blocks and linking them to kinetic analyses of complete musculoskeletal systems. It is scalable in complexity and accuracy. The model is based on recently published data on muscle and tendon properties measured in feline slow- and fast-twitch muscle, and incorporates a novel approach to simulating recruitment and frequency modulation of different fiber-types in mixed muscles. This software is distributed freely over the Internet at http://ami.usc.edu/mddf/virtualmuscle.

  3. E-learning on the job : training taking a more virtual approach

    Energy Technology Data Exchange (ETDEWEB)

    Macedo, R.

    2008-07-15

    A growing number of companies are using web-based e-learning systems to train employees. The activities of 3 E-learning companies were described in this article, notably dominKnow Learning Systems, NGRAIN Corporation and Blatant Media. One of the greatest challenges facing the oilsands industry is to build a skilled labour force to operate massive upgraders. The benefit of the e-learning approach is that consistent information can be delivered to learners, with no variation in information. The training takes on many forms, either through online simulations or simply placing a manual online. In addition to saving time, e-learning familiarizes workers with specific pieces of equipment that would be much too expensive to purchase. Three-dimensional equipment simulations are also made available for training purposes. This article presented an online e-learning approach that has been used effectively for safety training and corporate governance. E-learning simplified the process compared to actual classroom training. It allowed staff to combine training time with regular work schedules. The online e-learning approach was shown to save companies many of hours in training time. 2 figs.

  4. A new approach for the determination of cementation exponent in different petrofacies with velocity deviation logs and petrographical studies in the carbonate Asmari formation

    Science.gov (United States)

    Kazemzadeh, E.; Nabi-Bidhendi, M.; Keramati Moezabad, M.; Rezaee, M. R.; Saadat, K.

    2007-06-01

    This study was carried out to develop an approach applicable for the determination of the cementation exponent in Archie's formula for complex carbonate reservoirs. Evaluation of hydrocarbon saturation is very important in oil reservoir studies. Archie's are the basic equations for saturation evaluation. The coefficients in these equations are normally determined from laboratory data. Archie presented values for these coefficients, which are constants for a sandstone lithology. Because carbonate rocks show drastic variations in lithology due to different texture and pore types, Archie's coefficients, which are more influenced by pore type, should be determined for different types of carbonate. Uncertainties in these coefficients cause many errors in saturation evaluation, especially for oil in situ. The value of the cementation exponent is the main factor that can cause error in saturation determination. In this study, Archie's parameters (a and m) were determined in the laboratory for various petrofacies based on both petrographic studies and CT images. Due to the high dependence of seismic wave velocity on pore shape in carbonate rocks, petrofacies were also determined by using wave velocity deviation logs. Archie's parameters were then determined for each petrofacies. The results showed that cementation exponent increases in value with increasing velocity deviation values. It is concluded that the correlation coefficient for different petrofacies obtained from velocity deviation logs is comparatively higher than that obtained solely from petrographic studies. Considering the fact that petrophysical data are more accessible than core-based petrography data, the method presented in this study appears to provide a more useful approach in determining Archie's coefficients.

  5. Virtual colonoscopy

    Science.gov (United States)

    Colonoscopy - virtual; CT colonography; Computed tomographic colonography; Colography - virtual ... Differences between virtual and conventional colonoscopy include: VC can view the colon from many different angles. This is not as easy ...

  6. Virtual Interactive Space (VIS)

    DEFF Research Database (Denmark)

    Brooks, Anthony Lewis

    2015-01-01

    This paper shares code that enables the making of a Virtual Interactive Space (VIS) where the skin of the invisible active sensor area is dynamically responsive to the velocity of a limb e.g. hand. Used in proprioception training of movement the patch is at the core of the author’s Reafferentation...

  7. An alternative approach to describing agility in sports through establishment of a relationship between velocity and radius of curvature.

    Science.gov (United States)

    Arshi, Ahmed Reza; Nabavi, Hoda; Mehdizadeh, Sina; Davids, Keith

    2015-01-01

    Agility is an essential part of many athletic activities. Currently, agility drill duration is the sole criterion used for evaluation of agility performance. The relationship between drill duration and factors such as acceleration, deceleration and change of direction, however, has not been fully explored. This paper provides a mathematical description of the relationship between velocity and radius of curvatures in an agility drill through implementation of a power law (PL). Two groups of skilled and unskilled participants performed a cyclic forward/backward shuttle agility test. Kinematic data was recorded using motion capture system at a sampling rate of 200 Hz. The logarithmic relationship between tangential velocity and radius of curvature of participant trajectories in both groups was established using the PL. The slope of the regression line was found to be 0.26 and 0.36, for the skilled and unskilled groups, respectively. The magnitudes of regression line slope for both groups were approximately 0.3 which is close to the expected 1/3 value. Results are an indication of how the PL could be implemented in an agility drill thus opening the way for establishment of a more representative measure of agility performance instead of drill duration.

  8. Durable ideas in software engineering concepts, methods and approaches from my virtual toolbox

    CERN Document Server

    J Cusick, James

    2013-01-01

    ""Software Engineering now occupies a central place in the development of technology and in the advancement of the economy. From telecommunications to aerospace and from cash registers to medical imaging, software plays a vital and often decisive role in the successful accomplishment of a variety of projects. The creation of software requires a variety of techniques, tools, and especially, properly skilled engineers. This e-book focuses on core concepts and approaches that have proven useful to the author time and time again on many industry projects over a quarter century of research, develo

  9. Creating Virtual Sources Inside an Unknown Medium from Reflection Data : A New Approach to Internal Multiple Elimination

    NARCIS (Netherlands)

    Wapenaar, C.P.A.; Thorbecke, J.W.; Van der Neut, J.R.; Broggini, F.; Snieder, R.

    2012-01-01

    It has recently been shown that the response to a virtual source in the subsurface can be derived from reflection data at the surface and an estimate of the direct arrivals between the virtual source and the surface. Hence, unlike for seismic interferometry, no receivers are needed inside the

  10. Exploring Learning Performance toward Cognitive Approaches of a Virtual Companion System in LINE App for m-Learning

    Science.gov (United States)

    Hsieh, Sheng-Wen; Wu, Min-Ping

    2013-01-01

    This paper used a Virtual Companion System (VCS) to examine how specific design variables within virtual learning companion affect the learning process of learners as defined by the cognitive continuum of field-dependent, field-independent and field-mixed learners in LINE app for m-learning. The data were collected from 198 participants in a…

  11. LOW-VELOCITY COMPRESSIBLE FLOW THEORY

    Science.gov (United States)

    The widespread application of incompressible flow theory dominates low-velocity fluid dynamics, virtually preventing research into compressible low-velocity flow dynamics. Yet, compressible solutions to simple and well-defined flow problems and a series of contradictions in incom...

  12. Novel virtual screening approach for the discovery of human tyrosinase inhibitors.

    Science.gov (United States)

    Ai, Ni; Welsh, William J; Santhanam, Uma; Hu, Hong; Lyga, John

    2014-01-01

    Tyrosinase is the key enzyme involved in the human pigmentation process, as well as the undesired browning of fruits and vegetables. Compounds inhibiting tyrosinase catalytic activity are an important class of cosmetic and dermatological agents which show high potential as depigmentation agents used for skin lightening. The multi-step protocol employed for the identification of novel tyrosinase inhibitors incorporated the Shape Signatures computational algorithm for rapid screening of chemical libraries. This algorithm converts the size and shape of a molecule, as well its surface charge distribution and other bio-relevant properties, into compact histograms (signatures) that lend themselves to rapid comparison between molecules. Shape Signatures excels at scaffold hopping across different chemical families, which enables identification of new actives whose molecular structure is distinct from other known actives. Using this approach, we identified a novel class of depigmentation agents that demonstrated promise for skin lightening product development.

  13. Novel virtual screening approach for the discovery of human tyrosinase inhibitors.

    Directory of Open Access Journals (Sweden)

    Ni Ai

    Full Text Available Tyrosinase is the key enzyme involved in the human pigmentation process, as well as the undesired browning of fruits and vegetables. Compounds inhibiting tyrosinase catalytic activity are an important class of cosmetic and dermatological agents which show high potential as depigmentation agents used for skin lightening. The multi-step protocol employed for the identification of novel tyrosinase inhibitors incorporated the Shape Signatures computational algorithm for rapid screening of chemical libraries. This algorithm converts the size and shape of a molecule, as well its surface charge distribution and other bio-relevant properties, into compact histograms (signatures that lend themselves to rapid comparison between molecules. Shape Signatures excels at scaffold hopping across different chemical families, which enables identification of new actives whose molecular structure is distinct from other known actives. Using this approach, we identified a novel class of depigmentation agents that demonstrated promise for skin lightening product development.

  14. Image Based Rendering and Virtual Reality

    DEFF Research Database (Denmark)

    Livatino, Salvatore

    The Presentation concerns with an overview of Image Based Rendering approaches and their use on Virtual Reality, including Virtual Photography and Cinematography, and Mobile Robot Navigation.......The Presentation concerns with an overview of Image Based Rendering approaches and their use on Virtual Reality, including Virtual Photography and Cinematography, and Mobile Robot Navigation....

  15. Virtual cellular manufacturing system based on resource element approach and analyzing its performance over different basic layouts

    Directory of Open Access Journals (Sweden)

    G. R. Esmaeilian

    2012-01-01

    Full Text Available This research aims to present how choosing a suitable layout can improve the performance of virtual cellular manufacturing systems (VCMSs, especially minimizing the material flow between machines required by each family group. To present the efficacy of basic layouts on performances of VCMSs, a multi-objective mathematical model with a goal programming (GP approach is developed to generate VCMSs based on resource-elements (REs. The formulated model is coded in Lingo software and is run over functional and distributed arrangements of the same machines. The performance and the validity of the developed model are checked by a numerical example taken from the literature. The objective function of the mathematical model is measured for that example over two mentioned layout to compare the performance of the generated systems. Moreover, because of the material handling costs importance, material flows are measured to find the best option as a basic layout for VCMSs. To compare the performance of the generated system with the classical cellular manufacturing system (CMS, cell capacity utilization (CCU is employed as an independent criterion to evaluate each system. The result illustrates the priority of distributed layouts for generating RE-based VCMSs because of its flexibility, minimizing the objective function for the mathematical model, and smaller material flow by the components. In addition, the generated VCMSs outperforms the classical CMS from the CCU point of view.

  16. Discovery of Novel Inhibitors for Nek6 Protein through Homology Model Assisted Structure Based Virtual Screening and Molecular Docking Approaches

    Directory of Open Access Journals (Sweden)

    P. Srinivasan

    2014-01-01

    Full Text Available Nek6 is a member of the NIMA (never in mitosis, gene A-related serine/threonine kinase family that plays an important role in the initiation of mitotic cell cycle progression. This work is an attempt to emphasize the structural and functional relationship of Nek6 protein based on homology modeling and binding pocket analysis. The three-dimensional structure of Nek6 was constructed by molecular modeling studies and the best model was further assessed by PROCHECK, ProSA, and ERRAT plot in order to analyze the quality and consistency of generated model. The overall quality of computed model showed 87.4% amino acid residues under the favored region. A 3 ns molecular dynamics simulation confirmed that the structure was reliable and stable. Two lead compounds (Binding database ID: 15666, 18602 were retrieved through structure-based virtual screening and induced fit docking approaches as novel Nek6 inhibitors. Hence, we concluded that the potential compounds may act as new leads for Nek6 inhibitors designing.

  17. Virtual anthropology.

    Science.gov (United States)

    Weber, Gerhard W

    2015-02-01

    Comparative morphology, dealing with the diversity of form and shape, and functional morphology, the study of the relationship between the structure and the function of an organism's parts, are both important subdisciplines in biological research. Virtual anthropology (VA) contributes to comparative morphology by taking advantage of technological innovations, and it also offers new opportunities for functional analyses. It exploits digital technologies and pools experts from different domains such as anthropology, primatology, medicine, paleontology, mathematics, statistics, computer science, and engineering. VA as a technical term was coined in the late 1990s from the perspective of anthropologists with the intent of being mostly applied to biological questions concerning recent and fossil hominoids. More generally, however, there are advanced methods to study shape and size or to manipulate data digitally suitable for application to all kinds of primates, mammals, other vertebrates, and invertebrates or to issues regarding plants, tools, or other objects. In this sense, we could also call the field "virtual morphology." The approach yields permanently available virtual copies of specimens and data that comprehensively quantify geometry, including previously neglected anatomical regions. It applies advanced statistical methods, supports the reconstruction of specimens based on reproducible manipulations, and promotes the acquisition of larger samples by data sharing via electronic archives. Finally, it can help identify new, hidden traits, which is particularly important in paleoanthropology, where the scarcity of material demands extracting information from fragmentary remains. This contribution presents a current view of the six main work steps of VA: digitize, expose, compare, reconstruct, materialize, and share. The VA machinery has also been successfully used in biomechanical studies which simulate the stress and strains appearing in structures. Although

  18. Orbital velocity

    OpenAIRE

    Modestino, Giuseppina

    2016-01-01

    The trajectory and the orbital velocity are determined for an object moving in a gravitational system, in terms of fundamental and independent variables. In particular, considering a path on equipotential line, the elliptical orbit is naturally traced, verifying evidently the keplerian laws. The case of the planets of the solar system is presented.

  19. A virtual reality approach to public protection and emergency preparedness planning in dam safety analysis

    Energy Technology Data Exchange (ETDEWEB)

    Assaf, H.; Hartford, D.N.D. [BC Hydro, Burnaby, BC (Canada)

    2002-12-01

    BC Hydro has developed a new approach to analyze and assess the consequences of dam emergencies on human communities. The Life Safety Model (LSM) was designed to enable the electric utility to provide different response agencies with realistic dynamic models of a wide range of emergency scenarios that require a response in the event of a dam failure. LSM is pertinent to public safety because it enables response agencies to develop emergency plans and provides insight into the design of risk mitigation measures through its ability to simulate high risk locations. The model can create representations of downstream communities in potentially impacted areas and can geographically illustrate the potential dam breach events with reference to flood propagation and the movement of people on foot or in vehicles. A wide range of downstream dam operation conditions is presented. LSM merges state of the art technologies and recent scientific advances in environmental simulation and modelling, GIS, artificial intelligence, real time modelling of 2-dimensional dam breach flooding scenarios, structural reliability analysis, and human behaviour characterisation. This paper describes the modular architecture of the model and demonstrates how to generate the vital information needed to characterize a dam failure emergency. 2 refs., 1 tab., 7 figs.

  20. A Consultative Approach to Charter Party Agreements Based on Virtual On Time Arrival

    Directory of Open Access Journals (Sweden)

    Huw Davies

    2017-06-01

    Full Text Available Charter Party agreements underpin the relationship between ship owners and charterers. The agreement guarantees the performance of a vessel in terms of speed and fuel consumption. On this basis the charterers plan the arrival of their cargo and their profit margin. However, ship performance is degraded by age, periods between maintenance and many vessels fail to perform as expected. Moreover the performance is only warranted during the specific conditions stated in the charter party which are not always clear. These usually refer to Beaufort Force (BF and the Douglas Sea and Swell (DSS scale which is archaic in the age of Numerical Weather Prediction. Given these conditions, the stage is set for conflict and there are often disputes over the weather conditions experienced. Moreover ships’ often do not arrive on time because the charterer has assumed that the ship will make good its warranted speed and not taken account of the forecast weather conditions. The authors propose a new way of approaching charter agreements with the emphasis on consultation rather than confrontation facilitated by a new web based software platform.

  1. A statistical approach to virtual cellular experiments: improved causal discovery using accumulation IDA (aIDA).

    Science.gov (United States)

    Taruttis, Franziska; Spang, Rainer; Engelmann, Julia C

    2015-12-01

    We address the following question: Does inhibition of the expression of a gene X in a cellular assay affect the expression of another gene Y? Rather than inhibiting gene X experimentally, we aim at answering this question computationally using as the only input observational gene expression data. Recently, a new statistical algorithm called Intervention calculus when the Directed acyclic graph is Absent (IDA), has been proposed for this problem. For several biological systems, IDA has been shown to outcompete regression-based methods with respect to the number of true positives versus the number of false positives for the top 5000 predicted effects. Further improvements in the performance of IDA have been realized by stability selection, a resampling method wrapped around IDA that enhances the discovery of true causal effects. Nevertheless, the rate of false positive and false negative predictions is still unsatisfactorily high. We introduce a new resampling approach for causal discovery called accumulation IDA (aIDA). We show that aIDA improves the performance of causal discoveries compared to existing variants of IDA on both simulated and real yeast data. The higher reliability of top causal effect predictions achieved by aIDA promises to increase the rate of success of wet lab intervention experiments for functional studies. R code for aIDA is available in the Supplementary material. franziska.taruttis@ur.de, julia.engelmann@ur.de. Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press.

  2. Why do Students use Virtual Social Networks in Iran: a System Approach

    Directory of Open Access Journals (Sweden)

    Babak Saleck Pay

    2013-01-01

    Full Text Available Rise of Social Network Sites, such as Facebook, significantly influences the behaviour of students around the world nowadays. Different studies have been done up till now to investigate different stimuli on using Facebook. In this study, as one of the first attempts to investigate dynamic influencing factors, systems approach is used to consider such factors’ effects and their feedback simultaneously. After finding major factors and estimating the behaviours, in order to verify effects of them, an online questionnaire was prepared to gather Iranian Facebook users’ attitudes toward these factors. After interpreting answers, we ran a dynamic simulation model and made some discussions about the effects of different factors on the time which users spend in Facebook. The results show that negative impact of filtering causes decrease on time users spend in Facebook. Under current situation, although filtering on internet has its effects on users in Iran, tendency toward using different facilities of Facebook is strong enough to overcome these negative effects.

  3. Using Virtual Pets to Increase Fruit and Vegetable Consumption in Children: A Technology-Assisted Social Cognitive Theory Approach.

    Science.gov (United States)

    Ahn, Sun Joo Grace; Johnsen, Kyle; Moore, James; Brown, Scott; Biersmith, Melanie; Ball, Catherine

    2016-02-01

    A virtual pet in the form of a mid-sized dog was developed based on the framework of social cognitive theory and tested as a vehicle for promoting fruit and vegetable (F&V) consumption in children. Three groups of children (N = 68) between the ages of 7 and 13 years were studied: baseline (no treatment), computer only, and virtual dog. Children in the virtual dog condition interacted with the virtual dog for 3 days, setting F&V consumption goals and receiving evaluation and reinforcement based on whether they met their self-set goals. Children vicariously experienced future health outcomes of F&V consumption by seeing, hearing, and feeling their virtual dog's physical and mental health improve or deteriorate based on their F&V consumption in the physical world. Children in the computer only condition interacted with a computer system that presented equivalent features, but without the virtual dog. Children in the baseline condition did not receive any experimental treatment. Results indicated that children in the virtual dog condition chose to be served significantly more F&V than those in the computer only or baseline conditions did. However, children in the virtual dog condition were unable to consume significantly more F&V than those in the computer only condition, although children in those two conditions consumed more F&V than the baseline condition. Food preferences did not differ significantly across the three conditions before and after the experimental treatments. Theoretical and practical potentials of using a virtual pet to promote F&V consumption systematically in children are discussed.

  4. Transverse spectral velocity estimation.

    Science.gov (United States)

    Jensen, Jørgen

    2014-11-01

    A transverse oscillation (TO)-based method for calculating the velocity spectrum for fully transverse flow is described. Current methods yield the mean velocity at one position, whereas the new method reveals the transverse velocity spectrum as a function of time at one spatial location. A convex array probe is used along with two different estimators based on the correlation of the received signal. They can estimate the velocity spectrum as a function of time as for ordinary spectrograms, but they also work at a beam-to-flow angle of 90°. The approach is validated using simulations of pulsatile flow using the Womersly-Evans flow model. The relative bias of the mean estimated frequency is 13.6% and the mean relative standard deviation is 14.3% at 90°, where a traditional estimator yields zero velocity. Measurements have been conducted with an experimental scanner and a convex array transducer. A pump generated artificial femoral and carotid artery flow in the phantom. The estimated spectra degrade when the angle is different from 90°, but are usable down to 60° to 70°. Below this angle the traditional spectrum is best and should be used. The conventional approach can automatically be corrected for angles from 0° to 70° to give fully quantitative velocity spectra without operator intervention.

  5. VO-ESD: a virtual observatory approach to describe the geomagnetic field temporal variations with application to Swarm data

    Science.gov (United States)

    Saturnino, Diana; Langlais, Benoit; Amit, Hagay; Mandea, Mioara; Civet, François; Beucler, Éric

    2017-04-01

    A complete description of the main geomagnetic field temporal variation is crucial to understand dynamics in the core. This variation, termed secular variation (SV), is known with high accuracy at ground magnetic observatory locations. However the description of its spatial variability is hampered by the globally uneven distribution of the observatories. For the past two decades a global coverage of the field changes has been allowed by satellites. Their surveys of the geomagnetic field have been used to derive and improve global spherical harmonic (SH) models through some strict data selection schemes to minimise external field contributions. But discrepancies remain between ground measurements and field predictions by these models. Indeed, the global models do not reproduce small spatial scales of the field temporal variations. To overcome this problem we propose a modified Virtual Observatory (VO) approach by defining a globally homogeneous mesh of VOs at satellite altitude. With this approach we directly extract time series of the field and its temporal variation from satellite measurements as it is done at observatory locations. As satellite measurements are acquired at different altitudes a correction for the altitude is needed. Therefore, we apply an Equivalent Source Dipole (ESD) technique for each VO and each given time interval to reduce all measurements to a unique location, leading to time series similar to those available at ground magnetic observatories. Synthetic data is first used to validate the new VO-ESD approach. Then, we apply our scheme to measurements from the Swarm mission. For the first time, a 2.5 degrees resolution global mesh of VO times series is built. The VO-ESD derived time series are locally compared to ground observations as well as to satellite-based model predictions. The approach is able to describe detailed temporal variations of the field at local scales. The VO-ESD time series are also used to derive global SH models. Without

  6. The French initiative for scientific cores virtual curating : a user-oriented integrated approach

    Science.gov (United States)

    Pignol, Cécile; Godinho, Elodie; Galabertier, Bruno; Caillo, Arnaud; Bernardet, Karim; Augustin, Laurent; Crouzet, Christian; Billy, Isabelle; Teste, Gregory; Moreno, Eva; Tosello, Vanessa; Crosta, Xavier; Chappellaz, Jérome; Calzas, Michel; Rousseau, Denis-Didier; Arnaud, Fabien

    2016-04-01

    ) and displayed in international portals (currently, NOAA's IMLGS). In this paper, we present the architecture of the integrated system, future perspectives and the approach we adopted to reach our goals. We will also present in front of our poster, one of the three mobile applications, dedicated more particularly to the operations of continental drillings.

  7. An alternative approach to the Army Physical Fitness Test two-mile run using critical velocity and isoperformance curves.

    Science.gov (United States)

    Fukuda, David H; Smith, Abbie E; Kendall, Kristina L; Cramer, Joel T; Stout, Jeffrey R

    2012-02-01

    The purpose of this study was to evaluate the use of critical velocity (CV) and isoperformance curves as an alternative to the Army Physical Fitness Test (APFT) two-mile running test. Seventy-eight men and women (mean +/- SE; age: 22.1 +/- 0.34 years; VO2(MAX): 46.1 +/- 0.82 mL/kg/min) volunteered to participate in this study. A VO2(MAX) test and four treadmill running bouts to exhaustion at varying intensities were completed. The relationship between total distance and time-to-exhaustion was tracked for each exhaustive run to determine CV and anaerobic running capacity. A VO2(MAX) prediction equation (Coefficient of determination: 0.805; Standard error of the estimate: 3.2377 mL/kg/min) was developed using these variables. Isoperformance curves were constructed for men and women to correspond with two-mile run times from APFT standards. Individual CV and anaerobic running capacity values were plotted and compared to isoperformance curves for APFT 2-mile run scores. Fifty-four individuals were determined to receive passing scores from this assessment. Physiological profiles identified from this procedure can be used to assess specific aerobic or anaerobic training needs. With the use of time-to-exhaustion as opposed to a time-trial format used in the two-mile run test, pacing strategies may be limited. The combination of variables from the CV test and isoperformance curves provides an alternative to standardized time-trial testing.

  8. Ideas and Approaches on “Construction of High Level Simulation Experimental Teaching Center of Virtual Chemical Laboratory”

    Science.gov (United States)

    Zhang, Yunshen

    2017-11-01

    With the spiritual guidance of the Circular on the Construction of National Virtual Simulation Experimental Teaching Center by the National Department of Education, according to the requirements of construction task and work content, and based on the reality of the simulation experimental teaching center of virtual chemical laboratory at Tianjin University, this paper mainly strengthens the understanding of virtual simulation experimental teaching center from three aspects, and on this basis, this article puts forward specific construction ideas, which refer to the “four combinations, five in one, the optimization of the resources and school-enterprise cooperation”, and on this basis, this article has made effective explorations. It also shows the powerful functions of the virtual simulation experimental teaching platform in all aspects by taking the synthesis and analysis of organic compounds as an example.

  9. 3D position and velocity vector computations of objects jettisoned from the international space station using close-range photogrammetry approach

    Science.gov (United States)

    Papanyan, Valeri; Oshel, Edward; Adamo, Daniel

    2008-04-01

    Measurement of the jettisoned object departure trajectory and velocity vector in the International Space Station (ISS) reference frame is vitally important for prompt evaluation of the object's imminent orbit. We report on the first successful application of photogrammetric analysis of the ISS imagery for the prompt computation of the jettisoned object's position and velocity vectors. As post-EVA analyses examples, we present the Floating Potential Probe (FPP) and the Russian "Orlan" Space Suit jettisons, as well as the near-real-time (provided in several hours after the separation) computations of the Video Stanchion Support Assembly Flight Support Assembly (VSSA-FSA) and Early Ammonia Servicer (EAS) jettisons during the US astronauts space-walk. Standard close-range photogrammetry analysis was used during this EVA to analyze two on-board camera image sequences down-linked from the ISS. In this approach the ISS camera orientations were computed from known coordinates of several reference points on the ISS hardware. Then the position of the jettisoned object for each time-frame was computed from its image in each frame of the video-clips. In another, "quick-look" approach used in near-real time, orientation of the cameras was computed from their position (from the ISS CAD model) and operational data (pan and tilt) then location of the jettisoned object was calculated only for several frames of the two synchronized movies.

  10. 3D Position and Velocity Vector Computations of Objects Jettisoned from the International Space Station Using Close-Range Photogrammetry Approach

    Science.gov (United States)

    Papanyan, Valeri; Oshle, Edward; Adamo, Daniel

    2008-01-01

    Measurement of the jettisoned object departure trajectory and velocity vector in the International Space Station (ISS) reference frame is vitally important for prompt evaluation of the object s imminent orbit. We report on the first successful application of photogrammetric analysis of the ISS imagery for the prompt computation of the jettisoned object s position and velocity vectors. As post-EVA analyses examples, we present the Floating Potential Probe (FPP) and the Russian "Orlan" Space Suit jettisons, as well as the near-real-time (provided in several hours after the separation) computations of the Video Stanchion Support Assembly Flight Support Assembly (VSSA-FSA) and Early Ammonia Servicer (EAS) jettisons during the US astronauts space-walk. Standard close-range photogrammetry analysis was used during this EVA to analyze two on-board camera image sequences down-linked from the ISS. In this approach the ISS camera orientations were computed from known coordinates of several reference points on the ISS hardware. Then the position of the jettisoned object for each time-frame was computed from its image in each frame of the video-clips. In another, "quick-look" approach used in near-real time, orientation of the cameras was computed from their position (from the ISS CAD model) and operational data (pan and tilt) then location of the jettisoned object was calculated only for several frames of the two synchronized movies. Keywords: Photogrammetry, International Space Station, jettisons, image analysis.

  11. Virtual reality rehabilitation as a treatment approach for older women with mixed urinary incontinence: a feasibility study.

    Science.gov (United States)

    Elliott, Valérie; de Bruin, Eling D; Dumoulin, Chantale

    2015-03-01

    Motivated patients are more likely to adhere to treatment resulting in better outcomes. Virtual reality rehabilitation (VRR) is a treatment approach that includes video gaming to enhance motivation and functional training. The study objectives were (1) to evaluate the feasibility of using a combination of pelvic floor muscles (PFM) exercises and VRR (PFM/VRR) to treat mixed urinary incontinence (MUI) in older women, (2) to evaluate the effectiveness of the PFM/VRR program on MUI symptoms, quality of life (QoL), and (3) gather quantitative information regarding patient satisfaction with this new combined training program. Women 65 years and older with at least 2 weekly episodes of MUI were recruited. Participants were evaluated two times before and one time after a 12-week PFM/VRR training program. Feasibility was defined as the participants' rate of participation in and completion of both the PFM/VRR training program and the home exercise. Effectiveness was evaluated through a bladder diary, pad test, symptom and QoL questionnaire, and participant's satisfaction through a questionnaire. Twenty-four women (70.5 ± 3.6 years) participated. The participants complied with the study demands in terms of attendance at the weekly treatment sessions (91%), adherence to home exercise (92%) and completion of the three evaluations (96%). Post-intervention, the frequency and quantity of urine leakage decreased and patient-reported symptoms and QoL improved significantly. Most participants were very satisfied with treatment (91%). A combined PFM/VRR program is an acceptable, efficient, and satisfying functional treatment for older women with MUI and should be explore through further RCTs. © 2014 Wiley Periodicals, Inc.

  12. Rational Design of Small-Molecule Stabilizers of Spermine Synthase Dimer by Virtual Screening and Free Energy-Based Approach

    Science.gov (United States)

    Zhang, Zhe; Martiny, Virginie; Lagorce, David; Ikeguchi, Yoshihiko; Alexov, Emil; Miteva, Maria A.

    2014-01-01

    Snyder-Robinson Syndrome (SRS) is a rare mental retardation disorder which is caused by the malfunctioning of an enzyme, the spermine synthase (SMS), which functions as a homo-dimer. The malfunctioning of SMS in SRS patients is associated with several identified missense mutations that occur away from the active site. This investigation deals with a particular SRS-causing mutation, the G56S mutation, which was shown computationally and experimentally to destabilize the SMS homo-dimer and thus to abolish SMS enzymatic activity. As a proof-of-concept, we explore the possibility to restore the enzymatic activity of the malfunctioning SMS mutant G56S by stabilizing the dimer through small molecule binding at the mutant homo-dimer interface. For this purpose, we designed an in silico protocol that couples virtual screening and a free binding energy-based approach to identify potential small-molecule binders on the destabilized G56S dimer, with the goal to stabilize it and thus to increase SMS G56S mutant activity. The protocol resulted in extensive list of plausible stabilizers, among which we selected and tested 51 compounds experimentally for their capability to increase SMS G56S mutant enzymatic activity. In silico analysis of the experimentally identified stabilizers suggested five distinctive chemical scaffolds. This investigation suggests that druggable pockets exist in the vicinity of the mutation sites at protein-protein interfaces which can be used to alter the disease-causing effects by small molecule binding. The identified chemical scaffolds are drug-like and can serve as original starting points for development of lead molecules to further rescue the disease-causing effects of the Snyder-Robinson syndrome for which no efficient treatment exists up to now. PMID:25340632

  13. A new approach for the calculation of falling droplets from a cylindrical glass capillary based on force balance and velocity

    Science.gov (United States)

    Hummel, Sebastian; Bogner, Martin; Haub, Michael; Saegebarth, Joachim; Sandmaier, Hermann

    2017-11-01

    This paper presents a new simple analytical method to estimate the properties of falling droplets without solving complex differential equations. The derivation starts from the balance of forces and uses Newton’s second law and the equations of motion to calculate the volume of growing and detaching droplets and the time between two successive droplets falling out of a thin cylindrical capillary of borosilicate glass. In this specific case the reservoir is located above the capillary and the hydrostatic pressure of the fluid level leads to drop formation times about one second. In the second part of this paper experimental results are presented to validate the introduced calculation method. It is shown that the new approach describes the measuring results within a deviation of ±6.2%. The third part of the paper sums up the advantages of the new approach and an outlook is given on how the research on this topic will be continued.

  14. Control of grid integrated voltage source converters under unbalanced conditions: development of an on-line frequency-adaptive virtual flux-based approach

    Energy Technology Data Exchange (ETDEWEB)

    Suul, Jon Are

    2012-03-15

    Three-Phase Voltage Source Converters (VSCs) are finding widespread applications in grid integrated power conversion systems. The control systems of such VSCs are in an increasing number of these applications required to operate during voltage disturbances and unbalanced conditions. Control systems designed for grid side voltagesensor-less operation are at the same time becoming attractive due to the continuous drive for cost reduction and increased reliability of VSCs, but are not commonly applied for operation during unbalanced conditions. Methods for voltage-sensor-less grid synchronization and control of VSCs under unbalanced grid voltage conditions will therefore be the main focus of this Thesis. Estimation methods based on the concept of Virtual Flux, considering the integral of the converter voltage in analogy to the flux of an electric machine, are among the simplest and most well known techniques for achieving voltage-sensor-less grid synchronization. Most of the established techniques for Virtual Flux estimation are, however, either sensitive to grid frequency variations or they are not easily adaptable for operation under unbalanced grid voltage conditions. This Thesis addresses both these issues by proposing a simple approach for Virtual Flux estimation by utilizing a frequency-adaptive filter based on a Second Order Generalized Integrator (SOGI). The proposed approach can be used to achieve on-line frequency-adaptive varieties of conventional strategies for Virtual Flux estimation. The main advantage is, however, that the SOGI-based Virtual Flux estimation can be arranged in a structure that achieves inherent symmetrical component sequence separation under unbalanced conditions. The proposed method for Virtual Flux estimation can be used as a general basis for voltage-sensor-less grid synchronization and control during unbalanced conditions. In this Thesis, the estimated Virtual Flux signals are used to develop a flexible strategy for control of active

  15. Virtual endoscopy of the middle ear: experimental and clinical results of a standardised approach using multi-slice helical computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Rodt, Thomas; Bartling, Soenke; Schmidt, Anja M.; Becker, Hartmut [Department of Neuroradiology, Medical School Hannover (Germany); Weber, Benno P.; Lenarz, Thomas [Department of Otorhinolaryngology, Medical School Hannover (Germany)

    2002-07-01

    Virtual endoscopy (VE) enables non-invasive 3D endoluminal imaging of the middle ear by post-processing of CT data. To optimise the clinical application a standardised approach was evaluated in normal and pathologic cases. Data acquisition was performed using multi-slice helical CT in 20 normal patients and 15 patients with malformation or trauma. Virtual endoscopy of the tympanic cavity and 3D images of the ossicles were generated using surface and volume rendering. Qualitative assessment of the representation of anatomical structures was performed in normal patients. In 15 pathological cases the diagnostic benefit was evaluated by comparing the 3D images to the 2D images and intra-operative findings. In all 35 cases 3D imaging was possible using the standardised approach. The ossicular chain as well as the bony and soft tissue structures of the tympanic cavity were visualised in 20 normal patients. In 7 of 8 patients with malformation and 1 of 7 patients with trauma the original diagnosis was changed by 3D imaging. Standardisation and evaluation of the method in normal patients is essential as it enhances the diagnostic reliability. Virtual endoscopy facilitates understanding of the complex anatomy of the middle ear. In cases of suspected malformation and confirmed trauma it is helpful for diagnosis and surgical planning. (orig.)

  16. Virtual screening approach to identifying influenza virus neuraminidase inhibitors using molecular docking combined with machine-learning-based scoring function.

    Science.gov (United States)

    Zhang, Li; Ai, Hai-Xin; Li, Shi-Meng; Qi, Meng-Yuan; Zhao, Jian; Zhao, Qi; Liu, Hong-Sheng

    2017-10-10

    In recent years, an epidemic of the highly pathogenic avian influenza H7N9 virus has persisted in China, with a high mortality rate. To develop novel anti-influenza therapies, we have constructed a machine-learning-based scoring function (RF-NA-Score) for the effective virtual screening of lead compounds targeting the viral neuraminidase (NA) protein. RF-NA-Score is more accurate than RF-Score, with a root-mean-square error of 1.46, Pearson's correlation coefficient of 0.707, and Spearman's rank correlation coefficient of 0.707 in a 5-fold cross-validation study. The performance of RF-NA-Score in a docking-based virtual screening of NA inhibitors was evaluated with a dataset containing 281 NA inhibitors and 322 noninhibitors. Compared with other docking-rescoring virtual screening strategies, rescoring with RF-NA-Score significantly improved the efficiency of virtual screening, and a strategy that averaged the scores given by RF-NA-Score, based on the binding conformations predicted with AutoDock, AutoDock Vina, and LeDock, was shown to be the best strategy. This strategy was then applied to the virtual screening of NA inhibitors in the SPECS database. The 100 selected compounds were tested in an in vitro H7N9 NA inhibition assay, and two compounds with novel scaffolds showed moderate inhibitory activities. These results indicate that RF-NA-Score improves the efficiency of virtual screening for NA inhibitors, and can be used successfully to identify new NA inhibitor scaffolds. Scoring functions specific for other drug targets could also be established with the same method.

  17. Machine Learning Approaches Toward Building Predictive Models for Small Molecule Modulators of miRNA and Its Utility in Virtual Screening of Molecular Databases.

    Science.gov (United States)

    Periwal, Vinita; Scaria, Vinod

    2017-01-01

    The ubiquitous role of microRNAs (miRNAs) in a number of pathological processes has suggested that they could act as potential drug targets. RNA-binding small molecules offer an attractive means for modulating miRNA function. The availability of bioassay data sets for a variety of biological assays and molecules in public domain provides a new opportunity toward utilizing them to create models and further utilize them for in silico virtual screening approaches to prioritize or assign potential functions for small molecules. Here, we describe a computational strategy based on machine learning for creation of predictive models from high-throughput biological screens for virtual screening of small molecules with the potential to inhibit microRNAs. Such models could be potentially used for computational prioritization of small molecules before performing high-throughput biological assay.

  18. Virtual box

    DEFF Research Database (Denmark)

    Stougaard, Malthe Kirkhoff

    2007-01-01

    . This paper reports on the design, implementation and initial evaluation of Virtual Box. Virtual Box attempts to create a physical and engaging context in order to support reciprocal interactions with expressive content. An implemented version of Virtual Box is evaluated in a location-aware environment...

  19. Enhancing a Low-Cost Virtual Reality Application through Constructivist Approach: The Case of Spatial Training of Middle Graders

    Science.gov (United States)

    Samsudin, Khairulanuar; Rafi, Ahmad; Mohamad Ali, Ahmad Zamzuri; Abd. Rashid, Nazre

    2014-01-01

    The aim of this study is to develop and to test a low-cost virtual reality spatial trainer in terms of its effectiveness in spatial training. The researchers adopted three features deriving from the constructivist perspective to guide the design of the trainer, namely interaction, instruction, and support. The no control pre test post test…

  20. Students' Personal Networks in Virtual and Personal Learning Environments: A Case Study in Higher Education Using Learning Analytics Approach

    Science.gov (United States)

    Casquero, Oskar; Ovelar, Ramón; Romo, Jesús; Benito, Manuel; Alberdi, Mikel

    2016-01-01

    The main objective of this paper is to analyse the effect of the affordances of a virtual learning environment and a personal learning environment (PLE) in the configuration of the students' personal networks in a higher education context. The results are discussed in light of the adaptation of the students to the learning network made up by two…

  1. Virtual screening of virtual libraries.

    Science.gov (United States)

    Green, Darren V S

    2003-01-01

    Virtual screening of virtual libraries (VSVL) is a rapidly changing area of research. Great efforts are being made to produce better algorithms, selection methods and infrastructure. Yet, the number of successful examples in the literature is not impressive, although the quality of work certainly is high. Why is this? One reason is that these methods tend to be applied at the lead generation stage and therefore there is a large lead-time before successful examples appear in the literature. However, any computational chemist would confirm that these methods are successful and there exists a glut of start-up companies specialising in virtual screening. Moreover, the scientific community would not be focussing so much attention on this area if it were not yielding results. Even so, the paucity of literature data is certainly a hindrance to the development of better methods. The VSVL process is unique within the discovery process, in that it is the only method that can screen the > 10(30) genuinely novel molecules out there. Already, some VSVL methods are evaluating 10(13) compounds, a capacity that high throughput screening can only dream of. There is a huge potential advantage for the company that develops efficient and effective methods, for lead generation, lead hopping and optimization of both potency and ADME properties. To do this, it requires more than the software, it requires confidence to exploit the methodology, to commit synthesis on the basis of it, and to build this approach into the medicinal chemistry strategy. It is a fact that these tools remain quite daunting for the majority of scientists working at the bench. The routine use of these methods is not simply a matter of education and training. Integration of these methods into accessible and robust end user software, without dilution of the science, must be a priority. We have reached a coincidence, where several technologies have the required level of maturity predictive computational chemistry

  2. Virtual Instrumentation and Virtual Environments

    NARCIS (Netherlands)

    Spoelder, H.J.W.

    1999-01-01

    Instrumentation, interaction and virtual environments provide a challenging triplet for the next generation of instrumentation and measurement tools. As such, they are the logical continuation of an increasingly important component within (virtual) instrumentation. Despite these changes, however,

  3. Wireless virtualization

    CERN Document Server

    Wen, Heming; Le-Ngoc, Tho

    2013-01-01

    This SpringerBriefs is an overview of the emerging field of wireless access and mobile network virtualization. It provides a clear and relevant picture of the current virtualization trends in wireless technologies by summarizing and comparing different architectures, techniques and technologies applicable to a future virtualized wireless network infrastructure. The readers are exposed to a short walkthrough of the future Internet initiative and network virtualization technologies in order to understand the potential role of wireless virtualization in the broader context of next-generation ubiq

  4. Virtual marketing in virtual enterprises

    OpenAIRE

    Ale Ebrahim, Nader; Fattahi, Hamaid Ali; Golnam, Arash

    2008-01-01

    Virtualization caused tremendous evolution in the economics of marketing channels, patterns of physical distribution and the structure of distributors and developed a new concept that is known as virtual marketing (VM). VM combines the powerful technologies of interactive marketing and virtual reality. Virtual enterprise (VE) refers to an organization not having a clear physical locus. In other words, VE is an organization distributed geographically and whose work is coordinated through e...

  5. Navigation strategy training using virtual reality in six chronic stroke patients: A novel and explorative approach to the rehabilitation of navigation impairment.

    Science.gov (United States)

    Claessen, Michiel H G; van der Ham, Ineke J M; Jagersma, Elbrich; Visser-Meily, Johanna M A

    2016-10-01

    Recent studies have shown that navigation impairment is a common complaint after brain injury. Effective training programmes aiming to improve navigation ability in neurological patients are, however, scarce. The few reported programmes are merely focused on recalling specific routes rather than encouraging brain-damaged patients to use an alternative navigation strategy, applicable to any route. Our aim was therefore to investigate the feasibility of a (virtual reality) navigation training as a tool to instruct chronic stroke patients to adopt an alternative navigation strategy. Navigation ability was systematically assessed before the training. The training approach was then determined based on the individual pattern of navigation deficits of each patient. The use of virtual reality in the navigation strategy training in six middle-aged stroke patients was found to be highly feasible. Furthermore, five patients learned to (partially) apply an alternative navigation strategy in the virtual environment, suggesting that navigation strategies are mouldable rather than static. In the evaluation of their training experiences, the patients judged the training as valuable and proposed some suggestions for further improvement. The notion that the navigation strategy people use can be influenced after a short training procedure is a novel finding and initiates a direction for future studies.

  6. A virtual high-throughput screening approach to the discovery of novel inhibitors of the bacterial leucine transporter, LeuT

    DEFF Research Database (Denmark)

    Simmons, Katie J; Gotfryd, Kamil; Billesbølle, Christian B

    2013-01-01

    to the elucidation of over 250 unique membrane protein crystal structures. The aim of the European Drug Initiative for Channels and Transporter (EDICT) project is to use the structures of clinically significant membrane proteins for the development of lead molecules. One of the approaches used to achieve...... this is a virtual high-throughput screening (vHTS) technique initially developed for soluble proteins. This paper describes application of this technique to the discovery of inhibitors of the leucine transporter (LeuT), a member of the neurotransmitter:sodium symporter (NSS) family....

  7. A Statistical Approach to Continuous Self-Calibrating Eye Gaze Tracking for Head-Mounted Virtual Reality Systems

    OpenAIRE

    Tripathi, Subarna; Guenter, Brian

    2016-01-01

    We present a novel, automatic eye gaze tracking scheme inspired by smooth pursuit eye motion while playing mobile games or watching virtual reality contents. Our algorithm continuously calibrates an eye tracking system for a head mounted display. This eliminates the need for an explicit calibration step and automatically compensates for small movements of the headset with respect to the head. The algorithm finds correspondences between corneal motion and screen space motion, and uses these to...

  8. Transverse Spectral Velocity Estimation

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt

    2014-01-01

    array probe is used along with two different estimators based on the correlation of the received signal. They can estimate the velocity spectrum as a function of time as for ordinary spectrograms, but they also work at a beam-to-flow angle of 90°. The approach is validated using simulations of pulsatile...... flow using the Womersly–Evans flow model. The relative bias of the mean estimated frequency is 13.6% and the mean relative standard deviation is 14.3% at 90°, where a traditional estimator yields zero velocity. Measurements have been conducted with an experimental scanner and a convex array transducer....... A pump generated artificial femoral and carotid artery flow in the phantom. The estimated spectra degrade when the angle is different from 90°, but are usable down to 60° to 70°. Below this angle the traditional spectrum is best and should be used. The conventional approach can automatically be corrected...

  9. Exploration of the structural requirements of HIV-protease inhibitors using pharmacophore, virtual screening and molecular docking approaches for lead identification.

    Science.gov (United States)

    Islam, Md Ataul; Pillay, Tahir S

    2015-03-01

    Pharmacoinformatics approaches are widely used in the field of drug discovery as it saves time, investment and animal sacrifice. In the present study, pharmacore-based virtual screening was adopted to identify potential HIV-protease ligands as anti-HIV agents. Pharmacophore is the 3D orientation and spatial arrangement of functional groups that are critical for binding at the active site cavity. Virtual screening retrieves potential hit molecules from databases based on imposed criteria. A set of 30 compounds were selected with inhibition constant as training set from 129 compounds of dataset set and subsequently the pharmacophore model was developed. The selected best model consists of hydrogen bond acceptor and donor, hydrophobic and aromatic ring, features critical for HIV-protease inhibitors. The model exhibits high correlation (R=0.933), less rmsd (1.014), high cross validated correlation coefficient (Q(2)=0.872) among the ten models examined and validated by Fischer's randomization test at 95% confidence level. The acceptable parameters of test set prediction, such as R(pred)(2)=0.768 and r(m(test))(2)=0.711 suggested that external predictivity of the model was significant. The pharmacophore model was used to perform a virtual screening employing the NCI database. Initial hits were sorted using a number of parameters and finally seven compounds were proposed as potential HIV-protease molecules. One potential HIV-protease ligand is reportedly confirmed as an active agent for anti-HIV screening, validating the current approach. It can be postulated that the pharmacophore model facilitates the selection of novel scaffold of HIV-protease inhibitors and can also allow the design of new chemical entities. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Virtual Congresses

    Science.gov (United States)

    Lecueder, Silvia; Manyari, Dante E.

    2000-01-01

    A new form of scientific medical meeting has emerged in the last few years—the virtual congress. This article describes the general role of computer technologies and the Internet in the development of this new means of scientific communication, by reviewing the history of “cyber sessions” in medical education and the rationale, methods, and initial results of the First Virtual Congress of Cardiology. Instructions on how to participate in this virtual congress, either actively or as an observer, are included. Current advantages and disadvantages of virtual congresses, their impact on the scientific community at large, and future developments and possibilities in this area are discussed. PMID:10641960

  11. Virtual Laboratories and Virtual Worlds

    Science.gov (United States)

    Hut, Piet

    2008-05-01

    Since we cannot put stars in a laboratory, astrophysicists had to wait till the invention of computers before becoming laboratory scientists. For half a century now, we have been conducting experiments in our virtual laboratories. However, we ourselves have remained behind the keyboard, with the screen of the monitor separating us from the world we are simulating. Recently, 3D on-line technology, developed first for games but now deployed in virtual worlds like Second Life, is beginning to make it possible for astrophysicists to enter their virtual labs themselves, in virtual form as avatars. This has several advantages, from new possibilities to explore the results of the simulations to a shared presence in a virtual lab with remote collaborators on different continents. I will report my experiences with the use of Qwaq Forums, a virtual world developed by a new company (see http://www.qwaq.com).

  12. Reliable estimation of virtual source position for SAFT imaging.

    Science.gov (United States)

    Chang, Chih-Hsiung; Chang, Young-Fo; Ma, Yushieh; Shung, K K

    2013-02-01

    The synthetic aperture focusing technique (SAFT), employing a scanned focused transducer as a virtual source, is commonly used to image flaws in immersion testing. The position of a virtual source is estimated from rays emitted from the rim of a focused transducer. However, it is often found that the virtual source position cannot be uniquely determined because of severe focal spot aberration at the focal zone. Based on an analysis of the energy radiated from the focused transducer and the refracted energy varied with the incident angle of ultrasound, we propose that paraxial rays emitted from the focused transducer are the best for estimating the position of a virtual source for incorporation into SAFT. This study results also shows that by using this simple virtual source position estimation for SAFT, the axial resolution and SNR of the reconstructed image can be greatly improved. This new approach minimizes the effect of such factors as refraction at high-velocity-contrast interfaces, distance of the transducer to the couplant-specimen interface, and the focal length of a focused transducer, which may cause focal spot aberration resulting in decreased sensitivity in SAFT imaging.

  13. Virtual Acoustics

    Science.gov (United States)

    Lokki, Tapio; Savioja, Lauri

    The term virtual acoustics is often applied when sound signal is processed to contain features of a simulated acoustical space and sound is spatially reproduced either with binaural or with multichannel techniques. Therefore, virtual acoustics consists of spatial sound reproduction and room acoustics modeling.

  14. Virtual projects

    DEFF Research Database (Denmark)

    Svejvig, Per; Commisso, Trine Hald

    2012-01-01

    Virtual projects are common with global competition, market development, and not least the financial crisis forcing organizations to reduce their costs drastically. Organizations therefore have to place high importance on ways to carry out virtual projects and consider appropriate practices...... for performing these projects. This paper compares best practices with practiced practices for virtual projects and discusses ways to bridge the gap between them. We have studied eleven virtual projects in five Danish organizations and compared them with a predefined list of best practices compiled from...... that the best practice knowledge has not permeated sufficiently to the practice. Furthermore, the appropriate application of information and communication technology (ICT) remains a big challenge, and finally project managers are not sufficiently trained in organizing and conducting virtual projects...

  15. Virtual Exploratories

    DEFF Research Database (Denmark)

    Jensen, Sisse Siggaard

    2006-01-01

    This paper proposes the notion of activity-systems to denote a virtual frame of activity that requires mutually coordinated action. The underlying assumption is that such framings may support the informal learning and reflective practices of actors, and especially so, when they are provoking...... and challenging. It is suggested that the prevailing ‘traditions’ of collaborative learning and knowledge sharing need to be challenged and complemented, if we are to be able to support the variety and the diversity in the repertoires of virtual learning activities. In order to conceptualize such activity......-systems, the paper introduces the designing strategy referred to as virtual exploratories. Some of the advanced virtual worlds may inspire the design of such provoking and challenging virtual exploratories, and especially the Massively Multi-User Online Role-Playing Games (MMORPGS). However, if we have to learn from...

  16. Realistic Visualization of Virtual Views and Virtual Cinema

    DEFF Research Database (Denmark)

    Livatino, Salvatore

    2005-01-01

    Realistic Virtual View Visualization is a new field of research which has received increasing attention in recent years. It is strictly related to the increased popularity of virtual reality and the spread of its applications, among which virtual photography and cinematography. The use of computer...... generated characters, "virtual actors", in the motion picture production increases every day. While the most known computer graphics techniques have largely been adopted successfully in nowadays fictions, it still remains very challenging to implement virtual actors which would resemble, visually, human...... beings. Interestingly, film directors have been looking at the recent progress achieved by the research community in the field of realistic visualization of virtual views, and they have successfully implemented state of the art research approaches in their productions. An innovative concept...

  17. Preliminary Investigation of Self-Reported Emotional Responses to Approaching and Receding Footstep Sounds in a Virtual Reality Context

    DEFF Research Database (Denmark)

    Sikström, Erik; Nilsson, Niels Christian; Nordahl, Rolf

    2013-01-01

    The emotional impact of approaching and receding sounds sources studies has previously been studied in seated laboratory experiments in with and without accompanying visual stimulus. This paper investigates the emotional responses to approaching and receding footstep sounds in an interactive...

  18. A Virtual Tour of Virtual Schools.

    Science.gov (United States)

    Joiner, Lottie L.

    2002-01-01

    Briefly describes the eight virtual schools in the United States: Kentucky Virtual High School; Illinois Virtual High School; Florida Virtual School; CCS Web Academy in Fayetteville, North Carolina; The Virtual High School in Hudson, Massachusetts; Basehor-Linwood Virtual Charter School in Kansas; Monte Vista Online Academy in Colorado; and…

  19. Virtual screening and repositioning of inconclusive molecules of beta-lactamase Bioassays-A data mining approach.

    Science.gov (United States)

    Gad, Akshata; Manuel, Andrew Titus; K R, Jinuraj; John, Lijo; R, Sajeev; V G, Shanmuga Priya; U C, Abdul Jaleel

    2017-10-01

    This study focuses on the best possible way forward in utilizing inconclusive molecules of PubChem bioassays AID 1332, AID 434987 and AID 434955, which are related to beta-lactamase inhibitors of Mycobacterium tuberculosis (Mtb). The inadequacy in the experimental methods that were observed during the invitro screening resulted in an inconclusive dataset. This could be due to certain moieties present within the molecules. In order to reconsider such molecules, insilico methods can be suggested in place of invitro methods For instance, datamining and medicinal chemistry methods: have been adopted to prioritise the inconclusive dataset into active or inactive molecules. These include the Random Forest algorithm for dataminning, Lilly MedChem rules for virtually screening out the promiscuity, and Self Organizing Maps (SOM) for clustering the active molecules and enlisting them for repositioning through the use of artificial neural networks. These repositioned molecules could then be prioritized for downstream drug discovery analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Inhibitors of the Cdc34 acidic loop: A computational investigation integrating molecular dynamics, virtual screening and docking approaches

    Directory of Open Access Journals (Sweden)

    Alberto Arrigoni

    2014-01-01

    Here, we carried out a computational study based on molecular dynamics, virtual screening and docking to identify potential inhibitory compounds of Cdc34, modulating the acidic loop conformation. The molecules identified in this study have been designed to act as molecular hinges that can bind the acidic loop in its closed conformation, thus inhibiting the Cdc34-mediated ubiquitination cascade at the ubiquitin-charging step. In particular, we proposed a pharmacophore model featuring two amino groups in the central part of the model and two lateral aromatic chains, which respectively establish electrostatic interactions with the acidic loop (Asp 108 and Glu 109 and a hydrogen bond with Ser 139, which is one of the key residues for Cdc34 activity.

  1. Kinematic Skeleton Based Control of a Virtual Simulator for Military Training

    Directory of Open Access Journals (Sweden)

    Soyeon Lee

    2015-06-01

    Full Text Available Virtual simulation technology has been considered as a highly efficient and cost-effective solution for a soldier training system, and evolved into diverse combinations of hardware and software. To maximize the virtual reality effect within a restricted space, a locomotion interface such as an omni-directional treadmill is introduced as a major component of a virtual simulator, therefore real time interaction between human and the virtual simulator becomes very important. Displacement and heading changes of the trainee are crucial information to control the virtual simulator when we implement highly reactive motion control for the omni-directional treadmill and interaction control of the virtual contents. This paper proposes a control parameter estimation algorithm for the virtual training simulator by using two types of motion capture sensors and presents the experimental results. Kinematic joint positions are analyzed to estimate the trainee’s location and velocity for feedback and feedforward control of the omni-directional treadmill. The accuracy of two approaches is evaluated by comparing with the reference system, which gives a ground truth value.

  2. Virtual Reality

    Directory of Open Access Journals (Sweden)

    Dan L. Lacrãmã

    2007-01-01

    Full Text Available This paper is focused on the presentation of Virtual Reality principles together with the main implementation methods and techniques. An overview of the main development directions is included.

  3. Virtual Savannah

    DEFF Research Database (Denmark)

    Eskildsen, Søren; Rodil, Kasper; Rehm, Matthias

    2012-01-01

    It is a daunting task to visualize square kilometers of African savannah and currently in zoos it is impossible to present true African ecology to visitors. Virtual Savannah is a dynamic virtual world that introduces school children to a 3D representation of the wildlife sanctuaries Serengeti...... and Masai Mara. The objective is to substitute supplementary textual information currently used in schools and provide the teacher with information about each pupil. The Virtual Savannah was tested in situ on 19 pupils age 10-11 with the purpose of logging all interaction with animals, GUI...... and the navigation. The test depicted how they managed to search the virtual world for answers in patterns related to restrictions in the system and using graphical points of interest as reference points. Collecting information about the complete interaction provides teachers with a tool to assess the individual...

  4. Virtual care

    DEFF Research Database (Denmark)

    Kamp, Annette; Aaløkke Ballegaard, Stinne

    of retrenchment, promising better quality, empowerment of citizens and work that is smarter and more qualified. Through ethnographic field studies we study the introduction of virtual home care in Danish elderly care, focusing on the implications for relational work and care relations. Virtual home care entails...... and professionals, and they instigate change in organization and professional identities. Studies, which more specifically deal with telecare, stress how virtualization alters the character of the observations care workers are able to make, and how the validity of the patients’ own measurements and observations...... point out how issues of trust and surveillance, which are always negotiated in care relations, are in fact accentuated in this kind of virtual care work. Moreover, we stress that the contemporary institutional context, organization and time schedules have a vast impact on the practices developed....

  5. Virtual Workshop

    DEFF Research Database (Denmark)

    Buus, Lillian; Bygholm, Ann

    In relation to the Tutor course in the Mediterranean Virtual University (MVU) project, a virtual workshop “Getting experiences with different synchronous communication media, collaboration, and group work” was held with all partner institutions in January 2006. More than 25 key-tutors within MVU...... participated from different institutions in the workshop. The result of the workshop was experiences with different communication tools and media. Facing the difficulties and possibilities in collaborateting virtually concerned around group work and development of a shared presentation. All based on getting...... experiences for the learning design of MVU courses. The workshop intented to give the participants the possibility to draw their own experiences with issues on computer supported collaboration, group work in a virtual environment, synchronous and asynchronous communication media, and different perspectives...

  6. Virtual Worlds for Virtual Organizing

    Science.gov (United States)

    Rhoten, Diana; Lutters, Wayne

    The members and resources of a virtual organization are dispersed across time and space, yet they function as a coherent entity through the use of technologies, networks, and alliances. As virtual organizations proliferate and become increasingly important in society, many may exploit the technical architecture s of virtual worlds, which are the confluence of computer-mediated communication, telepresence, and virtual reality originally created for gaming. A brief socio-technical history describes their early origins and the waves of progress followed by stasis that brought us to the current period of renewed enthusiasm. Examination of contemporary examples demonstrates how three genres of virtual worlds have enabled new arenas for virtual organizing: developer-defined closed worlds, user-modifiable quasi-open worlds, and user-generated open worlds. Among expected future trends are an increase in collaboration born virtually rather than imported from existing organizations, a tension between high-fidelity recreations of the physical world and hyper-stylized imaginations of fantasy worlds, and the growth of specialized worlds optimized for particular sectors, companies, or cultures.

  7. Finite Virtual State Machines

    OpenAIRE

    Senhadji Navarro, Raouf; García Vargas, Ignacio

    2012-01-01

    This letter proposes a new model of state machine called Finite Virtual State Machine (FVSM). A memory-based architecture and a procedure for generating FVSM implementations from Finite State Machines (FSMs) are presented. FVSM implementations provide advantages in speed over conventional RAM-based FSM implementations. The results of experiments prove the feasibility of this approach.

  8. Identification of putative estrogen receptor-mediated endocrine disrupting chemicals using QSAR- and structure-based virtual screening approaches

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Liying; Sedykh, Alexander; Tripathi, Ashutosh [Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC (United States); Zhu, Hao [The Rutgers Center for Computational and Integrative Biology, Rutgers University, Camden, NJ (United States); Department of Chemistry, Rutgers University, Camden, NJ (United States); Afantitis, Antreas; Mouchlis, Varnavas D.; Melagraki, Georgia [NovaMechanics Ltd., Nicosia (Cyprus); Rusyn, Ivan, E-mail: iir@unc.edu [Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC (United States); Tropsha, Alexander, E-mail: alex_tropsha@unc.edu [Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC (United States)

    2013-10-01

    Identification of endocrine disrupting chemicals is one of the important goals of environmental chemical hazard screening. We report on the development of validated in silico predictors of chemicals likely to cause estrogen receptor (ER)-mediated endocrine disruption to facilitate their prioritization for future screening. A database of relative binding affinity of a large number of ERα and/or ERβ ligands was assembled (546 for ERα and 137 for ERβ). Both single-task learning (STL) and multi-task learning (MTL) continuous quantitative structure–activity relationship (QSAR) models were developed for predicting ligand binding affinity to ERα or ERβ. High predictive accuracy was achieved for ERα binding affinity (MTL R{sup 2} = 0.71, STL R{sup 2} = 0.73). For ERβ binding affinity, MTL models were significantly more predictive (R{sup 2} = 0.53, p < 0.05) than STL models. In addition, docking studies were performed on a set of ER agonists/antagonists (67 agonists and 39 antagonists for ERα, 48 agonists and 32 antagonists for ERβ, supplemented by putative decoys/non-binders) using the following ER structures (in complexes with respective ligands) retrieved from the Protein Data Bank: ERα agonist (PDB ID: 1L2I), ERα antagonist (PDB ID: 3DT3), ERβ agonist (PDB ID: 2NV7), and ERβ antagonist (PDB ID: 1L2J). We found that all four ER conformations discriminated their corresponding ligands from presumed non-binders. Finally, both QSAR models and ER structures were employed in parallel to virtually screen several large libraries of environmental chemicals to derive a ligand- and structure-based prioritized list of putative estrogenic compounds to be used for in vitro and in vivo experimental validation. - Highlights: • This is the largest curated dataset inclusive of ERα and β (the latter is unique). • New methodology that for the first time affords acceptable ERβ models. • A combination of QSAR and docking enables prediction of affinity and function.

  9. Problem-orientiertes Lernen im virtuellen Raum: Erste Erfahrungen in der Nuklearmedizin [An approach towards problem-based learning in virtual space

    Directory of Open Access Journals (Sweden)

    Freudenberg, Lutz S.

    2010-11-01

    Full Text Available [english] Problem-based learning (PBL is an established and efficient approach to sustainable teaching. Here, we describe translation of PBL into the virtual classroom thereby offering novel teaching aspects in the field of Nuclear Medicine. Our teaching approach is implemented on a "moodle" platform and consists of 2 modules: complementary seminar teaching materials and a virtual PBL-classroom, which can be attended via Skype.Over the course of 4 semesters 539 students have accessed our teaching platform. 21 students have participated in the PBL seminar (module 2. After resolving some minor technical difficulties our virtual seminars have evolved into a forum of intense studies, whereby the participating students have learned to become more independent along the workup of the teaching cases. This was reflected in the results of the intra-group presentations and discussions.Quantitative and qualitative evaluation of our moodle-based PBL platform indicates an increasing level of acceptance and enthusiasm by the students. This has initiated discussions about opening our PBL concept to a wider audience within the university and beyond the Nuclear Medicine specialty.[german] Problem-orientiertes Lernen (POL ist eine etablierte und effiziente Methode zur nachhaltigen Lehre. In dem beschriebenen Projekt wurde der Versuch unternommen, das POL-Konzept in den virtuellen Raum zu übertragen, um die Lehre in der Nuklearmedizin zu ergänzen und motivierte Studierende für das Fach zu interessieren. Das Lehrprojekt auf Basis der Lehrplattform „moodle“ besteht aus zwei Teilen: Seminar-begleitende Seiten zur Nachbereitung der Vorlesung und ein virtueller POL-Bereich, in dem über eine Internet-basierte Telefonkonferenz POL-Fälle bearbeitet werden können. Insgesamt haben in vier Semestern 539 Studierende auf die Lehrplattform zugegriffen, von denen 21 an einem POL-Seminar teilgenommen haben. Nach anfänglichen – teils technischen – Schwierigkeiten

  10. vSphere virtual machine management

    CERN Document Server

    Fitzhugh, Rebecca

    2014-01-01

    This book follows a step-by-step tutorial approach with some real-world scenarios that vSphere businesses will be required to overcome every day. This book also discusses creating and configuring virtual machines and also covers monitoring virtual machine performance and resource allocation options. This book is for VMware administrators who want to build their knowledge of virtual machine administration and configuration. It's assumed that you have some experience with virtualization administration and vSphere.

  11. Virtual Specimens

    Science.gov (United States)

    de Paor, D. G.

    2009-12-01

    Virtual Field Trips have been around almost as long as the Worldwide Web itself yet virtual explorers do not generally return to their desktops with folders full of virtual hand specimens. Collection of real specimens on fields trips for later analysis in the lab (or at least in the pub) has been an important part of classical field geoscience education and research for generations but concern for the landscape and for preservation of key outcrops from wanton destruction has lead to many restrictions. One of the author’s favorite outcrops was recently vandalized presumably by a geologist who felt the need to bash some of the world’s most spectacular buckle folds with a rock sledge. It is not surprising, therefore, that geologists sometimes leave fragile localities out of field trip itineraries. Once analyzed, most specimens repose in drawers or bins, never to be seen again. Some end up in teaching collections but recent pedagogical research shows that undergraduate students have difficulty relating specimens both to their collection location and ultimate provenance in the lithosphere. Virtual specimens can be created using 3D modeling software and imported into virtual globes such as Google Earth (GE) where, they may be linked to virtual field trip stops or restored to their source localities on the paleo-globe. Sensitive localities may be protected by placemark approximation. The GE application program interface (API) has a distinct advantage over the stand-alone GE application when it comes to viewing and manipulating virtual specimens. When instances of the virtual globe are embedded in web pages using the GE plug-in, Collada models of specimens can be manipulated with javascript controls residing in the enclosing HTML, permitting specimens to be magnified, rotated in 3D, and sliced. Associated analytical data may be linked into javascript and localities for comparison at various points on the globe referenced by ‘fetching’ KML. Virtual specimens open up

  12. Similarity Solutions of MHD Mixed Convection Flow with Variable Reactive Index, Magnetic Field, and Velocity Slip Near a Moving Horizontal Plate: A Group Theory Approach

    Directory of Open Access Journals (Sweden)

    W. A. Khan

    2012-01-01

    Full Text Available The mixed convection of Newtonian fluid flow along a moving horizontal plate with higher-order chemical reaction, variable concentration reactant, and variable wall temperature and concentration is considered. Velocity slip and the thermal convective boundary conditions are applied at the plate surface. The governing partial differential equations are transformed into similarity equations via dimensionless similarity transformations developed by one-parameter continuous group method. The numerical solutions of the transformed ordinary differential equations are constructed for velocity, temperature and concentration functions, the skin friction factor, the rate of heat, and the rate of mass transfer using an implicit finite difference numerical technique. The investigated parameters are buoyancy parameters , , chemical reaction parameter , suction/injection parameter , velocity slip parameter convective heat transfer parameter , magnetic parameter , Prandtl number Pr and Schmidt number, Sc. Comparison with results from the open literature shows a very good agreement.

  13. A Virtual Mixture Approach to the Study of Multistate Equilibrium: Application to Constant pH Simulation in Explicit Water.

    Science.gov (United States)

    Wu, Xiongwu; Brooks, Bernard R

    2015-10-01

    Chemical and thermodynamic equilibrium of multiple states is a fundamental phenomenon in biology systems and has been the focus of many experimental and computational studies. This work presents a simulation method to directly study the equilibrium of multiple states. This method constructs a virtual mixture of multiple states (VMMS) to sample the conformational space of all chemical states simultaneously. The VMMS system consists of multiple subsystems, one for each state. The subsystem contains a solute and a solvent environment. The solute molecules in all subsystems share the same conformation but have their own solvent environments. Transition between states is implicated by the change of their molar fractions. Simulation of a VMMS system allows efficient calculation of relative free energies of all states, which in turn determine their equilibrium molar fractions. For systems with a large number of state transition sites, an implicit site approximation is introduced to minimize the cost of simulation. A direct application of the VMMS method is for constant pH simulation to study protonation equilibrium. Applying the VMMS method to a heptapeptide of 3 ionizable residues, we calculated the pKas of those residues both with all explicit states and with implicit sites and obtained consistent results. For mouse epidermal growth factor of 9 ionizable groups, our VMMS simulations with implicit sites produced pKas of all 9 ionizable groups and the results agree qualitatively with NMR measurement. This example demonstrates the VMMS method can be applied to systems of a large number of ionizable groups and the computational cost scales linearly with the number of ionizable groups. For one of the most challenging systems in constant pH calculation, SNase Δ+PHS/V66K, our VMMS simulation shows that it is the state-dependent water penetration that causes the large deviation in lysine66's pKa.

  14. Material and Virtuality

    DEFF Research Database (Denmark)

    Kruse Aagaard, Anders

    2015-01-01

    Through tangible experiments this paper discusses the dialogues between digital architectural drawing and the process of materialisation. The paper sets op the spans between virtual and actual and control and uncertainty making these oppositions a combined spaces where information between a digital...... world and a physical world can interchange. The paper suggest an approach where an overlapping of virtuality and the tangible material output from digital fabrication machines create a method of using materialisation tools as instruments to connect the reality of materials and to an exploring process...... through these experiments is both tangible and directly connected to real actions in digital drawing or material processing but also the base for theoretical contemplations of the relation between virtual and actual and control and uncertainty....

  15. Introduction to vector velocity imaging

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Udesen, Jesper; Hansen, Kristoffer Lindskov

    over the full region of interest and a real time image at a frame rate of 20 Hz can be displayed. Real time videos have been obtained from both our research systems and from commercial BK Medical scanners. The vector velocity images reveal the full complexity of the human blood flow. It is easy to see...... direction and the correct velocity magnitude for any orientation of the vessels. At complex geometries like bifurcations, branching and for valves the approach reveals how the velocity changes magnitude and direction over the cardiac cycle. Vector velocity reveals a wealth of new information that now...... is accessible to the ultrasound community. The displaying and studying of this information is challenging as complex flow changes rapidly over the cardiac cycle....

  16. Virtual environments for the transfer of navigation skills in the blind: a comparison of directed instruction vs. video game based learning approaches

    Science.gov (United States)

    Connors, Erin C.; Chrastil, Elizabeth R.; Sánchez, Jaime; Merabet, Lotfi B.

    2014-01-01

    For profoundly blind individuals, navigating in an unfamiliar building can represent a significant challenge. We investigated the use of an audio-based, virtual environment called Audio-based Environment Simulator (AbES) that can be explored for the purposes of learning the layout of an unfamiliar, complex indoor environment. Furthermore, we compared two modes of interaction with AbES. In one group, blind participants implicitly learned the layout of a target environment while playing an exploratory, goal-directed video game. By comparison, a second group was explicitly taught the same layout following a standard route and instructions provided by a sighted facilitator. As a control, a third group interacted with AbES while playing an exploratory, goal-directed video game however, the explored environment did not correspond to the target layout. Following interaction with AbES, a series of route navigation tasks were carried out in the virtual and physical building represented in the training environment to assess the transfer of acquired spatial information. We found that participants from both modes of interaction were able to transfer the spatial knowledge gained as indexed by their successful route navigation performance. This transfer was not apparent in the control participants. Most notably, the game-based learning strategy was also associated with enhanced performance when participants were required to find alternate routes and short cuts within the target building suggesting that a ludic-based training approach may provide for a more flexible mental representation of the environment. Furthermore, outcome comparisons between early and late blind individuals suggested that greater prior visual experience did not have a significant effect on overall navigation performance following training. Finally, performance did not appear to be associated with other factors of interest such as age, gender, and verbal memory recall. We conclude that the highly interactive

  17. Virtual environments for the transfer of navigation skills in the blind: a comparison of directed instruction vs. video game based learning approaches.

    Science.gov (United States)

    Connors, Erin C; Chrastil, Elizabeth R; Sánchez, Jaime; Merabet, Lotfi B

    2014-01-01

    For profoundly blind individuals, navigating in an unfamiliar building can represent a significant challenge. We investigated the use of an audio-based, virtual environment called Audio-based Environment Simulator (AbES) that can be explored for the purposes of learning the layout of an unfamiliar, complex indoor environment. Furthermore, we compared two modes of interaction with AbES. In one group, blind participants implicitly learned the layout of a target environment while playing an exploratory, goal-directed video game. By comparison, a second group was explicitly taught the same layout following a standard route and instructions provided by a sighted facilitator. As a control, a third group interacted with AbES while playing an exploratory, goal-directed video game however, the explored environment did not correspond to the target layout. Following interaction with AbES, a series of route navigation tasks were carried out in the virtual and physical building represented in the training environment to assess the transfer of acquired spatial information. We found that participants from both modes of interaction were able to transfer the spatial knowledge gained as indexed by their successful route navigation performance. This transfer was not apparent in the control participants. Most notably, the game-based learning strategy was also associated with enhanced performance when participants were required to find alternate routes and short cuts within the target building suggesting that a ludic-based training approach may provide for a more flexible mental representation of the environment. Furthermore, outcome comparisons between early and late blind individuals suggested that greater prior visual experience did not have a significant effect on overall navigation performance following training. Finally, performance did not appear to be associated with other factors of interest such as age, gender, and verbal memory recall. We conclude that the highly interactive

  18. The contrast-source stress-velocity integral-equation formulation of three-dimensional time-domain elastodynamic scattering problems : A structured approach using tensor partitioning

    NARCIS (Netherlands)

    De Hoop, A.T.; Abubakar, A.; Habashy, T.M.

    2009-01-01

    The contrast-source stress-velocity integral-equation formulation of three-dimensional time-domain elastodynamic scattering problems is discussed. A novel feature of the formulation is a tensor partitioning of the relevant dynamic stress and the contrast source volume density of deformation rate.

  19. Virtual Violence.

    Science.gov (United States)

    2016-08-01

    In the United States, exposure to media violence is becoming an inescapable component of children's lives. With the rise in new technologies, such as tablets and new gaming platforms, children and adolescents increasingly are exposed to what is known as "virtual violence." This form of violence is not experienced physically; rather, it is experienced in realistic ways via new technology and ever more intense and realistic games. The American Academy of Pediatrics continues to be concerned about children's exposure to virtual violence and the effect it has on their overall health and well-being. This policy statement aims to summarize the current state of scientific knowledge regarding the effects of virtual violence on children's attitudes and behaviors and to make specific recommendations for pediatricians, parents, industry, and policy makers. Copyright © 2016 by the American Academy of Pediatrics.

  20. Virtual Sustainability

    Directory of Open Access Journals (Sweden)

    William Sims Bainbridge

    2010-09-01

    Full Text Available In four ways, massively multiplayer online role-playing games may serve as tools for advancing sustainability goals, and as laboratories for developing alternatives to current social arrangements that have implications for the natural environment. First, by moving conspicuous consumption and other usually costly status competitions into virtual environments, these virtual worlds might reduce the need for physical resources. Second, they provide training that could prepare individuals to be teleworkers, and develop or demonstrate methods for using information technology to replace much transportation technology, notably in commuting. Third, virtual worlds and online games build international cooperation, even blending national cultures, thereby inching us toward not only the world consciousness needed for international agreements about the environment, but also toward non-spatial government that cuts across archaic nationalisms. Finally, realizing the potential social benefits of this new technology may urge us to reconsider a number of traditional societal institutions.

  1. Vector blood velocity estimation in medical ultrasound

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Gran, Fredrik; Udesen, Jesper

    2006-01-01

    Two methods for making vector velocity estimation in medical ultrasound are presented. All of the techniques can find both the axial and transverse velocity in the image and can be used for displaying both the correct velocity magnitude and direction. The first method uses a transverse oscillation...... in the ultrasound field to find the transverse velocity. In-vivo examples from the carotid artery are shown, where complex turbulent flow is found in certain parts of the cardiac cycle. The second approach uses directional beam forming along the flow direction to estimate the velocity magnitude. Using a correlation...

  2. Identification of potential Gly/NMDA receptor antagonists by cheminformatics approach: a combination of pharmacophore modelling, virtual screening and molecular docking studies.

    Science.gov (United States)

    Ugale, V G; Bari, S B

    2016-01-01

    The Gly/NMDA receptor has become known as potential target for the management of neurodegenerative diseases. Discovery of Gly/NMDA antagonists has thus attracted much attention in recent years. In the present research, a cheminformatics approach has been used to determine structural requirements for Gly/NMDA antagonism and to identify potential antagonists. Here, 37 quinoxaline derivatives were selected to develop a significant pharmacophore model with good certainty. The selected model was validated by leave-one-out cross-validation, an external test set, decoy set and Y-randomization test. Applicability domain was verified by the standardization approach. The validated 3D-QSAR model was used to screen virtual hits from the ZINC database by pharmacophore mapping. Molecular docking was used for assessment of receptor-ligand binding modes and binding affinities. The GlideScore and molecular interactions with critical amino acids were considered as crucial features to identify final hits. Furthermore, hits were analysed for in silico pharmacokinetic parameters and Lipinski's rule of five, demonstrating their potential as drug-like candidates. The PubChem and SciFinder search tools were used to authenticate the novelty of leads retrieved. Finally, five different leads have been suggested as putative novel candidates for the exploration of potent Gly/NMDA receptor antagonists.

  3. Providing Virtual Execution Environments: A Twofold Illustration

    CERN Document Server

    Grehant, Xavier

    2008-01-01

    Platform virtualization helps solving major grid computing challenges: share resource with flexible, user-controlled and custom execution environments and in the meanwhile, isolate failures and malicious code. Grid resource management tools will evolve to embrace support for virtual resource. We present two open source projects that transparently supply virtual execution environments. Tycoon has been developed at HP Labs to optimise resource usage in creating an economy where users bid to access virtual machines and compete for CPU cycles. SmartDomains provides a peer-to-peer layer that automates virtual machines deployment using a description language and deployment engine from HP Labs. These projects demonstrate both client-server and peer-to-peer approaches to virtual resource management. The first case makes extensive use of virtual machines features for dynamic resource allocation. The second translates virtual machines capabilities into a sophisticated language where resource management components can b...

  4. Modelling Virtual Environments for Geovisualization

    DEFF Research Database (Denmark)

    Bodum, Lars

    2005-01-01

    The use of virtual environments in geovisualization has become a major topic within the last few years. The main reason for this interest in the growing use of 3D models and visual realizations in a wide range of applications concerned with the geographic element of information. The implementation...... and use of virtual environments has developed form being a rather sophisticated type of visualization that demanded extreme computer resources to become an integral part of the software on every desktop computer. This chapter addresses both philosophical and technical issues regarding the modelling...... of virtual environments. It specifically focuses on different representational aspects to be taken into consideration when a virtual environment is created. These aspects are data modelling, 3D modelling and level-of-detail. A range of different approaches can be taken to visualize a virtual environment...

  5. Robotics virtual rail system and method

    Science.gov (United States)

    Bruemmer, David J [Idaho Falls, ID; Few, Douglas A [Idaho Falls, ID; Walton, Miles C [Idaho Falls, ID

    2011-07-05

    A virtual track or rail system and method is described for execution by a robot. A user, through a user interface, generates a desired path comprised of at least one segment representative of the virtual track for the robot. Start and end points are assigned to the desired path and velocities are also associated with each of the at least one segment of the desired path. A waypoint file is generated including positions along the virtual track representing the desired path with the positions beginning from the start point to the end point including the velocities of each of the at least one segment. The waypoint file is sent to the robot for traversing along the virtual track.

  6. UTILITY OF DOPPLER ULTRASOUND PORTAL VEIN VELOCITY MEASUREMENT IN THE EVALUATION OF NON-ALCOHOLIC FATTY LIVER DISEASE: A CASE-BASED APPROACH OF THE LITERATURE

    Directory of Open Access Journals (Sweden)

    Andrei Vasile OLTEANU

    2016-06-01

    Full Text Available Background: Non-alcoholic fatty liver disease (NAFLD is becoming one of the most frequent liver diseases worldwide, and great difficulties are encountered nowadays for finding non-invasive, sensitive, specific and reproducible workup methods to help these patients. The aim of our study is to assess literature findings on the utility of evaluating portal vein velocity with Doppler ultrasonography (US in patients affected with NAFLD, and to discuss a series of such cases vs different US findings. A relationship between portal vein velocity and stage or progression on NAFLD would suggest that such an alternative, non-invasive and reproducible examination could be used in the management of noncirrhotic NAFLD patients. The basis of such a relationship would be the presumed reduction in liver and hepatic vascular compliance, associated with an increase in hepatic vascular resistance in such patients. Although previously considered a non-reproducible and operator-dependent examination, Doppler US assessment of the portal venous velocity is now viewed by more and more practitioners as a useful tool at least in what follow-up and detection of complications in NAFLD patients is concerned.

  7. Virtual Learning

    Science.gov (United States)

    Cvetkovic, Dragan, Ed.

    2016-01-01

    The first chapter provides an overview of the popular systems for distance learning. In the second chapter, a review of all major social and economic activities in order to improve the system of virtual learning is given. The third chapter deals with the influence of technology in the management of educational institutions. The fourth chapter…

  8. Virtual Reality.

    Science.gov (United States)

    Newby, Gregory B.

    1993-01-01

    Discusses the current state of the art in virtual reality (VR), its historical background, and future possibilities. Highlights include applications in medicine, art and entertainment, science, business, and telerobotics; and VR for information science, including graphical display of bibliographic data, libraries and books, and cyberspace.…

  9. Virtual Classroom

    DEFF Research Database (Denmark)

    Christensen, Ove

    2013-01-01

    In the Scandinavian countries: Sweden, Norway and Denmark, the project GNU (Grænseoverskridende Nordisk Undervisning, i.e. Transnational Nordic Teaching) is experimenting with ways of conducting teaching across the borders in the elementary schools. The cloud classes are organised with one class ...... and benefits in regard to learning and pedagogy with virtual classroom....

  10. Virtualize Me!

    Science.gov (United States)

    Waters, John K.

    2009-01-01

    John Abdelmalak, director of technology for the School District of the Chathams, was pretty sure it was time to jump on the virtualization bandwagon last year when he invited Dell to conduct a readiness assessment of his district's servers. When he saw just how little of their capacity was being used, he lost all doubt. Abdelmalak is one of many…

  11. Virtual Savannah

    DEFF Research Database (Denmark)

    Rodil, Kasper; Eskildsen, Søren; Rehm, Matthias

    2012-01-01

    Virtual Savannah is constructed to visualize parts of a curriculum, which the educational service at Aalborg Zoo has difficulties in teaching children visiting the zoo. It contains rich media like audio, text, video and picture galleries about African ecology, but some of this episodic information...

  12. Virtual patrolling

    NARCIS (Netherlands)

    van der Vlist, M.; Wismans, Luc Johannes Josephus; van Beek, P.; Suijs, L.C.W.

    2016-01-01

    Approximately 25 per cent of all congestion on motorways is caused by incidents. By virtual patrolling, incidents e.g. queues, accidents and car breakdowns on a road network, can be predicted or detected in an early stage. This early detection and prediction of an incident likely to happen, offers

  13. Virtual patrolling.

    NARCIS (Netherlands)

    van der Vlist, M.; Wismans, Luc Johannes Josephus; van Beek, P.; Suijs, L.C.W.

    2016-01-01

    Approximately 25 per cent of all congestion on motorways is caused by incidents. By virtual patrolling, incidents e.g. queues, accidents and car breakdowns on a road network, can be predicted or detected in an early stage. This early detection and prediction of an incident likely to happen, offers

  14. Cyber nursing--health 'experts' approaches in the post-modern era of virtual performances: a nethnography study.

    Science.gov (United States)

    Eriksson, Henrik; Salzmann-Erikson, Martin

    2013-03-01

    The imperative to gather information online and to become an 'expert' by locating effective advice for oneself and others is a fairly new support phenomenon in relation to health advice. The creation of new positions for health 'experts' within the space of the Internet has been addressed as a cybernursing activity. A focused analysis of communication in health forums might give insight into the new roles that are available for health experts in cyberspace. The aim of this study is to describe approaches to being an 'expert' in lifestyle health choice forums on the Internet and to elaborate on the communicative performances that take place in the forums. An archival and cross-sectional observational forum study was undertaken using principles for conducting ethnographic research online. 2640 pages of data from two health Internet forums were gathered and analyzed. The results reveal three distinctive types of experts that emerge in the forums: (1) those that build their expertise by creating a presence in the forum based on lengthy and frequent postings, (2) those who build a presence through reciprocal exchanges with individual posters with questions or concerns, and (3) those who build expertise around a "life long learning" perspective based on logic and reason. The results suggest that experts not only co-exist in the forums, but more importantly they reinforce each others' positions. This effect is central; alongside one another, the posts of the three types of experts we identify constitute a whole for those seeking the forum for advice and support. Users are provided with strong opinions and advice, support and Socratic reasoning, and a problem-oriented approach. The Internet is now an integral part of everyday living, not least of which among those who seek and offer support in cyberspace. As such, cyber nursing has become an important activity to monitor, and formal health care professionals and nursing researchers must stay abreast of developments

  15. A QSAR approach for virtual screening of lead-like molecules en route to antitumor and antibiotic drugs from marine and microbial natural products

    Directory of Open Access Journals (Sweden)

    Florbela Pereira

    2014-05-01

    Figure 1. The unreported 15 lead antibiotic MNPs and MbNPs from AntiMarin database, using the best Rfs antibiotic model with a probability of being antibiotic greater than or equal to 0.8. Figure 2. The selected 4 lead antitumor MNPs and MbNPs from the AntiMarin database, using the best Rfs antitumor model with a probability of being antitumor greater than or equal to 0.8. The present work corroborates by one side the results of our previous work6 and enables the presentation of a new set of possible lead like bioactive compounds. Additionally, it is shown the usefulness of quantum-chemical descriptors in the discrimination of biological active and inactive compounds. The use of the εHOMO quantum-chemical descriptor in the discrimination of large scale data sets of lead-like or drug-like compounds has never been reported. This approach results in the reduction, in great extent, of the number of compounds used in real screens, and it reinforces the results of our previous work. Furthermore, besides the virtual screening, the computational methods can be very useful to build appropriate databases, allowing for effective shortcuts of NP extracts dereplication procedures, which will certainly result in increasing the efficiency of drug discovery.

  16. Impact of virtual learning environment (VLE): A technological approach to genetics teaching on high school students' content knowledge, self-efficacy and career goal aspirations

    Science.gov (United States)

    Kandi, Kamala M.

    This study examines the effect of a technology-based instructional tool 'Geniverse' on the content knowledge gains, Science Self-Efficacy, Technology Self-Efficacy, and Career Goal Aspirations among 283 high school learners. The study was conducted in four urban high schools, two of which have achieved Adequate Yearly Progress (AYP) and two have not. Students in both types of schools were taught genetics either through Geniverse, a virtual learning environment or Dragon genetics, a paper-pencil activity embedded in traditional instructional method. Results indicated that students in all schools increased their knowledge of genetics using either type of instructional approach. Students who were taught using Geniverse demonstrated an advantage for genetics knowledge although the effect was small. These increases were more pronounced in the schools that had been meeting the AYP goal. The other significant effect for Geniverse was that students in the technology-enhanced classrooms increased in science Self-Efficacy while students in the non-technology enhanced classrooms decreased. In addition, students from Non-AYP schools showed an improvement in Science and Technology Self-Efficacy; however the effects were small. The implications of these results for the future use of technology-enriched classrooms were discussed. Keywords: Technology-based instruction, Self-Efficacy, career goals and Adequate Yearly Progress (AYP).

  17. Portable Userspace Virtual Filesystem Switch

    OpenAIRE

    Łukasz Faber; Krzysztof Boryczko

    2013-01-01

    Multiple different filesystems — including disk-based, network, distributed, abstract — arean integral part of every operating system. They are usually written as kernel modules and abstracted to the user via a virtual filesystem switch. In this paper we analyse the feasibility of reimplementing the virtual filesystem switch as a userspace daemon and applicability of this approach in real-life usage. Such reimplementation will require a way to virtualise processes behaviour related to filesys...

  18. Identification of New Natural DNA G-Quadruplex Binders Selected by a Structure-Based Virtual Screening Approach

    Directory of Open Access Journals (Sweden)

    Stefano Alcaro

    2013-09-01

    Full Text Available The G-quadruplex DNA structures are mainly present at the terminal portion of telomeres and can be stabilized by ligands able to recognize them in a specific manner. The recognition process is usually related to the inhibition of the enzyme telomerase indirectly involved and over-expressed in a high percentage of human tumors. There are several ligands, characterized by different chemical structures, already reported in the literature for their ability to bind and stabilize the G-quadruplex structures. Using the structural and biological information available on these structures; we performed a high throughput in silico screening of commercially natural compounds databases by means of a structure-based approach followed by docking experiments against the human telomeric sequence d[AG3(T2AG33]. We identified 12 best hits characterized by different chemical scaffolds and conformational and physicochemical properties. All of them were associated to an improved theoretical binding affinity with respect to that of known selective G-binders. Among these hits there is a chalcone derivative; structurally very similar to the polyphenol butein; known to remarkably inhibit the telomerase activity.

  19. Virtual Presenters: Towards Interactive Virtual Presentations

    NARCIS (Netherlands)

    Nijholt, Antinus; Cappellini, V.; Hemsley, J.

    2005-01-01

    We discuss having virtual presenters in virtual environments that present information to visitors of these environments. Some current research is surveyed and we will look in particular to our research in the context of a virtual meeting room where a virtual presenter uses speech, gestures, pointing

  20. Sensorial Virtualization: Coupling Gaming and Virtual Environment

    NARCIS (Netherlands)

    Garbaya, S.; Miraoui, C.; Wendrich, Robert E.; Lim, T.; Stanescu, I.A.; Hauge, J.B.

    2014-01-01

    Virtual reality and virtualization are currently used to design complex systems and demonstrate that they represent the functionalities of real systems. However, the design refinement of the virtual environment (VE) and distributed virtual environment (DVE) are still time consuming and costly, as it

  1. Manually locating physical and virtual reality objects.

    Science.gov (United States)

    Chen, Karen B; Kimmel, Ryan A; Bartholomew, Aaron; Ponto, Kevin; Gleicher, Michael L; Radwin, Robert G

    2014-09-01

    In this study, we compared how users locate physical and equivalent three-dimensional images of virtual objects in a cave automatic virtual environment (CAVE) using the hand to examine how human performance (accuracy, time, and approach) is affected by object size, location, and distance. Virtual reality (VR) offers the promise to flexibly simulate arbitrary environments for studying human performance. Previously, VR researchers primarily considered differences between virtual and physical distance estimation rather than reaching for close-up objects. Fourteen participants completed manual targeting tasks that involved reaching for corners on equivalent physical and virtual boxes of three different sizes. Predicted errors were calculated from a geometric model based on user interpupillary distance, eye location, distance from the eyes to the projector screen, and object. Users were 1.64 times less accurate (p virtual versus physical box corners using the hands. Predicted virtual targeting errors were on average 1.53 times (p virtual targets but not significantly different for close-up virtual targets. Target size, location, and distance, in addition to binocular disparity, affected virtual object targeting inaccuracy. Observed virtual box inaccuracy was less than predicted for farther locations, suggesting possible influence of cues other than binocular vision. Human physical interaction with objects in VR for simulation, training, and prototyping involving reaching and manually handling virtual objects in a CAVE are more accurate than predicted when locating farther objects.

  2. Biosimilars clinical development program: confirmatory clinical trials: a virtual/simulated case study comparing equivalence and non-inferiority approaches.

    Science.gov (United States)

    Fletcher, Mark P

    2011-09-01

    As part of long term commitment of the Biologicals and Vaccines Committee (B&V) of the International Federation of Pharmaceutical Manufacturers and Association (IFPMA) to provide expert input to the WHO on their recently finalized GUIDELINES ON EVALUATION OF SIMILAR BIOTHERAPEUTIC PRODUCTS (SBPs), and in response to WHO's request, the IFPMA B&V prepared a clinical case study at a recent WHO workshop in Seoul, Korea. The case study, presented by Mark Fletcher on behalf of B&V, involved a model scenario for a clinical efficacy trial to support the approval of a Similar Biotherapeutic Product (SBP) as part of the required comparative clinical program against a Reference Biotherapeutic Product (RBP). A key goal was to understand and illustrate key clinical and statistical principles, and considerations described in the WHO Guidance for regulatory authorities when designing and implementing WHO guidelines and post-approval regulatory oversight for SBPs. Using this model SBP/RBP pair, an interactive discussion was carried out among the workshop participants on the pros and cons of using equivalence vs. non-inferiority designs to assess the two products' similarity. Through discussion of the case, the complexity of demonstrating similar efficacy and safety of a SBP vs. RBP for biotherapeutic products is outlined and discussed in the context of the key principles laid out in the recently published WHO GUIDELINES ON EVALUATION OF SIMILAR BIOTHERAPEUTIC PRODUCTS (SBPs). The exercise illustrates the need for a case-by-case approach when interpreting clinical data from SBP dossiers to adequately assure similar efficacy and safety of SBPs for any studied indication. Copyright © 2011. Published by Elsevier Ltd.

  3. Virtual Goods Recommendations in Virtual Worlds

    OpenAIRE

    Kuan-Yu Chen; Hsiu-Yu Liao; Jyun-Hung Chen; Duen-Ren Liu

    2015-01-01

    Virtual worlds (VWs) are computer-simulated environments which allow users to create their own virtual character as an avatar. With the rapidly growing user volume in VWs, platform providers launch virtual goods in haste and stampede users to increase sales revenue. However, the rapidity of development incurs virtual unrelated items which will be difficult to remarket. It not only wastes virtual global companies’ intelligence resources, but also makes it difficult for users to find suitable v...

  4. Algorithms for estimating blood velocities using ultrasound

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt

    2000-01-01

    have been developed for performing the estimation, and the various approaches are described. The current systems only display the velocity along the ultrasound beam direction and a velocity transverse to the beam is not detected. This is a major problem in these systems, since most blood vessels...

  5. Virtual Training of the Myosignal.

    Science.gov (United States)

    Terlaak, Bernhard; Bouwsema, Hanneke; van der Sluis, Corry K; Bongers, Raoul M

    2015-01-01

    To investigate which of three virtual training methods produces the largest learning effects on discrete and continuous myocontrol. The secondary objective was to examine the relation between myocontrol and manual motor control tests. A cohort analytic study. University laboratory. 3 groups of 12 able-bodied participants (N = 36). Participants trained the control over their myosignals on 3 consecutive days. Training was done with either myosignal feedback on a computer screen, a virtual myoelectric prosthetic hand or a computer game. Participants performed 2 myocontrol tests and 2 manual motor control tests before the first and after the last training session. They were asked to open and close a virtual prosthetic hand on 3 different velocities as a discrete myocontrol test and followed a line with their myosignals for 30 seconds as a continuous myocontrol test. The motor control tests were a pegboard and grip-force test. Discrete myocontrol test: mean velocities. Continuous myocontrol test: error and error SD. Pegboard test: time to complete. Grip-force test: produced forces. No differences in learning effects on myocontrol were found for the different virtual training methods. Discrete myocontrol ability did not significantly improve as a result of training. Continuous myocontrol ability improved significantly as a result of training, both on average control and variability. All correlations between the motor control and myocontrol test outcome measures were below .50. Three different virtual training methods showed comparable results when learning myocontrol. Continuous myocontrol was improved by training while discrete myocontrol was not. Myocontrol ability could not be predicted by the manual motor control tests.

  6. Virtual Training of the Myosignal.

    Directory of Open Access Journals (Sweden)

    Bernhard Terlaak

    Full Text Available To investigate which of three virtual training methods produces the largest learning effects on discrete and continuous myocontrol. The secondary objective was to examine the relation between myocontrol and manual motor control tests.A cohort analytic study.University laboratory.3 groups of 12 able-bodied participants (N = 36.Participants trained the control over their myosignals on 3 consecutive days. Training was done with either myosignal feedback on a computer screen, a virtual myoelectric prosthetic hand or a computer game. Participants performed 2 myocontrol tests and 2 manual motor control tests before the first and after the last training session. They were asked to open and close a virtual prosthetic hand on 3 different velocities as a discrete myocontrol test and followed a line with their myosignals for 30 seconds as a continuous myocontrol test. The motor control tests were a pegboard and grip-force test.Discrete myocontrol test: mean velocities. Continuous myocontrol test: error and error SD. Pegboard test: time to complete. Grip-force test: produced forces.No differences in learning effects on myocontrol were found for the different virtual training methods. Discrete myocontrol ability did not significantly improve as a result of training. Continuous myocontrol ability improved significantly as a result of training, both on average control and variability. All correlations between the motor control and myocontrol test outcome measures were below .50.Three different virtual training methods showed comparable results when learning myocontrol. Continuous myocontrol was improved by training while discrete myocontrol was not. Myocontrol ability could not be predicted by the manual motor control tests.

  7. Periodismo virtual

    Directory of Open Access Journals (Sweden)

    Carlos Morales

    2015-01-01

    Full Text Available El periodismo virtual se produce en diarios que no ofrecen noticias (concebidas como versión o reflejo de la realidad sino que crean sus propias ficciones, especialmente en primeras planas. El autor del artículo señala que esto esta sucediendo en LA NACIÓN de San José de Costa Rica, diario premiado por la inefable Sociedad Interamericana de Prensa - SIP - y periódico económicamente más importante del país.

  8. Estimating blood flow velocity in angiographic image data

    Science.gov (United States)

    Hentschke, Clemens M.; Serowy, Steffen; Janiga, Gábor; Rose, Georg; Tönnies, Klaus D.

    2011-03-01

    We propose a system to estimate blood flow velocity in angiographic image data for patient-specific blood flow simulations. Angiographies are acquired routinely for diagnosis and before treatment of vascular diseases. Projective blood flow is measured in digital subtraction X-ray angiography (2D-DSA) images by tracking contrast agent propagation. Spatial information is added by re-projecting 2D centerline pixels to the reconstructed 3D X-ray rotation angiography (3D-RA) data of the same subject. Ambiguities caused by occluding vessels from the virtual viewpoint of the acquired 2D-DSA image are resolved by a graph-based approach. The blood flow velocity can be used as boundary condition for exact blood flow simulations that can help physicians to understand hemodynamics of the vasculature. Our focus is to analyze cerebral angiographic data. We performed several experiments with phantom and patient data that proved the accuracy and the functionality of our method. We evaluated experimentally the projective flow estimation method and the re-projection method. We measured mean deviations to the ground truth between 11 % and 15.7 % for phantom data. We also showed the ability of our method to produce plausible results with patient-data.

  9. High-Velocity Clouds

    NARCIS (Netherlands)

    Wakker, Bart P.; Woerden, Hugo van; Oswalt, Terry D.; Gilmore, Gerard

    2013-01-01

    The high-velocity clouds (HVCs) are gaseous objects that do not partake in differential galactic rotation, but instead have anomalous velocities. They trace energetic processes on the interface between the interstellar material in the Galactic disk and intergalactic space. Three different processes

  10. Earthquake Safety Training through Virtual Drills.

    Science.gov (United States)

    Li, Changyang; Liang, Wei; Quigley, Chris; Zhao, Yibiao; Yu, Lap-Fai

    2017-04-01

    Recent popularity of consumer-grade virtual reality devices, such as the Oculus Rift and the HTC Vive, has enabled household users to experience highly immersive virtual environments. We take advantage of the commercial availability of these devices to provide an immersive and novel virtual reality training approach, designed to teach individuals how to survive earthquakes, in common indoor environments. Our approach makes use of virtual environments realistically populated with furniture objects for training. During a training, a virtual earthquake is simulated. The user navigates in, and manipulates with, the virtual environments to avoid getting hurt, while learning the observation and self-protection skills to survive an earthquake. We demonstrated our approach for common scene types such as offices, living rooms and dining rooms. To test the effectiveness of our approach, we conducted an evaluation by asking users to train in several rooms of a given scene type and then test in a new room of the same type. Evaluation results show that our virtual reality training approach is effective, with the participants who are trained by our approach performing better, on average, than those trained by alternative approaches in terms of the capabilities to avoid physical damage and to detect potentially dangerous objects.

  11. Realidad virtual y materialidad

    OpenAIRE

    Pérez Herranz, Fernando Miguel

    2009-01-01

    1. Fenomenología de partida: Real / Simbólico / Imaginario 2. Realidad 3. Virtual 3.1. Virtual / real / posible / probable 3.2. Los contextos de la realidad virtual A) REALIDAD VIRTUAL INMERSIVA B) REALIDAD VIRTUAL NO INMERSIVA C) REALIDAD VIRTUAL Y DIGITALIZACIÓN 3.3. Cruce virtual / real 3.4. Cuestiones filosóficas 4. Materialidad 5. Materialidad y descentramiento 5.1. Ejemplos de descentramiento en los contextos de Realidad Virtual A’) DUALISMO CARTESIANO, CUERPO Y «CIBORG » B’) EL ESPÍRIT...

  12. Microsoft Virtualization Master Microsoft Server, Desktop, Application, and Presentation Virtualization

    CERN Document Server

    Olzak, Thomas; Boomer, Jason; Keefer, Robert M

    2010-01-01

    Microsoft Virtualization helps you understand and implement the latest virtualization strategies available with Microsoft products. This book focuses on: Server Virtualization, Desktop Virtualization, Application Virtualization, and Presentation Virtualization. Whether you are managing Hyper-V, implementing desktop virtualization, or even migrating virtual machines, this book is packed with coverage on all aspects of these processes. Written by a talented team of Microsoft MVPs, Microsoft Virtualization is the leading resource for a full installation, migration, or integration of virtual syste

  13. Towards Role Detection in Virtual Worlds

    NARCIS (Netherlands)

    C. Eickhoff (Carsten); V.P. Lavrenko

    2012-01-01

    htmlabstractVirtual worlds are a topic of steadily growing relevance. Some of the providers report user numbers that exceed the population of entire nations in the real world. Virtual worlds typically provide a high degree of complexity, which in some areas approaches the real world's richness of

  14. Virtual Images: Going through the Looking Glass

    Science.gov (United States)

    Mota, Ana Rita; Lopes dos Santos, João

    2017-01-01

    Virtual images are often introduced through a "geometric" perspective, with little conceptual or qualitative illustrations, hindering a deeper understanding of this physical concept. In this paper, we present two rather simple observations that force a critical reflection on the optical nature of a virtual image. This approach is…

  15. Developing virtual patients for medical microbiology education.

    Science.gov (United States)

    McCarthy, David; O'Gorman, Ciaran; Gormley, Gerry J

    2013-12-01

    The landscape of medical education is changing as students embrace the accessibility and interactivity of e-learning. Virtual patients are e-learning resources that may be used to advance microbiology education. Although the development of virtual patients has been widely considered, here we aim to provide a coherent approach for clinical educators. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Virtual Manipulatives in the K-12 Classroom.

    Science.gov (United States)

    Moyer, Patricia S.; Bolyard, Johnna J.; Spikell, Mark A.

    Innovations in technology, along with the growing prevalence of the Internet and its increasing availability in classrooms and homes throughout the world, have created a new class of manipulatives, virtual manipulatives. These "virtual manipulatives" offer a new, enhanced approach for teaching and learning mathematics using manipulatives and…

  17. The Virtual Storyteller: story generation by simulation

    NARCIS (Netherlands)

    Swartjes, I.M.T.; Theune, Mariet

    2008-01-01

    The Virtual Storyteller is a multi-agent framework that generates stories based on a concept called emergent narrative. In this paper, we describe the motivation and approach of the Virtual Storyteller, and give an overview of the computational processes involved in the story generation process. We

  18. Virtual nuclear weapons

    Energy Technology Data Exchange (ETDEWEB)

    Pilat, J.F.

    1997-08-01

    The term virtual nuclear weapons proliferation and arsenals, as opposed to actual weapons and arsenals, has entered in recent years the American lexicon of nuclear strategy, arms control, and nonproliferation. While the term seems to have an intuitive appeal, largely due to its cyberspace imagery, its current use is still vague and loose. The author believes, however, that if the term is clearly delineated, it might offer a promising approach to conceptualizing certain current problems of proliferation. The first use is in a reference to an old problem that has resurfaced recently: the problem of growing availability of weapon-usable nuclear materials in civilian nuclear programs along with materials made `excess` to defense needs by current arms reduction and dismantlement. It is argued that the availability of these vast materials, either by declared nuclear-weapon states or by technologically advanced nonweapon states, makes it possible for those states to rapidly assemble and deploy nuclear weapons. The second use has quite a different set of connotations. It is derived conceptually from the imagery of computer-generated reality. In this use, one thinks of virtual proliferation and arsenals not in terms of the physical hardware required to make the bomb but rather in terms of the knowledge/experience required to design, assemble, and deploy the arsenal. Virtual weapons are a physics reality and cannot be ignored in a world where knowledge, experience, materials, and other requirements to make nuclear weapons are widespread, and where dramatic army reductions and, in some cases, disarmament are realities. These concepts are useful in defining a continuum of virtual capabilities, ranging from those at the low end that derive from general technology diffusion and the existence of nuclear energy programs to those at the high end that involve conscious decisions to develop or maintain militarily significant nuclear-weapon capabilities.

  19. Human and Virtual Agents Interacting in the Virtuality Continuum

    NARCIS (Netherlands)

    Nijholt, Antinus; Miyares Bermúdez, E.; Ruiz Miyares, L.

    2006-01-01

    We introduce several of our projects in an overview that makes it possible to compare research approaches on interaction modeling in virtual, mixed-reality and real (physical) environments. For these environments, interaction modeling means multimodal (verbal and nonverbal) interaction modeling

  20. Discovery of novel PPAR ligands by a virtual screening approach based on pharmacophore modeling, 3D shape, and electrostatic similarity screening

    DEFF Research Database (Denmark)

    Markt, Patrick; Petersen, Rasmus K; Flindt, Esben N

    2008-01-01

    Peroxisome proliferator-activated receptors (PPARs) are important targets for drugs used in the treatment of atherosclerosis, dyslipidaemia, obesity, type 2 diabetes, and other diseases caused by abnormal regulation of the glucose and lipid metabolism. We applied a virtual screening workflow base...

  1. A New Approach to Improve Cognition, Muscle Strength, and Postural Balance in Community-Dwelling Elderly with a 3-D Virtual Reality Kayak Program.

    Science.gov (United States)

    Park, Junhyuck; Yim, JongEun

    2016-01-01

    Aging is usually accompanied with deterioration of physical abilities, such as muscular strength, sensory sensitivity, and functional capacity. Recently, intervention methods with virtual reality have been introduced, providing an enjoyable therapy for elderly. The aim of this study was to investigate whether a 3-D virtual reality kayak program could improve the cognitive function, muscle strength, and balance of community-dwelling elderly. Importantly, kayaking involves most of the upper body musculature and needs the balance control. Seventy-two participants were randomly allocated into the kayak program group (n = 36) and the control group (n = 36). The two groups were well matched with respect to general characteristics at baseline. The participants in both groups performed a conventional exercise program for 30 min, and then the 3-D virtual reality kayak program was performed in the kayak program group for 20 min, two times a week for 6 weeks. Cognitive function was measured using the Montreal Cognitive Assessment. Muscle strength was measured using the arm curl and handgrip strength tests. Standing and sitting balance was measured using the Good Balance system. The post-test was performed in the same manner as the pre-test; the overall outcomes such as cognitive function (p kayak program group compared to the control group. We propose that the 3-D virtual reality kayak program is a promising intervention method for improving the cognitive function, muscle strength, and balance of elderly.

  2. Developing a Virtual Rock Deformation Laboratory

    Science.gov (United States)

    Zhu, W.; Ougier-simonin, A.; Lisabeth, H. P.; Banker, J. S.

    2012-12-01

    Experimental rock physics plays an important role in advancing earthquake research. Despite its importance in geophysics, reservoir engineering, waste deposits and energy resources, most geology departments in U.S. universities don't have rock deformation facilities. A virtual deformation laboratory can serve as an efficient tool to help geology students naturally and internationally learn about rock deformation. Working with computer science engineers, we built a virtual deformation laboratory that aims at fostering user interaction to facilitate classroom and outreach teaching and learning. The virtual lab is built to center around a triaxial deformation apparatus in which laboratory measurements of mechanical and transport properties such as stress, axial and radial strains, acoustic emission activities, wave velocities, and permeability are demonstrated. A student user can create her avatar to enter the virtual lab. In the virtual lab, the avatar can browse and choose among various rock samples, determine the testing conditions (pressure, temperature, strain rate, loading paths), then operate the virtual deformation machine to observe how deformation changes physical properties of rocks. Actual experimental results on the mechanical, frictional, sonic, acoustic and transport properties of different rocks at different conditions are compiled. The data acquisition system in the virtual lab is linked to the complied experimental data. Structural and microstructural images of deformed rocks are up-loaded and linked to different deformation tests. The integration of the microstructural image and the deformation data allows the student to visualize how forces reshape the structure of the rock and change the physical properties. The virtual lab is built using the Game Engine. The geological background, outstanding questions related to the geological environment, and physical and mechanical concepts associated with the problem will be illustrated on the web portal. In

  3. Antarctic Ice Velocity Data

    Data.gov (United States)

    National Aeronautics and Space Administration — This compilation of recent ice velocity data of the Antarctic ice sheet is intended for use by the polar scientific community. The data are presented in tabular form...

  4. Using a Virtual History Conference to Teach the Iraq War

    Science.gov (United States)

    Gilley, Bruce

    2013-01-01

    In teaching the causes of the Iraq War, the use of "virtual history" can be employed in a conference setting in which different individuals are assigned to different plausible counterfactuals they use to construct virtual histories. The Iraq War lends itself to the virtual history approach because of the availability of many plausible…

  5. Virtual Sensor for Kinematic Estimation of Flexible Links in Parallel Robots.

    Science.gov (United States)

    Bengoa, Pablo; Zubizarreta, Asier; Cabanes, Itziar; Mancisidor, Aitziber; Pinto, Charles; Mata, Sara

    2017-08-23

    The control of flexible link parallel manipulators is still an open area of research, endpoint trajectory tracking being one of the main challenges in this type of robot. The flexibility and deformations of the limbs make the estimation of the Tool Centre Point (TCP) position a challenging one. Authors have proposed different approaches to estimate this deformation and deduce the location of the TCP. However, most of these approaches require expensive measurement systems or the use of high computational cost integration methods. This work presents a novel approach based on a virtual sensor which can not only precisely estimate the deformation of the flexible links in control applications (less than 2% error), but also its derivatives (less than 6% error in velocity and 13% error in acceleration) according to simulation results. The validity of the proposed Virtual Sensor is tested in a Delta Robot, where the position of the TCP is estimated based on the Virtual Sensor measurements with less than a 0.03% of error in comparison with the flexible approach developed in ADAMS Multibody Software.

  6. Virtual Sensor for Kinematic Estimation of Flexible Links in Parallel Robots

    Directory of Open Access Journals (Sweden)

    Pablo Bengoa

    2017-08-01

    Full Text Available The control of flexible link parallel manipulators is still an open area of research, endpoint trajectory tracking being one of the main challenges in this type of robot. The flexibility and deformations of the limbs make the estimation of the Tool Centre Point (TCP position a challenging one. Authors have proposed different approaches to estimate this deformation and deduce the location of the TCP. However, most of these approaches require expensive measurement systems or the use of high computational cost integration methods. This work presents a novel approach based on a virtual sensor which can not only precisely estimate the deformation of the flexible links in control applications (less than 2% error, but also its derivatives (less than 6% error in velocity and 13% error in acceleration according to simulation results. The validity of the proposed Virtual Sensor is tested in a Delta Robot, where the position of the TCP is estimated based on the Virtual Sensor measurements with less than a 0.03% of error in comparison with the flexible approach developed in ADAMS Multibody Software.

  7. Virtual reality - aesthetic consequences

    OpenAIRE

    Benda, Lubor

    2013-01-01

    In the present work we study aesthetic consequences of virtual reality. Exploring the fringe between fictional and virtual is one of the key goals, that will be achieved through etymologic and technologic definition of both fiction and virtual reality, fictional and virtual worlds. Both fiction and virtual reality will be then studied from aesthetic distance and aesthetic pleasure point of view. At the end, we will see the main difference as well as an common grounds between fiction and virtu...

  8. Virtual Goods Recommendations in Virtual Worlds

    Directory of Open Access Journals (Sweden)

    Kuan-Yu Chen

    2015-01-01

    Full Text Available Virtual worlds (VWs are computer-simulated environments which allow users to create their own virtual character as an avatar. With the rapidly growing user volume in VWs, platform providers launch virtual goods in haste and stampede users to increase sales revenue. However, the rapidity of development incurs virtual unrelated items which will be difficult to remarket. It not only wastes virtual global companies’ intelligence resources, but also makes it difficult for users to find suitable virtual goods fit for their virtual home in daily virtual life. In the VWs, users decorate their houses, visit others’ homes, create families, host parties, and so forth. Users establish their social life circles through these activities. This research proposes a novel virtual goods recommendation method based on these social interactions. The contact strength and contact influence result from interactions with social neighbors and influence users’ buying intention. Our research highlights the importance of social interactions in virtual goods recommendation. The experiment’s data were retrieved from an online VW platform, and the results show that the proposed method, considering social interactions and social life circle, has better performance than existing recommendation methods.

  9. Virtual goods recommendations in virtual worlds.

    Science.gov (United States)

    Chen, Kuan-Yu; Liao, Hsiu-Yu; Chen, Jyun-Hung; Liu, Duen-Ren

    2015-01-01

    Virtual worlds (VWs) are computer-simulated environments which allow users to create their own virtual character as an avatar. With the rapidly growing user volume in VWs, platform providers launch virtual goods in haste and stampede users to increase sales revenue. However, the rapidity of development incurs virtual unrelated items which will be difficult to remarket. It not only wastes virtual global companies' intelligence resources, but also makes it difficult for users to find suitable virtual goods fit for their virtual home in daily virtual life. In the VWs, users decorate their houses, visit others' homes, create families, host parties, and so forth. Users establish their social life circles through these activities. This research proposes a novel virtual goods recommendation method based on these social interactions. The contact strength and contact influence result from interactions with social neighbors and influence users' buying intention. Our research highlights the importance of social interactions in virtual goods recommendation. The experiment's data were retrieved from an online VW platform, and the results show that the proposed method, considering social interactions and social life circle, has better performance than existing recommendation methods.

  10. Stroke Rehabilitation Using Virtual Environments.

    Science.gov (United States)

    Fu, Michael J; Knutson, Jayme S; Chae, John

    2015-11-01

    This review covers the rationale, mechanisms, and availability of commercially available virtual environment-based interventions for stroke rehabilitation. It describes interventions for motor, speech, cognitive, and sensory dysfunction. Also discussed are the important features and mechanisms that allow virtual environments to facilitate motor relearning. A common challenge is the inability to translate success in small trials to efficacy in larger populations. The heterogeneity of stroke pathophysiology has been blamed, and experts advocate for the study of multimodal approaches. Therefore, this article also introduces a framework to help define new therapy combinations that may be necessary to address stroke heterogeneity. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. High-velocity penetrators

    Science.gov (United States)

    Lundgren, Ronald G.

    This paper summarizes the results of studies, coupled with a series of tests, that investigated rigid-body projectiles (penetrators) at high (up to 5500 ft/sec) velocities. Before these studies, it had been hypothesized that a velocity limit would be reached at which increasing the velocity would not commensurately increase depth of penetration into a target. It was further inferred that a given velocity/ penetration depth curve would avalanche into the hydrodynamic regime; that is, increasing the velocity past a certain point would decrease penetration performance. The test series utilized 1/2-in., 3-in., and 5 1/2-in. diameter, ogive-nose steel projectiles and grout and concrete targets. The tests confirmed that penetration depth increased as striking velocity increased to 4000 ft/sec. However, beyond striking velocities of 4000 ft/sec, asymmetric erosion and indentation of the projectile nose from the aggregate caused the projectile trajectories to deviate severely from the target centerline. These trajectory deviations caused the projectile to exit the side of the target, severely bend, break, or exhibit decreased penetration performance, confirming the hypothesis. Clearly, these results were dependent on the specific material and geometric parameters. The projectiles had 3.0 and 4.25 CRH (Caliber-Radius-Head) nose shapes and were heat-treated to R(sub c) 38-40. The grout targets had a maximum aggregate diameter of 3/16 in. and a nominal unconfined compressive strength of 2.5 ksi. The concrete targets had a maximum aggregate diameter of 3/4 in. and unconfined compressive strength of 5.5 ksi.

  12. Kinematic Synthesis for Linkages with Velocity Targets

    Science.gov (United States)

    de-Juan, Ana; Sancibrian, Ramon; García, Pablo; Viadero, Fernando; Iglesias, Miguel; Fernández, Alfonso

    A gradient-based optimization method for designing linkages with velocity targets is described. Two theoretical application cases are established for four-bar linkage. In the first, a constant-velocity module is proposed for a point on the coupler. In the second, the goal is the velocity components. These cases are studied with and without coordination with the input link. The results obtained are compared with another gradient-based approach, and show that the method works efficiently for these types of target.

  13. Virtual PCR

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, S N; Clague, D S; Vandersall, J A; Hon, G; Williams, P L

    2006-02-23

    The polymerase chain reaction (PCR) stands among the keystone technologies for analysis of biological sequence data. PCR is used to amplify DNA, to generate many copies from as little as a single template. This is essential, for example, in processing forensic DNA samples, pathogen detection in clinical or biothreat surveillance applications, and medical genotyping for diagnosis and treatment of disease. It is used in virtually every laboratory doing molecular, cellular, genetic, ecologic, forensic, or medical research. Despite its ubiquity, we lack the precise predictive capability that would enable detailed optimization of PCR reaction dynamics. In this LDRD, we proposed to develop Virtual PCR (VPCR) software, a computational method to model the kinetic, thermodynamic, and biological processes of PCR reactions. Given a successful completion, these tools will allow us to predict both the sequences and concentrations of all species that are amplified during PCR. The ability to answer the following questions will allow us both to optimize the PCR process and interpret the PCR results: What products are amplified when sequence mixtures are present, containing multiple, closely related targets and multiplexed primers, which may hybridize with sequence mismatches? What are the effects of time, temperature, and DNA concentrations on the concentrations of products? A better understanding of these issues will improve the design and interpretation of PCR reactions. The status of the VPCR project after 1.5 years of funding is consistent with the goals of the overall project which was scoped for 3 years of funding. At half way through the projected timeline of the project we have an early beta version of the VPCR code. We have begun investigating means to improve the robustness of the code, performed preliminary experiments to test the code and begun drafting manuscripts for publication. Although an experimental protocol for testing the code was developed, the preliminary

  14. Virtual Software Team Project Management

    OpenAIRE

    Casey, Valentine

    2010-01-01

    Globally distributed information systems development has become a key strategy for large sections of the software industry. This involves outsourcing projects to third parties or offshoring development to divisions in remote locations. A popular approach when implementing these strategies is the establishment of virtual teams. The justification for embarking on this approach is to endeavor to leverage the potential benefits of labor arbitrage available between geographical locations. When ...

  15. Bioinformatics pipelines for targeted resequencing and whole-exome sequencing of human and mouse genomes: a virtual appliance approach for instant deployment.

    Directory of Open Access Journals (Sweden)

    Jason Li

    Full Text Available Targeted resequencing by massively parallel sequencing has become an effective and affordable way to survey small to large portions of the genome for genetic variation. Despite the rapid development in open source software for analysis of such data, the practical implementation of these tools through construction of sequencing analysis pipelines still remains a challenging and laborious activity, and a major hurdle for many small research and clinical laboratories. We developed TREVA (Targeted REsequencing Virtual Appliance, making pre-built pipelines immediately available as a virtual appliance. Based on virtual machine technologies, TREVA is a solution for rapid and efficient deployment of complex bioinformatics pipelines to laboratories of all sizes, enabling reproducible results. The analyses that are supported in TREVA include: somatic and germline single-nucleotide and insertion/deletion variant calling, copy number analysis, and cohort-based analyses such as pathway and significantly mutated genes analyses. TREVA is flexible and easy to use, and can be customised by Linux-based extensions if required. TREVA can also be deployed on the cloud (cloud computing, enabling instant access without investment overheads for additional hardware. TREVA is available at http://bioinformatics.petermac.org/treva/.

  16. Velocities in Solar Pores

    Science.gov (United States)

    Balasubramaniam, K. S.; Keil, S. L.; Smaldone, L. A.

    1996-05-01

    We investigate the three dimensional structure of solar pores and their surroundings using high spatial and spectral resolution data. We present evidence that surface velocities decrease around pores with a corresponding increase in the line-of-sight (LOS) velocities. LOS velocities in pores increase with the strength of the magnetic field. Surface velocities show convergence toward a weak downflow which appear to trace boundaries resembling meso-granular and super granular flows. The observed magnetic fields in the pores appear near these boundaries. We analyze the vertical velocity structure in pores and show that they generally have downflows decreasing exponentially with height, with a scale height of about 90 km. Evidence is also presented for the expanding nature of flux tubes. Finally we describe a phenomenological model for pores. This work was supported by AFOSR Task 2311G3. LAS was partially supported by the Progetto Nazionale Astrofisica e Fisica Cosmica of MURST and Scambi Internazionali of the Universita degli Studi di Napoli Frederico II. National Solar Observatory, NOAO, is operated for the National Science Foundation by AURA, Inc.

  17. Collaborative Educational Systems in the Virtual Environment

    Directory of Open Access Journals (Sweden)

    Cristian CIUREA

    2012-01-01

    Full Text Available The work leads to an original approach to the construction of collaborative systems metrics. The approach is based both on research already conducted by the author, on the experimental results obtained, and the foundation taken from the specific literature. The collaborative systems in knowledge-based economy are formalized and their characteristics are identified. The virtual campus structure is described and a comparison with the classical university is achieved. The architecture of virtual is designed and the categories of agents in virtual campus are analyzed.

  18. Virtual work and shape change in solid mechanics

    CERN Document Server

    Frémond, Michel

    2017-01-01

    This book provides novel insights into two basic subjects in solid mechanics: virtual work and shape change. When we move a solid, the work we expend in moving it is used to modify both its shape and its velocity. This observation leads to the Principle of Virtual Work. Virtual work depends linearly on virtual velocities, which are velocities we may think of. The virtual work of the internal forces accounts for the changes in shape. Engineering provides innumerable examples of shape changes, i.e., deformations, and of velocities of deformation. This book presents examples of usual and unusual shape changes, providing with the Principle of Virtual Work various and sometimes new equations of motion for smooth and non-smooth (i.e., with collisions) motions: systems of disks, systems of balls, classical and non-classical small deformation theories, systems involving volume and surface damage, systems with interactions at a distance (e.g., solids reinforced by fibers), systems involving porosity, beams with third ...

  19. Virtual Trackballs Revisited

    DEFF Research Database (Denmark)

    Henriksen, Knud; Sporring, Jon; Hornbæk, Kasper

    2004-01-01

    Rotation of three-dimensional objects by a two-dimensional mouse is a typical task in computer-aided design, operation simulations, and desktop virtual reality. The most commonly used rotation technique is a virtual trackball surrounding the object and operated by the mouse pointer. This article...... reviews and provides a mathematical foundation for virtual trackballs. The first, but still popular, virtual trackball was described by Chen et al. [CHECK END OF SENTENCE]. We show that the virtual trackball by Chen et al. does not rotate the object along the intended great circular arc on the virtual...... trackball and we give a correction. Another popular virtual trackball is Shoemake's quaternion implementation [CHECK END OF SENTENCE], which we show to be a special case of the virtual trackball by Chen et al.. Shoemake extends the scope of the virtual trackball to the full screen. Unfortunately, Shoemake...

  20. Synthetic Aperture Flow Imaging Using a Dual Stage Beamformer Approach

    DEFF Research Database (Denmark)

    Li, Ye; Jensen, Jørgen Arendt

    2010-01-01

    as virtual sources in the second beamformation algorithm. High resolution image lines are generated by the second stage beamformation. Four emissions in each emission sequence repeat over time. The velocity is estimated by cross correlating high resolution lines which is a function of depth. The cross...... respectively. The parameter study showed that larger interspaces gave an increased standard deviation and the bias. Furthermore more emissions in averaging gave better performance. The performance of the simulation indicates that this dual beamformer approach is able to estimate the flow velocity. Interspaces...... between emissions and number of emission sets in averaging have an influence on the estimation....

  1. Virtual materiality, potentiality and subjctivity

    DEFF Research Database (Denmark)

    Søndergaard, Dorte Marie

    2013-01-01

    How do we conceptualize virtual materiality, in terms of for instance avatars and weapons in computer games, virtual discourse and subjectivity as phenomena intra-acting with real life materiality, discourse and subjectivity in children’s everyday lives? How do we understand the intra-activity of......How do we conceptualize virtual materiality, in terms of for instance avatars and weapons in computer games, virtual discourse and subjectivity as phenomena intra-acting with real life materiality, discourse and subjectivity in children’s everyday lives? How do we understand the intra......-activity of such elements in children’s night dreams? These are some of the questions discussed in this text. I bring together Karen Barad’s agential realism and Giorgi Agamben’s concept of potentiality to enable and refine an analytical approach to real-virtual enactments, thereby questioning the potentialities of gaming......, of movies and of dreams as they enter intra-activities in the comprehensive set of apparatuses that enact child agency, subjectivity and relational practices. The analyses and conceptual refinements are based on empirical cases involving interviews with and observations among 8-14 year old children....

  2. Balancing virtual land imports by a shift in the diet. Using a land balance approach to assess the sustainability of food consumption. Germany as an example.

    Science.gov (United States)

    Meier, Toni; Christen, Olaf; Semler, Edmund; Jahreis, Gerhard; Voget-Kleschin, Lieske; Schrode, Alexander; Artmann, Martina

    2014-03-01

    Nutrition is considered as one of the main drivers of global environmental change. Dietary patterns in particular, embedded in the international trade of foods and other biomass based commodities, determine the dimension of beneficial or harmful environmental impacts of the agri-food sector - both domestically and abroad. In this study we analysed different dietary scenarios from a virtual land flow perspective, based on representative consumption data for Germany in the years 2006 and 1985-89. Further we identified the consumer groups that would have to adapt most to balance Germany's virtual land import and analysed the impact reduced food wastage. For the study, official data sets concerning production, trade and consumption were used. We derived land use data from environmentally extended input-output data sets and FAO statistics. The conversion of agricultural raw products to consumed commodities is based on official processing and composition data. Subgroup-specific intake data from the last representative National Nutrition Survey in Germany were used. We analysed 42 commodities, aggregated into 23 product groups, seven land use types and six nutrition scenarios. The results show that in the baseline scenario the average nutrition in the year 2006 leads to a virtual land import of 707m(2)p(-1)a(-1), which represents 30% of the total nutrition-induced land demand of 2365m(2)p(-1)a(-1). On the other hand, the German agri-food sector exports virtual land, in the form of commodities, equivalent to 262m(2)p(-1)a(-1). In this paper we calculate that the resulting net import of virtual land could be balanced by way of a shift to an officially recommended diet and a reduction in the consumption of stimulants (cocoa, coffee, green/black tea, wine). A shift to an ovo-lacto-vegetarian or vegan diet would even lead to a positive virtual land balance (even with maintained consumption of stimulants). Moreover, we demonstrate that a shift in the average diet profile could

  3. Chat, pizarra virtual, aulas modulares virtuales

    OpenAIRE

    Demo, Juan Pablo; Painefilu, Jaime Paul; Ferreira Szpiniak, Ariel; Zorzán, Fabio

    2014-01-01

    En el presente artículo se estudian distintas herramientas sincrónicas y asincrónicas que pueden ser incorporadas dentro de un aula virtual. En particular, se analizan desde el punto de vista de integrarlas a un Entorno Virtual de Enseñanza y Aprendizaje (EVEA) específico. Los componentes seleccionados tienen que ver con comunicación por texto de forma on-line (chat), pizarras virtuales, y organización de aulas virtuales por unidades o módulos que permitan a cada alumno seguir su propia secue...

  4. Velocity pump reaction turbine

    Science.gov (United States)

    House, P.A.

    An expanding hydraulic/two-phase velocity pump reaction turbine including a dual concentric rotor configuration with an inter-rotor annular flow channel in which the inner rotor is mechanically driven by the outer rotor. In another embodiment, the inner rotor is immobilized and provided with gas recovery ports on its outer surface by means of which gas in solution may be recovered. This velocity pump reaction turbine configuration is capable of potential energy conversion efficiencies of up to 70%, and is particularly suited for geothermal applications.

  5. Portable Userspace Virtual Filesystem Switch

    Directory of Open Access Journals (Sweden)

    Łukasz Faber

    2013-01-01

    Full Text Available Multiple different filesystems — including disk-based, network, distributed, abstract — arean integral part of every operating system. They are usually written as kernel modules and abstracted to the user via a virtual filesystem switch. In this paper we analyse the feasibility of reimplementing the virtual filesystem switch as a userspace daemon and applicability of this approach in real-life usage. Such reimplementation will require a way to virtualise processes behaviour related to filesystem operations. The problem is non-trivial, as we assume limited capabilities of the VFS switch implemented in userspace. We present a layered architecture comprising of a monitoring process, the VFS abstraction and real filesystem implementations. All working in userspace. Then, we evaluate this solution in four areas: portability, feasibility, usability and performance. Our results demonstrate possible gains in using the userspace-based approach with monolithic kernels, but also underline problems that are encountered in this approach.

  6. The Prescribed Velocity Method

    DEFF Research Database (Denmark)

    Nielsen, Peter Vilhelm

    The- velocity level in a room ventilated by jet ventilation is strongly influenced by the supply conditions. The momentum flow in the supply jets controls the air movement in the room and, therefore, it is very important that the inlet conditions and the numerical method can generate a satisfactory...

  7. Movement velocity vs. strength training

    Directory of Open Access Journals (Sweden)

    Mário C. Marques

    2017-06-01

    practice in strength training, but increasing evidence (Sanborn et al., 2000; Folland et al., 2002; Izquierdo et al., 2006; Drinkwater et al., 2007 shows that training to repetition failure does not necessarily produce better strength gains and that may even be counterproductive by inducing excessive fatigue, mechanical and metabolic strain (Fry, 2004. In fact, fatigue associated with training to failure not only significantly reduces the force that a muscle can generate, but also the nervous system’s ability to voluntarily activate the muscles (Häkkinen, 1993. Consequently, this approach, besides being very tiring and having shown no advantage over other lower effort types of training, it is unrealistic because it is practically impossible to know exactly how many repetitions can be done with a given absolute load without any initial reference. In addition, if in the first set the subject has completed the maximum number of repetitions, it will be very difficult or even impossible to perform properly the same number of reps in the following sets. Movement velocity is another variable which could be of great interest for monitoring exercise intensity, but surprisingly it has been vaguely mentioned in most studies to date. The importance that monitoring movement velocity for strength training programming have already been noticed in 1991 (González-Badillo, 1991. More recently, González-Badillo and Sánchez-Medina (2010, 2011 studied this hypothesis and confirmed that movement velocity provides as a determinant of the level of effort during resistance training as well as an indicator of the degree of fatigue. Unfortunately, the lack of use of this variable is likely because until recently it was not possible to accurately measure velocity in isoinertial strength training exercises/movements.  Indeed, most research that has addressed movement velocity in strength training was basically conducted using isokinetic apparatus which, unfortunately, is not an ideal or common

  8. From Cognitive Capability to Social Reform? Shifting Perceptions of Learning in Immersive Virtual Worlds

    Science.gov (United States)

    Savin-Baden, Maggi

    2008-01-01

    Learning in immersive virtual worlds (simulations and virtual worlds such as Second Life) could become a central learning approach in many curricula, but the socio-political impact of virtual world learning on higher education remains under-researched. Much of the recent research into learning in immersive virtual worlds centres around games and…

  9. OPTIMAL SURGICAL MANAGEMENT OF HIGH VELOCITY POSTERIOR TIBIAL PLATEAU FRACTURE SUBLUXATIONS (DUPARC, REVISED CLASSIFICATION, GROUP – V: POSTERO - MEDIAL FRACTURE BY DIRECT, DORSAL APPROACH – A CHANGING TREND: A PROSPECTIVE STUDY

    Directory of Open Access Journals (Sweden)

    Pardhasaradhi

    2015-10-01

    series of 15 patients with complex tibial plateau injuries with associated posterior shear fractures. MATERIALS AND METHODS : This prospective study included 15 cases of patients with mean age of 30 years ( Age range 20 to 40 yr who sustained high velocity posterior tibial plateau fracture - subluxations with or without associated Bicondylar fractures ( Duparc, revised classification, Group – V: Postero - medial fracture and its associations. Surgical management includes by direct, dorsal approach and stabilisation with buttress plating and or also postero medial and or antero lateral approach as needed. The patients were followed up at six week, three month, six month and one year postoperatively and assessed using Oxford Knee Score and Lyshom Score. RESULTS:The mean OKS score was 40 (range 36 to 44 at the end of one year. The main clinical measures were early post - operative non weight bearing ROM, post - operative complication & functional outcome. The time to full weight bearing, t he rate of post - operative complications & functional outcome was significantly better as evident by over 94 % showing good to excellent OKS and Lyshom scores. CONCLUSION : Fractures of the postero - medial tibial plateau are challenging to treat, owing to the ir complexity and unfamiliar surgical approach. Several recent anatomic and biomechanical studies have shown that a locked plate placed from the lateral side of the proximal tibia does not capture and stabilise a typical posteromedial fragment. A direct po sterior (Medial Gastrocnemius or posterior medial approach for these unstable posterior medial tibial plateau subluxations (which are otherwise irreducible by conventional approaches and antiglide plate are usually needed to reduce the fractures anatomic ally, achieving absolute stability and mobilise early NWB, ROM of the knee joint to optimize the functional outcomes and minimise the complications, without the need for revision surgery

  10. Poster: Virtual reality interaction using mobile devices

    KAUST Repository

    Aseeri, Sahar A.

    2013-03-01

    In this work we aim to implement and evaluate alternative approaches for interacting with virtual environments on mobile devices for navigation, object selection and manipulation. Interaction with objects in virtual worlds using traditional input such as current state-of-the-art devices is often difficult and could diminish the immersion and sense of presence when it comes to 3D virtual environment tasks. We have developed new methods to perform different kinds of interactions using a mobile device (e.g. a smartphone) both as input device, performing selection and manipulation of objects, and as output device, utilizing the screen as an extra view (virtual camera or information display). Our hypothesis is that interaction via mobile devices facilitates simple tasks like the ones described within immersive virtual reality systems. We present here our initial implementation and result. © 2013 IEEE.

  11. A Virtual Class Calculus

    DEFF Research Database (Denmark)

    Ernst, Erik; Ostermann, Klaus; Cook, William Randall

    2006-01-01

    Virtual classes are class-valued attributes of objects. Like virtual methods, virtual classes are defined in an object's class and may be redefined within subclasses. They resemble inner classes, which are also defined within a class, but virtual classes are accessed through object instances......, not as static components of a class. When used as types, virtual classes depend upon object identity - each object instance introduces a new family of virtual class types. Virtual classes support large scale program composition techniques, including higher-order hierarchies and family polymorphism. The original...... definition of virtual classes in BETA left open the question of static type safety, since some type errors were not caught until runtime. Later the languages Caesar and gbeta have used a more strict static analysis in order to ensure static type safety. However, the existence of a sound, statically typed...

  12. Organization Virtual or Networked?

    OpenAIRE

    Rūta Tamošiūnaitė

    2013-01-01

    Purpose—to present distinction between “virtual organization” and “networked organization”; giving their definitions.Design/methodology/approach—review of previous researches, systemic analyses of their findings and synthesis of distinctive characteristics of ”virtual organization” and “networked organization.”Findings—the main result of the research is key diverse features separating ”virtual organization” and ”networked organization.” Definitions of “virtual organization” and “networked org...

  13. Virtual reality exposure therapy

    OpenAIRE

    Rothbaum, BO; Hodges, L; Kooper, R

    1997-01-01

    It has been proposed that virtual reality (VR) exposure may be an alternative to standard in vivo exposure. Virtual reality integrates real-time computer graphics, body tracking devices, visual displays, and other sensory input devices to immerse a participant in a computer- generated virtual environment. Virtual reality exposure is potentially an efficient and cost-effective treatment of anxiety disorders. VR exposure therapy reduced the fear of heights in the first control...

  14. Server virtualization solutions

    OpenAIRE

    Lodziņš, Gunārs Ernests

    2007-01-01

    Currently in the information technology sector that is responsible for a server infrastructure is a huge development in the field of server virtualization on x86 computer architecture. As a prerequisite for such a virtualization development is growth in server productivity and underutilization of available computing power. Several companies in the market are working on two virtualization architectures – hypervizor and hosting. In this paper several of virtualization products that use host...

  15. A new estimator for vector velocity estimation [medical ultrasonics

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt

    2001-01-01

    A new estimator for determining the two-dimensional velocity vector using a pulsed ultrasound field is derived. The estimator uses a transversely modulated ultrasound field for probing the moving medium under investigation. A modified autocorrelation approach is used in the velocity estimation....... The new estimator automatically compensates for the axial velocity when determining the transverse velocity. The estimation is optimized by using a lag different from one in the estimation process, and noise artifacts are reduced by averaging RF samples. Further, compensation for the axial velocity can...... be introduced, and the velocity estimation is done at a fixed depth in tissue to reduce the influence of a spatial velocity spread. Examples for different velocity vectors and field conditions are shown using both simple and more complex field simulations. A relative accuracy of 10.1% is obtained...

  16. Wave propagation and group velocity

    CERN Document Server

    Brillouin, Léon

    1960-01-01

    Wave Propagation and Group Velocity contains papers on group velocity which were published during the First World War and are missing in many libraries. It introduces three different definitions of velocities: the group velocity of Lord Rayleigh, the signal velocity of Sommerfeld, and the velocity of energy transfer, which yields the rate of energy flow through a continuous wave and is strongly related to the characteristic impedance. These three velocities are identical for nonabsorbing media, but they differ considerably in an absorption band. Some examples are discussed in the last chapter

  17. Acceleration of objects to high velocity by electromagnetic forces

    Science.gov (United States)

    Post, Richard F

    2017-02-28

    Two exemplary approaches to the acceleration of projectiles are provided. Both approaches can utilize concepts associated with the Inductrack maglev system. Either of them provides an effective means of accelerating multi-kilogram projectiles to velocities of several kilometers per second, using launchers of order 10 meters in length, thus enabling the acceleration of projectiles to high velocities by electromagnetic forces.

  18. VIRTUAL LEADERSHIP AT DISTANCE EDUCATION TEAMS

    Directory of Open Access Journals (Sweden)

    Meltem KUSCU

    2016-07-01

    Full Text Available Globalization being one of the most popular terms of recent years is considered as a factor changing the operation styles of the companies. Companies and universities opened up to the world with the globalization and as a result of it, they had the opportunity of being a world brand. Now, some companies have affiliated companies in almost every country. Well, if we think about time and place difference how do these companies lead the affiliated companies in various locations of the world? This question resulted in the new leadership approach, virtual leadership. The process of distance learning beginning with newspaper advertisement appears as virtual learning now. A number of companies and universities provide distance learning classes and in-service training in virtual platform via Internet. These trainings provided independently from time and space are conducted in a country and worldwide sometimes. If we consider individuals in different time and environments as virtual teams, dealing with these virtual teams is the duty of virtual leader. The purpose of this study is to examine virtual leadership perception of distance learning teams. Three trivets are in question for distance learning teams. The first one is the academicians lecturing the second one is the students and the third one is coordinator and technical support team. Perceptions of virtual leader of the said three groups were examined individually in this study.

  19. The concept of strong and weak virtual reality

    OpenAIRE

    Lisewski, A. M.

    2003-01-01

    We approach the virtual reality phenomenon by studying its relationship to set theory, and we investigate the case where this is done using the wellfoundedness property of sets. Our hypothesis is that non-wellfounded sets (hypersets) give rise to a different quality of virtual reality than do familiar wellfounded sets. We initially provide an alternative approach to virtual reality based on Sommerhoff's idea of first and second order self-awareness; both categories of self-awareness are consi...

  20. Virtual autopsy in hanging.

    Science.gov (United States)

    Polacco, Matteo; D'Alessio, Pasquale; Ausania, Francesco; Zobel, Bruno; Pascali, Vincenzo Lorenzo; d'Aloja, Ernesto; Miscusi, Massimo; De-Giorgio, Fabio

    2013-06-01

    The aim of the study was to compare postmortem computed tomographic (CT) imaging findings from a case of hanging with the autopsy findings. The CT showed a good match with autopsy findings especially for bone, soft tissue, and spinal injuries. The CT images of the injuries of the neck obtained by CT scan clearly showed the ligature mark, the hemorrhagic suffusion in the soft tissue (thickening of derma) and in the muscles (sternocleidomastoid) of the neck. Furthermore, CT 3-dimensional reconstruction showed brain edema, fracture of the left posterior horn of the hyoid bone, and a grade 1 retrolisthesis of C5 on C6. This last finding was not detected by autopsy because of the anterior approach that is frequently used in necropsy technique. Nevertheless, the CT virtual autopsy did not show vascular findings (like Amussat mark) because a barium mixture was not injected in the body.

  1. Virtual reality for stroke rehabilitation.

    Science.gov (United States)

    Laver, Kate E; Lange, Belinda; George, Stacey; Deutsch, Judith E; Saposnik, Gustavo; Crotty, Maria

    2017-11-20

    Virtual reality and interactive video gaming have emerged as recent treatment approaches in stroke rehabilitation with commercial gaming consoles in particular, being rapidly adopted in clinical settings. This is an update of a Cochrane Review published first in 2011 and then again in 2015. Primary objective: to determine the efficacy of virtual reality compared with an alternative intervention or no intervention on upper limb function and activity.Secondary objectives: to determine the efficacy of virtual reality compared with an alternative intervention or no intervention on: gait and balance, global motor function, cognitive function, activity limitation, participation restriction, quality of life, and adverse events. We searched the Cochrane Stroke Group Trials Register (April 2017), CENTRAL, MEDLINE, Embase, and seven additional databases. We also searched trials registries and reference lists. Randomised and quasi-randomised trials of virtual reality ("an advanced form of human-computer interface that allows the user to 'interact' with and become 'immersed' in a computer-generated environment in a naturalistic fashion") in adults after stroke. The primary outcome of interest was upper limb function and activity. Secondary outcomes included gait and balance and global motor function. Two review authors independently selected trials based on pre-defined inclusion criteria, extracted data, and assessed risk of bias. A third review author moderated disagreements when required. The review authors contacted investigators to obtain missing information. We included 72 trials that involved 2470 participants. This review includes 35 new studies in addition to the studies included in the previous version of this review. Study sample sizes were generally small and interventions varied in terms of both the goals of treatment and the virtual reality devices used. The risk of bias present in many studies was unclear due to poor reporting. Thus, while there are a large

  2. High-Velocity Clouds

    CERN Document Server

    Woerden, Hugo; Schwarz, Ulrich J; Boer, Klaas S

    2005-01-01

    This book contains 17 chapters reviewing our knowledge of the high-velocity clouds (HVCs) as of 2004, bringing this together in one place for the first time. Each of the many different aspects of HVC research is addressed by one of the experts in that subfield. These include a historical overview of HVC research and analyses of the structure and kinematics of HVCs. Separate chapters address the intermediate-velocity clouds, the Magellanic Stream, and neutral hydrogen HVCs discovered in external galaxies. Reviews are presented of the Ha emission and of optical and UV absorption-line studies, followed by discussions of the hot Galactic Halo and of the interactions between HVCs and their surroundings. Four chapters summarize the ideas about the origin of the high-velocity gas, with detailed discussions of connections between HVCs and the Galactic Fountain, tidally-stripped material, and remnants of the Milky Way's formation. A chapter outlining what we do not know completes the book. The book comes at a time whe...

  3. Building Productivity in Virtual Project Teams

    Directory of Open Access Journals (Sweden)

    Bill Hamersly

    2015-04-01

    Full Text Available The steady increase in project failure rates is leaving businesses searching for better integration techniques to virtualize their project environments. Through virtualization, organizations may have positive impacts on communities across geographical boundaries and resource constraints. The focus of this phenomenological study was to explore, via the experiences of successful project management practitioners, best practice strategies for integrating virtual project teams through data analysis. The conceptual framework included von Bertalanffy’s general systems theory, decomposition model of business process and project management frameworks, and the recomposition approach. Twenty-two senior project managers with more than 5 years of experience managing virtual project environments participated in semistructured telephone interviews. The van Kaam process employing normalization and bracketing approaches in data analysis resulted in the emergence of 34 thematic categories. The 10 most common themes culminated in the identification of strategies relevant for virtual project teams. The major themes pertained to 3 broad areas: (a structure that accommodates skills and technology for virtual team success, (b governance leading to efficient virtual project team management, and (c collaboration practices across diverse environments. This study involved the exploration of the experiences of the participants. Using the van Kaam method for normalization of the data and clustering like experiences into thematic statements, the study provided a plethora of new information concentrated on 10 themes that emerged.

  4. Virtual Reality Interaction Using Mobile Devices

    KAUST Repository

    Aseeri, Sahar A.

    2013-07-01

    With the use of an immersive display system such as CAVE system, the user is able to realize a 3D immersive virtual environment realistically. However, interacting with virtual worlds in CAVE systems using traditional input devices to perform easy operations such as manipulation, object selection, and navigation is often difficult. This difficulty could diminish the immersion and sense of presence when it comes to 3D virtual environment tasks. Our research aims to implement and evaluate alternative approaches of interaction with immersive virtual environments on mobile devices for manipulation and object selection tasks. As many researchers have noted, using a mobile device as an interaction device has a number of advantages, including built-in display, built-in control, and touch screen facility. These advantages facilitate simple tasks within immersive virtual environments. This research proposes new methods using mobile devices like Smart-phones to perform di↵erent kinds of interactions both as an input device, (e.g. performing selection and manipulation of objects) and as an output device (e.g. utilizing the screen as an extra view for a virtual camera or information display). Moreover, we developed a prototype system to demonstrate and informally evaluate these methods. The research conclusion suggests using mobile devices as a 3D-controller. This will be a more intuitive approach to interact within the virtual environment.

  5. Development of a Virtual Reality Exposure Tool as Psychological Preparation for Elective Pediatric Day Care Surgery: Methodological Approach for a Randomized Controlled Trial.

    Science.gov (United States)

    Eijlers, Robin; Legerstee, Jeroen S; Dierckx, Bram; Staals, Lonneke M; Berghmans, Johan; van der Schroeff, Marc P; Wijnen, Rene Mh; Utens, Elisabeth Mwj

    2017-09-11

    Preoperative anxiety in children is highly prevalent and is associated with adverse outcomes. Existing psychosocial interventions to reduce preoperative anxiety are often aimed at distraction and are of limited efficacy. Gradual exposure is a far more effective way to reduce anxiety. Virtual reality (VR) provides a unique opportunity to gradually expose children to all aspects of the operating theater. The aims of our study are (1) to develop a virtual reality exposure (VRE) tool to prepare children psychologically for surgery; and (2) to examine the efficacy of the VRE tool in a randomized controlled trial (RCT), in which VRE will be compared to care as usual (CAU). The VRE tool is highly realistic and resembles the operating room environment accurately. With this tool, children will not only be able to explore the operating room environment, but also get accustomed to general anesthesia procedures. The PREoperative Virtual reality Intervention to Enhance Wellbeing (PREVIEW) study will be conducted. In this single-blinded RCT, 200 consecutive patients (aged 4 to 12 years) undergoing elective day care surgery for dental, oral, or ear-nose-throat problems, will be randomly allocated to the preoperative VRE intervention or CAU. The primary outcome is change in child state anxiety level between baseline and induction of anesthesia. Secondary outcome measures include child's postoperative anxiety, emergence delirium, postoperative pain, use of analgesics, health care use, and pre- and postoperative parental anxiety. The VRE tool has been developed. Participant recruitment began March 2017 and is expected to be completed by September 2018. To our knowledge, this is the first RCT evaluating the effect of a VRE tool to prepare children for surgery. The VRE intervention is expected to significantly diminish preoperative anxiety, postoperative pain, and the use of postoperative analgesics in pediatric patients. The tool could create a less stressful experience for both

  6. Virtualization A Manager's Guide

    CERN Document Server

    Kusnetzky, Dan

    2011-01-01

    What exactly is virtualization? As this concise book explains, virtualization is a smorgasbord of technologies that offer organizations many advantages, whether you're managing extremely large stores of rapidly changing data, scaling out an application, or harnessing huge amounts of computational power. With this guide, you get an overview of the five main types of virtualization technology, along with information on security, management, and modern use cases. Topics include: Access virtualization-Allows access to any application from any deviceApplication virtualization-Enables applications

  7. Policy needs and options for a common approach towards modelling and simulation of human physiology and diseases with a focus on the virtual physiological human.

    Science.gov (United States)

    Viceconti, Marco; McCulloch, Andrew D

    2011-01-01

    Life is the result of an intricate systemic interaction between many processes occurring at radically different spatial and temporal scales. Every day, worldwide biomedical research and clinical practice produce a huge amount of information on such processes. However, this information being highly fragmented, its integration is largely left to the human actors who find this task increasingly and ever more demanding in a context where the information available continues to increase exponentially. Investments in the Virtual Physiological Human (VPH) research are largely motivated by the need for integration in healthcare. As all health information becomes digital, the complexity of health care will continue to evolve, translating into an ever increasing pressure which will result from a growing demand in parallel to limited budgets. Hence, the best way to achieve the dream of personalised, preventive, and participative medicine at sustainable costs will be through the integration of all available data, information and knowledge.

  8. COLLABORATION SYSTEM IN VIRTUAL ORGANIZATION

    Directory of Open Access Journals (Sweden)

    ADINA CRETAN

    2011-04-01

    Full Text Available The purpose of this work is to provide a collaboration support for small and medium enterprises which cannot or do not want to fulfill a major contract alone. In that case, in order to better meet a higher external demand, the managers are willing to subcontract parts of their contracts even to competitors. This approach is illustrated by a business-to-business interaction, being proposed a sample scenario where partners are autonomous gas stations grouped in a virtual organization.

  9. The Virtual Water Transactions Promote Environmental Justice?

    OpenAIRE

    Corte, Thaís Dalla; Corte, Tiago Dalla

    2016-01-01

    As natural water, virtual water is essential for the dynamics of life. It, that correspond to the total volume of fresh water used in the production process in one place and that was incorporated into the final goods, is a calculation that can contribute to human access to water be assured in sufficient quantities for a dignified life. Therefore, the objective of this research is, through the hypothetical-deductive method of approach, evaluate virtual water transfers from the perspective of e...

  10. A memory model for autonomous virtual humans

    OpenAIRE

    Peters, Christopher; O'SULLIVAN, CAROL ANN

    2002-01-01

    PUBLISHED A memory model based on ?stage theory?, the dominant view of memory from the field of cognitive psychology, is presented for application to autonomous virtual humans. The virtual human senses external stimuli through a synthetic vision system. The vision system incorporates multiple modes of vision in order to accommodate a perceptual attention approach. The memory model is used to store perceived and attended object data at different stages in a filtering process....

  11. Virtual reality and planetary exploration

    Science.gov (United States)

    McGreevy, Michael W.

    Exploring planetary environments is central to NASA's missions and goals. A new computing technology called Virtual Reality has much to offer in support of planetary exploration. This technology augments and extends human presence within computer-generated and remote spatial environments. Historically, NASA has been a leader in many of the fundamental concepts and technologies that comprise Virtual Reality. Indeed, Ames Research Center has a central role in the development of this rapidly emerging approach to using computers. This ground breaking work has inspired researchers in academia, industry, and the military. Further, NASA's leadership in this technology has spun off new businesses, has caught the attention of the international business community, and has generated several years of positive international media coverage. In the future, Virtual Reality technology will enable greatly improved human-machine interactions for more productive planetary surface exploration. Perhaps more importantly, Virtual Reality technology will democratize the experience of planetary exploration and thereby broaden understanding of, and support for, this historic enterprise.

  12. Cavity Enhanced Velocity Modulation Spectroscopy

    Science.gov (United States)

    Siller, Brian; Mills, Andrew; Porambo, Michael; McCall, Benjamin

    2010-11-01

    Over the past several decades, velocity modulation spectroscopy has been used to study dozens of molecular ions of astronomical importance. This technique has been so productive because it provides the advantage of ion-neutral discrimination, which is critically important when interfering neutral molecules are many orders of magnitude more abundant, and when combined with heterodyne techniques, its sensitivity can approach the shot noise limit. Traditionally, velocity modulation experiments have utilized unidirectional multipass White cells to achieve up to about 8 passes through a positive column discharge cell. But by positioning the cell within an optical cavity, it is possible to obtain an effective path length orders of magnitude longer than was previously possible. We have demonstrated this novel technique using a Ti:Sapp laser in the near-IR to observe rovibronic transitions of N2+. By demodulating at twice the modulation frequency, 2nd derivative-like lineshapes are observed for ions that are velocity-modulated, while Gaussian lineshapes are observed for excited neutral that are concentration-modulated. The signals for N2+ and N2+* have been observed to be 78° out of phase with one another, so ion-neutral discrimination is retained. And due to the laser power enhancement and geometry of the optical cavity, Doppler-free saturation spectroscopy is now possible. Observed Lamb dips have widths of 50 MHz, and when combined with calibration by an optical frequency comb, this allows for determination of line centers to within 1 MHz. In our original demonstration of this technique, our sensitivity was limited by noise in the laser-cavity lock. Since then, we have integrated Noise Immune Cavity Enhanced Optical Heterodyne Molecular Spectroscopy (NICE-OHMS) by adding sidebands to the laser at an exact multiple of the cavity free spectral range, and demodulating at the sideband frequency before sending the signal to a lock-in amplifier for demodulating at twice the

  13. Cochrane review: virtual reality for stroke rehabilitation.

    Science.gov (United States)

    Laver, K; George, S; Thomas, S; Deutsch, J E; Crotty, M

    2012-09-01

    Virtual reality and interactive video gaming are innovative therapy approaches in the field of stroke rehabilitation. The primary objective of this review was to determine the effectiveness of virtual reality on motor function after stroke. The impact on secondary outcomes including activities of daily living was also assessed. Randomised and quasi-randomised controlled trials that compared virtual reality with an alternative or no intervention were included in the review. The authors searched the Cochrane Stroke Group Trials Register, the Cochrane Central Register of Controlled Trials, electronic databases, trial registers, reference lists, Dissertation Abstracts, conference proceedings and contacted key researchers and virtual reality manufacturers. Search results were independently examined by two review authors to identify studies meeting the inclusion criteria. Nineteen studies with a total of 565 participants were included in the review. Variation in intervention approaches and outcome data collected limited the extent to which studies could be compared. Virtual reality was found to be significantly more effective than conventional therapy in improving upper limb function (standardised mean difference, SMD) 0.53, 95% confidence intervals [CI] 0.25 to 0.81)) based on seven studies, and activities of daily living (ADL) function (SMD 0.81, 95% CI 0.39 to 1.22) based on three studies. No statistically significant effects were found for grip strength (based on two studies) or gait speed (based on three studies). Virtual reality appears to be a promising approach however, further studies are required to confirm these findings.

  14. P1138Cardiac shear wave velocity in healthy individuals.

    Science.gov (United States)

    Strachinaru, M; Geleijnse, M L; Bosch, J G; De Jong, N; Van Der Steen, Afw; Van Dalen, B M; Vos, H J

    2016-12-01

    The closure of the valves generates shear waves in the heart walls. The propagation velocity of shear waves relates to stiffness. This could potentially be used to estimate the stiffness of the myocardium, with huge potential implications in pathologies characterized by a deterioration of the diastolic properties of the left ventricle. In an earlier phantom study we already validated shear wave tracking with a clinical ultrasound system in cardiac mode. In this study we aimed to measure the shear waves velocity in normal individuals. 12 healthy volunteers, mean age=37±10, 33% females, were investigated using a clinical scanner (Philips iE33), equipped with a S5-1 probe, using a clinical tissue Doppler (TDI) application. ECG and phonocardiogram (PCG) were synchronously recorded. We achieved a TDI frame rate of >500Hz by carefully tuning normal system settings. Data were processed offline in Philips Qlab 8 to extract tissue velocity along a virtual M-mode line in the basal third of the interventricular septum, in parasternal long axis view. This tissue velocity showed a propagating wave pattern after closure of the valves. The slope of the wave front velocity in a space-time panel was measured to obtain the shear wave propagation velocity. The velocity of the shear waves induced by the closure of the mitral valve (1st heart sound) and aortic valve (2nd heart sound) was averaged over 4 heartbeats for every subject. Shear waves were visible after each closure of the heart valves, synchronous to the heart sounds. The figure shows one heart cycle of a subject, with the mean velocity along a virtual M-mode line in the upper panel, synchronous to the ECG signal (green line) and phonocardiogram (yellow line) in the lower panel. The slope of the shear waves is marked with dotted lines and the onset of the heart sounds with white lines. In our healthy volunteer group the mean velocity of the shear wave induced by mitral valve closure was 4.8±0.7m/s, standard error of 0.14 m

  15. Exploitation of the Virtual Worlds in Tourism and Tourism Education

    Directory of Open Access Journals (Sweden)

    Zejda Pavel

    2016-12-01

    Full Text Available Academics perceive a great potential of virtual worlds in various areas, including tourism and education. Efforts adapting the virtual worlds in practice are, however, still marginal. There is no clear definition of the virtual world. Therefore the author of this article attempts to provide one. The paper also focuses on the barriers of a wider exploitation of the virtual worlds and discusses the principles that might help to increase their potential in tourism area. One of the principles – gamification – favours a wider adaptation of the virtual worlds in tourism. Applying gamification principles provides visitors with some unique experiences while serving as a powerful marketing tool for institutions. The benefits of implementing tourism education activities based on cooperative principles set in an immersive environment of the virtual worlds are depicted afterwards. Finally, this paper includes successful case studies, which show advantages and drawbacks of some approaches in exploiting the virtual worlds in tourism and tourism education.

  16. Virtual Classroom: A Boon to Learners

    Science.gov (United States)

    Ananthasayanam, R.; Rajathi, Thangam; Tamilselvi, B.

    2009-01-01

    Demands for a more personalized approach to education as well as flexibility have spurred learners to seek alternatives to the traditional approach. As a result of technological advantages in society, the options for learning in and outside the classroom have broadened tremendously. The great option is "Virtual classroom". A virtual…

  17. The Apparent Velocity and Acceleration of Relativistically Moving Objects

    CERN Document Server

    Berlet, Austen; Chishtie, Farrukh; Houde, Martin

    2011-01-01

    Although special relativity limits the actual velocity of a particle to $c$, the velocity of light, the observed velocity need not be the same as the actual velocity as the observer is only aware of the position of a particle at the time in the past when it emits the detected signal. We consider the apparent speed and acceleration of a particle in two cases, one when the particle is moving with a constant speed and the other when it is moving with a constant acceleration. One curious feature of our results is that in both cases, if the actual velocity of the particle approaches $c$, then the apparent velocity approaches infinity when it is moving toward the observer and $c/2$ when it is moving away from the observer.

  18. Shoulder Kinematics and Spatial Pattern of Trapezius Electromyographic Activity in Real and Virtual Environments

    Science.gov (United States)

    Samani, Afshin; Pontonnier, Charles; Dumont, Georges; Madeleine, Pascal

    2015-01-01

    The design of an industrial workstation tends to include ergonomic assessment steps based on a digital mock-up and a virtual reality setup. Lack of interaction and system fidelity is often reported as a main issue in such virtual reality applications. This limitation is a crucial issue as thorough ergonomic analysis is required for an investigation of the biomechanics. In the current study, we investigated the biomechanical responses of the shoulder joint in a simulated assembly task for comparison with the biomechanical responses in virtual environments. Sixteen male healthy novice subjects performed the task on three different platforms: real (RE), virtual (VE), and virtual environment with force feedback (VEF) with low and high precision demands. The subjects repeated the task 12 times (i.e., 12 cycles). High density electromyography from the upper trapezius and rotation angles of the shoulder joint were recorded and split into the cycles. The angular trajectories and velocity profiles of the shoulder joint angles over a cycle were computed in 3D. The inter-subject similarity in terms of normalized mutual information on kinematics and electromyography was investigated. Compared with RE the task in VE and VEF was characterized by lower kinematic maxima. The inter-subject similarity in RE compared with intra-subject similarity across the platforms was lower in terms of movement trajectories and greater in terms of trapezius muscle activation. The precision demand resulted in lower inter- and intra-subject similarity across platforms. The proposed approach identifies biomechanical differences in the shoulder joint in both VE and VEF compared with the RE platform, but these differences are less marked in VE mostly due to technical limitations of co-localizing the force feedback system in the VEF platform. PMID:25768123

  19. Shoulder kinematics and spatial pattern of trapezius electromyographic activity in real and virtual environments.

    Directory of Open Access Journals (Sweden)

    Afshin Samani

    Full Text Available The design of an industrial workstation tends to include ergonomic assessment steps based on a digital mock-up and a virtual reality setup. Lack of interaction and system fidelity is often reported as a main issue in such virtual reality applications. This limitation is a crucial issue as thorough ergonomic analysis is required for an investigation of the biomechanics. In the current study, we investigated the biomechanical responses of the shoulder joint in a simulated assembly task for comparison with the biomechanical responses in virtual environments. Sixteen male healthy novice subjects performed the task on three different platforms: real (RE, virtual (VE, and virtual environment with force feedback (VEF with low and high precision demands. The subjects repeated the task 12 times (i.e., 12 cycles. High density electromyography from the upper trapezius and rotation angles of the shoulder joint were recorded and split into the cycles. The angular trajectories and velocity profiles of the shoulder joint angles over a cycle were computed in 3D. The inter-subject similarity in terms of normalized mutual information on kinematics and electromyography was investigated. Compared with RE the task in VE and VEF was characterized by lower kinematic maxima. The inter-subject similarity in RE compared with intra-subject similarity across the platforms was lower in terms of movement trajectories and greater in terms of trapezius muscle activation. The precision demand resulted in lower inter- and intra-subject similarity across platforms. The proposed approach identifies biomechanical differences in the shoulder joint in both VE and VEF compared with the RE platform, but these differences are less marked in VE mostly due to technical limitations of co-localizing the force feedback system in the VEF platform.

  20. Examples of Vector Velocity Imaging

    DEFF Research Database (Denmark)

    Hansen, Peter M.; Pedersen, Mads M.; Hansen, Kristoffer L.

    2011-01-01

    To measure blood flow velocity in vessels with conventional ultrasound, the velocity is estimated along the direction of the emitted ultrasound wave. It is therefore impossible to obtain accurate information on blood flow velocity and direction, when the angle between blood flow and ultrasound wa...

  1. Virtual reality for engineering

    CERN Document Server

    De Gennaro, Silvano; CERN. Geneva

    1996-01-01

    Virtual Reality for Engineers. Virtual Reality is a very powerful visualization technique for 3D data, which can bring enormous benefits to engineering design. CAD models can be exported to a VR application and used as "Virtual Prototypes". Virtual Prototypes are an ideal replacement for wooden models as they can be generated automatically from most CAD products. They are totally reliable, they can be updated in a matter of minutes, and they allow designers to explore them from inside, on a one-to-one scale and using a 3D-stereo vision. Navigation can be performed using a number of instinctive tools, such as joysticks, spaceballs, VR helmets and 3D mice. The lectures will cover today's Virtual Reality products and methods, and describe how to transform CAD models into Virtual Prototypes. A "hands on" VR experience featuring the LHC detectors models can be organized for people interested.

  2. Learning by doing virtually.

    Science.gov (United States)

    von Sternberg, N; Bartsch, M S; Petersik, A; Wiltfang, J; Sibbersen, W; Grindel, T; Tiede, U; Warnke, P H; Heiland, M; Russo, P A J; Terheyden, H; Pohlenz, P; Springer, I N

    2007-05-01

    Selective reduction of bone without collateral damage (nerves, teeth) is essential in apicectomy. To test whether skills acquired on a virtual apicectomy simulator (VOXEL-MAN system with integrated force-feedback) are transferable from virtual to physical reality, two groups of trainees were compared. Group 1 received computer-based virtual surgical training before performing an apicectomy in a pig cadaver model. The probability of preserving vital neighboring structures was improved significantly, i.e. six-fold, after virtual surgical training (P<0.001). The average volume of the bony defects created by the trainees of Group 2 (mean: 0.47 ml) was significantly (P<0.001) larger than by the trainees of Group 1 (mean: 0.25 ml). Most importantly, the ability to objectively self-assess performance was significantly improved after virtual training. Training with a virtual apicectomy simulator appears to be effective, and the skills acquired are transferable to physical reality.

  3. Materials space of solid-state electrolytes: unraveling chemical composition-structure-ionic conductivity relationships in garnet-type metal oxides using cheminformatics virtual screening approaches.

    Science.gov (United States)

    Kireeva, Natalia; Pervov, Vladislav S

    2017-08-09

    The organic electrolytes of most current commercial rechargeable Li-ion batteries (LiBs) are flammable, toxic, and have limited electrochemical energy windows. All-solid-state battery technology promises improved safety, cycling performance, electrochemical stability, and possibility of device miniaturization and enables a number of breakthrough technologies towards the development of new high power and energy density microbatteries for electronics with low processing cost, solid oxide fuel cells, electrochromic devices, etc. Currently, rational materials design is attracting significant attention, which has resulted in a strong demand for methodologies that can accelerate the design of materials with tailored properties; cheminformatics can be considered as an efficient tool in this respect. This study was focused on several aspects: (i) identification of the parameters responsible for high Li-ion conductivity in garnet structured oxides; (ii) development of quantitative models to elucidate composition-structure-Li ionic conductivity relationships, taking into account the experimental details of sample preparation; (iii) circumscription of the materials space of solid garnet-type electrolytes, which is attractive for virtual screening. Several candidate compounds have been recommended for synthesis as potential solid state electrolyte materials.

  4. Virtual Campus Hub technology

    DEFF Research Database (Denmark)

    Vercoulen, Frank; Badger, Merete; Monaco, Lucio

    This deliverable briefly describes which technological components have been delivered for the Virtual Campus Hub and how they can be used. A detailed discussion of the technical details of the components, how they were realized and how they fit the VCH concept can be found in deliverables D5.......4. Virtual Campus Hub Technology Evaluation Report and D6.7 The Virtual Campus Hub Concept....

  5. Virtual Environments for Training

    National Research Council Canada - National Science Library

    Stiles, R

    1998-01-01

    .... Progress on productization of the VET Training Studio software includes increased robustness for Vista virtual environment display and interaction services, a new capability to use the STEVE visual...

  6. Spacebody actual virtual

    DEFF Research Database (Denmark)

    Kjøbek, Jytte; Sørensen, Gert

    2005-01-01

    DVD som indeholder filmen 'spacebody actual virtual' . Videoen er værkdelen af forskningsprojektet Arkitektur og skikkelse, spacebody actual virtual. Foruden DVD'en indeholder projektet et reflekterende materiale på hjemmesiden www.spacebody.dk Fysisk medie: DVD......DVD som indeholder filmen 'spacebody actual virtual' . Videoen er værkdelen af forskningsprojektet Arkitektur og skikkelse, spacebody actual virtual. Foruden DVD'en indeholder projektet et reflekterende materiale på hjemmesiden www.spacebody.dk Fysisk medie: DVD...

  7. Virtual Training Devices Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Virtual Training Devices (VTD) Laboratory at the Life Cycle Software Engineering Center, Picatinny Arsenal, provides a software testing and support environment...

  8. Virtual Reality Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Performs basic and applied research in interactive 3D computer graphics, including visual analytics, virtual environments, and augmented reality (AR). The...

  9. A "virtually minimal" visuo-haptic training of attention in severe traumatic brain injury

    National Research Council Canada - National Science Library

    Dvorkin, Assaf Y; Ramaiya, Milan; Larson, Eric B; Zollman, Felise S; Hsu, Nancy; Pacini, Sonia; Shah, Amit; Patton, James L

    2013-01-01

    .... We designed a "virtually minimal" approach using robot-rendered haptics in a virtual environment to train severely injured inpatients in the early stages of recovery to sustain attention to a visuo-motor task...

  10. Velocity Controller for a Class of Vehicles

    Directory of Open Access Journals (Sweden)

    Herman Przemyslaw

    2017-02-01

    Full Text Available This paper addresses the problem of velocity tracking control for various fully-actuated robotic vehicles. The presented method, which is based on transformation of equations of motion allows one to use, in the control gain matrix, the dynamical couplings existing in the system. Consequently, the dynamics of the vehicle is incorporated into the control process what leads to fast velocity error convergence. The stability of the system under the controller is derived based on Lyapunov argument. Moreover, the robustness of the proposed controller is shown too. The general approach is valid for 6 DOF models as well as other reduced models of vehicles. Simulation results on a 6 DOF indoor airship validate the described velocity tracking methodology.

  11. Towards Culturally-Aware Virtual Agent Systems

    DEFF Research Database (Denmark)

    Endrass, Birgit; André, Elisabeth; Rehm, Matthias

    2010-01-01

    in a game-like environment in a more interesting way than for example learning with a textbook. The authors support the idea that virtual agents are a great opportunity for teaching cultural awareness. Realizing this, the concept of culture needs to be translated into computational models and the advantages...... of different systems using virtual agents need to be considered. Therefore, the authors reflect in this chapter on how virtual agents can help to learn about culture, scan definitions of culture from the social sciences, give an overview on how multiagent systems developed over time and classify the state...... of the art that integrates culture in multiagent systems. In addition, an approach of simulating culture-specific behavior using such a multiagent system is introduced and future trends in enculturating virtual agent systems are outlined....

  12. Modelling of two-phase flow based on separation of the flow according to velocity

    Energy Technology Data Exchange (ETDEWEB)

    Narumo, T. [VTT Energy, Espoo (Finland). Nuclear Energy

    1997-12-31

    The thesis concentrates on the development work of a physical one-dimensional two-fluid model that is based on Separation of the Flow According to Velocity (SFAV). The conventional way to model one-dimensional two-phase flow is to derive conservation equations for mass, momentum and energy over the regions occupied by the phases. In the SFAV approach, the two-phase mixture is divided into two subflows, with as distinct average velocities as possible, and momentum conservation equations are derived over their domains. Mass and energy conservation are treated equally with the conventional model because they are distributed very accurately according to the phases, but momentum fluctuations follow better the flow velocity. Submodels for non-uniform transverse profile of velocity and density, slip between the phases within each subflow and turbulence between the subflows have been derived. The model system is hyperbolic in any sensible flow conditions over the whole range of void fraction. Thus, it can be solved with accurate numerical methods utilizing the characteristics. The characteristics agree well with the used experimental data on two-phase flow wave phenomena Furthermore, the characteristics of the SFAV model are as well in accordance with their physical counterparts as of the best virtual-mass models that are typically optimized for special flow regimes like bubbly flow. The SFAV model has proved to be applicable in describing two-phase flow physically correctly because both the dynamics and steady-state behaviour of the model has been considered and found to agree well with experimental data This makes the SFAV model especially suitable for the calculation of fast transients, taking place in versatile form e.g. in nuclear reactors. 45 refs. The thesis includes also five previous publications by author.

  13. Virtual reality simulators and training in laparoscopic surgery.

    Science.gov (United States)

    Yiannakopoulou, Eugenia; Nikiteas, Nikolaos; Perrea, Despina; Tsigris, Christos

    2015-01-01

    Virtual reality simulators provide basic skills training without supervision in a controlled environment, free of pressure of operating on patients. Skills obtained through virtual reality simulation training can be transferred on the operating room. However, relative evidence is limited with data available only for basic surgical skills and for laparoscopic cholecystectomy. No data exist on the effect of virtual reality simulation on performance on advanced surgical procedures. Evidence suggests that performance on virtual reality simulators reliably distinguishes experienced from novice surgeons Limited available data suggest that independent approach on virtual reality simulation training is not different from proctored approach. The effect of virtual reality simulators training on acquisition of basic surgical skills does not seem to be different from the effect the physical simulators. Limited data exist on the effect of virtual reality simulation training on the acquisition of visual spatial perception and stress coping skills. Undoubtedly, virtual reality simulation training provides an alternative means of improving performance in laparoscopic surgery. However, future research efforts should focus on the effect of virtual reality simulation on performance in the context of advanced surgical procedure, on standardization of training, on the possibility of synergistic effect of virtual reality simulation training combined with mental training, on personalized training. Copyright © 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

  14. An improved estimation and focusing scheme for vector velocity estimation

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Munk, Peter

    1999-01-01

    The full blood velocity vector must be estimated in medical ultrasound to give a correct depiction of the blood flow. This can be done by introducing a transversely oscillating pulse-echo ultrasound field, which makes the received signal influenced by a transverse motion. Such an approach...... was suggested in [1]. Here the conventional autocorrelation approach was used for estimating the transverse velocity and a compensation for the axial motion was necessary in the estimation procedure. This paper introduces a new estimator for determining the two-dimensional velocity vector and a new dynamic...... beamforming method. A modified autocorrelation approach employing fourth order moments of the input data is used for velocity estimation. The new estimator calculates the axial and lateral velocity component independently of each other. The estimation is optimized for differences in axial and lateral...

  15. Measurement of velocity and velocity derivatives based on pattern tracking in 3D LIF images

    Energy Technology Data Exchange (ETDEWEB)

    Deusch, S.; Merava, H.; Rys, P. [Swiss Federal Inst. of Technol., Zurich (Switzerland). Dept. of Chem. Eng.; Dracos, T. [Swiss Federal Institute of Technology, Untergasse 14, 8126 Zumikon (Switzerland)

    2000-10-01

    Pattern tracking in consecutive 3D LIF images based on least squares matching (LSM) of grey levels has been developed recently for velocity and velocity gradient measurements. The shortcomings of this method are clearly shown. The present article presents an improvement on this method by introducing a local multi-patch (LMP) technique through the LSM approach. The method is validated using the flow field of a turbulent channel flow obtained by direct numerical simulation (DNS) and a synthetic image with grey-level patterns. The results show that LMP matching allows the determination of the velocity and the velocity gradient fields with high accuracy including the second derivatives. Measurements of a round non-buoyant jet are presented which demonstrate the good performance of the method when applied under laboratory conditions. This method can also be applied on two-dimensional images provided that the flow is strictly two-dimensional. (orig.)

  16. Measurement of velocity and velocity derivatives based on pattern tracking in 3D LIF images

    Science.gov (United States)

    Deusch, S.; Merava, H.; Dracos, T.; Rys, P.

    Pattern tracking in consecutive 3D LIF images based on least squares matching (LSM) of grey levels has been developed recently for velocity and velocity gradient measurements. The shortcomings of this method are clearly shown. The present article presents an improvement on this method by introducing a local multi-patch (LMP) technique through the LSM approach. The method is validated using the flow field of a turbulent channel flow obtained by direct numerical simulation (DNS) and a synthetic image with grey-level patterns. The results show that LMP matching allows the determination of the velocity and the velocity gradient fields with high accuracy including the second derivatives. Measurements of a round non-buoyant jet are presented which demonstrate the good performance of the method when applied under laboratory conditions. This method can also be applied on two-dimensional images provided that the flow is strictly two-dimensional.

  17. Seismic Velocity Gradients Across the Transition Zone

    Science.gov (United States)

    Escalante, C.; Cammarano, F.; de Koker, N.; Piazzoni, A.; Wang, Y.; Marone, F.; Dalton, C.; Romanowicz, B.

    2006-12-01

    One-D elastic velocity models derived from mineral physics do a notoriously poor job at predicting the velocity gradients in the upper mantle transition zone, as well as some other features of models derived from seismological data. During the 2006 CIDER summer program, we computed Vs and Vp velocity profiles in the upper mantle based on three different mineral physics approaches: two approaches based on the minimization of Gibbs Free Energy (Stixrude and Lithgow-Bertelloni, 2005; Piazzoni et al., 2006) and one obtained by using experimentally determined phase diagrams (Weidner and Wang, 1998). The profiles were compared by assuming a vertical temperature profile and two end-member compositional models, the pyrolite model of Ringwood (1979) and the piclogite model of Anderson and Bass (1984). The predicted seismic profiles, which are significantly different from each other, primarily due to different choices of properties of single minerals and their extrapolation with temperature, are tested against a global dataset of P and S travel times and spheroidal and toroidal normal mode eigenfrequencies. All the models derived using a potential temperature of 1600K predict seismic velocities that are too slow in the upper mantle, suggesting the need to use a colder geotherm. The velocity gradient in the transition zone is somewhat better for piclogite than for pyrolite, possibly indicating the need to increase Ca content. The presence of stagnant slabs in the transition zone is a possible explanation for the need for 1) colder temperature and 2) increased Ca content. Future improvements in seismic profiles obtained from mineral physics will arise from better knowledge of elastic properties of upper mantle constituents and aggregates at high temperature and pressure, a better understanding of differences between thermodynamic models, and possibly the effect of water through and on Q. High resolution seismic constraints on velocity jumps at 400 and 660 km also need to be

  18. LoGV: Low-overhead GPGPU Virtualization

    OpenAIRE

    Gottschlag, Mathias; Hillenbrand, Marius; Kehne, Jens; Stoess, Jan; Bellosa, Frank

    2013-01-01

    Over the last few years, running high performance computing applications in the cloud has become feasible. At the same time, GPGPUs are delivering unprecedented performance for HPC applications. Cloud providers thus face the challenge to integrate GPGPUs into their virtualized platforms, which has proven difficult for current virtualization stacks. In this paper, we present LoGV, an approach to virtualize GPGPUs by leveraging protection mechanisms already present in modern hardware. LoGV enab...

  19. Virtual machine initiated operations logic for resource management

    OpenAIRE

    Lartey, Nii Apleh

    2009-01-01

    Master i nettverks- og systemadministrasjon This thesis takes a look at an alternative approach to resource management using virtual- ization. The paper makes an attempt at looking at some administrative issues that arise due to current designs of virtualization management especially in multi-tenant virtual hosting environments and possibility of taking advantage of different kinds of offers from different providers through automated operations logic driven management. The a...

  20. Paradoxes in virtual team knowledge communication and trust building

    OpenAIRE

    Petersen, Nils Braad

    2012-01-01

    This thesis proposal presents paradoxes within current trust and knowledge management literatures as a lens for understanding challenges in virtual teams working across organisational and geographic boundaries. By exposing contradictions within current virtual team research, the author proposes a need for a different, multi-level, multi-theoretical approach to virtual team research in order to overcome the paradoxes. A moderate constructionist research position building on Critical Realism is...

  1. Virtual reality for stroke rehabilitation.

    Science.gov (United States)

    Laver, Kate E; George, Stacey; Thomas, Susie; Deutsch, Judith E; Crotty, Maria

    2015-02-12

    Virtual reality and interactive video gaming have emerged as recent treatment approaches in stroke rehabilitation. In particular, commercial gaming consoles have been rapidly adopted in clinical settings. This is an update of a Cochrane Review published in 2011. To determine the efficacy of virtual reality compared with an alternative intervention or no intervention on upper limb function and activity. To determine the efficacy of virtual reality compared with an alternative intervention or no intervention on: gait and balance activity, global motor function, cognitive function, activity limitation, participation restriction and quality of life, voxels or regions of interest identified via imaging, and adverse events. Additionally, we aimed to comment on the feasibility of virtual reality for use with stroke patients by reporting on patient eligibility criteria and recruitment. We searched the Cochrane Stroke Group Trials Register (October 2013), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2013, Issue 11), MEDLINE (1950 to November 2013), EMBASE (1980 to November 2013) and seven additional databases. We also searched trials registries and reference lists. Randomised and quasi-randomised trials of virtual reality ("an advanced form of human-computer interface that allows the user to 'interact' with and become 'immersed' in a computer-generated environment in a naturalistic fashion") in adults after stroke. The primary outcome of interest was upper limb function and activity. Secondary outcomes included gait and balance function and activity, and global motor function. Two review authors independently selected trials based on pre-defined inclusion criteria, extracted data and assessed risk of bias. A third review author moderated disagreements when required. The authors contacted investigators to obtain missing information. We included 37 trials that involved 1019 participants. Study sample sizes were generally small and interventions

  2. OVERLAPPING VIRTUAL CADASTRAL DOCUMENTATION

    Directory of Open Access Journals (Sweden)

    Madalina - Cristina Marian

    2013-12-01

    Full Text Available Two cadastrale plans of buildings, can overlap virtual. Overlap is highlighted when digital reception. According to Law no. 7/1996 as amended and supplemented, to solve these problems is by updating the database graphs, the repositioning. This paper addresses the issue of overlapping virtual cadastre in the history of the period 1999-2012.

  3. Virtual School Counseling

    Science.gov (United States)

    Osborn, Debra S.; Peterson, Gary W.; Hale, Rebecca R.

    2015-01-01

    The advent of virtual schools opens doors to opportunity for delivery of student services via the Internet. Through the use of structured interviews with four practicing Florida virtual school counselors, and a follow-up survey, the authors examined the experiences and reflections of school counselors who are employed full time in a statewide…

  4. Virtual Pediatric Hospital

    Science.gov (United States)

    ... Thoracopaedia - An Imaging Encyclopedia of Pediatric Thoracic Disease Virtual Pediatric Hospital is the Apprentice's Assistant™ Last revised ... pediatric resources: GeneralPediatrics.com | PediatricEducation.org | SearchingPediatrics.com Virtual Pediatric Hospital is curated by Donna M. D' ...

  5. Virtual Seminar Room

    DEFF Research Database (Denmark)

    Forchhammer, Søren Otto; Fosgerau, Anders; Hansen, Peter Søren Kirk

    1999-01-01

    The initial design considerations and research goals for an ATM network based virtual seminar room with 5 sites are presented.......The initial design considerations and research goals for an ATM network based virtual seminar room with 5 sites are presented....

  6. Virtual Company and Modelbank

    DEFF Research Database (Denmark)

    Thorsteinsson, Uffe

    1996-01-01

    Ansøgning til Socrates programmet vedr. Tematisk netværk inden for området Virtual Company and Modelbank......Ansøgning til Socrates programmet vedr. Tematisk netværk inden for området Virtual Company and Modelbank...

  7. Virtual Trauma Team

    NARCIS (Netherlands)

    Jones, Valerie M.; Bults, Richard G.A.

    2001-01-01

    The clinical motivation for Virtual Trauma Team is to improve quality of care in trauma care in the vital first "golden hour" where correct intervention can greatly improve likely health outcome. The motivation for Virtual Homecare Team is to improve quality of life and independence for patients by

  8. Virtual Reality in Psychology

    Science.gov (United States)

    Foreman, Nigel

    2009-01-01

    The benefits of using virtual environments (VEs) in psychology arise from the fact that movements in virtual space, and accompanying perceptual changes, are treated by the brain in much the same way as those in equivalent real space. The research benefits of using VEs, in areas of psychology such as spatial learning and cognition, include…

  9. A Virtual Good Idea

    Science.gov (United States)

    Bolch, Matt

    2009-01-01

    School districts across the country have always had to do more with less. Funding goes only so far, leaving administrators and IT staff to find innovative ways to save money while maintaining a high level of academic quality. Creating virtual servers accomplishes both tasks, district technology personnel say. Virtual environments not only allow…

  10. 10 Myths of Virtualization

    Science.gov (United States)

    Schaffhauser, Dian

    2012-01-01

    Half of servers in higher ed are virtualized. But that number's not high enough for Link Alander, interim vice chancellor and CIO at the Lone Star College System (Texas). He aspires to see 100 percent of the system's infrastructure requirements delivered as IT services from its own virtualized data centers or other cloud-based operators. Back in…

  11. Taxation of virtual currency

    NARCIS (Netherlands)

    Bal, Aleksandra Marta

    2014-01-01

    The Information Age has created a new concept of money – virtual currencies existing solely in the cyberspace in the form of intangible computer code. The most prominent virtual currency scheme, Bitcoin, grabbed the public attention as its value skyrocketed at the beginning of 2012. Whereas Bitcoin

  12. Virtual reality musical instruments

    DEFF Research Database (Denmark)

    Serafin, Stefania; Erkut, Cumhur; Kojs, Juraj

    2016-01-01

    The rapid development and availability of low cost technologies has created a wide interest in virtual reality (VR), but how to design and evaluate multisensory interactions in VR remains as a challenge. In this paper, we focus on virtual reality musical instruments, present an overview of our...

  13. Designing Virtual Learning Environments

    DEFF Research Database (Denmark)

    Veirum, Niels Einar

    2003-01-01

    The main objective of this working paper is to present a conceptual model for media integrated communication in virtual learning environments. The model for media integrated communication is very simple and identifies the necessary building blocks for virtual place making in a synthesis of methods...

  14. The issue of virtual teams

    OpenAIRE

    Fleiberková, Šárka

    2012-01-01

    The aim of this diploma thesis is the introduction of teamwork and virtual teams. The theoretical part of this work describes the birth of teamwork, its definition, properties, advantages and disadvantages. Next part of diploma thesis is dedicated to the virtual team. It describes the difference among virtual and traditional team, definition and characteristics of virtual team as well as tools that are used in virtual team. The second, practical, unit is focused on virtual teams at universiti...

  15. A virtual reality scenario for all seasons: the virtual classroom.

    Science.gov (United States)

    Rizzo, Albert A; Bowerly, Todd; Buckwalter, J Galen; Klimchuk, Dean; Mitura, Roman; Parsons, Thomas D

    2006-01-01

    Treatment and rehabilitation of the cognitive, psychological, and motor sequelae of central nervous system dysfunction often relies on assessment instruments to inform diagnosis and to track changes in clinical status. Typically, these assessments employ paper-and-pencil psychometrics, hands-on analog/computer tests, and rating of behavior within the context of real-world functional environments. Virtual reality offers the option to produce and distribute identical "standard" simulation environments in which performance can be measured and rehabilitated. Within such digital scenarios, normative data can be accumulated for performance comparisons needed for assessment/diagnosis and for treatment/rehabilitation purposes. In this manner, reusable archetypic virtual environments constructed for one purpose can also be applied for applications addressing other clinical targets. This article will provide a review of such a retooling approach using a virtual classroom simulation that was originally developed as a controlled stimulus environment in which attention processes could be systematically assessed in children with attention-deficit/hyperactivity disorder. This system is now being applied to other clinical targets including the development of tests that address other cognitive functions, eye movement under distraction conditions, social anxiety disorder, and the creation of an earthquake safety training application for children with developmental and learning disabilities.

  16. Development of an optimal velocity selection method with velocity obstacle

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Geuk; Oh, Jun Ho [KAIST, Daejeon (Korea, Republic of)

    2015-08-15

    The Velocity obstacle (VO) method is one of the most well-known methods for local path planning, allowing consideration of dynamic obstacles and unexpected obstacles. Typical VO methods separate a velocity map into a collision area and a collision-free area. A robot can avoid collisions by selecting its velocity from within the collision-free area. However, if there are numerous obstacles near a robot, the robot will have very few velocity candidates. In this paper, a method for choosing optimal velocity components using the concept of pass-time and vertical clearance is proposed for the efficient movement of a robot. The pass-time is the time required for a robot to pass by an obstacle. By generating a latticized available velocity map for a robot, each velocity component can be evaluated using a cost function that considers the pass-time and other aspects. From the output of the cost function, even a velocity component that will cause a collision in the future can be chosen as a final velocity if the pass-time is sufficiently long enough.

  17. VEM: Virtual Enterprise Methodology

    DEFF Research Database (Denmark)

    Tølle, Martin; Vesterager, Johan

    2003-01-01

    This chapter presents a virtual enterprise methodology (VEM) that outlines activities to consider when setting up and managing virtual enterprises (VEs). As a methodology the VEM helps companies to ask the right questions when preparing for and setting up an enterprise network, which works as a b...... as a breeding ground for setting up VEs. The VEM applies the Virtual Enterprise Reference Architecture (VERA) as an underlying structure. Both VEM and VERA are developed as a part of the GLOBEMEN project.......This chapter presents a virtual enterprise methodology (VEM) that outlines activities to consider when setting up and managing virtual enterprises (VEs). As a methodology the VEM helps companies to ask the right questions when preparing for and setting up an enterprise network, which works...

  18. Interactive Virtual Cinematography

    DEFF Research Database (Denmark)

    Burelli, Paolo

    control of the camera by the player increases the complexity of the interaction and reduces the designer's control on game storytelling. A completely designer-driven camera releases the player from the burden of controlling the point of view, but might generate undesired camera behaviours. Furthermore......A virtual camera represents the point-of-view of the player through which she perceives the game world and gets feedback on her actions. Thus, the virtual camera plays a vital role in 3D computer games and aects player experience and enjoyability in games. Interactive virtual cinematography...... is the process of visualising the content of a virtual environment by positioning and animating the virtual camera in the context of interactive applications such as a computer game. Camera placement and animation in games are usually directly controlled by the player or statically predened by designers. Direct...

  19. Virtual Project Teams

    DEFF Research Database (Denmark)

    Bjørn, Pernille

    in virtual project teams whose members are spread across various geographical locations. The aim is to understand the specific factors, conditions and challenges underpinning such situations. This thesis describes, analyses and discusses three in-depth empirical studies on the practices and use of groupware...... technology in six real-life virtual teams, two in industry and four in education, applying interpretative research and action research methods. Two main lines of investigation are pursued: the first involves an examination of the organisational issues related to groupware adaptation in virtual project teams......, while the second looks at the social context and practices of virtual project teams. Two of the key findings are 1) that the process of groupware adaptation by virtual project teams can be viewed as a process of expanding and aligning the technological frames of the participants, which includes mutual...

  20. L’acustica dell’orecchio esterno: un approccio a modelli strutturali misti per display uditivi virtuali - The external ear acoustics: a mixed structural modeling approach in virtual auditory displays

    Directory of Open Access Journals (Sweden)

    Michele Geronazzo

    2015-07-01

    Full Text Available Gli effetti acustici rilevanti per la percezione verticale del suono, quali le riflessioni sui contorni del padiglione auricolare e le risonanze all'interno delle cavità dell'orecchio, possono venir isolati e modellati da una combinazione di filtri sintetici e contributi misurati acusticamente. Questo approccio prende il nome di modellazione strutturale mista (MSM e viene utilizzato, più in generale, per descrivere la Head-Related Transfer Function (HRTF, che cattura gli effetti di testa, busto e orecchie dell'ascoltatore. Questo articolo impiega la MSM nella realizzazione di display uditivi capaci di adattarsi all'antropometria dell'ascoltatore per la resa della dimensione verticale del suono. ---------- The most important acoustic effects involved in vertical spatial sound perception, i.e. reflections on pinna contours and resonances inside the ear cavities, are isolated and modeled separately. The combination of such components that can be chosen to include either synthetic or measured components, is formalized in the Mixed Structural Modeling (MSM approach which describes, more in general, the Head-Related Transfer Functions (HRTFs capturing effects of head, torso, and external ear of the listener. This paper employs the MSM approach aiming at building personalized virtual auditory displays (VADs able to adapt to listener anthropometry and to convey vertical localization cues.

  1. Imagining virtual community: online media fandom and the construction of virtual collectivity

    OpenAIRE

    DeDominicis, Kali Lou

    2016-01-01

    This thesis uses ethnographic research into online media fandom, focusing on self-reflexive analytical documents that fans call meta, to investigate longstanding questions about the nature of virtual community. It argues that virtual documents should be seen as complete and complex interactions in their original form and as social contexts in their own right, and presents a new approach to ethnographic methodology and ethics suited to working in this context. Fans have incorpor...

  2. STARE velocities: 2. Evening westward electron flow

    Directory of Open Access Journals (Sweden)

    M. Uspensky

    2004-04-01

    Full Text Available Four evening events and one morning event of joint EISCAT/STARE observations during ~22h are considered and the differences between observed STARE line-of-sight (l-o-s velocities and EISCAT electron drift velocities projected onto the STARE beams are studied. We demonstrate that the double-pulse technique, which is currently in use in the STARE routine data handling, typically underestimates the true phase velocity as inferred from the multi-pulse STARE data. We show that the STARE velocities are persistently smaller (1.5–2 times than the EISCAT velocities, even for the multi-pulse data. The effect seems to be more pronounced in the evening sector when the Finland radar observes at large flow angles. We evaluate the performance of the ion-acoustic approach (IAA, Nielsen and Schlegel, 1985 and the off-orthogonal fluid approach (OOFA, Uspensky et al., 2003 techniques to predict the true electron drift velocity for the base event of 12 February 1999. The IAA technique predicts the convection reasonably well for enhanced flows of >~1000m/s, but not so well for slower ones. By considering the EISCAT N(h profiles, we derive the effective aspect angle and effective altitude of backscatter, and use this information for application of the OOFA technique. We demonstrate that the OOFA predictions for the base event are superior over the IAA predictions and thus, we confirm that OOFA predicts the electron velocities reasonably well in the evening sector, in addition to the morning sector, as concluded by Uspensky et al. (2003. To check how "robust" the OOFA model is and how successful it is for convection estimates without the EISCAT support, we analysed three additional evening events and one additional morning event for which information on N(h profiles was intentionally ignored. By accepting the mean STARE/EISCAT velocity ratio of 0.55 and the mean azimuth rotation of 9° (derived for the basic event, we show that the OOFA performs

  3. Virtual microscopy in virtual tumor banking

    NARCIS (Netherlands)

    Isabelle, M.; Teodorovic, I.; Oosterhuis, J. W.; Riegman, P. H. J.; Passioukov, A.; Lejeune, S.; Therasse, P.; Dinjens, W. N. M.; Lam, K. H.; Oomen, M. H. A.; Spatz, A.; Ratcliffe, C.; Knox, K.; Mager, R.; Kerr, D.; Pezzella, F.; van Damme, B.; van de Vijver, M.; van Boven, H.; Morente, M. M.; Alonso, S.; Kerjaschki, D.; Pammer, J.; López-Guerrero, J. A.; Llombart-Bosch, A.; Carbone, A.; Gloghini, A.; van Veen, E. B.

    2006-01-01

    Many systems have already been designed and successfully used for sharing histology images over large distances, without transfer of the original glass slides. Rapid evolution was seen when digital images could be transferred over the Internet. Nowadays, sophisticated virtual microscope systems can

  4. Contract Driven Creation and Operation of Virtual Enterprises

    NARCIS (Netherlands)

    Hoffner, Yigal; Field, Simon; Grefen, P.W.P.J.; Ludwig, Heiko

    2001-01-01

    This paper examines the support needed for dynamically creating and managing contract-driven virtual enterprises. Our approach to virtual enterprises views contracts as the central theme that runs throughout the enterprises' life cycle and touches upon all major aspects thereof. A Contract Framework

  5. Interactive creation of virtual worlds using procedural sketching

    NARCIS (Netherlands)

    Smelik, R.M.; Tutenel, T.; Kraker, K.J. de; Bidarra, R.

    2010-01-01

    Procedural modelling is an attractive alternative to cut down the costs of manual content creation for virtual worlds. We discuss our declarative modelling approach to the creation of 3D virtual worlds, which integrates a variety of procedural techniques in order to enable a non-specialist user to

  6. Scenario-Based Spoken Interaction with Virtual Agents

    Science.gov (United States)

    Morton, Hazel; Jack, Mervyn A.

    2005-01-01

    This paper describes a CALL approach which integrates software for speaker independent continuous speech recognition with embodied virtual agents and virtual worlds to create an immersive environment in which learners can converse in the target language in contextualised scenarios. The result is a self-access learning package: SPELL (Spoken…

  7. Putting the PLE into PLD: Virtual Professional Learning and Development

    Science.gov (United States)

    Owen, Hazel

    2014-01-01

    The range of affordances that a virtual environment offers can provide opportunities for more formal Professional Learning and Development (PLD) that has flexibility of choice, time and approach for educators. It was this potential that inspired the design of the Virtual Professional Learning and Development (VPLD) program that was instigated in…

  8. Experiences with a synchronous virtual classroom in distance education

    NARCIS (Netherlands)

    Koppelman, Hermannus; Vranken, H.

    2008-01-01

    Modern technology offers the tools for having synchronous virtual classes. This paper reports about experiences of such a class in the context of distance education. The paper focuses on the tool as well as on the pedagogy. It outlines the pedagogical approach of the virtual class, which is an

  9. Security of OS-level virtualization technologies: Technical report

    OpenAIRE

    Reshetova, Elena; Karhunen, Janne; Nyman, Thomas; Asokan, N.

    2014-01-01

    The need for flexible, low-overhead virtualization is evident on many fronts ranging from high-density cloud servers to mobile devices. During the past decade OS-level virtualization has emerged as a new, efficient approach for virtualization, with implementations in multiple different Unix-based systems. Despite its popularity, there has been no systematic study of OS-level virtualization from the point of view of security. In this report, we conduct a comparative study of several OS-level v...

  10. Conceptual Design Scheme for Virtual Characters

    Science.gov (United States)

    Brunetti, Gino; Servidio, Rocco

    The aim of this paper is to describe some theoretical considerations about virtual character design. In recent years, many prototypes of cognitive and behavioral architectures have been developed to simulate human behavior in artificial agents. Analyzing recent studies, we assume that there exists a variety of computational models and methods in order to increase the cognitive abilities of the virtual characters. In our opinion, it is necessary to perform a synthesis of these approaches in order to improve the existing models and avoiding the application of new approaches. Considering these aspects, in this paper we describe a taxonomy that explores the principal cognitive and computational parameters involved in the design, development and evaluation of a virtual character.

  11. Seismic velocity estimation from time migration

    Energy Technology Data Exchange (ETDEWEB)

    Cameron, Maria Kourkina [Univ. of California, Berkeley, CA (United States)

    2007-01-01

    reliable as the earth becomes horizontally nonconstant. Even mild lateral velocity variations can significantly distort subsurface structures on the time migrated images. Conversely, depth migration provides the potential for more accurate reconstructions, since it can handle significant lateral variations. However, this approach requires good input data, known as a 'velocity model'. We address the problem of estimating seismic velocities inside the earth, i.e., the problem of constructing a velocity model, which is necessary for obtaining seismic images in regular Cartesian coordinates. The main goals are to develop algorithms to convert time-migration velocities to true seismic velocities, and to convert time-migrated images to depth images in regular Cartesian coordinates. Our main results are three-fold. First, we establish a theoretical relation between the true seismic velocities and the 'time migration velocities' using the paraxial ray tracing. Second, we formulate an appropriate inverse problem describing the relation between time migration velocities and depth velocities, and show that this problem is mathematically ill-posed, i.e., unstable to small perturbations. Third, we develop numerical algorithms to solve regularized versions of these equations which can be used to recover smoothed velocity variations. Our algorithms consist of efficient time-to-depth conversion algorithms, based on Dijkstra-like Fast Marching Methods, as well as level set and ray tracing algorithms for transforming Dix velocities into seismic velocities. Our algorithms are applied to both two-dimensional and three-dimensional problems, and we test them on a collection of both synthetic examples and field data.

  12. Sodium Velocity Maps on Mercury

    Science.gov (United States)

    Potter, A. E.; Killen, R. M.

    2011-01-01

    The objective of the current work was to measure two-dimensional maps of sodium velocities on the Mercury surface and examine the maps for evidence of sources or sinks of sodium on the surface. The McMath-Pierce Solar Telescope and the Stellar Spectrograph were used to measure Mercury spectra that were sampled at 7 milliAngstrom intervals. Observations were made each day during the period October 5-9, 2010. The dawn terminator was in view during that time. The velocity shift of the centroid of the Mercury emission line was measured relative to the solar sodium Fraunhofer line corrected for radial velocity of the Earth. The difference between the observed and calculated velocity shift was taken to be the velocity vector of the sodium relative to Earth. For each position of the spectrograph slit, a line of velocities across the planet was measured. Then, the spectrograph slit was stepped over the surface of Mercury at 1 arc second intervals. The position of Mercury was stabilized by an adaptive optics system. The collection of lines were assembled into an images of surface reflection, sodium emission intensities, and Earthward velocities over the surface of Mercury. The velocity map shows patches of higher velocity in the southern hemisphere, suggesting the existence of sodium sources there. The peak earthward velocity occurs in the equatorial region, and extends to the terminator. Since this was a dawn terminator, this might be an indication of dawn evaporation of sodium. Leblanc et al. (2008) have published a velocity map that is similar.

  13. From mapping to virtual geography

    DEFF Research Database (Denmark)

    Kjems, Erik; Kolar, Jan

    2005-01-01

    The history of mapping goes back hundreds of years. Many books and articles have been written on this topic as many different ways to present our world. This paper will not deal with cartography in a normal sense as indicated by the headline but will face and argue the necessity of dealing...... other plane. Many approaches have been made to build up our world in virtual spaces and create an illusion of spatiality, thus many different techniques have been developed to handle the modelling, the data acquisition, and the conversion between different software solutions and coordinate systems...

  14. Virtualization techniques for mobile systems

    CERN Document Server

    Jaramillo, David; Agarwal, Ankur

    2014-01-01

    This book presents effective ways to partition mobile devices such that the enterprise system access and its information are completely separated from the personal information. For those using mobile devices for personal and business purposes, the ability to keep the data secure and separate is critical. The applications for security in smart platforms range from personal email accounts to global enterprise systems.Several approaches for mobile virtualization are described, all creating secure and secluded environments for enterprise information. The authors present a reference architecture th

  15. The Virtual Dressing Room

    DEFF Research Database (Denmark)

    Holte, Michael Boelstoft; Gao, Yi; Petersson, Eva

    2015-01-01

    This paper presents the design and evaluation of a usability and user experience test of a virtual dressing room. First, we motivate and introduce our recent developed prototype of a virtual dressing room. Next, we present the research and test design grounded in related usability and user...... experience studies. We give a description of the experimental setup and the execution of the designed usability and user experience test. To this end, we report interesting results and discuss the results with respect to user-centered design and development of a virtual dressing room....

  16. Virtual neutron scattering experiments

    DEFF Research Database (Denmark)

    Overgaard, Julie Hougaard; Bruun, Jesper; May, Michael

    2016-01-01

    We describe how virtual experiments can be utilized in a learning design that prepares students for hands-on experiments at large-scale facilities. We illustrate the design by showing how virtual experiments are used at the Niels Bohr Institute in a master level course on neutron scattering....... In the last week of the course, students travel to a large-scale neutron scattering facility to perform real neutron scattering experiments. Through student interviews and survey answers, we argue, that the virtual training prepares the students to engage more fruitfully with experiments by letting them focus...

  17. Gain and phase of perceived virtual rotation evoked by electrical vestibular stimuli.

    Science.gov (United States)

    Peters, Ryan M; Rasman, Brandon G; Inglis, J Timothy; Blouin, Jean-Sébastien

    2015-07-01

    Galvanic vestibular stimulation (GVS) evokes a perception of rotation; however, very few quantitative data exist on the matter. We performed psychophysical experiments on virtual rotations experienced when binaural bipolar electrical stimulation is applied over the mastoids. We also performed analogous real whole body yaw rotation experiments, allowing us to compare the frequency response of vestibular perception with (real) and without (virtual) natural mechanical stimulation of the semicircular canals. To estimate the gain of vestibular perception, we measured direction discrimination thresholds for virtual and real rotations. Real direction discrimination thresholds decreased at higher frequencies, confirming multiple previous studies. Conversely, virtual direction discrimination thresholds increased at higher frequencies, implying low-pass filtering of the virtual perception process occurring potentially anywhere between afferent transduction and cortical responses. To estimate the phase of vestibular perception, participants manually tracked their perceived position during sinusoidal virtual and real kinetic stimulation. For real rotations, perceived velocity was approximately in phase with actual velocity across all frequencies. Perceived virtual velocity was in phase with the GVS waveform at low frequencies (0.05 and 0.1 Hz). As frequency was increased to 1 Hz, the phase of perceived velocity advanced relative to the GVS waveform. Therefore, at low frequencies GVS is interpreted as an angular velocity signal and at higher frequencies GVS becomes interpreted increasingly as an angular position signal. These estimated gain and phase spectra for vestibular perception are a first step toward generating well-controlled virtual vestibular percepts, an endeavor that may reveal the usefulness of GVS in the areas of clinical assessment, neuroprosthetics, and virtual reality. Copyright © 2015 the American Physiological Society.

  18. Virtual Treatment of Basilar Aneurysms Using Shape Memory Polymer Foam

    Science.gov (United States)

    Ortega, J. M.; Hartman, J.; Rodriguez, J. N.; Maitland, D. J.

    2012-11-01

    Numerical simulations are performed on patient-specific basilar aneurysms that are treated with shape memory polymer (SMP) foam. In order to assess the post-treatment hemodynamics, two modeling approaches are employed. In the first, the foam geometry is obtained from a micro-CT scan and the pulsatile blood flow within the foam is simulated for both Newtonian and non-Newtonian viscosity models. In the second, the foam is represented as a porous media continuum, which has permeability properties that are determined by computing the pressure gradient through the foam geometry over a range of flow speeds comparable to those of in vivo conditions. Virtual angiography and additional post-processing demonstrate that the SMP foam significantly reduces the blood flow speed within the treated aneurysms, while eliminating the high-frequency velocity fluctuations that are present prior to treatment. A prediction of the initial locations of thrombus formation throughout the SMP foam is obtained by means of a low fidelity thrombosis model that is based upon the residence time and shear rate of blood. The two modeling approaches capture similar qualitative trends for the initial locations of thrombus within the SMP foam.

  19. Kaleidoscopic motion and velocity illusions

    NARCIS (Netherlands)

    Helm, P.A. van der

    2007-01-01

    A novel class of vivid motion and velocity illusions for contrast-defined shapes is presented and discussed. The illusions concern a starlike wheel that, physically, rotates with constant velocity between stationary starlike inner and outer shapes but that, perceptually, shows pulsations, jolts

  20. Virtual neutron scattering experiments

    DEFF Research Database (Denmark)

    Overgaard, Julie Hougaard; Bruun, Jesper; May, Michael

    2017-01-01

    . In the last week of the course, students travel to a large-scale neutron scattering facility to perform real neutron scattering experiments. Through student interviews and survey answers, we argue, that the virtual training prepares the students to engage more fruitfully with experiments by letting them focus......We describe how virtual experiments can be utilized in a learning design that prepares students for hands-on experiments at large-scale facilities. We illustrate the design by showing how virtual experiments are used at the Niels Bohr Institute in a master level course on neutron scattering...... on physics and data rather than the overwhelming instrumentation. We argue that this is because they can transfer their virtual experimental experience to the real-life situation. However, we also find that learning is still situated in the sense that only knowledge of particular experiments is transferred...

  1. Virtual Factory Testbed

    Data.gov (United States)

    Federal Laboratory Consortium — The Virtual Factory Testbed (VFT) is comprised of three physical facilities linked by a standalone network (VFNet). The three facilities are the Smart and Wireless...

  2. Virtual neutron scattering experiments

    DEFF Research Database (Denmark)

    Overgaard, Julie Hougaard; Bruun, Jesper; May, Michael

    2016-01-01

    We describe how virtual experiments can be utilized in a learning design that prepares students for hands-on experiments at large-scale facilities. We illustrate the design by showing how virtual experiments are used at the Niels Bohr Institute in a master level course on neutron scattering....... In the last week of the course, students travel to a large-scale neutron scattering facility to perform real neutron scattering experiments. Through student interviews and survey answers, we argue, that the virtual training prepares the students to engage more fruitfully with experiments by letting them focus...... on physics and data rather than the overwhelming instrumentation. We argue that this is because they can transfer their virtual experimental experience to the real-life situation. However, we also find that learning is still situated in the sense that only knowledge of particular experiments is transferred...

  3. Virtual Organizations: An Overview

    Science.gov (United States)

    Nami, Mohammad Reza

    The need to remain competitive in the open market forces companies to concentrate on their core competencies while searching for alliances when additional skills or resources are needed to fulfill business opportunities. The changing business situation of companies and customer needs have motivated researchers to introduce Virtual Organization (VO) idea. A Virtual Organization is always a form of partnership and managing partners and handling partnerships are crucial. Virtual organizations are defined as a temporary collection of enterprises that cooperate and share resources, knowledge, and competencies to better respond to business opportunities. This paper presents base concepts of virtual organizations including properties, management concepts, operational concepts, and main issues in collaboration such as security and authentication.

  4. Cuenca, realidad virtual

    National Research Council Canada - National Science Library

    Concepción Rodríguez Ruza; Adela Mª Muñoz Marquina; Aurelio Lorente González; Virginia Cañas Córdoba

    2012-01-01

    This project, Cuenca, realidad virtual, was created so that the key periods of the historical evolution of Cuenca could be explained, where the Islamic Cuenca, Christian Cuenca and Cuenca in the 18th...

  5. Virtually Nursing: Emerging Technologies in Nursing Education.

    Science.gov (United States)

    Foronda, Cynthia L; Alfes, Celeste M; Dev, Parvati; Kleinheksel, A J; Nelson, Douglas A; OʼDonnell, John M; Samosky, Joseph T

    Augmented reality and virtual simulation technologies in nursing education are burgeoning. Preliminary evidence suggests that these innovative pedagogical approaches are effective. The aim of this article is to present 6 newly emerged products and systems that may improve nursing education. Technologies may present opportunities to improve teaching efforts, better engage students, and transform nursing education.

  6. Diffraction imaging and velocity analysis using oriented velocity continuation

    KAUST Repository

    Decker, Luke

    2014-08-05

    We perform seismic diffraction imaging and velocity analysis by separating diffractions from specular reflections and decomposing them into slope components. We image slope components using extrapolation in migration velocity in time-space-slope coordinates. The extrapolation is described by a convection-type partial differential equation and implemented efficiently in the Fourier domain. Synthetic and field data experiments show that the proposed algorithm is able to detect accurate time-migration velocities by automatically measuring the flatness of events in dip-angle gathers.

  7. Virtual realities and education

    OpenAIRE

    Curcio Igor D.D.; Dipace Anna; Norlund Anita

    2016-01-01

    The purpose of this article is to highlight the state of the art of virtual reality, augmented reality, mixed reality technologies and their applications in formal education. We also present a selected list of case studies that prove the utility of these technologies in the context of formal education. Furthermore, as byproduct, the mentioned case studies show also that, although the industry is able to develop very advanced virtual environment technologies, their pedagogical implications are...

  8. Transforming Virtual Teams

    DEFF Research Database (Denmark)

    Bjørn, Pernille

    2005-01-01

    Investigating virtual team collaboration in industry using grounded theory this paper presents the in-dept analysis of empirical work conducted in a global organization of 100.000 employees where a global virtual team with participants from Sweden, United Kingdom, Canada, and North America were...... multiple communities, and bringing visibility to articulation work, and that groupware technology should facilitate communication and negotiation instead of implementing the workflows just enhancing existing abilities, practices, and skills....

  9. Virtualization Technologies for the Business

    OpenAIRE

    Sabina POPESCU

    2011-01-01

    There is a new trend of change in today's IT industry. It's called virtualization. In datacenter virtualization can occur on several levels, but the type of virtualization has created this trend change is the operating system offered or server virtualization. OS virtualization technologies come in two forms. First, there is a software component that is used to simulate a natural machine that has total control of an operating system operating on the host equipment. The second is a hypervisor, ...

  10. Distributed Virtual Reality: System Concepts for Cooperative Training and Commanding in Virtual Worlds

    Directory of Open Access Journals (Sweden)

    Eckhard Freund

    2003-02-01

    Full Text Available The general aim of the development of virtual reality technology for automation applications at the IRF is to provide the framework for Projective Virtual Reality which allows users to "project" their actions in the virtual world into the real world primarily by means of robots but also by other means of automation. The framework is based on a new task-oriented approach which builds on the "task deduction" capabilities of a newly developed virtual reality system and a task planning component. The advantage of this new approach is that robots which work at great distances from the control station can be controlled as easily and intuitively as robots that work right next to the control station. Robot control technology now provides the user in the virtual world with a "prolonged arm" into the physical environment, thus paving the way for a new quality of userfriendly man machine interfaces for automation applications. Lately, this work has been enhanced by a new structure that allows to distribute the virtual reality application over multiple computers. With this new step, it is now possible for multiple users to work together in the same virtual room, although they may physically be thousands of miles apart. They only need an Internet or ISDN connection to share this new experience. Last but not least, the distribution technology has been further developed to not just allow users to cooperate but to be able to run the virtual world on many synchronized PCs so that a panorama projection or even a cave can be run with 10 synchronized PCs instead of high-end workstations, thus cutting down the costs for such a visualization environment drastically and allowing for a new range of applications.

  11. New GNSS velocity field and preliminary velocity model for Ecuador

    Science.gov (United States)

    Luna-Ludeña, Marco P.; Staller, Alejandra; Gaspar-Escribano, Jorge M.; Belén Benito, M.

    2016-04-01

    In this work, we present a new preliminary velocity model of Ecuador based on the GNSS data of the REGME network (continuous monitoring GNSS network). To date, there is no velocity model available for the country. The only existing model in the zone is the regional model VEMOS2009 for South America and Caribbean (Drewes and Heidbach, 2012). This model was developed from the SIRGAS station positions, the velocities of the SIRGAS-CON stations, and several geodynamics projects performed in the region. Just two continuous GNSS (cGNSS) stations of Ecuador were taking into account in the VEMOS2009 model. The first continuous station of the REGME network was established in 2008. At present, it is composed by 32 continuous GNSS stations, covering the country. All the stations provided data during at least two years. We processed the data of the 32 GNSS stations of REGME for the 2008-2014 period, as well as 20 IGS stations in order to link to the global reference frame IGb08 (ITRF2008). GPS data were processed using Bernese 5.0 software (Dach et al., 2007). We obtained and analyzed the GNSS coordinate time series of the 32 REGME stations and we calculated the GPS-derived horizontal velocity field of the country. Velocities in ITRF2008 were transformed into a South American fixed reference frame, using the Euler pole calculated from 8 cGNSS stations throughout this plate. Our velocity field is consistent with the tectonics of the country and contributes to a better understanding of it. From the horizontal velocity field, we determined a preliminary model using the kriging geostatistical technique. To check the results we use the cross-validation method. The differences between the observed and estimated values range from ± 5 mm. This is a new velocity model obtained from GNSS data for Ecuador.

  12. Availability Analysis and Improvement of Software Rejuvenation Using Virtualization

    National Research Council Canada - National Science Library

    PARK, Jong Sou; Thandar, THEIN; Sung-Do, CHI

    2007-01-01

    .... To improve the availability of application servers, we have conducted a study of virtualization technology and software rejuvenation that follows a proactive fault-tolerant approach to counter act...

  13. Evaluation of Security Mechanisms for Virtual Organizations

    Science.gov (United States)

    Wu, Jake; Periorellis, Panos

    GOLD project is concerned with dynamic formation and management of virtual organizations in order to exploit market opportunities. The project aims to deliver the enabling technology to support the full lifecycle of such VOs. A set of middleware technologies have been designed and implemented to address issues such as trust, security, contract management, monitoring and information management for virtual collaboration between companies. In this paper we will showcase some of the more general requirements for authentication and authorization in GOLD VOs. In conjunction with these requirements we evaluate some of the more popular tools that are currently available in dealing with these issues, together with our own approach in addressing these problems.

  14. The Virtual Water Transactions Promote Environmental Justice?

    Directory of Open Access Journals (Sweden)

    Thaís Dalla Corte

    2016-12-01

    Full Text Available As natural water, virtual water is essential for the dynamics of life. It, that correspond to the total volume of fresh water used in the production process in one place and that was incorporated into the final goods, is a calculation that can contribute to human access to water be assured in sufficient quantities for a dignified life. Therefore, the objective of this research is, through the hypothetical-deductive method of approach, evaluate virtual water transfers from the perspective of environmental justice in a globalized world in the Anthropocene.

  15. Adapting virtual camera behaviour through player modelling

    DEFF Research Database (Denmark)

    Burelli, Paolo; Yannakakis, Georgios N.

    2015-01-01

    a novel approach to virtual camera control, which builds upon camera control and player modelling to provide the user with an adaptive point-of-view. To achieve this goal, we propose a methodology to model the player’s preferences on virtual camera movements and we employ the resulting models to tailor...... the viewpoint movements to the player type and her game-play style. Ultimately, the methodology is applied to a 3D platform game and is evaluated through a controlled experiment; the results suggest that the resulting adaptive cinematographic experience is favoured by some player types and it can generate...

  16. Ion mobility spectrometer with virtual aperture grid

    Science.gov (United States)

    Pfeifer, Kent B.; Rumpf, Arthur N.

    2010-11-23

    An ion mobility spectrometer does not require a physical aperture grid to prevent premature ion detector response. The last electrodes adjacent to the ion collector (typically the last four or five) have an electrode pitch that is less than the width of the ion swarm and each of the adjacent electrodes is connected to a source of free charge, thereby providing a virtual aperture grid at the end of the drift region that shields the ion collector from the mirror current of the approaching ion swarm. The virtual aperture grid is less complex in assembly and function and is less sensitive to vibrations than the physical aperture grid.

  17. Instant Hyper-v Server Virtualization starter

    CERN Document Server

    Eguibar, Vicente Rodriguez

    2013-01-01

    Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks.The approach would be in a tutorial manner that will guide the users in an orderly manner toward virtualization.This book is conceived for system administrator and advanced PC enthusiasts who want to venture into the virtualization world. Although this book goes from scratch up, knowledge on server Operative Systems, LAN and networking has to be in place. Having a good background on server administration is desirable, including networking service

  18. Vehicle Yaw Rate Estimation Using a Virtual Sensor

    Directory of Open Access Journals (Sweden)

    Mümin Tolga Emirler

    2013-01-01

    Full Text Available Road vehicle yaw stability control systems like electronic stability program (ESP are important active safety systems used for maintaining lateral stability of the vehicle. Vehicle yaw rate is the key parameter that needs to be known by a yaw stability control system. In this paper, yaw rate is estimated using a virtual sensor which contains kinematic relations and a velocity-scheduled Kalman filter. Kinematic estimation is carried out using wheel speeds, dynamic tire radius, and front wheel steering angle. In addition, a velocity-scheduled Kalman filter utilizing the linearized single-track model of the road vehicle is used in the dynamic estimation part of the virtual sensor. The designed virtual sensor is successfully tested offline using a validated, high degrees of freedom, and high fidelity vehicle model and using hardware-in-the-loop simulations. Moreover, actual road testing is carried out and the estimated yaw rate from the virtual sensor is compared with the actual yaw rate obtained from the commercial yaw rate sensor to demonstrate the effectiveness of the virtual yaw rate sensor in practical use.

  19. Solvable Optimal Velocity Models and Asymptotic Trajectory

    CERN Document Server

    Nakanishi, K; Igarashi, Y; Bando, M

    1996-01-01

    In the Optimal Velocity Model proposed as a new version of Car Following Model, it has been found that a congested flow is generated spontaneously from a homogeneous flow for a certain range of the traffic density. A well-established congested flow obtained in a numerical simulation shows a remarkable repetitive property such that the velocity of a vehicle evolves exactly in the same way as that of its preceding one except a time delay $T$. This leads to a global pattern formation in time development of vehicles' motion, and gives rise to a closed trajectory on $\\Delta x$-$v$ (headway-velocity) plane connecting congested and free flow points. To obtain the closed trajectory analytically, we propose a new approach to the pattern formation, which makes it possible to reduce the coupled car following equations to a single difference-differential equation (Rondo equation). To demonstrate our approach, we employ a class of linear models which are exactly solvable. We also introduce the concept of ``asymptotic traj...

  20. RADIAL VELOCITY ECLIPSE MAPPING OF EXOPLANETS

    Energy Technology Data Exchange (ETDEWEB)

    Nikolov, Nikolay; Sainsbury-Martinez, Felix, E-mail: nikolay@astro.ex.ac.uk [Astrophysics Group, School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom)

    2015-07-20

    Planetary rotation rates and obliquities provide information regarding the history of planet formation, but have not yet been measured for evolved extrasolar planets. Here we investigate the theoretical and observational perspective of the Rossiter–McLaughlin effect during secondary eclipse (RMse) ingress and egress for transiting exoplanets. Near secondary eclipse, when the planet passes behind the parent star, the star sequentially obscures light from the approaching and receding parts of the rotating planetary surface. The temporal block of light emerging from the approaching (blueshifted) or receding (redshifted) parts of the planet causes a temporal distortion in the planet’s spectral line profiles resulting in an anomaly in the planet’s radial velocity curve. We demonstrate that the shape and the ratio of the ingress-to-egress radial velocity amplitudes depends on the planetary rotational rate, axial tilt, and impact factor (i.e., sky-projected planet spin–orbital alignment). In addition, line asymmetries originating from different layers in the atmosphere of the planet could provide information regarding zonal atmospheric winds and constraints on the hot spot shape for giant irradiated exoplanets. The effect is expected to be most-pronounced at near-infrared wavelengths, where the planet-to-star contrasts are large. We create synthetic near-infrared, high-dispersion spectroscopic data and demonstrate how the sky-projected spin axis orientation and equatorial velocity of the planet can be estimated. We conclude that the RMse effect could be a powerful method to measure exoplanet spins.