Four-quadrant flyback converter for direct audio power amplification

Energy Technology Data Exchange (ETDEWEB)

Ljusev, P.; Andersen, Michael A.E.

2005-07-01

This paper presents a bidirectional, four-quadrant yback converter for use in direct audio power amplication. When compared to the standard Class-D switching-mode audio power amplier with separate power supply, the proposed four-quadrant flyback converter provides simple and compact solution with high efciency, higher level of integration, lower component count, less board space and eventually lower cost. Both peak and average current-mode control for use with 4Q flyback power converters are described and compared. Integrated magnetics is presented which simplies the construction of the auxiliary power supplies for control biasing and isolated gate drives. The feasibility of the approach is proven on audio power amplier prototype for subwoofer applications. (au)

Research on correction algorithm of laser positioning system based on four quadrant detector

Science.gov (United States)

Gao, Qingsong; Meng, Xiangyong; Qian, Weixian; Cai, Guixia

2018-02-01

This paper first introduces the basic principle of the four quadrant detector, and a set of laser positioning experiment system is built based on the four quadrant detector. Four quadrant laser positioning system in the actual application, not only exist interference of background light and detector dark current noise, and the influence of random noise, system stability, spot equivalent error can't be ignored, so it is very important to system calibration and correction. This paper analyzes the various factors of system positioning error, and then propose an algorithm for correcting the system error, the results of simulation and experiment show that the modified algorithm can improve the effect of system error on positioning and improve the positioning accuracy.

Fat-containing lesions revealed by CT in children with right lower quadrant pain

International Nuclear Information System (INIS)

Maxfield, Charles M.; Bayindir, Petek

2009-01-01

Suspected appendicitis is the most common indication for emergent abdominal surgery in children. The clinical diagnosis of appendicitis can be challenging, and CT is playing an increasing role in the evaluation of right lower quadrant pain. Occasionally, alternative diagnoses to appendicitis can be suggested on CT. The appreciation of a fat-containing lesion in the right lower quadrant will often allow a specific diagnosis. Importantly, many of these lesions are self-limited and treated nonoperatively. The purpose of this pictorial essay is to illustrate the spectrum of fat-containing lesions that can present as alternative diagnoses to appendicitis on CT scans performed for the evaluation of right lower quadrant pain in children. (orig.)

Fat-containing lesions revealed by CT in children with right lower quadrant pain

Energy Technology Data Exchange (ETDEWEB)

Maxfield, Charles M. [Duke University Medical Center, Department of Radiology, Durham, NC (United States); Bayindir, Petek [Ege University Medical Faculty, Department of Radiology, Bornova, Izmir (Turkey)

2009-04-15

Suspected appendicitis is the most common indication for emergent abdominal surgery in children. The clinical diagnosis of appendicitis can be challenging, and CT is playing an increasing role in the evaluation of right lower quadrant pain. Occasionally, alternative diagnoses to appendicitis can be suggested on CT. The appreciation of a fat-containing lesion in the right lower quadrant will often allow a specific diagnosis. Importantly, many of these lesions are self-limited and treated nonoperatively. The purpose of this pictorial essay is to illustrate the spectrum of fat-containing lesions that can present as alternative diagnoses to appendicitis on CT scans performed for the evaluation of right lower quadrant pain in children. (orig.)

Detecting positive quadrant dependence and positive function dependence

NARCIS (Netherlands)

Janic-Wróblewska, A.; Kallenberg, W.C.M.; Ledwina, T.

2004-01-01

There is a lot of interest in positive dependence going beyond linear correlation. In this paper three new rank tests for testing independence against positive dependence are introduced. The first one is directed on positive quadrant dependence, the second and third one concentrate on positive

Detecting positive quadrant dependence and positive function dependence

NARCIS (Netherlands)

Janic-Wróblewska, A.; Kallenberg, W.C.M.; Ledwina, T.

2003-01-01

There is a lot of interest in positive dependence going beyond linear correlation. In this paper three new rank tests for testing independence against positive dependence are introduced. The first one is directed on positive quadrant dependence, the second and third one concentrate on positive

Four-quadrant propeller modeling: A low-order harmonic approximation

Digital Repository Service at National Institute of Oceanography (India)

Haeusler, A.J; Saccon, A.; Hauser, J; Pascoal, A.M.; Aguiar, A.P.

. We explore the connection between the propeller thrust, torque, and efficiency curves and the lift and drag curves of the propeller blades. The model originates from a well-known four-quadrant model, based on a sinusoidal approximation...

Turbulent Reynolds stress and quadrant event activity in wind flow over a coastal foredune

Science.gov (United States)

Chapman, Connie A.; Walker, Ian J.; Hesp, Patrick A.; Bauer, Bernard O.; Davidson-Arnott, Robin G. D.

2012-05-01

Recent research on quasi-instantaneous turbulent kinematic Reynolds stresses (RS, - u'w') and decomposed quadrant event activity (e.g., ejections and sweeps) over dunes in fluvial settings and in wind tunnels has shown that turbulent stresses at the toe of a dune often exceed time-averaged, streamwise shear stress (ρ u * 2) estimates. It is believed that semi-coherent turbulent structures are conveyed toward the bed along concave streamlines in this region and that impact of these structures cause fluctuations in local surface stresses that assist in grain entrainment. This has been hypothesized to explain how sand is supplied to the windward slope through a region of flow stagnation. Toward the crest, surface stress increases and becomes dominated by streamwise accelerations resulting from streamline compression and convexity that suppress vertical motions. High-frequency (32 Hz) measurements of turbulent wind flow from 3-D ultrasonic anemometers are analyzed for oblique onshore flow over a vegetated coastal foredune in Prince Edward Island, Canada. Reynolds stress and quadrant activity distributions varied with height (0.60 m and 1.66 m) and location over the dune. In general, quadrant 2 ejection (u' 0) and quadrant 4 sweep activity (u' > 0, w' 0, w' > 0) and quadrant 3 inward interaction (u' dune and may help to explain sand transport potential and dune maintenance. For example, areas with a high frequency of ejection and sweep activity may have higher rates of sediment entrainment and transport, whereas areas with lower ejection and sweep activity and an increase in outward and inward interactions, which contribute negatively to Reynolds stress generation, may experience a greater potential for deposition. Further research on associations between quadrant event activity and coincident sand transport is required to confirm this hypothesis and the resultant significance of the flow exuberance effect in aeolian dune morphodynamics.

Comparison of Optic Nerve Head Blood Flow Autoregulation among Quadrants Induced by Decreased Ocular Perfusion Pressure during Vitrectomy

Directory of Open Access Journals (Sweden)

Ryuya Hashimoto

2017-01-01

Full Text Available Purpose. The present study aimed to examine changes in optic nerve head (ONH blood flow autoregulation in 4 quadrants (superior, nasal, inferior, and temporal with decreased ocular perfusion pressure (OPP during vitrectomy in order to determine whether there is a significant difference of autoregulatory capacity in response to OPP decrease at each ONH quadrant. Methods. This study included 24 eyes with an epiretinal membrane or macular hole that underwent vitrectomy at Toho University Sakura Medical Center. Following vitrectomy, the tissue mean blur rate (MBR, which reflects ONH blood flow, was measured. Mean tissue MBRs in the four quadrants were generated automatically in the software analysis report. Measurements were conducted before and 5 and 10 min after intraocular pressure (IOP elevation of approximately 15 mmHg in the subjects without systemic disorders. Results. The baseline tissue MBR of the temporal quadrant was significantly lower than that of the other 3 quadrants (all P<0.05. However, the time courses of tissue MBR in response to OPP decrease were not significantly different among the four quadrants during vitrectomy (P=0.23. Conclusions. There is no significant difference in the autoregulatory capacity of the four ONH quadrants in patients without systemic disorders during vitrectomy.

Cancellation of OpAmp virtual ground imperfections by a negative conductance applied to improve RF receiver linearity

NARCIS (Netherlands)

Mahrof, D.H.; Klumperink, Eric A.M.; Ru, Z.; Oude Alink, M.S.; Nauta, Bram

2014-01-01

High linearity CMOS radio receivers often exploit linear V-I conversion at RF, followed by passive down-mixing and an OpAmp-based Transimpedance Amplifier at baseband. Due to nonlinearity and finite gain in the OpAmp, virtual ground is imperfect, inducing distortion currents. This paper proposes a

The assessment of virtual reality for human anatomy instruction

Science.gov (United States)

Benn, Karen P.

1994-01-01

This research project seeks to meet the objective of science training by developing, assessing, and validating virtual reality as a human anatomy training medium. In ideal situations, anatomic models, computer-based instruction, and cadaver dissection are utilized to augment the traditional methods of instruction. At many institutions, lack of financial resources limits anatomy instruction to textbooks and lectures. However, human anatomy is three dimensional, unlike the one dimensional depiction found in textbooks and the two dimensional depiction found on the computer. Virtual reality is a breakthrough technology that allows one to step through the computer screen into a three dimensional world. This technology offers many opportunities to enhance science education. Therefore, a virtual testing environment of the abdominopelvic region of a human cadaver was created to study the placement of body parts within the nine anatomical divisions of the abdominopelvic region and the four abdominal quadrants.

In vivo precision of conventional and digital methods for obtaining quadrant dental impressions

OpenAIRE

Ender, Andreas; Zimmermann, Moritz; Attin, Thomas; Mehl, Albert

2016-01-01

OBJECTIVES Quadrant impressions are commonly used as alternative to full-arch impressions. Digital impression systems provide the ability to take these impressions very quickly; however, few studies have investigated the accuracy of the technique in vivo. The aim of this study is to assess the precision of digital quadrant impressions in vivo in comparison to conventional impression techniques. MATERIALS AND METHODS Impressions were obtained via two conventional (metal full-arch tray, CI, ...

Oncoplastic Surgery for Upper/Upper Inner Quadrant Breast Cancer.

Science.gov (United States)

Lin, Joseph; Chen, Dar-Ren; Wang, Yu-Fen; Lai, Hung-Wen

2016-01-01

Tumors located in the upper/upper inner quadrant of the breast warrant more attention. A small lesion relative to the size of breast in this location may be resolved by performing a level I oncoplastic technique. However, a wide excision may significantly reduce the overall quality of the breast shape by distorting the visible breast line. From June 2012 to April 2015, 36 patients with breast cancer located in the upper/upper inner quadrant underwent breast-conservation surgery with matrix rotation mammoplasty. According to the size and location of the tumor relative to the nipple-areola complex, 11 patients underwent matrix rotation with periareolar de-epithelialization (donut group) and the other 25 underwent matrix rotation only (non-donut group). The cosmetic results were self-assessed by questionnaires. The average weights of the excised breast lumps in the donut and non-donut groups were 104.1 and 84.5 g, respectively. During the 3-year follow-up period, local recurrence was observed in one case and was managed with nipple-sparing mastectomy followed by breast reconstruction with prosthetic implants. In total, 31 patients (88.6%) ranked their postoperative result as either acceptable or satisfactory. The treated breasts were also self-evaluated by 27 patients (77.1%) to be nearly identical to or just slightly different from the untreated side. Matrix rotation is an easy breast-preserving technique for treating breast cancer located in the upper/upper inner quadrant of the breast that requires a relatively wide excision. With this technique, a larger breast tumor could be removed without compromising the breast appearance.

Neural Network Predictions of the 4-Quadrant Wageningen Propeller Series

National Research Council Canada - National Science Library

Roddy, Robert F; Hess, David E; Faller, Will

2006-01-01

.... This report describes the development of feedforward neural network (FFNN) predictions of four-quadrant thrust and torque behavior for the Wageningen B-Screw Series of propellers and for two Wageningen ducted propeller series...

Oncoplastic Surgery for Upper/Upper Inner Quadrant Breast Cancer.

Directory of Open Access Journals (Sweden)

Joseph Lin

Full Text Available Tumors located in the upper/upper inner quadrant of the breast warrant more attention. A small lesion relative to the size of breast in this location may be resolved by performing a level I oncoplastic technique. However, a wide excision may significantly reduce the overall quality of the breast shape by distorting the visible breast line. From June 2012 to April 2015, 36 patients with breast cancer located in the upper/upper inner quadrant underwent breast-conservation surgery with matrix rotation mammoplasty. According to the size and location of the tumor relative to the nipple-areola complex, 11 patients underwent matrix rotation with periareolar de-epithelialization (donut group and the other 25 underwent matrix rotation only (non-donut group. The cosmetic results were self-assessed by questionnaires. The average weights of the excised breast lumps in the donut and non-donut groups were 104.1 and 84.5 g, respectively. During the 3-year follow-up period, local recurrence was observed in one case and was managed with nipple-sparing mastectomy followed by breast reconstruction with prosthetic implants. In total, 31 patients (88.6% ranked their postoperative result as either acceptable or satisfactory. The treated breasts were also self-evaluated by 27 patients (77.1% to be nearly identical to or just slightly different from the untreated side. Matrix rotation is an easy breast-preserving technique for treating breast cancer located in the upper/upper inner quadrant of the breast that requires a relatively wide excision. With this technique, a larger breast tumor could be removed without compromising the breast appearance.

In vivo precision of conventional and digital methods for obtaining quadrant dental impressions.

Science.gov (United States)

Ender, Andreas; Zimmermann, Moritz; Attin, Thomas; Mehl, Albert

2016-09-01

Quadrant impressions are commonly used as alternative to full-arch impressions. Digital impression systems provide the ability to take these impressions very quickly; however, few studies have investigated the accuracy of the technique in vivo. The aim of this study is to assess the precision of digital quadrant impressions in vivo in comparison to conventional impression techniques. Impressions were obtained via two conventional (metal full-arch tray, CI, and triple tray, T-Tray) and seven digital impression systems (Lava True Definition Scanner, T-Def; Lava Chairside Oral Scanner, COS; Cadent iTero, ITE; 3Shape Trios, TRI; 3Shape Trios Color, TRC; CEREC Bluecam, Software 4.0, BC4.0; CEREC Bluecam, Software 4.2, BC4.2; and CEREC Omnicam, OC). Impressions were taken three times for each of five subjects (n = 15). The impressions were then superimposed within the test groups. Differences from model surfaces were measured using a normal surface distance method. Precision was calculated using the Perc90_10 value. The values for all test groups were statistically compared. The precision ranged from 18.8 (CI) to 58.5 μm (T-Tray), with the highest precision in the CI, T-Def, BC4.0, TRC, and TRI groups. The deviation pattern varied distinctly depending on the impression method. Impression systems with single-shot capture exhibited greater deviations at the tooth surface whereas high-frame rate impression systems differed more in gingival areas. Triple tray impressions displayed higher local deviation at the occlusal contact areas of upper and lower jaw. Digital quadrant impression methods achieve a level of precision, comparable to conventional impression techniques. However, there are significant differences in terms of absolute values and deviation pattern. With all tested digital impression systems, time efficient capturing of quadrant impressions is possible. The clinical precision of digital quadrant impression models is sufficient to cover a broad variety of

A Four-Quadrant PVDF Transducer for Surface Acoustic Wave Detection

Directory of Open Access Journals (Sweden)

Zhi Chen

2012-08-01

Full Text Available In this paper, a polyvinylidene fluoride (PVDF piezoelectric transducer was developed to detect laser-induced surface acoustic waves in a SiO₂-thin film–Si-substrate structure. In order to solve the problems related to, firstly, the position of the probe, and secondly, the fact that signals at different points cannot be detected simultaneously during the detection process, a four-quadrant surface acoustic wave PVDF transducer was designed and constructed for the purpose of detecting surface acoustic waves excited by a pulse laser line source. The experimental results of the four-quadrant piezoelectric detection in comparison with the commercial nanoindentation technology were consistent, the relative error is 0.56%, and the system eliminates the piezoelectric surface wave detection direction deviation errors, improves the accuracy of the testing system by 1.30%, achieving the acquisition at the same time at different testing positions of the sample.

Ultra-low-power, class-AB, CMOS four-quadrant current multiplier

NARCIS (Netherlands)

Sawigun, C.; Serdijn, W.A.

2009-01-01

A class-AB four-quadrant current multiplier constituted by a class-AB current amplifier and a current splitter which can handle input signals in excess of ten times the bias current is presented. The proposed circuit operation is based on the exponential characteristic of BJTs or subthreshold

Treatment planning of implants in posterior quadrants.

Science.gov (United States)

Jivraj, S; Chee, W

2006-07-08

Differences in anatomy and biomechanics make treatment of posterior quadrants with dental implants substantially different to that of anterior areas. Without implants, when posterior teeth were lost, treatment options included a long span fixed partial denture or a removable prosthesis, especially when no terminal abutment was available. Today, with the use of implants, options are available that allow preservation of unrestored teeth.(1) When teeth are missing, implant supported restorations can be considered the treatment of choice from the perspective of occlusal support, preservation of adjacent teeth and avoidance of a removable partial denture.

Physical Activity Characteristics across GOLD Quadrants Depend on the Questionnaire Used.

Directory of Open Access Journals (Sweden)

Heleen Demeyer

Full Text Available The GOLD multidimensional classification of COPD severity combines the exacerbation risk with the symptom experience, for which 3 different questionnaires are permitted. This study investigated differences in physical activity (PA in the different GOLD quadrants and patient's distribution in relation to the questionnaire used.136 COPD patients (58±21% FEV1 predicted, 34F/102M completed COPD assessment test (CAT, clinical COPD questionnaire (CCQ and modified Medical Research Council (mMRC questionnaire. Exacerbation history, spirometry and 6MWD were collected. PA was objectively measured for 2 periods of 1 week, 6 months apart, in 5 European centres; to minimise seasonal and clinical variation the average of these two periods was used for analysis.GOLD quadrants C+D had reduced PA compared with A+B (3824 [2976] vs. 5508 [4671] steps.d-1, p<0.0001. The choice of questionnaire yielded different patient distributions (agreement mMRC-CAT κ = 0.57; CCQ-mMRC κ = 0.71; CCQ-CAT κ = 0.72 with different clinical characteristics. PA was notably lower in patients with an mMRC score ≥2 (3430 [2537] vs. 5443 [3776] steps.d-1, p <0.001 in both the low and high risk quadrants.Using different questionnaires changes the patient distribution and results in different clinical characteristics. Therefore, standardization of the questionnaire used for classification is critical to allow comparison of different studies using this as an entry criterion.ClinicalTrials.gov NCT01388218.

Implementation of an AlGaN-based solar-blind UV four-quadrant detector

Energy Technology Data Exchange (ETDEWEB)

Schalkwyk, L. van, E-mail: Louwrens.VanSchalkwyk@up.ac.za; Meyer, W.E.; Nel, J.M.; Auret, F.D.; Ngoepe, P.N.M.

2014-04-15

An AlGaN-based front illuminated intrinsically solar-blind ultraviolet four-quadrant Schottky detector was fabricated and characterized. A layered ohmic structure was deposited followed by a multi-step annealing method. Ultraviolet transmissive iridium oxide was used as the Schottky barrier material and formed by a two-step annealing method. Au contacts were deposited on the Schottky contacts and annealed. The detector was mounted onto a commercial chip carrier and wires were epoxy bonded from the ohmic and Au contacts to the carrier strips. The detector had an average ideality factor of 1.97±0.08, a Schottky barrier height of (1.22±0.07) eV, a reverse leakage current density of (2.1±4) nA/cm{sup 2}, a series resistance of (120±30)Ω and a free carrier concentration of (1.6±0.3)×10{sup 18}cm{sup −3}. Spectral characterization on the photosensitive area of 7.3×10{sup −3}cm{sup 2} yielded a cut-off wavelength at (275±5)nm (4.59 eV to 4.23 eV) for each quadrant, corresponding to the absorption edge of a (46±3)% Al content AlGaN-based material. The detector had an average responsivity of (28±2) mA/W and a quantum efficiency of (14±1)% at 250 nm. The ultraviolet-to-visible and near-infrared rejection ratio was between 10{sup 3} and 10{sup 5} for most of the quadrants. Characterization showed uniformity across the quadrants, proving the detector feasible for implementation in future ultraviolet-sensitive electro-optic devices.

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...

Neural Network Predictions of the 4-Quadrant Wageningen Propeller Series (CD-ROM)

National Research Council Canada - National Science Library

Roddy, Robert F; Hess, David E; Faller, Will

2006-01-01

.... This report describes the development of feedforward neural network (FFNN) predictions of four-quadrant thrust and torque behavior for the Wageningen B-Screw Series of propellers and for two Wageningen ducted propeller series...

Proposal for the award of a contract for the supply of four-quadrant switched-mode power converters rated at ±60A, ±8V for the LHC

CERN Document Server

2003-01-01

This document concerns the award of a contract for the supply of 834 four-quadrant switched-mode power converters rated at ±60A, ±8V and 200 racks for the LHC. Following a market survey carried out among 154 firms in nineteen Member States, a call for tenders (IT-2944/AB/LHC) was sent on 2 May 2003 to 11 firms and three consortia in twelve Member States. By the closing date, CERN had received eight tenders from eight firms in six Member States. The Finance Committee is invited to agree to the negotiation of a contract with CEL (FR), the lowest bidder complying with the specification, for the supply of 834 four-quadrant switched-mode power converters and 200 racks for a total amount of 2 343 808 euros (3 580 629 Swiss francs), not subject to revision, with an option for additional four-quadrant switched-mode power converters and racks for a total amount of 215 301 euros (328 915 Swiss francs), subject to revision for inflation from 1 January 2006, bringing the overall total to 2 559 109 euros (3 909 544 Swis...

Comparison of gonioscopy and anterior segment ocular coherence tomography in detecting angle closure in different quadrants of the anterior chamber angle.

Science.gov (United States)

Sakata, Lisandro M; Lavanya, Raghavan; Friedman, David S; Aung, Han T; Gao, Hong; Kumar, Rajesh S; Foster, Paul J; Aung, Tin

2008-05-01

To compare the performance of gonioscopy and anterior segment (AS) optical coherence tomography (OCT) in detecting angle closure in the different quadrants of the anterior chamber angle (ACA). Cross-sectional observational study. Five hundred two consecutive subjects more than 50 years of age with no previous ophthalmic problems recruited from a community clinic in Singapore. All subjects underwent gonioscopy and AS OCT imaging in the dark. Using gonioscopy, the ACA was graded using the Scheie system by a single examiner masked to AS OCT findings. The ACA in a particular quadrant was classified as closed if the posterior trabecular meshwork could not be seen on gonioscopy. A closed ACA on AS OCT imaging was defined by the presence of any contact between the iris and angle wall anterior to the scleral spur. After excluding eyes with poor image quality, a total of 423 right eyes were included in the analysis. A closed angle in at least 1 quadrant was observed in 59% of the eyes by AS OCT and in 33% of the eyes by gonioscopy (Pgonioscopy were 48% versus 29% superiorly, 43% versus 22% inferiorly, 18% versus 14% nasally, and 12% versus 20% temporally, respectively. Of the 119 of 1692 quadrants that were closed on gonioscopy but open on AS OCT, a steep iris profile was present in 61 (51%) of 119 quadrants on AS OCT, and of the 276 of 1692 quadrants that were open on gonioscopy but closed on AS OCT, 196 (71%) of 276 quadrants showed short iridoangle contact on AS OCT. The highest rates of closed angles on gonioscopy and AS OCT images were observed in the superior quadrant. Anterior segment OCT tended to detect more closed ACAs than gonioscopy, particularly in the superior and inferior quadrants. Variations in the iris profile and level of iridoangle contact also may explain some of the differences seen between gonioscopy and AS OCT.

Physical Activity Characteristics across GOLD Quadrants Depend on the Questionnaire Used

Science.gov (United States)

Demeyer, Heleen; Gimeno-Santos, Elena; Rabinovich, Roberto A.; Hornikx, Miek; Louvaris, Zafeiris; de Boer, Willem I.; Karlsson, Niklas; de Jong, Corina; Van der Molen, Thys; Vogiatzis, Ioannis; Janssens, Wim; Garcia-Aymerich, Judith; Troosters, Thierry; Polkey, Michael I.

2016-01-01

Background The GOLD multidimensional classification of COPD severity combines the exacerbation risk with the symptom experience, for which 3 different questionnaires are permitted. This study investigated differences in physical activity (PA) in the different GOLD quadrants and patient’s distribution in relation to the questionnaire used. Methods 136 COPD patients (58±21% FEV1 predicted, 34F/102M) completed COPD assessment test (CAT), clinical COPD questionnaire (CCQ) and modified Medical Research Council (mMRC) questionnaire. Exacerbation history, spirometry and 6MWD were collected. PA was objectively measured for 2 periods of 1 week, 6 months apart, in 5 European centres; to minimise seasonal and clinical variation the average of these two periods was used for analysis. Results GOLD quadrants C+D had reduced PA compared with A+B (3824 [2976] vs. 5508 [4671] steps.d-1, p<0.0001). The choice of questionnaire yielded different patient distributions (agreement mMRC-CAT κ = 0.57; CCQ-mMRC κ = 0.71; CCQ-CAT κ = 0.72) with different clinical characteristics. PA was notably lower in patients with an mMRC score ≥2 (3430 [2537] vs. 5443 [3776] steps.d-1, p <0.001) in both the low and high risk quadrants. Conclusions Using different questionnaires changes the patient distribution and results in different clinical characteristics. Therefore, standardization of the questionnaire used for classification is critical to allow comparison of different studies using this as an entry criterion. Clinical Trial Registration ClinicalTrials.gov NCT01388218 PMID:26974332

Large Signal Model of a Four-quadrant AC to DC Converter for Accelerator Magnets

CERN Document Server

De la Calle, R; Rinaldi, L; Völker, F V

2001-01-01

This paper presents the large signal model of a four-quadrant AC to DC converter, which is expected to be used in the area of particle accelerators. The system’s first stage is composed of a three-phase boost PWM (Pulse Width Modulated) rectifier with DSP (Digital Signal Processing) based power factor correction (PFC) and output voltage regulation. The second stage is a full-bridge PWM inverter that allows fast four-quadrant operation. The structure is fully reversible, and an additional resistance (brake chopper) is not needed to dissipate the energy when the beam deflection magnet acts as generator.

Clinical presentation and manual therapy for lower quadrant musculoskeletal conditions.

Science.gov (United States)

Courtney, Carol A; Clark, Jeffrey D; Duncombe, Alison M; O'Hearn, Michael A

2011-11-01

Chronic lower quadrant injuries constitute a significant percentage of the musculoskeletal cases seen by clinicians. While impairments may vary, pain is often the factor that compels the patient to seek medical attention. Traumatic injury from sport is one cause of progressive chronic joint pain, particularly in the lower quarter. Recent studies have demonstrated the presence of peripheral and central sensitization mechanisms in different lower quadrant pain syndromes, such as lumbar spine related leg pain, osteoarthritis of the knee, and following acute injuries such as lateral ankle sprain and anterior cruciate ligament rupture. Proper management of lower quarter conditions should include assessment of balance and gait as increasing pain and chronicity may lead to altered gait patterns and falls. In addition, quantitative sensory testing may provide insight into pain mechanisms which affect management and prognosis of musculoskeletal conditions. Studies have demonstrated analgesic effects and modulation of spinal excitability with use of manual therapy techniques, with clinical outcomes of improved gait and functional ability. This paper will discuss the evidence which supports the use of manual therapy for lower quarter musculoskeletal dysfunction.

Commercially Available Low Probability of Intercept Radars and Non-Cooperative ELINT Receiver Capabilities

Science.gov (United States)

2014-09-01

3D Antenna Gain 0 dB Azimuth Accuracy 20°/quadrant 52 51. ELT/750 Receiver Figure 51: ELT/750 Receiver/processor...71]) The Itata ELINT system has been developed by Desarrollo de Tecnologia y Sistemas (DTS) Ltd. and is a high-sensitivity electronic... 3D Long Range Surveillance Radar. [Online]. Available: https://www.thalesgroup.com/en/worldwide/defence/smart-l- 3d - long-range-surveillance-radar

Switched-mode converters (one quadrant)

CERN Document Server

Barrade, P

2006-01-01

Switched-mode converters are DC/DC converters that supply DC loads with a regulated output voltage, and protection against overcurrents and short circuits. These converters are generally fed from an AC network via a transformer and a conventional diode rectifier. Switched-mode converters (one quadrant) are non-reversible converters that allow the feeding of a DC load with unipolar voltage and current. The switched-mode converters presented in this contribution are classified into two families. The first is dedicated to the basic topologies of DC/DC converters, generally used for low- to mid-power applications. As such structures enable only hard commutation processes, the main drawback of such topologies is high commutation losses. A typical multichannel evolution is presented that allows an interesting decrease in these losses. Deduced from this direct DC/DC converter, an evolution is also presented that allows the integration of a transformer into the buck and the buck–boost structure. This enables an int...

Right Lower Quadrant Abdominal Pain in a Patient with Prior Ventriculoperitoneal Shunting: Consider the Tip!

Directory of Open Access Journals (Sweden)

Petros Charalampoudis

2012-01-01

Full Text Available Introduction. Ventriculoperitoneal (VP shunting is the treatment of choice for nonobstructive hydrocephalus. In patients with such a device, right lower quadrant abdominal pain can puzzle the surgeon, posing a differential diagnostic problem among appendicitis, nonsurgical colicky pain, and primary shunt catheter tip infection. Treatment is different in either case. Presentation of Case. We hereby present a case of a young woman with prior ventriculoperitoneal shunt positioning who presented to our department with right lower quadrant abdominal pain. The patient underwent a 24-hour observation including a neurosurgery consult in order to exclude acute appendicitis and VP shunt tip infection. Twenty four hours later, the patient’s symptomatology improved, and she was discharged with the diagnosis of atypical colicky abdominal pain seeking a gastroenterologist consult. Discussion. This case supports that when a patient with prior VP shunting presents with right lower quadrant abdominal pain, differential diagnosis can be tricky for the surgeon. Conclusion. Apart from acute appendicitis, primary or secondary VP catheter tip infection must be considered because the latter can be disastrous.

Four-quadrant speed control circuit of DC servo motor using integrated voltage control method; Den`atsu sekibunchi seigyo wo mochoiita chokuryu dendoki no shishogen sokudo seigyo

Energy Technology Data Exchange (ETDEWEB)

Okui, H. [Osaka polytechnic College, Osaka (Japan); Irie, H. [Osaka Electro-Communication Univ., Osaka (Japan)

1996-08-20

The Two-Quadrant chopper is constructed by using smoothing reactor in common of the step-down chopper and step-up chopper of the DC chopper. Furthermore, since the circuit connected in bridge type by using these two groups has both of positive and negative voltage from DC source and can supplies the current from positive and negative directions for load, it is called in general as the Four-Quadrant chopper. As the Four-Quadrant chopper may supply and regenerate power, it works as power amplifier with high efficiency. In this paper, the speed control circuit of DC servo motor using Four-Quadrant integrated voltage control circuit is described. The speed control circuit is composed of simple circuits of one adder integrator and four hysteresis comparators. The Four-Quadrant speed control circuit has a DC motor speed feedback loop and a voltage feedback loop which connects with AC, it plays the Four-Quadrant speed control without current inspection. The speed control characteristics with no steady state error over four quadrants may be obtained, changing of the quadrant is smooth and transition response is rapid. 9 refs., 11 figs.

Recurrent Upper Quadrant Pain: A Fish Bone Secondary to Gastric Perforation and Liver Abscess

Directory of Open Access Journals (Sweden)

Hui Liang

2011-12-01

Full Text Available A 60-year-old male patient was admitted to our hospital for recurrent upper quadrant pain for 1 month. He had a past history of coronary artery disease. After admission, he repeatedly suffered from high-grade fever, chills and upper quadrant pain. Computed tomography (CT showed a round hypodense mass in the left lobe of the liver, approximately 2.7 × 2.2 cm in size, and a fish bone was confirmed by surgery in the left lobe of liver. The patient was cured completely after surgical removal of the fish bone and liver abscess. CT scan 1 month after discharge showed that the liver abscess had disappeared completely.

Virtual reality enhanced mannequin (VREM) that is well received by resuscitation experts.

Science.gov (United States)

Semeraro, Federico; Frisoli, Antonio; Bergamasco, Massimo; Cerchiari, Erga L

2009-04-01

The objective of this study was to test acceptance of, and interest in, a newly developed prototype of virtual reality enhanced mannequin (VREM) on a sample of congress attendees who volunteered to participate in the evaluation session and to respond to a specifically designed questionnaire. A commercial Laerdal HeartSim 4000 mannequin was developed to integrate virtual reality (VR) technologies with specially developed virtual reality software to increase the immersive perception of emergency scenarios. To evaluate the acceptance of a virtual reality enhanced mannequin (VREM), we presented it to a sample of 39 possible users. Each evaluation session involved one trainee and two instructors with a standardized procedure and scenario: the operator was invited by the instructor to wear the data-gloves and the head mounted display and was briefly introduced to the scope of the simulation. The instructor helped the operator familiarize himself with the environment. After the patient's collapse, the operator was asked to check the patient's clinical conditions and start CPR. Finally, the patient started to recover signs of circulation and the evaluation session was concluded. Each participant was then asked to respond to a questionnaire designed to explore the trainee's perception in the areas of user-friendliness, realism, and interaction/immersion. Overall, the evaluation of the system was very positive, as was the feeling of immersion and realism of the environment and simulation. Overall, 84.6% of the participants judged the virtual reality experience as interesting and believed that its development could be very useful for healthcare training. The prototype of the virtual reality enhanced mannequin was well-liked, without interfence by interaction devices, and deserves full technological development and validation in emergency medical training.

Virtual reality-based therapy for the treatment of balance deficits in patients receiving inpatient rehabilitation for traumatic brain injury.

Science.gov (United States)

Cuthbert, Jeffrey P; Staniszewski, Kristi; Hays, Kaitlin; Gerber, Don; Natale, Audrey; O'Dell, Denise

2014-01-01

To evaluate the feasibility and safety of utilizing a commercially available virtual reality gaming system as a treatment intervention for balance training. A randomized controlled trial in which assessment and analysis were blinded. An inpatient rehabilitation facility. Interventions included balance-based physical therapy using a Nintendo Wii, as monitored by a physical therapist, and receipt of one-on-one balance-based physical therapy using standard physical therapy modalities available for use in the therapy gym. Participants in the standard physical therapy group were found to have slightly higher enjoyment at mid-intervention, while those receiving the virtual reality-based balance intervention were found to have higher enjoyment at study completion. Both groups demonstrated improved static and dynamic balance over the course of the study, with no significant differences between groups. Correlational analyses suggest a relationship exists between Wii balance board game scores and BBS scores for measures taken beyond the baseline assessment. This study provides a modest level of evidence to support using commercially available VR gaming systems for the treatment of balance deficits in patients with a primary diagnosis of TBI receiving inpatient rehabilitation. Additional research of these types of interventions for the treatment of balance deficits is warranted.

Design and development of bipolar 4-quadrant switch-mode power converter for superconducting magnets

International Nuclear Information System (INIS)

Yashwant Kumar; Thakur, S.K.; Ghosh, M.K.; Tiwari, T.P.; De, Anirban; Kumari, S.; Saha, S.

2011-01-01

A uniform zero crossing magnetic field in a magnet can be achieved by using bipolar power converter with four quadrant operation. A high current bipolar switch-mode power converter (rated ±27 V max , ±7V flat top, ±300A, 100 ppm) has been designed and developed indigenously at VECC Kolkata. Four quadrants operation is accomplished by using power IGBTs in an H-bridge configuration with switching frequency around 20 kHz. The switch-mode power converter is used because of high dynamic response, low output ripple, high efficiency and low input current harmonics. In this paper, circuit topology, function of system components and key system specifications of high current bipolar switch mode power converter is discussed. (author)

THE QUADRANTS METHOD TO ESTIMATE QUANTITATIVE VARIABLES IN MANAGEMENT PLANS IN THE AMAZON

Directory of Open Access Journals (Sweden)

Gabriel da Silva Oliveira

2015-12-01

Full Text Available This work aimed to evaluate the accuracy in estimates of abundance, basal area and commercial volume per hectare, by the quadrants method applied to an area of 1.000 hectares of rain forest in the Amazon. Samples were simulated by random and systematic process with different sample sizes, ranging from 100 to 200 sampling points. The amounts estimated by the samples were compared with the parametric values recorded in the census. In the analysis we considered as the population all trees with diameter at breast height equal to or greater than 40 cm. The quadrants method did not reach the desired level of accuracy for the variables basal area and commercial volume, overestimating the observed values recorded in the census. However, the accuracy of the estimates of abundance, basal area and commercial volume was satisfactory for applying the method in forest inventories for management plans in the Amazon.

Current radiological strategies for the assessment of right lower quadrant abdominal pain

Directory of Open Access Journals (Sweden)

Pumersha Naidoo

2014-12-01

Full Text Available Right lower quadrant abdominal pain is a common clinical entity. Imaging and the radiologistplay an integral role in achieving a diagnosis, so guiding prompt management of patients.This review discusses the spectrum of pathology and imaging findings, and highlights and contrasts the preferred imaging modalities in different subsets of patients.

A POSSIBLE EXTENSION OF THE SCUTUM-CENTAURUS ARM INTO THE OUTER SECOND QUADRANT

Energy Technology Data Exchange (ETDEWEB)

Sun, Yan; Xu, Ye; Yang, Ji; Li, Fa-Cheng; Du, Xin-Yu; Zhang, Shao-Bo; Zhou, Xin, E-mail: yansun@pmo.ac.cn [Purple Mountain Observatory and Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, Nanjing 210008 (China)

2015-01-10

Combining H I data from the Canadian Galactic Plane Survey and CO data from the Milky Way Imaging Scroll Painting project, we have identified a new segment of a spiral arm between Galactocentric radii of 15 and 19 kpc that apparently lies beyond the Outer Arm in the second Galactic quadrant. Over most of its length, the arm is 400-600 pc thick in z. The new arm appears to be the extension of the distant arm recently discovered by Dame and Thaddeus as well as the Scutum-Centaurus Arm into the outer second quadrant. Our current survey identified a total of 72 molecular clouds with masses on the order of 10{sup 2}-10{sup 4} M {sub ☉} that probably lie in the new arm. When all of the available data from the CO molecular clouds are fit, the best-fitting spiral model gives a pitch angle of 9.°3 ± 0.°7.

Dual pathology in a patient with right lower quadrant pain.

Science.gov (United States)

Deutsch, Gary B; Sathyanarayana, Sandeep Anantha; Nicastro, Jeffrey; Molmenti, Ernesto; Coppa, Gene; Rubach, Eugene; Friedman, Barak

2012-09-01

Meckel diverticula are remnants of the omphalomesenteric duct. They have 2% incidence in the general population, are usually asymptomatic, and tend to be diagnosed incidentally. The generally held principle had been that asymptomatic cases do not require resection, as exemplified by a 2008 systematic review of over 200 studies. However, a recent series reported an increased risk of malignancies, and recommended mandatory resection. We present a case of Meckel diverticulitis with concurrent infiltrative appendiceal carcinoid in a patient with right lower quadrant pain.

Patient Satisfaction with Virtual Obstetric Care.

Science.gov (United States)

Pflugeisen, Bethann Mangel; Mou, Jin

2017-07-01

Introduction The importance of patient satisfaction in US healthcare is increasing, in tandem with the advent of new patient care modalities, including virtual care. The purpose of this study was to compare the satisfaction of obstetric patients who received one-third of their antenatal visits in videoconference ("Virtual-care") compared to those who received 12-14 face-to-face visits in-clinic with their physician/midwife ("Traditional-care"). Methods We developed a four-domain satisfaction questionnaire; Virtual-care patients were asked additional questions about technology. Using a modified Dillman method, satisfaction surveys were sent to Virtual-care (N = 378) and Traditional-care (N = 795) patients who received obstetric services at our institution between January 2013 and June 2015. Chi-squared tests of association, t-tests, logistic regression, and ANOVA models were used to evaluate differences in satisfaction and self-reported demographics between respondents. Results Overall satisfaction was significantly higher in the Virtual-care cohort (4.76 ± 0.44 vs. 4.47 ± 0.59; p Virtual-care selection (OR = 2.4, 95% CI: 1.5-3.8; p Virtual-care respondents was not significantly impacted by the incorporation of videoconferencing, Doppler, and blood pressure monitoring technology into their care. The questionnaire demonstrated high internal consistency as measured by domain-based correlations and Cronbach's alpha. Discussion Respondents from both models were highly satisfied with care, but those who had selected the Virtual-care model reported significantly higher mean satisfaction scores. The Virtual-care model was selected by significantly more women who already have children than those experiencing pregnancy for the first time. This model of care may be a reasonable alternative to traditional care.

Quadrant I RCRA Facility Investigation Work Plan

International Nuclear Information System (INIS)

1990-01-01

The objective of this Facility Investigation (FRI) at the Portsmouth Gaseous Diffusion Plant (PORTS) is to acquire, analyze and interpret data which will: (1) characterize the environmental setting including ground water, surface water and sediment, soil and air; (2) define and characterize sources of contamination; (3) characterize the vertical and horizontal extent and degree of contamination of the environment; (4) assess the risk to human health and the environment resulting from possible exposure to contaminants; and, (5) support the Corrective Measures Study (CMS) which will follow the RFI. Investigations to characterize the environmental setting, sources of contamination, and vertical and horizontal extent and degree of contamination will be conducted relative to individual potential sources which have been identified in the Quadrant I Description of Current Conditions. These unit investigations will follow the systematic approach which is outlined below

Estimating and correcting the amplitude radiation pattern of a virtual source

OpenAIRE

Van der Neut, J.; Bakulin, A.

2009-01-01

In the virtual source (VS) method we crosscorrelate seismic recordings at two receivers to create a new data set as if one of these receivers were a virtual source and the other a receiver. We focus on the amplitudes and kinematics of VS data, generated by an array of active sources at the surface and recorded by an array of receivers in a borehole. The quality of the VS data depends on the radiation pattern of the virtual source, which in turn is controlled by the spatial aperture of the sur...

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 have created a wide interest in virtual reality. In the field of computer music, the term “virtual musical instruments” has been used for a long time to describe software simulations, extensions of existing musical instruments......, and ways to control them with new interfaces for musical expression. Virtual reality musical instruments (VRMIs) that include a simulated visual component delivered via a head-mounted display or other forms of immersive visualization have not yet received much attention. In this article, we present a field...

Diagnostic accuracy in virtual dermatopathology

DEFF Research Database (Denmark)

Mooney, E.; Kempf, W.; Jemec, G.B.E.

2012-01-01

Background Virtual microscopy is used for teaching medical students and residents and for in-training and certification examinations in the United States. However, no existing studies compare diagnostic accuracy using virtual slides and photomicrographs. The objective of this study was to compare...... diagnostic accuracy of dermatopathologists and pathologists using photomicrographs vs. digitized images, through a self-assessment examination, and to elucidate assessment of virtual dermatopathology. Methods Forty-five dermatopathologists and pathologists received a randomized combination of 15 virtual...... slides and photomicrographs with corresponding clinical photographs and information in a self-assessment examination format. Descriptive data analysis and comparison of groups were performed using a chi-square test. Results Diagnostic accuracy in dermatopathology using virtual dermatopathology...

Supporting document for the SW Quadrant Historical Tank Content Estimate for U-Tank Farm

International Nuclear Information System (INIS)

Brevick, C.H.; Gaddis, L.A.; Johnson, E.D.

1994-06-01

This Supporting Document provides historical characterization information gathered on U-Tank Farm, such as historical waste transfer and level data, tank physical information, temperature data, sampling data, and drywell and liquid observation well data for Historical Tank Content Estimate of the SW Quadrant at the Hanford 200 West Area

Supporting Document for the SW Quadrant Historical Tank Content Estimate for SX-Tank Farm

International Nuclear Information System (INIS)

Brevick, C.H.; Gaddis, L.A.; Johnson, E.D.

1994-06-01

This Supporting Document provides historical characterization information gathered on SX-Tank Farm, such as historical waste transfer and level data, tank physical information, temperature data, sampling data, and drywell and liquid observation well data for Historical Tank Content Estimate of the SW Quadrant at the Hanford 200 West Area

Differential impact of partial cortical blindness on gaze strategies when sitting and walking - an immersive virtual reality study.

Science.gov (United States)

Iorizzo, Dana B; Riley, Meghan E; Hayhoe, Mary; Huxlin, Krystel R

2011-05-25

The present experiments aimed to characterize the visual performance of subjects with long-standing, unilateral cortical blindness when walking in a naturalistic, virtual environment. Under static, seated testing conditions, cortically blind subjects are known to exhibit compensatory eye movement strategies. However, they still complain of significant impairment in visual detection during navigation. To assess whether this is due to a change in compensatory eye movement strategy between sitting and walking, we measured eye and head movements in subjects asked to detect peripherally-presented, moving basketballs. When seated, cortically blind subjects detected ∼80% of balls, while controls detected almost all balls. Seated blind subjects did not make larger head movements than controls, but they consistently biased their fixation distribution towards their blind hemifield. When walking, head movements were similar in the two groups, but the fixation bias decreased to the point that fixation distribution in cortically blind subjects became similar to that in controls - with one major exception: at the time of basketball appearance, walking controls looked primarily at the far ground, in upper quadrants of the virtual field of view; cortically blind subjects looked significantly more at the near ground, in lower quadrants of the virtual field. Cortically blind subjects detected only 58% of the balls when walking while controls detected ∼90%. Thus, the adaptive gaze strategies adopted by cortically blind individuals as a compensation for their visual loss are strongest and most effective when seated and stationary. Walking significantly alters these gaze strategies in a way that seems to favor walking performance, but impairs peripheral target detection. It is possible that this impairment underlies the experienced difficulty of those with cortical blindness when navigating in real life. Copyright © 2011 Elsevier Ltd. All rights reserved.

Geometric quasi-similarity: Case of nozzles with quadrant-shaped inlet

Czech Academy of Sciences Publication Activity Database

Tesař, Václav

Roč. 248, September (2016), s. 246-256 ISSN 0924-4247 R&D Projects: GA ČR GA13-23046S Institutional support: RVO:61388998 Keywords : nozzles * local geometric similarity * quasi-similarity * reynolds number * euler number * quadrant nozzles Subject RIV: BK - Fluid Dynamics Impact factor: 2.499, year: 2016 http://ac.els-cdn.com/S0924424716303399/1-s2.0-S0924424716303399-main.pdf?_tid=79a1397c-6e8d-11e6-893f-00000aacb361&acdnat=1472546639_01cebf4490123f8e5db56d9c4cda5fd5

Preceptor Perceptions of Virtual Quality Assurance Experiential Site Visits.

Science.gov (United States)

Clarke, Cheryl L; Schott, Kathryn A; Arnold, Austin D

2018-05-01

Objective. To determine preceptor perceptions of the value of experiential quality assurance site visits between virtual and onsite visits, and to gauge preceptor opinions of the optimal method of site visits based on the type of visit received. Methods. Site visits (12 virtual and 17 onsite) were conducted with 29 APPE sites located at least 200 miles from campus. Participating preceptors were invited to complete an online post-visit survey adapted from a previously validated and published survey tool measuring preceptor perceptions of the value of traditional onsite visits. Results. Likert-type score averages for survey questions ranged from 4.2 to 4.6 in the virtual group and from 4.3 to 4.7 in the onsite group. No statistically significant difference was found between the two groups. Preceptors were more inclined to prefer the type of visit they received. Preceptors receiving onsite visits were also more likely to indicate no visit type preference. Conclusion. Preceptors perceived value from both onsite and virtual site visits. Preceptors who experienced virtual site visits highly preferred that methodology. This study suggests that virtual site visits may be a viable alternative for providing experiential quality assurance site visits from a preceptor's perspective.

Virtual Morris task responses in individuals in an abstinence phase from alcohol.

Science.gov (United States)

Ceccanti, Mauro; Coriale, Giovanna; Hamilton, Derek A; Carito, Valentina; Coccurello, Roberto; Scalese, Bruna; Ciafrè, Stefania; Codazzo, Claudia; Messina, Marisa Patrizia; Chaldakov, George N; Fiore, Marco

2018-02-01

The present study was aimed at examining spatial learning and memory, in 33 men and 12 women with alcohol use disorder (AUD) undergoing ethanol detoxification, by using a virtual Morris task. As controls, we recruited 29 men and 10 women among episodic drinkers without a history of alcohol addiction or alcohol-related diseases. Elevated latency to the first movement in all trials was observed only in AUD persons; furthermore, control women had longer latencies compared with control men. Increased time spent to reach the hidden platform in the learning phase was found for women of both groups compared with men, in particular during trial 3. As predicted, AUD persons (more evident in men) spent less time in the target quadrant during the probe trial; however, AUD women had longer latencies to reach the platform in the visible condition during trials 6 and 7 that resulted in a greater distance moved. As for the probe trial, men of both groups showed increased virtual locomotion compared with the women of both groups. The present investigation confirms and extends previous studies showing (i) different gender responses in spatial learning tasks, (ii) some alterations due to alcohol addiction in virtual spatial learning, and (iii) differences between AUD men and AUD women in spatial-behaviour-related paradigms.

Four quadrant parallel peripheral screw fixation for displaced femoral neck fractures in elderly patients

Directory of Open Access Journals (Sweden)

Bhava RJ Satish

2013-01-01

Conclusion: Closed reduction and cannulated cancellous screw fixation gives satisfactory functional results in large group of elderly patients. The four quadrant parallel peripheral (FQPP screw fixation technique gives good stability, allows controlled collapse, avoids fixation failure and achieves predictable bone healing in displaced femoral neck fracture in patients ≥50 years of age.

Four quadrant transversus abdominis plane block and continuous transversus abdominis plane analgesia: a 3-year prospective audit in 124 patients.

Science.gov (United States)

Niraj, G; Kelkar, Aditi; Hart, Elaine; Kaushik, Vipul; Fleet, Danny; Jameson, John

2015-11-01

Transversus abdominis plane (TAP) blocks have been reported to be an effective method of providing analgesia after abdominal surgery. To perform a prospective audit on the effectiveness of a novel technique of providing continuous transversus abdominis plane (TAP) analgesia in patients undergoing emergency and elective abdominal surgery. Prospective single center audit over a 3-year period. University hospital. One hundred twenty-four American Society of Anesthesiologists I to IV adult patients presenting for elective as well as emergency abdominal surgery in whom epidural analgesia was contraindicated or refused. Four quadrant TAP blocks and continuous TAP analgesia. Numerical rating scale pain scores at rest and on coughing, nausea scores, satisfaction scores, complications, frequency of analgesia failure, therapeutic failure with continuous TAP analgesia and opioid consumption. One hundred twenty-four patients who received continuous TAP analgesia were audited. This included 34 patients for elective open surgery, 36 patients for emergency laparotomy, and 54 patients who underwent elective laparoscopic colorectal surgery. Surgical incision was within the dermatomal limit of the block in 70% of the patients (88/124). Therapeutic failure with the technique was 10%. Frequency of analgesic failure over the 48-hour period was none in 39% and below 5 episodes in 57%. Four quadrant transversus abdominis plane blocks and continuous TAP analgesia is an effective technique for providing postoperative analgesia after abdominal surgery. It has the potential to be used as a sole analgesic technique when the surgical incision is within its dermatomal limit. Copyright © 2015 Elsevier Inc. All rights reserved.

Estimating and correcting the amplitude radiation pattern of a virtual source

NARCIS (Netherlands)

Van der Neut, J.; Bakulin, A.

2009-01-01

In the virtual source (VS) method we crosscorrelate seismic recordings at two receivers to create a new data set as if one of these receivers were a virtual source and the other a receiver. We focus on the amplitudes and kinematics of VS data, generated by an array of active sources at the surface

Message Received: Virtual Ethnography in Online Message Boards

Directory of Open Access Journals (Sweden)

Kevin F. Steinmetz

2012-02-01

Full Text Available As the Internet begins to encapsulate more people within online communities, it is important that the social researcher have well-rounded ethnographic methodologies for observing these phenomena. This article seeks to contribute to methodology by detailing and providing insights into three specific facets of virtual ethnography that need attention: space and time, identity and authenticity, and ethics. Because the Internet is a globalized and instantaneous medium where space and time collapse, identity becomes more playful, and ethics become more tenuous; understanding these aspects is crucial to the study of online social groups. A second focus of this article is to apply these notions to the study of online message boards—a frequently used medium for online communication that is frequently overlooked by methodologists.

A Clinical Observation of Ultrasonographic Diagnosis on Right upper Quadrant Pain

International Nuclear Information System (INIS)

Lee, Suck Hong; Moon, T. Y.; Chang, H. Y.; Kim, B. S.

1982-01-01

The author analyzed a total of 127 cases of ultrasonography studied for evaluation of the causes of right upper quadrant pain during ten months from Feb.1 to Nov. 30 1981, at the department of radiology, Busan national university and St. Benedict hospital. The results were as follows: 1. ultrasonographic findings of the total of 127 cases are normal in 41(32.3%) cases, and abnormal in 86(67.6%) cases. 2. Clinical diagnosis of normal ultrasonographic cases is unknown in 15(36.6%) cases, hepatitis in 10(24.3%) cases, pancreatitis in 6(14.6%) case,enterocolitis in 5(12.1%) cases, acute gastritis in 3(7.5%), acute pyelonephritis in 1(2.4%) case, and clonorchiasis in 1(2.4%) case. 3. Pathological diagnosis of 50 cases out of 86 cases of abnormal ultrasonography is GB stone in 36(72.0%) cases, pancreatic cancer in 5(10.0%) cases, hepatoma in 3(6.0%) cases, CBD stone in 4(8.0%) cases, pancreatic pseudocyst in 1(12.9%) case and liver abscess in 1(2.0%) case. 4. Diagnostic accuracy of ultrasonography of GB stone was 91.7%, false positive 2.8% and false negative 6.6%. 5. Ultrasonography has the advantage of noninvasiveness and easy performance, but the diagnostic accuracy of ultrasonography alone was low. Ultrasonography is considered as a good screening and complementary method for evaluation of right upper quadrant pain

A Clinical Observation of Ultrasonographic Diagnosis on Right upper Quadrant Pain

Energy Technology Data Exchange (ETDEWEB)

Lee, Suck Hong; Moon, T. Y.; Chang, H. Y.; Kim, B. S. [Pusan National University College of Medicine, Busan (Korea, Republic of)

1982-12-15

The author analyzed a total of 127 cases of ultrasonography studied for evaluation of the causes of right upper quadrant pain during ten months from Feb.1 to Nov. 30 1981, at the department of radiology, Busan national university and St. Benedict hospital. The results were as follows: 1. ultrasonographic findings of the total of 127 cases are normal in 41(32.3%) cases, and abnormal in 86(67.6%) cases. 2. Clinical diagnosis of normal ultrasonographic cases is unknown in 15(36.6%) cases, hepatitis in 10(24.3%) cases, pancreatitis in 6(14.6%) case,enterocolitis in 5(12.1%) cases, acute gastritis in 3(7.5%), acute pyelonephritis in 1(2.4%) case, and clonorchiasis in 1(2.4%) case. 3. Pathological diagnosis of 50 cases out of 86 cases of abnormal ultrasonography is GB stone in 36(72.0%) cases, pancreatic cancer in 5(10.0%) cases, hepatoma in 3(6.0%) cases, CBD stone in 4(8.0%) cases, pancreatic pseudocyst in 1(12.9%) case and liver abscess in 1(2.0%) case. 4. Diagnostic accuracy of ultrasonography of GB stone was 91.7%, false positive 2.8% and false negative 6.6%. 5. Ultrasonography has the advantage of noninvasiveness and easy performance, but the diagnostic accuracy of ultrasonography alone was low. Ultrasonography is considered as a good screening and complementary method for evaluation of right upper quadrant pain

THERE ARE NO STARLESS MASSIVE PROTO-CLUSTERS IN THE FIRST QUADRANT OF THE GALAXY

Energy Technology Data Exchange (ETDEWEB)

Ginsburg, A.; Bally, J.; Battersby, C. [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States); Bressert, E. [European Southern Observatory, Karl Schwarzschild str. 2, D-85748 Garching bei Muenchen (Germany)

2012-10-20

We search the {lambda} = 1.1 mm Bolocam Galactic Plane Survey for clumps containing sufficient mass to form {approx}10{sup 4} M{sub Sun} star clusters. Eighteen candidate massive proto-clusters are identified in the first Galactic quadrant outside of the central kiloparsec. This sample is complete to clumps with mass M{sub clump} > 10{sup 4} M{sub Sun} and radius r {approx}< 2.5 pc. The overall Galactic massive cluster formation rate is CFR(M{sub cluster} > 10{sup 4}) {approx}<5 Myr{sup -1}, which is in agreement with the rates inferred from Galactic open clusters and M31 massive clusters. We find that all massive proto-clusters in the first quadrant are actively forming massive stars and place an upper limit of {tau}{sub starless} < 0.5 Myr on the lifetime of the starless phase of massive cluster formation. If massive clusters go through a starless phase with all of their mass in a single clump, the lifetime of this phase is very short.

The diagnostic role of US in patients with right lower quadrant abdominal pain

Energy Technology Data Exchange (ETDEWEB)

Lee, Sheen Woo; Lee, Jeong Kyong; Baek, Seung Yon; Kang, Byung Chul; Lee, Sun Wha [Ewha Womans Univ. College of Medicine, Seoul (Korea, Republic of)

2000-12-01

To determine the frequency with which ultrasonography (US) provides a correct diagnosis and suggests appropriate guidance for the treatment of patients with right lower quadrant abdominal pain. During an 11-month period, US was consecutively performed in 84 patients who were presented with right lower quadrant abdominal pain. In the 76 [M:F = 16:60, age range 14-87 (mean, 41) years] who formed the study population, final diagnoses were made surgically or clinically. For US, a 5-7-MHz convex-array, 4-MHz vector-array, and/or 7-MHz linear-array transducer was used, according to the patient's body habitus. To determine how often our US reports had provided a correct diagnosis and suggested appropriate guidance for surgical or medical treatment, and to calculate their diagnostic value, the reports were retrospectively compared with final diagnoses. US diagnoses were acute appendicitis in 40 patients (53%), diseases other than this in 25 patients (33%), and no abnormality in 11 (14%). In 38 of the 40 patients (95%), the diagnosis of acute appendicitis was surgically confirmed as correct, and for other diseases, diagnoses based on the findings of US proved to be correct in 21 of 25 patients (84%). Overall, diagnoses was correct in 67 (88%). As regards appropriate guidance for treatment, 46 (61%) and 30 (39%) patients were diagnosed by US to have surgical and medical diseases, respectively. In 44 of the 46 (96%), it was confirmed guidance was appropriate, and for the 30 with medical disease, this was so in all but one case (97%). Overall, the treatment plan was appropriate in 72 patients (95%). Our study revealed that US was able to provide a correct diagnosis in 88% of patients with right lower quadrant abdominal pain, and in 95% of these, the treatment plan suggested was appropriate. US is, therefore, a valuable screening tool in the diagnosis and therapeutic guidance of such patients.

Windowed SHE-PWM of Interleaved Four-Quadrant Converters for Resonance Suppression in Traction Power Supply Systems

DEFF Research Database (Denmark)

Song, Kejian; Konstantinou, Georgios; Mingli, Wu

2017-01-01

AC electric locomotives that use a number of interleaved four-quadrant converters generate high-frequency switching harmonics which may stimulate certain resonances in traction power supply systems (TPSSs). A windowed selective harmonic elimination pulse-width modulation (SHE-PWM) method...

Four Quadrants Integrated Transformers for Dual-input Isolated DC-DC Converters

DEFF Research Database (Denmark)

Ouyang, Ziwei; Zhang, Zhe; Andersen, Michael A. E.

2012-01-01

A common limitation of power coupling effect in some known multiple-input dc-dc converters has been addressed in many literatures. In order to overcome this limitation, a new concept for decoupling the primary windings in the integrated multiple-winding transformers based on 3-dimensional (3D...... perpendicular primary windings, a name of “four quadrants integrated transformers” (FQIT) is therefore given to the proposed construction. Since the two primary windings are uncoupled, the FQIT allows the two input power stages to transfer the energy into the output load simultaneously or at any...

VirtualSpace: A vision of a machine-learned virtual space environment

Science.gov (United States)

Bortnik, J.; Sarno-Smith, L. K.; Chu, X.; Li, W.; Ma, Q.; Angelopoulos, V.; Thorne, R. M.

2017-12-01

Space borne instrumentation tends to come and go. A typical instrument will go through a phase of design and construction, be deployed on a spacecraft for several years while it collects data, and then be decommissioned and fade into obscurity. The data collected from that instrument will typically receive much attention while it is being collected, perhaps in the form of event studies, conjunctions with other instruments, or a few statistical surveys, but once the instrument or spacecraft is decommissioned, the data will be archived and receive progressively less attention with every passing year. This is the fate of all historical data, and will be the fate of data being collected by instruments even at the present time. But what if those instruments could come alive, and all be simultaneously present at any and every point in time and space? Imagine the scientific insights, and societal gains that could be achieved with a grand (virtual) heliophysical observatory that consists of every current and historical mission ever deployed? We propose that this is not just fantasy but is imminently doable with the data currently available, with the present computational resources, and with currently available algorithms. This project revitalizes existing data resources and lays the groundwork for incorporating data from every future mission to expand the scope and refine the resolution of the virtual observatory. We call this project VirtualSpace: a machine-learned virtual space environment.

Realistic Visualization of Virtual Views

DEFF Research Database (Denmark)

Livatino, Salvatore

2005-01-01

that can be impractical and sometime impossible. In addition, the artificial nature of data often makes visualized virtual scenarios not realistic enough. Not realistic in the sense that a synthetic scene is easy to discriminate visually from a natural scene. A new field of research has consequently...... developed and received much attention in recent years: Realistic Virtual View Synthesis. The main goal is a high fidelity representation of virtual scenarios while easing modeling and physical phenomena simulation. In particular, realism is achieved by the transfer to the novel view of all the physical...... phenomena captured in the reference photographs, (i.e. the transfer of photographic-realism). An overview of most prominent approaches in realistic virtual view synthesis will be presented and briefly discussed. Applications of proposed methods to visual survey, virtual cinematography, as well as mobile...

Design of DGPS Receiver Based on the Net of VRS

Directory of Open Access Journals (Sweden)

Yun XU

2014-02-01

Full Text Available To improve the positioning accuracy of the GPS system, the differential technology based on real time kinematic is utilized. Comparing with the conventional differential technology, the differential technology based on the virtual reference station can minimize the size of the rover station which is of great significance for the small system such as the mini-type unmanned vehicle, smart ammunitions and so on. Due to the high cost of the GPS receivers in the market which can’t be redeveloped and the limitation of their interface, it is not suitable for the application of the embedded system. In this paper, the receiver based on the aforementioned method is proposed to realize the real time differential positioning. Firstly, the concept of differential positioning based on real time kinematic is explained. Next, the composition of the virtual reference system and its working principle are introduced. And then, the design of differential GPS receiver based on the virtual reference system for rover station is illustrated. Finally, from the repeatability test, the result shows that by means of getting the differential corrections from the virtual reference station, the designed differential GPS receiver can correct the errors caused by ionosphere, troposphere and atmospheric refraction. Moreover, it can improve the positioning accuracy to centimeter-level. With low cost, small size and convertibility of the interface of the designed differential GPS receiver according to the embedded system, it will be popular in the future market.

18 CFR 38.2 - Incorporation by reference of North American Energy Standards Board Wholesale Electric Quadrant...

Science.gov (United States)

2010-04-01

... reference of North American Energy Standards Board Wholesale Electric Quadrant standards. 38.2 Section 38.2 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY... UTILITIES § 38.2 Incorporation by reference of North American Energy Standards Board Wholesale Electric...

Tracking Changes in Cardiac Output: Statistical Considerations on the 4-Quadrant Plot and the Polar Plot Methodology.

Science.gov (United States)

Saugel, Bernd; Grothe, Oliver; Wagner, Julia Y

2015-08-01

When comparing 2 technologies for measuring hemodynamic parameters with regard to their ability to track changes, 2 graphical tools are omnipresent in the literature: the 4-quadrant plot and the polar plot recently proposed by Critchley et al. The polar plot is thought to be the more advanced statistical tool, but care should be taken when it comes to its interpretation. The polar plot excludes possibly important measurements from the data. The polar plot transforms the data nonlinearily, which may prevent it from being seen clearly. In this article, we compare the 4-quadrant and the polar plot in detail and thoroughly describe advantages and limitations of each. We also discuss pitfalls concerning the methods to prepare the researcher for the sound use of both methods. Finally, we briefly revisit the Bland-Altman plot for the use in this context.

Mast Quadrant-assisted Minimally Invasive Modified Transforaminal Lumbar Interbody Fusion: Single Incision Versus Double Incision

Directory of Open Access Journals (Sweden)

Xin-Lei Xia

2015-01-01

Full Text Available Background: The concept of minimally invasive techniques is to make every effort to reduce tissue damage. Certainly, reducing skin incision is an important part of these techniques. This study aimed to investigate the clinical feasibility of Mast Quadrant-assisted modified transforaminal lumbar interbody fusion (TLIF with a small single posterior median incision. Methods: During the period of March 2011 to March 2012, 34 patients with single-segment degenerative lumbar disease underwent the minimally invasive modified TLIF assisted by Mast Quadrant with a small single posterior median incision (single incision group. The cases in this group were compared to 37 patients with single-segment degenerative lumbar disease in the double incision group. The perioperative conditions of patients in these two groups were statistically analyzed and compared. The Oswestry Disability Index (ODI scores, Visual Analog Scale (VAS scores, and sacrospinalis muscle damage evaluation indicators before operation and 3, 12 months postoperation were compared. Results: A total of 31 and 35 cases in the single incision and double incision groups, respectively, completed at least 12 months of systemic follow-up. The differences in perioperative conditions between the two groups were not statistically significant. The incision length of the single incision group was significantly shorter than that of the double incision group (P < 0.01. The ODI and VAS scores of patients in both groups improved significantly at 3 and 12 months postoperation. However, these two indicators at 3 and 12 months postoperation and the sacrospinalis muscle damage evaluation indicators at 3 months postoperation did not differ significantly between the two groups (P ≥ 0.05. Conclusions: Mast Quadrant-assisted modified TLIF with a small single posterior median incision has excellent clinical feasibility compared to minimally invasive TLIF with a double paramedian incision.

High performance control strategy for single-phase three-level neutral-point-clamped traction four-quadrant converters

DEFF Research Database (Denmark)

Kejian, Song; Konstantinou, Georgios; Jing, Li

2017-01-01

Operational data from Chinese railways indicate a number of challenges for traction four-quadrant converter (4QC) control including low-order voltage and current harmonics and reference tracking. A control strategy for a single-phase three-level neutral-point-clamped 4QC employed in the electric...

Effect of oral IQoro R and palatal plate training in post-stroke, four-quadrant facial dysfunction and dysphagia: A comparison study.

Science.gov (United States)

Hägg, Mary; Tibbling, Lita

2015-09-01

Training with either a palatal plate (PP) or an oral IQoro(R) screen (IQS) in patients with longstanding facial dysfunction and dysphagia after stroke can significantly improve facial activity (FA) in all four facial quadrants as well as swallowing capacity (SC). Improvements remained at late follow-up. The training modalities did not significantly differ in ameliorating facial dysfunction and dysphagia in these patients. However, IQS training has practical and economic advantages over PP training. This study compared PP and oral IQS training in terms of (i) effect on four-quadrant facial dysfunction and dysphagia after a first-ever stroke, and (ii) whether the training effect persisted at late follow-up. Patients were included during two periods; 13 patients in 2005-2008 trained with a PP, while 18 patients in 2009-2012 trained with an IQS. Four-quadrant facial dysfunction was assessed with an FA test and swallowing dysfunction with a SC test: before and after a 3-month training period and at late follow-up. FA and SC significantly improved (p stroke incidence and the start of training was long or short.

Factors influencing presence in virtual worlds.

Science.gov (United States)

Chow, Meyrick C M

2012-01-01

Virtual worlds are showing potential as an effective platform for a variety of activities, including learning. The concept of presence (the sensation of "being there" in a mediated environment) has received substantial attention from the virtual reality community, and the effectiveness of virtual worlds has often been linked to the feelings of presence reported by their users. The present study examined the effects of attitude and perceived ease of use on sense of presence in Second Life, which is one of the most known and used virtual worlds. Based on data from a survey of 206 nursing students, hypotheses are empirically tested. Findings suggest that users' attitude toward using Second Life and their perceived ease of use of it have a positive effect on their sense of presence in the virtual environment. This study advances our understanding of factors influencing presence in virtual worlds.

Photo-Realistic Image Synthesis and Virtual Cinematography

DEFF Research Database (Denmark)

Livatino, Salvatore

2005-01-01

Realistic Virtual View Synthesis is a new field of research that has received increasing attention in recent years. It is strictly related to the grown 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 is then gaining consensus...

Supporting document for the north east quadrant historical tank content estimate report for AX-tank farm

International Nuclear Information System (INIS)

Brevick, C.H.; Gaddis, L.A.; Walsh, A.C.

1994-06-01

This Supporting Document provides historical in-depth characterization information gathered in AX-Tank Farm, such as historical waste transfer and level data, tank physical information, temperature data, sampling data, and drywell and liquid observation well data for Historical Tank Content Estimate Report of the NE Quadrant and the Hanford 200 East Areas

Supporting document for the north east quadrant historical tank content estimate report for C-Tank Farm

International Nuclear Information System (INIS)

Brevick, C.H.; Gaddis, L.A.; Walsh, A.C.

1994-06-01

This Supporting Document provides historical in-depth characterization information gathered on C-Tank Farm, such as historical waste transfer and level data, tank physical information, temperature data, sampling data, and drywell and liquid observation well data for Historical Tank Content Estimate Report of the NE Quadrant and the Hanford 200 East Areas

Caudal Edge of the Liver in the Right Upper Quadrant (RUQ View Is the Most Sensitive Area for Free Fluid on the FAST Exam

Directory of Open Access Journals (Sweden)

Viveta Lobo

2017-02-01

Full Text Available Introduction: The focused assessment with sonography in trauma (FAST exam is a critical diagnostic test for intraperitoneal free fluid (FF. Current teaching is that fluid accumulates first in Morison’s pouch. The goal of this study was to evaluate the “sub-quadrants” of traditional FAST views to determine the most sensitive areas for FF accumulation. Methods: We analyzed a retrospective cohort of all adult trauma patients who had a recorded FAST exam by emergency physicians at a Level I trauma center from January 2012 – June 2013. Ultrasound fellowship-trained faculty with three emergency medicine residents reviewed all FAST exams. We excluded studies if they were incomplete, of poor image quality, or with incorrect medical record information. Positive studies were assessed for FF localization, comparing the traditional abdominal views and on a sub-quadrant basis: right upper quadrant (RUQ1 - hepatodiaphragmatic; RUQ2 - Morison’s pouch; RUQ3 - caudal liver edge and superior paracolic gutter; left upper quadrant (LUQ1 - splenic-diaphragmatic; LUQ2 - spleno-renal; LUQ3 – around inferior pole of kidney; suprapubic area (SP1 - bilateral to bladder; SP2 - posterior to bladder; SP3 – posterior to uterus (females. FAST results were confirmed by chart review of computed tomography results or operative findings. Results: Of the included 1,008 scans, 48 (4.8% were positive. The RUQ was the most positive view with 32/48 (66.7% positive. In the RUQ sub-quadrant analysis, the most positive view was the RUQ3 with 30/32 (93.8% positive. Conclusion: The RUQ is most sensitive for FF assessment, with the superior paracolic gutter area around the caudal liver edge (RUQ3 being the most positive sub-quadrant within the RUQ. [West J Emerg Med. 2017;18(2270-280.

A CLASS OF DISTRIBUTION-FREE TESTS FOR INDEPENDENCE AGAINST POSITIVE QUADRANT DEPENDENCE

Directory of Open Access Journals (Sweden)

Parameshwar V Pandit

2014-02-01

Full Text Available A class of distribution-free tests based on convex combination of two U-statistics is considered for testing independence against positive quadrant dependence. The class of tests proposed by Kochar and Gupta (1987 and Kendall’s test are members of the proposed class. The performance of the proposed class is evaluated in terms of Pitman asymptotic relative efficiency for Block- Basu (1974 model and Woodworth family of distributions. It has been observed that some members of the class perform better than the existing tests in the literature.  Unbiasedness and consistency of the proposed class of tests have been established.

Radiographic positions of femoral ACL, AM and PL centres : accuracy of guidelines based on the lateral quadrant method

NARCIS (Netherlands)

Luites, Joan W.H.; Verdonschot, Nico

2017-01-01

Purpose: Femoral tunnel positioning is an important factor in anatomical ACL reconstructions. To improve accuracy, lateral radiographic support can be used to determine the correct tunnel location, applying the quadrant method. Piefer et al. (Arthroscopy 28:872–881, 2012) combined various outcomes

Virtual blood bank

Directory of Open Access Journals (Sweden)

Kit Fai Wong

2011-01-01

Full Text Available Virtual blood bank is the computer-controlled, electronically linked information management system that allows online ordering and real-time, remote delivery of blood for transfusion. It connects the site of testing to the point of care at a remote site in a real-time fashion with networked computers thus maintaining the integrity of immunohematology test results. It has taken the advantages of information and communication technologies to ensure the accuracy of patient, specimen and blood component identification and to enhance personnel traceability and system security. The built-in logics and process constraints in the design of the virtual blood bank can guide the selection of appropriate blood and minimize transfusion risk. The quality of blood inventory is ascertained and monitored, and an audit trail for critical procedures in the transfusion process is provided by the paperless system. Thus, the virtual blood bank can help ensure that the right patient receives the right amount of the right blood component at the right time.

3D super-virtual refraction interferometry

KAUST Repository

Lu, Kai

2014-08-05

Super-virtual refraction interferometry enhances the signal-to-noise ratio of far-offset refractions. However, when applied to 3D cases, traditional 2D SVI suffers because the stationary positions of the source-receiver pairs might be any place along the recording plane, not just along a receiver line. Moreover, the effect of enhancing the SNR can be limited because of the limitations in the number of survey lines, irregular line geometries, and azimuthal range of arrivals. We have developed a 3D SVI method to overcome these problems. By integrating along the source or receiver lines, the cross-correlation or the convolution result of a trace pair with the source or receiver at the stationary position can be calculated without the requirement of knowing the stationary locations. In addition, the amplitudes of the cross-correlation and convolution results are largely strengthened by integration, which is helpful to further enhance the SNR. In this paper, both synthetic and field data examples are presented, demonstrating that the super-virtual refractions generated by our method have accurate traveltimes and much improved SNR.

A Virtual Aluminum Reduction Cell

Science.gov (United States)

Zhang, Hongliang; Zhou, Chenn Q.; Wu, Bing; Li, Jie

2013-11-01

The most important component in the aluminum industry is the aluminum reduction cell; it has received considerable interests and resources to conduct research to improve its productivity and energy efficiency. The current study focused on the integration of numerical simulation data and virtual reality technology to create a scientifically and practically realistic virtual aluminum reduction cell by presenting complex cell structures and physical-chemical phenomena. The multiphysical field simulation models were first built and solved in ANSYS software (ANSYS Inc., Canonsburg, PA, USA). Then, the methodology of combining the simulation results with virtual reality was introduced, and a virtual aluminum reduction cell was created. The demonstration showed that a computer-based world could be created in which people who are not analysis experts can see the detailed cell structure in a context that they can understand easily. With the application of the virtual aluminum reduction cell, even people who are familiar with aluminum reduction cell operations can gain insights that make it possible to understand the root causes of observed problems and plan design changes in much less time.

Limited Abdominal Sonography for Evaluation of Children With Right Lower Quadrant Pain.

Science.gov (United States)

Munden, Martha M; Wai, Shannon; DiStefano, Michael C; Zhang, Wei

2017-01-01

To determine whether a complete abdominal sonographic examination is necessary in the evaluation of children with right lower quadrant pain that is suspicious for appendicitis in the emergency department and whether performing a limited, more-focused study would miss clinically important disease. With Institutional Review Board approval, a retrospective study was performed of 704 patients, from ages 5-19 years, presenting to the emergency department with right lower quadrant pain that was suspicious for appendicitis who underwent a complete abdominal sonographic examination. Data were extracted from the complete abdominal sonographic examination to see whether abnormalities were noted in the pancreas, spleen, and left kidney. Patients' medical charts were reviewed to see whether any positive findings in these organs were clinically important. Of the 65 studies with a finding that would have been missed with a limited study, only 6 were found to be clinically important. Of those, 5 were managed medically and 1 surgically. The chance of missing a potentially important finding using a limited study with our group of patients was 65 of 704 patients (9.2%), with a 95% confidence interval of 7.2% to 11.7%. The chance of missing an abnormality that was clinically important was 6 of 704 patients (0.85%), with a 95% confidence interval of 0.35% to 1.94%. In children older than 5 years with abdominal pain that is suspicious for appendicitis, performing only a limited abdominal sonographic examination that excludes the pancreas, left kidney, and spleen will yield a miss rate for clinically important disease that is acceptably low to justify the savings of examination time. © 2016 by the American Institute of Ultrasound in Medicine.

73-year-old woman with abdominal pain in the right lower quadrant

International Nuclear Information System (INIS)

Bond, J.R.

1987-01-01

A 73-year-old woman presented with a six-day history of abdominal pain that had started in the epigastrium, but recently had become more intense in the right lower quadrant. Peptic ulcer had been diagnosed three years prior to presentation and had been managed medically. On physical examination, epigastric tenderness as well as guarding and rebound tenderness in the right lower quandrant were present. Mild leukocytosis was reported. Computed tomography demonstrated a 5-cm retrocecal mass with low attenuation (fluid content) surrounded by an irregularly thickened uncalcified wall. Multiple areas of tissue debris were seen extending into the mass, but no true separation was present

Temperature Insensitive Current-Mode Four Quadrant Multiplier Using Single CFCTA

Directory of Open Access Journals (Sweden)

Tuntrakool Sunti

2017-01-01

Full Text Available A four quadrant multiplier of two current input signals using active building block, namely current follower cascaded transconductance amplifier (CFCTA is presented in this paper. The proposed multiplier consists of only single CFCTA without the use of any passive element. The presented circuit has low impedance at current input node and high impedance at current output node which is convenient for cascading in current mode circuit without the need of current buffer circuits. The output current can multiply two input currents with temperature insensitivity. Moreover, the magnitude of output current can be controlled electronically via DC bias current. With only single active building block, the presented multiplier is suitable for integrated circuit implementation for analog signal processing. Simulation results from a PSpice program are presented in order to demonstrate the multiplier proposed here.

Effect of Virtual Reality on Cognition in Stroke Patients

OpenAIRE

Kim, Bo Ryun; Chun, Min Ho; Kim, Lee Suk; Park, Ji Young

2011-01-01

Objective To investigate the effect of virtual reality on the recovery of cognitive impairment in stroke patients. Method Twenty-eight patients (11 males and 17 females, mean age 64.2) with cognitive impairment following stroke were recruited for this study. All patients were randomly assigned to one of two groups, the virtual reality (VR) group (n=15) or the control group (n=13). The VR group received both virtual reality training and computer-based cognitive rehabilitation, whereas the cont...

Delay-based virtual congestion control in multi-tenant datacenters

Science.gov (United States)

Liu, Yuxin; Zhu, Danhong; Zhang, Dong

2018-03-01

With the evolution of cloud computing and virtualization, the congestion control of virtual datacenters has become the basic issue for multi-tenant datacenters transmission. Regarding to the friendly conflict of heterogeneous congestion control among multi-tenant, this paper proposes a delay-based virtual congestion control, which translates the multi-tenant heterogeneous congestion control into delay-based feedback uniformly by setting the hypervisor translation layer, modifying three-way handshake of explicit feedback and packet loss feedback and throttling receive window. The simulation results show that the delay-based virtual congestion control can effectively solve the unfairness of heterogeneous feedback congestion control algorithms.

How does the entrepreneurial orientation of scientists affect their scientific performance? Evidence from the Quadrant Model

OpenAIRE

Naohiro Shichijo; Silvia Rita Sedita; Yasunori Baba

2013-01-01

Using Stokes's (1997) "quadrant model of scientific research", this paper deals with how the entrepreneurial orientation of scientists affects their scientific performance by considering its impact on scientific production (number of publications), scientific prestige (number of forward citations), and breadth of research activities (interdisciplinarity). The results of a quantitative analysis applied to a sample of 1,957 scientific papers published by 66 scientists active in advanced materia...

Can virtual science foster real skills? A study of inquiry skills in a virtual world

Science.gov (United States)

Dodds, Heather E.

Online education has grown into a part of the educational market answering the demand for learning at the learner's choice of time and place. Inquiry skills such as observing, questioning, collecting data, and devising fair experiments are an essential element of 21st-century online science coursework. Virtual immersive worlds such as Second Life are being used as new frontiers in science education. There have been few studies looking specifically at science education in virtual worlds that foster inquiry skills. This quantitative quasi-experimental nonrandomized control group pretest and posttest study explored what affect a virtual world experience had on inquiry skills as measured by the TIPS (Test of Integrated Process Skills) and TIPS II (Integrated Process Skills Test II) instruments. Participants between the ages of 18 and 65 were recruited from educator mailing lists and Second Life discussion boards and then sorted into the experimental group, which received instructions to utilize several displays in Mendelian genetics at the Genome Island location within Second Life, or the control group, which received text-based PDF documents of the same genetics course content. All participants, in the form of avatars, were experienced Second Life residents to reduce any novelty effect. This study found a greater increase in inquiry skills in the experimental group interacting using a virtual world to learn science content (0.90 points) than a control group that is presented only with online text-based content (0.87 points). Using a mixed between-within ANOVA (analysis of variance), with an alpha level of 0.05, there was no significant interaction between the control or experimental groups and inquiry skills, F (1, 58) = .783, p = .380, partial eta squared = .013, at the specified .05 alpha level suggesting no significant difference as a result of the virtual world exercise. However, there is not enough evidence to state that there was no effect because there was a

LHCb experience with running jobs in virtual machines

CERN Document Server

McNab, A; Luzzi, C

2015-01-01

The LHCb experiment has been running production jobs in virtual machines since 2013 as part of its DIRAC-based infrastructure. We describe the architecture of these virtual machines and the steps taken to replicate the WLCG worker node environment expected by user and production jobs. This relies on the uCernVM system for providing root images for virtual machines. We use the CernVM-FS distributed filesystem to supply the root partition files, the LHCb software stack, and the bootstrapping scripts necessary to configure the virtual machines for us. Using this approach, we have been able to minimise the amount of contextualisation which must be provided by the virtual machine managers. We explain the process by which the virtual machine is able to receive payload jobs submitted to DIRAC by users and production managers, and how this differs from payloads executed within conventional DIRAC pilot jobs on batch queue based sites. We describe our operational experiences in running production on VM based sites mana...

3D super-virtual refraction interferometry

KAUST Repository

Lu, Kai; AlTheyab, Abdullah; Schuster, Gerard T.

2014-01-01

Super-virtual refraction interferometry enhances the signal-to-noise ratio of far-offset refractions. However, when applied to 3D cases, traditional 2D SVI suffers because the stationary positions of the source-receiver pairs might be any place

Computed Tomography and Ultrasound of Omental Infarction in Children: Differential Diagnoses of Right Lower Quadrant Pain

Energy Technology Data Exchange (ETDEWEB)

Lim, So Yeoun; Hong, Hyun Sook; Lee, Hae Kyung; Lee, Min Hee [Dept. of Radiology, Soonchunhyang University College of Medicine, Bucheon Hospital, Bucheon (Korea, Republic of); Kim, Young Tong [Dept. of Radiology, Soonchunhyang University College of Medicine, Cheonan Hospital, Cheonan (Korea, Republic of)

2013-03-15

Omental infarction in children occurs rarely and is often confused with other diseases that cause right lower quadrant (RLQ) pain. This study evaluates ultrasonography (US) and computed tomography (CT) findings of omental infarction in children with abdominal pain. The CT and US findings and clinical presentations of nine children diagnosed with omental infarction between 2005 and 2012 were retrospectively reviewed. Distributions of abdominal pain in the patients included RLQ (n = 6), right upper quadrant (RUQ, n = 1), periumbilical (n = 1), and the epigastric (n = 1) region. All patients underwent abdominal CT, and three underwent abdominal US. On CT scan, a typical triangular, heterogeneous fatty mass was seen between the abdominal wall and ascending colon (n = 6) or hepatic flexure (n = 1). A fatty mass with an enhanced rim that mimicked acute appendagitis was present in two patients. The other two patients had diffuse fat infiltration without mass. On US, a heterogeneously hyperechoic omental mass was seen in the RLQ (n = 2) or RUQ (n = 1). Three patients underwent appendectomy and partial omentectomy, and pathology confirmed omental infarction. Knowledge of the typical imaging features of omental infarction and application for diagnosis are important for its differentiation from other conditions that also present with RLQ pain and can avoid unnecessary surgery.

Hierarchical virtual screening approaches in small molecule drug discovery.

Science.gov (United States)

Kumar, Ashutosh; Zhang, Kam Y J

2015-01-01

Virtual screening has played a significant role in the discovery of small molecule inhibitors of therapeutic targets in last two decades. Various ligand and structure-based virtual screening approaches are employed to identify small molecule ligands for proteins of interest. These approaches are often combined in either hierarchical or parallel manner to take advantage of the strength and avoid the limitations associated with individual methods. Hierarchical combination of ligand and structure-based virtual screening approaches has received noteworthy success in numerous drug discovery campaigns. In hierarchical virtual screening, several filters using ligand and structure-based approaches are sequentially applied to reduce a large screening library to a number small enough for experimental testing. In this review, we focus on different hierarchical virtual screening strategies and their application in the discovery of small molecule modulators of important drug targets. Several virtual screening studies are discussed to demonstrate the successful application of hierarchical virtual screening in small molecule drug discovery. Copyright © 2014 Elsevier Inc. All rights reserved.

Super-virtual refraction interferometry: Theory

KAUST Repository

Bharadwaj, Pawan

2011-01-01

Inverting for the subsurface velocity distribution by refraction traveltime tomography is a well-accepted imaging method by both the exploration and earthquake seismology communities. A significant drawback, however, is that the recorded traces become noisier with increasing offset from the source position, and so prevents accurate picking of traveltimes in far-offset traces. To enhance the signal-to-noise ratio of the far-offset traces, we present the theory of super-virtual refraction interferometry where the signal-to-noise ratio (SNR) of far-offset head-wave arrivals can be theoretically increased by a factor proportional to N; here, N is the number of receiver and source positions associated with the recording and generation of the head-wave arrival. There are two steps to this methodology: correlation and summation of the data to generate traces with virtual head-wave arrivals, followed by the convolution of the data with the virtual traces to create traces with super-virtual head-wave arrivals. This method is valid for any medium that generates head-wave arrivals. There are at least three significant benefits to this methodology: 1). enhanced SNR of far-offset traces so the first-arrival traveltimes of the noisy far-offset traces can be more reliably picked to extend the useful aperture of data, 2). the SNR of head waves in a trace that arrive after the first arrival can be enhanced for accurate traveltime picking and subsequent inversion by traveltime tomography, and 3). common receiver-pair gathers can be analyzed to detect the presence of diving waves in the first arrivals, which can be used to assess the nature of the refracting boundary. © 2011 Society of Exploration Geophysicists.

Use of virtual reality to estimate radiation dose rates in nuclear plants

International Nuclear Information System (INIS)

Augusto, Silas C.; Mol, Antonio C.A.; Jorge, Carlos A.F.; Couto, Pedro M.

2007-01-01

Operators in nuclear plants receive radiation doses during several different operation procedures. A training program capable of simulating these operation scenarios will be useful in several ways, helping the planning of operational procedures so as to reduce the doses received by workers, and to minimize operations' times. It can provide safe virtual operation training, visualization of radiation dose rates, and estimation of doses received by workers. Thus, a virtual reality application, a free game engine, has been adapted to achieve the goals of this project. Simulation results for Argonauta research reactor of Instituto de Engenharia Nuclear are shown in this paper. A database of dose rate measurements, previously performed by the radiological protection service, has been used to display the dose rate distribution in the region of interest. The application enables the user to walk in the virtual scenario, displaying at all times the dose accumulated by the avatar. (author)

Four quadrant control circuit for a brushless three-phase dc motor

Science.gov (United States)

Nola, Frank J. (Inventor)

1987-01-01

A control circuit is provided for a brushless three-phase dc motor which affords four quadrant control from a single command. The control circuit probes acceleration of the motor in both clockwise and counterclockwise directions and braking and generation in both clockwise and counterclockwise directions. In addition to turning on individual transistors of the transistor pairs connected to the phase windings of the motor for 120 deg periods while the other transistor of that pair is off, the control circuit also provides, in a future mode of operation, turning the two transistors of each pair on and off alternately at a phase modulation frequency during such a 120 deg period. A feedback signal is derived which is proportional to the motor current and which has a polarity consistent with the command signal, such that negative feedback results.

Virtually teaching virtual leadership

DEFF Research Database (Denmark)

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

2017-01-01

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....

Teaching Basic Field Skills Using Screen-Based Virtual Reality Landscapes

Science.gov (United States)

Houghton, J.; Robinson, A.; Gordon, C.; Lloyd, G. E. E.; Morgan, D. J.

2016-12-01

We are using screen-based virtual reality landscapes, created using the Unity 3D game engine, to augment the training geoscience students receive in preparing for fieldwork. Students explore these landscapes as they would real ones, interacting with virtual outcrops to collect data, determine location, and map the geology. Skills for conducting field geological surveys - collecting, plotting and interpreting data; time management and decision making - are introduced interactively and intuitively. As with real landscapes, the virtual landscapes are open-ended terrains with embedded data. This means the game does not structure student interaction with the information as it is through experience the student learns the best methods to work successfully and efficiently. These virtual landscapes are not replacements for geological fieldwork rather virtual spaces between classroom and field in which to train and reinforcement essential skills. Importantly, these virtual landscapes offer accessible parallel provision for students unable to visit, or fully partake in visiting, the field. The project has received positive feedback from both staff and students. Results show students find it easier to focus on learning these basic field skills in a classroom, rather than field setting, and make the same mistakes as when learning in the field, validating the realistic nature of the virtual experience and providing opportunity to learn from these mistakes. The approach also saves time, and therefore resources, in the field as basic skills are already embedded. 70% of students report increased confidence with how to map boundaries and 80% have found the virtual training a useful experience. We are also developing landscapes based on real places with 3D photogrammetric outcrops, and a virtual urban landscape in which Engineering Geology students can conduct a site investigation. This project is a collaboration between the University of Leeds and Leeds College of Art, UK, and all

Historical tank content estimate for the northwest quadrant of the Hanford 200 west area

International Nuclear Information System (INIS)

Brevick, C.H.; Stroup, J.L.; Funk, J.W.

1997-01-01

The Historical Tank Content Estimate for the Quadrant provides historical information on a tank-by-tank basis of the radioactive mixed wastes stored in the underground single-shell tanks for the Hanford 200 West Area. This report summarized historical information such as waste history, level history, temperature history, riser configuration, tank integrity, and inventory estimates on a tank-by-tank basis. Tank farm aerial photographs and interior tank montages are also provided for each tank. A description of the development of data for the document of the inventory estimates provided by Los Alamos National Laboratory are also given in this report

Super-Virtual Refraction Interferometric Redatuming: Enhancing the Refracted Energy

KAUST Repository

Aldawood, Ali

2012-02-26

onshore seismic data processing. Refraction tomography is becoming a common way to estimate an accurate near surface velocity model. One of the problems with refraction tomography is the low signal to noise ration in far offset data. To improve, we propose using super-virtual refraction interferometry to enhance the weak energy at far offsets. We use Interferometric Green\\'s functions to redatum sources by cross-correlating two traces recorded at receiver stations, A and B, from a source at location W. The result is a redatumed trace with a virtual source at A and a receiver at B, which can also be obtained by correlating two traces recorded at A and B from different shots. Stacking them would enhance the signal-to-noise ratio of this "virtual" trace. We next augment redatuming with convolution and stacking. The trace recorded at B from a virtual source at A is convolved with the original trace recorded at A from a source at W. The result is a "super-virtual" trace at B in the far-offset from a source at W. Stacking N traces gives a vN-improvement. We applied our method to noisy synthetic and field data recorded over a complex near-surface and we could pick more traces at far offsets. It was possible to accommodate more picks resulting in a better subsurface coverage

Super-Virtual Refraction Interferometric Redatuming: Enhancing the Refracted Energy

KAUST Repository

Aldawood, Ali; Alshuhail, Abdulrahman Abdullatif Abdulrahman; Hanafy, Sherif

2012-01-01

onshore seismic data processing. Refraction tomography is becoming a common way to estimate an accurate near surface velocity model. One of the problems with refraction tomography is the low signal to noise ration in far offset data. To improve, we propose using super-virtual refraction interferometry to enhance the weak energy at far offsets. We use Interferometric Green's functions to redatum sources by cross-correlating two traces recorded at receiver stations, A and B, from a source at location W. The result is a redatumed trace with a virtual source at A and a receiver at B, which can also be obtained by correlating two traces recorded at A and B from different shots. Stacking them would enhance the signal-to-noise ratio of this "virtual" trace. We next augment redatuming with convolution and stacking. The trace recorded at B from a virtual source at A is convolved with the original trace recorded at A from a source at W. The result is a "super-virtual" trace at B in the far-offset from a source at W. Stacking N traces gives a vN-improvement. We applied our method to noisy synthetic and field data recorded over a complex near-surface and we could pick more traces at far offsets. It was possible to accommodate more picks resulting in a better subsurface coverage

Children Presenting at the Emergency Department With Right Lower Quadrant Pain

Directory of Open Access Journals (Sweden)

Chien-Heng Lin

2009-01-01

Full Text Available Right lower quadrant (RLQ pain is a common complaint in children presenting at emergency departments. This study analyzed the etiologies of RLQ pain, and compared the clinical presentations, laboratory test results and imaging findings in patients with appendicitis with those in other groups of patients. We also investigated if active observation resulted in delayed diagnosis, to the detriment of patients. Medical records for the period January 2006 to July 2006 were reviewed for children (age < 18 years who presented to the emergency department of one medical center, complaining of RLQ pain. Out of a total of 100 patients (age range: 2–17 years; mean: 11 years, 46 patients presented with only one symptom of RLQ pain, while 32 patients had ≥ 2 associated signs or symptoms, including fever, nausea/vomiting, diarrhea, or rebound tenderness. Imaging studies, including abdominal sonography and/or computed tomography, were performed in 73 patients; 44 underwent surgery for presumed appendicitis and one received surgery for a right paraduodenal hernia. Eleven patients underwent surgery because of peritoneal signs, and eight because of persistent or aggravated RLQ pain. Postoperative pathologic examinations revealed 53 cases of appendicitis, six normal appendices, and other morbidities (1 perforated peptic ulcer, 1 pelvic inflammatory disease, 1 ovarian cyst, 1 diverticulitis, and 1 right paraduodenal hernia. Thirty-three patients were discharged after several hours of observation (range: 0.5–18 hours; mean: 4 hours, and three patients were admitted for further observations. All were discharged without operation. There were significant differences in the incidences of fever (p = 0.004 and rebound tenderness (p = 0.019, and in white cell counts (p < 0.001, neutrophil percentages (p < 0.001, and C-reactive protein levels (p < 0.001 between patients with appendicitis and patients with other causes of RLQ pain. Clinical signs and symptoms, laboratory

Controlling Within-Field Sheep Movement Using Virtual Fencing.

Science.gov (United States)

Marini, Danila; Llewellyn, Rick; Belson, Sue; Lee, Caroline

2018-02-26

Virtual fencing has the potential to greatly improve livestock movement, grazing efficiency, and land management by farmers; however, relatively little work has been done to test the potential of virtual fencing with sheep. Commercial dog training equipment, comprising of a collar and GPS hand-held unit were used to implement a virtual fence in a commercial setting. Six, 5-6 year-old Merino wethers, which were naïve to virtual fencing were GPS tracked for their use of a paddock (80 × 20 m) throughout the experiment. The virtual fence was effective at preventing a small group of sheep from entering the exclusion zone. The probability of a sheep receiving an electrical stimulus following an audio cue was low (19%), and declined over the testing period. It took an average of eight interactions with the fence for an association to be made between the audio and stimulus cue, with all of the animals responding to the audio alone by the third day. Following the removal of the virtual fence, sheep were willing to cross the previous location of the virtual fence after 30 min of being in the paddock. This is an important aspect in the implementation of virtual fencing as a grazing management tool and further enforces that the sheep in this study were able to associate the audio with the virtual fence and not the physical location itself.

Design of a High Linearity Four-Quadrant Analog Multiplier in Wideband Frequency Range

Directory of Open Access Journals (Sweden)

Abdul kareem Mokif Obais

2017-05-01

Full Text Available In this paper, a voltage mode four quadrant analog multiplier in the wideband frequency rangeis designed using a wideband operational amplifier (OPAMP and squaring circuits. The wideband OPAMP is designed using 10 identical NMOS transistorsand operated with supply voltages of ±12V. Two NMOS transistors and two wideband OPAMP are utilized in the design of the proposed squaring circuit. All the NMOS transistors are based on 0.35µm NMOStechnology. The multiplier has input and output voltage ranges of ±10 V, high range of linearity from -10 V to +10 V, and cutoff frequency of about 5 GHz. The proposed multiplier is designed on PSpice in Orcad 16.6

Integration of the virtual 3D model of a control system with the virtual controller

Science.gov (United States)

Herbuś, K.; Ociepka, P.

2015-11-01

Nowadays the design process includes simulation analysis of different components of a constructed object. It involves the need for integration of different virtual object to simulate the whole investigated technical system. The paper presents the issues related to the integration of a virtual 3D model of a chosen control system of with a virtual controller. The goal of integration is to verify the operation of an adopted object of in accordance with the established control program. The object of the simulation work is the drive system of a tunneling machine for trenchless work. In the first stage of work was created an interactive visualization of functioning of the 3D virtual model of a tunneling machine. For this purpose, the software of the VR (Virtual Reality) class was applied. In the elaborated interactive application were created adequate procedures allowing controlling the drive system of a translatory motion, a rotary motion and the drive system of a manipulator. Additionally was created the procedure of turning on and off the output crushing head, mounted on the last element of the manipulator. In the elaborated interactive application have been established procedures for receiving input data from external software, on the basis of the dynamic data exchange (DDE), which allow controlling actuators of particular control systems of the considered machine. In the next stage of work, the program on a virtual driver, in the ladder diagram (LD) language, was created. The control program was developed on the basis of the adopted work cycle of the tunneling machine. The element integrating the virtual model of the tunneling machine for trenchless work with the virtual controller is the application written in a high level language (Visual Basic). In the developed application was created procedures responsible for collecting data from the running, in a simulation mode, virtual controller and transferring them to the interactive application, in which is verified the

Diagnosis of Appendicitis with Left Lower Quadrant Pain

Directory of Open Access Journals (Sweden)

Sen-Kuang Hou

2005-12-01

Full Text Available Abdominal pain is one of the most common chief complaints of patients presenting to the emergency department and, among the diagnoses of abdominal pain, appendicitis is the most common surgical disorder. Traditionally, the diagnosis of appendicitis is based on well-established clinical criteria combined with physician experience. However, appendicitis presenting with rare and misleading left lower quadrant (LLQ pain may result in an initial false-negative diagnosis by the physician and even result in failure to order the subsidiary examination of computed tomography (CT or ultrasound, so increasing the risk of perforation/abscess formation and prolonged hospital stay. In this report, we present 2 cases of atypical appendicitis with LLQ pain where the correct diagnosis was not initially considered. One patient had right-sided appendicitis; the inflamed appendix was 12 cm in length and projected into the LLQ. Local peritonitis developed during observation. With the aid of CT, the diagnosis was established in time. The other patient had left-sided appendicitis with situs inversus totalis. Adverse outcomes with appendiceal rupture and abscess formation occurred due to inadvertent physical examinations and inadequate observation. Early clinical suspicion and adequate observation are indicated in patients with uncertain clinical features. However, in patients with unresolved clinical symptoms and/or local peritonitis that develop during observation, imaging studies play a significant role in preoperative diagnosis and determination of proper treatment.

Development of a position sensor based on a four quadrant structured optic fiber bundle

International Nuclear Information System (INIS)

Boukellal, Younes; Ducourtieux, Sebastien

2015-01-01

This article reports on the development of a new kind of 2D displacement sensor based on an optic fiber bundle whose fiber arrangement has been customized to provide an input sensitive surface with four quadrants. The fibers of each quadrant are regrouped to form four output arms. The aim is to reach behavior similar to that of a quad cell photodiode when illuminated by a laser spot. In this paper, we present the motivations for developing such a sensor and its design. Prior to the fabrication of a first prototype, the optic fiber bundle has been modelled and compared to a quad cell photodiode. It has an active surface which is 10 mm in diameter and which comprises 40 000 fibers of 50 µm core diameter. For this experimental test, a specific electronic conditioning circuit has been developed to process the signals. From both modelled and experimental results, fiber optic bundle and quad cell photodiode behavior has proved to be very similar, provided that the number of fibers is sufficient to achieve a statistical effect on the detected displacement, i.e. the laser spot diameter is rightly chosen as a function of the fiber diameter. For the use of the bundle as position sensor, a laser spot size of 5 mm has been fixed to achieve a good compromise between sensitivity and displacement range. With this spot size, sensitivity and displacement range have been experimentally evaluated to 2 mV µm −1 and 3.8 mm respectively with a corresponding displacement resolution of 5 nm in the best case. (paper)

A vector modulated three-phase four-quadrant rectifier - Application to a dc motor drive

Energy Technology Data Exchange (ETDEWEB)

Jussila, Matti; Salo, Mika; Kaehkoenen, Lauri; Tuusa, Heikki

2004-07-01

This paper introduces a theory for a space vector modulation of a three-phase four-quadrant PWM rectifier (FQR). The presented vector modulation method is simple to realize with a microcontroller and it replaces the conventional modulation methods based on the analog technology. The FQR may be used to supply directly a dc load, e.g. a dc machine. The vector modulated FQR is tested in simulations supplying a 4.5 kW dc motor. The simulations show the benefits of the vector modulated FQR against thyristor converters: the supply currents are sinusoidal and the displacement power factor of the supply can be controlled. Furthermore the load current is smooth. (author)

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.

LHCb experience with running jobs in virtual machines

Science.gov (United States)

McNab, A.; Stagni, F.; Luzzi, C.

2015-12-01

The LHCb experiment has been running production jobs in virtual machines since 2013 as part of its DIRAC-based infrastructure. We describe the architecture of these virtual machines and the steps taken to replicate the WLCG worker node environment expected by user and production jobs. This relies on the uCernVM system for providing root images for virtual machines. We use the CernVM-FS distributed filesystem to supply the root partition files, the LHCb software stack, and the bootstrapping scripts necessary to configure the virtual machines for us. Using this approach, we have been able to minimise the amount of contextualisation which must be provided by the virtual machine managers. We explain the process by which the virtual machine is able to receive payload jobs submitted to DIRAC by users and production managers, and how this differs from payloads executed within conventional DIRAC pilot jobs on batch queue based sites. We describe our operational experiences in running production on VM based sites managed using Vcycle/OpenStack, Vac, and HTCondor Vacuum. Finally we show how our use of these resources is monitored using Ganglia and DIRAC.

Virtual reality for the treatment of autism.

Science.gov (United States)

Strickland, D

1997-01-01

Autism is a mental disorder which has received attention in several unrelated studies using virtual reality. One of the first attempts was to diagnose children with special needs at Tokyo University using a sandbox playing technique. Although operating the computer controls proved to be too difficult for the individuals with autism in the Tokyo study, research at the University of Nottingham, UK, is successful in using VR as a learning aid for children with a variety of disorders including autism. Both centers used flat screen computer systems with virtual scenes. Another study which concentrated on using VR as a learning aid with an immersive headset system is described in detail in this chapter. Perhaps because of the seriousness of the disorder and the lack of effective treatments, autism has received more study than attention deficit disorders, although both would appear to benefit from many of the same technology features.

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...

Assessment of radiation awareness training in immersive virtual environments

Science.gov (United States)

Whisker, Vaughn E., III

The prospect of new nuclear power plant orders in the near future and the graying of the current workforce create a need to train new personnel faster and better. Immersive virtual reality (VR) may offer a solution to the training challenge. VR technology presented in a CAVE Automatic Virtual Environment (CAVE) provides a high-fidelity, one-to-one scale environment where areas of the power plant can be recreated and virtual radiation environments can be simulated, making it possible to safely expose workers to virtual radiation in the context of the actual work environment. The use of virtual reality for training is supported by many educational theories; constructivism and discovery learning, in particular. Educational theory describes the importance of matching the training to the task. Plant access training and radiation worker training, common forms of training in the nuclear industry, rely on computer-based training methods in most cases, which effectively transfer declarative knowledge, but are poor at transferring skills. If an activity were to be added, the training would provide personnel with the opportunity to develop skills and apply their knowledge so they could be more effective when working in the radiation environment. An experiment was developed to test immersive virtual reality's suitability for training radiation awareness. Using a mixed methodology of quantitative and qualitative measures, the subjects' performances before and after training were assessed. First, subjects completed a pre-test to measure their knowledge prior to completing any training. Next they completed unsupervised computer-based training, which consisted of a PowerPoint presentation and a PDF document. After completing a brief orientation activity in the virtual environment, one group of participants received supplemental radiation awareness training in a simulated radiation environment presented in the CAVE, while a second group, the control group, moved directly to the

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

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.

Economic aspects of virtual water trade

Science.gov (United States)

Oki, Taikan; Yano, Shinjiro; Hanasaki, Naota

2017-04-01

Although water is rarely traded over long distances by itself, the total weight of the water consumed to produce traded commodities exceeds the weight of any other commodity traded in the world. This concept is known as virtual water trade. Although space-/time-/commodity-based quantification has been conducted extensively, the underlying causes of this peculiar feature have thus far received little exploration. Here, we use estimates of water consumption from a global hydrological model and statistical data related to food trade to elucidate three facts that explain the fundamental nature of virtual water trade with respect to alleviating water scarcity. First, we quantitatively illustrate the unique position of water among commodities based on its unit price and quantity of sales. Water has an extremely low unit price, and a tremendous volume of water is consumed per person each day. Second, we show that rich but water-scarce countries tend to reduce local water consumption by importing virtual water. Third, we demonstrate that nations characterized by net virtual water exports have higher water resources and income per capita and that no countries fall below a certain threshold with respect to both GDP and water resources. These points suggest that the virtual water trade is explained by economic characteristics of water and that sustainable development depends on promoting the co-development of poverty alleviation and water resource development.

Imaging the Moho beneath Sedimentary Basins: A Comparative Study of Virtual Deep Seismic Sounding (VDSS) and P Wave Receiver Functions (PRF)

Science.gov (United States)

Liu, T.; Klemperer, S. L.; Yu, C.; Ning, J.

2017-12-01

In the past decades, P wave receiver functions (PRF) have been routinely used to image the Moho, although it is well known that PRFs are susceptible to contamination from sedimentary multiples. Recently, Virtual Deep Seismic Sounding (VDSS) emerged as a novel method to image the Moho. However, despite successful applications of VDSS on multiple datasets from different areas, how sedimentary basins affect the waveforms of post-critical SsPmp, the Moho reflection phase used in VDSS, is not widely understood. Here, motivated by a dataset collected in the Ordos plateau, which shows distinct effects of sedimentary basins on SsPmp and Pms waveforms, we use synthetic seismograms to study the effects of sedimentary basins on SsPmp and Pms, the phases used in VDSS and PRF respectively. The results show that when the sedimentary thickness is on the same order of magnitude as the dominant wavelength of the incident S wave, SsPmp amplitude decreases significantly with S velocity of the sedimentary layer, whereas increasing sedimentary thickness has little effect in SsPmp amplitude. Our explanation is that the low S velocity layer at the virtual source reduces the incident angle of S wave at the free surface, thus decreases the S-to-P reflection coefficient at the virtual source. In addition, transmission loss associated with the bottom of sedimentary basins also contributes to reducing SsPmp amplitude. This explains not only our observations from the Ordos plateau, but also observations from other areas where post-critical SsPmp is expected to be observable, but instead is too weak to be identified. As for Pms, we observe that increasing sedimentary thickness and decreasing sedimentary velocities both can cause interference between sedimentary multiples and Pms, rendering the Moho depths inferred from Pms arrival times unreliable. The reason is that although Pms amplitude does not vary with sedimentary thickness or velocities, as sedimentary velocities decrease and thickness

Desktop Virtualization in Action: Simplicity Is Power

Science.gov (United States)

Fennell, Dustin

2010-01-01

Discover how your institution can better manage and increase access to instructional applications and desktops while providing a blended learning environment. Receive practical insight into how academic computing virtualization can be leveraged to enhance education at your institution while lowering Total Cost of Ownership (TCO) and reducing the…

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

Synthetic aperture ultrasound Fourier beamformation using virtual sources

DEFF Research Database (Denmark)

Moghimirad, Elahe; Villagómez Hoyos, Carlos Armando; Mahloojifar, Ali

2016-01-01

An efficient Fourier beamformation algorithm is presented for multistatic synthetic aperture ultrasound imaging using virtual sources (FBV). The concept is based on the frequency domain wavenumber algorithm from radar and sonar and is extended to a multi-element transmit/receive configuration using...

Reality in Virtual Learning

DEFF Research Database (Denmark)

Lindberg, Frank; Pettersson, Michael

professors most often decide what and when one could learn by providing the context and substance. In this perspective, the student has a role which is close to the one of a passive receiver, and s/he is mainly preoccupied with the problem of generating substance in memory most efficiently. Today, technology......-time educational logic. There are fewer attempts to use ICT according to a different pedagogical perspective than the old professor authoritarian model. The purpose of this paper is to illuminate some challenges virtual students experience when facing a new ICT-based learning situation. We will try to explore...... and develop understandings of what it might mean to be a student when learning occurs within a virtual problem based learning landscape. When students are used to the traditional classroom, challenges appear in the twilight zone between two pedagogical practices. How do the students cope with challenges...

Virtual Class Support at the Virtual Machine Level

DEFF Research Database (Denmark)

Nielsen, Anders Bach; Ernst, Erik

2009-01-01

This paper describes how virtual classes can be supported in a virtual machine.  Main-stream virtual machines such as the Java Virtual Machine and the .NET platform dominate the world today, and many languages are being executed on these virtual machines even though their embodied design choices...... conflict with the design choices of the virtual machine.  For instance, there is a non-trivial mismatch between the main-stream virtual machines mentioned above and dynamically typed languages.  One language concept that creates an even greater mismatch is virtual classes, in particular because fully...... general support for virtual classes requires generation of new classes at run-time by mixin composition.  Languages like CaesarJ and ObjectTeams can express virtual classes restricted to the subset that does not require run-time generation of classes, because of the restrictions imposed by the Java...

A Quadrant Analysis on the Effectiveness of Planning and Control in Urban Housing Development in Selangor

Directory of Open Access Journals (Sweden)

Hamizah Yakob

2016-01-01

Full Text Available The current planning mechanisms which are development plan and planning control were recognised as important tools in housing planning process. However, the weaknesses involved in the preparation of development plans and its implementation through development control may impose constraints on housing development. The objective of this paper is to evaluate whether the housing planning and control activities practiced require improvement in terms of the level of effectiveness of its implementation by the LPAs and PCs in Selangor using Quadrant Analysis. It was found that three activities; location, compliance and difficulties need high attention to achieve effective housing planning control.

Virtual planning of complex head and neck reconstruction results in satisfactory match between real outcomes and virtual models.

Science.gov (United States)

Hanken, Henning; Schablowsky, Clemens; Smeets, Ralf; Heiland, Max; Sehner, Susanne; Riecke, Björn; Nourwali, Ibrahim; Vorwig, Oliver; Gröbe, Alexander; Al-Dam, Ahmed

2015-04-01

The reconstruction of large facial bony defects using microvascular transplants requires extensive surgery to achieve full rehabilitation of form and function. The purpose of this study is to measure the agreement between virtual plans and the actual results of maxillofacial reconstruction. This retrospective cohort study included 30 subjects receiving maxillofacial reconstruction with a preoperative virtual planning. Parameters including defect size, position, angle and volume of the transplanted segments were compared between the virtual plan and the real outcome using paired t test. A total of 63 bone segments were transplanted. The mean differences between the virtual planning and the postoperative situation were for the defect sizes 1.17 mm (95 % confidence interval (CI) (-.21 to 2.56 mm); p = 0.094), for the resection planes 1.69 mm (95 % CI (1.26-2.11); p = 0.033) and 10.16° (95 % CI (8.36°-11.96°); p satisfactory postoperative results are the basis for an optimal functional and aesthetic reconstruction in a single surgical procedure. The technique should be further investigated in larger study populations and should be further improved.

10 μ m-thick four-quadrant transmissive silicon photodiodes for beam position monitor application: electrical characterization and gamma irradiation effects

Science.gov (United States)

Rafí, J. M.; Pellegrini, G.; Quirion, D.; Hidalgo, S.; Godignon, P.; Matilla, O.; Juanhuix, J.; Fontserè, A.; Molas, B.; Pothin, D.; Fajardo, P.

2017-01-01

Silicon photodiodes are very useful devices as X-ray beam monitors in synchrotron radiation beamlines. Owing to Si absorption, devices thinner than 10 μ m are needed to achieve transmission over 90% for energies above 10 keV . In this work, new segmented four-quadrant diodes for beam alignment purposes are fabricated on both ultrathin (10 μ m-thick) and bulk silicon substrates. Four-quadrant diodes implementing different design parameters as well as auxiliary test structures (single diodes and MOS capacitors) are studied. An extensive electrical characterization, including current-voltage (I-V) and capacitance-voltage (C-V) techniques, is carried out on non-irradiated and gamma-irradiated devices up to 100 Mrad doses. Special attention is devoted to the study of radiation-induced charge build-up in diode interquadrant isolation dielectric, as well as its impact on device interquadrant resistance. Finally, the devices have been characterized with an 8 keV laboratory X-ray source at 108 ph/s and in BL13-XALOC ALBA Synchroton beamline with 1011 ph/s and energies from 6 to 16 keV . Sensitivity, spatial resolution and uniformity of the devices have been evaluated.

Virtual Hand Feedback Reduces Reaction Time in an Interactive Finger Reaching Task.

Directory of Open Access Journals (Sweden)

Johannes Brand

Full Text Available Computer interaction via visually guided hand or finger movements is a ubiquitous part of daily computer usage in work or gaming. Surprisingly, however, little is known about the performance effects of using virtual limb representations versus simpler cursors. In this study 26 healthy right-handed adults performed cued index finger flexion-extension movements towards an on-screen target while wearing a data glove. They received each of four different types of real-time visual feedback: a simple circular cursor, a point light pattern indicating finger joint positions, a cartoon hand and a fully shaded virtual hand. We found that participants initiated the movements faster when receiving feedback in the form of a hand than when receiving circular cursor or point light feedback. This overall difference was robust for three out of four hand versus circle pairwise comparisons. The faster movement initiation for hand feedback was accompanied by a larger movement amplitude and a larger movement error. We suggest that the observed effect may be related to priming of hand information during action perception and execution affecting motor planning and execution. The results may have applications in the use of body representations in virtual reality applications.

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

Droni e turismo virtuale

Directory of Open Access Journals (Sweden)

Valeria Minucciani

2015-08-01

Full Text Available Virtual tourism has been through at least three generations. The first is a special form of e-commerce, and no doubt it has much changed the way you plan your travel. Second generation of virtual tourism has exploited georeference: the user can know the services offered nearby and, with appropriate apps and augmented reality, receive information about places. An important contribution has been made in this field by social media (see Flickr, as well as Tripadvisor. The third generation of virtual tourism even replaces the travel experience: first proposing visits in virtual worlds, then in the real world. That allows tourism to social classes that are excluded. The goal is to send in the real place an "avatar", that can perform what tourist wants. Some experiments have been recently performed with robots, here a visit by drones is proposed. In particular, indoor visits are difficult because it is necessary to re-create a microgeodetic reference system in a closed and confined environment, to allow remote control and to ensure the protection of the cultural property. It has also to be considered the issue of the size of the drone, its autonomy and shooting video (which must be 360 degrees and high definition. The real experience is irreplaceable, but this form of tourism can find many interesting applications and strengthen real tourism. In conclusion, we believe that not only this performances are now within the reach of our technical capabilities, but  they also represent an effective response to certain social and cultural issues.

Droni e turismo virtuale

Directory of Open Access Journals (Sweden)

Valeria Minucciani

2015-08-01

Full Text Available Virtual tourism has been through at least three generations.The first is a special form of e-commerce, and no doubt it has much changed the way you plan your travel. Second generation of virtual tourism has exploited georeference: the user can know the services offered nearby and, with appropriate apps and augmented reality, receive information about places.An important contribution has been made in this field by social media (see Flickr, as well as Tripadvisor. The third generation of virtual tourism even replaces the travel experience: first proposing visits in virtual worlds, then in the real world. That allows tourism to social classes that are excluded.The goal is to send in the real place an "avatar", that can perform what tourist wants. Some experiments have been recently performed with robots, here a visit by drones is proposed. In particular, indoor visits are difficult because it is necessary to re-create a microgeodetic reference system in a closed and confined environment, to allow remote control and to ensure the protection of the cultural property. It has also to be considered the issue of the size of the drone, its autonomy and shooting video (which must be 360 degrees and high definition.The real experience is irreplaceable, but this form of tourism can find many interesting applications and strengthen real tourism.In conclusion, we believe that not only this performances are now within the reach of our technical capabilities, but  they also represent an effective response to certain social and cultural issues. 

METAL DELM - metal avrelianis contribution to the study of mining coins and anonymous quadrantes

Directory of Open Access Journals (Sweden)

Vojvoda Mirjana D.

2016-01-01

Full Text Available In the course of rescue archaeological investigations at the Viminacium necropolis of Vi{e Grobalja in 1984, one anonymous quadrans of the VIII Apollo group was discovered (cat. 1. It was discovered in trench 63 in the immediate vicinity of a grave with an inhumation (G 343 that, besides two pottery vessels, also yielded as grave offerings one as of Faustina the Elder, minted after her death, in AD 141. Other finds presented here are four specimens of Roman mining coins from the private collection of Petar Fajfri} from [abac (cat. 2-5. All specimens come from the well known site of Duge Njive in the area of the village of Banatsko Polje (Bogati} borough where, by all appearances, are the remains of a vicus or smaller settlement. Five specimens of mining coins from that site have already been published. Both mining coins and anonymous quadrantes represent, in general, rare types of numismatic finds. Nine anonymous quadrantes are known so far from the territory of Serbia (Table 1 and the provenance is known for three specimens from the region of Guberevac-Babe (Kosmaj, housed in the National Museum in Belgrade. All three belong to the Minerva group with an owl facing to the right represented on the reverse. For two more anonymous quadrantes the place of discovery is known: one specimen comes from Singidunum and belongs to the Mercury group and the other that was found at Viminacium and is the subject of this paper is of the Apollo group. There are four more specimens from unknown sites for which it is assumed that they come from the Upper Moesia territory. Two of them are from the Vajfert collection and two from the Kovačević collection in the National Museum in Belgrade, There has, however, been a somewhat greater number (38 of Roman mining coins discovered in Serbia (Table 1. We know the finding locations of 25 of them: from the Kosmaj area (Babe, Guberevac and Stojnik, the Ibar valley (from the vicinity of Trepča and So~anica, Ritopek

Imaging the child with right lower quadrant pain and suspected appendicitis: current concepts

Energy Technology Data Exchange (ETDEWEB)

Sivit, Carlos J. [Departments of Radiology and Pediatrics, Rainbow Babies and Childrens Hospital of the University Hospitals of Cleveland and Case Western Reserve School of Medicine, Euclid Avenue, 11100, 44106-5056, Cleveland, OH (United States)

2004-06-01

Acute appendicitis is the most common condition presenting with right lower quadrant pain requiring acute surgical intervention in childhood. The clinical diagnosis of acute appendicitis is often not straightforward and can be challenging. Approximately one-third of children with the condition have atypical clinical findings and are initially managed non-operatively. Complications usually result from perforation and include abscess formation, peritonitis, sepsis, bowel obstruction and death. Cross-sectional imaging with sonography and computed tomography (CT) have proven useful for the evaluation of suspected acute appendicitis in children. The principal advantages of sonography are its lower cost, lack of ionizing radiation, and ability to precisely delineate gynecologic disease. The principal advantages of CT are its operator independency with resultant higher diagnostic accuracy, enhanced delineation of disease extent in perforated appendicitis, and improved patient outcomes including decreased negative laparotomy and perforation rates. (orig.)

Cognitive correlates of spatial navigation: Associations between executive functioning and the virtual Morris Water Task.

Science.gov (United States)

Korthauer, L E; Nowak, N T; Frahmand, M; Driscoll, I

2017-01-15

Although effective spatial navigation requires memory for objects and locations, navigating a novel environment may also require considerable executive resources. The present study investigated associations between performance on the virtual Morris Water Task (vMWT), an analog version of a nonhuman spatial navigation task, and neuropsychological tests of executive functioning and spatial performance in 75 healthy young adults. More effective vMWT performance (e.g., lower latency and distance to reach hidden platform, greater distance in goal quadrant on a probe trial, fewer path intersections) was associated with better verbal fluency, set switching, response inhibition, and ability to mentally rotate objects. Findings also support a male advantage in spatial navigation, with sex moderating several associations between vMWT performance and executive abilities. Overall, we report a robust relationship between executive functioning and navigational skill, with some evidence that men and women may differentially recruit cognitive abilities when navigating a novel environment. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparison of first quadrant yield loci for Ti--6Al--4V with those predicted by Knoop hardness measurements

International Nuclear Information System (INIS)

Amateau, M.F.; Hanna, W.D.

1975-01-01

Knoop hardness impressions were used to construct biaxial yield loci in Ti--6A l--4V for a variety of textures. These results were compared with partial yield loci in the first quadrant, determined from flow stress measurements at three stress ratios. In each case, the Knoop hardness technique was not sufficiently sensitive to predict the shape of the yield locus, the largest discrepancy occurring for the most anisotropic sample. (U.S.)

Virtual Library: An essential component of virtual education

Directory of Open Access Journals (Sweden)

M zarghani

2015-06-01

Full Text Available Abstract Introduction: Library is one of the essential elements of universities which provide some important educational needs of students. Virtual education can not be exempted and virtual libraries are important support for virtual training programs. The purpose of this study is to evaluate the viewpoint of administrators and students in virtual education centers about the virtual library, its role and resources. Methods: This study was a descriptive survey. The research instrument was a researcher made questionnaire that its validity and reliability was confirmed. The study population consisted of 19 virtual training centers in Tehran city. Out of 19 centers, simple randomized sampling was done in five Centers. The sample size was 360 students. Data collection was conducted online and descriptive statistics using SPSS 18 and Excel software were used. Results: The results showed that viewpoints of administrators and students about the mission and services of virtual libraries in some cases were similar and in some cases were different. One of the administrators’ reasons for setting up a virtual learning system was lifelong learning, and lack of knowledge about virtual libraries was the reason for inadequate use of virtual libraries. The best format of virtual library from the administrators’ and students’ viewpoint, was portal document format (PDF. Conclusion: One of the most important function of a virtual library, is lifelong learning and empowering users to provide information and educational needs. The main reason for not setting up a virtual library is t lack of knowledge about it.

Monitoring the englacial fracture state using virtual-reflector seismology

Science.gov (United States)

Lindner, F.; Weemstra, C.; Walter, F.; Hadziioannou, C.

2017-12-01

Fracturing and changes in the englacial macroscopic water content change the elastic bulk properties of ice bodies. Small seismic velocity variations, resulting from such changes, can be measured using a technique called coda-wave interferometry. Here, coda refers to the later-arriving, multiply scattered waves. Often, this technique is applied to so-called virtual-source responses, which can be obtained using seismic interferometry (a simple crosscorrelation process). Compared to other media (e.g., the Earth's crust), however, ice bodies exhibit relatively little scattering. This complicates the application of coda-wave interferometry to the retrieved virtual-source responses. In this work, we therefore investigate the applicability of coda-wave interferometry to virtual-source responses obtained using two alternative seismic interferometric techniques, namely, seismic interferometry by multidimensional deconvolution (SI by MDD), and virtual-reflector seismology (VRS). To that end, we use synthetic data, as well as active-source glacier data acquired on Glacier de la Plaine Morte, Switzerland. Both SI by MDD and VRS allow the retrieval of more accurate virtual-source responses. In particular, the dependence of the retrieved virtual-source responses on the illumination pattern is reduced. We find that this results in more accurate glacial phase-velocity estimates. In addition, VRS introduces virtual reflections from a receiver contour (partly) enclosing the medium of interest. By acting as a sort of virtual reverberation, the coda resulting from the application of VRS significantly increases seismic monitoring capabilities, in particular in cases where natural scattering coda is not available.

Virtual Reality and the Virtual Library.

Science.gov (United States)

Oppenheim, Charles

1993-01-01

Explains virtual reality, including proper and improper uses of the term, and suggests ways that libraries might be affected by it. Highlights include elements of virtual reality systems; possible virtual reality applications, including architecture, the chemical industry, transport planning, armed forces, and entertainment; and the virtual…

From virtual environment to virtual community

NARCIS (Netherlands)

Nijholt, Antinus; Terano, Takao; Nishida, Toyoaki; Namatame, Akira; Tsumoto, Syusaku; Ohsawa, Yukido; Washio, Takashi

2001-01-01

We discuss a virtual reality theater environment and its transition to a virtual community by adding domain agents and by allowing multiple users to visit this environment. The environment has been built using VRML (Virtual Reality Modeling Language). We discuss how our ideas about this environment

Computer based virtual reality approach towards its application in an accidental emergency at nuclear power plant

International Nuclear Information System (INIS)

Yan Jun; Yao Qingshan

1999-01-01

Virtual reality is a computer based system for creating and receiving virtual world. As an emerging branch of computer discipline, this approach is extensively expanding and widely used in variety of industries such as national defence, research, engineering, medicine and air navigation. The author intends to present the fundamentals of virtual reality, in attempt to study some interested aspects for use in nuclear power emergency planning

The ability of ewes with lambs to learn a virtual fencing system.

Science.gov (United States)

Brunberg, E I; Bergslid, I K; Bøe, K E; Sørheim, K M

2017-11-01

The Nofence technology is a GPS-based virtual fencing system designed to keep sheep within predefined borders, without using physical fences. Sheep wearing a Nofence collar receive a sound signal when crossing the virtual border and a weak electric shock if continuing to walk out from the virtual enclosure. Two experiments testing the functionality of the Nofence system and a new learning protocol is described. In Experiment 1, nine ewes with their lambs were divided into groups of three and placed in an experimental enclosure with one Nofence border. During 2 days, there was a physical fence outside the border, during Day 3 the physical fence was removed and on Day 4, the border was moved to the other end of the enclosure. The sheep received between 6 and 20 shocks with an average of 10.9±2.0 (mean±SE) per ewe during all 4 days. The number of shocks decreased from 4.38±0.63 on Day 3 (when the physical fence was removed) to 1.5±0.71 on Day 4 (when the border was moved). The ewes spent on average 3%, 6%, 46% and 9% of their time outside the border on Days 1, 2, 3 and 4, respectively. In Experiment 2, 32 ewes, with and without lambs, were divided into groups of eight and placed in an experimental enclosure. On Day 1, the enclosure was fenced with three physical fences and one virtual border, which was then increased to two virtual borders on Day 2. To continue to Day 3, when there was supposed to be three virtual borders on the enclosure, at least 50% of the ewes in a group should have received a maximum of four shocks on Day 2. None of the groups reached this learning criterion and the experiment ended after Day 2. The sheep received 4.1±0.32 shocks on Day 1 and 4.7±0.28 shocks on Day 2. In total, 71% of the ewes received the maximum number of five shocks on Day 1 and 77% on Day 2. The individual ewes spent between 0% and 69.5% of Day 1 in the exclusion zone and between 0% and 64% on Day 2. In conclusion, it is too challenging to ensure an efficient learning

3D virtual facilities with interactive instructions for nuclear education and training

International Nuclear Information System (INIS)

Satoh, Yoshinori; Li, Ye; Zhu, Yuefeng; Rizwan-uddin

2015-01-01

Efficient and effective education and training of nuclear engineering students and future operators are critical for the safe operation and maintenance of nuclear power plants. Students and future operators used to receive some of the education and training at university laboratories and research reactors. With many university research reactors now shutdown, both students and future operators are deprived of this valuable training source. With an eye toward this need and to take advantage of recent developments in human machine interface technologies, we have focused on the development of 3D virtual laboratories for nuclear engineering education and training as well as to conduct virtual experiments. These virtual laboratories are expected to supplement currently available resources and education and training experiences. Resent focus is on adding interactivity and physics model to allow trainees to conduct virtual experiments. This paper reports some recent extensions to our virtual nuclear education laboratory and research reactor laboratory. These include head mounted display as well as hand tracking devices for virtual operations. (author)

Investigating the Impact of Virtual Communities on Furtherance of Customers’ Buying Behavior

Directory of Open Access Journals (Sweden)

Mohammad Fathian

2014-09-01

Full Text Available In recent years, virtual communities have been significantly popular and almost all of them are targeted for business profitability. In our study, the profitability of these communities for businesses has been analyzed from a commercial perspective. The study considers virtual community as a business model which can have a great impact on consumer purchase decision process. With respect to reference groups and word-of-mouth recommendations in virtual communities, contributing factors have been detected and a model of impacts and relationships between these factors has been presented. Hypotheses of the mentioned model are evaluated by making use of a questionnaire completed by 110 members of virtual communities. Using AMOS program and path analysis method, statistical analysis of received responses showed that factors such as virtual community's information quality, trust between people, sense of belonging, virtual community members’ perceived benefit and members’ permeability are effective to different degrees, and there is no significant relationship between social identity of members and their permeability.

Second Life: A Virtual Learning Center for the Study of Sharks

Directory of Open Access Journals (Sweden)

Tryfonas Papadamou

2011-06-01

Full Text Available In this work the educational capabilities of the virtual world Second Life are researched and tested. A virtual world is constructed to support education for sustainable development. The life and characteristics of the shark is studied as this fish has received a lot of negative publicity and is in the danger of extinction. A virtual museum was developed for this purpose. The research question is focused on whether it can be used effectively in a modern classroom and how difficult is for an educator to develop such an application. To achieve that, a number of learning activities were developed, a number of on line questionnaires were issued and a series of virtual meetings were held. Teachers used the application and answered the questionnaires. The entire effort was attempted through Internet exclusively.

A Virtual Assistant for Websites

OpenAIRE

Duizith, José Luiz Andrade; Lutheran University of Brazil; da Silva, Lizandro Kirst; ADS Digital; Brahm, Daniel Ribeiro; ADS Digital; Tagliassuchi, Gustavo; ADS Digital; Loh, Stanley; Lutheran University of Brazil ” ULBRA, Brasil Catholic University of Pelotas ” UCPEL, Brasil

2004-01-01

This work presents a Virtual Assistant (VA) whose main goal is to supply information for Websites users. AVA is a software system that interacts with persons through a Web browser, receiving textual questions and answering automatically without human intervention. The VA supplies information by looking for similar questions in a knowledge base and giving the corresponding answer. Artificial Intelligence techniques are employed in this matching process, to compare the user’s question aga...

An experiment on fear of public speaking in virtual reality.

Science.gov (United States)

Pertaub, D P; Slater, M; Barker, C

2001-01-01

Can virtual reality exposure therapy be used to treat people with social phobia? To answer this question it is vital to known if people will respond to virtual humans (avatars) in a virtual social setting in the same way they would to real humans. If someone is extremely anxious with real people, will they also be anxious when faced with simulated people, despite knowing that the avatars are computer generated? In [17] we described a small pilot study that placed 10 people before a virtual audience. The purpose was to assess the extent to which social anxiety, specifically fear of public speaking, was induced by the virtual audience and the extent of influence of degree of immersion (head mounted display or desktop monitor. The current paper describes a follow up study conducted with 40 subjects and the results clearly show that not only is social anxiety induced by the audience, but the degree of anxiety experienced is directly related to the type of virtual audience feedback the speaker receives. In particular, a hostile negative audience scenario was found to generate strong affect in speakers, regardless of whether or not they normally suffered from fear of public speaking.

A comparison of the use of virtual versus physical snapshots for supporting update-intensive workloads

DEFF Research Database (Denmark)

Šidlauskas, Darius; Jensen, Christian S.; Šaltenis, Simonas

2012-01-01

and one for the frequent and very localized updates. The snapshot that receives the updates is frequently made available to queries, so that queries see up-to-date data. The snapshots may be physical or virtual. Physical snapshots are created using the C library memcpy function. Virtual snapshots...

Super-virtual refraction interferometry: an engineering field data example

KAUST Repository

Hanafy, Sherif M.

2012-10-01

The theory of super-virtual refraction interferometry (SVI) was recently developed to enhance the signal-to-noise ratio (SNR) of far-offset traces in refraction surveys. This enhancement of the SNR is proportional to √N and can be as high as N if an iterative procedure is used. Here N is the number of post-critical shot positions that coincides with the receiver locations. We now demonstrate the SNR enhancement of super-virtual refraction traces for one engineering-scale synthetic data and two field seismic data sets. The field data are collected over a normal fault in Saudi Arabia. Results show that both the SNR of the super-virtual data set and the number of reliable first-arrival traveltime picks are significantly increased. © 2012 European Association of Geoscientists & Engineers.

Super-virtual refraction interferometry: an engineering field data example

KAUST Repository

Hanafy, Sherif M.; Alhagan, Ola

2012-01-01

The theory of super-virtual refraction interferometry (SVI) was recently developed to enhance the signal-to-noise ratio (SNR) of far-offset traces in refraction surveys. This enhancement of the SNR is proportional to √N and can be as high as N if an iterative procedure is used. Here N is the number of post-critical shot positions that coincides with the receiver locations. We now demonstrate the SNR enhancement of super-virtual refraction traces for one engineering-scale synthetic data and two field seismic data sets. The field data are collected over a normal fault in Saudi Arabia. Results show that both the SNR of the super-virtual data set and the number of reliable first-arrival traveltime picks are significantly increased. © 2012 European Association of Geoscientists & Engineers.

Higher operation temperature quadrant photon detectors of 2-11 μm wavelength radiation with large photosensitive areas

Science.gov (United States)

Pawluczyk, J.; Sosna, A.; Wojnowski, D.; Koźniewski, A.; Romanis, M.; Gawron, W.; Piotrowski, J.

2017-10-01

We report on the quadrant photon HgCdTe detectors optimized for 2-11 μm wavelength spectral range and Peltier or no cooling, and photosensitive area of a quad-cell of 1×1 to 4×4 mm. The devices are fabricated as photoconductors or multiple photovoltaic cells connected in series (PVM). The former are characterized by a relatively uniform photosensitive area. The PVM photovoltaic cells are distributed along the wafer surface, comprising a periodical stripe structure with a period of 20 μm. Within each period, there is an insensitive gap/trench spot of size close to the period, but becomes negligible for the optimal spot size comparable to a quadrant-cell area. The photoconductors produce 1/f noise with about 10 kHz knee frequency, due to bias necessary for their operation. The PVM photodiodes are typically operated at 0 V bias, so they generate no 1/f noise and operation from DC is enabled. At 230 K, upper corner frequency of 16 to 100 MHz is obtained for photoconductor and 60 to 80 MHz for PVM, normalized detectivity D* 6×107 cm×Hz1/2/W to >1.4×108 cm×Hz1/2/W for photoconductor and >1.7×108 cm·Hz1/2/W for PVM, allowing for position control of the radiation beam with submicron accuracy at 16 MHz, 10.6 μm wavelength of pulsed radiation spot of 0.8 mm dia at the close-to-maximal input radiation power density in a range of detector linear operation.

AN OUTER ARM IN THE SECOND GALACTIC QUADRANT: STRUCTURE

Energy Technology Data Exchange (ETDEWEB)

Du, Xinyu; Xu, Ye; Yang, Ji; Sun, Yan; Li, Facheng; Zhang, Shaobo; Zhou, Xin, E-mail: xydu@pmo.ac.cn, E-mail: xuye@pmo.ac.cn [Purple Mountain Observatory, Chinese Academy of Science, Nanjing 210008 (China)

2016-05-01

The lack of arm tracers, especially remote tracers, is one of the most difficult problems preventing us from studying the structure of the Milky Way. Fortunately, with its high-sensitivity CO survey, the Milky Way Imaging Scroll Painting (MWISP) project offers such an opportunity. Since completing about one-third of its mission, an area of l = [100, 150]°, b = [−3, 5]° has nearly been covered. The Outer arm of the Milky Way first clearly revealed its shape in the second galactic quadrant in the form of molecular gas—this is the first time that the Outer arm has been reported in such a large-scale mapping of molecular gas. Using the 115 GHz {sup 12}CO(1–0) data of MWISP at the LSR velocity ≃[−100, −60] km s{sup −1} and in the area mentioned above, we have detected 481 molecular clouds in total, and among them 332 (about 69%) are newly detected and 457 probably belong to the Outer arm. The total mass of the detected Outer arm clouds is ∼3.1 × 10{sup 6} M {sub ⊙}. Assuming that the spiral arm is a logarithmic spiral, the pitch angle is fitted as ∼13.°1. Besides combining both the CO data from MWISP and the 21 cm H i data from the Canadian Galactic Plane Survey (CGPS), the gas distribution, warp, and thickness of the Outer arm are also studied.

Quadrant Dynamic with Automatic Plateau Limit Histogram Equalization for Image Enhancement

Directory of Open Access Journals (Sweden)

P. Jagatheeswari

2014-01-01

Full Text Available The fundamental and important preprocessing stage in image processing is the image contrast enhancement technique. Histogram equalization is an effective contrast enhancement technique. In this paper, a histogram equalization based technique called quadrant dynamic with automatic plateau limit histogram equalization (QDAPLHE is introduced. In this method, a hybrid of dynamic and clipped histogram equalization methods are used to increase the brightness preservation and to reduce the overenhancement. Initially, the proposed QDAPLHE algorithm passes the input image through a median filter to remove the noises present in the image. Then the histogram of the filtered image is divided into four subhistograms while maintaining second separated point as the mean brightness. Then the clipping process is implemented by calculating automatically the plateau limit as the clipped level. The clipped portion of the histogram is modified to reduce the loss of image intensity value. Finally the clipped portion is redistributed uniformly to the entire dynamic range and the conventional histogram equalization is executed in each subhistogram independently. Based on the qualitative and the quantitative analysis, the QDAPLHE method outperforms some existing methods in literature.

Antiallergic effect of the atomized extract of rhizome of Curcuma longa, flowers of Cordia lutea and leaves of Annona muricata.

Science.gov (United States)

Arroyo-Acevedo, Jorge; Franco-Quino, Cesar; Ruiz-Ramirez, Eliberto; Chávez-Asmat, Roberto; Anampa-Guzmán, Andrea; Raéz-González, Ernesto; Cabanillas-Coral, José

2016-01-01

Allergies are a problem that greatly affects the population, and hence the use of antiallergic medications is fairly widespread. However, these drugs have many adverse effects. The use of medicinal plants could be an option, but they need to be evaluated. This study was designed to evaluate the antiallergic effect of the atomized extract of rhizome of Curcuma longa , flowers of Cordia lutea , and leaves of Annona muricata . Twenty-four New Zealand white albino rabbits were randomized into 2 groups. Group A received the atomized extract diluted in physiological saline (APS) and group B received it diluted in Freund's adjuvant (FA). Then, the back of each rabbit was divided into 4 quadrants. The A-I quadrant received only physiological saline. The A-I quadrants of each rabbit conformed the PS group. The following 3 quadrants received the APS in 10 μg/mL, 100 μg/mL, and 1,000 μg/mL, respectively. The B-I quadrant received only FA. The B-I quadrants of each rabbit conformed the FA group. The following 3 quadrants received the AFA in 10 μg/mL, 100 μg/mL, and 1,000 μg/mL, respectively. The occurrence of erythema and edema was recorded according to the Draize scoring system and the primary irritation index. After 72 hours, biopsies were performed. The AFA group presented significantly less erythema and edema compared to the FA group ( P <0.05). The histopathologic evaluation at 72 hours showed normal characteristics in the APS group. Considering the clinical and histopathological signs, we conclude that the administration of the atomized extract of rhizome of C. longa , flowers of C. lutea , and leaves of A. muricata lacks antigenic effect but could have an antiallergenic effect in a model of dermal irritation in rabbits.

Virtual Team Governance: Addressing the Governance Mechanisms and Virtual Team Performance

Science.gov (United States)

Zhan, Yihong; Bai, Yu; Liu, Ziheng

As technology has improved and collaborative software has been developed, virtual teams with geographically dispersed members spread across diverse physical locations have become increasingly prominent. Virtual team is supported by advancing communication technologies, which makes virtual teams able to largely transcend time and space. Virtual teams have changed the corporate landscape, which are more complex and dynamic than traditional teams since the members of virtual teams are spread on diverse geographical locations and their roles in the virtual team are different. Therefore, how to realize good governance of virtual team and arrive at good virtual team performance is becoming critical and challenging. Good virtual team governance is essential for a high-performance virtual team. This paper explores the performance and the governance mechanism of virtual team. It establishes a model to explain the relationship between the performance and the governance mechanisms in virtual teams. This paper is focusing on managing virtual teams. It aims to find the strategies to help business organizations to improve the performance of their virtual teams and arrive at the objectives of good virtual team management.

Mechanism of Action for Obtaining Job Offers With Virtual Reality Job Interview Training.

Science.gov (United States)

Smith, Matthew J; Smith, Justin D; Fleming, Michael F; Jordan, Neil; Brown, C Hendricks; Humm, Laura; Olsen, Dale; Bell, Morris D

2017-07-01

Four randomized controlled trials revealed that virtual-reality job interview training (VR-JIT) improved interviewing skills and the odds of obtaining a job offer among trainees with severe mental illness or autism spectrum disorder. This study assessed whether postintervention interviewing skills mediated the relationship between completion of virtual interviews and receiving job offers by six-month follow-up. VR-JIT trainees (N=79) completed pre- and posttest mock interviews and a brief survey approximately six months later to assess whether they received a job offer. As hypothesized, analyses indicated that the number of completed virtual interviews predicted greater posttest interviewing skills (β=.20, 95% posterior credible interval [PCI]=.08-.33), which in turn predicted trainees' obtaining a job offer (β=.28, 95% PCI=.01-.53). VR-JIT may provide a mechanism of action that helps trainees with various psychiatric diagnoses obtain job offers in the community. Future research can evaluate the community-based effectiveness of this novel intervention.

Super-virtual refraction interferometry: Field data example over a colluvial wedge

KAUST Repository

Hanafy, Sherif M.; Alhagan, Ola; Al-Tawash, Feras

2011-01-01

The theory of super-virtual refraction interferometry was recently developed to enhance the signal-to-noise ratio (SNR) of far-offset traces in refraction surveys. This enhancement of SNR is proportional to N, and can be as high as N if an iterative procedure is used. Here N is the number of post-critical shot positions that coincides with the receiver locations. We now demonstrate the enhancement of SNR of the super-virtual refraction traces for seismic data collected over a normal fault in Saudi Arabia. Results show that both the SNR of the super-virtual data set and the number of reliable first-arrival-traveltime picks are significantly increased. © 2011 Society of Exploration Geophysicists.

Study of II Galactic quadrant of Milky Way Galaxy using open clusters

Science.gov (United States)

Bisht, Devendra; Ganesh, Shashikiran; Baliyan, Kiran Singh; Yadav, Ramakant Singh; Durgapal, Alok

2018-04-01

We have made UBV I CCD observations for the open clusters Teutsch 1, Riddle 4 and Czernik 6 using 1.04-m Sampurnanand telescope located at the ARIES observatory (Manora peak, Nainital, India). We have used 2MASS JHKS data for the clusters Teutsch 126, Teutsch 54 and Czernik 3. For the estimation of fundamental parameters, we have plotted radial density profiles, colour-magnitude and colour-colour diagrams. Using these inputs, we have studied the structure of Milky Way Galaxy in the second Galactic quadrant. We have considered the open clusters that are younger than 1 Gyrs and lay in the longitude range from 90 to 180 deg. Our study shows that up to 3.5 Kpc, the Galactic disc bends towards the southern hemisphere while after 3.5 Kpc it bends towards the northern hemisphere. The distribution of reddening with longitude and age shows a decreasing trend with the longitude and age of the clusters. Our study also indicates that younger clusters have more reddening than older ones.

Nuclear plant's virtual simulation for on-line radioactive environment monitoring and dose assessment for personnel

International Nuclear Information System (INIS)

Mol, Antonio Carlos A.; Jorge, Carlos Alexandre F.; Lapa, Celso Marcelo F.

2009-01-01

This paper reports the use of nuclear plant's simulation for online dose rate monitoring and dose assessment for personnel, using virtual reality technology. The platform used for virtual simulation was adapted from a low cost game engine, taking advantage of all its image rendering capabilities, as well as the physics for movement and collision, and networking capabilities for multi-user interactive navigation. A real nuclear plant was virtually modeled and simulated, so that a number of users can navigate simultaneously in this virtual environment in first or third person view, each one receiving visual information about both the radiation dose rate in each actual position, and the radiation dose received. Currently, this research and development activity has been extended to consider also on-line measurements collected from radiation monitors installed in the real plant that feed the simulation platform with dose rate data, through a TCP/IP network. Results are shown and commented, and other improvements are discussed, as the execution of a more detailed dose rate mapping campaign.

Towards monitoring the englacial fracture state using virtual-reflector seismology

Science.gov (United States)

Lindner, F.; Weemstra, C.; Walter, F.; Hadziioannou, C.

2018-04-01

In seismology, coda wave interferometry (CWI) is an effective tool to monitor time-lapse changes using later arriving, multiply scattered coda waves. Typically, CWI relies on an estimate of the medium's impulse response. The latter is retrieved through simple time-averaging of receiver-receiver cross-correlations of the ambient field, i.e. seismic interferometry (SI). In general, the coda are induced by heterogeneities in the Earth. Being comparatively homogeneous, however, ice bodies such as glaciers and ice sheets exhibit little scattering. In addition, the temporal stability of the time-averaged cross-correlations suffers from temporal variations in the distribution and amplitude of the passive seismic sources. Consequently, application of CWI to ice bodies is currently limited. Nevertheless, fracturing and changes in the englacial macroscopic water content alter the bulk elastic properties of ice bodies, which can be monitored with cryoseismological measurements. To overcome the current limited applicability of CWI to ice bodies, we therefore introduce virtual-reflector seismology (VRS). VRS relies on a so-called multidimensional deconvolution (MDD) process of the time-averaged crosscorrelations. The technique results in the retrieval of a medium response that includes virtual reflections from a contour of receivers enclosing the region of interest (i.e., the region to be monitored). The virtual reflections can be interpreted as artificial coda replacing the (lacking) natural scattered coda. Hence, this artificial coda might be exploited for the purpose of CWI. From an implementation point of view, VRS is similar to SI by MDD, which, as its name suggests, also relies on a multidimensional deconvolution process. SI by MDD, however, does not generate additional virtual reflections. Advantageously, both techniques mitigate spurious coda changes associated with temporal variations in the distribution and amplitude of the passive seismic sources. In this work, we

Innovative application of virtual display technique in virtual museum

Science.gov (United States)

Zhang, Jiankang

2017-09-01

Virtual museum refers to display and simulate the functions of real museum on the Internet in the form of 3 Dimensions virtual reality by applying interactive programs. Based on Virtual Reality Modeling Language, virtual museum building and its effective interaction with the offline museum lie in making full use of 3 Dimensions panorama technique, virtual reality technique and augmented reality technique, and innovatively taking advantages of dynamic environment modeling technique, real-time 3 Dimensions graphics generating technique, system integration technique and other key virtual reality techniques to make sure the overall design of virtual museum.3 Dimensions panorama technique, also known as panoramic photography or virtual reality, is a technique based on static images of the reality. Virtual reality technique is a kind of computer simulation system which can create and experience the interactive 3 Dimensions dynamic visual world. Augmented reality, also known as mixed reality, is a technique which simulates and mixes the information (visual, sound, taste, touch, etc.) that is difficult for human to experience in reality. These technologies make virtual museum come true. It will not only bring better experience and convenience to the public, but also be conducive to improve the influence and cultural functions of the real museum.

Virtual Trondheim: A Virtual Environment for Tourism and Education

OpenAIRE

Jose, Dawn Alphonse

2015-01-01

The purpose of this study is to investigate whether educational activities in tourism can be supported by virtual reality technologies, using virtual world frameworks. Settings of virtual world of SecondLife and a recent Virtual Reality technology known as Oculus Rift were used in the thesis work with the city of Trondheim as the main context. Theoretical studies on Virtual Reality systems were conducted and data for the research were obtained through empirical studies condu...

Virtual Trackballs Revisited

DEFF Research Database (Denmark)

Henriksen, Knud; Sporring, Jon; Hornbæk, Kasper

2004-01-01

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......'s virtual trackball is inhomogeneous and discontinuous with consequences for usability. Finally, we review Bell's virtual trackball [CHECK END OF SENTENCE] and discuss studies of the usability of virtual trackballs....

LibAnswers: Analyzing tickets (questions) to improve our library's virtual reference service(s)

KAUST Repository

Ramli, Rindra M.

2017-05-01

Analyze the questions received in LibAnswers (ticketing system) in order to improve the quality of our virtual reference services. Tickets that were received between June 2015 to April 2017 were analyzed and categorized. It was noted that most questions asked revolved around electronic resources issues as well as circulation/access issues.

LibAnswers: Analyzing tickets (questions) to improve our library's virtual reference service(s)

KAUST Repository

Ramli, Rindra M.; Ba-Rayyan, Faten A.

2017-01-01

Analyze the questions received in LibAnswers (ticketing system) in order to improve the quality of our virtual reference services. Tickets that were received between June 2015 to April 2017 were analyzed and categorized. It was noted that most questions asked revolved around electronic resources issues as well as circulation/access issues.

Personal Virtual Libraries

Science.gov (United States)

Pappas, Marjorie L.

2004-01-01

Virtual libraries are becoming more and more common. Most states have a virtual library. A growing number of public libraries have a virtual presence on the Web. Virtual libraries are a growing addition to school library media collections. The next logical step would be personal virtual libraries. A personal virtual library (PVL) is a collection…

The effect of virtual reality training on unilateral spatial neglect in stroke patients.

Science.gov (United States)

Kim, Yong Mi; Chun, Min Ho; Yun, Gi Jeong; Song, Young Jin; Young, Han Eun

2011-06-01

To investigate the effect of virtual reality training on unilateral spatial neglect in stroke patients. Twenty-four stroke patients (14 males and 10 females, mean age=64.7) who had unilateral spatial neglect as a result of right hemisphere stroke were recruited. All patients were randomly assigned to either the virtual reality (VR) group (n=12) or the control group (n=12). The VR group received VR training, which stimulated the left side of their bodies. The control group received conventional neglect therapy such as visual scanning training. Both groups received therapy for 30 minutes a day, five days per week for three weeks. Outcome measurements included star cancellation test, line bisection test, Catherine Bergego scale (CBS), and the Korean version of modified Barthel index (K-MBI). These measurements were taken before and after treatment. There were no significant differences in the baseline characteristics and initial values between the two groups. The changes in star cancellation test results and CBS in the VR group were significantly higher than those of the control group after treatment. The changes in line bisection test score and the K-MBI in the VR group were not statistically significant. This study suggests that virtual reality training may be a beneficial therapeutic technique on unilateral spatial neglect in stroke patients.

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

Virtual Nursing Intervention Adjunctive to Conventional Care: The Experience of Persons Living With HIV

Science.gov (United States)

Rouleau, Geneviève; Ramirez-Garcia, Pilar; Bourbonnais, Anne

2015-01-01

Background Persons living with HIV (PLHIV) must adhere optimally to antiretroviral therapy (ART) on a daily basis and for their lifetime to maintain an undetectable viral load, allowing them to preserve their health. Taking advantage of the opportunity that information and communication technologies provide to broaden intervention modalities and intensify clinical follow-up, a virtual nursing intervention consisting of four interactive computer sessions was developed to empower PLHIV to manage their ART and symptoms optimally. Compared with other types of information and communication technologies-assisted interventions such as text messages, HIV Treatment, Virtual Nursing Assistance and Education (VIH-TAVIE) requires a certain degree of active engagement on the part of the user to develop and strengthen the self-management skills to optimize adherence. After the intervention’s impact on ART adherence was measured quantitatively, a qualitative study was undertaken to describe how users experience the intervention. Understanding how PLHIV perceive being assisted asynchronously by a virtual nurse was of particular interest. Objective The objective of the study was to explore and describe how PLHIV experience VIH-TAVIE, that is, receiving customized asynchronous accompaniment via a virtual nurse. Methods A qualitative study was conducted with 26 PLHIV (20 men, 6 women) who received all four VIH-TAVIE sessions. Participants had been diagnosed with HIV 14 years earlier on average and had been on ART for a mean period of 10 years. The sessions lasted 20-30 minutes each and were received two weeks apart. They are hosted by a virtual nurse who engages the user in a self-management skills-learning process for the purpose of treatment adherence. Semistructured interviews were conducted lasting 30-40 minutes to get participants to share their experience of the intervention through personal stories and what they thought and felt during their participation. Data were analyzed

Virtual Nursing Intervention Adjunctive to Conventional Care: The Experience of Persons Living With HIV.

Science.gov (United States)

Côté, José; Rouleau, Geneviève; Ramirez-Garcia, Pilar; Bourbonnais, Anne

2015-10-20

Persons living with HIV (PLHIV) must adhere optimally to antiretroviral therapy (ART) on a daily basis and for their lifetime to maintain an undetectable viral load, allowing them to preserve their health. Taking advantage of the opportunity that information and communication technologies provide to broaden intervention modalities and intensify clinical follow-up, a virtual nursing intervention consisting of four interactive computer sessions was developed to empower PLHIV to manage their ART and symptoms optimally. Compared with other types of information and communication technologies-assisted interventions such as text messages, HIV Treatment, Virtual Nursing Assistance and Education (VIH-TAVIE) requires a certain degree of active engagement on the part of the user to develop and strengthen the self-management skills to optimize adherence. After the intervention's impact on ART adherence was measured quantitatively, a qualitative study was undertaken to describe how users experience the intervention. Understanding how PLHIV perceive being assisted asynchronously by a virtual nurse was of particular interest. The objective of the study was to explore and describe how PLHIV experience VIH-TAVIE, that is, receiving customized asynchronous accompaniment via a virtual nurse. A qualitative study was conducted with 26 PLHIV (20 men, 6 women) who received all four VIH-TAVIE sessions. Participants had been diagnosed with HIV 14 years earlier on average and had been on ART for a mean period of 10 years. The sessions lasted 20-30 minutes each and were received two weeks apart. They are hosted by a virtual nurse who engages the user in a self-management skills-learning process for the purpose of treatment adherence. Semistructured interviews were conducted lasting 30-40 minutes to get participants to share their experience of the intervention through personal stories and what they thought and felt during their participation. Data were analyzed using Miles and Huberman

Effect of virtual reality on cognition in stroke patients.

Science.gov (United States)

Kim, Bo Ryun; Chun, Min Ho; Kim, Lee Suk; Park, Ji Young

2011-08-01

To investigate the effect of virtual reality on the recovery of cognitive impairment in stroke patients. Twenty-eight patients (11 males and 17 females, mean age 64.2) with cognitive impairment following stroke were recruited for this study. All patients were randomly assigned to one of two groups, the virtual reality (VR) group (n=15) or the control group (n=13). The VR group received both virtual reality training and computer-based cognitive rehabilitation, whereas the control group received only computer-based cognitive rehabilitation. To measure, activity of daily living cognitive and motor functions, the following assessment tools were used: computerized neuropsychological test and the Tower of London (TOL) test for cognitive function assessment, Korean-Modified Barthel index (K-MBI) for functional status evaluation, and the motricity index (MI) for motor function assessment. All recruited patients underwent these evaluations before rehabilitation and four weeks after rehabilitation. The VR group showed significant improvement in the K-MMSE, visual and auditory continuous performance tests (CPT), forward digit span test (DST), forward and backward visual span tests (VST), visual and verbal learning tests, TOL, K-MBI, and MI scores, while the control group showed significant improvement in the K-MMSE, forward DST, visual and verbal learning tests, trail-making test-type A, TOL, K-MBI, and MI scores after rehabilitation. The changes in the visual CPT and backward VST in the VR group after rehabilitation were significantly higher than those in the control group. Our findings suggest that virtual reality training combined with computer-based cognitive rehabilitation may be of additional benefit for treating cognitive impairment in stroke patients.

Supporting document for the Southeast Quadrant historical tank content estimate report for SY-tank farm

International Nuclear Information System (INIS)

Brevick, C.H.; Gaddis, L.A.; Consort, S.D.

1995-01-01

Historical Tank Content Estimate of the Southeast Quadrant provides historical evaluations on a tank by tank basis of the radioactive mixed wastes stored in the underground double-shell tanks of the Hanford 200 East and West Areas. This report summarizes historical information such as waste history, temperature profiles, psychrometric data, tank integrity, inventory estimates and tank level history on a tank by tank basis. Tank Farm aerial photos and in-tank photos of each tank are provided. A brief description of instrumentation methods used for waste tank surveillance are included. Components of the data management effort, such as Waste Status and Transaction Record Summary, Tank Layer Model, Supernatant Mixing Model, Defined Waste Types, and Inventory Estimates which generate these tank content estimates, are also given in this report

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 ...

Virtual Exploratories

DEFF Research Database (Denmark)

Jensen, Sisse Siggaard

2006-01-01

-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...... the design and activity of the advanced virtual worlds and role-playing games, then the empirical research on the actors’ activity, while they are acting, is an important precondition to it. A step towards the conception of such a designing strategy for virtual exploratories is currently pursued....... [1] The research project: Actors and Avatars Communicating in Virtual Worlds – an Empirical Analysis of Actors’ Sense-making Strategies When Based on a Communication Theoretical Approach’ (2006-2007) is supported...

HIGH-EFFICIENCY INFRARED RECEIVER

Directory of Open Access Journals (Sweden)

A. K. Esman

2016-01-01

Full Text Available Recent research and development show promising use of high-performance solid-state receivers of the electromagnetic radiation. These receivers are based on the low-barrier Schottky diodes. The approach to the design of the receivers on the basis of delta-doped low-barrier Schottky diodes with beam leads without bias is especially actively developing because for uncooled receivers of the microwave radiation these diodes have virtually no competition. The purpose of this work is to improve the main parameters and characteristics that determine the practical relevance of the receivers of mid-infrared electromagnetic radiation at the operating room temperature by modifying the electrodes configuration of the diode and optimizing the distance between them. Proposed original design solution of the integrated receiver of mid-infrared radiation on the basis of the low-barrier Schottky diodes with beam leads allows to effectively adjust its main parameters and characteristics. Simulation of the electromagnetic characteristics of the proposed receiver by using the software package HFSS with the basic algorithm of a finite element method which implemented to calculate the behavior of electromagnetic fields on an arbitrary geometry with a predetermined material properties have shown that when the inner parts of the electrodes of the low-barrier Schottky diode is performed in the concentric elliptical convex-concave shape, it can be reduce the reflection losses to -57.75 dB and the standing wave ratio to 1.003 while increasing the directivity up to 23 at a wavelength of 6.09 μm. At this time, the rounded radii of the inner parts of the anode and cathode electrodes are equal 212 nm and 318 nm respectively and the gap setting between them is 106 nm. These parameters will improve the efficiency of the developed infrared optical-promising and electronic equipment for various purposes intended for work in the mid-infrared wavelength range. 

VIRTUAL EXPERIMENTAL ANALYSIS ON CLEANING ELEMENT OF SUGARCANE HARVESTER

Institute of Scientific and Technical Information of China (English)

Ma Fanglan; Li Shangping; He Yulin; Meng Yanmei; Chen Weixu

2005-01-01

The laws of influence of different factors have been analyzed in order to enhance the working efficiency and fatigue life of the cleaning element in brush shape of the sugarcane harvester.Based on the principle of orthogonal experiment design, the virtual-orthogonal-experimental analysis for the cleaning element is carried out on the finite element analysis (FEA) software-ANSYS after analyzing the nonlinear structural behavior in the working procedure. The results are analyzed with the overall balancing method, and then the optimal combination is got, which is made up of different levels of different factors. Also the optimal combination of design parameters of the cleaning element received from the virtual experimental analysis is conducted an experiment to confirm that the virtual analysis model and results are right, and the effect of factors on the function of the cleaning element is obtained by more analysis and further optimizing.

Analysis of E-mail Transactions in Virtual Reference Services

Directory of Open Access Journals (Sweden)

Astutik Nur Qomariyah

2018-01-01

Full Text Available Today, the use of traditional reference desk in the academic libraries has been rarely used, thus expanding or even move to a virtual reference service. A minimum level of virtual reference services are provided in the academic library is currently in general is the electronic mail (e-mail. One of the academic library specifically provide virtual reference services via e-mail is a Petra Christian University (PCU Library (refdesk@petra.ac.id.. In such services librarians provide assistance to users in finding information and answer questions. This study aimed to analyze the transaction reference services virtually through e-mail at the PCU Library, with a view of the types of questions based on user background, the writing style of language communication interaction used based on user background, and cultural values are revealed behind the user in virtual reference services (e-mail. This study uses content analysis (content analysis of the transcript e-mail received librarians of reference services began March 10 until June 16, 2015. The results showed that the types of questions asked in reference service virtual (e-mail in the Library UK Petra include: specific search, access online resources, operation of online resources, policies and procedures for services, and library holdings with background the student (PCU and non-PCU, faculty, and librarians. Based on the background of users found that overall more types of questions asked in virtual reference services (e-mail is a problem of access to online resources, and generally submitted by the students. Then, the writing style of the user's language in interaction reference service virtual (e-mail tends to be formal, which includes the word greeting, the message will be delivered, and regards cover, either by the student (PCU and non-PCU, lecturer, or librarians. While cultural values that revealed the background behind the user in virtual reference services (e-mail is obedience, courtesy and

L’intermodalità a supporto della riduzione dell’impatto ambientale dei trasporti: il caso dell’interporto quadrante Europa di Verona

OpenAIRE

Chimenti, Matteo; Dal Dosso, Michele

2015-01-01

Il presente paper si pone l’obiettivo di analizzare l’impatto delle “esternalità” dei trasporti sull’ambiente e sulla società. Nello specifico l’analisi verterà sul sistema interportuale italiano, quale strumento strategico per incrementare la mobilità sostenibile del futuro. Lo studio si concentrerà dapprima su di una panoramica del disegno dell’interportualità italiana per poi focalizzarsi sull’Interporto Quadrante Europa di Verona, che diverrà il case study del presente paper. Tale s...

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.

Academic Library Services in Virtual Worlds: An Examination of the Potential for Library Services in Immersive Environments

Science.gov (United States)

Ryan, Jenna; Porter, Marjorie; Miller, Rebecca

2010-01-01

Current literature on libraries is abundant with articles about the uses and the potential of new interactive communication technology, including Web 2.0 tools. Recently, the advent and use of virtual worlds have received top billing in these works. Many library institutions are exploring these virtual environments; this exploration and the…

Sensitivity-based virtual fields for the non-linear virtual fields method

Science.gov (United States)

Marek, Aleksander; Davis, Frances M.; Pierron, Fabrice

2017-09-01

The virtual fields method is an approach to inversely identify material parameters using full-field deformation data. In this manuscript, a new set of automatically-defined virtual fields for non-linear constitutive models has been proposed. These new sensitivity-based virtual fields reduce the influence of noise on the parameter identification. The sensitivity-based virtual fields were applied to a numerical example involving small strain plasticity; however, the general formulation derived for these virtual fields is applicable to any non-linear constitutive model. To quantify the improvement offered by these new virtual fields, they were compared with stiffness-based and manually defined virtual fields. The proposed sensitivity-based virtual fields were consistently able to identify plastic model parameters and outperform the stiffness-based and manually defined virtual fields when the data was corrupted by noise.

On virtual displacement and virtual work in Lagrangian dynamics

International Nuclear Information System (INIS)

Ray, Subhankar; Shamanna, J

2006-01-01

The confusion and ambiguity encountered by students in understanding virtual displacement and virtual work is discussed in this paper. A definition of virtual displacement is presented that allows one to express them explicitly for holonomic (velocity independent), non-holonomic (velocity dependent), scleronomous (time independent) and rheonomous (time dependent) constraints. It is observed that for holonomic, scleronomous constraints, the virtual displacements are the displacements allowed by the constraints. However, this is not so for a general class of constraints. For simple physical systems, it is shown that the work done by the constraint forces on virtual displacements is zero. This motivates Lagrange's extension of d'Alembert's principle to a system of particles in constrained motion. However, a similar zero work principle does not hold for the allowed displacements. It is also demonstrated that d'Alembert's principle of zero virtual work is necessary for the solvability of a constrained mechanical problem. We identify this special class of constraints, physically realized and solvable, as the ideal constraints. The concept of virtual displacement and the principle of zero virtual work by constraint forces are central to both Lagrange's method of undetermined multipliers and Lagrange's equations in generalized coordinates

Virtual Reality

Science.gov (United States)

1993-04-01

until exhausted. SECURITY CLASSIFICATION OF THIS PAGE All other editions are obsolete. UNCLASSIFIED " VIRTUAL REALITY JAMES F. DAILEY, LIEUTENANT COLONEL...US" This paper reviews the exciting field of virtual reality . The author describes the basic concepts of virtual reality and finds that its numerous...potential benefits to society could revolutionize everyday life. The various components that make up a virtual reality system are described in detail

Framework for Virtual Cognitive Experiment in Virtual Geographic Environments

Directory of Open Access Journals (Sweden)

Fan Zhang

2018-01-01

Full Text Available Virtual Geographic Environment Cognition is the attempt to understand the human cognition of surface features, geographic processes, and human behaviour, as well as their relationships in the real world. From the perspective of human cognition behaviour analysis and simulation, previous work in Virtual Geographic Environments (VGEs has focused mostly on representing and simulating the real world to create an ‘interpretive’ virtual world and improve an individual’s active cognition. In terms of reactive cognition, building a user ‘evaluative’ environment in a complex virtual experiment is a necessary yet challenging task. This paper discusses the outlook of VGEs and proposes a framework for virtual cognitive experiments. The framework not only employs immersive virtual environment technology to create a realistic virtual world but also involves a responsive mechanism to record the user’s cognitive activities during the experiment. Based on the framework, this paper presents two potential implementation methods: first, training a deep learning model with several hundred thousand street view images scored by online volunteers, with further analysis of which visual factors produce a sense of safety for the individual, and second, creating an immersive virtual environment and Electroencephalogram (EEG-based experimental paradigm to both record and analyse the brain activity of a user and explore what type of virtual environment is more suitable and comfortable. Finally, we present some preliminary findings based on the first method.

An Overview of Virtual Acoustic Simulation of Aircraft Flyover Noise

Science.gov (United States)

Rizzi, Stephen A.

2013-01-01

Methods for testing human subject response to aircraft flyover noise have greatly advanced in recent years as a result of advances in simulation technology. Capabilities have been developed which now allow subjects to be immersed both visually and aurally in a three-dimensional, virtual environment. While suitable for displaying recorded aircraft noise, the true potential is found when synthesizing aircraft flyover noise because it allows the flexibility and freedom to study sounds from aircraft not yet flown. A virtual acoustic simulation method is described which is built upon prediction-based source noise synthesis, engineering-based propagation modeling, and empirically-based receiver modeling. This source-path-receiver paradigm allows complete control over all aspects of flyover auralization. With this capability, it is now possible to assess human response to flyover noise by systematically evaluating source noise reductions within the context of a system level simulation. Examples of auralized flyover noise and movie clips representative of an immersive aircraft flyover environment are made in the presentation.

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.

Teaching with technology: automatically receiving information from the internet and web.

Science.gov (United States)

Wink, Diane M

2010-01-01

In this bimonthly series, the author examines how nurse educators can use the Internet and Web-based computer technologies such as search, communication, and collaborative writing tools, social networking and social bookmarking sites, virtual worlds, and Web-based teaching and learning programs. This article presents information and tools related to automatically receiving information from the Internet and Web.

Analysis of E-mail Transactions in Virtual Reference Services

Directory of Open Access Journals (Sweden)

Astutik Nur Qomariyah

2016-01-01

Full Text Available Today, the use of traditional reference desk in the academic libraries has been rarely used, thus expanding or even move to a virtual reference service. A minimum level of virtual reference services are provided in the academic library is currently in general is the electronic mail (e-mail. One of the academic library specifically provide virtual reference services via e-mail is a Petra Christian University (PCU Library (ref-desk@petra.ac.id.. In such services librarians provide assistance to users in finding information and answer questions. This study aimed to analyze the transaction reference services virtually through e-mail at the PCU Library, with a view of the types of questions based on user background, the writing style of language communication interaction used based on user background, and cultural values are revealed behind the user in virtual reference services (e-mail. This study uses content analysis (content analysis of the transcript e-mail received librarians of reference services began March 10 until June 16, 2015. The results showed that the types of questions asked in reference service virtual (e-mail in the Library UK Petra include: specific search, access online resources, operation of online resources, policies and procedures for services, and library holdings with background the student (PCU and non-PCU, faculty, and librarians. Based on the background of users found that overall more types of questions asked in virtual reference services (e-mail is a problem of access to online resources, and generally submitted by the students. Then, the writing style of the user's language in interaction reference service virtual (e-mail tends to be formal, which includes the word greeting, the message will be delivered, and regards cover, either by the student (PCU and non-PCU, lecturer, or librarians. While cultural values that revealed the background behind the user in virtual reference services (e-mail is obedience, courtesy and

Virtual Box

DEFF Research Database (Denmark)

Davis, Hilary; Skov, Mikael B.; Stougaard, Malthe

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...

Virtual scarce water embodied in inter-provincial electricity transmission in China

International Nuclear Information System (INIS)

Zhang, Chao; Zhong, Lijin; Liang, Sai; Sanders, Kelly T.; Wang, Jiao; Xu, Ming

2017-01-01

Highlights: • Virtual water in inter-provincial electricity transmission in China is calculated. • A Water Stress Index is used to reflect relative scarcity of water consumption. • West Inner Mongolia is the largest exporter of scarce water. • Hebei, Beijing and Shandong are the three largest receivers of scarce water. - Abstract: Intra-national electricity transmission drives virtual water transfer from electricity production regions to electricity consumption regions. In China, the water-intensive thermoelectric power industry is expanding quickly in many water-scarce energy production hubs in northern and northwestern provinces. This study constructed a node-flow model of inter-provincial electricity transmission to investigate the virtual water and scarcity-adjusted virtual water (or virtual scarce water) embodied in the electricity transmission network. It is revealed that total inter-provincial virtual water transfer embodied in electricity transmission was 623 million m"3 in 2011, equivalent to 12.7% of the national total thermoelectric water consumption. The top three largest single virtual water flows are West Inner Mongolia-to-Beijing (44 million m"3), East Inner Mongolia-to-Liaoning (39 million m"3), and Guizhou-to-Guangdong (37 million m"3). If the actual volumes of consumptive water use are translated into scarcity-adjusted water consumption based on Water Stress Index, West Inner Mongolia (81 million m"3), Shanxi (63 million m"3) and Ningxia (30 million m"3) become the top three exporters of virtual scarce water. Many ongoing long-distance electricity transmission projects in China will enlarge the scale of scarce water outflows from northwestern regions and potentially increase their water stress.

Combining inter-source seismic interferometry and source-receiver interferometry for deep local imaging

NARCIS (Netherlands)

Liu, Y.; Arntsen, B.; Wapenaar, C.P.A.; Van der Neut, J.R.

2014-01-01

The virtual source method has been applied successfully to retrieve the impulse response between pairs of receivers in the subsurface. This method is further improved by an updown separation prior to the crosscorrelation to suppress the reflections from the overburden and the free surface. In a

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...

The Effect of Virtual Reality Training on Unilateral Spatial Neglect in Stroke Patients

OpenAIRE

Kim, Yong Mi; Chun, Min Ho; Yun, Gi Jeong; Song, Young Jin; Young, Han Eun

2011-01-01

Objective To investigate the effect of virtual reality training on unilateral spatial neglect in stroke patients. Method Twenty-four stroke patients (14 males and 10 females, mean age=64.7) who had unilateral spatial neglect as a result of right hemisphere stroke were recruited. All patients were randomly assigned to either the virtual reality (VR) group (n=12) or the control group (n=12). The VR group received VR training, which stimulated the left side of their bodies. The control group rec...

The number of zero solutions for complex canonical differential equation of second order with constant coefficients in the first quadrant

Directory of Open Access Journals (Sweden)

Vujaković Jelena

2016-01-01

Full Text Available The study of complex differential equations in recent years has opened up some of questions concerning the determination of the frequency of zero solutions, the distribution of zero, oscillation of the solution, asymptotic behavior, rank growth and so on. Besides, this is solved by only some classes of differential equations. In this paper, our aim was to determine the number of zeros and their arrangement in the first quadrant, for the complex canonical differential equation of the second order. The accuracy of our results, we illustrate with two examples.

A virtual network computer's optical storage virtualization scheme

Science.gov (United States)

Wang, Jianzong; Hu, Huaixiang; Wan, Jiguang; Wang, Peng

2008-12-01

In this paper, we present the architecture and implementation of a virtual network computers' (VNC) optical storage virtualization scheme called VOSV. Its task is to manage the mapping of virtual optical storage to physical optical storage, a technique known as optical storage virtualization. The design of VOSV aims at the optical storage resources of different clients and servers that have high read-sharing patterns. VOSV uses several schemes such as a two-level Cache mechanism, a VNC server embedded module and the iSCSI protocols to improve the performance. The results measured on the prototype are encouraging, and indicating that VOSV provides the high I/O performance.

Virtual bronchoscopy

International Nuclear Information System (INIS)

Rogalla, P.; Meiri, N.; Hamm, B.; Rueckert, J.C.; Schmidt, B.; Witt, C.

2001-01-01

Flexible bronchoscopy represents a clinically well-established invasive diagnostic tool. Virtual bronchoscopies, calculated from thin-slice CT sections, allow astonishing immitations of reality although principal differences exist between both technologies: the Fact that colour representation is artificial and concommitant interventions are impossible limits the clinical use of virtual bronchoscopy. However, its value increases when calculations can be attained within minutes due to technological advancements, and when virtually any chest CT is suitable for further postprocessing. Indications, findings and the clinical role of virtual bronchoscopy are discussed. (orig.) [de

Virtual button interface

Science.gov (United States)

Jones, J.S.

1999-01-12

An apparatus and method of issuing commands to a computer by a user interfacing with a virtual reality environment are disclosed. To issue a command, the user directs gaze at a virtual button within the virtual reality environment, causing a perceptible change in the virtual button, which then sends a command corresponding to the virtual button to the computer, optionally after a confirming action is performed by the user, such as depressing a thumb switch. 4 figs.

[Clinical application of accurate placement of lumbar pedicle screws using three-dimensional printing navigational templates under Quadrant system].

Science.gov (United States)

Chen, Xuanhuang; Yu, Zhengxi; Wu, Changfu; Li, Xing; Chen, Xu; Zhang, Guodong; Zheng, Zugao; Lin, Haibin

2017-02-01

To explore the feasibility and the effectiveness of the accurate placement of lumbar pedicle screws using three-dimensional (3D) printing navigational templates in Quadrant minimally invasive system. The L 1-5 spines of 12 adult cadavers were scanned using CT. The 3D models of the lumbar spines were established. The screw trajectory was designed to pass through the central axis of the pedicle by using Mimics software. The navigational template was designed and 3D-printed according to the bony surface where the soft tissues could be removed. The placed screws were scanned using CT to create the 3D model again after operation. The 3D models of the designed trajectory and the placed screws were registered to evaluate the placed screws coincidence rate. Between November 2014 and November 2015, 31 patients with lumbar instability accepted surgery assisted with 3D-printing navigation module under Quadrant minimally invasive system. There were 14 males and 17 females, aged from 42 to 60 years, with an average of 45.2 years. The disease duration was 6-13 months (mean, 8.8 months). Single segment was involved in 15 cases, two segments in 13 cases, and three segments in 3 cases. Preoperative visual analogue scale (VAS) was 7.59±1.04; Oswestry disability index (ODI) was 76.21±5.82; and the Japanese Orthopaedic Association (JOA) score was 9.21±1.64. A total of 120 screws were placed in 12 cadavers specimens. The coincidence rate of placed screw was 100%. A total of 162 screws were implanted in 31 patients. The operation time was 65-147 minutes (mean, 102.23 minutes); the intraoperative blood loss was 50-116 mL (mean, 78.20 mL); and the intraoperative radiation exposure time was 8-54 seconds (mean, 42 seconds). At 3-7 days after operation, CT showed that the coincidence rate of the placed screws was 98.15% (159/162). At 4 weeks after operation, VAS, ODI, and JOA score were 2.24±0.80, 29.17±2.50, and 23.43±1.14 respectively, showing significant differences when compared

Virtual Web Services

OpenAIRE

Rykowski, Jarogniew

2007-01-01

In this paper we propose an application of software agents to provide Virtual Web Services. A Virtual Web Service is a linked collection of several real and/or virtual Web Services, and public and private agents, accessed by the user in the same way as a single real Web Service. A Virtual Web Service allows unrestricted comparison, information merging, pipelining, etc., of data coming from different sources and in different forms. Detailed architecture and functionality of a single Virtual We...

A virtual environment for simulation of radiological accidents

International Nuclear Information System (INIS)

Silva, Tadeu Augusto de Almeida; Farias, Oscar Luiz Monteiro de

2013-01-01

A virtual environment is a computer environment, representative of a subset of the real world, and where models of the real world entities, process and events are included in a virtual (three-dimensional) space. Virtual environments are ideal tools for simulation of certain critical processes, such as radiological accidents, where human beings or properties can suffer irreversible or long term damages. Radiological accidents are characterized by the significant exposure to radiation of specialized workers and general public. The early detection of a radiological accident and the determination of its possible extension are essential factors for the planning of prompt answers and emergency actions. This paper proposes the integration of georeferenced representation of the three-dimensional space and agent-based models, with the objective to construct virtual environments that have the capacity to simulate radiological accidents. The three-dimensional georeferenced representations of space candidates are: 1) the spatial representation of traditional geographical information systems (GIS); 2) the representation adopted by Google Maps®. Adding agents to these spatial representations allow us to simulate radiological accidents, quantify the doses received by members of the public, obtain a possible spatial distribution of people contaminated, estimate the number of contaminated individuals, estimate the impact on the health-network, estimate environmental impacts, generate exclusion zones, build alternative scenarios and train staff to deal with radiological accidents. (author)

A virtual environment for simulation of radiological accidents

Energy Technology Data Exchange (ETDEWEB)

Silva, Tadeu Augusto de Almeida, E-mail: tedsilva@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Farias, Oscar Luiz Monteiro de, E-mail: fariasol@eng.uerj.br [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil)

2013-07-01

A virtual environment is a computer environment, representative of a subset of the real world, and where models of the real world entities, process and events are included in a virtual (three-dimensional) space. Virtual environments are ideal tools for simulation of certain critical processes, such as radiological accidents, where human beings or properties can suffer irreversible or long term damages. Radiological accidents are characterized by the significant exposure to radiation of specialized workers and general public. The early detection of a radiological accident and the determination of its possible extension are essential factors for the planning of prompt answers and emergency actions. This paper proposes the integration of georeferenced representation of the three-dimensional space and agent-based models, with the objective to construct virtual environments that have the capacity to simulate radiological accidents. The three-dimensional georeferenced representations of space candidates are: 1) the spatial representation of traditional geographical information systems (GIS); 2) the representation adopted by Google Maps®. Adding agents to these spatial representations allow us to simulate radiological accidents, quantify the doses received by members of the public, obtain a possible spatial distribution of people contaminated, estimate the number of contaminated individuals, estimate the impact on the health-network, estimate environmental impacts, generate exclusion zones, build alternative scenarios and train staff to deal with radiological accidents. (author)

An Internet of Things based physiological signal monitoring and receiving system for virtual enhanced health care network.

Science.gov (United States)

Rajan, J Pandia; Rajan, S Edward

2018-01-01

Wireless physiological signal monitoring system designing with secured data communication in the health care system is an important and dynamic process. We propose a signal monitoring system using NI myRIO connected with the wireless body sensor network through multi-channel signal acquisition method. Based on the server side validation of the signal, the data connected to the local server is updated in the cloud. The Internet of Things (IoT) architecture is used to get the mobility and fast access of patient data to healthcare service providers. This research work proposes a novel architecture for wireless physiological signal monitoring system using ubiquitous healthcare services by virtual Internet of Things. We showed an improvement in method of access and real time dynamic monitoring of physiological signal of this remote monitoring system using virtual Internet of thing approach. This remote monitoring and access system is evaluated in conventional value. This proposed system is envisioned to modern smart health care system by high utility and user friendly in clinical applications. We claim that the proposed scheme significantly improves the accuracy of the remote monitoring system compared to the other wireless communication methods in clinical system.

Structure functions of longitudinal virtual photons at low virtualities

International Nuclear Information System (INIS)

Ioffe, B.L.; Shushpanov, I.A.

1996-01-01

The structure functions F L 1 and F L 2 of longitudinal virtual photons at low virtualities are calculated in the framework of chiral perturbation theory (ChPT) in the zero and first order of ChPT. It is assumed that the virtuality of a target longitudinal photon p 2 is much less than the virtuality of the hard projectile photon Q 2 and both are less than the characteristic ChPT scale. In this approximation the structure functions are determined by the production of two pions in γγ collisions. The numerical results for F L 2 and F L 1 are presented (the upper index refers to the longitudinal polarization of the virtual target photon). The possibilities of measurements of these structure functions are briefly discussed. copyright 1996 The American Physical Society

Virtual hand: a 3D tactile interface to virtual environments

Science.gov (United States)

Rogowitz, Bernice E.; Borrel, Paul

2008-02-01

We introduce a novel system that allows users to experience the sensation of touch in a computer graphics environment. In this system, the user places his/her hand on an array of pins, which is moved about space on a 6 degree-of-freedom robot arm. The surface of the pins defines a surface in the virtual world. This "virtual hand" can move about the virtual world. When the virtual hand encounters an object in the virtual world, the heights of the pins are adjusted so that they represent the object's shape, surface, and texture. A control system integrates pin and robot arm motions to transmit information about objects in the computer graphics world to the user. It also allows the user to edit, change and move the virtual objects, shapes and textures. This system provides a general framework for touching, manipulating, and modifying objects in a 3-D computer graphics environment, which may be useful in a wide range of applications, including computer games, computer aided design systems, and immersive virtual worlds.

The combined use of virtual reality exposure in the treatment of agoraphobia.

Science.gov (United States)

Pitti, Carmen T; Peñate, Wenceslao; de la Fuente, Juan; Bethencourt, Juan M; Roca-Sánchez, María J; Acosta, Leopoldo; Villaverde, María L; Gracia, Ramón

2015-01-01

This study compares the differential efficacy of three groups of treatments for agoraphobia: paroxetine combined with cognitive-behavioral therapy, paroxetine combined with cognitive-behavioral therapy and virtual reality exposure, and a group with only paroxetine. 99 patients with agoraphobia were finally selected. Both combined treatment groups received 11 sessions of cognitive-behavioral therapy, and one of the groups was also exposed to 4 sessions of virtual reality treatment. Treatments were applied in individual sessions once a week for 3 months. The three treatment groups showed statistically significant improvements. In some measures, combined treatment groups showed greater improvements. The virtual reality exposure group showed greater improvement confronting phobic stimuli. Treatments combining psychopharmacological and psychological therapy showed greater efficacy. Although the use of new technologies led to greater improvement, treatment adherence problems still remain.

CT differentiation of periappendiceal inflammation with appendicitis and pelvic inflammatory disease in woman with right lower quadrant pain

International Nuclear Information System (INIS)

Wang, Hyun Hye; Kim, Mi Young; Kim, Jung Eun; Kim, Youn Jeong; Suh, Chang Hae

2006-01-01

We wanted to determine the usefulness of the computed tomography (CT) findings for making the diagnosis between periappendiceal inflammation (PAI) with appendicitis and pelvic inflammatory disease (PID) for the women presenting with right lower quadrant pain. We retrospectively analyzed the CT findings of 83 women with right lower quadrant pain: PAI in 36 and PID in 47 patients. We reviewed the CT images, including the appendiceal diameter and the enhancing wall thickening, the cecal thickening, the location of the appendix, thickening of the right anterior renal fascia, abscess, mesenteric fatty infiltration, ascites, heterogeneous uterine enhancement and paralytic ileus. Statistical analysis was performed by using the t-test for the diameter of appendix, and the x 2 test or Fisher's exact test for the CT findings. The mean diameter of the appendix was 11.0 ± 3.4 mm for the PAI subjects and it was 6.7 ± 2.0 mm for the PID subjects (ρ < 0.0001). Wall thickening of the appendix was more commonly detected in PAI (25 subjects, 69%) than in PID (15 subjects, 32%) (ρ = 0.0007). Thickening of the right anterior renal fascia was more commonly detected in PAI (18 subjects, 50%) than in PID (7 subjects, 15%). Cecal thickening, ascitis, heterogeneous uterine enhancement and paralytic ileus were not significantly different between PAI and PID. Abscess and mesenteric fatty infiltration were more frequently detected in the RLQ and in the abdomen or pelvic cavity in PAI and PID, respectively (ρ < 0.05). There was no significant difference in the distribution of ascites between the diseases. The CT findings of the appendiceal diameter, enhancing wall thickening and thickening of the right anterior renal fascia are useful for making the diagnosis of PAI. The abdominal and pelvic distributions of abscess and mesenteric fatty infiltration are highly suggestive findings of PID

Potential climate change effects on the habitat of antarctic krill in the weddell quadrant of the southern ocean.

Science.gov (United States)

Hill, Simeon L; Phillips, Tony; Atkinson, Angus

2013-01-01

Antarctic krill is a cold water species, an increasingly important fishery resource and a major prey item for many fish, birds and mammals in the Southern Ocean. The fishery and the summer foraging sites of many of these predators are concentrated between 0° and 90°W. Parts of this quadrant have experienced recent localised sea surface warming of up to 0.2°C per decade, and projections suggest that further widespread warming of 0.27° to 1.08°C will occur by the late 21(st) century. We assessed the potential influence of this projected warming on Antarctic krill habitat with a statistical model that links growth to temperature and chlorophyll concentration. The results divide the quadrant into two zones: a band around the Antarctic Circumpolar Current in which habitat quality is particularly vulnerable to warming, and a southern area which is relatively insensitive. Our analysis suggests that the direct effects of warming could reduce the area of growth habitat by up to 20%. The reduction in growth habitat within the range of predators, such as Antarctic fur seals, that forage from breeding sites on South Georgia could be up to 55%, and the habitat's ability to support Antarctic krill biomass production within this range could be reduced by up to 68%. Sensitivity analysis suggests that the effects of a 50% change in summer chlorophyll concentration could be more significant than the direct effects of warming. A reduction in primary production could lead to further habitat degradation but, even if chlorophyll increased by 50%, projected warming would still cause some degradation of the habitat accessible to predators. While there is considerable uncertainty in these projections, they suggest that future climate change could have a significant negative effect on Antarctic krill growth habitat and, consequently, on Southern Ocean biodiversity and ecosystem services.

The effect of virtual reality gaming on dynamic balance in older adults.

Science.gov (United States)

Rendon, Abel Angel; Lohman, Everett B; Thorpe, Donna; Johnson, Eric G; Medina, Ernie; Bradley, Bruce

2012-07-01

physical therapy interventions that increase functional strength and balance have been shown to reduce falls in older adults. this study compared a virtual reality group (VRG) and a control group (CG). randomised controlled 6-week intervention with pre- and post-test evaluations. outpatient geriatric orthopaedic and balance physical therapy clinic. forty participants were randomised into two groups. the VRG received three different Nintendo® Wii FIT balance interventions three times per week for 6 weeks and the CG received no intervention. compared with the CG, post-intervention measurements showed significant improvements for the VRG in the 8-foot Up & Go test [median decrease of 1.0 versus -0.2 s, (P=0.038) and the Activities-specific Balance Confidence Scale (6.9 versus 1.3%) (P=0.038)]. virtual reality gaming provides clinicians with a useful tool for improving dynamic balance and balance confidence in older adults.

Advanced server virtualization VMware and Microsoft platforms in the virtual data center

CERN Document Server

Marshall, David; McCrory, Dave

2006-01-01

Executives of IT organizations are compelled to quickly implement server virtualization solutions because of significant cost savings. However, most IT professionals tasked with deploying virtualization solutions have little or no experience with the technology. This creates a high demand for information on virtualization and how to properly implement it in a datacenter. Advanced Server Virtualization: VMware® and Microsoft® Platforms in the Virtual Data Center focuses on the core knowledge needed to evaluate, implement, and maintain an environment that is using server virtualization. This boo

An innovative training program based on virtual reality and treadmill: effects on gait of persons with multiple sclerosis.

Science.gov (United States)

Peruzzi, Agnese; Zarbo, Ignazio Roberto; Cereatti, Andrea; Della Croce, Ugo; Mirelman, Anat

2017-07-01

In this single blind randomized controlled trial, we examined the effect of a virtual reality-based training on gait of people with multiple sclerosis. Twenty-five individuals with multiple sclerosis with mild to moderate disability were randomly assigned to either the control group (n = 11) or the experimental group (n = 14). The subjects in the control group received treadmill training. Subjects in the experimental group received virtual reality based treadmill training. Clinical measures and gait parameters were evaluated. Subjects in both the groups significantly improved the walking endurance and speed, cadence and stride length, lower limb joint ranges of motion and powers, during single and dual task gait. Moreover, subjects in the experimental group also improved balance, as indicated by the results of the clinical motor tests (p virtual reality to improve gait measures in individuals with multiple sclerosis. Implication of rehabilitation Gait deficits are common in multiple sclerosis (85%) and worsen during dual task activities. Intensive and progressive treadmill training, with and without virtual reality, is effective on dual task gait in persons with multiple sclerosis. Virtual reality-based treadmill training requiring obstacle negotiation increases the range of motion and the power generated at the hip, consequently allowing longer stride length and, consequently, higher gait speed.

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...... model for virtual classes has been a long-standing open question. This paper presents a virtual class calculus, vc, that captures the essence of virtual classes in these full-fledged programming languages. The key contributions of the paper are a formalization of the dynamic and static semantics of vc...

The Virtual Tablet: Virtual Reality as a Control System

Science.gov (United States)

Chronister, Andrew

2016-01-01

In the field of human-computer interaction, Augmented Reality (AR) and Virtual Reality (VR) have been rapidly growing areas of interest and concerted development effort thanks to both private and public research. At NASA, a number of groups have explored the possibilities afforded by AR and VR technology, among which is the IT Advanced Concepts Lab (ITACL). Within ITACL, the AVR (Augmented/Virtual Reality) Lab focuses on VR technology specifically for its use in command and control. Previous work in the AVR lab includes the Natural User Interface (NUI) project and the Virtual Control Panel (VCP) project, which created virtual three-dimensional interfaces that users could interact with while wearing a VR headset thanks to body- and hand-tracking technology. The Virtual Tablet (VT) project attempts to improve on these previous efforts by incorporating a physical surrogate which is mirrored in the virtual environment, mitigating issues with difficulty of visually determining the interface location and lack of tactile feedback discovered in the development of previous efforts. The physical surrogate takes the form of a handheld sheet of acrylic glass with several infrared-range reflective markers and a sensor package attached. Using the sensor package to track orientation and a motion-capture system to track the marker positions, a model of the surrogate is placed in the virtual environment at a position which corresponds with the real-world location relative to the user's VR Head Mounted Display (HMD). A set of control mechanisms is then projected onto the surface of the surrogate such that to the user, immersed in VR, the control interface appears to be attached to the object they are holding. The VT project was taken from an early stage where the sensor package, motion-capture system, and physical surrogate had been constructed or tested individually but not yet combined or incorporated into the virtual environment. My contribution was to combine the pieces of

Synthetic CO, H2 and H I surveys of the second galactic quadrant, and the properties of molecular gas

Science.gov (United States)

Duarte-Cabral, A.; Acreman, D. M.; Dobbs, C. L.; Mottram, J. C.; Gibson, S. J.; Brunt, C. M.; Douglas, K. A.

2015-03-01

We present CO, H2, H I and HISA (H I self-absorption) distributions from a set of simulations of grand design spirals including stellar feedback, self-gravity, heating and cooling. We replicate the emission of the second galactic quadrant by placing the observer inside the modelled galaxies and post-process the simulations using a radiative transfer code, so as to create synthetic observations. We compare the synthetic data cubes to observations of the second quadrant of the Milky Way to test the ability of the current models to reproduce the basic chemistry of the Galactic interstellar medium (ISM), as well as to test how sensitive such galaxy models are to different recipes of chemistry and/or feedback. We find that models which include feedback and self-gravity can reproduce the production of CO with respect to H2 as observed in our Galaxy, as well as the distribution of the material perpendicular to the Galactic plane. While changes in the chemistry/feedback recipes do not have a huge impact on the statistical properties of the chemistry in the simulated galaxies, we find that the inclusion of both feedback and self-gravity are crucial ingredients, as our test without feedback failed to reproduce all of the observables. Finally, even though the transition from H2 to CO seems to be robust, we find that all models seem to underproduce molecular gas, and have a lower molecular to atomic gas fraction than is observed. Nevertheless, our fiducial model with feedback and self-gravity has shown to be robust in reproducing the statistical properties of the basic molecular gas components of the ISM in our Galaxy.

Proposal for the award of a contract for the supply of four-quadrant switched-mode power converters rated at ± 120, ± 10V for the LHC

CERN Document Server

2003-01-01

This document concerns the award of a contract for the supply of power converters rated at ±120A, ±10V for the LHC. Following a market survey carried out among 147 firms in nineteen Member States, a call for tenders (IT-3037/AB/LHC) was sent on 5 May 2003 to 10 firms and three consortia, each consisting of two firms, in nine Member States. By the closing date, CERN had received nine tenders from nine firms in seven Member States. The Finance Committee is invited to agree to the negotiation of a contract with EFACEC (PT), the lowest conforming bidder after realignment, for the supply of 339 four-quadrant switched-mode power modules and 110 racks for a total amount of 1 652 128 euros (2 534 894 Swiss francs), not subject to revision, with an option for the supply of additional power modules and racks, for a total amount of 142 846 euros (219 171 Swiss francs), subject to revision for inflation from 1 January 2006, bringing the total amount to a maximum of 1 794 974 euros (2 754 065 Swiss francs). The rate of ...

Virtual projects

DEFF Research Database (Denmark)

Svejvig, Per; Commisso, Trine Hald

2012-01-01

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....... The overall implications for research and practice are to acknowledge virtual project management as very different to traditional project management and to address this difference.......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...

Virtual reality intervention for older women with breast cancer.

Science.gov (United States)

Schneider, Susan M; Ellis, Mathew; Coombs, William T; Shonkwiler, Erin L; Folsom, Linda C

2003-06-01

This study examined the effects of a virtual reality distraction intervention on chemotherapy-related symptom distress levels in 16 women aged 50 and older. A cross-over design was used to answer the following research questions: (1) Is virtual reality an effective distraction intervention for reducing chemotherapy-related symptom distress levels in older women with breast cancer? (2) Does virtual reality have a lasting effect? Chemotherapy treatments are intensive and difficult to endure. One way to cope with chemotherapy-related symptom distress is through the use of distraction. For this study, a head-mounted display (Sony PC Glasstron PLM - S700) was used to display encompassing images and block competing stimuli during chemotherapy infusions. The Symptom Distress Scale (SDS), Revised Piper Fatigue Scale (PFS), and the State Anxiety Inventory (SAI) were used to measure symptom distress. For two matched chemotherapy treatments, one pre-test and two post-test measures were employed. Participants were randomly assigned to receive the VR distraction intervention during one chemotherapy treatment and received no distraction intervention (control condition) during an alternate chemotherapy treatment. Analysis using paired t-tests demonstrated a significant decrease in the SAI (p = 0.10) scores immediately following chemotherapy treatments when participants used VR. No significant changes were found in SDS or PFS values. There was a consistent trend toward improved symptoms on all measures 48 h following completion of chemotherapy. Evaluation of the intervention indicated that women thought the head mounted device was easy to use, they experienced no cybersickness, and 100% would use VR again.

Decoupled Power Solution for Dual-input Isolated DC-DC Converters Using Four Quadrants Integrated Transformers (FQIT)

DEFF Research Database (Denmark)

Ouyang, Ziwei; Andersen, Michael A. E.; Thomsen, Ole Cornelius

2012-01-01

) space orthogonal flux is proposed in this paper. And thus a new geometry core and relative winding arrangements are proposed in accordance with the rthogonal flux decoupling technology. Due to the four secondary windings are arranged in a quadratic pattern at the base core plate with the two...... perpendicular primary windings, a name of “four quadrants integrated transformers” (FQIT) is therefore given to the proposed construction. Since the two primary windings are uncoupled, the FQIT allows the two input power stages to transfer the energy into the output load simultaneously or at any...... timemultiplexing scheme, which can optimize the utilization of diversified power energy sources, simplify the system structure, improve the flexibility and reduce the overall cost, so they are attractive for the hybrid renewable power system. Section IV initiates a discussion for the advantages of the FQIT...

Downhole seismic monitoring with Virtual Sources

Science.gov (United States)

Bakulin, A.; Calvert, R.

2005-12-01

sources and receivers (e.g. in-situ 4D seismic), but for now VSM may be the most economical alternative. By performing data-driven redatuming with measured Green's functions, these data can be recast into complete downhole dataset with buried Virtual Sources located at each downhole geophone. This step can be effectively thought of as a time reversal and it's remarkable feature is that velocity model between sources and receivers is not required to perform it. We will show various applications of the VSM method to several synthetic and real time-lapse datasets to illustrate the following advantages: 1) ability of VSM to eliminate overburden distortions without knowing velocity model between surface sources and downhole receivers, 2) greater quality of Virtual Sources in strongly scattering environment, 3) beneficial downward only radiation pattern on the Virtual Sources, 4) ability to correct non-repeatability caused by slight changes in acquisition geometry and temporal changes in the near surface, 5) ability to create P-wave Virtual Sources without shear radiation and S-sources without P-waves. Versatility of VSM to handle 1D, 2D and 3D situations and its ability to handle overburdens of any complexity makes it an indispensable tool for the active geophysical monitoring in a challenging geological environments. Although examples presented all come from an oilfield, it is straightforward to envision analogous applications in many other fields ranging from global geophysics to monitoring man-made structures.

Virtual versus real water transfers within China

Science.gov (United States)

Ma, Jing; Hoekstra, Arjen Y; Wang, Hao; Chapagain, Ashok K; Wang, Dangxian

2005-01-01

North China faces severe water scarcity—more than 40% of the annual renewable water resources are abstracted for human use. Nevertheless, nearly 10% of the water used in agriculture is employed in producing food exported to south China. To compensate for this ‘virtual water flow’ and to reduce water scarcity in the north, the huge south–north Water Transfer Project is currently being implemented. This paradox—the transfer of huge volumes of water from the water-rich south to the water-poor north versus transfer of substantial volumes of food from the food-sufficient north to the food-deficit south—is receiving increased attention, but the research in this field has not yet reached further than rough estimation and qualitative description. The aim of this paper is to review and quantify the volumes of virtual water flows between the regions in China and to put them in the context of water availability per region. The analysis shows that north China annually exports about 52 billion m3 of water in virtual form to south China, which is more than the maximum proposed water transfer volume along the three routes of the Water Transfer Project from south to north. PMID:16767828

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...... studied. The research question investigated is how collaboration is negotiated within virtual teams? This paper presents findings concerning how collaboration is negotiated within a virtual team and elaborate the difficulties due to invisible articulation work and managing multiple communities...... in transforming the virtual team into a community. It is argued that translucence in communication structures within the virtual team and between team and management is essential for engaging in a positive transformation process of trustworthiness supporting the team becoming a community, managing the immanent...

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 o...... 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....

Virtual water: Virtuous impact? : the unsteady state of virtual water

NARCIS (Netherlands)

Roth, D.; Warner, J.F.

2008-01-01

“Virtual water,” water needed for crop production, is now being mainstreamed in the water policy world. Relying on virtual water in the form of food imports is increasingly recommended as good policy for water-scarce areas. Virtual water globalizes discussions on water scarcity, ecological

Virtual water trade: an assessment of water use efficiency in the international food trade

Directory of Open Access Journals (Sweden)

H. Yang

2006-01-01

Full Text Available Amid an increasing water scarcity in many parts of the world, virtual water trade as both a policy instrument and practical means to balance the local, national and global water budget has received much attention in recent years. Building upon the knowledge of virtual water accounting in the literature, this study assesses the efficiency of water use embodied in the international food trade from the perspectives of exporting and importing countries and at the global and country levels. The investigation reveals that the virtual water flows primarily from countries of high crop water productivity to countries of low crop water productivity, generating a global saving in water use. Meanwhile, the total virtual water trade is dominated by green virtual water, which constitutes a low opportunity cost of water use as opposed to blue virtual water. A sensitivity analysis, however, suggests high uncertainties in the virtual water accounting and the estimation of the scale of water saving. The study also raises awareness of the limited effect of water scarcity on the global virtual water trade and the negative implications of the global water saving for the water use efficiency and food security in importing countries and the environment in exporting countries. The analysis shows the complexity in evaluating the efficiency gains in the international virtual water trade. The findings of the study, nevertheless, call for a greater emphasis on rainfed agriculture to improve the global food security and environmental sustainability.

Training multitasking in a virtual supermarket: a novel intervention after stroke.

Science.gov (United States)

Rand, Debbie; Weiss, Patrice L Tamar; Katz, Noomi

2009-01-01

To explore the potential of the VMall, a virtual supermarket running on a video-capture virtual reality system, as an intervention tool for people who have multitasking deficits after stroke. Poststroke, 4 participants received ten 60-min sessions over 3 weeks using the VMall. The intervention focused on improving multitasking while the participant was engaged in a virtual shopping task. Instruments included the Multiple Errands Test-Hospital Version (MET-HV) in a real mall and in the VMall. Participants achieved improvements ranging from 20.5% to 51.2% for most of the MET-HV measures performed in a real shopping mall and in the VMall. The data support the VMall's potential as a motivating and effective intervention tool for the rehabilitation of people poststroke who have multitasking deficits during the performance of daily tasks. However, because the sample was small, additional intervention studies with the VMall should be conducted.

Evolution-based Virtual Content Insertion with Visually Virtual Interactions in Videos

Science.gov (United States)

Chang, Chia-Hu; Wu, Ja-Ling

With the development of content-based multimedia analysis, virtual content insertion has been widely used and studied for video enrichment and multimedia advertising. However, how to automatically insert a user-selected virtual content into personal videos in a less-intrusive manner, with an attractive representation, is a challenging problem. In this chapter, we present an evolution-based virtual content insertion system which can insert virtual contents into videos with evolved animations according to predefined behaviors emulating the characteristics of evolutionary biology. The videos are considered not only as carriers of message conveyed by the virtual content but also as the environment in which the lifelike virtual contents live. Thus, the inserted virtual content will be affected by the videos to trigger a series of artificial evolutions and evolve its appearances and behaviors while interacting with video contents. By inserting virtual contents into videos through the system, users can easily create entertaining storylines and turn their personal videos into visually appealing ones. In addition, it would bring a new opportunity to increase the advertising revenue for video assets of the media industry and online video-sharing websites.

Theft of Virtual Property — Towards Security Requirements for Virtual Worlds

Science.gov (United States)

Beyer, Anja

The article is focused to introduce the topic of information technology security for Virtual Worlds to a security experts’ audience. Virtual Worlds are Web 2.0 applications where the users cruise through the world with their individually shaped avatars to find either amusement, challenges or the next best business deal. People do invest a lot of time but beyond they invest in buying virtual assets like fantasy witcheries, wepaons, armour, houses, clothes,...etc with the power of real world money. Although it is called “virtual” (which is often put on the same level as “not existent”) there is a real value behind it. In November 2007 dutch police arrested a seventeen years old teenager who was suspicted to have stolen virtual items in a Virtual World called Habbo Hotel [Reuters07]. In order to successfully provide security mechanisms into Virtual Worlds it is necessarry to fully understand the domain for which the security mechansims are defined. As Virtual Worlds must be clasified into the domain of Social Software the article starts with an overview of how to understand Web 2.0 and gives a short introduction to Virtual Worlds. The article then provides a consideration of assets of Virtual Worlds participants, describes how these assets can be threatened and gives an overview of appopriate security requirements and completes with an outlook of possible countermeasures.

Interaction with virtual crowd in Immersive and semi‐Immersive Virtual Reality systems

OpenAIRE

Kyriakou, Marios; Pan, Xueni; Chrysanthou, Yiorgos

2016-01-01

This study examines attributes of virtual human behavior that may increase the plausibility of a simulated crowd and affect the user's experience in Virtual Reality. Purpose-developed experiments in both Immersive and semi-Immersive Virtual Reality systems queried the impact of collision and basic interaction between real-users and the virtual crowd and their effect on the apparent realism and ease of navigation within Virtual Reality (VR). Participants' behavior and subjective measurements i...

Designing Virtual Worlds

DEFF Research Database (Denmark)

Gürsimsek, Remzi Ates

2014-01-01

The online social platforms known as virtual worlds present their users various affordances for avatar based co-presence, social interaction and provide tools for collaborative content creation, including objects, textures and animations. The users of these worlds navigate their avatars as personal...... the audio-visual characteristics of designing in multi-user virtual environments generate experiential, interpersonal and textual meaning potentials....... mediators in 3D virtual space to collaborate and co-design the digital content. These co-designers are also the residents of these worlds, as they socialize by building inworld friendships. This article presents a social semiotic analysis of the three-dimensional virtual places and artifacts in the virtual...

A novel method for direct localized sound speed measurement using the virtual source paradigm

DEFF Research Database (Denmark)

Byram, Brett; Trahey, Gregg E.; Jensen, Jørgen Arendt

2007-01-01

) mediums. The inhomogeneous mediums were arranged as an oil layer, one 6 mm thick and the other 11 mm thick, on top of a water layer. To complement the phantom studies, sources of error for spatial registration of virtual detectors were simulated. The sources of error presented here are multiple sound...... registered virtual detector. Between a pair of registered virtual detectors a spherical wave is propagated. By beamforming the received data the time of flight between the two virtual sources can be calculated. From this information the local sound speed can be estimated. Validation of the estimator used...... both phantom and simulation results. The phantom consisted of two wire targets located near the transducer's axis at depths of 17 and 28 mm. Using this phantom the sound speed between the wires was measured for a homogeneous (water) medium and for two inhomogeneous (DB-grade castor oil and water...

Server virtualization solutions

OpenAIRE

Jonasts, Gusts

2012-01-01

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...

Virtual Trackballs Revisited

OpenAIRE

Henriksen, Knud; Sporring, Jon; Hornbæk, Kasper

2004-01-01

Udgivelsesdato: March/April 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 SENTENC...

Interactive Virtual Cinematography

OpenAIRE

Burelli, Paolo

2012-01-01

A virtual camera represents the point-of-view of the player through which sheperceives the game world and gets feedback on her actions. Thus, the virtualcamera plays a vital role in 3D computer games and aects player experienceand enjoyability in games. Interactive virtual cinematography is the process ofvisualising the content of a virtual environment by positioning and animatingthe virtual camera in the context of interactive applications such as a computergame.Camera placement and animatio...

Using a virtual reality in the inference based treatment of compulsive hoarding

Directory of Open Access Journals (Sweden)

Marie-Eve St-Pierre-Delorme

2016-07-01

Full Text Available The present study evaluated the efficacy of adding a virtual reality (VR component to the treatment of compulsive hoarding (CH following inference based therapy. Participants were randomly assigned to either an experimental or a control condition. Seven participants received the experimental and seven received the control condition. Five sessions of one hour were administered weekly. A significant difference indicated that the level of clutter in the bedroom tended to diminish more in the experimental group as compared to the control group F(2,24 = 2.28, p = .10. In addition, the results demonstrated that both groups were immersed and present in the environment. The results on post-treatment measures of CH (Saving Inventory revised, Saving Cognition Inventory and Clutter Image Rating scale demonstrate the efficacy of inference based therapy in terms of symptom reduction. Overall, these results suggest that the creation of a virtual environment may be effective in the treatment of CH by helping the compulsive hoarders take action over they're clutter.

Virtual Reflexes

OpenAIRE

Jonker, Catholijn; Broekens, Joost; Plaat, Aske

2014-01-01

Virtual Reality is used successfully to treat people for regular phobias. A new challenge is to develop Virtual Reality Exposure Training for social skills. Virtual actors in such systems have to show appropriate social behavior including emotions, gaze, and keeping distance. The behavior must be realistic and real-time. Current approaches consist of four steps: 1) trainee social signal detection, 2) cognitive-affective interpretation, 3) determination of the appropriate bodily responses, and...

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

number of randomised controlled trials, the evidence remains mostly low quality when rated using the GRADE system. Control groups usually received no intervention or therapy based on a standard-care approach. results were not statistically significant for upper limb function (standardised mean difference (SMD) 0.07, 95% confidence intervals (CI) -0.05 to 0.20, 22 studies, 1038 participants, low-quality evidence) when comparing virtual reality to conventional therapy. However, when virtual reality was used in addition to usual care (providing a higher dose of therapy for those in the intervention group) there was a statistically significant difference between groups (SMD 0.49, 0.21 to 0.77, 10 studies, 210 participants, low-quality evidence). when compared to conventional therapy approaches there were no statistically significant effects for gait speed or balance. Results were statistically significant for the activities of daily living (ADL) outcome (SMD 0.25, 95% CI 0.06 to 0.43, 10 studies, 466 participants, moderate-quality evidence); however, we were unable to pool results for cognitive function, participation restriction, or quality of life. Twenty-three studies reported that they monitored for adverse events; across these studies there were few adverse events and those reported were relatively mild. We found evidence that the use of virtual reality and interactive video gaming was not more beneficial than conventional therapy approaches in improving upper limb function. Virtual reality may be beneficial in improving upper limb function and activities of daily living function when used as an adjunct to usual care (to increase overall therapy time). There was insufficient evidence to reach conclusions about the effect of virtual reality and interactive video gaming on gait speed, balance, participation, or quality of life. This review found that time since onset of stroke, severity of impairment, and the type of device (commercial or customised) were not strong

Virtual Bystanders in a Language Lesson: Examining the Effect of Social Evaluation, Vicarious Experience, Cognitive Consistency and Praising on Students' Beliefs, Self-Efficacy and Anxiety in a Virtual Reality Environment

Science.gov (United States)

Qu, Chao; Ling, Yun; Heynderickx, Ingrid; Brinkman, Willem-Paul

2015-01-01

Bystanders in a real world's social setting have the ability to influence people’s beliefs and behavior. This study examines whether this effect can be recreated in a virtual environment, by exposing people to virtual bystanders in a classroom setting. Participants (n = 26) first witnessed virtual students answering questions from an English teacher, after which they were also asked to answer questions from the teacher as part of a simulated training for spoken English. During the experiment the attitudes of the other virtual students in the classroom was manipulated; they could whisper either positive or negative remarks to each other when a virtual student was talking or when a participant was talking. The results show that the expressed attitude of virtual bystanders towards the participants affected their self-efficacy, and their avoidance behavior. Furthermore, the experience of witnessing bystanders commenting negatively on the performance of other students raised the participants’ heart rate when it was their turn to speak. Two-way interaction effects were also found on self-reported anxiety and self-efficacy. After witnessing bystanders’ positive attitude towards peer students, participants’ self-efficacy when answering questions received a boost when bystanders were also positive towards them, and a blow when bystanders reversed their attitude by being negative towards them. Still, inconsistency, instead of consistency, between the bystanders’ attitudes towards virtual peers and the participants was not found to result in a larger change in the participants’ beliefs. Finally the results also reveal that virtual flattering or destructive criticizing affected the participants’ beliefs not only about the virtual bystanders, but also about the neutral teacher. Together these findings show that virtual bystanders in a classroom can affect people’s beliefs, anxiety and behavior. PMID:25884211

Virtual bystanders in a language lesson: examining the effect of social evaluation, vicarious experience, cognitive consistency and praising on students' beliefs, self-efficacy and anxiety in a virtual reality environment.

Science.gov (United States)

Qu, Chao; Ling, Yun; Heynderickx, Ingrid; Brinkman, Willem-Paul

2015-01-01

Bystanders in a real world's social setting have the ability to influence people's beliefs and behavior. This study examines whether this effect can be recreated in a virtual environment, by exposing people to virtual bystanders in a classroom setting. Participants (n = 26) first witnessed virtual students answering questions from an English teacher, after which they were also asked to answer questions from the teacher as part of a simulated training for spoken English. During the experiment the attitudes of the other virtual students in the classroom was manipulated; they could whisper either positive or negative remarks to each other when a virtual student was talking or when a participant was talking. The results show that the expressed attitude of virtual bystanders towards the participants affected their self-efficacy, and their avoidance behavior. Furthermore, the experience of witnessing bystanders commenting negatively on the performance of other students raised the participants' heart rate when it was their turn to speak. Two-way interaction effects were also found on self-reported anxiety and self-efficacy. After witnessing bystanders' positive attitude towards peer students, participants' self-efficacy when answering questions received a boost when bystanders were also positive towards them, and a blow when bystanders reversed their attitude by being negative towards them. Still, inconsistency, instead of consistency, between the bystanders' attitudes towards virtual peers and the participants was not found to result in a larger change in the participants' beliefs. Finally the results also reveal that virtual flattering or destructive criticizing affected the participants' beliefs not only about the virtual bystanders, but also about the neutral teacher. Together these findings show that virtual bystanders in a classroom can affect people's beliefs, anxiety and behavior.

Virtual bystanders in a language lesson: examining the effect of social evaluation, vicarious experience, cognitive consistency and praising on students' beliefs, self-efficacy and anxiety in a virtual reality environment.

Directory of Open Access Journals (Sweden)

Chao Qu

Full Text Available Bystanders in a real world's social setting have the ability to influence people's beliefs and behavior. This study examines whether this effect can be recreated in a virtual environment, by exposing people to virtual bystanders in a classroom setting. Participants (n = 26 first witnessed virtual students answering questions from an English teacher, after which they were also asked to answer questions from the teacher as part of a simulated training for spoken English. During the experiment the attitudes of the other virtual students in the classroom was manipulated; they could whisper either positive or negative remarks to each other when a virtual student was talking or when a participant was talking. The results show that the expressed attitude of virtual bystanders towards the participants affected their self-efficacy, and their avoidance behavior. Furthermore, the experience of witnessing bystanders commenting negatively on the performance of other students raised the participants' heart rate when it was their turn to speak. Two-way interaction effects were also found on self-reported anxiety and self-efficacy. After witnessing bystanders' positive attitude towards peer students, participants' self-efficacy when answering questions received a boost when bystanders were also positive towards them, and a blow when bystanders reversed their attitude by being negative towards them. Still, inconsistency, instead of consistency, between the bystanders' attitudes towards virtual peers and the participants was not found to result in a larger change in the participants' beliefs. Finally the results also reveal that virtual flattering or destructive criticizing affected the participants' beliefs not only about the virtual bystanders, but also about the neutral teacher. Together these findings show that virtual bystanders in a classroom can affect people's beliefs, anxiety and behavior.

Virtual Globes, where we were, are and will be

Science.gov (United States)

Dehn, J.; Webley, P. W.; Worden, A. K.

2016-12-01

Ten years ago, Google Earth was new, and the first "Virtual Globes" session was held at AGU. Only a few of us realized the potential of this technology at the time, but the idea quickly caught on. At that time a virtual globe came in two flavors, first a complex GIS system that was utterly impenetrable for the public, or a more accessible version with limited functionality and layers that was available on a desktop computer with a good internet connection. Google Earth's use of the Keyhole Markup Language opened the door for scientists and the public to share data and visualizations across disciplines and revolutionized how everyone uses geographic data. In the following 10 years, KML became more advanced, virtual globes moved to mobile and handheld platforms, and the Google Earth engine allowed for more complex data sharing among scientists. Virtual globe images went from a rare commodity to being everywhere in our lives, from weather forecasts, in our cars, on our smart-phones and shape how we receive and process data. This is a fantastic tool for education and with newer technologies can reach the the remote corners of the world and developing countries. New and emerging technologies allow for augmented reality to be merged with the globes, and for real-time data integration with sensors built into mobile devices or add-ons. This presentation will follow the history of virtual globes in the geosciences, show how robust technologies can be used in the field and classroom today, and make some suggestions for the future.

Missing depth cues in virtual reality limit performance and quality of three dimensional reaching movements.

Science.gov (United States)

Gerig, Nicolas; Mayo, Johnathan; Baur, Kilian; Wittmann, Frieder; Riener, Robert; Wolf, Peter

2018-01-01

Goal-directed reaching for real-world objects by humans is enabled through visual depth cues. In virtual environments, the number and quality of available visual depth cues is limited, which may affect reaching performance and quality of reaching movements. We assessed three-dimensional reaching movements in five experimental groups each with ten healthy volunteers. Three groups used a two-dimensional computer screen and two groups used a head-mounted display. The first screen group received the typically recreated visual depth cues, such as aerial and linear perspective, occlusion, shadows, and texture gradients. The second screen group received an abstract minimal rendering lacking those. The third screen group received the cues of the first screen group and absolute depth cues enabled by retinal image size of a known object, which realized with visual renderings of the handheld device and a ghost handheld at the target location. The two head-mounted display groups received the same virtually recreated visual depth cues as the second or the third screen group respectively. Additionally, they could rely on stereopsis and motion parallax due to head-movements. All groups using the screen performed significantly worse than both groups using the head-mounted display in terms of completion time normalized by the straight-line distance to the target. Both groups using the head-mounted display achieved the optimal minimum in number of speed peaks and in hand path ratio, indicating that our subjects performed natural movements when using a head-mounted display. Virtually recreated visual depth cues had a minor impact on reaching performance. Only the screen group with rendered handhelds could outperform the other screen groups. Thus, if reaching performance in virtual environments is in the main scope of a study, we suggest applying a head-mounted display. Otherwise, when two-dimensional screens are used, achievable performance is likely limited by the reduced depth

A Virtual Reality Task Based on Animal Research - Spatial Learning and Memory in Patients after the First Episode of Schizophrenia

Directory of Open Access Journals (Sweden)

Iveta eFajnerova

2014-05-01

Full Text Available Objective: Cognitive deficit is considered to be a characteristic feature of schizophrenia disorder. A similar cognitive dysfunction was demonstrated in animal models of schizophrenia. However, the poor comparability of methods used to assess cognition in animals and humans could be responsible for low predictive validity of current animal models. In order to assess spatial abilities in schizophrenia and compare our results with the data obtained in animal models we designed a virtual analogue of the Morris water maze (MWM, the virtual Four Goals Navigation (vFGN task.Method: Twenty-nine patients after the first psychotic episode with schizophrenia symptoms and a matched group of healthy volunteers performed the vFGN task. They were required to find and remember four hidden goal positions in an enclosed virtual arena. The task consisted of two parts. The Reference memory (RM session with a stable goal position was designed to test spatial learning. The Delayed-matching-to-place (DMP session presented a modified working memory protocol designed to test the ability to remember a sequence of three hidden goal positions.Results: Data obtained in the RM session show impaired spatial learning in schizophrenia patients compared to healthy controls in pointing and navigation accuracy. The DMP session showed impaired spatial memory in schizophrenia during the recall of spatial sequence and similar deficit in spatial bias in probe trials. The pointing accuracy and the quadrant preference showed higher sensitivity toward the cognitive deficit than the navigation accuracy. Direct navigation to the goal was affected by sex and age of the tested subjects. Age affected spatial performance only in healthy controls. Conclusions: Despite some limitations of the study, our results correspond well to previous studies in animal models of schizophrenia and support the decline of spatial cognition in schizophrenia, indicating the usefulness of the vFGN task in

Virtual Singular Scattering of Electromagnetic Waves in Transformation Media Concept

Directory of Open Access Journals (Sweden)

M. Y. Barabanenkov

2012-07-01

Full Text Available If a scatterer and an observation point (receive both approach the so-called near field zone of a source of electromagnetic waves, the scattering process becomes singular one which is mathematically attributed to the spatial singularity of the free space Green function at the origin. Starting from less well known property of left-handed material slab to transfer the singularity of the free space Green function by implementing coordinate transformation, we present a phenomenon of virtual singular scattering of electromagnetic wave on an inhomogeneity located in the volume of left – handed material slab. Virtual singular scattering means that a scatterer is situated only virtually in the near field zone of a source, being, in fact, positioned in the far field zone. Such a situation is realized if a scatterer is embedded into a flat Veselago’s lens and approaches the lens’s inner focus because a slab of Veselago medium produces virtual sources inside and behind the slab and virtual scatterer (as a source of secondary waves from both slab sides. Considering a line-like dielectric scatterer we demonstrate that the scattering efficiency is proportional to product of singular quasistatic parts of two empty space Green functions that means a multiplicative quasistatic singularity of the Green function for a slab of inhomogeneous Veselago medium. We calculate a resonance value of the scattering amplitude in the regime similar to the known Mie resonance scattering.

[Virtual + 1] * Reality

Science.gov (United States)

Beckhaus, Steffi

Virtual Reality aims at creating an artificial environment that can be perceived as a substitute to a real setting. Much effort in research and development goes into the creation of virtual environments that in their majority are perceivable only by eyes and hands. The multisensory nature of our perception, however, allows and, arguably, also expects more than that. As long as we are not able to simulate and deliver a fully sensory believable virtual environment to a user, we could make use of the fully sensory, multi-modal nature of real objects to fill in for this deficiency. The idea is to purposefully integrate real artifacts into the application and interaction, instead of dismissing anything real as hindering the virtual experience. The term virtual reality - denoting the goal, not the technology - shifts from a core virtual reality to an “enriched” reality, technologically encompassing both the computer generated and the real, physical artifacts. Together, either simultaneously or in a hybrid way, real and virtual jointly provide stimuli that are perceived by users through their senses and are later formed into an experience by the user's mind.

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.

Tangible interfaces in virtual environments, case study: Instituto de Engenharia Nuclear Virtual

Energy Technology Data Exchange (ETDEWEB)

Santo, Andre Cotelli do E.; Mol, Antonio Carlos A.; Pinto, Emanuele Oliveira; Melo, Joao Victor da C.; Paula, Vanessa Marcia de; Freitas, Victor Goncalves Gloria [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Machado, Daniel Mol [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Instituto Alberto Luiz Coimbra

2015-07-01

Virtual Reality (VR) techniques allow the creation of realistic representations of an individual. These technologies are being applied in several fields such as training, simulations, virtual experiments and new applications are constantly being found. This work aims to present an interactive system in virtual environments without the use of peripherals typically found in computers such as mouse and keyboard. Through the movement of head and hands it is possible to control and navigate the virtual character (avatar) in a virtual environment, an improvement in the man-machine integration. The head movements are recognized using a virtual helmet with a tracking system. An infrared camera detects the position of infrared LEDs located in the operator's head and places the vision of the virtual character in accordance with the operator's vision. The avatar control is performed by a system that detects the movement of the hands, using infrared sensors, allowing the user to move it in the virtual environment. This interaction system was implemented in the virtual model of the Instituto de Engenharia Nuclear (IEN), which is located on the Ilha do Fundao - Rio de Janeiro - Brazil. This three-dimensional environment, in which avatars can move and interact according to the user movements, gives a feeling of realism to the operator. The results show an interface that allows a higher degree of immersion of the operator in the virtual environment, promoting a more engaging and dynamic way of working. (author)

Tangible interfaces in virtual environments, case study: Instituto de Engenharia Nuclear Virtual

International Nuclear Information System (INIS)

Santo, Andre Cotelli do E.; Mol, Antonio Carlos A.; Pinto, Emanuele Oliveira; Melo, Joao Victor da C.; Paula, Vanessa Marcia de; Freitas, Victor Goncalves Gloria; Machado, Daniel Mol

2015-01-01

Virtual Reality (VR) techniques allow the creation of realistic representations of an individual. These technologies are being applied in several fields such as training, simulations, virtual experiments and new applications are constantly being found. This work aims to present an interactive system in virtual environments without the use of peripherals typically found in computers such as mouse and keyboard. Through the movement of head and hands it is possible to control and navigate the virtual character (avatar) in a virtual environment, an improvement in the man-machine integration. The head movements are recognized using a virtual helmet with a tracking system. An infrared camera detects the position of infrared LEDs located in the operator's head and places the vision of the virtual character in accordance with the operator's vision. The avatar control is performed by a system that detects the movement of the hands, using infrared sensors, allowing the user to move it in the virtual environment. This interaction system was implemented in the virtual model of the Instituto de Engenharia Nuclear (IEN), which is located on the Ilha do Fundao - Rio de Janeiro - Brazil. This three-dimensional environment, in which avatars can move and interact according to the user movements, gives a feeling of realism to the operator. The results show an interface that allows a higher degree of immersion of the operator in the virtual environment, promoting a more engaging and dynamic way of working. (author)

Thermal State-of-Charge in Solar Heat Receivers

Science.gov (United States)

Hall, Carsie, A., III; Glakpe, Emmanuel K.; Cannon, Joseph N.; Kerslake, Thomas W.

1998-01-01

A theoretical framework is developed to determine the so-called thermal state-of-charge (SOC) in solar heat receivers employing encapsulated phase change materials (PCMS) that undergo cyclic melting and freezing. The present problem is relevant to space solar dynamic power systems that would typically operate in low-Earth-orbit (LEO). The solar heat receiver is integrated into a closed-cycle Brayton engine that produces electric power during sunlight and eclipse periods of the orbit cycle. The concepts of available power and virtual source temperature, both on a finite-time basis, are used as the basis for determining the SOC. Analytic expressions for the available power crossing the aperture plane of the receiver, available power stored in the receiver, and available power delivered to the working fluid are derived, all of which are related to the SOC through measurable parameters. Lower and upper bounds on the SOC are proposed in order to delineate absolute limiting cases for a range of input parameters (orbital, geometric, etc.). SOC characterization is also performed in the subcooled, two-phase, and superheat regimes. Finally, a previously-developed physical and numerical model of the solar heat receiver component of NASA Lewis Research Center's Ground Test Demonstration (GTD) system is used in order to predict the SOC as a function of measurable parameters.

A non-invasive modality: the US virtual touch tissue quantification (VTTQ) for evaluation of breast cancer.

Science.gov (United States)

Tamaki, Kentaro; Tamaki, Nobumitsu; Kamada, Yoshihiko; Uehara, Kano; Miyashita, Minoru; Ishida, Takanori; Sasano, Hironobu

2013-09-01

We evaluated the biologic features of breast tissues using a newly developed non-invasive diagnostic system, named virtual touch tissue quantification. A total of 180 patients including 115 invasive ductal carcinoma, 30 ductal carcinoma in situ, 4 mucinous carcinoma, 7 invasive lobular carcinoma, 8 fibroadenoma, 12 fibrocystic change and 4 intraductal papilloma were studied at Nahanishi Clinic, Okinawa. We first compared the results of virtual touch tissue quantification according to each histologic subtype and determined the optimal cutoff values for virtual touch tissue quantification to distinguish benign from malignant tissues, using the receiver operating characteristic method. In addition, we also examined the correlation between virtual touch tissue quantification velocities and Ki-67, estrogen receptor, progesterone receptor or human epidermal growth factor receptor 2 in cases of invasive ductal carcinoma using linear regression analyses and Student's t-test. Virtual touch tissue quantification velocities were statistically higher in malignant cases than in benign cases (P breast cancer pathology in a non-invasive fashion.

Virtual volatility

Science.gov (United States)

Silva, A. Christian; Prange, Richard E.

2007-03-01

We introduce the concept of virtual volatility. This simple but new measure shows how to quantify the uncertainty in the forecast of the drift component of a random walk. The virtual volatility also is a useful tool in understanding the stochastic process for a given portfolio. In particular, and as an example, we were able to identify mean reversion effect in our portfolio. Finally, we briefly discuss the potential practical effect of the virtual volatility on an investor asset allocation strategy.

Virtual laboratories : comparability of real and virtual environments for environmental psychology

NARCIS (Netherlands)

Kort, de Y.A.W.; IJsselsteijn, W.A.; Kooijman, J.M.A.; Schuurmans, Y.

2003-01-01

Virtual environments have the potential to become important new research tools in environment behavior research. They could even become the future (virtual) laboratories, if reactions of people to virtual environments are similar to those in real environments. The present study is an exploration of

National randomized controlled trial of virtual house calls for Parkinson disease.

Science.gov (United States)

Beck, Christopher A; Beran, Denise B; Biglan, Kevin M; Boyd, Cynthia M; Dorsey, E Ray; Schmidt, Peter N; Simone, Richard; Willis, Allison W; Galifianakis, Nicholas B; Katz, Maya; Tanner, Caroline M; Dodenhoff, Kristen; Aldred, Jason; Carter, Julie; Fraser, Andrew; Jimenez-Shahed, Joohi; Hunter, Christine; Spindler, Meredith; Reichwein, Suzanne; Mari, Zoltan; Dunlop, Becky; Morgan, John C; McLane, Dedi; Hickey, Patrick; Gauger, Lisa; Richard, Irene Hegeman; Mejia, Nicte I; Bwala, Grace; Nance, Martha; Shih, Ludy C; Singer, Carlos; Vargas-Parra, Silvia; Zadikoff, Cindy; Okon, Natalia; Feigin, Andrew; Ayan, Jean; Vaughan, Christina; Pahwa, Rajesh; Dhall, Rohit; Hassan, Anhar; DeMello, Steven; Riggare, Sara S; Wicks, Paul; Achey, Meredith A; Elson, Molly J; Goldenthal, Steven; Keenan, H Tait; Korn, Ryan; Schwarz, Heidi; Sharma, Saloni; Stevenson, E Anna; Zhu, William

2017-09-12

To determine whether providing remote neurologic care into the homes of people with Parkinson disease (PD) is feasible, beneficial, and valuable. In a 1-year randomized controlled trial, we compared usual care to usual care supplemented by 4 virtual visits via video conferencing from a remote specialist into patients' homes. Primary outcome measures were feasibility, as measured by the proportion who completed at least one virtual visit and the proportion of virtual visits completed on time; and efficacy, as measured by the change in the Parkinson's Disease Questionnaire-39, a quality of life scale. Secondary outcomes included quality of care, caregiver burden, and time and travel savings. A total of 927 individuals indicated interest, 210 were enrolled, and 195 were randomized. Participants had recently seen a specialist (73%) and were largely college-educated (73%) and white (96%). Ninety-five (98% of the intervention group) completed at least one virtual visit, and 91% of 388 virtual visits were completed. Quality of life did not improve in those receiving virtual house calls (0.3 points worse on a 100-point scale; 95% confidence interval [CI] -2.0 to 2.7 points; p = 0.78) nor did quality of care or caregiver burden. Each virtual house call saved patients a median of 88 minutes (95% CI 70-120; p < 0.0001) and 38 miles per visit (95% CI 36-56; p < 0.0001). Providing remote neurologic care directly into the homes of people with PD was feasible and was neither more nor less efficacious than usual in-person care. Virtual house calls generated great interest and provided substantial convenience. NCT02038959. This study provides Class III evidence that for patients with PD, virtual house calls from a neurologist are feasible and do not significantly change quality of life compared to in-person visits. The study is rated Class III because it was not possible to mask patients to visit type. © 2017 American Academy of Neurology.

The relationship between sitting posture and seated-related upper quadrant musculoskeletal pain in computing South African adolescents: A prospective study.

Science.gov (United States)

Brink, Yolandi; Louw, Quinette; Grimmer, Karen; Jordaan, Esmè

2015-12-01

There is evidence that consistent sitting for prolonged periods is associated with upper quadrant musculoskeletal pain (UQMP). It is unclear whether postural alignment is a significant risk factor. The aim of the prospective study (2010-2011) was to ascertain if three-dimensional sitting postural angles, measured in a real-life school computer classroom setting, predict seated-related UQMP. Asymptomatic Grade 10 high-school students, aged 15-17 years, undertaking Computer Application Technology, were eligible to participate. Using the 3D Posture Analysis Tool, sitting posture was measured while students used desk-top computers. Posture was reported as five upper quadrant angles (Head flexion, Neck flexion; Craniocervical angle, Trunk flexion and Head lateral bending). The Computer Usage Questionnaire measured seated-related UQMP and hours of computer use. The Beck Depression Inventory and the Multidimensional Anxiety Scale for Children assessed psychosocial factors. Sitting posture, computer use and psychosocial factors were measured at baseline. UQMP was measured at six months and one-year follow-up. 211, 190 and 153 students participated at baseline, six months and one-year follow-up respectively. 34.2% students complained of seated-related UQMP during the follow-up period. Increased head flexion (HF) predicted seated-related UQMP developing over time for a small group of students with pain scores greater than the 90th pain percentile, adjusted for age, gender, BMI, computer use and psychosocial factors (p = 0.003). The pain score increased 0.22 points per 1° increase in HF. Classroom ergonomics and postural hygiene should therefore focus on reducing large HF angles among computing adolescents. Copyright © 2015 Elsevier Ltd. All rights reserved.

High availability using virtualization

International Nuclear Information System (INIS)

Calzolari, Federico; Arezzini, Silvia; Ciampa, Alberto; Mazzoni, Enrico; Domenici, Andrea; Vaglini, Gigliola

2010-01-01

High availability has always been one of the main problems for a data center. Till now high availability was achieved by host per host redundancy, a highly expensive method in terms of hardware and human costs. A new approach to the problem can be offered by virtualization. Using virtualization, it is possible to achieve a redundancy system for all the services running on a data center. This new approach to high availability allows the running virtual machines to be distributed over a small number of servers, by exploiting the features of the virtualization layer: start, stop and move virtual machines between physical hosts. The 3RC system is based on a finite state machine, providing the possibility to restart each virtual machine over any physical host, or reinstall it from scratch. A complete infrastructure has been developed to install operating system and middleware in a few minutes. To virtualize the main servers of a data center, a new procedure has been developed to migrate physical to virtual hosts. The whole Grid data center SNS-PISA is running at the moment in virtual environment under the high availability system.

Virtual reality in education

OpenAIRE

Minocha, Shailey; Tudor, Ana-Despina

2017-01-01

In this workshop-presentation, we described the evolution of virtual reality technologies and our research from 3D virtual worlds, 3D virtual environments built in gaming environments such as Unity 3D, 360-degree videos, and mobile virtual reality via Google Expeditions. For each of these four technologies, we discussed the affordances of the technologies and how they contribute towards learning and teaching. We outlined the significance of students being aware of the different virtual realit...

Virtual Reality: Principles and Applications

OpenAIRE

MÉRIENNE , Frédéric

2017-01-01

Virtual reality aims at immersing a user in a virtual environment. Dedicated virtual reality technologies of human–computer interaction enable to make the link between the user and a virtual environment in capturing the user’s motion, acting on his senses as well as computing the virtual experience in real-time. The immersion in virtual environment is evaluated through the user’s perception and reaction. Virtual reality is used in a large variety of application domains which need multisensory...

Virtual Organizations: Beyond Network Organization

Directory of Open Access Journals (Sweden)

Liviu Gabriel CRETU

2006-01-01

Full Text Available One of the most used buzz-words in (e-business literature of the last decade is virtual organization. The term "virtual" can be identified in all sorts of combinations regarding the business world. From virtual products to virtual processes or virtual teams, everything that is “touched” by the computer’s processing power instantly becomes virtual. Moreover, most of the literature treats virtual and network organizations as being synonyms. This paper aims to draw a much more distinctive line between the two concepts. Providing a more coherent description of what virtual organization might be is also one of our intentions.

Virtual Reference Services.

Science.gov (United States)

Brewer, Sally

2003-01-01

As the need to access information increases, school librarians must create virtual libraries. Linked to reliable reference resources, the virtual library extends the physical collection and library hours and lets students learn to use Web-based resources in a protected learning environment. The growing number of virtual schools increases the need…

Effectiveness of the Virtual Reality System Toyra on Upper Limb Function in People with Tetraplegia: A Pilot Randomized Clinical Trial

Directory of Open Access Journals (Sweden)

I. Dimbwadyo-Terrer

2016-01-01

Full Text Available The aim of this study was to investigate the effects of a virtual reality program combined with conventional therapy in upper limb function in people with tetraplegia and to provide data about patients’ satisfaction with the virtual reality system. Thirty-one people with subacute complete cervical tetraplegia participated in the study. Experimental group received 15 sessions with Toyra® virtual reality system for 5 weeks, 30 minutes/day, 3 days/week in addition to conventional therapy, while control group only received conventional therapy. All patients were assessed at baseline, after intervention, and at three-month follow-up with a battery of clinical, functional, and satisfaction scales. Control group showed significant improvements in the manual muscle test (p = 0,043, partial η2 = 0,22 in the follow-up evaluation. Both groups demonstrated clinical, but nonsignificant, changes to their arm function in 4 of the 5 scales used. All patients showed a high level of satisfaction with the virtual reality system. This study showed that virtual reality added to conventional therapy produces similar results in upper limb function compared to only conventional therapy. Moreover, the gaming aspects incorporated in conventional rehabilitation appear to produce high motivation during execution of the assigned tasks. This trial is registered with EudraCT number 2015-002157-35.

Effectiveness of the Virtual Reality System Toyra on Upper Limb Function in People with Tetraplegia: A Pilot Randomized Clinical Trial.

Science.gov (United States)

Dimbwadyo-Terrer, I; Gil-Agudo, A; Segura-Fragoso, A; de los Reyes-Guzmán, A; Trincado-Alonso, F; Piazza, S; Polonio-López, B

2016-01-01

The aim of this study was to investigate the effects of a virtual reality program combined with conventional therapy in upper limb function in people with tetraplegia and to provide data about patients' satisfaction with the virtual reality system. Thirty-one people with subacute complete cervical tetraplegia participated in the study. Experimental group received 15 sessions with Toyra(®) virtual reality system for 5 weeks, 30 minutes/day, 3 days/week in addition to conventional therapy, while control group only received conventional therapy. All patients were assessed at baseline, after intervention, and at three-month follow-up with a battery of clinical, functional, and satisfaction scales. Control group showed significant improvements in the manual muscle test (p = 0,043, partial η (2) = 0,22) in the follow-up evaluation. Both groups demonstrated clinical, but nonsignificant, changes to their arm function in 4 of the 5 scales used. All patients showed a high level of satisfaction with the virtual reality system. This study showed that virtual reality added to conventional therapy produces similar results in upper limb function compared to only conventional therapy. Moreover, the gaming aspects incorporated in conventional rehabilitation appear to produce high motivation during execution of the assigned tasks. This trial is registered with EudraCT number 2015-002157-35.

Two-Stage Performance Engineering of Container-based Virtualization

Directory of Open Access Journals (Sweden)

Zheng Li

2018-02-01

Full Text Available Cloud computing has become a compelling paradigm built on compute and storage virtualization technologies. The current virtualization solution in the Cloud widely relies on hypervisor-based technologies. Given the recent booming of the container ecosystem, the container-based virtualization starts receiving more attention for being a promising alternative. Although the container technologies are generally considered to be lightweight, no virtualization solution is ideally resource-free, and the corresponding performance overheads will lead to negative impacts on the quality of Cloud services. To facilitate understanding container technologies from the performance engineering’s perspective, we conducted two-stage performance investigations into Docker containers as a concrete example. At the first stage, we used a physical machine with “just-enough” resource as a baseline to investigate the performance overhead of a standalone Docker container against a standalone virtual machine (VM. With findings contrary to the related work, our evaluation results show that the virtualization’s performance overhead could vary not only on a feature-by-feature basis but also on a job-to-job basis. Moreover, the hypervisor-based technology does not come with higher performance overhead in every case. For example, Docker containers particularly exhibit lower QoS in terms of storage transaction speed. At the ongoing second stage, we employed a physical machine with “fair-enough” resource to implement a container-based MapReduce application and try to optimize its performance. In fact, this machine failed in affording VM-based MapReduce clusters in the same scale. The performance tuning results show that the effects of different optimization strategies could largely be related to the data characteristics. For example, LZO compression can bring the most significant performance improvement when dealing with text data in our case.

Game-Based Virtual Worlds as Decentralized Virtual Activity Systems

Science.gov (United States)

Scacchi, Walt

There is widespread interest in the development and use of decentralized systems and virtual world environments as possible new places for engaging in collaborative work activities. Similarly, there is widespread interest in stimulating new technological innovations that enable people to come together through social networking, file/media sharing, and networked multi-player computer game play. A decentralized virtual activity system (DVAS) is a networked computer supported work/play system whose elements and social activities can be both virtual and decentralized (Scacchi et al. 2008b). Massively multi-player online games (MMOGs) such as World of Warcraft and online virtual worlds such as Second Life are each popular examples of a DVAS. Furthermore, these systems are beginning to be used for research, deve-lopment, and education activities in different science, technology, and engineering domains (Bainbridge 2007, Bohannon et al. 2009; Rieber 2005; Scacchi and Adams 2007; Shaffer 2006), which are also of interest here. This chapter explores two case studies of DVASs developed at the University of California at Irvine that employ game-based virtual worlds to support collaborative work/play activities in different settings. The settings include those that model and simulate practical or imaginative physical worlds in different domains of science, technology, or engineering through alternative virtual worlds where players/workers engage in different kinds of quests or quest-like workflows (Jakobsson 2006).

A receiver with in-band IIP3>20dBm, exploiting cancelling of OpAmp finite-gain-induced distortion via negative conductance

NARCIS (Netherlands)

Mahrof, D.H.; Klumperink, Eric A.M.; Oude Alink, M.S.; Nauta, Bram

2013-01-01

Highly linear CMOS radio receivers increasingly exploit linear RF V-I conversion and passive down-mixing, followed by an OpAmp based Transimpedance Amplifier at baseband. Due to the finite OpAmp gain in wideband receivers operating with large signals, virtual ground is imperfect, inducing distortion

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

Virtual reality - aesthetic consequences

OpenAIRE

Benda, Lubor

2014-01-01

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...

VISIT - Virtual visits to nuclear power plants

International Nuclear Information System (INIS)

Mollaret, Jean-Christophe

2001-01-01

For more than twenty years, EDFs Communication Division has conducted a policy of opening its generation sites to the general public. Around 300,000 people visit a nuclear power plant every year. However, for the security of persons and the safety of facilities, those parts of the plant situated in controlled areas are not accessible to visitors. For the sake of transparency, EDF has taken an interest in the technologies offered by virtual reality to show the general public what a nuclear power plant is really like, so as to initiate dialogue on nuclear energy, particularly with young people. Visit has been developed with virtual reality technologies. It serves to show the invisible (voyage to the core of fission), the inaccessible and to immerse the visitors in environments which are usually closed to the general public (discovery of the controlled area of a nuclear power plant). Visit is used in Public Information Centres which receive visitors to EDF power plants and during international exhibitions and conferences. Visit allows a virtual tour of the following controlled areas: locker room hot area/cold area, a necessary passage before entering the controlled areas; reactor building; fuel building; waste auxiliary building (liquid, solid and gaseous effluents). It also includes a tour of the rooms or equipment usually accessible to the general public: control room, turbine hall, transformer, air cooling tower

Design and evaluation of a simulation for pediatric dentistry in virtual worlds.

Science.gov (United States)

Papadopoulos, Lazaros; Pentzou, Afroditi-Evaggelia; Louloudiadis, Konstantinos; Tsiatsos, Thrasyvoulos-Konstantinos

2013-10-29

Three-dimensional virtual worlds are becoming very popular among educators in the medical field. Virtual clinics and patients are already used for case study and role play in both undergraduate and continuing education levels. Dental education can also take advantage of the virtual world's pedagogical features in order to give students the opportunity to interact with virtual patients (VPs) and practice in treatment planning. The objective of this study was to design and evaluate a virtual patient as a supplemental teaching tool for pediatric dentistry. A child VP, called Erietta, was created by utilizing the programming and building tools that online virtual worlds offer. The case is about an eight-year old girl visiting the dentist with her mother for the first time. Communication techniques such as Tell-Show-Do and parents' interference management were the basic elements of the educational scenario on which the VP was based. An evaluation of the simulation was made by 103 dental students in their fourth year of study. Two groups were formed: an experimental group which was exposed to the simulation (n=52) and a control group which did not receive the simulation (n=51). At the end, both groups were asked to complete a knowledge questionnaire and the results were compared. A statistically significant difference between the two groups was found by applying a t test for independent samples (Pworld offers significant learning potential when used as a supplement to the traditional teaching techniques.

User-centered virtual environment design for virtual rehabilitation

Directory of Open Access Journals (Sweden)

Rizzo Albert A

2010-02-01

Full Text Available Abstract Background As physical and cognitive rehabilitation protocols utilizing virtual environments transition from single applications to comprehensive rehabilitation programs there is a need for a new design cycle methodology. Current human-computer interaction designs focus on usability without benchmarking technology within a user-in-the-loop design cycle. The field of virtual rehabilitation is unique in that determining the efficacy of this genre of computer-aided therapies requires prior knowledge of technology issues that may confound patient outcome measures. Benchmarking the technology (e.g., displays or data gloves using healthy controls may provide a means of characterizing the "normal" performance range of the virtual rehabilitation system. This standard not only allows therapists to select appropriate technology for use with their patient populations, it also allows them to account for technology limitations when assessing treatment efficacy. Methods An overview of the proposed user-centered design cycle is given. Comparisons of two optical see-through head-worn displays provide an example of benchmarking techniques. Benchmarks were obtained using a novel vision test capable of measuring a user's stereoacuity while wearing different types of head-worn displays. Results from healthy participants who performed both virtual and real-world versions of the stereoacuity test are discussed with respect to virtual rehabilitation design. Results The user-centered design cycle argues for benchmarking to precede virtual environment construction, especially for therapeutic applications. Results from real-world testing illustrate the general limitations in stereoacuity attained when viewing content using a head-worn display. Further, the stereoacuity vision benchmark test highlights differences in user performance when utilizing a similar style of head-worn display. These results support the need for including benchmarks as a means of better

User-centered virtual environment design for virtual rehabilitation.

Science.gov (United States)

Fidopiastis, Cali M; Rizzo, Albert A; Rolland, Jannick P

2010-02-19

As physical and cognitive rehabilitation protocols utilizing virtual environments transition from single applications to comprehensive rehabilitation programs there is a need for a new design cycle methodology. Current human-computer interaction designs focus on usability without benchmarking technology within a user-in-the-loop design cycle. The field of virtual rehabilitation is unique in that determining the efficacy of this genre of computer-aided therapies requires prior knowledge of technology issues that may confound patient outcome measures. Benchmarking the technology (e.g., displays or data gloves) using healthy controls may provide a means of characterizing the "normal" performance range of the virtual rehabilitation system. This standard not only allows therapists to select appropriate technology for use with their patient populations, it also allows them to account for technology limitations when assessing treatment efficacy. An overview of the proposed user-centered design cycle is given. Comparisons of two optical see-through head-worn displays provide an example of benchmarking techniques. Benchmarks were obtained using a novel vision test capable of measuring a user's stereoacuity while wearing different types of head-worn displays. Results from healthy participants who performed both virtual and real-world versions of the stereoacuity test are discussed with respect to virtual rehabilitation design. The user-centered design cycle argues for benchmarking to precede virtual environment construction, especially for therapeutic applications. Results from real-world testing illustrate the general limitations in stereoacuity attained when viewing content using a head-worn display. Further, the stereoacuity vision benchmark test highlights differences in user performance when utilizing a similar style of head-worn display. These results support the need for including benchmarks as a means of better understanding user outcomes, especially for patient

Alleviating the water scarcity in the North China Plain: the role of virtual water and real water transfer

Science.gov (United States)

Zhang, Zhuoying; Yang, Hong; Shi, Minjun

2016-04-01

The North China Plain is the most water scarce region in China. Its water security is closely relevant to interregional water movement, which can be realized by real water transfers and/or virtual water transfers. This study investigates the roles of virtual water trade and real water transfer using Interregional Input-Output model. The results show that the region is receiving 19.4 billion m3/year of virtual water from the interregional trade, while exporting 16.4 billion m3/year of virtual water in the international trade. In balance, the region has a net virtual water gain of 3 billion m3/year from outside. Its virtual water inflow is dominated by agricultural products from other provinces, totalling 16.6 billion m3/year, whilst its virtual water export is dominated by manufacturing sectors to other countries, totalling 11.7 billion m3/year. Both virtual water import and real water transfer from South to North Water Diversion Project are important water supplements for the region. The results of this study provide useful scientific references for the establishment of combating strategies to deal with the water scarcity in the future.

Trends in Virtualized User Environments

Directory of Open Access Journals (Sweden)

Diane Barrett

2008-06-01

Full Text Available Virtualized environments can make forensics investigation more difficult. Technological advances in virtualization tools essentially make removable media a PC that can be carried around in a pocket or around a neck. Running operating systems and applications this way leaves very little trace on the host system. This paper will explore all the newest methods for virtualized environments and the implications they have on the world of forensics. It will begin by describing and differentiating between software and hardware virtualization. It will then move on to explain the various methods used for server and desktop virtualization. Next, it will explain how virtualization affects the basic forensic process. Finally, it will describe the common methods to find virtualization artifacts and identify virtual activities that affect the examination process of certain virtualized user environments.

High-precision positioning system of four-quadrant detector based on the database query

Science.gov (United States)

Zhang, Xin; Deng, Xiao-guo; Su, Xiu-qin; Zheng, Xiao-qiang

2015-02-01

The fine pointing mechanism of the Acquisition, Pointing and Tracking (APT) system in free space laser communication usually use four-quadrant detector (QD) to point and track the laser beam accurately. The positioning precision of QD is one of the key factors of the pointing accuracy to APT system. A positioning system is designed based on FPGA and DSP in this paper, which can realize the sampling of AD, the positioning algorithm and the control of the fast swing mirror. We analyze the positioning error of facular center calculated by universal algorithm when the facular energy obeys Gauss distribution from the working principle of QD. A database is built by calculation and simulation with MatLab software, in which the facular center calculated by universal algorithm is corresponded with the facular center of Gaussian beam, and the database is stored in two pieces of E2PROM as the external memory of DSP. The facular center of Gaussian beam is inquiry in the database on the basis of the facular center calculated by universal algorithm in DSP. The experiment results show that the positioning accuracy of the high-precision positioning system is much better than the positioning accuracy calculated by universal algorithm.

LABORATORIO VIRTUAL DE GEOMETRÍA DESCRIPTIVA

Directory of Open Access Journals (Sweden)

Juan Mato Tamayo

2016-05-01

Full Text Available El presente trabajo se realizó con el objetivo fundamental de contribuir al mejoramiento del proceso de aprendizaje por parte de los estudiantes, de los conocimientos teóricos y prácticos que se imparten en la asignatura Gráficas por Computadora, en particular en el tema de Introducción a la Geometría Descriptiva. Consiste en una aplicación informática que, a través de la interactividad con el usuario realiza la proyección ortogonal del punto y la línea en los sistemas de dos planos de proyecciones (horizontal y frontal, dando lugar a los cuadrantes y en el sistema de tres planos de proyecciones (horizontal, frontal y lateral dando lugar a los octantes. Cuenta además con opciones para ejercitar los conocimientos aprendidos y la simulación del método de abatimiento de los planos de forma manual y automatizada, así como la posibilidad de almacenar ejemplos de ejecuciones realizadas. La aplicación utiliza la biblioteca gráfica OpenGL (Open Graphics Library para la representación gráfica de las diferentes entidades geométricas en el plano (dos dimensiones y en el espacio (tres dimensiones y fue empleado el lenguaje de programación C/C++, haciendo uso del paradigma de programación orientado a objetos, basado en el cual fueron creados nuevos tipos abstractos de datos para representar las diferentes entidades geométricas necesarias. Está concebida como una aplicación de escritorio y cuenta con un archivo instalador que permite personalizar este proceso.PALABRAS CLAVE: proyección; cuadrantes; octantes; abatimiento; entidades.VIRTUAL LABORATORY PROJECTIVE GEOMETRYABSTRACTThis work was carried out in the University of Granma, the principal objective was to contribute to the betterment of the learning process for the students, of the theoretical and practical knowledge that they gave in the Computer Graphics subject, in particular the introduction to Descriptive Geometry topic. Consist in an informatical application that, trough

Model Manipulation and Learning: Fostering Representational Competence with Virtual and Concrete Models

Science.gov (United States)

Stull, Andrew T.; Hegarty, Mary

2016-01-01

This study investigated the development of representational competence among organic chemistry students by using 3D (concrete and virtual) models as aids for teaching students to translate between multiple 2D diagrams. In 2 experiments, students translated between different diagrams of molecules and received verbal feedback in 1 of the following 3…

Instructor feedback versus no instructor feedback on performance in a laparoscopic virtual reality simulator: a randomized educational trial.

Science.gov (United States)

Oestergaard, Jeanett; Bjerrum, Flemming; Maagaard, Mathilde; Winkel, Per; Larsen, Christian Rifbjerg; Ringsted, Charlotte; Gluud, Christian; Grantcharov, Teodor; Ottesen, Bent; Soerensen, Jette Led

2012-02-28

Several studies have found a positive effect on the learning curve as well as the improvement of basic psychomotor skills in the operating room after virtual reality training. Despite this, the majority of surgical and gynecological departments encounter hurdles when implementing this form of training. This is mainly due to lack of knowledge concerning the time and human resources needed to train novice surgeons to an adequate level. The purpose of this trial is to investigate the impact of instructor feedback regarding time, repetitions and self-perception when training complex operational tasks on a virtual reality simulator. The study population consists of medical students on their 4th to 6th year without prior laparoscopic experience. The study is conducted in a skills laboratory at a centralized university hospital. Based on a sample size estimation 98 participants will be randomized to an intervention group or a control group. Both groups have to achieve a predefined proficiency level when conducting a laparoscopic salpingectomy using a surgical virtual reality simulator. The intervention group receives standardized instructor feedback of 10 to 12 min a maximum of three times. The control group receives no instructor feedback. Both groups receive the automated feedback generated by the virtual reality simulator. The study follows the CONSORT Statement for randomized trials. Main outcome measures are time and repetitions to reach the predefined proficiency level on the simulator. We include focus on potential sex differences, computer gaming experience and self-perception. The findings will contribute to a better understanding of optimal training methods in surgical education. NCT01497782.

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...

Creating Virtual-hand and Virtual-face Illusions to Investigate Self-representation.

Science.gov (United States)

Ma, Ke; Lippelt, Dominique P; Hommel, Bernhard

2017-03-01

Studies investigating how people represent themselves and their own body often use variants of "ownership illusions", such as the traditional rubber-hand illusion or the more recently discovered enfacement illusion. However, these examples require rather artificial experimental setups, in which the artificial effector needs to be stroked in synchrony with the participants' real hand or face-a situation in which participants have no control over the stroking or the movements of their real or artificial effector. Here, we describe a technique to establish ownership illusions in a setup that is more realistic, more intuitive, and of presumably higher ecological validity. It allows creating the virtual-hand illusion by having participants control the movements of a virtual hand presented on a screen or in virtual space in front of them. If the virtual hand moves in synchrony with the participants' own real hand, they tend to perceive the virtual hand as part of their own body. The technique also creates the virtual-face illusion by having participants control the movements of a virtual face in front of them, again with the effect that they tend to perceive the face as their own if it moves in synchrony with their real face. Studying the circumstances that illusions of this sort can be created, increased, or reduced provides important information about how people create and maintain representations of themselves.

Virtual reality for improving balance in patients after stroke: A systematic review and meta-analysis.

Science.gov (United States)

Li, Zhen; Han, Xiu-Guo; Sheng, Jing; Ma, Shao-Jun

2016-05-01

To evaluate the effectiveness of virtual reality interventions for improving balance in people after stroke. Systematic review and meta-analysis of randomized controlled trials. Studies were obtained by searching the following databases: MEDLINE, CINAHL, EMBASE, Web of Science and CENTRAL. Two reviewers assessed studies for inclusion, extracted data and assessed trial quality. Sixteen studies involving 428 participants were included. People who received virtual reality interventions showed marked improvements in Berg Balance Scale (mean difference: 1.46, 95% confidence interval: 0.09-2.83, Pvirtual reality to improve balance after stroke. © The Author(s) 2015.

Radiation dose assessment in nuclear plants through virtual simulations using a game engine

International Nuclear Information System (INIS)

Jorge, Carlos A.F.; Mol, Antonio C. A.; Aghina, Mauricio Alves C.

2008-01-01

Full text: This paper reports an R and D which has the purpose of performing dose assessment of workers in nuclear plants, through virtual simulations using a game engine. The main objective of this R and D is to support the planning of operational and maintenance routines in nuclear plants, aiming to reduce the dose received by workers. Game engine is the core of a computer game, that is usually made independent of both the scenarios and the original applications, and thus can be adapted for any other purposes, including scientific or technological ones. Computer games have experienced a great development in the last years, regarding computer graphics, 3D image rendering and the representation of the physics needed for the virtual simulations, such as gravity effect and collision among virtual components within the games. Thus, researchers do not need to develop an entire platform for virtual simulations, what would be a hard work itself, but they can rather take advantage of such well developed platforms, adapting them for their own applications. The game engine used in this R and D is part of a computer game widely used, Unreal, that has its source code partially open, and can be pursued for low cost. A nuclear plant in our Institution, Argonauta research reactor, has been virtually modeled in 3D, and trainees can navigate virtually through it, with realistic walking velocity, and experiencing collision. The modified game engine computes and displays in real-time the dose received by a virtual person, the avatar, as it walks through the plant, from the radiation dose rate distribution assigned to the virtual environment. In the beginning of this R and D, radiation dose rate measurements were previously collected by the radiological protection service, and input off-line to the game engine. Currently, on-line measurements can be also input to it, by taking advantage of the game's networking capabilities. A real radiation monitor has been used to collect real

New technologies, virtual reality and multimedia, in Radiation Protection training; Nuevas tecnologias, realidad virtual y multimedia, aplicadaas a la formacion en proteccion radiologica

Energy Technology Data Exchange (ETDEWEB)

Felipe, A.; Sanchez-Mayoral, M. L.; Lamela, B.; Merino, A.; Sarti, F.

2003-07-01

Iberdrola Ingenieria y Consultoria (Iberinco) has developed some computer applications based in New Technologies, Virtual Reality and Multimedia, with the aim to optimise the formation and training of professionally exposed workers as well as to inform the public. The use of the new technologies could be an important help for the workers training. Virtual Reality Projects developed by Iberinco are: a) CIPRES: Interactive Calculations of Radiological Protection in a Simulation Environmental and, b) ACEWO: Workers Control Access to Nuclear Power Plants, virtual Reality could be directly applicable to several aspects related with Radiological Protection Training, for example. An application that workers could used to learn the main aspects of Radiological Protection related with: a) Physical concepts, b) Regulations, c) Use of protective clothing, d) Access into and exit out controlled areas, e) ALARA criterion. An examples is the project ACEWO. A training program based on Virtual Reality systems with simulations of procedures in which the operators could receive high doses. In this way, the operation time and dose could be minimised according to the ALARA criterion owing to the ability of repeating the exercise, or the work, as many times as be necessary, like project CIPRES. Iberinco has been developed an educational CD multimedia on nuclear energy and the protection measures foreseen in the emergency plans for the Spanish Civil Protection Agency, with the aim of being distributed to all the schools placed near a nuclear power plant. (Author) 4 refs.

APLIKASI TIGA DIMENSI VIRTUAL DENGAN MENGGUNAKAN 5DT DATA GLOVE 5 ULTRA

Directory of Open Access Journals (Sweden)

Yulia Yulia

2008-07-01

Full Text Available Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} One of active area in information technology research is development of virtual reality (VR. It is a technology which can simulate real world activities in a virtual world. Virtual reality consists of software and hardware which is usually in the form of device that captures human movement. Then VR sends signal of that movement to computer. The signal will be received and processed and shown on the screen, so that the movement can be simulated. In this research, we develop an application that can receive hand movement input with 5DT Data Glove 5 Ultra and create natural and accurate hand movement animation output for hand opening closing and other gestures. Experiments show that there are some gestures though have different physical shapes but are recognized as the same gestures because of sensor limitation in data glove.   Keywords: data glove, animation, virtual reality

Virtual data in CMS production

International Nuclear Information System (INIS)

Arbree, A. et al.

2004-01-01

Initial applications of the GriPhyN Chimera Virtual Data System have been performed within the context of CMS Production of Monte Carlo Simulated Data. The GriPhyN Chimera system consists of four primary components: (1) a Virtual Data Language, which is used to describe virtual data products, (2) a Virtual Data Catalog, which is used to store virtual data entries, (3) an Abstract Planner, which resolves all dependencies of a particular virtual data product and forms a location and existence independent plan, (4) a Concrete Planner, which maps an abstract, logical plan onto concrete, physical grid resources accounting for staging in/out files and publishing results to a replica location service. A CMS Workflow Planner, MCRunJob, is used to generate virtual data products using the Virtual Data Language. Subsequently, a prototype workflow manager, known as WorkRunner, is used to schedule the instantiation of virtual data products across a grid

Virtual Data in CMS Production

CERN Document Server

Arbree, A; Bourilkov, D; Cavanaugh, R J; Graham, G; Katageri, S; Rodríguez, J; Voeckler, J; Wilde, M

2003-01-01

Initial applications of the GriPhyN Chimera Virtual Data System have been performed within the context of CMS Production of Monte Carlo Simulated Data. The GriPhyN Chimera system consists of four primary components: 1) a Virtual Data Language, which is used to describe virtual data products, 2) a Virtual Data Catalog, which is used to store virtual data entries, 3) an Abstract Planner, which resolves all dependencies of a particular virtual data product and forms a location and existence independent plan, 4) a Concrete Planner, which maps an abstract, logical plan onto concrete, physical grid resources accounting for staging in/out files and publishing results to a replica location service. A CMS Workflow Planner, MCRunJob, is used to generate virtual data products using the Virtual Data Language. Subsequently, a prototype workflow manager, known as WorkRunner, is used to schedule the instantiation of virtual data products across a grid.

Instructor feedback versus no instructor feedback on performance in a laparoscopic virtual reality simulator: a randomized trial.

Science.gov (United States)

Strandbygaard, Jeanett; Bjerrum, Flemming; Maagaard, Mathilde; Winkel, Per; Larsen, Christian Rifbjerg; Ringsted, Charlotte; Gluud, Christian; Grantcharov, Teodor; Ottesen, Bent; Sorensen, Jette Led

2013-05-01

To investigate the impact of instructor feedback versus no instructor feedback when training a complex operational task on a laparoscopic virtual reality simulator. : Simulators are now widely accepted as a training tool, but there is insufficient knowledge about how much feedback is necessary, which is useful for sustainable implementation. A randomized trial complying with CONSORT Statement. All participants had to reach a predefined proficiency level for a complex operational task on a virtual reality simulator. The intervention group received standardized instructor feedback a maximum of 3 times. The control group did not receive instructor feedback. Participants were senior medical students without prior laparoscopic experience (n = 99). Outcome measures were time, repetitions, and performance score to reach a predefined proficiency level. Furthermore, influence of sex and perception of own surgical skills were examined. Time (in minutes) and repetitions were reduced in the intervention group (162 vs 342 minutes; P less time (in minutes) than women (P = 0.037), but no sex difference was observed for repetitions (P = 0.20). Participants in the intervention group had higher self-perception regarding surgical skills after the trial (P = 0.011). Instructor feedback increases the efficiency when training a complex operational task on a virtual reality simulator; time and repetitions used to achieve a predefined proficiency level were significantly reduced in the group that received instructor feedback compared with the control group. NCT01497782.

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...

Virtual data

International Nuclear Information System (INIS)

Bjorklund, E.

1993-01-01

In the 1970's, when computers were memory limited, operating system designers created the concept of ''virtual memory'' which gave users the ability to address more memory than physically existed. In the 1990s, many large control systems have the potential for becoming data limited. We propose that many of the principles behind virtual memory systems (working sets, locality, caching, and clustering) can also be applied to data-limited systems - creating, in effect, ''virtual data systems.'' At the Los Alamos National Laboratory's Clinton P. Anderson Meson Physics Facility (LAMPF), we have applied these principles to a moderately sized (10,000 data points) data acquisition and control system. To test the principles, we measured the system's performance during tune-up, production, and maintenance periods. In this paper, we present a general discussion of the principles of a virtual data system along with some discussion of our own implementation and the results of our performance measurements

Universidades virtuales: ¿aprendizaje real?

OpenAIRE

Valenzuela González, Jaime R.

2015-01-01

1. Introducción; 2. Modalidades educativas; 3. Concepto y características de las universidades virtuales; 4. Un modelo de universidad virtual; 5. Universidades virtuales ¿aprendizaje real?; 6. Tensiones de las universidades virtuales; 7. Referencias

MULTIMEDIA EDITOR OF VIRTUAL PHYSICAL LABORATORY IN DISTANCE LEARNING SYSTEM «KHERSON VIRTUAL UNIVERSITY»

Directory of Open Access Journals (Sweden)

Kravtsov H.

2017-12-01

Full Text Available The questions of modeling the structure of the objects of the system, the design of software modules and technologies for creating the editor of a virtual laboratory are considered. The relevance of the study is due to the lack in existing distance learning systems of support for the creation and use of virtual laboratory work on disciplines of the natural-science profile. The subject of the study is a software module for creating and using virtual laboratory work in a distance learning system. The purpose of the study is the development of a system model and a description of the software development technology of a virtual laboratory for physics for a distance learning system. The information technologies of designing the structure of the virtual laboratory and the main modes of the program module of the editor of the virtual laboratory work are described. At the heart of the structure of the software module "Virtual Laboratory" is the multimedia Web-editor of virtual laboratory works, which is created using object-oriented design technology. The program library of multimedia 3D objects created in the development environment of interactive graphic objects Unity3D. It unifies the process of creation and processing of virtual laboratory works. The basic mathematical package for supporting calculations is the mathematical processor Waterloo Maple. The application of the developed software interface will allow teachers to create laboratory works and use them in their distance courses. Students, in turn, will be able to conduct research, performing virtual laboratory work. As an example, the editor of the virtual laboratory for physics in the distance learning system "Kherson Virtual University" is considered.

Virtualized Networks and Virtualized Optical Line Terminal (vOLT)

Science.gov (United States)

Ma, Jonathan; Israel, Stephen

2017-03-01

The success of the Internet and the proliferation of the Internet of Things (IoT) devices is forcing telecommunications carriers to re-architecture a central office as a datacenter (CORD) so as to bring the datacenter economics and cloud agility to a central office (CO). The Open Network Operating System (ONOS) is the first open-source software-defined network (SDN) operating system which is capable of managing and controlling network, computing, and storage resources to support CORD infrastructure and network virtualization. The virtualized Optical Line Termination (vOLT) is one of the key components in such virtualized networks.

A study on development of virtual panel and virtual collaboration system

International Nuclear Information System (INIS)

Yoo, H. J.; Park, S. Y.; Lee, M. S.; Hong, J. H.

2001-01-01

The Nuclear I and C group of KEPRI has been peforming research and development on the VRCATS, Virtual Reality based Computer Assisted Training System. For the past two years, we have developed the first VRCATS for Youngkwang 1 nuclear power plant. Currently, we are developing an advanced VRCATS for Uljin 3 nuclear power plant. In this paepr, we will describe virtual panel system and VR based collaborate training system (VRCATS) of the Uljin VRCATS. Since Virtual Panel provides the same environment as the real MCR, trainees can expect the same training effect with Virtual Panel as they do with full scope simulator. i.e., trainees can check key variables and operate the plants and get responses with Virtual Panel. VRCTS provides another realistic training environment for trainees. In VRCATS, for example, operators in a group can work together t handle LOCA (Loss of Coolant Accident) according to emergency operation procedures

ADEPT - an innovative tool to reduce worker exposure using virtual job planning

Energy Technology Data Exchange (ETDEWEB)

Verzilov, Y.; Husain, A. [Kinectrics Inc., Toronto, Ontario (Canada); Trifanov, A. [SoftBeam Ltd., Montreal, Quebec (Canada)

2011-07-01

Advanced Dose Exposure Planning Tool (ADEPT) is Kinectrics' innovative solution for assisting nuclear station staff to effectively minimize worker dose during inspection and maintenance activities. ADEPT is a PC-based software that provides 3D virtual reality job simulations for radioactive environments around the CANDU reactor components, namely, the horizontal feeder cabinet, the vertical feeder cabinet and the reactor face. ADEPT allows users to walk through a virtual job plan and receive a live radiation dose estimate for the planned work. A worker dose estimation is based on a predetermined radiation field around reactor components and a user-defined job description. Radiation fields are based on the Outage Activity Transport Monitoring (OATM) data. (author)

ADEPT - an innovative tool to reduce worker exposure using virtual job planning

International Nuclear Information System (INIS)

Verzilov, Y.; Husain, A.; Trifanov, A.

2011-01-01

Advanced Dose Exposure Planning Tool (ADEPT) is Kinectrics' innovative solution for assisting nuclear station staff to effectively minimize worker dose during inspection and maintenance activities. ADEPT is a PC-based software that provides 3D virtual reality job simulations for radioactive environments around the CANDU reactor components, namely, the horizontal feeder cabinet, the vertical feeder cabinet and the reactor face. ADEPT allows users to walk through a virtual job plan and receive a live radiation dose estimate for the planned work. A worker dose estimation is based on a predetermined radiation field around reactor components and a user-defined job description. Radiation fields are based on the Outage Activity Transport Monitoring (OATM) data. (author)

Virtual reality job interview training and 6-month employment outcomes for individuals with schizophrenia seeking employment.

Science.gov (United States)

Smith, Matthew J; Fleming, Michael F; Wright, Michael A; Roberts, Andrea G; Humm, Laura Boteler; Olsen, Dale; Bell, Morris D

2015-08-01

Individuals with schizophrenia have low employment rates and the job interview presents a critical barrier for them to obtain employment. Virtual reality training has demonstrated efficacy at improving interview skills and employment outcomes among multiple clinical populations. However, the effects of this training on individuals with schizophrenia are unknown. This study evaluated the efficacy of virtual reality job interview training (VR-JIT) at improving job interview skills and employment outcomes among individuals with schizophrenia in a small randomized controlled trial (n=21 VR-JIT trainees, n=11 waitlist controls). Trainees completed up to 10h of virtual interviews using VR-JIT, while controls received services as usual. Primary outcome measures included two pre-test and two post-test video-recorded role-play interviews scored by blinded raters with expertise in human resources and self-reported interviewing self-confidence. Six-month follow-up data on employment outcomes were collected. Trainees reported that the intervention was easy-to-use, helpful, and prepared them for future interviews. Trainees demonstrated increased role-play scores between pre-test and post-test while controls did not (p=0.001). After accounting for neurocognition and months since prior employment, trainees had greater odds of receiving a job offer by 6month follow-up compared to controls (OR: 8.73, p=0.04) and more training was associated with fewer weeks until receiving a job offer (r=-0.63, pjob interview skills in individuals with schizophrenia. Moreover, trainees had greater odds of receiving a job offer by 6-month follow-up. Future studies could evaluate the effectiveness of VR-JIT within community-based services. Copyright © 2015 Elsevier B.V. All rights reserved.

Using virtual machine monitors to overcome the challenges of monitoring and managing virtualized cloud infrastructures

Science.gov (United States)

Bamiah, Mervat Adib; Brohi, Sarfraz Nawaz; Chuprat, Suriayati

2012-01-01

Virtualization is one of the hottest research topics nowadays. Several academic researchers and developers from IT industry are designing approaches for solving security and manageability issues of Virtual Machines (VMs) residing on virtualized cloud infrastructures. Moving the application from a physical to a virtual platform increases the efficiency, flexibility and reduces management cost as well as effort. Cloud computing is adopting the paradigm of virtualization, using this technique, memory, CPU and computational power is provided to clients' VMs by utilizing the underlying physical hardware. Beside these advantages there are few challenges faced by adopting virtualization such as management of VMs and network traffic, unexpected additional cost and resource allocation. Virtual Machine Monitor (VMM) or hypervisor is the tool used by cloud providers to manage the VMs on cloud. There are several heterogeneous hypervisors provided by various vendors that include VMware, Hyper-V, Xen and Kernel Virtual Machine (KVM). Considering the challenge of VM management, this paper describes several techniques to monitor and manage virtualized cloud infrastructures.

Organization Virtual or Networked?

Directory of Open Access Journals (Sweden)

Rūta Tamošiūnaitė

2013-08-01

Full Text Available 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 organization” are presented.Originality/Value—distinction between “virtual organization” and “networked organization” creates possibilities to use all advantages of those types of organizations and gives foundation for deeper researches in this field.Research type: general review.

Perception of Virtual Audiences.

Science.gov (United States)

Chollet, Mathieu; Scherer, Stefan

2017-01-01

A growing body of evidence shows that virtual audiences are a valuable tool in the treatment of social anxiety, and recent works show that it also a useful in public-speaking training programs. However, little research has focused on how such audiences are perceived and on how the behavior of virtual audiences can be manipulated to create various types of stimuli. The authors used a crowdsourcing methodology to create a virtual audience nonverbal behavior model and, with it, created a dataset of videos with virtual audiences containing varying behaviors. Using this dataset, they investigated how virtual audiences are perceived and which factors affect this perception.

Virtual School Startups: Founder Processes in American K-12 Public Virtual Schools

Science.gov (United States)

Taylor, Brett D.; McNair, Delores E.

2018-01-01

Traditional school districts do not have a lot of experience with virtual schools and have lost students to state and charter virtual schools. To retain students and offer alternative learning opportunities, more public districts are starting their own virtual schools. This study was an examination of foundational processes at three California…

Virtual expansion of the technical vision system for smart vehicles based on multi-agent cooperation model

Science.gov (United States)

Krapukhina, Nina; Senchenko, Roman; Kamenov, Nikolay

2017-12-01

Road safety and driving in dense traffic flows poses some challenges in receiving information about surrounding moving object, some of which can be in the vehicle's blind spot. This work suggests an approach to virtual monitoring of the objects in a current road scene via a system with a multitude of cooperating smart vehicles exchanging information. It also describes the intellectual agent model, and provides methods and algorithms of identifying and evaluating various characteristics of moving objects in video flow. Authors also suggest ways for integrating the information from the technical vision system into the model with further expansion of virtual monitoring for the system's objects. Implementation of this approach can help to expand the virtual field of view for a technical vision system.

Leader competencies in virtual organization

OpenAIRE

Bulinska-Stangrecka, Helena

2018-01-01

This paper discusses the competence required in the leadership of virtual organization. The specics of virtual organization presents a challenge to traditional managerial styles. In order to achieve success in virtual environment, a leader must develop specic abilities. This analysis examines the uniqueness of the virtual organization, including team work and management. The last part presents ndings and summaries regarding e€ective e-leadership requirement. A virtual leader ma...

Virtual Reality: An Overview.

Science.gov (United States)

Franchi, Jorge

1994-01-01

Highlights of this overview of virtual reality include optics; interface devices; virtual worlds; potential applications, including medicine and archaeology; problems, including costs; current research and development; future possibilities; and a listing of vendors and suppliers of virtual reality products. (Contains 11 references.) (LRW)

[Effectiveness of a programme based on a virtual reality game for cognitive enhancement in schizophrenia].

Science.gov (United States)

López-Martín, Olga; Segura Fragoso, Antonio; Rodríguez Hernández, Marta; Dimbwadyo Terrer, Iris; Polonio-López, Begoña

2016-01-01

To evaluate the effectiveness of a programme based on a virtual reality game to improve cognitive domains in patients with schizophrenia. A randomized controlled trial was conducted in 40 patients with schizophrenia, 20 in the experimental group and 20 in the control group. The experimental group received 10 sessions with Nintendo Wii(®) for 5 weeks, 50 minutes/session, 2 days/week in addition to conventional treatment. The control group received conventional treatment only. Statistically significant differences in the T-Score were found in 5 of the 6 cognitive domains assessed: processing speed (F=12.04, p=0.001), attention/vigilance (F=12.75, p=0.001), working memory (F=18.86, p virtual reality interventions aimed at cognitive training have great potential for significant gains in different cognitive domains assessed in patients with schizophrenia. Copyright © 2015 SESPAS. Published by Elsevier Espana. All rights reserved.

Virtual currencies- Real opportunities?

OpenAIRE

Selldahl, Sara

2013-01-01

The European Central Bank defines virtual currencies as ”unregulated, digital money, which is issued and usually controlled by its developers, and used and accepted among the members of a specific virtual community.” (European Central Bank, 2012, p. 5) The interest in virtual currencies has increased immensely over the last few years as they become increasingly prevalent in our society across many different industries. Up until now, the field of virtual currencies has been mainly uncharted ...

Agreements in Virtual Organizations

Science.gov (United States)

Pankowska, Malgorzata

This chapter is an attempt to explain the important impact that contract theory delivers with respect to the concept of virtual organization. The author believes that not enough research has been conducted in order to transfer theoretical foundations for networking to the phenomena of virtual organizations and open autonomic computing environment to ensure the controllability and management of them. The main research problem of this chapter is to explain the significance of agreements for virtual organizations governance. The first part of this chapter comprises explanations of differences among virtual machines and virtual organizations for further descriptions of the significance of the first ones to the development of the second. Next, the virtual organization development tendencies are presented and problems of IT governance in highly distributed organizational environment are discussed. The last part of this chapter covers analysis of contracts and agreements management for governance in open computing environments.

Virtual Machine in Automation Projects

OpenAIRE

Xing, Xiaoyuan

2010-01-01

Virtual machine, as an engineering tool, has recently been introduced into automation projects in Tetra Pak Processing System AB. The goal of this paper is to examine how to better utilize virtual machine for the automation projects. This paper designs different project scenarios using virtual machine. It analyzes installability, performance and stability of virtual machine from the test results. Technical solutions concerning virtual machine are discussed such as the conversion with physical...

Instructor feedback versus no instructor feedback on performance in a laparoscopic virtual reality simulator: a randomized educational trial

Directory of Open Access Journals (Sweden)

Oestergaard Jeanett

2012-02-01

Full Text Available Abstract Background Several studies have found a positive effect on the learning curve as well as the improvement of basic psychomotor skills in the operating room after virtual reality training. Despite this, the majority of surgical and gynecological departments encounter hurdles when implementing this form of training. This is mainly due to lack of knowledge concerning the time and human resources needed to train novice surgeons to an adequate level. The purpose of this trial is to investigate the impact of instructor feedback regarding time, repetitions and self-perception when training complex operational tasks on a virtual reality simulator. Methods/Design The study population consists of medical students on their 4th to 6th year without prior laparoscopic experience. The study is conducted in a skills laboratory at a centralized university hospital. Based on a sample size estimation 98 participants will be randomized to an intervention group or a control group. Both groups have to achieve a predefined proficiency level when conducting a laparoscopic salpingectomy using a surgical virtual reality simulator. The intervention group receives standardized instructor feedback of 10 to 12 min a maximum of three times. The control group receives no instructor feedback. Both groups receive the automated feedback generated by the virtual reality simulator. The study follows the CONSORT Statement for randomized trials. Main outcome measures are time and repetitions to reach the predefined proficiency level on the simulator. We include focus on potential sex differences, computer gaming experience and self-perception. Discussion The findings will contribute to a better understanding of optimal training methods in surgical education. Trial Registration NCT01497782

Instructor feedback versus no instructor feedback on performance in a laparoscopic virtual reality simulator: a randomized educational trial

Science.gov (United States)

2012-01-01

Abstract Background Several studies have found a positive effect on the learning curve as well as the improvement of basic psychomotor skills in the operating room after virtual reality training. Despite this, the majority of surgical and gynecological departments encounter hurdles when implementing this form of training. This is mainly due to lack of knowledge concerning the time and human resources needed to train novice surgeons to an adequate level. The purpose of this trial is to investigate the impact of instructor feedback regarding time, repetitions and self-perception when training complex operational tasks on a virtual reality simulator. Methods/Design The study population consists of medical students on their 4th to 6th year without prior laparoscopic experience. The study is conducted in a skills laboratory at a centralized university hospital. Based on a sample size estimation 98 participants will be randomized to an intervention group or a control group. Both groups have to achieve a predefined proficiency level when conducting a laparoscopic salpingectomy using a surgical virtual reality simulator. The intervention group receives standardized instructor feedback of 10 to 12 min a maximum of three times. The control group receives no instructor feedback. Both groups receive the automated feedback generated by the virtual reality simulator. The study follows the CONSORT Statement for randomized trials. Main outcome measures are time and repetitions to reach the predefined proficiency level on the simulator. We include focus on potential sex differences, computer gaming experience and self-perception. Discussion The findings will contribute to a better understanding of optimal training methods in surgical education. Trial Registration NCT01497782 PMID:22373062

Virtual reality applications to the training; Aplicaciones de la realidad virtual en el entrenamiento

Energy Technology Data Exchange (ETDEWEB)

Gomez-Arguello, B.; Gonzalez, F.; Salve, R.

2003-07-01

The application of Virtual Reality for training in radiological environments allows the planning analysis and training in tasks which will be performed later in a real environment, saving doses to the real workers. There are many advantages of using VR in the training field comparing with a traditional training based on entries to the radiological areas and 2D studies: The application of the VR to the nuclear industry will provide in a middle period a more efficient training in radiological environments, giving more fidelity to the real world, enforcing the spatial skills and the active learning and allowing the visualization of the radiation field and the more suitable routes. TECNATOM has been working in VR field through several to test the adequacy of this methodology. Specifically, the SIMU2 project has been developed. This is a Virtual Reality highly flexible based software tool which allows for the simulation of human tasks in radiological environments, providing dosimetric information in all the points of the environment as well as the doses received by the workers during the simulated tasks performance. This application can be used as a support tool in training courses, to train the operators who will perform the real operation. Besides, the system allows the trainer to enter comments and explanations for each selected action or for the complete task. (Author) 8 refs.

The Virtuality Continuum Revisited

NARCIS (Netherlands)

Nijholt, Antinus; Traum, D.; Zhai, Sh.; Kellogg, W.

2005-01-01

We survey the themes and the aims of a workshop devoted to the state-of-the-art virtuality continuum. In this continuum, ranging from fully virtual to real physical environments, allowing for mixed, augmented and desktop virtual reality, several perspectives can be taken. Originally, the emphasis

The virtual nose: a 3-dimensional virtual reality model of the human nose.

Science.gov (United States)

Vartanian, A John; Holcomb, Joi; Ai, Zhuming; Rasmussen, Mary; Tardy, M Eugene; Thomas, J Regan

2004-01-01

The 3-dimensionally complex interplay of soft tissue, cartilaginous, and bony elements makes the mastery of nasal anatomy difficult. Conventional methods of learning nasal anatomy exist, but they often involve a steep learning curve. Computerized models and virtual reality applications have been used to facilitate teaching in a number of other complex anatomical regions, such as the human temporal bone and pelvic floor. We present a 3-dimensional (3-D) virtual reality model of the human nose. Human cadaveric axial cross-sectional (0.33-mm cuts) photographic data of the head and neck were used. With 460 digitized images, individual structures were traced and programmed to create a computerized polygonal model of the nose. Further refinements to this model were made using a number of specialized computer programs. This 3-D computer model of the nose was then programmed to operate as a virtual reality model. Anatomically correct 3-D model of the nose was produced. High-resolution images of the "virtual nose" demonstrate the nasal septum, lower lateral cartilages, middle vault, bony dorsum, and other structural details of the nose. Also, the model can be combined with a separate virtual reality model of the face and its skin cover as well as the skull. The user can manipulate the model in space, examine 3-D anatomical relationships, and fade superficial structures to reveal deeper ones. The virtual nose is a 3-D virtual reality model of the nose that is accurate and easy to use. It can be run on a personal computer or in a specialized virtual reality environment. It can serve as an effective teaching tool. As the first virtual reality model of the nose, it establishes a virtual reality platform from which future applications can be launched.

Virtual Museums as Educational Tool

DEFF Research Database (Denmark)

2007-01-01

Virtual Museums as Educational Tool On this web site you will find a collection of resources on virtual museums. The web site is meant to be a knowledge base for people with interest in museums, virtuality and education, and how virtual museums may contribute to adult education and lifelong...

[Virtual reality in neurosurgery].

Science.gov (United States)

Tronnier, V M; Staubert, A; Bonsanto, M M; Wirtz, C R; Kunze, S

2000-03-01

Virtual reality enables users to immerse themselves in a virtual three-dimensional world and to interact in this world. The simulation is different from the kind in computer games, in which the viewer is active but acts in a nonrealistic world, or on the TV screen, where we are passively driven in an active world. In virtual reality elements look realistic, they change their characteristics and have almost real-world unpredictability. Virtual reality is not only implemented in gambling dens and the entertainment industry but also in manufacturing processes (cars, furniture etc.), military applications and medicine. Especially the last two areas are strongly correlated, because telemedicine or telesurgery was originated for military reasons to operate on war victims from a secure distance or to perform surgery on astronauts in an orbiting space station. In medicine and especially neurosurgery virtual-reality methods are used for education, surgical planning and simulation on a virtual patient.

Study on virtual instrument developing system based on intelligent virtual control

International Nuclear Information System (INIS)

Tang Baoping; Cheng Fabin; Qin Shuren

2005-01-01

The paper introduces a non-programming developing system of a virtual instrument (VI), i.e., a virtual measurement instrument developing system (VMIDS) based on intelligent virtual control (IVC). The background of the IVC-based VMIDS is described briefly, and the hierarchical message bus (HMB)-based software architecture of VMIDS is discussed in detail. The three parts and functions of VMIDS are introduced, and the process of non-programming developing VI is further described

Study on virtual instrument developing system based on intelligent virtual control

Energy Technology Data Exchange (ETDEWEB)

Tang Baoping; Cheng Fabin; Qin Shuren [Test Center, College of Mechanical Engineering, Chongqing University , Chongqing 400030 (China)

2005-01-01

The paper introduces a non-programming developing system of a virtual instrument (VI), i.e., a virtual measurement instrument developing system (VMIDS) based on intelligent virtual control (IVC). The background of the IVC-based VMIDS is described briefly, and the hierarchical message bus (HMB)-based software architecture of VMIDS is discussed in detail. The three parts and functions of VMIDS are introduced, and the process of non-programming developing VI is further described.

Virtual Reality Design: How Head-Mounted Displays Change Design Paradigms of Virtual Reality Worlds

Directory of Open Access Journals (Sweden)

Christian Stein

2016-09-01

Full Text Available With the upcoming generation of virtual reality HMDs, new virtual worlds, scenarios, and games are created especially for them. These are no longer bound to a remote screen or a relatively static user, but to an HMD as a more immersive device. This article discusses requirements for virtual scenarios implemented in new-generation HMDs to achieve a comfortable user experience. Furthermore, the effects of positional tracking are introduced and the relation between the user’s virtual and physical body is analyzed. The observations made are exemplified by existing software prototypes. They indicate how the term “virtual reality,” with all its loaded connotations, may be reconceptualized to express the peculiarities of HMDs in the context of gaming, entertainment, and virtual experiences.

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, ...

Sobre objetos y experiencias virtuales

OpenAIRE

Pacho, Julián

2009-01-01

This paper analyses basic onto-epistemological properties of the virtual reality and suggests these theses. First, the virtual reality establishes a new nature; its essential feature is to be an organic world of emancipated techno-theories. Second, the virtual reality doesn’t substitutes the traditional book; it substitutes the world. Third, the experience of the world in the virtual reality excludes the natural world experience. Fourth, the ontology of virtual reality is build without an act...

Comparison of analgesic efficacy of four-quadrant transversus abdominis plane (TAP) block and continuous posterior TAP analgesia with epidural analgesia in patients undergoing laparoscopic colorectal surgery: an open-label, randomised, non-inferiority trial.

Science.gov (United States)

Niraj, G; Kelkar, A; Hart, E; Horst, C; Malik, D; Yeow, C; Singh, B; Chaudhri, S

2014-04-01

Posterior transversus abdominis plane blocks have been reported to be an effective method of providing analgesia after lower abdominal surgery. We compared the efficacy of a novel technique of providing continuous transversus abdominis plane analgesia with epidural analgesia in patients on an enhanced recovery programme following laparoscopic colorectal surgery. A non-inferiority comparison was used. Adult patients undergoing elective laparoscopic colorectal surgery were randomly assigned to receive continuous transversus abdominis plane analgesia (n = 35) vs epidural analgesia (n = 35), in addition to a postoperative analgesic regimen comprising regular paracetamol, regular diclofenac and tramadol as required. Sixty-one patients completed the study. The transversus group received four-quadrant transversus abdominis plane blocks and bilateral posterior transversus abdominis plane catheters that were infused with levobupivacaine 0.25% for 48 h. The epidural group received an infusion of bupivacaine and fentanyl. The primary outcome measure was visual analogue scale pain score on coughing at 24 h after surgery. We found no significant difference in median (IQR [range]) visual analogue scores during coughing at 24 h between the transversus group 2.5 (1.0-3.0 [0-5.5]) and the epidural group 2.5 (1.0-5.0 [0-6.0]). The one-sided 97.5% CI was a 0.0 (∞-1.0) difference in means, establishing non-inferiority. There were no significant differences between the groups for tramadol consumption. Success rate was 28/30 (93%) in the transversus group vs 27/31 (87%) in the epidural group. Continuous transversus abdominis plane infusion was non-inferior to epidural infusion in providing analgesia after laparoscopic colorectal surgery. © 2013 The Association of Anaesthetists of Great Britain and Ireland.

Etnografía virtual Virtual ethnography: exploring a methodological option for the research on virtual learning environments.

Directory of Open Access Journals (Sweden)

Álvarez Cadavid Gloria María

2009-01-01

Full Text Available Este artículo pretende esbozar algunas de las consideraciones metodológicas que hoy confluyen en el estudio de los ambientes virtuales, desde la opción etnográfica. De manera específica se quiere observar la forma en que, algunos investigadores han abordado el aspecto metodológico para estudiar los ambientes virtuales, líneas de evolución y posible contribución al conocimiento y mejoramiento de los procesos de e-learning. This article aims to outline some methodological considerations that merge together on the study of virtual learning environments, especially from the ethnographic perspective. Specifically, what we want to observe, is the way some researchers have approached the methodological aspect in order to study virtual learning environments, the evolution lines and the possible contribution they’ve made to knowledge and improvement of e-learning processes.

Photon virtual bound state

International Nuclear Information System (INIS)

Inoue, J.; Ohtaka, K.

2004-01-01

We study virtual bound states in photonics, which are a vectorial extension of electron virtual bound states. The condition for these states is derived. It is found that the Mie resonant state which satisfies the condition that the size parameter is less than the angular momentum should be interpreted as a photon virtual bound state. In order to confirm the validity of the concept, we compare the photonic density of states, the width of which represents the lifetime of the photon virtual bound states, with numerical results

[Research on the virtual water composition and virtual water trade for agriculture in Beijing].

Science.gov (United States)

Wang, Hong-rui; Wang, Yan; Wang, Jun-hong; Dong, Yan-yan; Han, Zhao-xing

2007-12-01

Based on the irrigation norm of typical district and county, and revised by the isoline map of Chinese crops water demand, the change of crops program was analyzed as well as the agricultural water use and its GDP benefits. Then the virtual water was calculated for years. At last, the input-output method was used to calculate the trade of virtual water in Beijing. As the results, the virtual water for cereal crops has been decreasing in Beijing, from 1.832 x 10(9) m3 in 1990 to 4.283 x 10(8) m3 in 2004. Otherwise the virtual water for technical crops has been increasing, which is from 9.06 x 10(8) m3 in 1990 to 1.492 x 10(9) m3 in 2004. On the whole, the virtual water for crops has been decreasing in Beijing. From the angle of primary products Beijing is a virtual water importing area. Virtual water importing of annual average is 2.37 x 10(8) m3, which is about 5.93% of the total water of Beijing. Virtual water has been an important supplement of local real water of Beijing.

Benchmarking Distance Control and Virtual Drilling for Lateral Skull Base Surgery.

Science.gov (United States)

Voormolen, Eduard H J; Diederen, Sander; van Stralen, Marijn; Woerdeman, Peter A; Noordmans, Herke Jan; Viergever, Max A; Regli, Luca; Robe, Pierre A; Berkelbach van der Sprenkel, Jan Willem

2018-01-01

Novel audiovisual feedback methods were developed to improve image guidance during skull base surgery by providing audiovisual warnings when the drill tip enters a protective perimeter set at a distance around anatomic structures ("distance control") and visualizing bone drilling ("virtual drilling"). To benchmark the drill damage risk reduction provided by distance control, to quantify the accuracy of virtual drilling, and to investigate whether the proposed feedback methods are clinically feasible. In a simulated surgical scenario using human cadavers, 12 unexperienced users (medical students) drilled 12 mastoidectomies. Users were divided into a control group using standard image guidance and 3 groups using distance control with protective perimeters of 1, 2, or 3 mm. Damage to critical structures (sigmoid sinus, semicircular canals, facial nerve) was assessed. Neurosurgeons performed another 6 mastoidectomy/trans-labyrinthine and retro-labyrinthine approaches. Virtual errors as compared with real postoperative drill cavities were calculated. In a clinical setting, 3 patients received lateral skull base surgery with the proposed feedback methods. Users drilling with distance control protective perimeters of 3 mm did not damage structures, whereas the groups using smaller protective perimeters and the control group injured structures. Virtual drilling maximum cavity underestimations and overestimations were 2.8 ± 0.1 and 3.3 ± 0.4 mm, respectively. Feedback methods functioned properly in the clinical setting. Distance control reduced the risks of drill damage proportional to the protective perimeter distance. Errors in virtual drilling reflect spatial errors of the image guidance system. These feedback methods are clinically feasible. Copyright © 2017 Elsevier Inc. All rights reserved.

Measurement of angularly dependent spectra of betatron gamma-rays from a laser plasma accelerator with quadrant-sectored range filters

Energy Technology Data Exchange (ETDEWEB)

Jeon, Jong Ho, E-mail: jhjeon07@ibs.re.kr; Nakajima, Kazuhisa, E-mail: naka115@dia-net.ne.jp; Rhee, Yong Joo; Pathak, Vishwa Bandhu; Cho, Myung Hoon; Shin, Jung Hun; Yoo, Byung Ju; Jo, Sung Ha; Shin, Kang Woo [Center for Relativistic Laser Science, Institute for Basic Science (IBS), Gwangju 61005 (Korea, Republic of); Kim, Hyung Taek; Sung, Jae Hee; Lee, Seong Ku; Choi, Il Woo [Center for Relativistic Laser Science, Institute for Basic Science (IBS), Gwangju 61005 (Korea, Republic of); Advanced Photonics Research Institute, GIST, Gwangju 61005 (Korea, Republic of); Hojbota, Calin; Bae, Lee Jin; Jung, Jaehyung; Cho, Min Sang; Cho, Byoung Ick; Nam, Chang Hee [Center for Relativistic Laser Science, Institute for Basic Science (IBS), Gwangju 61005 (Korea, Republic of); Department of Physics and Photon Science, GIST, Gwangju 61005 (Korea, Republic of)

2016-07-15

Measurement of angularly dependent spectra of betatron gamma-rays radiated by GeV electron beams from laser wakefield accelerators (LWFAs) are presented. The angle-resolved spectrum of betatron radiation was deconvolved from the position dependent data measured for a single laser shot with a broadband gamma-ray spectrometer comprising four-quadrant sectored range filters and an unfolding algorithm, based on the Monte Carlo code GEANT4. The unfolded gamma-ray spectra in the photon energy range of 0.1–10 MeV revealed an approximately isotropic angular dependence of the peak photon energy and photon energy-integrated fluence. As expected by the analysis of betatron radiation from LWFAs, the results indicate that unpolarized gamma-rays are emitted by electrons undergoing betatron motion in isotropically distributed orbit planes.

Neural mechanisms of behavioral change in young adults with high-functioning autism receiving virtual reality social cognition training: A pilot study.

Science.gov (United States)

Yang, Y J Daniel; Allen, Tandra; Abdullahi, Sebiha M; Pelphrey, Kevin A; Volkmar, Fred R; Chapman, Sandra B

2018-05-01

Measuring treatment efficacy in individuals with Autism Spectrum Disorder (ASD) relies primarily on behaviors, with limited evidence as to the neural mechanisms underlying these behavioral gains. This pilot study addresses this void by investigating neural and behavioral changes in a Phase I trial in young adults with high-functioning ASD who received an evidence-based behavioral intervention, Virtual Reality-Social Cognition Training over 5 weeks for a total of 10 hr. The participants were tested pre- and post-training with a validated biological/social versus scrambled/nonsocial motion neuroimaging task, previously shown to activate regions within the social brain networks. Three significant brain-behavior changes were identified. First, the right posterior superior temporal sulcus, a hub for socio-cognitive processing, showed increased brain activation to social versus nonsocial stimuli in individuals with greater gains on a theory-of-mind measure. Second, the left inferior frontal gyrus, a region for socio-emotional processing, tracked individual gains in emotion recognition with decreased activation to social versus nonsocial stimuli. Finally, the left superior parietal lobule, a region for visual attention, showed significantly decreased activation to nonsocial versus social stimuli across all participants, where heightened attention to nonsocial contingencies has been considered a disabling aspect of ASD. This study provides, albeit preliminary, some of the first evidence of the harnessable neuroplasticity in adults with ASD through an age-appropriate intervention in brain regions tightly linked to social abilities. This pilot trial motivates future efforts to develop and test social interventions to improve behaviors and supporting brain networks in adults with ASD. Autism Res 2018, 11: 713-725. © 2018 The Authors Autism Research published by International Society for Autism Research and Wiley Periodicals, Inc. This study addresses how the behavioral

An industrial application virtual reality. An aid for designing maintenance in nuclear plants

International Nuclear Information System (INIS)

Fertey, G.; Thibault, G.; Delpy, T.; Lapierre, M.

1995-09-01

This paper shows a use of virtual reality in the industrial context of nuclear plant maintenance. The objective is to build a realistic simulation fool by means of virtual reality techniques. With such a tool, the designer of a maintenance operation can validate tools and sequencing of operations, reduce the time of intervention and minimize the radiation doses received by the operator on site. Several major functionalities have been studied: a navigation in 3D geometries faithfully reproducing terrain, geometries obtained by 3D digitization of installations; an optimized navigation to the intervention sites with both management of obstacles present along the way and room walls and guiding of navigator from one room to another by means of visual indicators (arrows) which he can capture and which virtually carry him; a programming of the environment in keeping with and translating faithfully the breakdown and sequencing of intervention operations; real time information on the surrounding radiation. (author)

Art in virtual reality 2010

Science.gov (United States)

Chang, Ben

2010-01-01

For decades, virtual reality artwork has existed in a small but highly influential niche in the world of electronic and new media art. Since the early 1990's, virtual reality installations have come to define an extreme boundary point of both aesthetic experience and technological sophistication. Classic virtual reality artworks have an almost mythological stature - powerful, exotic, and often rarely exhibited. Today, art in virtual environments continues to evolve and mature, encompassing everything from fully immersive CAVE experiences to performance art in Second Life to the use of augmented and mixed reality in public space. Art in Virtual Reality 2010 is a public exhibition of new artwork that showcases the diverse ways that contemporary artists use virtual environments to explore new aesthetic ground and investigate the continually evolving relationship between our selves and our virtual worlds.

Does Narrative Feedback Enhance Children's Motor Learning in a Virtual Environment?

Science.gov (United States)

Levac, Danielle E; Lu, Amy S

2018-04-30

Augmented feedback has motivational and informational functions in motor learning, and is a key feature of practice in a virtual environment (VE). This study evaluated the impact of narrative (story-based) feedback as compared to standard feedback during practice of a novel task in a VE on typically developing children's motor learning, motivation and engagement. Thirty-eight children practiced navigating through a virtual path, receiving narrative or non-narrative feedback following each trial. All participants improved their performance on retention but not transfer, with no significant differences between groups. Self-reported engagement was associated with acquisition, retention and transfer for both groups. A narrative approach to feedback delivery did not offer an additive benefit; additional affective advantages of augmented feedback for motor learning in VEs should be explored.

Comparative Analysis of Virtual Education Applications

Directory of Open Access Journals (Sweden)

Mehmet KURT

2006-10-01

Full Text Available The research was conducted in order to make comparative analysis of virtual education applications. The research is conducted in survey model. The study group consists of total 300 institutes providing virtual education in the fall, spring and summer semesters of 2004; 246 in USA, 10 in Australia, 3 in South Africa, 10 in India, 21 in UK, 6 in Japan, 4 in Turkey. The information has been collected by online questionnaire sent to the target mass by e-mail. The questionnaire has been developed in two information categories as personal information and institutes and their virtual education applications. The English web design of the online questionnaire and the database has been prepared by Microsoft ASP codes which is the script language of Microsoft Front Page editor and has been tested on personal web site. The questionnaire has been pre applied in institutions providing virtual education in Australia. The English text of the questionnaire and web site design have been sent to educational technology and virtual education specialists in the countries of the study group. With the feedback received, the spelling mistakes have been corrected and concept and language validity have been completed. The application of the questionnaire has taken 40 weeks during March-November 2004. Only 135 institutes have replied. Two of the questionnaires have been discharged because they included mistaken coding, names of the institutions and countries. Valid 133 questionnaires cover approximately 44% of the study group. Questionnaires saved in the online database have been transferred to Microsoft Excel and then to SPSS by external database connection. In regards of the research objectives, the data collected has been analyzed on computer and by using SPSS statistics package program. In data analysis frequency (f, percentage (% and arithmetic mean ( have been used. In comparisons of country, institute, year, and other variables, che-square test, independent t

New technologies, virtual reality and multimedia, in Radiation Protection training

International Nuclear Information System (INIS)

Felipe, A.; Sanchez-Mayoral, M. L.; Lamela, B.; Merino, A.; Sarti, F.

2003-01-01

Iberdrola Ingenieria y Consultoria (Iberinco) has developed some computer applications based in New Technologies, Virtual Reality and Multimedia, with the aim to optimise the formation and training of professionally exposed workers as well as to inform the public. The use of the new technologies could be an important help for the workers training. Virtual Reality Projects developed by Iberinco are: a) CIPRES: Interactive Calculations of Radiological Protection in a Simulation Environmental and, b) ACEWO: Workers Control Access to Nuclear Power Plants, virtual Reality could be directly applicable to several aspects related with Radiological Protection Training, for example. An application that workers could used to learn the main aspects of Radiological Protection related with: a) Physical concepts, b) Regulations, c) Use of protective clothing, d) Access into and exit out controlled areas, e) ALARA criterion. An examples is the project ACEWO. A training program based on Virtual Reality systems with simulations of procedures in which the operators could receive high doses. In this way, the operation time and dose could be minimised according to the ALARA criterion owing to the ability of repeating the exercise, or the work, as many times as be necessary, like project CIPRES. Iberinco has been developed an educational CD multimedia on nuclear energy and the protection measures foreseen in the emergency plans for the Spanish Civil Protection Agency, with the aim of being distributed to all the schools placed near a nuclear power plant. (Author) 4 refs

Setting up virtual private network

International Nuclear Information System (INIS)

Huang Hongmei; Zhang Chengjun

2003-01-01

Setting up virtual private network for business enterprise provides a low cost network foundation, increases enterprise's network function and enlarges its private scope. The text introduces virtual private network's principal, privileges and protocols that use in virtual private network. At last, this paper introduces several setting up virtual private network's technologies which based on LAN

Setting up virtual private network

International Nuclear Information System (INIS)

Huang Hongmei; Zhang Chengjun

2003-01-01

Setting up virtual private network for business enterprise provides a low cost network foundation, increases enterprise network function and enlarges its private scope. This text introduces virtual private network principal, privileges and protocols applied in virtual private network. At last, this paper introduces several setting up virtual private network technologies which is based on LAN

Virtuality and Reality in Science

International Nuclear Information System (INIS)

Cohen-Tannoudji, G.

1995-01-01

This book compiles eight contributions devoted to the topical question about the relation between virtuality and reality. In the theoretical frame of quantum and relativistic particle physics, the concept of virtuality is used according to its strict and precise meaning. In this context, particles are generally invented before their discovery. Some famous historical experiments which led to the postulation and then the discovery of new particles are mentioned. These examples are used to illustrate and to discuss the concept of virtuality as well as the physical reality of virtual processes. But, how can the concept of virtuality in other scientific fields be applied ? In order to answer this question, the concepts of virtuality and reality are discussed in other branches of physics as well as in other fields such as geophysics, cosmology and biology. Philosophical and sociological implications of virtual realities are also considered. Moreover, in relation to virtuality and reality, the connections between modeling, simulation and experimentation, their respective roles, the advantages and risks of their use are discussed (in relation to nuclear sciences and geophysical problems) (N.T.)

Optimizing Virtual Network Functions Placement in Virtual Data Center Infrastructure Using Machine Learning

Science.gov (United States)

Bolodurina, I. P.; Parfenov, D. I.

2018-01-01

We have elaborated a neural network model of virtual network flow identification based on the statistical properties of flows circulating in the network of the data center and characteristics that describe the content of packets transmitted through network objects. This enabled us to establish the optimal set of attributes to identify virtual network functions. We have established an algorithm for optimizing the placement of virtual data functions using the data obtained in our research. Our approach uses a hybrid method of visualization using virtual machines and containers, which enables to reduce the infrastructure load and the response time in the network of the virtual data center. The algorithmic solution is based on neural networks, which enables to scale it at any number of the network function copies.

Incorporating Virtually Immersive Environments as a Collaborative Medium for Virtual Teaming

Directory of Open Access Journals (Sweden)

Charles J. Lesko, Jr.

2012-08-01

Full Text Available Virtually immersive environments incorporate the use of various computer modelling and simulation techniques enabling geographically dispersed virtual project teams to interact within an artificially projected three-dimensional space online. This study focused on adoption of virtually immersive technologies as a collaborative media to support virtual teaming of both graduate and undergraduate-level project management students. The data and information from this study has implications for educators using virtually immersive environments in the classroom. In this study, we specifically evaluated two key components in this paper: 1 students’ level of trust and; 2 students’ willingness to use the technology, along with their belief about the virtual environment’s ability to extend and improve knowledge sharing in their team work environment. We learned that while students did find the environment a positive add on for working collaboratively, there were students who were neither more nor less likely to use the technology for future collaborative ventures. Most of the students who were not very positive about the environment were “fence sitters” likely indicating needs related to additional training to improve communication skills. Finally, based on the full study results we have provided basic recommendations designed to support team trust building in the system along with interpersonal trust building to facilitate knowledge transfer and better strategic us of the technology.

Real time determination of dose radiation through artificial intelligence and virtual reality; Determinacao de dose de radiacao, em tempo real, atraves de inteligencia artificial e realidade virtual

Energy Technology Data Exchange (ETDEWEB)

Freitas, Victor Goncalves Gloria

2009-07-01

In the last years, a virtual environment of Argonauta research reactor, sited in the Instituto de Engenharia Nuclear (Brazil), has been developed. Such environment, called here Argonauta Virtual (AV), is a 3D model of the reactor hall, in which virtual people (avatar) can navigate. In AV, simulations of nuclear sources and doses are possible. In a recent work, a real time monitoring system (RTMS) was developed to provide (by means of Ethernet TCP/I P) the information of area detectors situated in the reactor hall. Extending the scope of AV, this work is intended to provide a continuous determination of gamma radiation dose in the reactor hall, based in several monitored parameters. To accomplish that a module based in artificial neural network (ANN) was developed. The ANN module is able to predict gamma radiation doses using as inputs: the avatar position (from virtual environment), the reactor power (from RTMS) and information of fixed area detectors (from RTMS). The ANN training data has been obtained by measurements of gamma radiation doses in a mesh of points, with previously defined positions, for different power levels. Through the use of ANN it is possible to estimate, in real time, the dose received by a person at any position in Argonauta reactor hall. Such approach allows tasks simulations and training of people inside the AV system, without exposing them to radiation effects. (author)

Virtual Teaming and Collaboration Technology: A Study of Influences on Virtual Project Outcomes

Science.gov (United States)

Broils, Gary C.

2014-01-01

The purpose of this quantitative correlational study was to explore the relationships between the independent variables, contextual factors for virtual teams and collaboration technology, and the dependent variable, virtual project outcomes. The problem leading to the need for the study is a lower success rate for virtual projects compared to…

Drafting of the dismantling operations of the MAR 200 workshop with the help of virtual reality

International Nuclear Information System (INIS)

Chabal, C.; Soulabaille, Y.; Garnier, T.; Callixte, O.

2014-01-01

In order to optimize future dismantling operations of nuclear installations virtual reality allows the validation of predefined scenarios and their adequacy with the environment. CEA uses an immersion and interactive room to validate maintenance and dismantling operations. The equipment of this room is composed of a video wall that gives a 3-dimensional view of the virtual environment, and of a system for motion capture. For the simulation of handling operations a haptic interface has been designed, it allows the user to receive a tactic and effort-feeling feed back. The immersion is completed by a phonic ambience that creates sounds for virtual operations. The use of the immersion room for optimizing the dismantling of a spent fuel dissolver (MAR 200) used in hot cell is presented. (A.C.)

Interpretations of virtual reality.

Science.gov (United States)

Voiskounsky, Alexander

2011-01-01

University students were surveyed to learn what they know about virtual realities. The two studies were administered with a half-year interval in which the students (N=90, specializing either in mathematics and science, or in social science and humanities) were asked to name particular examples of virtual realities. The second, but not the first study, was administered after the participants had the chance to see the movie "Avatar" (no investigation was held into whether they really saw it). While the students in both studies widely believed that activities such as social networking and online gaming represent virtual realities, some other examples provided by the students in the two studies differ: in the second study the participants expressed a better understanding of the items related to virtual realities. At the same time, not a single participant reported particular psychological states (either regular or altered) as examples of virtual realities. Profound popularization efforts need to be done to acquaint the public, including college students, with virtual realities and let the public adequately understand how such systems work.

Virtual Dance and Motion-Capture

Directory of Open Access Journals (Sweden)

Marc Boucher

2011-01-01

Full Text Available A general view of various ways in which virtual dance can be understood is presented in the first part of this article. It then appraises the uses of the term “virtual” in previous studies of digital dance. A more in-depth view of virtual dance as it relates to motion-capture is offered, and key issues are discussed regarding computer animation, digital imaging, motion signature, virtual reality and interactivity. The paper proposes that some forms of virtual dance be defined in relation to both digital technologies and contemporary theories of virtuality.

Sense of presence and anxiety during virtual social interactions between a human and virtual humans.

Science.gov (United States)

Morina, Nexhmedin; Brinkman, Willem-Paul; Hartanto, Dwi; Emmelkamp, Paul M G

2014-01-01

Virtual reality exposure therapy (VRET) has been shown to be effective in treatment of anxiety disorders. Yet, there is lack of research on the extent to which interaction between the individual and virtual humans can be successfully implanted to increase levels of anxiety for therapeutic purposes. This proof-of-concept pilot study aimed at examining levels of the sense of presence and anxiety during exposure to virtual environments involving social interaction with virtual humans and using different virtual reality displays. A non-clinical sample of 38 participants was randomly assigned to either a head-mounted display (HMD) with motion tracker and sterescopic view condition or a one-screen projection-based virtual reality display condition. Participants in both conditions engaged in free speech dialogues with virtual humans controlled by research assistants. It was hypothesized that exposure to virtual social interactions will elicit moderate levels of sense of presence and anxiety in both groups. Further it was expected that participants in the HMD condition will report higher scores of sense of presence and anxiety than participants in the one-screen projection-based display condition. Results revealed that in both conditions virtual social interactions were associated with moderate levels of sense of presence and anxiety. Additionally, participants in the HMD condition reported significantly higher levels of presence than those in the one-screen projection-based display condition (p = .001). However, contrary to the expectations neither the average level of anxiety nor the highest level of anxiety during exposure to social virtual environments differed between the groups (p = .97 and p = .75, respectively). The findings suggest that virtual social interactions can be successfully applied in VRET to enhance sense of presence and anxiety. Furthermore, our results indicate that one-screen projection-based displays can successfully activate levels of anxiety in

Sense of presence and anxiety during virtual social interactions between a human and virtual humans

Directory of Open Access Journals (Sweden)

Nexhmedin Morina

2014-04-01

Full Text Available Virtual reality exposure therapy (VRET has been shown to be effective in treatment of anxiety disorders. Yet, there is lack of research on the extent to which interaction between the individual and virtual humans can be successfully implanted to increase levels of anxiety for therapeutic purposes. This proof-of-concept pilot study aimed at examining levels of the sense of presence and anxiety during exposure to virtual environments involving social interaction with virtual humans and using different virtual reality displays. A non-clinical sample of 38 participants was randomly assigned to either a head-mounted display (HMD with motion tracker and sterescopic view condition or a one-screen projection-based virtual reality display condition. Participants in both conditions engaged in free speech dialogues with virtual humans controlled by research assistants. It was hypothesized that exposure to virtual social interactions will elicit moderate levels of sense of presence and anxiety in both groups. Further it was expected that participants in the HMD condition will report higher scores of sense of presence and anxiety than participants in the one-screen projection-based display condition. Results revealed that in both conditions virtual social interactions were associated with moderate levels of sense of presence and anxiety. Additionally, participants in the HMD condition reported significantly higher levels of presence than those in the one-screen projection-based display condition (p = .001. However, contrary to the expectations neither the average level of anxiety nor the highest level of anxiety during exposure to social virtual environments differed between the groups (p = .97 and p = .75, respectively. The findings suggest that virtual social interactions can be successfully applied in VRET to enhance sense of presence and anxiety. Furthermore, our results indicate that one-screen projection-based displays can successfully activate levels

Reducing radiation exposures at nuclear power plants using virtual job planning

International Nuclear Information System (INIS)

Verzilov, Y.; Husain, A.

2014-01-01

Advanced Dose Exposure Planning Tool (ADEPT) is an innovative solution for assisting nuclear station staff to effectively minimize worker dose during inspection and maintenance activities and to improve ALARA job planning. ADEPT combines visualization and simulation of the radioactive environment at a nuclear station to estimate worker dose. It allows users to walk through a virtual job plan and receive a live radiation dose estimate for the planned work. (author)

Innovation and Virtual Environments: Towards Virtual Knowledge Brokers

OpenAIRE

VERONA G; PRANDELLI E.; SAWHNEY M.

2006-01-01

The authors examine the implications of virtual customer environments for supporting the innovation process. By building on the literature of knowledge brokers, they introduce the concept of virtual knowledge brokers — actors who leverage the internet to support third parties’ innovation activities. These actors enable firms to extend their reach in engaging with customers and they also allow firms to have a richer dialogue with customers because of their perceived neutrality. Consequently...

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' ...

Virtual Project Teams

DEFF Research Database (Denmark)

Bjørn, Pernille

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......, professional disciplines, time differences and technology. This thesis comprises a general introduction, referred to as the summary report, and seven research papers, which deal in detail with the results and findings of the empirical cases. The summary report provides a general introduction to the research......, 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...

Exploring Virtual Reality for Classroom Use: The Virtual Reality and Education Lab at East Carolina University.

Science.gov (United States)

Auld, Lawrence W. S.; Pantelidis, Veronica S.

1994-01-01

Describes the Virtual Reality and Education Lab (VREL) established at East Carolina University to study the implications of virtual reality for elementary and secondary education. Highlights include virtual reality software evaluation; hardware evaluation; computer-based curriculum objectives which could use virtual reality; and keeping current…

Virtual Machine Logbook - Enabling virtualization for ATLAS

International Nuclear Information System (INIS)

Yao Yushu; Calafiura, Paolo; Leggett, Charles; Poffet, Julien; Cavalli, Andrea; Frederic, Bapst

2010-01-01

ATLAS software has been developed mostly on CERN linux cluster lxplus or on similar facilities at the experiment Tier 1 centers. The fast rise of virtualization technology has the potential to change this model, turning every laptop or desktop into an ATLAS analysis platform. In the context of the CernVM project we are developing a suite of tools and CernVM plug-in extensions to promote the use of virtualization for ATLAS analysis and software development. The Virtual Machine Logbook (VML), in particular, is an application to organize work of physicists on multiple projects, logging their progress, and speeding up ''context switches'' from one project to another. An important feature of VML is the ability to share with a single 'click' the status of a given project with other colleagues. VML builds upon the save and restore capabilities of mainstream virtualization software like VMware, and provides a technology-independent client interface to them. A lot of emphasis in the design and implementation has gone into optimizing the save and restore process to makepractical to store many VML entries on a typical laptop disk or to share a VML entry over the network. At the same time, taking advantage of CernVM's plugin capabilities, we are extending the CernVM platform to help increase the usability of ATLAS software. For example, we added the ability to start the ATLAS event display on any computer running CernVM simply by clicking a button in a web browser. We want to integrate seamlessly VML with CernVM unique file system design to distribute efficiently ATLAS software on every physicist computer. The CernVM File System (CVMFS) download files on-demand via HTTP, and cache it locally for future use. This reduces by one order of magnitude the download sizes, making practical for a developer to work with multiple software releases on a virtual machine.

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....

A Virtual Commissioning Learning Platform

DEFF Research Database (Denmark)

Mortensen, Steffen; Madsen, Ole

2018-01-01

The introduction of reconfigurable manufacturing systems (RMS), Industry 4.0 and the associated technologies requires the establishment of new competencies. Towards that goal, Aalborg University (AAU) has developed an Industry 4.0 learning factory, the AAU Smart Production Lab. The AAU Smart...... Production Lab integrates a number of Industry 4.0 technologies for learning and research purposes. One of the many techniques is virtual commissioning. Virtual commissioning uses a virtual plant model and real controllers (PLCs) enabling a full emulation of the manufacturing system for verification. Virtual...... commissioning can lower the commissioning time up to 63%, allowing faster time to market. However, virtual commission is still missing industrial impact one of the reasons being lack of competencies and integration experiences. The paper presents the setup of the virtual commissioning learning platform...

Virtual toolbox

Science.gov (United States)

Jacobus, Charles J.; Jacobus, Heidi N.; Mitchell, Brian T.; Riggs, A. J.; Taylor, Mark J.

1993-04-01

At least three of the five senses must be fully addressed in a successful virtual reality (VR) system. Sight, sound, and touch are the most critical elements for the creation of the illusion of presence. Since humans depend so much on sight to collect information about their environment, this area has been the focus of much of the prior art in virtual reality, however, it is also crucial that we provide facilities for force, torque, and touch reflection, and sound replay and 3-D localization. In this paper we present a sampling of hardware and software in the virtual environment maker's `toolbox' which can support rapidly building up of customized VR systems. We provide demonstrative examples of how some of the tools work and we speculate about VR applications and future technology needs.

Influence of the absorptive part of the complex potential on the S-Matrix poles

International Nuclear Information System (INIS)

Grama, C.; Grama, N.; Zamfirescu, I

2001-01-01

Although the polology of the S-matrix has been extensively studied, it occurred that some aspects remained disputable in the case of complex central potential V(r)=gV(r), g in C . These aspects are related to the origin of the observed narrow Σ-hypernuclear states that have been interpreted by Gal, Toker and Alexander as states which correspond to S-matrix poles situated in the second k-plane quadrant. From the analytical properties of the S-matrix for a real potential it results that there is no pole in the first and second k-plane quadrants, except for the imaginary k-axis. By switching on the absorption the S-matrix poles for real potential can evolve into the second quadrant of the k-plane. A critical study of the Σ-hypernuclear states needs the analysis of the motion of the S-matrix poles in the k-plane for variable complex coupling strength g. Recently contradictory opinions relative to the S-matrix poles trajectories in the complex k-plane for a complex square potential occurred. According to some authors the poles in the second quadrant can occur either from bound state poles moving anticlockwise, or from virtual state poles and capture resonant state poles moving clockwise as the absorption is switched on. Dabrowski argues that the statement made by Gal et al, Bonetti et al and Oset et al concerning the movement of the virtual poles with increasing absorptive potential is in general not correct. Dabrowski relates the direction in which the pole moves when the potential absorption increases to the direction in which the pole moves with increasing the real part of the potential, without clarifying this last question. For example, two poles moving in opposite directions along the imaginary k-axis are associated by Dabrowski to the same state. This is a wrong result, because one should associate a single pole to each quantum state. The aim of our work is to study the influence of the absorptive part of the potential on the S-matrix poles for the non

A Virtual History of Mauritius

African Journals Online (AJOL)

admpather

University of Mauritius, Réduit, Mauritius. 116. A Virtual History ... out will be presented. Keywords: Virtual Heritage, Virtual Reality, Archaeology, Mauritius ... money would better be spent on other major education and IT development projects ...

Effects of VIrtualIty on Employee Performance and CommItment: A Research

OpenAIRE

Baysal, Zeynep; Baraz, Barış

2017-01-01

In the modern business world, due to the impact of technological advancements and globalisation,organisations are obliged to keep up with the change in order to seize new opportunities they encounterand overcome the obstacles in their way. Concepts of virtuality and virtual organisations are amongthese concepts which surfaced as a result of these changes. All white-collar employees have a certaindegree of virtuality and the fact that organisations are taking rapid steps towards virtualisation...

The value of virtual touch tissue image (VTI) and virtual touch tissue quantification (VTQ) in the differential diagnosis of thyroid nodules

International Nuclear Information System (INIS)

Zhang, Feng-Juan; Han, Ruo-Ling; Zhao, Xin-Ming

2014-01-01

Highlights: • All nodules in the research were confirmed by histopathology. • The classification method of VTI was easy to learn. • VTQ could provide quantitative elasticity measurements for thyroid nodules. • VTI classification could provide semi-quantitative elasticity analysis. • The area ratio could show invasive extent of malignant tumor. - Abstract: Objectives: To explore the value of virtual touch tissue image (VTI) and virtual touch tissue quantification (VTQ) in the differential diagnosis of thyroid nodules. Methods: One-hundred and seven patients with 113 thyroid nodules were performed conventional ultrasound and acoustic radiation force impulse (ARFI) elastography. The stiffness of the nodules on virtual touch tissue image (VTI) was graded, and the area ratios (AR) of nodules on VTI images versus on B-mode images were calculated. Shear wave velocity (SWV) within the thyroid nodules were measured using virtual touch tissue quantification (VTQ) technique. The pathological diagnosis as the gold standard draws the receiver-operating characteristic curve (ROC) to find the cut-off point of VTI grades, AR and SWV to predict thyroid cancer. Results: The difference in VTI grades of malignant and benign nodules was statistically significant (P < 0.05), as well as in AR and SWV. There was no significant difference in the AR of nodules or the SWV of nodules in benign group or in malignant group. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of VTI grades, AR, and SWV in the differential diagnosis of thyroid nodules were calculated. There was no significant difference in diagnostic accuracy among the three methods. Conclusion: VTI grades, AR of nodules on VTI images versus on B-mode images and SWV within the nodules can help the differential diagnosis of thyroid nodules

Virtual reality for employability skills

OpenAIRE

Minocha, Shailey; Tudor, Ana-Despina

2017-01-01

We showed a variety of virtual reality technologies, and through examples, we discussed how virtual reality technology is transforming work styles and workplaces. Virtual reality is becoming pervasive in almost all domains starting from arts, environmental causes to medical education and disaster management training, and to supporting patients with Dementia. Thus, an awareness of the virtual reality technology and its integration in curriculum design will provide and enhance employability ski...

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....

Real and virtual radiation

International Nuclear Information System (INIS)

Wolynec, E.

1988-01-01

Electrodisintegration cross sections related to the corresponding photonuclear process through virtual-photon spectra. A brief review of virtual-photon theory is presented. Calculations of DWBA virtual-photon spectra for finite nuclei are compared with experimental results. The multipole decomposition of electrodisintegration cross sections using these spectra is discussed and several experimental results are presented. A brief review for the bremsstrahlung cross section is also presented. (author) [pt

Virtual organization of hospital medical imaging: a user satisfaction survey.

Science.gov (United States)

Sicotte, Claude; Paré, Guy; Bini, Kobena Kra; Moreault, Marie-Pierre; Laverdure, Guy

2010-12-01

A virtual medical imaging department is an innovative and demanding organizational model, to the extent that the underlying goal is to achieve a continuous and advanced organizational integration of human and physical resources, clinical data, and clienteles. To better understand the kind of benefits offered, we conducted a survey of three groups of users--radiologists, radiological technologists, and medical specialists--working in a five-site virtual organization. We received 127 valid questionnaires, for an overall response rate of 66%. The assessments vary according to the use made of the system. The scores for system quality and the quality of the data produced were markedly higher for intra-hospital use (respectively 7.9 and 8.7 out of 10) than for inter-hospital use (5.4 and 7.0). Despite the negative assessments they made of inter-hospital use, users maintained a positive attitude toward some type of virtual organization of medical imaging. Indeed, the score for Overall satisfaction with the system was very high, 8.9 out of 10. Moreover, the scores for Intended future use of the system were very high for both intra-hospital use (8.9) and inter-hospital use (8.7). We also found significant differences in perceptions among user groups.

Pilot study on virtual imaging for patient information on radiotherapy planning and delivery

International Nuclear Information System (INIS)

Sulé-Suso, J.; Finney, S.; Bisson, J.; Hammersley, S.; Jassel, S.; Knight, R.; Hicks, C.; Sargeant, S.; Lam, K.-P.; Belcher, J.; Collins, D.; Bhana, R.; Adab, F.; O'Donovan, C.; Moloney, A.

2015-01-01

It is widely accepted that health professionals might sometimes underestimate cancer patients' needs for information on the complex process of radiotherapy (RT) planning and delivery. Furthermore, relatives might also feel excluded from the treatment of their loved ones. This pilot study was carried out in order to assess whether both patients and their relatives would welcome further information on RT planning and delivery using the virtual reality (VR) system VERT. One hundred and fifty patients with different types of cancer receiving radical RT were included in the study. Patients and relatives were shown using VERT on a one-to-one basis with an oncologist or a radiographer, a standard room where RT is given, a linear accelerator, and how RT is planned and delivered using their own planning CT Scans. Patients welcomed this information as it helped them to reduce their fears about RT. Relatives felt also more involved in the treatment of their loved one. The results obtained in this pilot study show that VR aids could become an important tool for delivering information on RT to both patients and relatives. - Highlights: • Virtual imaging helps patients to better understand RT planning and delivery. • Virtual imaging reduces the fear factor. • Virtual imaging improves patients and relatives satisfaction

Varieties of virtualization

Science.gov (United States)

Ellis, Stephen R.

1991-01-01

Natural environments have a content, i.e., the objects in them; a geometry, i.e., a pattern of rules for positioning and displacing the objects; and a dynamics, i.e., a system of rules describing the effects of forces acting on the objects. Human interaction with most common natural environments has been optimized by centuries of evolution. Virtual environments created through the human-computer interface similarly have a content, geometry, and dynamics, but the arbitrary character of the computer simulation creating them does not insure that human interaction with these virtual environments will be natural. The interaction, indeed, could be supernatural but it also could be impossible. An important determinant of the comprehensibility of a virtual environment is the correspondence between the environmental frames of reference and those associated with the control of environmental objects. The effects of rotation and displacement of control frames of reference with respect to corresponding environmental references differ depending upon whether perceptual judgement or manual tracking performance is measured. The perceptual effects of frame of reference displacement may be analyzed in terms of distortions in the process of virtualizing the synthetic environment space. The effects of frame of reference displacement and rotation have been studied by asking subjects to estimate exocentric direction in a virtual space.

Current steering and current focusing in cochlear implants: comparison of monopolar, tripolar, and virtual channel electrode configurations.

NARCIS (Netherlands)

Berenstein, C.K.; Mens, L.H.M.; Mulder, J.J.S.; Vanpoucke, F.J.

2008-01-01

OBJECTIVES: To compare the effects of Monopole (Mono), Tripole (Tri), and "Virtual channel" (Vchan) electrode configurations on spectral resolution and speech perception in a crossover design. DESIGN: Nine experienced adults who received an Advanced Bionics CII/90K cochlear implant participated in a

Cooperation, Coordination, and Trust in Virtual Teams: Insights from Virtual Games

Science.gov (United States)

Korsgaard, M. Audrey; Picot, Arnold; Wigand, Rolf T.; Welpe, Isabelle M.; Assmann, Jakob J.

This chapter considers fundamental concepts of effective virtual teams, illustrated by research on Travian, a massively multiplayer online strategy game wherein players seek to build empires. Team inputs are the resources that enable individuals to work interdependently toward a common goal, including individual and collective capabilities, shared knowledge structures, and leadership style. Team processes, notably coordination and cooperation, transform team inputs to desired collective outcomes. Because the members of virtual teams are geographically dispersed, relying on information and communication technology, three theories are especially relevant for understanding how they can function effectively: social presence theory, media richness theory, and media synchronicity theory. Research in settings like Travian can inform our understanding of structures, processes, and performance of virtual teams. Such research could provide valuable insight into the emergence and persistence of trust and cooperation, as well as the impact of different communication media for coordination and information management in virtual organizations.

ROLE OF VIRTUALIZATION IN CLOUD COMPUTING

OpenAIRE

Avneet kaur; Dr. Gaurav Gupta; Dr. Gurjit Singh Bhathal

2017-01-01

Cloud Computing is the fundamental change happening in the field of Information Technology.. Virtualization is the key component of cloud computing. With the use of virtualization, cloud computing brings about not only convenience and efficiency benefits, but also great challenges in the field of data security and privacy protection. .In this paper, we are discussing about virtualization, architecture of virtualization technology as well as Virtual Machine Monitor (VMM). Further discussing ab...

First virtual endocasts of adapiform primates.

Science.gov (United States)

Harrington, Arianna R; Silcox, Mary T; Yapuncich, Gabriel S; Boyer, Doug M; Bloch, Jonathan I

2016-10-01

Well-preserved crania of notharctine adapiforms from the Eocene of North America provide the best direct evidence available for inferring neuroanatomy and encephalization in early euprimates (crown primates). Virtual endocasts of the notharctines Notharctus tenebrosus (n = 3) and Smilodectes gracilis (n = 4) from the middle Eocene Bridger formation of Wyoming, and the late Eocene European adapid adapiform Adapis parisiensis (n = 1), were reconstructed from high-resolution X-ray computed tomography (CT) data. While the three species share many neuroanatomical similarities differentiating them from plesiadapiforms (stem primates) and extant euprimates, our sample of N. tenebrosus displays more variation than that of S. gracilis, possibly related to differences in the patterns of cranial sexual dimorphism or within-lineage evolution. Body masses predicted from associated teeth suggest that N. tenebrosus was larger and had a lower encephalization quotient (EQ) than S. gracilis, despite their close relationship and similar inferred ecologies. Meanwhile, body masses predicted from cranial length of the same specimens suggest that the two species were more similar, with overlapping body mass and EQ, although S. gracilis exhibits a range of EQs shifted upwards relative to that of N. tenebrosus. While associated data from other parts of the skeleton are mostly lacking for specimens included in this study, measurements for unassociated postcrania attributed to these species yield body mass and EQ estimates that are also more similar to each other than those based on teeth. Regardless of the body mass prediction method used, results suggest that the average EQ of adapiforms was similar to that of plesiadapiforms, only overlapped the lower quadrant for the range of extant strepsirrhines, and did not overlap with the range of extant haplorhines. However, structural changes evident in these endocasts suggest that early euprimates relied more on vision than olfaction

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...... the performance of specific home care services by means of video conversations rather than physical visits in the citizens’ homes. As scholars within the STS tradition maintain, technologies do not simply replace a human function; they rather transform care work, redistributing tasks between citizens, technology...... 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....

Real time determination of dose radiation through artificial intelligence and virtual reality

International Nuclear Information System (INIS)

Freitas, Victor G.G.; Mol, Antonio C.A.; Pereira, Claudio M.N.A.

2009-01-01

In the last years, a virtual environment of Argonauta research reactor, sited in the Instituto de Engenharia Nuclear (Brazil), has been developed. Such environment, called here Argonauta Virtual (AV), is a 3D model of the reactor hall, in which virtual people (avatar) can navigate. In AV, simulations of nuclear sources and doses are possible. In a recent work, a real time monitoring system (RTMS) was developed to provide (by means of Ethernet TCP/IP) the information of area detectors situated in the reactor hall. Extending the scope of AV, this work is intended to provide a continuous determination of gamma radiation dose in the reactor hall, based in several monitored parameters. To accomplish that a module based in artificial neural network (ANN) was developed. The ANN module is able to predict gamma radiation doses using as inputs: the avatar position (from virtual environment), the reactor power (from RTMS) and information of fixed area detectors (from RTMS). The ANN training data has been obtained by measurements of gamma radiation doses in a mesh of points, with previously defined positions, for different power levels. Through the use of ANN it is possible to estimate, in real time, the dose received by a person at any position in Argonauta reactor hall. Such approach allows tasks simulations and training of people inside the AV system, without exposing them to radiation effects. (author)

Real time determination of dose radiation through artificial intelligence and virtual reality

International Nuclear Information System (INIS)

Freitas, Victor Goncalves Gloria

2009-01-01

In the last years, a virtual environment of Argonauta research reactor, sited in the Instituto de Engenharia Nuclear (Brazil), has been developed. Such environment, called here Argonauta Virtual (AV), is a 3D model of the reactor hall, in which virtual people (avatar) can navigate. In AV, simulations of nuclear sources and doses are possible. In a recent work, a real time monitoring system (RTMS) was developed to provide (by means of Ethernet TCP/I P) the information of area detectors situated in the reactor hall. Extending the scope of AV, this work is intended to provide a continuous determination of gamma radiation dose in the reactor hall, based in several monitored parameters. To accomplish that a module based in artificial neural network (ANN) was developed. The ANN module is able to predict gamma radiation doses using as inputs: the avatar position (from virtual environment), the reactor power (from RTMS) and information of fixed area detectors (from RTMS). The ANN training data has been obtained by measurements of gamma radiation doses in a mesh of points, with previously defined positions, for different power levels. Through the use of ANN it is possible to estimate, in real time, the dose received by a person at any position in Argonauta reactor hall. Such approach allows tasks simulations and training of people inside the AV system, without exposing them to radiation effects. (author)

Effects of a virtual reality-based exercise program on functional recovery in stroke patients: part 1.

Science.gov (United States)

Lee, Kyoung-Hee

2015-06-01

This study aimed to determine the effects of a virtual reality exercise program using the Interactive Rehabilitation and Exercise System (IREX) on the recovery of motor and cognitive function and the performance of activities of daily living in stroke patients. [Subjects] The study enrolled 10 patients diagnosed with stroke who received occupational therapy at the Department of Rehabilitation Medicine of Hospital A between January and March 2014. [Methods] The patients took part in the virtual reality exercise program for 30 minutes each day, three times per week, for 4 weeks. Then, the patients were re-evaluated to determine changes in upper extremity function, cognitive function, and performance of activities of daily living 4 weeks after the baseline assessment. [Results] In the experimental group, there were significant differences in the Korea-Mini Mental Status Evaluation, Korean version of the modified Barthel index, and Fugl-Meyer assessment scores between the baseline and endpoint. [Conclusion] The virtual reality exercise program was effective for restoring function in stroke patients. Further studies should develop systematic protocols for rehabilitation training with a virtual reality exercise program.

Additional Virtual Reality Sitting Balance Training Using XBox Kinect™ in Patients with Neurological Disorders: A Pilot Study

Directory of Open Access Journals (Sweden)

Xina Henry Quadros

2017-10-01

Full Text Available Introduction: Sitting balance is a prerequisite to upper extremity function, standing and walking, which is affected in various neurological diseases. It is important to attain a good level of sitting balance before one can proceed to standing. In recent years, virtual reality game training has gained a widespread application. Aim: This pilot study aimed to examine the role of additional virtual reality sitting balance training using a commercial interactive virtual reality system- Xbox Kinect™ in patients with neurological disorders. Materials and Methods: Four patients with sitting balance impairments following neurological disorders received two weeks of virtual reality based therapy along with the conventional physiotherapy. Sitting balance was evaluated using FIST (Function In Sitting Test scores at baseline, one week and after two weeks of intervention. Results: All four patients showed clinically significant improvement in FIST score between the pre and post intervention. Percentage of improvement in FIST score was approximately 27% with a minimum change of 10 points in the FIST score Minimal Clinically Important Difference (MCID=6.5. Conclusion: Additional virtual reality training may improve sitting balance control in neurological patients with balance impairments. It can be used as an adjunct in routine neurorehabilitation.

Virtual rehabilitation in a school setting: is it feasible for children with cerebral palsy?

Science.gov (United States)

Rosie, Juliet A; Ruhen, Shelley; Hing, Wayne A; Lewis, Gwyn N

2015-01-01

To determine the feasibility of a school-based virtual rehabilitation intervention for children with cerebral palsy. A feasibility study was conducted using a mixed method approach. Participants were five children with cerebral palsy who were currently attending a rural school. Each child received an 8-week rehabilitation programme involving an Interactive Virtual Reality Exercise (IREX) system. The IREX was placed in the child's school for the duration of the intervention. Each child's programme was designed by a physiotherapist but supervised by a teacher aide at the school. Feasibility of the intervention was assessed through a questionnaire completed by the child and an interview conducted with the teacher supervisor. The children all rated the IREX intervention as fun, easy to use, and beneficial for their arm. Categories from the supervisor interviews centred on resolving technical issues, the enjoyment of taking part due to the child's progress, and the central role of interacting with the child. Input from the research physiotherapist was critical to the success of the intervention. The IREX is feasible to implement in a school-based setting supervised by teachers. This provides an option for delivering physiotherapy to children in isolated areas who do not receive on-going therapy. Implication for Rehabilitation Virtual rehabilitation programmes using the IREX are feasible in a school-based setting. The negative impact of technical difficulties is likely to be overcome by the user's enjoyment and rehabilitation benefits gained. Input from a therapist in designing and monitoring the programme is critical.

A virtual experimenter to increase standardization for the investigation of placebo effects

Directory of Open Access Journals (Sweden)

Bjoern Horing

2016-07-01

Full Text Available Abstract Background Placebo effects are mediated by expectancy, which is highly influenced by psychosocial factors of a treatment context. These factors are difficult to standardize. Furthermore, dedicated placebo research often necessitates single-blind deceptive designs where biases are easily introduced. We propose a study protocol employing a virtual experimenter – a computer program designed to deliver treatment and instructions – for the purpose of standardization and reduction of biases when investigating placebo effects. Methods To evaluate the virtual experimenter’s efficacy in inducing placebo effects via expectancy manipulation, we suggest a partially blinded, deceptive design with a baseline/retest pain protocol (hand immersions in hot water bath. Between immersions, participants will receive an (actually inert medication. Instructions pertaining to the medication will be delivered by one of three metaphors: The virtual experimenter, a human experimenter, and an audio/text presentation (predictor “Metaphor”. The second predictor includes falsely informing participants that the medication is an effective pain killer, or correctly informing them that it is, in fact, inert (predictor “Instruction”. Analysis will be performed with hierarchical linear modelling, with a sample size of N = 50. Results from two pilot studies are presented that indicate the viability of the pain protocol (N = 33, and of the virtual experimenter software and placebo manipulation (N = 48. Discussion It will be challenging to establish full comparability between all metaphors used for instruction delivery, and to account for participant differences in acceptance of their virtual interaction partner. Once established, the presence of placebo effects would suggest that the virtual experimenter exhibits sufficient cues to be perceived as a social agent. He could consequently provide a convenient platform to investigate effects of

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.

Effectiveness of conventional versus virtual reality-based balance exercises in vestibular rehabilitation for unilateral peripheral vestibular loss: results of a randomized controlled trial.

Science.gov (United States)

Meldrum, Dara; Herdman, Susan; Vance, Roisin; Murray, Deirdre; Malone, Kareena; Duffy, Douglas; Glennon, Aine; McConn-Walsh, Rory

2015-07-01

To compare the effectiveness of virtual reality-based balance exercises to conventional balance exercises during vestibular rehabilitation in patients with unilateral peripheral vestibular loss (UVL). Assessor-blind, randomized controlled trial. Two acute care university teaching hospitals. Patients with UVL (N=71) who had dizziness/vertigo, and gait and balance impairment. Patients with UVL were randomly assigned to receive 6 weeks of either conventional (n=36) or virtual reality-based (n=35) balance exercises during vestibular rehabilitation. The virtual reality-based group received an off-the-shelf virtual reality gaming system for home exercise, and the conventional group received a foam balance mat. Treatment comprised weekly visits to a physiotherapist and a daily home exercise program. The primary outcome was self-preferred gait speed. Secondary outcomes included other gait parameters and tasks, Sensory Organization Test (SOT), dynamic visual acuity, Hospital Anxiety and Depression Scale, Vestibular Rehabilitation Benefits Questionnaire, and Activities Balance Confidence Questionnaire. The subjective experience of vestibular rehabilitation was measured with a questionnaire. Both groups improved, but there were no significant differences in gait speed between the groups postintervention (mean difference, -.03m/s; 95% confidence interval [CI], -.09 to .02m/s). There were also no significant differences between the groups in SOT scores (mean difference, .82%; 95% CI, -5.00% to 6.63%) or on any of the other secondary outcomes (P>.05). In both groups, adherence to exercise was high (∼77%), but the virtual reality-based group reported significantly more enjoyment (P=.001), less difficulty with (P=.009) and less tiredness after (P=.03) balance exercises. At 6 months, there were no significant between-group differences in physical outcomes. Virtual reality-based balance exercises performed during vestibular rehabilitation were not superior to conventional balance

APLIKASI SERVER VIRTUAL IP UNTUK MIKROKONTROLER

OpenAIRE

Ashari, Ahmad

2008-01-01

Selama ini mikrokontroler yang terhubung ke satu komputer hanya dapat diakses melalui satu IP saja, padahal kebanyakan sistem operasi sekarang dapat memperjanjikan lebih dari satu IP untuk setiap komputer dalam bentuk virtual IP. Penelitian ini mengkaji pemanfaatan virtual IP dari IP aliasing pada sistem operasi Linux sebagai Server Virtual IP untuk mikrokontroler. Prinsip dasar Server Virtual IP adalah pembuatan Virtual Host pada masing-masing IP untuk memproses paket-paket data dan menerjem...

Security challenges for virtualization in cloud

International Nuclear Information System (INIS)

Tayab, A.

2015-01-01

Virtualization is a model that is vastly growing in IT industry. Virtualization provides more than one logical resource in one single physical machine. Infrastructure use cloud services and on behalf of virtualization, cloud computing is also a rapidly growing model of IT industry. Cloud provider and cloud user, both remain ignorant of each other's security. Since virtualization and cloud computing are rapidly expanding and becoming more and more complex in infrastructure, more security is required to protect them from potential attacks and security threats. Virtualization provides various benefits in terms of hardware utilization, resources protection, remote access and other resources. This paper intends to discuss the common exploits of security uses in the virtualized environment and focuses on the security threats from the attacker's perspective. This paper discuss the major areas of virtualized model environment and also address the security concerns. And finally presents a solution for secure valorization in IT infrastructure and to protect inter communication of virtual machines. (author)

Talking with a Virtual Human : Controlling the Human Experience and Behavior in a Virtual Conversation

NARCIS (Netherlands)

Qu, C.

2014-01-01

Virtual humans are often designed to replace real humans in virtual reality applications for e.g., psychotherapy, education and entertainment. In general, applications with virtual humans are created for modifying a person's knowledge, beliefs, attitudes, emotions or behaviors. Reaching these

Characterization of a quadrant diamond transmission X-ray detector including a precise determination of the mean electron-hole pair creation energy.

Science.gov (United States)

Keister, Jeffrey W; Cibik, Levent; Schreiber, Swenja; Krumrey, Michael

2018-03-01

Precise monitoring of the incoming photon flux is crucial for many experiments using synchrotron radiation. For photon energies above a few keV, thin semiconductor photodiodes can be operated in transmission for this purpose. Diamond is a particularly attractive material as a result of its low absorption. The responsivity of a state-of-the art diamond quadrant transmission detector has been determined, with relative uncertainties below 1% by direct calibration against an electrical substitution radiometer. From these data and the measured transmittance, the thickness of the involved layers as well as the mean electron-hole pair creation energy were determined, the latter with an unprecedented relative uncertainty of 1%. The linearity and X-ray scattering properties of the device are also described.

Comparing two methods of education (virtual versus traditional) on learning of Iranian dental students: a post-test only design study.

Science.gov (United States)

Moazami, Fariborz; Bahrampour, Ehsan; Azar, Mohammad Reza; Jahedi, Farzad; Moattari, Marzieh

2014-03-05

The importance of using technologies such as e-learning in different disciplines is discussed in the literature. Researchers have measured the effectiveness of e-learning in a number of fields.Considering the lack of research on the effectiveness of online learning in dental education particularly in Iran, the advantages of these learning methods and the positive university atmosphere regarding the use of online learning. This study, therefore, aims to compare the effects of two methods of teaching (virtual versus traditional) on student learning. This post-test only design study approached 40, fifth year dental students of Shiraz University of Medical Sciences. From this group, 35 students agreed to participate. These students were randomly allocated into two groups, experimental (virtual learning) and comparison (traditional learning). To ensure similarity between groups, we compared GPAs of all participants by the Mann-Whitney U test (P > 0.05). The experimental group received a virtual learning environment courseware package specifically designed for this study, whereas the control group received the same module structured in a traditional lecture form. The virtual learning environment consisted of online and offline materials. Two identical valid, reliable post-tests that consisted of 40 multiple choice questions (MCQs) and 4 essay questions were administered immediately (15 min) after the last session and two months later to assess for knowledge retention. Data were analyzed by SPSS version 20. A comparison of the mean knowledge score of both groups showed that virtual learning was more effective than traditional learning (effect size = 0.69). The newly designed virtual learning package is feasible and will result in more effective learning in comparison with lecture-based training. However further studies are needed to generalize the findings of this study.

International virtual teams engineering global success

CERN Document Server

Brewer, P

2015-01-01

As a complete guide to international virtual team communication with practical problem-solving strategies, this book is a must read for managers and engineers in all stages of their professional development This book provides essential information for creating and maintaining successful international virtual teams for those who manage, participate in, or train others in international virtual teaming. Based on new studies in engineering communication, this book presents processes and principles that can help managers and engineers establish global virtual teams that work, assess the virtual team climate, and maintain the effectiveness of virtual teams across cultural boundaries. It provides knowledge and tools necessary to understand the variable contexts of global virtual teams, so that organizations are able to respond to inevitable changes in technology and the global marketplace.

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.

Software for virtual accelerator designing

International Nuclear Information System (INIS)

Kulabukhova, N.; Ivanov, A.; Korkhov, V.; Lazarev, A.

2012-01-01

The article discusses appropriate technologies for software implementation of the Virtual Accelerator. The Virtual Accelerator is considered as a set of services and tools enabling transparent execution of computational software for modeling beam dynamics in accelerators on distributed computing resources. Distributed storage and information processing facilities utilized by the Virtual Accelerator make use of the Service-Oriented Architecture (SOA) according to a cloud computing paradigm. Control system tool-kits (such as EPICS, TANGO), computing modules (including high-performance computing), realization of the GUI with existing frameworks and visualization of the data are discussed in the paper. The presented research consists of software analysis for realization of interaction between all levels of the Virtual Accelerator and some samples of middle-ware implementation. A set of the servers and clusters at St.-Petersburg State University form the infrastructure of the computing environment for Virtual Accelerator design. Usage of component-oriented technology for realization of Virtual Accelerator levels interaction is proposed. The article concludes with an overview and substantiation of a choice of technologies that will be used for design and implementation of the Virtual Accelerator. (authors)

Virtual currencies : Real opportunities?

OpenAIRE

Selldahl, Sara

2013-01-01

AbstractThe European Central Bank defines virtual currencies as ”unregulated, digital money, which is issued and usuallycontrolled by its developers, and used and accepted among the members of a specific virtual community.”(European Central Bank, 2012, p. 5) The interest in virtual currencies has increased immensely over the last fewyears as they become increasingly prevalent in our society across many different industries. Up until now, the field ofvirtual currencies has been mainly uncharte...

Corporate Training in Virtual Worlds

Directory of Open Access Journals (Sweden)

Charles Nebolsky

2004-12-01

Full Text Available This paper presents virtual training worlds that are relatively low-cost distributed collaborative learning environments suitable for corporate training. A virtual training world allows a facilitator, experts and trainees communicating and acting in the virtual environment for practicing skills during collaborative problem solving. Using these environments is beneficial to both trainees and corporations. Two system prototypes – the sales training and the leadership training virtual worlds – are described. The leadership training course design is discussed in details.

Task performance in virtual environments used for cognitive rehabilitation after traumatic brain injury.

Science.gov (United States)

Christiansen, C; Abreu, B; Ottenbacher, K; Huffman, K; Masel, B; Culpepper, R

1998-08-01

This report describes a reliability study using a prototype computer-simulated virtual environment to assess basic daily living skills in a sample of persons with traumatic brain injury (TBI). The benefits of using virtual reality in training for situations where safety is a factor have been established in defense and industry, but have not been demonstrated in rehabilitation. Thirty subjects with TBI receiving comprehensive rehabilitation services at a residential facility. An immersive virtual kitchen was developed in which a meal preparation task involving multiple steps could be performed. The prototype was tested using subjects who completed the task twice within 7 days. The stability of performance was estimated using intraclass correlation coefficients (ICCs). The ICC value for total performance based on all steps involved in the meal preparation task was .73. When three items with low variance were removed the ICC improved to .81. Little evidence of vestibular optical side-effects was noted in the subjects tested. Adequate initial reliability exists to continue development of the environment as an assessment and training prototype for persons with brain injury.

Sense of presence and anxiety during virtual social interactions between a human and virtual humans

OpenAIRE

Morina, Nexhmedin; Brinkman, Willem-Paul; Hartanto, Dwi; Emmelkamp, Paul M.G.

2014-01-01

Virtual reality exposure therapy (VRET) has been shown to be effective in treatment of anxiety disorders. Yet, there is lack of research on the extent to which interaction between the individual and virtual humans can be successfully implanted to increase levels of anxiety for therapeutic purposes. This proof-of-concept pilot study aimed at examining levels of the sense of presence and anxiety during exposure to virtual environments involving social interaction with virtual humans and using d...

Development of a dose database in the refuelling scenario of a nuclear power plant for a virtual reality application

International Nuclear Information System (INIS)

Rodenas, J.; Zarza, I.; Pascual, A.; Felipe, A.; Sanchez-Mayoral, M.L.

2002-01-01

Operators in Nuclear Power Plants can receive high doses during refuelling operation. A training program simulating refuelling operations will be useful to reduce doses received by workers as well as to minimise operation time. With this goal in mind a Virtual Reality application is developed in the frame of CIPRES Project (Calculos Interactivos de Proteccion Radiologica en un Entorno de Simulacion - Interactive Calculations of Radiological Protection in a Simulation Environment), a RD project sponsored by IBERINCO and developed jointly by IBERINCO and the Nuclear Engineering Department of the Polytechnic University of Valencia. The Virtual Reality application requires the possibility of displaying doses, both instantaneous and accumulated, at all times during the operator training. Therefore, it is necessary to elaborate a database containing dose rates at every point of the refuelling plant. This database is elaborated from Radiological Protection Surveillance data measured throughout the plant during refuelling operation. To estimate doses throughout the refuelling plant some interpolation routines have been used. Different assumptions have been adopted in order to perform the interpolation and obtain consistent data. In this paper, procedures developed to elaborate the dose database for the Virtual Reality application are presented and analysed

State Virtual Libraries

Science.gov (United States)

Pappas, Marjorie L.

2003-01-01

Virtual library? Electronic library? Digital library? Online information network? These all apply to the growing number of Web-based resource collections managed by consortiums of state library entities. Some, like "INFOhio" and "KYVL" ("Kentucky Virtual Library"), have been available for a few years, but others are just starting. Searching for…

CEDS Addresses: Virtual and Blended Learning

Science.gov (United States)

US Department of Education, 2015

2015-01-01

The Common Education Data Standards (CEDS) common data vocabulary supports the collection and use of information about virtual and blended learning. The data element "Virtual Indicator", introduced in version 3 of CEDS, supports a range of virtual learning-related use cases. The Virtual Indicator element may be related to a Course…

Sensorimotor Learning during a Marksmanship Task in Immersive Virtual Reality

Directory of Open Access Journals (Sweden)

Hrishikesh M. Rao

2018-02-01

Full Text Available Sensorimotor learning refers to improvements that occur through practice in the performance of sensory-guided motor behaviors. Leveraging novel technical capabilities of an immersive virtual environment, we probed the component kinematic processes that mediate sensorimotor learning. Twenty naïve subjects performed a simulated marksmanship task modeled after Olympic Trap Shooting standards. We measured movement kinematics and shooting performance as participants practiced 350 trials while receiving trial-by-trial feedback about shooting success. Spatiotemporal analysis of motion tracking elucidated the ballistic and refinement phases of hand movements. We found systematic changes in movement kinematics that accompanied improvements in shot accuracy during training, though reaction and response times did not change over blocks. In particular, we observed longer, slower, and more precise ballistic movements that replaced effort spent on corrections and refinement. Collectively, these results leverage developments in immersive virtual reality technology to quantify and compare the kinematics of movement during early learning of full-body sensorimotor orienting.

Sensorimotor Learning during a Marksmanship Task in Immersive Virtual Reality.

Science.gov (United States)

Rao, Hrishikesh M; Khanna, Rajan; Zielinski, David J; Lu, Yvonne; Clements, Jillian M; Potter, Nicholas D; Sommer, Marc A; Kopper, Regis; Appelbaum, Lawrence G

2018-01-01

Sensorimotor learning refers to improvements that occur through practice in the performance of sensory-guided motor behaviors. Leveraging novel technical capabilities of an immersive virtual environment, we probed the component kinematic processes that mediate sensorimotor learning. Twenty naïve subjects performed a simulated marksmanship task modeled after Olympic Trap Shooting standards. We measured movement kinematics and shooting performance as participants practiced 350 trials while receiving trial-by-trial feedback about shooting success. Spatiotemporal analysis of motion tracking elucidated the ballistic and refinement phases of hand movements. We found systematic changes in movement kinematics that accompanied improvements in shot accuracy during training, though reaction and response times did not change over blocks. In particular, we observed longer, slower, and more precise ballistic movements that replaced effort spent on corrections and refinement. Collectively, these results leverage developments in immersive virtual reality technology to quantify and compare the kinematics of movement during early learning of full-body sensorimotor orienting.

Virtual Reality for Anxiety Disorders

Directory of Open Access Journals (Sweden)

Elif Uzumcu

2018-03-01

Full Text Available Virtual reality is a relatively new exposure tool that uses three-dimensional computer-graphics-based technologies which allow the individual to feel as if they are physically inside the virtual environment by misleading their senses. As virtual reality studies have become popular in the field of clinical psychology in recent years, it has been observed that virtual-reality-based therapies have a wide range of application areas, especially on anxiety disorders. Studies indicate that virtual reality can be more realistic than mental imagery and can create a stronger feeling of ԰resenceԻ that it is a safer starting point compared to in vivo exposure; and that it can be applied in a more practical and controlled manner. The aim of this review is to investigate exposure studies based on virtual reality in anxiety disorders (specific phobias, panic disorder and agoraphobias, generalized anxiety disorder, social phobia, posttraumatic stress disorder and obsessive compulsive disorder.

The ethnography of virtual reality

Directory of Open Access Journals (Sweden)

Gavrilović Ljiljana 1

2004-01-01

Full Text Available This paper discusses possible application of ethnographic research in the realm of virtual reality, especially in the relationship between cultures in virtual communities. This represents an entirely new area of ethnographic research and therefore many adjustments in the research design are needed for example, a development of a specific method of data gathering and tools for their verification. A virtual, cyber space is a version of social space more or less synchronous with it, but without the, "real", that is, physical presence of the people who create it. This virtual reality, defined and bounded by virtual space, is in fact real - and though we are not able to observe real, physical parameters of its existence, we can perceive its consequences. In sum, an innovative ethnographic research method is fully applicable for exploring the realm of virtual reality; in order to do so we need to expand, in addition to the new research design and methods, the field of science itself.

Virtual reality technology and applications

CERN Document Server

Mihelj, Matjaž; Beguš, Samo

2014-01-01

As virtual reality expands from the imaginary worlds of science fiction and pervades every corner of everyday life, it is becoming increasingly important for students and professionals alike to understand the diverse aspects of this technology. This book aims to provide a comprehensive guide to the theoretical and practical elements of virtual reality, from the mathematical and technological foundations of virtual worlds to the human factors and the applications that enrich our lives: in the fields of medicine, entertainment, education and others. After providing a brief introduction to the topic, the book describes the kinematic and dynamic mathematical models of virtual worlds. It explores the many ways a computer can track and interpret human movement, then progresses through the modalities that make up a virtual world: visual, acoustic and haptic. It explores the interaction between the actual and virtual environments, as well as design principles of the latter. The book closes with an examination of diff...

Surgery applications of virtual reality

Science.gov (United States)

Rosen, Joseph

1994-01-01

Virtual reality is a computer-generated technology which allows information to be displayed in a simulated, bus lifelike, environment. In this simulated 'world', users can move and interact as if they were actually a part of that world. This new technology will be useful in many different fields, including the field of surgery. Virtual reality systems can be used to teach surgical anatomy, diagnose surgical problems, plan operations, simulate and perform surgical procedures (telesurgery), and predict the outcomes of surgery. The authors of this paper describe the basic components of a virtual reality surgical system. These components include: the virtual world, the virtual tools, the anatomical model, the software platform, the host computer, the interface, and the head-coupled display. In the chapter they also review the progress towards using virtual reality for surgical training, planning, telesurgery, and predicting outcomes. Finally, the authors present a training system being developed for the practice of new procedures in abdominal surgery.

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.

Virtual Tower

International Nuclear Information System (INIS)

Wayne, R.A.

1997-01-01

The primary responsibility of an intrusion detection system (IDS) operator is to monitor the system, assess alarms, and summon and coordinate the response team when a threat is acknowledged. The tools currently provided to the operator are somewhat limited: monitors must be switched, keystrokes must be entered to call up intrusion sensor data, and communication with the response force must be maintained. The Virtual tower is an operator interface assembled from low-cost commercial-off-the-shelf hardware and software; it enables large amounts of data to be displayed in a virtual manner that provides instant recognition for the operator and increases assessment accuracy in alarm annunciator and control systems. This is accomplished by correlating and fusing the data into a 360-degree visual representation that employs color, auxiliary attributes, video, and directional audio to prompt the operator. The Virtual Tower would be a valuable low-cost enhancement to existing systems

Development of a Virtual Museum Including a 4d Presentation of Building History in Virtual Reality

Science.gov (United States)

Kersten, T. P.; Tschirschwitz, F.; Deggim, S.

2017-02-01

In the last two decades the definition of the term "virtual museum" changed due to rapid technological developments. Using today's available 3D technologies a virtual museum is no longer just a presentation of collections on the Internet or a virtual tour of an exhibition using panoramic photography. On one hand, a virtual museum should enhance a museum visitor's experience by providing access to additional materials for review and knowledge deepening either before or after the real visit. On the other hand, a virtual museum should also be used as teaching material in the context of museum education. The laboratory for Photogrammetry & Laser Scanning of the HafenCity University Hamburg has developed a virtual museum (VM) of the museum "Alt-Segeberger Bürgerhaus", a historic town house. The VM offers two options for visitors wishing to explore the museum without travelling to the city of Bad Segeberg, Schleswig-Holstein, Germany. Option a, an interactive computer-based, tour for visitors to explore the exhibition and to collect information of interest or option b, to immerse into virtual reality in 3D with the HTC Vive Virtual Reality System.

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....

Saving Money and Time with Virtual Server

CERN Document Server

Sanders, Chris

2006-01-01

Microsoft Virtual Server 2005 consistently proves to be worth its weight in gold, with new implementations thought up every day. With this product now a free download from Microsoft, scores of new users are able to experience what the power of virtualization can do for their networks. This guide is aimed at network administrators who are interested in ways that Virtual Server 2005 can be implemented in their organizations in order to save money and increase network productivity. It contains information on setting up a virtual network, virtual consolidation, virtual security, virtual honeypo

Management and Engineering of Virtual Enterprises

DEFF Research Database (Denmark)

Tølle, Martin

) Component layer: consists of reusable components and modules. - Each layer builds on the previous one, i.e. the VE concept is captured in VERA, and the VERA can be used to structure each of the VERAM components. * C) A methodology for virtual enterprise named VEM (Virtual Enterprise Methodology) - One...... to the set up of virtual enterprises. Types of work preparation include definitions (e.g. shared terminology), ICT support (e.g. infrastructure and applications), procedures (e.g. how to set up virtual enterprises, partner selection), reference models (e.g. contract models and product structure) and the like....... * B) A framework and a reference architecture for virtual enterprises named VERAM (Virtual Enterprise Reference Architecture and Methodology) and VERA (Virtual Enterprise Reference Architecture) respectively. - VERAM is a framework that structures the body of knowledge related to preparation, set up...

Virtual Reality in the Classroom.

Science.gov (United States)

Pantelidis, Veronica S.

1993-01-01

Considers the concept of virtual reality; reviews its history; describes general uses of virtual reality, including entertainment, medicine, and design applications; discusses classroom uses of virtual reality, including a software program called Virtus WalkThrough for use with a computer monitor; and suggests future possibilities. (34 references)…

Interacting with a Virtual Conductor

NARCIS (Netherlands)

Bos, Pieter; Reidsma, Dennis; Ruttkay, Zsófia; Nijholt, Anton; Harper, Richard; Rauterberg, Matthias; Combetto, Marco

This paper presents a virtual embodied agent that can conduct musicians in a live performance. The virtual conductor conducts music specified by a MIDI file and uses input from a microphone to react to the tempo of the musicians. The current implementation of the virtual conductor can interact with

Virtual reality in surgical training.

Science.gov (United States)

Lange, T; Indelicato, D J; Rosen, J M

2000-01-01

Virtual reality in surgery and, more specifically, in surgical training, faces a number of challenges in the future. These challenges are building realistic models of the human body, creating interface tools to view, hear, touch, feel, and manipulate these human body models, and integrating virtual reality systems into medical education and treatment. A final system would encompass simulators specifically for surgery, performance machines, telemedicine, and telesurgery. Each of these areas will need significant improvement for virtual reality to impact medicine successfully in the next century. This article gives an overview of, and the challenges faced by, current systems in the fast-changing field of virtual reality technology, and provides a set of specific milestones for a truly realistic virtual human body.

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…

Analisis Gameplay Game Genre Virtual Pet

Directory of Open Access Journals (Sweden)

Abi Senoprabowo

2015-02-01

Full Text Available Game adalah struktur interaktif yang membuat pemain berjuang menuju sebuah tujuan. Game dapat memberikan emosi dan mood, menghubungkan dengan orang latihan, sarana latihan, serta dapat memberikan edukasi. Salah satu game yang berkembang saat ini adalah game bergenre Virtual pet. Game virtual pet merupakan game simulasi memelihara sesuatu. Virtual pet memiliki gameplay yang menarik dan menyenangkan yang membuat pemain seolah-olah benar-benar memiliki binatang peliharaan mereka sendiri. Virtual pet dianggap oleh sebagian besar penggunanya dapat memberikan kegembiraan serta rasa kasih sayang karena tingkat interaksinya yang baik. Banyak pengembang game pemula yang mengembangkan genre ini sebagai game yang mereka buat karena kemudahaan dan tingkat penggunanya yang banyak. Akan tetapi banyak dari pengembang game pemula tidak memperhatikan tingkat keberlanjutan game virtual pet yang mereka buat sehingga membuat pemain cepat bosan. Pada penelitian ini, analisis game bergenre virtual pet yang sudah sukses dibuat seperti Zombigotchi, Tamagotchi Unicorn, dan Bird Land, diharapkan dapat membantu para pengembang game pemula agar mengetahui cara merancang dan mengembangkan game virtual pet dengan baik. Kata Kunci: game, gameplay, virtual pet

Predicting the effectiveness of virtual reality relaxation on pain and anxiety when added to PCA morphine in patients having burns dressings changes.

Science.gov (United States)

Konstantatos, A H; Angliss, M; Costello, V; Cleland, H; Stafrace, S

2009-06-01

Pain arising in burns sufferers is often severe and protracted. The prospect of a dressing change can heighten existing pain by impacting both physically and psychologically. In this trial we examined whether pre-procedural virtual reality guided relaxation added to patient controlled analgesia with morphine reduced pain severity during awake dressings changes in burns patients. We conducted a prospective randomized clinical trial in all patients with burns necessitating admission to a tertiary burns referral centre. Eligible patients requiring awake dressings changes were randomly allocated to single use virtual reality relaxation plus intravenous morphine patient controlled analgesia (PCA) infusion or to intravenous morphine patient controlled analgesia infusion alone. Patients rated their worst pain intensity during the dressing change using a visual analogue scale. The primary outcome measure was presence of 30% or greater difference in pain intensity ratings between the groups in estimation of worst pain during the dressing change. Of 88 eligible and consenting patients having awake dressings changes, 43 were assigned to virtual reality relaxation plus intravenous morphine PCA infusion and 43 to morphine PCA infusion alone. The group receiving virtual reality relaxation plus morphine PCA infusion reported significantly higher pain intensities during the dressing change (mean=7.3) compared with patients receiving morphine PCA alone (mean=5.3) (p=0.003) (95% CI 0.6-2.8). The addition of virtual reality guided relaxation to morphine PCA infusion in burns patients resulted in a significant increase in pain experienced during awake dressings changes. In the absence of a validated predictor for responsiveness to virtual reality relaxation such a therapy cannot be recommended for general use in burns patients having awake dressings changes.

Ethnography in a Virtual World

Science.gov (United States)

Shumar, Wesley; Madison, Nora

2013-01-01

This article situates the discussion of virtual ethnography within the larger political/economic changes of twenty-first century consumer capitalism and suggests that increasingly our entire social world is a virtual world and that there were very particular utopian and dystopian framings of virtual community growing out of that history. The…

Virtual learning environment for managing costs of dressings for pressure ulcers

Directory of Open Access Journals (Sweden)

Marta Cristiane Alves Pereira

2014-06-01

Full Text Available A descriptive and applied study aimed at describing the construction and assessment of a virtual learning environment on the topic of cost management of pressure ulcer dressings, using WebQuest methodology. For the planning and development phases, we used simple and accessible technological resources, focused on educational aspects. During the assessment phase, four computer science specialists, four nursing professors and four nursing professionals who worked with cost management evaluated technical aspects (Response Time and Interface Quality as well as educational ones (Content, Activity, Interaction. These aspects received positive evaluations (over 86% of criteria were fulfilled, except for Response Time (62% were totally fulfilled and 30% partially fulfilled. The results demonstrated that it is possible to make use of virtual learning environments with undergraduate nursing students in order to impact education regarding material cost management in nursing. doi: 10.5216/ree.v16i2.22161.

Virtual superheroes: using superpowers in virtual reality to encourage prosocial behavior.

Directory of Open Access Journals (Sweden)

Robin S Rosenberg

Full Text Available BACKGROUND: Recent studies have shown that playing prosocial video games leads to greater subsequent prosocial behavior in the real world. However, immersive virtual reality allows people to occupy avatars that are different from them in a perceptually realistic manner. We examine how occupying an avatar with the superhero ability to fly increases helping behavior. PRINCIPAL FINDINGS: Using a two-by-two design, participants were either given the power of flight (their arm movements were tracked to control their flight akin to Superman's flying ability or rode as a passenger in a helicopter, and were assigned one of two tasks, either to help find a missing diabetic child in need of insulin or to tour a virtual city. Participants in the "super-flight" conditions helped the experimenter pick up spilled pens after their virtual experience significantly more than those who were virtual passengers in a helicopter. CONCLUSION: The results indicate that having the "superpower" of flight leads to greater helping behavior in the real world, regardless of how participants used that power. A possible mechanism for this result is that having the power of flight primed concepts and prototypes associated with superheroes (e.g., Superman. This research illustrates the potential of using experiences in virtual reality technology to increase prosocial behavior in the physical world.

Virtual Peace Education

Science.gov (United States)

Firer, Ruth

2008-01-01

This article is based on the convictions that peace education is the basis for any sustainable non-violent relations between parties in a conflict, and that virtual peace education is almost the only feasible way to practise peace education in an open violent conflict as is the current Israeli/Palestinians one. Moreover, virtual peace education…

Developing a Virtual Book - Material for Virtual Learning Environments

Directory of Open Access Journals (Sweden)

Anne Karin Larsen

2007-12-01

Full Text Available This article describes the process of, and considerations taken when Virtual Learning Materials were developed for an international study in Comparative Social Work arranged by the VIRCLASS project. The steps taken and the elements included in the Virtual Book – A Guide to Social Work in Europe are presented in details to inform others who are planning to make virtual learning materials. Students from 11 countries in Europe participated, and their reception of this material and learning outcomes from using it are analysed and presented. Furthermore; the article discuss how the learning material contributes to students’ learning, how a common understanding of practice enhances knowledge-building and in what way audio-visual learning material can contribute to good learning in e-learning courses. The results are discussed in relation to theories about composite texts and community of inquiry, and outlines some challenges for e-teachers’ competences.

Virtual reality training improves turning capacity and functional reach in stroke patients

International Nuclear Information System (INIS)

Malik, A.N.; Masood, T.

2017-01-01

Objective: To determine the added effects of virtual reality training on turning capacity, gait parameters and functional reach capacity of stroke patients compared to task oriented training alone. Methodology: A randomized control trial was conducted from February 2016 to July 2106 at Physical Rehabilitation Department Pakistan Railway Hospital, Rawalpindi, Pakistan. Twenty stroke patients were selected through purposive sampling. The patients were randomly assigned through sealed envelope method into two groups; Task Oriented Training (TOT) and Virtual Reality Training (VRT) Group. The standardized tools were used for assessment. The TOT was provided for 4 days per week for 6 weeks while VRT group received additional exer-gaming training during sessions. Results: Significant improvement was observed in both groups regarding reaching forward, turning 360, gait pivot turn (p a 0.01) and FRT (p a 0.001). The two groups were statistically different from each other in terms of turning capacity, reaching forward, gait pivot turn and functional reach after 6 weeks of intervention (p a 0.05) Conclusion: Addition of virtual reality training further improves the significant improvement caused by task oriented training on turning capacity, reaching forward, gait pivot turn and functional reach in stroke patients. (author)

A virtual tour of virtual reality

Science.gov (United States)

Harris, Margaret

2018-03-01

Virtual-reality glasses might still be on the starting blocks, but plenty of companies are working on the technology. Margaret Harris tries on some examples at the Photonics West show in San Francisco

Representation of Patients' Hand Modulates Fear Reactions of Patients with Spider Phobia in Virtual Reality.

Science.gov (United States)

Peperkorn, Henrik M; Diemer, Julia E; Alpers, Georg W; Mühlberger, Andreas

2016-01-01

Embodiment (i.e., the involvement of a bodily representation) is thought to be relevant in emotional experiences. Virtual reality (VR) is a capable means of activating phobic fear in patients. The representation of the patient's body (e.g., the right hand) in VR enhances immersion and increases presence, but its effect on phobic fear is still unknown. We analyzed the influence of the presentation of the participant's hand in VR on presence and fear responses in 32 women with spider phobia and 32 matched controls. Participants sat in front of a table with an acrylic glass container within reaching distance. During the experiment this setup was concealed by a head-mounted display (HMD). The VR scenario presented via HMD showed the same setup, i.e., a table with an acrylic glass container. Participants were randomly assigned to one of two experimental groups. In one group, fear responses were triggered by fear-relevant visual input in VR (virtual spider in the virtual acrylic glass container), while information about a real but unseen neutral control animal (living snake in the acrylic glass container) was given. The second group received fear-relevant information of the real but unseen situation (living spider in the acrylic glass container), but visual input was kept neutral VR (virtual snake in the virtual acrylic glass container). Participants were instructed to touch the acrylic glass container with their right hand in 20 consecutive trials. Visibility of the hand was varied randomly in a within-subjects design. We found for all participants that visibility of the participant's hand increased presence independently of the fear trigger. However, in patients, the influence of the virtual hand on fear depended on the fear trigger. When fear was triggered perceptually, i.e., by a virtual spider, the virtual hand increased fear. When fear was triggered by information about a real spider, the virtual hand had no effect on fear. Our results shed light on the

Learning Ethics through Virtual Fieldtrips: Teaching Ethical Theories through Virtual Experiences

Science.gov (United States)

Houser, Rick; Thoma, Steve; Coppock, Amanda; Mazer, Matthew; Midkiff, Lewis; Younanian, Marisa; Young, Sarah

2011-01-01

Teaching ethical reasoning is considered an important component of the undergraduate learning experience. A recent approach to teaching using experiential learning is through virtual worlds such as Second Life. We discuss how ethics may be taught using experiential learning in the virtual world of Second Life. Participants in the class in this…

Leveraging KVM Events to Detect Cache-Based Side Channel Attacks in a Virtualization Environment

Directory of Open Access Journals (Sweden)

Ady Wahyudi Paundu

2018-01-01

Full Text Available Cache-based side channel attack (CSCa techniques in virtualization systems are becoming more advanced, while defense methods against them are still perceived as nonpractical. The most recent CSCa variant called Flush + Flush has showed that the current detection methods can be easily bypassed. Within this work, we introduce a novel monitoring approach to detect CSCa operations inside a virtualization environment. We utilize the Kernel Virtual Machine (KVM event data in the kernel and process this data using a machine learning technique to identify any CSCa operation in the guest Virtual Machine (VM. We evaluate our approach using Receiver Operating Characteristic (ROC diagram of multiple attack and benign operation scenarios. Our method successfully separate the CSCa datasets from the non-CSCa datasets, on both trained and nontrained data scenarios. The successful classification also include the Flush + Flush attack scenario. We are also able to explain the classification results by extracting the set of most important features that separate both classes using their Fisher scores and show that our monitoring approach can work to detect CSCa in general. Finally, we evaluate the overhead impact of our CSCa monitoring method and show that it has a negligible computation overhead on the host and the guest VM.

Virtual reality applications to the training

International Nuclear Information System (INIS)

Gomez-Arguello, B.; Gonzalez, F.; Salve, R.

2003-01-01

The application of Virtual Reality for training in radiological environments allows the planning analysis and training in tasks which will be performed later in a real environment, saving doses to the real workers. There are many advantages of using VR in the training field comparing with a traditional training based on entries to the radiological areas and 2D studies: The application of the VR to the nuclear industry will provide in a middle period a more efficient training in radiological environments, giving more fidelity to the real world, enforcing the spatial skills and the active learning and allowing the visualization of the radiation field and the more suitable routes. TECNATOM has been working in VR field through several to test the adequacy of this methodology. Specifically, the SIMU2 project has been developed. This is a Virtual Reality highly flexible based software tool which allows for the simulation of human tasks in radiological environments, providing dosimetric information in all the points of the environment as well as the doses received by the workers during the simulated tasks performance. This application can be used as a support tool in training courses, to train the operators who will perform the real operation. Besides, the system allows the trainer to enter comments and explanations for each selected action or for the complete task. (Author) 8 refs

Virtual Patients in a Behavioral Medicine Massive Open Online Course (MOOC): A Qualitative and Quantitative Analysis of Participants' Perceptions.

Science.gov (United States)

Berman, Anne H; Biguet, Gabriele; Stathakarou, Natalia; Westin-Hägglöf, Beata; Jeding, Kerstin; McGrath, Cormac; Zary, Nabil; Kononowicz, Andrzej A

2017-10-01

The purpose of this article is to explore learners' perceptions of using virtual patients in a behavioral medicine Massive Open Online Course (MOOCs) and thereby describe innovative ways of disseminating knowledge in health-related areas. A 5-week MOOC on behavioral medicine was hosted on the edX platform. The authors developed two branched virtual patients consisting of video recordings of a live standardized patient, with multiple clinical decision points and narration unfolding depending on learners' choices. Students interacted with the virtual patients to treat stress and sleep problems. Answers to the exit survey and participant comments from the discussion forum were analyzed qualitatively and quantitatively. In total, 19,236 participants enrolled in the MOOC, out of which 740 received the final certificate. The virtual patients were completed by 2317 and 1640 participants respectively. Among survey respondents (n = 442), 83.1% agreed that the virtual patient exercise was helpful. The qualitative analysis resulted in themes covering what it was like to work with the virtual patient, with subthemes on learner-centered education, emotions/eustress, game comparisons, what the participants learned, what surprised them, how confident participants felt about applying interventions in practice, suggestions for improvement, and previous experiences of virtual patients. Students were enthusiastic about interacting with the virtual patients as a means to apply new knowledge about behavioral medicine interventions. The most common suggestion was to incorporate more interactive cases with various levels of complexity. Further research should include patient outcomes and focus on interprofessional aspects of learning with virtual patients in a MOOC.

Development of a virtual reality training curriculum for phacoemulsification surgery.

Science.gov (United States)

Spiteri, A V; Aggarwal, R; Kersey, T L; Sira, M; Benjamin, L; Darzi, A W; Bloom, P A

2014-01-01

Training within a proficiency-based virtual reality (VR) curriculum may reduce errors during real surgical procedures. This study used a scientific methodology to develop a VR training curriculum for phacoemulsification surgery (PS). Ten novice-(n) (performed 500) surgeons were recruited. Construct validity was defined as the ability to differentiate between the three levels of experience, based on the simulator-derived metrics for two abstract modules (four tasks) and three procedural modules (five tasks) on a high-fidelity VR simulator. Proficiency measures were based on the performance of experienced surgeons. Abstract modules demonstrated a 'ceiling effect' with construct validity established between groups (n) and (i) but not between groups (i) and (e)-Forceps 1 (46, 87, and 95; P<0.001). Increasing difficulty of task showed significantly reduced performance in (n) but minimal difference for (i) and (e)-Anti-tremor 4 (0, 51, and 59; P<0.001), Forceps 4 (11, 73, and 94; P<0.001). Procedural modules were found to be construct valid between groups (n) and (i) and between groups (i) and (e)-Lens-cracking (0, 22, and 51; P<0.05) and Phaco-quadrants (16, 53, and 87; P<0.05). This was also the case with Capsulorhexis (0, 19, and 63; P<0.05) with the performance decreasing in the (n) and (i) group but improving in the (e) group (0, 55, and 73; P<0.05) and (0, 48, and 76; P<0.05) as task difficulty increased. Experienced/intermediate benchmark skill levels are defined allowing the development of a proficiency-based VR training curriculum for PS for novices using a structured scientific methodology.

Virtual Stationary Automata for Mobile Networks

National Research Council Canada - National Science Library

Dolev, Shlomi; Gilbert, Seth; Lahiani, Limor; Lynch, Nancy; Nolte, Tina

2005-01-01

We define a programming abstraction for mobile networks called the Virtual Stationary Automata programming layer, consisting of real mobile clients, virtual timed I/O automata called virtual stationary automata (VSAs...

Development of children male virtual simulator of 15 years old using anatomic parameters of ICRP number 89; Desenvolvimento de um simulador pediatrico virtual masculino de 15 anos com base nos parametros anatomicos da ICRP de numero 89

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Erick da S.; Junior, Alberico B. de C.; Tavares, Paulo V. dos S. [Universidade Federal de Sergipe (UFSE), Sao Cristovao, SE (Brazil)

2016-07-01

Computational dosimetry is engaged in radiation dose estimate received by an individual exposed to a radiation field and evaluates the cancer risk associated with this type of exposure. To perform such an assessment is used virtual simulators representing humans. Currently, with the development of graphic animation software, the development of these simulators was facilitated using only knowledge of human anatomy to prepare various types of simulators (man, woman, child and baby) in various positions (sitting, standing, running) or part thereof (head, trunk and limbs). In this project, we built a virtual boy 15 years in mesh and voxels to dare in computational dosimetry. (author)

Leap Motion-based virtual reality training for improving motor functional recovery of upper limbs and neural reorganization in subacute stroke patients

Science.gov (United States)

Wang, Zun-rong; Wang, Ping; Xing, Liang; Mei, Li-ping; Zhao, Jun; Zhang, Tong

2017-01-01

Virtual reality is nowadays used to facilitate motor recovery in stroke patients. Most virtual reality studies have involved chronic stroke patients; however, brain plasticity remains good in acute and subacute patients. Most virtual reality systems are only applicable to the proximal upper limbs (arms) because of the limitations of their capture systems. Nevertheless, the functional recovery of an affected hand is most difficult in the case of hemiparesis rehabilitation after a stroke. The recently developed Leap Motion controller can track the fine movements of both hands and fingers. Therefore, the present study explored the effects of a Leap Motion-based virtual reality system on subacute stroke. Twenty-six subacute stroke patients were assigned to an experimental group that received virtual reality training along with conventional occupational rehabilitation, and a control group that only received conventional rehabilitation. The Wolf motor function test (WMFT) was used to assess the motor function of the affected upper limb; functional magnetic resonance imaging was used to measure the cortical activation. After four weeks of treatment, the motor functions of the affected upper limbs were significantly improved in all the patients, with the improvement in the experimental group being significantly better than in the control group. The action performance time in the WMFT significantly decreased in the experimental group. Furthermore, the activation intensity and the laterality index of the contralateral primary sensorimotor cortex increased in both the experimental and control groups. These results confirmed that Leap Motion-based virtual reality training was a promising and feasible supplementary rehabilitation intervention, could facilitate the recovery of motor functions in subacute stroke patients. The study has been registered in the Chinese Clinical Trial Registry (registration number: ChiCTR-OCH-12002238). PMID:29239328

Leap Motion-based virtual reality training for improving motor functional recovery of upper limbs and neural reorganization in subacute stroke patients.

Science.gov (United States)

Wang, Zun-Rong; Wang, Ping; Xing, Liang; Mei, Li-Ping; Zhao, Jun; Zhang, Tong

2017-11-01

Virtual reality is nowadays used to facilitate motor recovery in stroke patients. Most virtual reality studies have involved chronic stroke patients; however, brain plasticity remains good in acute and subacute patients. Most virtual reality systems are only applicable to the proximal upper limbs (arms) because of the limitations of their capture systems. Nevertheless, the functional recovery of an affected hand is most difficult in the case of hemiparesis rehabilitation after a stroke. The recently developed Leap Motion controller can track the fine movements of both hands and fingers. Therefore, the present study explored the effects of a Leap Motion-based virtual reality system on subacute stroke. Twenty-six subacute stroke patients were assigned to an experimental group that received virtual reality training along with conventional occupational rehabilitation, and a control group that only received conventional rehabilitation. The Wolf motor function test (WMFT) was used to assess the motor function of the affected upper limb; functional magnetic resonance imaging was used to measure the cortical activation. After four weeks of treatment, the motor functions of the affected upper limbs were significantly improved in all the patients, with the improvement in the experimental group being significantly better than in the control group. The action performance time in the WMFT significantly decreased in the experimental group. Furthermore, the activation intensity and the laterality index of the contralateral primary sensorimotor cortex increased in both the experimental and control groups. These results confirmed that Leap Motion-based virtual reality training was a promising and feasible supplementary rehabilitation intervention, could facilitate the recovery of motor functions in subacute stroke patients. The study has been registered in the Chinese Clinical Trial Registry (registration number: ChiCTR-OCH-12002238).

Leap Motion-based virtual reality training for improving motor functional recovery of upper limbs and neural reorganization in subacute stroke patients

Directory of Open Access Journals (Sweden)

Zun-rong Wang

2017-01-01

Full Text Available Virtual reality is nowadays used to facilitate motor recovery in stroke patients. Most virtual reality studies have involved chronic stroke patients; however, brain plasticity remains good in acute and subacute patients. Most virtual reality systems are only applicable to the proximal upper limbs (arms because of the limitations of their capture systems. Nevertheless, the functional recovery of an affected hand is most difficult in the case of hemiparesis rehabilitation after a stroke. The recently developed Leap Motion controller can track the fine movements of both hands and fingers. Therefore, the present study explored the effects of a Leap Motion-based virtual reality system on subacute stroke. Twenty-six subacute stroke patients were assigned to an experimental group that received virtual reality training along with conventional occupational rehabilitation, and a control group that only received conventional rehabilitation. The Wolf motor function test (WMFT was used to assess the motor function of the affected upper limb; functional magnetic resonance imaging was used to measure the cortical activation. After four weeks of treatment, the motor functions of the affected upper limbs were significantly improved in all the patients, with the improvement in the experimental group being significantly better than in the control group. The action performance time in the WMFT significantly decreased in the experimental group. Furthermore, the activation intensity and the laterality index of the contralateral primary sensorimotor cortex increased in both the experimental and control groups. These results confirmed that Leap Motion-based virtual reality training was a promising and feasible supplementary rehabilitation intervention, could facilitate the recovery of motor functions in subacute stroke patients. The study has been registered in the Chinese Clinical Trial Registry (registration number: ChiCTR-OCH-12002238.

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.

A Virtual Tomb for Kelvingrove: Virtual Reality, Archaeology and Education

Directory of Open Access Journals (Sweden)

Melissa M. Terras

1999-11-01

Full Text Available The use of computers as an educational resource in museums is becoming increasingly popular as more and more institutions realise that multimedia displays are very successful in imparting a broad variety of information. Although three-dimensional reconstructions of sites and structures have been used in archaeology for many years, the majority of museum computer installations have dealt with two-dimensional media because of the costs, equipment and labour involved in producing interactive 3D scenes. The birth of VRML (Virtual Reality Modeling Language has changed the way virtual reality is implemented and viewed. As an internet protocol, VRML can be used on most major platforms and implemented by anyone with a word-processing package, an internet browser, and the relevant plug-in. There is no reason why this new technology cannot be adopted by archaeologists and museums to produce virtual reality models of structures, sites and objects to aid the research of specialists and the education of the public. This project (undertaken at the Humanities Advanced Technology and Information Institute, University of Glasgow, Scotland, between May and October 1998 investigated the practicalities involved in using VRML to create a virtual reality model for use in a public space. A model of the Egyptian tomb of Sen-nedjem was developed for installation in the Egyptian Gallery of the Kelvingrove Museum and Art Gallery, Glasgow, in the hope that the introduction of this computer display would encourage the museum visitor's interest in the gallery's existing artefacts. Creation of the model would also investigate the possibility of using VRML to build accurate archaeological reconstructions cheaply and efficiently using publicly available software and existing archaeological resources. A fully functioning virtual reality model of the tomb of Sen-nedjem has been created, incorporating interactive elements, photorealistic representation, and animation, and this

A conceptualisation of the relationship between virtual experience and cybernauts' satisfaction with virtual communities

OpenAIRE

Bouattour , Dorra; Debos , Franck; Abdellatif , Tarek

2015-01-01

International audience; In this research, we developed and tested an integrated model relating individuals' satisfaction with their experiential values in virtual communities. Using a realised factorial analysis and regression, we identified the factors that influence member satisfaction in virtual communities. Adopting Mathwick et al.'s (2001) concept of experiential value, we proposed a conceptualisation of a virtual experience that fits closely with the original nomological framework advoc...

Facilitating learning through an international virtual collaborative practice: A case study.

Science.gov (United States)

Wihlborg, Monne; Friberg, Elizabeth E; Rose, Karen M; Eastham, Linda

2018-02-01

Internationalisation of higher education involving information and communication technology such as e-learning opens opportunities for innovative learning approaches across nations and cultures. Describe a case in practice of collaborative and transformative learning in relation to 'internationalisation on home grounds' with the broader learning objective of 'becoming aware and knowledgeable'. A mutually developed project established a virtual international collaborative exchange for faculty and students using a course management software (MOODLE) and open access technology (Adobe CONNECT). Two research universities in Sweden and the United States. Approximately 90 nursing students from each university per semester over several semesters. A collaborative process to develop a joint learning community to construct a virtual module and learning activity involving academics and nursing students in two countries using principles of meaning construction and negotiated learning. Developed possibilities for dealing with the challenges and finding strategies for a future higher education system that opens dialogues worldwide. Virtual international exchanges open innovative communication and learning contexts across nations and cultures. Internationalisation is so much more than students and teachers' mobility. 'Internationalisation on home grounds' (internationalisation for all) should receive more attention to support faculty and student collaboration, learning, and professional development. Copyright © 2017 Elsevier Ltd. All rights reserved.

Virtual environments simulation in research reactor

Science.gov (United States)

Muhamad, Shalina Bt. Sheik; Bahrin, Muhammad Hannan Bin

2017-01-01

Virtual reality based simulations are interactive and engaging. It has the useful potential in improving safety training. Virtual reality technology can be used to train workers who are unfamiliar with the physical layout of an area. In this study, a simulation program based on the virtual environment at research reactor was developed. The platform used for virtual simulation is 3DVia software for which it's rendering capabilities, physics for movement and collision and interactive navigation features have been taken advantage of. A real research reactor was virtually modelled and simulated with the model of avatars adopted to simulate walking. Collision detection algorithms were developed for various parts of the 3D building and avatars to restrain the avatars to certain regions of the virtual environment. A user can control the avatar to move around inside the virtual environment. Thus, this work can assist in the training of personnel, as in evaluating the radiological safety of the research reactor facility.

Virtually naked: virtual environment reveals sex-dependent nature of skin disclosure.

Directory of Open Access Journals (Sweden)

Anna M Lomanowska

Full Text Available The human tendency to reveal or cover naked skin reflects a competition between the individual propensity for social interactions related to sexual appeal and interpersonal touch versus climatic, environmental, physical, and cultural constraints. However, due to the ubiquitous nature of these constraints, isolating on a large scale the spontaneous human tendency to reveal naked skin has remained impossible. Using the online 3-dimensional virtual world of Second Life, we examined spontaneous human skin-covering behavior unhindered by real-world climatic, environmental, and physical variables. Analysis of hundreds of avatars revealed that virtual females disclose substantially more naked skin than virtual males. This phenomenon was not related to avatar hypersexualization as evaluated by measurement of sexually dimorphic body proportions. Furthermore, analysis of skin-covering behavior of a population of culturally homogeneous avatars indicated that the propensity of female avatars to reveal naked skin persisted despite explicit cultural norms promoting less revealing attire. These findings have implications for further understanding how sex-specific aspects of skin disclosure influence human social interactions in both virtual and real settings.

Early Science Learning with a Virtual Tutor through Multimedia Explanations and Feedback on Spoken Questions

Science.gov (United States)

Hautala, Jarkko; Baker, Doris Luft; Keurulainen, Aleksi; Ronimus, Miia; Richardson, Ulla; Cole, Ronald

2018-01-01

The purpose of this pilot study with a within-subject design was to gain a deeper understanding about the promise and restrictions of a virtual tutoring system designed to teach science to first grade students in Finland. Participants were 61 students who received six tutoring science sessions of approximately 20 min each. Sessions consisted of a…

Virtual polytopes

International Nuclear Information System (INIS)

Panina, G Yu; Streinu, I

2015-01-01

Originating in diverse branches of mathematics, from polytope algebra and toric varieties to the theory of stressed graphs, virtual polytopes represent a natural algebraic generalization of convex polytopes. Introduced as elements of the Grothendieck group associated to the semigroup of convex polytopes, they admit a variety of geometrizations. The present survey connects the theory of virtual polytopes with other geometrical subjects, describes a series of geometrizations together with relations between them, and gives a selection of applications. Bibliography: 50 titles

Thoracoscopic surgery for pulmonary metastases after chemotherapy using a tailor-made virtual lung

International Nuclear Information System (INIS)

Akiba, Tadashi; Marushima, Hideki; Kinoshita, Satoki; Kamiya, Noriteru; Odaka, Makoto; Takeyama, Hiroshi; Morikawa, Toshiaki

2011-01-01

Details with regard to the standard criteria for a therapeutic metastasectomy and the use of video-assisted thoracic surgery (VATS) remain elusive. To evaluate the feasibility of VATS using a tailor-made virtual lung for patients with pulmonary metastases after chemotherapy, we reviewed the following cases. Clinical data from October 2006 to April 2010 were obtained from patients who received chemotherapy before a pulmonary metastasectomy (lobectomy or segmentectomy). VATS was the primarily selected surgical approach except for treating hilar lesions. A lobectomy was performed when the metastasis was greater than 3.0 cm in diameter or located deeply in the lobe. Tailor-made virtual lungs were created using three-dimensional multidetector computed tomography before lobectomy on a routine basis. The virtual lung consisted of three-dimensional pulmonary vessels, a tracheobronchial tree, pulmonary parenchyma, and tumors. Twelve operations, consisting of 1 segmentectomy, 10 lobectomies, and 1 wedge bronchoplasty upper lobectomy, were performed on 11 patients during the study period. VATS was completed in 10 of these 12 operations. The mean operative time for the lobectomies was 257 min, and the mean operative bleeding volume was 215 ml. Two cases experienced postoperative transient atrial fibrillation, and no mortalities associated with these operations were reported. VATS was performed safely in instances of metastasectomy after chemotherapy, and the tailor-made virtual lung assisted in lung orientation during the operation. (author)

Virtualization and cloud computing in dentistry.

Science.gov (United States)

Chow, Frank; Muftu, Ali; Shorter, Richard

2014-01-01

The use of virtualization and cloud computing has changed the way we use computers. Virtualization is a method of placing software called a hypervisor on the hardware of a computer or a host operating system. It allows a guest operating system to run on top of the physical computer with a virtual machine (i.e., virtual computer). Virtualization allows multiple virtual computers to run on top of one physical computer and to share its hardware resources, such as printers, scanners, and modems. This increases the efficient use of the computer by decreasing costs (e.g., hardware, electricity administration, and management) since only one physical computer is needed and running. This virtualization platform is the basis for cloud computing. It has expanded into areas of server and storage virtualization. One of the commonly used dental storage systems is cloud storage. Patient information is encrypted as required by the Health Insurance Portability and Accountability Act (HIPAA) and stored on off-site private cloud services for a monthly service fee. As computer costs continue to increase, so too will the need for more storage and processing power. Virtual and cloud computing will be a method for dentists to minimize costs and maximize computer efficiency in the near future. This article will provide some useful information on current uses of cloud computing.

Virtual Resting Pd/Pa From Coronary Angiography and Blood Flow Modelling: Diagnostic Performance Against Fractional Flow Reserve.

Science.gov (United States)

Papafaklis, Michail I; Muramatsu, Takashi; Ishibashi, Yuki; Bourantas, Christos V; Fotiadis, Dimitrios I; Brilakis, Emmanouil S; Garcia-Garcia, Héctor M; Escaned, Javier; Serruys, Patrick W; Michalis, Lampros K

2018-03-01

Fractional flow reserve (FFR) has been established as a useful diagnostic tool. The distal coronary pressure to aortic pressure (Pd/Pa) ratio at rest is a simpler physiologic index but also requires the use of the pressure wire, whereas recently proposed virtual functional indices derived from coronary imaging require complex blood flow modelling and/or are time-consuming. Our aim was to test the diagnostic performance of virtual resting Pd/Pa using routine angiographic images and a simple flow model. Three-dimensional quantitative coronary angiography (3D-QCA) was performed in 139 vessels (120 patients) with intermediate lesions assessed by FFR. The resting Pd/Pa for each lesion was assessed by computational fluid dynamics. The discriminatory power of virtual resting Pd/Pa against FFR (reference: ≤0.80) was high (area under the receiver operator characteristic curve [AUC]: 90.5% [95% CI: 85.4-95.6%]). Diagnostic accuracy, sensitivity and specificity for the optimal virtual resting Pd/Pa cut-off (≤0.94) were 84.9%, 90.4% and 81.6%, respectively. Virtual resting Pd/Pa demonstrated superior performance (pvirtual resting Pd/Pa and FFR (r=0.69, pVirtual resting Pd/Pa using routine angiographic data and a simple flow model provides fast functional assessment of coronary lesions without requiring the pressure-wire and hyperaemia induction. The high diagnostic performance of virtual resting Pd/Pa for predicting FFR shows promise for using this simple/fast virtual index in clinical practice. Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

Kinematic evaluation of virtual walking trajectories.

Science.gov (United States)

Cirio, Gabriel; Olivier, Anne-Hélène; Marchal, Maud; Pettré, Julien

2013-04-01

Virtual walking, a fundamental task in Virtual Reality (VR), is greatly influenced by the locomotion interface being used, by the specificities of input and output devices, and by the way the virtual environment is represented. No matter how virtual walking is controlled, the generation of realistic virtual trajectories is absolutely required for some applications, especially those dedicated to the study of walking behaviors in VR, navigation through virtual places for architecture, rehabilitation and training. Previous studies focused on evaluating the realism of locomotion trajectories have mostly considered the result of the locomotion task (efficiency, accuracy) and its subjective perception (presence, cybersickness). Few focused on the locomotion trajectory itself, but in situation of geometrically constrained task. In this paper, we study the realism of unconstrained trajectories produced during virtual walking by addressing the following question: did the user reach his destination by virtually walking along a trajectory he would have followed in similar real conditions? To this end, we propose a comprehensive evaluation framework consisting on a set of trajectographical criteria and a locomotion model to generate reference trajectories. We consider a simple locomotion task where users walk between two oriented points in space. The travel path is analyzed both geometrically and temporally in comparison to simulated reference trajectories. In addition, we demonstrate the framework over a user study which considered an initial set of common and frequent virtual walking conditions, namely different input devices, output display devices, control laws, and visualization modalities. The study provides insight into the relative contributions of each condition to the overall realism of the resulting virtual trajectories.

Virtualization for the LHCb Online system

International Nuclear Information System (INIS)

Bonaccorsi, Enrico; Brarda, Loic; Moine, Gary; Neufeld, Niko

2011-01-01

Virtualization has long been advertised by the IT-industry as a way to cut down cost, optimise resource usage and manage the complexity in large data-centers. The great number and the huge heterogeneity of hardware, both industrial and custom-made, has up to now led to reluctance in the adoption of virtualization in the IT infrastructure of large experiment installations. Our experience in the LHCb experiment has shown that virtualization improves the availability and the manageability of the whole system. We have done an evaluation of available hypervisors / virtualization solutions and find that the Microsoft HV technology provides a high level of maturity and flexibility for our purpose. We present the results of these comparison tests, describing in detail, the architecture of our virtualization infrastructure with a special emphasis on the security for services visible to the outside world. Security is achieved by a sophisticated combination of VLANs, firewalls and virtual routing - the cost and benefits of this solution are analysed. We have adapted our cluster management tools, notably Quattor, for the needs of virtual machines and this allows us to migrate smoothly services on physical machines to the virtualized infrastructure. The procedures for migration will also be described. In the final part of the document we describe our recent R and D activities aiming to replacing the SAN-backend for the virtualization by a cheaper iSCSI solution - this will allow to move all servers and related services to the virtualized infrastructure, excepting the ones doing hardware control via non-commodity PCI plugin cards.

Virtual corporations, enterprise and organisation

Directory of Open Access Journals (Sweden)

Carmen RÃDUT

2009-06-01

Full Text Available Virtual organisation is a strategic paradigm that is centred on the use of information and ICT to create value. Virtual organisation is presented as a metamanagement strategy that has application in all value oriented organisations. Within the concept of Virtual organisation, the business model is an ICT based construct that bridges and integrates enterprise strategic and operational concerns. Firms try to ameliorate the impacts of risk and product complexity by forming alliances and partnerships with others to spread the risk of new products and new ventures and to increase organisational competence. The result is a networked virtual organization.

Playful mediation and virtual sociality

Directory of Open Access Journals (Sweden)

Sihem NAJJAR

2010-01-01

Full Text Available As a space of sociability, virtual games, especially online role playing games, allow us to capture the interest of the playfulness in social life, but they are means by which users are able to experiment their relationship to others. The virtual games as a mediation device, constitute a "pretext" to forge friendships, develop love relationships, improve language skills, discover other cultures, etc. Based on a sociological survey of Tunisian Internet users (both sexes fans of virtual games we try to show how playful mediation is producing a multifaceted virtual sociality inherent in our contemporary societies.

DEVELOPMENT OF A VIRTUAL MUSEUM INCLUDING A 4D PRESENTATION OF BUILDING HISTORY IN VIRTUAL REALITY

OpenAIRE

T. P. Kersten; F. Tschirschwitz; S. Deggim

2017-01-01

In the last two decades the definition of the term “virtual museum” changed due to rapid technological developments. Using today’s available 3D technologies a virtual museum is no longer just a presentation of collections on the Internet or a virtual tour of an exhibition using panoramic photography. On one hand, a virtual museum should enhance a museum visitor's experience by providing access to additional materials for review and knowledge deepening either before or after the real ...

Physical and virtual water transfers for regional water stress alleviation in China.

Science.gov (United States)

Zhao, Xu; Liu, Junguo; Liu, Qingying; Tillotson, Martin R; Guan, Dabo; Hubacek, Klaus

2015-01-27

Water can be redistributed through, in physical terms, water transfer projects and virtually, embodied water for the production of traded products. Here, we explore whether such water redistributions can help mitigate water stress in China. This study, for the first time to our knowledge, both compiles a full inventory for physical water transfers at a provincial level and maps virtual water flows between Chinese provinces in 2007 and 2030. Our results show that, at the national level, physical water flows because of the major water transfer projects amounted to 4.5% of national water supply, whereas virtual water flows accounted for 35% (varies between 11% and 65% at the provincial level) in 2007. Furthermore, our analysis shows that both physical and virtual water flows do not play a major role in mitigating water stress in the water-receiving regions but exacerbate water stress for the water-exporting regions of China. Future water stress in the main water-exporting provinces is likely to increase further based on our analysis of the historical trajectory of the major governing socioeconomic and technical factors and the full implementation of policy initiatives relating to water use and economic development. Improving water use efficiency is key to mitigating water stress, but the efficiency gains will be largely offset by the water demand increase caused by continued economic development. We conclude that much greater attention needs to be paid to water demand management rather than the current focus on supply-oriented management.

Virtual Prototyping at CERN

Science.gov (United States)

Gennaro, Silvano De

The VENUS (Virtual Environment Navigation in the Underground Sites) project is probably the largest Virtual Reality application to Engineering design in the world. VENUS is just over one year old and offers a fully immersive and stereoscopic "flythru" of the LHC pits for the proposed experiments, including the experimental area equipment and the surface models that are being prepared for a territorial impact study. VENUS' Virtual Prototypes are an ideal replacement for the wooden models traditionally build for the past CERN machines, as they are generated directly from the EUCLID CAD files, therefore they are totally reliable, they can be updated in a matter of minutes, and they allow designers to explore them from inside, in a one-to-one scale. Navigation can be performed on the computer screen, on a stereoscopic large projection screen, or in immersive conditions, with an helmet and 3D mouse. By using specialised collision detection software, the computer can find optimal paths to lower each detector part into the pits and position it to destination, letting us visualize the whole assembly probess. During construction, these paths can be fed to a robot controller, which can operate the bridge cranes and build LHC almost without human intervention. VENUS is currently developing a multiplatform VR browser that will let the whole HEP community access LHC's Virtual Protoypes over the web. Many interesting things took place during the conference on Virtual Reality. For more information please refer to the Virtual Reality section.

Chemical-Based Formulation Design: Virtual Experimentation

DEFF Research Database (Denmark)

Conte, Elisa; Gani, Rafiqul

This paper presents a software, the virtual Product-Process Design laboratory (virtual PPD-lab) and the virtual experimental scenarios for design/verification of consumer oriented liquid formulated products where the software can be used. For example, the software can be employed for the design......, the additives and/or their mixtures (formulations). Therefore, the experimental resources can focus on a few candidate product formulations to find the best product. The virtual PPD-lab allows various options for experimentations related to design and/or verification of the product. For example, the selection...... design, model adaptation). All of the above helps to perform virtual experiments by blending chemicals together and observing their predicted behaviour. The paper will highlight the application of the virtual PPD-lab in the design and/or verification of different consumer products (paint formulation...

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.

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....

The Virtual Shopping Experience: using virtual presence to motivate online shopping

Directory of Open Access Journals (Sweden)

Carolyn Chin

2005-11-01

Full Text Available Online shopping has thus far tended to be a niche business – highly successful in selling digital products such as shares, software and, increasingly, music and films, it has been less successful in persuading the purchasers of ‘traditional’ goods such as cars, clothes, toiletries, or household appliances to forsake their physical retailers and move into cyberspace. In this wide-ranging review paper we investigate the issue of the virtual experience – endeavouring to understand what is needed for a successful ‘shopping experience’ online and what the possible obstacles or pitfalls along the way might be. We initially introduce the concepts of virtual presence (the sense of ‘being there’ and virtual reality, discussing the possible roles both can play in providing a solution to the problem of effective online shopping. We then consider the Experience Economy, a concept which encapsulates many of the issues related to the problem of online shopping and which suggests ways in which online retailers can enhance the effectiveness of their sites by means of a virtual ‘experience’. Having set the scene for online shopping, we discuss eTailing today in terms of direct product experience and the opportunities which cyber-shopping offers to replicate this process. Finally, we identify some of the possibilities and problems of online shopping today, illustrating the current status of virtual presence in retailing with two micro-cases of success and failure.

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...

Time-Predictable Virtual Memory

DEFF Research Database (Denmark)

Puffitsch, Wolfgang; Schoeberl, Martin

2016-01-01

Virtual memory is an important feature of modern computer architectures. For hard real-time systems, memory protection is a particularly interesting feature of virtual memory. However, current memory management units are not designed for time-predictability and therefore cannot be used...... in such systems. This paper investigates the requirements on virtual memory from the perspective of hard real-time systems and presents the design of a time-predictable memory management unit. Our evaluation shows that the proposed design can be implemented efficiently. The design allows address translation...... and address range checking in constant time of two clock cycles on a cache miss. This constant time is in strong contrast to the possible cost of a miss in a translation look-aside buffer in traditional virtual memory organizations. Compared to a platform without a memory management unit, these two additional...

Using serious games and virtual worlds in pesticides transport teaching

Science.gov (United States)

Payraudeau, Sylvain; Alvarez-Zaldivar, Pablo; van Dijk, Paul; Imfeld, Gwenaël

2017-04-01

the degradation effect in complex agricultural catchments receiving pesticides. We anticipate our e-learning teaching unit based on serious game and virtual catchments will help future scientists and stakeholders to better understand and manage pesticides transport within catchments.

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....

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...

Virtual reality in pediatric psychology

OpenAIRE

Parsons, T. D.; Riva, G.; Parsons, S. J.; Mantovani, F.; Newbutt, N.; Lin, L.; Venturini, E.; Hall, T.

2017-01-01

Virtual reality technologies allow for controlled simulations of affectively engaging background narratives. These virtual environments offer promise for enhancing emotionally relevant experiences and social interactions. Within this context virtual reality can allow instructors, therapists, neuropsychologists, and service providers to offer safe, repeatable, and diversifiable interventions that can benefit assessments and learning in both typically developing children and children with disab...

Gender differences in current received during transcranial electrical stimulation

Directory of Open Access Journals (Sweden)

Michael eRussell

2014-08-01

Full Text Available Low current transcranial electrical stimulation is an effective but somewhat inconsistent tool for augmenting neuromodulation. In this study, we used 3D MRI guided electrical transcranial stimulation (GETS modeling to estimate the range of current intensities received at cortical brain tissues. Combined T1, T2, Proton Density MRIs from 24 adult subjects (12 male and 12 female were modeled with virtual electrodes placed at F3, F4, C3 and C4. Two sizes of electrodes 20 mm round and 50 x 45 mm square were examined at 0.5, 1 and 2 mA input currents. The intensity of current received was sampled in a one centimeter sphere placed at the cortex directly under each scalp electrode. There was a tenfold range in the current received by individuals. A large gender difference was observed with female subjects receiving significantly less current at targeted parietal cortex than male subjects when stimulated at identical current levels (P <0.05. Larger electrodes delivered somewhat larger amounts of current then the smaller ones (P <0.01. Electrodes in the frontal regions delivered less current than those in the parietal region (P<0.05. There were large individual differences in current levels the subjects received. Analysis of the cranial bone showed that the gender difference and the frontal parietal differences are due to differences in cranial bone. Males have more cancellous parietal bone and females more dense parietal bone (p<0.01. These differences should be considered when planning transcranial electrical stimulation studies and call into question earlier reports of gender differences due to hormonal influences.

Large deviations for Markov chains in the positive quadrant

Energy Technology Data Exchange (ETDEWEB)

Borovkov, A A; Mogul' skii, A A [S.L. Sobolev Institute for Mathematics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation)

2001-10-31

The paper deals with so-called N-partially space-homogeneous time-homogeneous Markov chains X(y,n), n=0,1,2,..., X(y,0)=y, in the positive quadrant. These Markov chains are characterized by the following property of the transition probabilities P(y,A)=P(X(y,1) element of A): for some N{>=}0 the measure P(y,dx) depends only on x{sub 2}, y{sub 2}, and x{sub 1}-y{sub 1} in the domain x{sub 1}>N, y{sub 1}>N, and only on x{sub 1}, y{sub 1}, and x{sub 2}-y{sub 2} in the domain x{sub 2}>N, y{sub 2}>N. For such chains the asymptotic behaviour is found for a fixed set B as s{yields}{infinity}, |x|{yields}{infinity}, and n{yields}{infinity}. Some other conditions on the growth of parameters are also considered, for example, |x-y|{yields}{infinity}, |y|{yields}{infinity}. A study is made of the structure of the most probable trajectories, which give the main contribution to this asymptotics, and a number of other results pertaining to the topic are established. Similar results are obtained for the narrower class of 0-partially homogeneous ergodic chains under less restrictive moment conditions on the transition probabilities P(y,dx). Moreover, exact asymptotic expressions for the probabilities P(X(0,n) element of x+B) are found for 0-partially homogeneous ergodic chains under some additional conditions. The interest in partially homogeneous Markov chains in positive octants is due to the mathematical aspects (new and interesting problems arise in the framework of general large deviation theory) as well as applied issues, for such chains prove to be quite accurate mathematical models for numerous basic types of queueing and communication networks such as the widely known Jackson networks, polling systems, or communication networks associated with the ALOHA algorithm. There is a vast literature dealing with the analysis of these objects. The present paper is an attempt to find the extent to which an asymptotic analysis is possible for Markov chains of this type in their general

A Deuteration Survey of Starless Clumps in GemOB1 and the First Quadrant

Science.gov (United States)

Henrici, Andrew; Shirley, Yancy L.; Svoboda, Brian

2018-01-01

One very strong chemical process in star-forming regions is the fractionation of deuterium in molecules, which results in an increase in the deuterium ratio many orders of magnitude over the ISM [D]/[H] ratio and provides a chemical probe of cold, dense regions. Recent maps of dust continuum emission at (sub)millimeter wavelengths have identified tens of thousands of dense clumps of gas and dust. By comparing these regions to infrared and radio surveys, we have identified starless clump candidates which have no evidence for embedded star formation. These objects represent the earliest phase of star formation throughout the Milky Way. One benefit of the Milky Way surveys is that it is also possible to study the chemistry of entire core and clump populations within a single cloud. We used the 10m Heinrich Hertz Submillimeter Telescope to survey starless clump candidates in the First Quadrant identified from the Bolocam Galactic Plane Survey 1.1 mm continuum in the deuterated molecular transitions of DCO+ 3-2 and N2D+ 3-2. We also survey the entire clump population of the Gemini OB1 molecular cloud. In both surveys, we compared detection statistics and compare deuteration fraction to physical properties of the clumps and their evolutionary stage. High resolution ALMA observations of 9 starless clump candidates of the same lines are used to analyze how the cold deuterated gas is spatially distributed in these clumps.

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...

Virtual Reality Hysteroscopy

Science.gov (United States)

Levy

1996-08-01

New interactive computer technologies are having a significant influence on medical education, training, and practice. The newest innovation in computer technology, virtual reality, allows an individual to be immersed in a dynamic computer-generated, three-dimensional environment and can provide realistic simulations of surgical procedures. A new virtual reality hysteroscope passes through a sensing device that synchronizes movements with a three-dimensional model of a uterus. Force feedback is incorporated into this model, so the user actually experiences the collision of an instrument against the uterine wall or the sensation of the resistance or drag of a resectoscope as it cuts through a myoma in a virtual environment. A variety of intrauterine pathologies and procedures are simulated, including hyperplasia, cancer, resection of a uterine septum, polyp, or myoma, and endometrial ablation. This technology will be incorporated into comprehensive training programs that will objectively assess hand-eye coordination and procedural skills. It is possible that by incorporating virtual reality into hysteroscopic training programs, a decrease in the learning curve and the number of complications presently associated with the procedures may be realized. Prospective studies are required to assess these potential benefits.

Electronic warfare receivers and receiving systems

CERN Document Server

Poisel, Richard A

2014-01-01

Receivers systems are considered the core of electronic warfare (EW) intercept systems. Without them, the fundamental purpose of such systems is null and void. This book considers the major elements that make up receiver systems and the receivers that go in them.This resource provides system design engineers with techniques for design and development of EW receivers for modern modulations (spread spectrum) in addition to receivers for older, common modulation formats. Each major module in these receivers is considered in detail. Design information is included as well as performance tradeoffs o

Virtualization for the LHCb experiment

International Nuclear Information System (INIS)

Bonaccorsi, E.; Brarda, L.; Chebbi, M.; Neufeld, N.; Sborzacci, F.

2012-01-01

The LHCb experiment, one of the 4 large particle detector at CERN, counts in its Online System more than 2000 servers and embedded systems. As a result of ever-increasing CPU performance in modern servers, many of the applications in the controls system are excellent candidates for virtualization technologies. We see virtualization as an approach to cut down cost, optimize resource usage and manage the complexity of the IT infrastructure of LHCb. Recently we have added a Kernel Virtual Machine (KVM) cluster based on Red Hat Enterprise Virtualization for Servers (RHEV) complementary to the existing Hyper-V cluster devoted only to the virtualization of the windows guests. This paper describes the architecture of our solution based on KVM and RHEV as along with its integration with the existing Hyper-V infrastructure and the Quattor cluster management tools and in particular how we use to run controls applications on a virtualized infrastructure. We present performance results of both the KVM and Hyper-V solutions, problems encountered and a description of the management tools developed for the integration with the Online cluster and LHCb SCADA control system based on PVSS. (authors)

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...

Virtual reality training improves balance function.

Science.gov (United States)

Mao, Yurong; Chen, Peiming; Li, Le; Huang, Dongfeng

2014-09-01

Virtual reality is a new technology that simulates a three-dimensional virtual world on a computer and enables the generation of visual, audio, and haptic feedback for the full immersion of users. Users can interact with and observe objects in three-dimensional visual space without limitation. At present, virtual reality training has been widely used in rehabilitation therapy for balance dysfunction. This paper summarizes related articles and other articles suggesting that virtual reality training can improve balance dysfunction in patients after neurological diseases. When patients perform virtual reality training, the prefrontal, parietal cortical areas and other motor cortical networks are activated. These activations may be involved in the reconstruction of neurons in the cerebral cortex. Growing evidence from clinical studies reveals that virtual reality training improves the neurological function of patients with spinal cord injury, cerebral palsy and other neurological impairments. These findings suggest that virtual reality training can activate the cerebral cortex and improve the spatial orientation capacity of patients, thus facilitating the cortex to control balance and increase motion function.

Virtual reality training improves balance function