Validation of intermediate end points in cancer research.

Science.gov (United States)

Schatzkin, A; Freedman, L S; Schiffman, M H; Dawsey, S M

1990-11-21

Investigations using intermediate end points as cancer surrogates are quicker, smaller, and less expensive than studies that use malignancy as the end point. We present a strategy for determining whether a given biomarker is a valid intermediate end point between an exposure and incidence of cancer. Candidate intermediate end points may be selected from case series, ecologic studies, and animal experiments. Prospective cohort and sometimes case-control studies may be used to quantify the intermediate end point-cancer association. The most appropriate measure of this association is the attributable proportion. The intermediate end point is a valid cancer surrogate if the attributable proportion is close to 1.0, but not if it is close to 0. Usually, the attributable proportion is close to neither 1.0 nor 0; in this case, valid surrogacy requires that the intermediate end point mediate an established exposure-cancer relation. This would in turn imply that the exposure effect would vanish if adjusted for the intermediate end point. We discuss the relative advantages of intervention and observational studies for the validation of intermediate end points. This validation strategy also may be applied to intermediate end points for adverse reproductive outcomes and chronic diseases other than cancer.

A time domain inverse dynamic method for the end point tracking control of a flexible manipulator

Science.gov (United States)

Kwon, Dong-Soo; Book, Wayne J.

1991-01-01

The inverse dynamic equation of a flexible manipulator was solved in the time domain. By dividing the inverse system equation into the causal part and the anticausal part, we calculated the torque and the trajectories of all state variables for a given end point trajectory. The interpretation of this method in the frequency domain was explained in detail using the two-sided Laplace transform and the convolution integral. The open loop control of the inverse dynamic method shows an excellent result in simulation. For real applications, a practical control strategy is proposed by adding a feedback tracking control loop to the inverse dynamic feedforward control, and its good experimental performance is presented.

Familiar trajectories facilitate the interpretation of physical forces when intercepting a moving target.

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Mijatović, Antonija; La Scaleia, Barbara; Mercuri, Nicola; Lacquaniti, Francesco; Zago, Myrka

2014-12-01

Familiarity with the visual environment affects our expectations about the objects in a scene, aiding in recognition and interaction. Here we tested whether the familiarity with the specific trajectory followed by a moving target facilitates the interpretation of the effects of underlying physical forces. Participants intercepted a target sliding down either an inclined plane or a tautochrone. Gravity accelerated the target by the same amount in both cases, but the inclined plane represented a familiar trajectory whereas the tautochrone was unfamiliar to the participants. In separate sessions, the gravity field was consistent with either natural gravity or artificial reversed gravity. Target motion was occluded from view over the last segment. We found that the responses in the session with unnatural forces were systematically delayed relative to those with natural forces, but only for the inclined plane. The time shift is consistent with a bias for natural gravity, in so far as it reflects an a priori expectation that a target not affected by natural forces will arrive later than one accelerated downwards by gravity. Instead, we did not find any significant time shift with unnatural forces in the case of the tautochrone. We argue that interception of a moving target relies on the integration of the high-level cue of trajectory familiarity with low-level cues related to target kinematics.

Zero-point energy constraint in quasi-classical trajectory calculations.

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Xie, Zhen; Bowman, Joel M

2006-04-27

A method to constrain the zero-point energy in quasi-classical trajectory calculations is proposed and applied to the Henon-Heiles system. The main idea of this method is to smoothly eliminate the coupling terms in the Hamiltonian as the energy of any mode falls below a specified value.

End-point sharpness in thermometric titrimetry.

Science.gov (United States)

Tyrrell, H J

1967-07-01

It is shown that the sharpness of an end-point in a thermometric titration where the simple reaction A + B right harpoon over left harpoon AB takes place, depends on Kc(A') where K is the equilibrium constant for the reaction, and c(A') is the total concentration of the titrand (A) in the reaction mixture. The end-point is sharp if, (i) the enthalpy change in the reaction is not negligible, and (ii) Kc(A') > 10(3). This shows that it should, for example, be possible to titrate 0.1 M acid, pK(A) = 10, using a thennometric end-point. Some aspects of thermometric titrimetry when Kc(A') < 10(3) are also considered.

Human arm stiffness and equilibrium-point trajectory during multi-joint movement.

Science.gov (United States)

Gomi, H; Kawato, M

1997-03-01

By using a newly designed high-performance manipulandum and a new estimation algorithm, we measured human multi-joint arm stiffness parameters during multi-joint point-to-point movements on a horizontal plane. This manipulandum allows us to apply a sufficient perturbation to subject's arm within a brief period during movement. Arm stiffness parameters were reliably estimated using a new algorithm, in which all unknown structural parameters could be estimated independent of arm posture (i.e., constant values under any arm posture). Arm stiffness during transverse movement was considerably greater than that during corresponding posture, but not during a longitudinal movement. Although the ratios of elbow, shoulder, and double-joint stiffness were varied in time, the orientation of stiffness ellipses during the movement did not change much. Equilibrium-point trajectories that were predicted from measured stiffness parameters and actual trajectories were slightly sinusoidally curved in Cartesian space and their velocity profiles were quite different from the velocity profiles of actual hand trajectories. This result contradicts the hypothesis that the brain does not take the dynamics into account in movement control depending on the neuromuscular servo mechanism; rather, it implies that the brain needs to acquire some internal models of controlled objects.

Managing Contextual Complexity in an Experiential Learning Course: A Dynamic Systems Approach through the Identification of Turning Points in Students' Emotional Trajectories

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Gloria Nogueiras

2017-05-01

Full Text Available This study adopts a dynamic systems approach to investigate how individuals successfully manage contextual complexity. To that end, we tracked individuals' emotional trajectories during a challenging training course, seeking qualitative changes–turning points—and we tested their relationship with the perceived complexity of the training. The research context was a 5-day higher education course based on process-oriented experiential learning, and the sample consisted of 17 students. The students used a five-point Likert scale to rate the intensity of 16 emotions and the complexity of the training on 8 measurement points. Monte Carlo permutation tests enabled to identify 30 turning points in the 272 emotional trajectories analyzed (17 students * 16 emotions each. 83% of the turning points indicated a change of pattern in the emotional trajectories that consisted of: (a increasingly intense positive emotions or (b decreasingly intense negative emotions. These turning points also coincided with particularly complex periods in the training as perceived by the participants (p = 0.003, and p = 0.001 respectively. The relationship between positively-trended turning points in the students' emotional trajectories and the complexity of the training may be interpreted as evidence of a successful management of the cognitive conflict arising from the clash between the students' prior ways of meaning-making and the challenging demands of the training. One of the strengths of this study is that it provides a relatively simple procedure for identifying turning points in developmental trajectories, which can be applied to various longitudinal experiences that are very common in educational and developmental contexts. Additionally, the findings contribute to sustaining that the assumption that complex contextual demands lead unfailingly to individuals' learning is incomplete. Instead, it is how individuals manage complexity which may or may not lead to

Expert judgments about transient climate response to alternative future trajectories of radiative forcing.

Science.gov (United States)

Zickfeld, Kirsten; Morgan, M Granger; Frame, David J; Keith, David W

2010-07-13

There is uncertainty about the response of the climate system to future trajectories of radiative forcing. To quantify this uncertainty we conducted face-to-face interviews with 14 leading climate scientists, using formal methods of expert elicitation. We structured the interviews around three scenarios of radiative forcing stabilizing at different levels. All experts ranked "cloud radiative feedbacks" as contributing most to their uncertainty about future global mean temperature change, irrespective of the specified level of radiative forcing. The experts disagreed about the relative contribution of other physical processes to their uncertainty about future temperature change. For a forcing trajectory that stabilized at 7 Wm(-2) in 2200, 13 of the 14 experts judged the probability that the climate system would undergo, or be irrevocably committed to, a "basic state change" as > or =0.5. The width and median values of the probability distributions elicited from the different experts for future global mean temperature change under the specified forcing trajectories vary considerably. Even for a moderate increase in forcing by the year 2050, the medians of the elicited distributions of temperature change relative to 2000 range from 0.8-1.8 degrees C, and some of the interquartile ranges do not overlap. Ten of the 14 experts estimated that the probability that equilibrium climate sensitivity exceeds 4.5 degrees C is > 0.17, our interpretation of the upper limit of the "likely" range given by the Intergovernmental Panel on Climate Change. Finally, most experts anticipated that over the next 20 years research will be able to achieve only modest reductions in their degree of uncertainty.

Most probable trajectory of a muon in a scattering medium, when input and output trajectories are known

Energy Technology Data Exchange (ETDEWEB)

Benton, Christopher J., E-mail: cjb30@bath.ac.uk [Department of Electronic and Electrical Engineering, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Smith, Nathan D. [Department of Electronic and Electrical Engineering, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Quillin, Stephen J.; Steer, Christopher A. [AWE, Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom)

2012-11-21

Tomographic imaging using cosmic ray muons has a range of applications including homeland security and geological imaging. To this end, we have developed a technique to calculate the most probable muon trajectory through a scattering material, given its measured entry and exit trajectories. This method has the potential to improve tomographic algorithms, in particular by replacing the muon paths assumed by the Point Of Closest Approach (POCA) method, with more realistic paths. These paths can be calculated for arbitary matter distributions, rather than just the point scatterers assumed by POCA.

Automatic Generation of Indoor Navigable Space Using a Point Cloud and its Scanner Trajectory

Science.gov (United States)

Staats, B. R.; Diakité, A. A.; Voûte, R. L.; Zlatanova, S.

2017-09-01

Automatic generation of indoor navigable models is mostly based on 2D floor plans. However, in many cases the floor plans are out of date. Buildings are not always built according to their blue prints, interiors might change after a few years because of modified walls and doors, and furniture may be repositioned to the user's preferences. Therefore, new approaches for the quick recording of indoor environments should be investigated. This paper concentrates on laser scanning with a Mobile Laser Scanner (MLS) device. The MLS device stores a point cloud and its trajectory. If the MLS device is operated by a human, the trajectory contains information which can be used to distinguish different surfaces. In this paper a method is presented for the identification of walkable surfaces based on the analysis of the point cloud and the trajectory of the MLS scanner. This method consists of several steps. First, the point cloud is voxelized. Second, the trajectory is analysing and projecting to acquire seed voxels. Third, these seed voxels are generated into floor regions by the use of a region growing process. By identifying dynamic objects, doors and furniture, these floor regions can be modified so that each region represents a specific navigable space inside a building as a free navigable voxel space. By combining the point cloud and its corresponding trajectory, the walkable space can be identified for any type of building even if the interior is scanned during business hours.

End points and assessments in esthetic dental treatment.

Science.gov (United States)

Ishida, Yuichi; Fujimoto, Keiko; Higaki, Nobuaki; Goto, Takaharu; Ichikawa, Tetsuo

2015-10-01

There are two key considerations for successful esthetic dental treatments. This article systematically describes the two key considerations: the end points of esthetic dental treatments and assessments of esthetic outcomes, which are also important for acquiring clinical skill in esthetic dental treatments. The end point and assessment of esthetic dental treatment were discussed through literature reviews and clinical practices. Before designing a treatment plan, the end point of dental treatment should be established. The section entitled "End point of esthetic dental treatment" discusses treatments for maxillary anterior teeth and the restoration of facial profile with prostheses. The process of assessing treatment outcomes entitled "Assessments of esthetic dental treatment" discusses objective and subjective evaluation methods. Practitioners should reach an agreement regarding desired end points with patients through medical interviews, and continuing improvements and developments of esthetic assessments are required to raise the therapeutic level of esthetic dental treatments. Copyright © 2015 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

End-point impedance measurements across dominant and nondominant hands and robotic assistance with directional damping.

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Erden, Mustafa Suphi; Billard, Aude

2015-06-01

The goal of this paper is to perform end-point impedance measurements across dominant and nondominant hands while doing airbrush painting and to use the results for developing a robotic assistance scheme. We study airbrush painting because it resembles in many ways manual welding, a standard industrial task. The experiments are performed with the 7 degrees of freedom KUKA lightweight robot arm. The robot is controlled in admittance using a force sensor attached at the end-point, so as to act as a free-mass and be passively guided by the human. For impedance measurements, a set of nine subjects perform 12 repetitions of airbrush painting, drawing a straight-line on a cartoon horizontally placed on a table, while passively moving the airbrush mounted on the robot's end-point. We measure hand impedance during the painting task by generating sudden and brief external forces with the robot. The results show that on average the dominant hand displays larger impedance than the nondominant in the directions perpendicular to the painting line. We find the most significant difference in the damping values in these directions. Based on this observation, we develop a "directional damping" scheme for robotic assistance and conduct a pilot study with 12 subjects to contrast airbrush painting with and without robotic assistance. Results show significant improvement in precision with both dominant and nondominant hands when using robotic assistance.

Impact Points and Their Effect on Trajectory in Soccer

Directory of Open Access Journals (Sweden)

Kaoru Kimachi

2018-02-01

Full Text Available The kick skill and its analysis are important in Soccer. To detect impact point by using virtual impact model is aim of this study. The virtual impact model was made as a surface composed of virtual markers. As the result, mean coordinate values of impact point were below; straight (Lateral: −24.0 ± 5.6 mm, Horizontal: 152.7 ± 8.4 mm, Vertical: 52.3 ± 4.0 mm, curve (Lateral: −35.6 ± 4.8 mm, Horizontal: 151.6 ± 13.7 mm, Vertical: 47.5 ± 5.2 mm, knuckle (Lateral: −33.3 ± 9.0 mm, Horizontal: 140.8 ± 10.7 mm, Vertical: 52.1 ± 2.7 mm. According to comparison of coordinate value of each trial, mean point of straight was near the center line of foot on instep, mean point of curve was located on inside of foot, mean point of knuckle was near the foot joint. We revealed difference of impact point and showed trajectory of impact point.

Static end-expiratory and dynamic forced expiratory tracheal collapse in COPD

International Nuclear Information System (INIS)

O'Donnell, C.R.; Bankier, A.A.; O'Donnell, D.H.; Loring, S.H.; Boiselle, P.M.

2014-01-01

Aim: To determine the range of tracheal collapse at end-expiration among chronic obstructive pulmonary disease (COPD) patients and to compare the extent of tracheal collapse between static end-expiratory and dynamic forced-expiratory multidetector-row computed tomography (MDCT). Materials and methods: After institutional review board approval and obtaining informed consent, 67 patients meeting the National Heart, Lung, and Blood Institute (NHLBI)/World Health Organization (WHO) Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria for COPD were sequentially imaged using a 64-detector-row CT machine at end-inspiration, during forced expiration, and at end-expiration. Standardized respiratory coaching and spirometric monitoring were employed. Mean percentage tracheal collapse at end-expiration and forced expiration were compared using correlation analysis, and the power of end-expiratory cross-sectional area to predict excessive forced-expiratory tracheal collapse was computed following construction of receiver operating characteristic (ROC) curves. Results: Mean percentage expiratory collapse among COPD patients was 17 ± 18% at end-expiration compared to 62 ± 16% during forced expiration. Over the observed range of end-expiratory tracheal collapse (approximately 10–50%), the positive predictive value of end-expiratory collapse to predict excessive (≥80%) forced expiratory tracheal collapse was <0.3. Conclusion: COPD patients demonstrate a wide range of end-expiratory tracheal collapse. The magnitude of static end-expiratory tracheal collapse does not predict excessive dynamic expiratory tracheal collapse

End points for adjuvant therapy trials: has the time come to accept disease-free survival as a surrogate end point for overall survival?

Science.gov (United States)

Gill, Sharlene; Sargent, Daniel

2006-06-01

The intent of adjuvant therapy is to eradicate micro-metastatic residual disease following curative resection with the goal of preventing or delaying recurrence. The time-honored standard for demonstrating efficacy of new adjuvant therapies is an improvement in overall survival (OS). This typically requires phase III trials of large sample size with lengthy follow-up. With the intent of reducing the cost and time of completing such trials, there is considerable interest in developing alternative or surrogate end points. A surrogate end point may be employed as a substitute to directly assess the effects of an intervention on an already accepted clinical end point such as mortality. When used judiciously, surrogate end points can accelerate the evaluation of new therapies, resulting in the more timely dissemination of effective therapies to patients. The current review provides a perspective on the suitability and validity of disease-free survival (DFS) as an alternative end point for OS. Criteria for establishing surrogacy and the advantages and limitations associated with the use of DFS as a primary end point in adjuvant clinical trials and as the basis for approval of new adjuvant therapies are discussed.

Adaptive Trajectory Design

Data.gov (United States)

National Aeronautics and Space Administration — Adaptive Trajectory Design (ATD) is an original concept for quick and efficient end-to-end trajectory designs using proven piece-wise dynamical methods. With ongoing...

Direct dynamics trajectory study of the reaction of formaldehyde cation with D2: vibrational and zero-point energy effects on quasiclassical trajectories.

Science.gov (United States)

Liu, Jianbo; Song, Kihyung; Hase, William L; Anderson, Scott L

2005-12-22

Quasiclassical, direct dynamics trajectories have been used to study the reaction of formaldehyde cation with molecular hydrogen, simulating the conditions in an experimental study of H2CO+ vibrational effects on this reaction. Effects of five different H2CO+ modes were probed, and we also examined different approaches to treating zero-point energy in quasiclassical trajectories. The calculated absolute cross-sections are in excellent agreement with experiments, and the results provide insight into the reaction mechanism, product scattering behavior, and energy disposal, and how they vary with impact parameter and reactant state. The reaction is sharply orientation-dependent, even at high collision energies, and both trajectories and experiment find that H2CO+ vibration inhibits reaction. On the other hand, the trajectories do not reproduce the anomalously strong effect of nu2(+) (the CO stretch). The origin of the discrepancy and approaches for minimizing such problems in quasiclassical trajectories are discussed.

UO3 deactivation end point criteria

International Nuclear Information System (INIS)

Stefanski, L.D.

1994-01-01

The UO 3 Deactivation End Point Criteria are necessary to facilitate the transfer of the UO 3 Facility from the Office of Facility Transition and Management (EM-60) to the office of Environmental Restoration (EM-40). The criteria were derived from a logical process for determining end points for the systems and spaces at the UO 3 , Facility based on the objectives, tasks, and expected future uses pertinent to that system or space. Furthermore, the established criteria meets the intent and supports the draft guidance for acceptance criteria prepared by EM-40, open-quotes U.S. Department of Energy office of Environmental Restoration (EM-40) Decontamination and Decommissioning Guidance Document (Draft).close quotes For the UO 3 Facility, the overall objective of deactivation is to achieve a safe, stable and environmentally sound condition, suitable for an extended period, as quickly and economically as possible. Once deactivated, the facility is kept in its stable condition by means of a methodical surveillance and maintenance (S ampersand M) program, pending ultimate decontamination and decommissioning (D ampersand D). Deactivation work involves a range of tasks, such as removal of hazardous material, elimination or shielding of radiation fields, partial decontamination to permit access for inspection, installation of monitors and alarms, etc. it is important that the end point of each of these tasks be established clearly and in advance, for the following reasons: (1) End points must be such that the central element of the deactivation objective - to achieve stability - is unquestionably achieved. (2) Much of the deactivation work involves worker exposure to radiation or dangerous materials. This can be minimized by avoiding unnecessary work. (3) Each task is, in effect, competing for resources with other deactivation tasks and other facilities. By assuring that each task is appropriately bounded, DOE's overall resources can be used most fully and effectively

Real-time UAV trajectory generation using feature points matching between video image sequences

Science.gov (United States)

Byun, Younggi; Song, Jeongheon; Han, Dongyeob

2017-09-01

Unmanned aerial vehicles (UAVs), equipped with navigation systems and video capability, are currently being deployed for intelligence, reconnaissance and surveillance mission. In this paper, we present a systematic approach for the generation of UAV trajectory using a video image matching system based on SURF (Speeded up Robust Feature) and Preemptive RANSAC (Random Sample Consensus). Video image matching to find matching points is one of the most important steps for the accurate generation of UAV trajectory (sequence of poses in 3D space). We used the SURF algorithm to find the matching points between video image sequences, and removed mismatching by using the Preemptive RANSAC which divides all matching points to outliers and inliers. The inliers are only used to determine the epipolar geometry for estimating the relative pose (rotation and translation) between image sequences. Experimental results from simulated video image sequences showed that our approach has a good potential to be applied to the automatic geo-localization of the UAVs system

Design and force analysis of end-effector for plug seedling transplanter.

Science.gov (United States)

Jiang, Zhuohua; Hu, Yang; Jiang, Huanyu; Tong, Junhua

2017-01-01

Automatic transplanters have been very important in greenhouses since the popularization of seedling nurseries. End-effector development is a key technology for transplanting plug seedlings. Most existing end-effectors have problems with holding root plugs or releasing plugs. An efficient end-effector driven by a linear pneumatic cylinder was designed in this study, which could hold root plugs firmly and release plugs easily. This end-effector with four needles could clamp the plug simultaneously while the needles penetrate into the substrate. The depth and verticality of the needles could be adjusted conveniently for different seedling trays. The effectiveness of this end-effector was tested by a combinational trial examining three seedling nursery factors (the moisture content of the substrate, substrate bulk density and the volume proportion of substrate ingredients). Results showed that the total transplanting success rate for the end-effector was 100%, and the root plug harm rate was below 17%. A force measure system with tension and pressure transducers was installed on the designed end-effector. The adhesive force FL between the root plug and the cell of seedling trays and the extrusion force FK on the root plug were measured and analyzed. The results showed that all three variable factors and their interactions had significant effects on the extrusion force. Each factor had a significant effect on adhesive force. Additionally, it was found that the end-effector did not perform very well when the value of FK/FL was beyond the range of 5.99~8.67. This could provide a scientific basis for end-effector application in transplanting.

Control of force during rapid visuomotor force-matching tasks can be described by discrete time PID control algorithms.

Science.gov (United States)

Dideriksen, Jakob Lund; Feeney, Daniel F; Almuklass, Awad M; Enoka, Roger M

2017-08-01

Force trajectories during isometric force-matching tasks involving isometric contractions vary substantially across individuals. In this study, we investigated if this variability can be explained by discrete time proportional, integral, derivative (PID) control algorithms with varying model parameters. To this end, we analyzed the pinch force trajectories of 24 subjects performing two rapid force-matching tasks with visual feedback. Both tasks involved isometric contractions to a target force of 10% maximal voluntary contraction. One task involved a single action (pinch) and the other required a double action (concurrent pinch and wrist extension). 50,000 force trajectories were simulated with a computational neuromuscular model whose input was determined by a PID controller with different PID gains and frequencies at which the controller adjusted muscle commands. The goal was to find the best match between each experimental force trajectory and all simulated trajectories. It was possible to identify one realization of the PID controller that matched the experimental force produced during each task for most subjects (average index of similarity: 0.87 ± 0.12; 1 = perfect similarity). The similarities for both tasks were significantly greater than that would be expected by chance (single action: p = 0.01; double action: p = 0.04). Furthermore, the identified control frequencies in the simulated PID controller with the greatest similarities decreased as task difficulty increased (single action: 4.0 ± 1.8 Hz; double action: 3.1 ± 1.3 Hz). Overall, the results indicate that discrete time PID controllers are realistic models for the neural control of force in rapid force-matching tasks involving isometric contractions.

Steady and perturbed motion of a point vortex along a boundary with a circular cavity

Energy Technology Data Exchange (ETDEWEB)

Ryzhov, E.A., E-mail: ryzhovea@poi.dvo.ru [Pacific Oceanological Institute, FEB RAS, 43, Baltiyskaya Street, Vladivostok, 690041 (Russian Federation); Koshel, K.V., E-mail: kvkoshel@poi.dvo.ru [Pacific Oceanological Institute, FEB RAS, 43, Baltiyskaya Street, Vladivostok, 690041 (Russian Federation); Far Eastern Federal University, 8, Sukhanova Street, Vladivostok, 690950 (Russian Federation)

2016-02-22

The dynamics of a point vortex moving along a straight boundary with a circular cavity subjected to a background flow is investigated. Given the constant background flow, this configuration produces regular phase portraits of the vortex motion. These phase portraits are discriminated depending on the cavity's circular shape, and then the transition to chaos of the vortex motion is investigated given an oscillating perturbation superimposed on the background flow. Based on the steady-state vortex rotation, the forcing parameters that lead to effective destabilization of vortex trajectories are distinguished. We show that, provided the cavity aperture is relatively narrow, the periodic forcing superimposed on the background flow destabilizes the vortex trajectories very slightly. On the other hand, if the cavity aperture is relatively wide, the forcing can significantly destabilize vortex trajectories causing the majority of the trajectories, which would be closed without the forcing, to move towards infinity. - Highlights: • The dynamics of a point vortex moving along a straight boundary with a circular cavity is addressed. • Three phase portrait structures depending on the cavity's circular shape are singled out. • Forcing parameters that lead to effective destabilization of vortex trajectories are found.

Design and force analysis of end-effector for plug seedling transplanter.

Directory of Open Access Journals (Sweden)

Zhuohua Jiang

Full Text Available Automatic transplanters have been very important in greenhouses since the popularization of seedling nurseries. End-effector development is a key technology for transplanting plug seedlings. Most existing end-effectors have problems with holding root plugs or releasing plugs. An efficient end-effector driven by a linear pneumatic cylinder was designed in this study, which could hold root plugs firmly and release plugs easily. This end-effector with four needles could clamp the plug simultaneously while the needles penetrate into the substrate. The depth and verticality of the needles could be adjusted conveniently for different seedling trays. The effectiveness of this end-effector was tested by a combinational trial examining three seedling nursery factors (the moisture content of the substrate, substrate bulk density and the volume proportion of substrate ingredients. Results showed that the total transplanting success rate for the end-effector was 100%, and the root plug harm rate was below 17%. A force measure system with tension and pressure transducers was installed on the designed end-effector. The adhesive force FL between the root plug and the cell of seedling trays and the extrusion force FK on the root plug were measured and analyzed. The results showed that all three variable factors and their interactions had significant effects on the extrusion force. Each factor had a significant effect on adhesive force. Additionally, it was found that the end-effector did not perform very well when the value of FK/FL was beyond the range of 5.99~8.67. This could provide a scientific basis for end-effector application in transplanting.

Evaluation of use of MPAD trajectory tape and number of orbit points for orbiter mission thermal predictions

Science.gov (United States)

Vogt, R. A.

1979-01-01

The application of using the mission planning and analysis division (MPAD) common format trajectory data tape to predict temperatures for preflight and post flight mission analysis is presented and evaluated. All of the analyses utilized the latest Space Transportation System 1 flight (STS-1) MPAD trajectory tape, and the simplified '136 note' midsection/payload bay thermal math model. For the first 6.7 hours of the STS-1 flight profile, transient temperatures are presented for selected nodal locations with the current standard method, and the trajectory tape method. Whether the differences are considered significant or not depends upon the view point. Other transient temperature predictions are also presented. These results were obtained to investigate an initial concern that perhaps the predicted temperature differences between the two methods would not only be caused by the inaccuracies of the current method's assumed nominal attitude profile but also be affected by a lack of a sufficient number of orbit points in the current method. Comparison between 6, 12, and 24 orbit point parameters showed a surprising insensitivity to the number of orbit points.

Gran method for end point anticipation in monosegmented flow titration

Directory of Open Access Journals (Sweden)

Aquino Emerson V

2004-01-01

Full Text Available An automatic potentiometric monosegmented flow titration procedure based on Gran linearisation approach has been developed. The controlling program can estimate the end point of the titration after the addition of three or four aliquots of titrant. Alternatively, the end point can be determined by the second derivative procedure. In this case, additional volumes of titrant are added until the vicinity of the end point and three points before and after the stoichiometric point are used for end point calculation. The performance of the system was assessed by the determination of chloride in isotonic beverages and parenteral solutions. The system employs a tubular Ag2S/AgCl indicator electrode. A typical titration, performed according to the IUPAC definition, requires only 60 mL of sample and about the same volume of titrant (AgNO3 solution. A complete titration can be carried out in 1 - 5 min. The accuracy and precision (relative standard deviation of ten replicates are 2% and 1% for the Gran and 1% and 0.5% for the Gran/derivative end point determination procedures, respectively. The proposed system reduces the time to perform a titration, ensuring low sample and reagent consumption, and full automatic sampling and titrant addition in a calibration-free titration protocol.

The cislunar low-thrust trajectories via the libration point

Science.gov (United States)

Qu, Qingyu; Xu, Ming; Peng, Kun

2017-05-01

The low-thrust propulsion will be one of the most important propulsion in the future due to its large specific impulse. Different from traditional low-thrust trajectories (LTTs) yielded by some optimization algorithms, the gradient-based design methodology is investigated for LTTs in this paper with the help of invariant manifolds of LL1 point and Halo orbit near the LL1 point. Their deformations under solar gravitational perturbation are also presented to design LTTs in the restricted four-body model. The perturbed manifolds of LL1 point and its Halo orbit serve as the free-flight phase to reduce the fuel consumptions as much as possible. An open-loop control law is proposed, which is used to guide the spacecraft escaping from Earth or captured by Moon. By using a two-dimensional search strategy, the ON/OFF time of the low-thrust engine in the Earth-escaping and Moon-captured phases can be obtained. The numerical implementations show that the LTTs achieved in this paper are consistent with the one adopted by the SMART-1 mission.

Vectorization of a classical trajectory code on a floating point systems, Inc. Model 164 attached processor.

Science.gov (United States)

Kraus, Wayne A; Wagner, Albert F

1986-04-01

A triatomic classical trajectory code has been modified by extensive vectorization of the algorithms to achieve much improved performance on an FPS 164 attached processor. Extensive timings on both the FPS 164 and a VAX 11/780 with floating point accelerator are presented as a function of the number of trajectories simultaneously run. The timing tests involve a potential energy surface of the LEPS variety and trajectories with 1000 time steps. The results indicate that vectorization results in timing improvements on both the VAX and the FPS. For larger numbers of trajectories run simultaneously, up to a factor of 25 improvement in speed occurs between VAX and FPS vectorized code. Copyright © 1986 John Wiley & Sons, Inc.

Surrogate end points in clinical research: hazardous to your health.

Science.gov (United States)

Grimes, David A; Schulz, Kenneth F

2005-05-01

Surrogate end points in clinical research pose real danger. A surrogate end point is an outcome measure, commonly a laboratory test, that substitutes for a clinical event of true importance. Resistance to activated protein C, for example, has been used as a surrogate for venous thrombosis in women using oral contraceptives. Other examples of inappropriate surrogate end points in contraception include the postcoital test instead of pregnancy to evaluate new spermicides, breakage and slippage instead of pregnancy to evaluate condoms, and bone mineral density instead of fracture to assess the safety of depo-medroxyprogesterone acetate. None of these markers captures the effect of the treatment on the true outcome. A valid surrogate end point must both correlate with and accurately predict the outcome of interest. Although many surrogate markers correlate with an outcome, few have been shown to capture the effect of a treatment (for example, oral contraceptives) on the outcome (venous thrombosis). As a result, thousands of useless and misleading reports on surrogate end points litter the medical literature. New drugs have been shown to benefit a surrogate marker, but, paradoxically, triple the risk of death. Thousands of patients have died needlessly because of reliance on invalid surrogate markers. Researchers should avoid surrogate end points unless they have been validated; that requires at least one well done trial using both the surrogate and true outcome. The clinical maxim that "a difference to be a difference must make a difference" applies to research as well. Clinical research should focus on outcomes that matter.

Numerical study and ex vivo assessment of HIFU treatment time reduction through optimization of focal point trajectory

Science.gov (United States)

Grisey, A.; Yon, S.; Pechoux, T.; Letort, V.; Lafitte, P.

2017-03-01

Treatment time reduction is a key issue to expand the use of high intensity focused ultrasound (HIFU) surgery, especially for benign pathologies. This study aims at quantitatively assessing the potential reduction of the treatment time arising from moving the focal point during long pulses. In this context, the optimization of the focal point trajectory is crucial to achieve a uniform thermal dose repartition and avoid boiling. At first, a numerical optimization algorithm was used to generate efficient trajectories. Thermal conduction was simulated in 3D with a finite difference code and damages to the tissue were modeled using the thermal dose formula. Given an initial trajectory, the thermal dose field was first computed, then, making use of Pontryagin's maximum principle, the trajectory was iteratively refined. Several initial trajectories were tested. Then, an ex vivo study was conducted in order to validate the efficicency of the resulting optimized strategies. Single pulses were performed at 3MHz on fresh veal liver samples with an Echopulse and the size of each unitary lesion was assessed by cutting each sample along three orthogonal planes and measuring the dimension of the whitened area based on photographs. We propose a promising approach to significantly shorten HIFU treatment time: the numerical optimization algorithm was shown to provide a reliable insight on trajectories that can improve treatment strategies. The model must now be improved in order to take in vivo conditions into account and extensively validated.

Optical Tweezers-Based Measurements of Forces and Dynamics at Microtubule Ends.

Science.gov (United States)

Baclayon, Marian; Kalisch, Svenja-Marei; Hendel, Ed; Laan, Liedewij; Husson, Julien; Munteanu, E Laura; Dogterom, Marileen

2017-01-01

Microtubules are dynamic cytoskeletal polymers that polymerize and depolymerize while interacting with different proteins and structures within the cell. The highly regulated dynamic properties as well as the pushing and pulling forces generated by dynamic microtubule ends play important roles in processes such as in cell division. For instance, microtubule end-binding proteins are known to affect dramatically the dynamic properties of microtubules, and cortical dyneins are known to mediate pulling forces on microtubule ends. We discuss in this chapter our efforts to reconstitute these systems in vitro and mimic their interactions with structures within the cell using micro-fabricated barriers. Using an optical tweezers setup, we investigate the dynamics and forces of microtubules growing against functionalized barriers in the absence and presence of end-binding proteins and barrier-attached motor proteins. This setup allows high-speed as well as nanometer and piconewton resolution measurements on dynamic microtubules.

Spline Trajectory Algorithm Development: Bezier Curve Control Point Generation for UAVs

Science.gov (United States)

Howell, Lauren R.; Allen, B. Danette

2016-01-01

A greater need for sophisticated autonomous piloting systems has risen in direct correlation with the ubiquity of Unmanned Aerial Vehicle (UAV) technology. Whether surveying unknown or unexplored areas of the world, collecting scientific data from regions in which humans are typically incapable of entering, locating lost or wanted persons, or delivering emergency supplies, an unmanned vehicle moving in close proximity to people and other vehicles, should fly smoothly and predictably. The mathematical application of spline interpolation can play an important role in autopilots' on-board trajectory planning. Spline interpolation allows for the connection of Three-Dimensional Euclidean Space coordinates through a continuous set of smooth curves. This paper explores the motivation, application, and methodology used to compute the spline control points, which shape the curves in such a way that the autopilot trajectory is able to meet vehicle-dynamics limitations. The spline algorithms developed used to generate these curves supply autopilots with the information necessary to compute vehicle paths through a set of coordinate waypoints.

A step towards standardization: A method for end-point titer determination by fluorescence index of an automated microscope. End-point titer determination by fluorescence index.

Science.gov (United States)

Carbone, Teresa; Gilio, Michele; Padula, Maria Carmela; Tramontano, Giuseppina; D'Angelo, Salvatore; Pafundi, Vito

2018-05-01

Indirect Immunofluorescence (IIF) is widely considered the Gold Standard for Antinuclear Antibody (ANA) screening. However, the high inter-reader variability remains the major disadvantage associated with ANA testing and the main reason for the increasing demand of the computer-aided immunofluorescence microscope. Previous studies proposed the quantification of the fluorescence intensity as an alternative for the classical end-point titer evaluation. However, the different distribution of bright/dark light linked to the nature of the self-antigen and its location in the cells result in different mean fluorescence intensities. The aim of the present study was to correlate Fluorescence Index (F.I.) with end-point titers for each well-defined ANA pattern. Routine serum samples were screened for ANA testing on HEp-2000 cells using Immuno Concepts Image Navigator System, and positive samples were serially diluted to assign the end-point titer. A comparison between F.I. and end-point titers related to 10 different staining patterns was made. According to our analysis, good technical performance of F.I. (97% sensitivity and 94% specificity) was found. A significant correlation between quantitative reading of F.I. and end-point titer groups was observed using Spearman's test and regression analysis. A conversion scale of F.I. in end-point titers for each recognized ANA-pattern was obtained. The Image Navigator offers the opportunity to improve worldwide harmonization of ANA test results. In particular, digital F.I. allows quantifying ANA titers by using just one sample dilution. It could represent a valuable support for the routine laboratory and an effective tool to reduce inter- and intra-laboratory variability. Copyright © 2018. Published by Elsevier B.V.

A man in the loop trajectory optimization program (MILTOP)

Science.gov (United States)

Reinfields, J.

1974-01-01

An interactive trajectory optimization program is developed for use in initial fixing of launch configurations. The program is called MILTOP for Man-In-the-Loop-Trajectory Optimization-Program. The program is designed to facilitate quick look studies using man-machine decision combinations to reduce the time required to solve a given problem. MILTOP integrates the equations of motion of a point-mass in 3-Dimensions with drag as the only aerodynamic force present. Any point in time at which an integration step terminates, may be used as a decision-break-point, with complete user control over all variables and routines at this point. Automatic phases are provided for different modes of control: vertical rise, pitch-over, gravity turn, chi-freeze and control turn. Stage parameters are initialized from a separate routine so the user may fly as many stages as his problem demands. The MILTOP system uses both interactively on storage scope consoles, or in batch mode with numerical output on the live printer.

Modeling hard clinical end-point data in economic analyses.

Science.gov (United States)

Kansal, Anuraag R; Zheng, Ying; Palencia, Roberto; Ruffolo, Antonio; Hass, Bastian; Sorensen, Sonja V

2013-11-01

The availability of hard clinical end-point data, such as that on cardiovascular (CV) events among patients with type 2 diabetes mellitus, is increasing, and as a result there is growing interest in using hard end-point data of this type in economic analyses. This study investigated published approaches for modeling hard end-points from clinical trials and evaluated their applicability in health economic models with different disease features. A review of cost-effectiveness models of interventions in clinically significant therapeutic areas (CV diseases, cancer, and chronic lower respiratory diseases) was conducted in PubMed and Embase using a defined search strategy. Only studies integrating hard end-point data from randomized clinical trials were considered. For each study included, clinical input characteristics and modeling approach were summarized and evaluated. A total of 33 articles (23 CV, eight cancer, two respiratory) were accepted for detailed analysis. Decision trees, Markov models, discrete event simulations, and hybrids were used. Event rates were incorporated either as constant rates, time-dependent risks, or risk equations based on patient characteristics. Risks dependent on time and/or patient characteristics were used where major event rates were >1%/year in models with fewer health states (Models of infrequent events or with numerous health states generally preferred constant event rates. The detailed modeling information and terminology varied, sometimes requiring interpretation. Key considerations for cost-effectiveness models incorporating hard end-point data include the frequency and characteristics of the relevant clinical events and how the trial data is reported. When event risk is low, simplification of both the model structure and event rate modeling is recommended. When event risk is common, such as in high risk populations, more detailed modeling approaches, including individual simulations or explicitly time-dependent event rates, are

Comparison of methods for accurate end-point detection of potentiometric titrations

Science.gov (United States)

Villela, R. L. A.; Borges, P. P.; Vyskočil, L.

2015-01-01

Detection of the end point in potentiometric titrations has wide application on experiments that demand very low measurement uncertainties mainly for certifying reference materials. Simulations of experimental coulometric titration data and consequential error analysis of the end-point values were conducted using a programming code. These simulations revealed that the Levenberg-Marquardt method is in general more accurate than the traditional second derivative technique used currently as end-point detection for potentiometric titrations. Performance of the methods will be compared and presented in this paper.

Comparison of methods for accurate end-point detection of potentiometric titrations

International Nuclear Information System (INIS)

Villela, R L A; Borges, P P; Vyskočil, L

2015-01-01

Detection of the end point in potentiometric titrations has wide application on experiments that demand very low measurement uncertainties mainly for certifying reference materials. Simulations of experimental coulometric titration data and consequential error analysis of the end-point values were conducted using a programming code. These simulations revealed that the Levenberg-Marquardt method is in general more accurate than the traditional second derivative technique used currently as end-point detection for potentiometric titrations. Performance of the methods will be compared and presented in this paper

Mean motion and trajectories of heavy particles falling through a boundary layer

Energy Technology Data Exchange (ETDEWEB)

Stout, J.E.; Arya, S.P. [North Carolina State Univ., Raleigh, NC (United States)

1994-12-31

As particles fall through a turbulent boundary layer they experience a rather complex and unique time series of aerodynamic forces and, thus, each individual particle follows a rather complex and unique trajectory to the surface. For sufficiently large and heavy particles, the turbulence induced particle motion can be thought of as a small perturbation superimposed on the mean trajectory. By ignoring the turbulent contribution to particle motion it is possible to calculate the trajectory of a particle due to the mean flow alone. The mean trajectory provides an estimate of the ensemble-averaged path of a set of particles released from a given point in the atmosphere. The effect of turbulence on individual particle trajectories, the distribution of particle displacements from the mean trajectory, and their deposition patterns on the surface will be investigated in a separate study, using a random walk model.

Walking Ahead: The Headed Social Force Model.

Directory of Open Access Journals (Sweden)

Francesco Farina

Full Text Available Human motion models are finding an increasing number of novel applications in many different fields, such as building design, computer graphics and robot motion planning. The Social Force Model is one of the most popular alternatives to describe the motion of pedestrians. By resorting to a physical analogy, individuals are assimilated to point-wise particles subject to social forces which drive their dynamics. Such a model implicitly assumes that humans move isotropically. On the contrary, empirical evidence shows that people do have a preferred direction of motion, walking forward most of the time. Lateral motions are observed only in specific circumstances, such as when navigating in overcrowded environments or avoiding unexpected obstacles. In this paper, the Headed Social Force Model is introduced in order to improve the realism of the trajectories generated by the classical Social Force Model. The key feature of the proposed approach is the inclusion of the pedestrians' heading into the dynamic model used to describe the motion of each individual. The force and torque representing the model inputs are computed as suitable functions of the force terms resulting from the traditional Social Force Model. Moreover, a new force contribution is introduced in order to model the behavior of people walking together as a single group. The proposed model features high versatility, being able to reproduce both the unicycle-like trajectories typical of people moving in open spaces and the point-wise motion patterns occurring in high density scenarios. Extensive numerical simulations show an increased regularity of the resulting trajectories and confirm a general improvement of the model realism.

Quantum Triple Point and Quantum Critical End Points in Metallic Magnets.

Science.gov (United States)

Belitz, D; Kirkpatrick, T R

2017-12-29

In low-temperature metallic magnets, ferromagnetic (FM) and antiferromagnetic (AFM) orders can exist, adjacent to one another or concurrently, in the phase diagram of a single system. We show that universal quantum effects qualitatively alter the known phase diagrams for classical magnets. They shrink the region of concurrent FM and AFM order, change various transitions from second to first order, and, in the presence of a magnetic field, lead to either a quantum triple point where the FM, AFM, and paramagnetic phases all coexist or a quantum critical end point.

Consensus Statement on Diagnostic End Points for Infant Tuberculosis Vaccine Trials

NARCIS (Netherlands)

Hatherill, Mark; Verver, Suzanne; Mahomed, Hassan; Barker, Lew; Behr, Marcel; Cardenas, Vicky; Eisele, Bernd; Douoguih, Macaya; Evans, Thomas G.; Eskola, Juhani; Fourie, Bernard; Grewal, Harleen; Grode, Leander; Hawkridge, Tony; Hesseling, Anneke; Hussey, Gregory; Kiringa, Grace; Landry, Bernard; Lockhart, Stephen; Marais, Ben; Måseide, Kårstein; Mayanja, Harriet; McClain, Bruce; McShane, Helen; Moyo, Sizulu; Ofori, Opokua; Parida, Shreemanta K.; Ryall, Robert P.; Sacarlal, Jahit; Sadoff, Jerry; Shea, Jacqui; Tameris, Michele; van Rie, Annelies; von Reyn, C. Fordham; Wajja, Anne; Walker, Bob; Walzl, Gerhard; Wilkinson, Robert J.

2012-01-01

Background. Definition of clinical trial end points for childhood tuberculosis is hindered by lack of a standard case definition. We aimed to identify areas of consensus or debate on potential end points for tuberculosis vaccine trials among human immunodeficiency virus-uninfected children. Methods.

European network on the determination of site end points for radiologically contaminated land

International Nuclear Information System (INIS)

Booth, Peter; Lennon, Chris

2007-01-01

Nexia Solutions are currently running a small European network entitled 'European Network on the Determination of Site End Points for Radiologically Contaminated Land (ENDSEP)'. Other network members include NRG (Netherlands), UKAEA (UK), CEA (France), SOGIN (Italy), Wismut (Germany), Saxon State Agency of Environment and Geology (Germany). The network is focused on the technical and socio-economical issues associated with the determination of end points for sites potentially, or actually, impacted by radiological contamination. Such issues will cover: - Those associated with the run up to establishing a site end point; - Those associated with verifying that the end points have been met; and Those associated with post closure. The network's current high level objectives can be summarized as follows: Share experience and best practice in the key issues running up to determining site end points; Gain a better understanding of the potential effects of recent and forthcoming EU legislation; Assess consistency between approaches; Highlight potential gaps within the remit of site end point determination and management; and - Consider the formulation of research projects with a view to sharing time and expense. The programme of work revolves around the following key tasks: - Share information, experience and existing good practice. - Look to determine sustainable approaches to contaminated land site end point management. - Through site visits, gain first hand experience of determining an appropriate end point strategy, and identifying and resolving end point issues. Highlight the key data gaps and consider the development of programmes to either close out these gaps or to build confidence in the approaches taken. Production of position papers on each technical are a highlighting how different countries approach/resolve a specific problem. (authors)

Stationkeeping of Lissajous Trajectories in the Earth-Moon System with Applications to ARTEMIS

Science.gov (United States)

Folta, D. C.; Pavlak, T. A.; Howell, K. C.; Woodard, M. A.; Woodfork, D. W.

2010-01-01

In the last few decades, several missions have successfully exploited trajectories near the.Sun-Earth L1 and L2 libration points. Recently, the collinear libration points in the Earth-Moon system have emerged as locations with immediate application. Most libration point orbits, in any system, are inherently unstable. and must be controlled. To this end, several stationkeeping strategies are considered for application to ARTEMIS. Two approaches are examined to investigate the stationkeeping problem in this regime and the specific options. available for ARTEMIS given the mission and vehicle constraints. (I) A baseline orbit-targeting approach controls the vehicle to remain near a nominal trajectory; a related global optimum search method searches all possible maneuver angles to determine an optimal angle and magnitude; and (2) an orbit continuation method, with various formulations determines maneuver locations and minimizes costs. Initial results indicate that consistent stationkeeping costs can be achieved with both approaches and the costs are reasonable. These methods are then applied to Lissajous trajectories representing a baseline ARTEMIS libration orbit trajectory.

Study of Cutting Edge Temperature and Cutting Force of End Mill Tool in High Speed Machining

Directory of Open Access Journals (Sweden)

Kiprawi Mohammad Ashaari

2017-01-01

Full Text Available A wear of cutting tools during machining process is unavoidable due to the presence of frictional forces during removing process of unwanted material of workpiece. It is unavoidable but can be controlled at slower rate if the cutting speed is fixed at certain point in order to achieve optimum cutting conditions. The wear of cutting tools is closely related with the thermal deformations that occurred between the frictional contact point of cutting edge of cutting tool and workpiece. This research paper is focused on determinations of relationship among cutting temperature, cutting speed, cutting forces and radial depth of cutting parameters. The cutting temperature is determined by using the Indium Arsenide (InAs and Indium Antimonide (InSb photocells to measure infrared radiation that are emitted from cutting tools and cutting forces is determined by using dynamometer. The high speed machining process is done by end milling the outer surface of carbon steel. The signal from the photocell is digitally visualized in the digital oscilloscope. Based on the results, the cutting temperature increased as the radial depth and cutting speed increased. The cutting forces increased when radial depth increased but decreased when cutting speed is increased. The setup for calibration and discussion of the experiment will be explained in this paper.

Measurement of β-decay end point energy with planar HPGe detector

Science.gov (United States)

Bhattacharjee, T.; Pandit, Deepak; Das, S. K.; Chowdhury, A.; Das, P.; Banerjee, D.; Saha, A.; Mukhopadhyay, S.; Pal, S.; Banerjee, S. R.

2014-12-01

The β - γ coincidence measurement has been performed with a segmented planar Hyper-Pure Germanium (HPGe) detector and a single coaxial HPGe detector to determine the end point energies of nuclear β-decays. The experimental end point energies have been determined for some of the known β-decays in 106Rh →106Pd. The end point energies corresponding to three weak branches in 106Rh →106Pd decay have been measured for the first time. The γ ray and β particle responses for the planar HPGe detector were simulated using the Monte Carlo based code GEANT3. The experimentally obtained β spectra were successfully reproduced with the simulation.

Non-uniqueness of the point of application of the buoyancy force

International Nuclear Information System (INIS)

Kliava, Janis; Megel, Jacques

2010-01-01

Even though the buoyancy force (also known as the Archimedes force) has always been an important topic of academic studies in physics, its point of application has not been explicitly identified yet. We present a quantitative approach to this problem based on the concept of the hydrostatic energy, considered here for a general shape of the cross-section of a floating body and for an arbitrary angle of heel. We show that the location of the point of application of the buoyancy force essentially depends (i) on the type of motion experienced by the floating body and (ii) on the definition of this point. In a rolling/pitching motion, considerations involving the rotational moment lead to a particular dynamical point of application of the buoyancy force, and for some simple shapes of the floating body this point coincides with the well-known metacentre. On the other hand, from the work-energy relation it follows that in the rolling/pitching motion the energetical point of application of this force is rigidly connected to the centre of buoyancy; in contrast, in a vertical translation this point is rigidly connected to the centre of gravity of the body. Finally, we consider the location of the characteristic points of the floating bodies for some particular shapes of immersed cross-sections. The paper is intended for higher education level physics teachers and students.

Estimated GFR Decline as a Surrogate End Point for Kidney Failure

DEFF Research Database (Denmark)

Lambers Heerspink, Hiddo J; Weldegiorgis, Misghina; Inker, Lesley A

2014-01-01

A doubling of serum creatinine value, corresponding to a 57% decline in estimated glomerular filtration rate (eGFR), is used frequently as a component of a composite kidney end point in clinical trials in type 2 diabetes. The aim of this study was to determine whether alternative end points defin...

End effect braking force reduction in high-speed single-sided linear induction machine

International Nuclear Information System (INIS)

Shiri, Abbas; Shoulaie, Abbas

2012-01-01

Highlights: ► A new analytical equation to model the end effect braking force of SLIM is derived. ► Equations for efficiency, power factor and output thrust are analytically derived. ► The effect of design variables on the performance of the motor is analyzed. ► An optimization method is employed to minimize the end effect braking force (EEBF). ► The results show that EEBF is minimized by appropriate selection of motor parameters. - Abstract: Linear induction motors have been widely employed in industry because of their simple structure and low construction cost. However, they suffer from low efficiency and power factor. In addition, existence of so called end effect influences their performance especially in high speeds. The end effect deteriorates the performance of the motor by producing braking force. So, in this paper, by using Duncan equivalent circuit model, a new analytical equation is proposed to model end effect braking force. Employing the proposed equation and considering all phenomena involved in the single-sided linear induction motor, a simple design procedure is presented and the effect of different design variables on the performance of the motor is analyzed. A multi-objective optimization method based on genetic algorithm is introduced to maximize efficiency and power factor, as well as to minimize the end effect braking force, simultaneously. Finally, to validate the optimization results, 2D finite element method is employed.

Zero-point energy conservation in classical trajectory simulations: Application to H2CO

Science.gov (United States)

Lee, Kin Long Kelvin; Quinn, Mitchell S.; Kolmann, Stephen J.; Kable, Scott H.; Jordan, Meredith J. T.

2018-05-01

A new approach for preventing zero-point energy (ZPE) violation in quasi-classical trajectory (QCT) simulations is presented and applied to H2CO "roaming" reactions. Zero-point energy may be problematic in roaming reactions because they occur at or near bond dissociation thresholds and these channels may be incorrectly open or closed depending on if, or how, ZPE has been treated. Here we run QCT simulations on a "ZPE-corrected" potential energy surface defined as the sum of the molecular potential energy surface (PES) and the global harmonic ZPE surface. Five different harmonic ZPE estimates are examined with four, on average, giving values within 4 kJ/mol—chemical accuracy—for H2CO. The local harmonic ZPE, at arbitrary molecular configurations, is subsequently defined in terms of "projected" Cartesian coordinates and a global ZPE "surface" is constructed using Shepard interpolation. This, combined with a second-order modified Shepard interpolated PES, V, allows us to construct a proof-of-concept ZPE-corrected PES for H2CO, Veff, at no additional computational cost to the PES itself. Both V and Veff are used to model product state distributions from the H + HCO → H2 + CO abstraction reaction, which are shown to reproduce the literature roaming product state distributions. Our ZPE-corrected PES allows all trajectories to be analysed, whereas, in previous simulations, a significant proportion was discarded because of ZPE violation. We find ZPE has little effect on product rotational distributions, validating previous QCT simulations. Running trajectories on V, however, shifts the product kinetic energy release to higher energy than on Veff and classical simulations of kinetic energy release should therefore be viewed with caution.

Transition paths in single-molecule force spectroscopy.

Science.gov (United States)

Cossio, Pilar; Hummer, Gerhard; Szabo, Attila

2018-03-28

In a typical single-molecule force spectroscopy experiment, the ends of the molecule of interest are connected by long polymer linkers to a pair of mesoscopic beads trapped in the focus of two laser beams. At constant force load, the total extension, i.e., the end-to-end distance of the molecule plus linkers, is measured as a function of time. In the simplest systems, the measured extension fluctuates about two values characteristic of folded and unfolded states, with occasional transitions between them. We have recently shown that molecular (un)folding rates can be recovered from such trajectories, with a small linker correction, as long as the characteristic time of the bead fluctuations is shorter than the residence time in the unfolded (folded) state. Here, we show that accurate measurements of the molecular transition path times require an even faster apparatus response. Transition paths, the trajectory segments in which the molecule (un)folds, are properly resolved only if the beads fluctuate more rapidly than the end-to-end distance of the molecule. Therefore, over a wide regime, the measured rates may be meaningful but not the transition path times. Analytic expressions for the measured mean transition path times are obtained for systems diffusing anisotropically on a two-dimensional free energy surface. The transition path times depend on the properties both of the molecule and of the pulling device.

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.

The trajectory of experience of critical care nurses in providing end-of-life care: A qualitative descriptive study.

Science.gov (United States)

Ong, Keh Kiong; Ting, Kit Cheng; Chow, Yeow Leng

2018-01-01

To understand the perceptions of critical care nurses towards providing end-of-life care. There has been an increasing interest in end-of-life care in the critical care setting. In Singapore, approximately half of deaths in the hospital occur during critical care. While nurses are well positioned to provide end-of-life care to patients and their family members, they faced barriers to providing end-of-life care. Also, providing end-of-life care has profound positive and negative psychological effects on nurses, with the latter being more prominent. Qualitative descriptive design. Data collection was performed in a medical intensive care unit of a public tertiary hospital in Singapore. Ten registered nurses were purposively sampled and interviewed individually using a semi-structured interview guide. A codebook was developed to guide coding, and data were thematically analysed. Rigour was maintained. Nurses went through a trajectory of experience. They experienced the culture of care and developed dissatisfaction with it. The tension shaped their perception and meaning of life and death, and they developed mechanisms to reach resolution. This study provides insight on nurses' perception as a trajectory of experience and raised several implications on clinical practice, policy and research. There is a need to alleviate the tension nurses face and to facilitate coming to terms with the tension by improving the culture of care and supporting nurses. Nurses could be involved more in decision-making and empowered to start end-of-life care conversations within the team and with family members. Communication with family members and between nurses and doctors could be improved. Support for nurses providing end-of-life care could be enhanced through promoting social networks, education and bereavement support. Further research is needed to explore ways to support and empower nurses to provide end-of-life care in critical care. © 2017 John Wiley & Sons Ltd.

A Numerical Study of Low-Thrust Limited Power Trajectories between Coplanar Circular Orbits in an Inverse-Square Force Field

Directory of Open Access Journals (Sweden)

Sandro da Silva Fernandes

2012-01-01

Full Text Available A numerical study of optimal low-thrust limited power trajectories for simple transfer (no rendezvous between circular coplanar orbits in an inverse-square force field is performed by two different classes of algorithms in optimization of trajectories. This study is carried out by means of a direct method based on gradient techniques and by an indirect method based on the second variation theory. The direct approach of the trajectory optimization problem combines the main positive characteristics of two well-known direct methods in optimization of trajectories: the steepest-descent (first-order gradient method and a direct second variation (second-order gradient method. On the other hand, the indirect approach of the trajectory optimization problem involves two different algorithms of the well-known neighboring extremals method. Several radius ratios and transfer durations are considered, and the fuel consumption is taken as the performance criterion. For small-amplitude transfers, the results are compared to the ones provided by a linear analytical theory.

Zero-Point Energy Constraint for Unimolecular Dissociation Reactions. Giving Trajectories Multiple Chances To Dissociate Correctly.

Science.gov (United States)

Paul, Amit K; Hase, William L

2016-01-28

A zero-point energy (ZPE) constraint model is proposed for classical trajectory simulations of unimolecular decomposition and applied to CH4* → H + CH3 decomposition. With this model trajectories are not allowed to dissociate unless they have ZPE in the CH3 product. If not, they are returned to the CH4* region of phase space and, if necessary, given additional opportunities to dissociate with ZPE. The lifetime for dissociation of an individual trajectory is the time it takes to dissociate with ZPE in CH3, including multiple possible returns to CH4*. With this ZPE constraint the dissociation of CH4* is exponential in time as expected for intrinsic RRKM dynamics and the resulting rate constant is in good agreement with the harmonic quantum value of RRKM theory. In contrast, a model that discards trajectories without ZPE in the reaction products gives a CH4* → H + CH3 rate constant that agrees with the classical and not quantum RRKM value. The rate constant for the purely classical simulation indicates that anharmonicity may be important and the rate constant from the ZPE constrained classical trajectory simulation may not represent the complete anharmonicity of the RRKM quantum dynamics. The ZPE constraint model proposed here is compared with previous models for restricting ZPE flow in intramolecular dynamics, and connecting product and reactant/product quantum energy levels in chemical dynamics simulations.

Measurement of β-decay end point energy with planar HPGe detector

Energy Technology Data Exchange (ETDEWEB)

Bhattacharjee, T., E-mail: btumpa@vecc.gov.in [Physics Group, Variable Energy Cyclotron Centre, Kolkata 700 064 (India); Pandit, Deepak [Physics Group, Variable Energy Cyclotron Centre, Kolkata 700 064 (India); Das, S.K. [RCD-BARC, Variable Energy Cyclotron Centre, Kolkata 700 064 (India); Chowdhury, A.; Das, P. [Physics Group, Variable Energy Cyclotron Centre, Kolkata 700 064 (India); Banerjee, D. [RCD-BARC, Variable Energy Cyclotron Centre, Kolkata 700 064 (India); Saha, A.; Mukhopadhyay, S.; Pal, S.; Banerjee, S.R. [Physics Group, Variable Energy Cyclotron Centre, Kolkata 700 064 (India)

2014-12-11

The β–γ coincidence measurement has been performed with a segmented planar Hyper-Pure Germanium (HPGe) detector and a single coaxial HPGe detector to determine the end point energies of nuclear β-decays. The experimental end point energies have been determined for some of the known β-decays in {sup 106}Rh→{sup 106}Pd. The end point energies corresponding to three weak branches in {sup 106}Rh→{sup 106}Pd decay have been measured for the first time. The γ ray and β particle responses for the planar HPGe detector were simulated using the Monte Carlo based code GEANT3. The experimentally obtained β spectra were successfully reproduced with the simulation.

Learning-based position control of a closed-kinematic chain robot end-effector

Science.gov (United States)

Nguyen, Charles C.; Zhou, Zhen-Lei

1990-01-01

A trajectory control scheme whose design is based on learning theory, for a six-degree-of-freedom (DOF) robot end-effector built to study robotic assembly of NASA hardwares in space is presented. The control scheme consists of two control systems: the feedback control system and the learning control system. The feedback control system is designed using the concept of linearization about a selected operating point, and the method of pole placement so that the closed-loop linearized system is stabilized. The learning control scheme consisting of PD-type learning controllers, provides additional inputs to improve the end-effector performance after each trial. Experimental studies performed on a 2 DOF end-effector built at CUA, for three tracking cases show that actual trajectories approach desired trajectories as the number of trials increases. The tracking errors are substantially reduced after only five trials.

Guidelines for time-to-event end-point definitions in trials for pancreatic cancer. Results of the DATECAN initiative (Definition for the Assessment of Time-to-event End-points in CANcer trials).

Science.gov (United States)

Bonnetain, Franck; Bonsing, Bert; Conroy, Thierry; Dousseau, Adelaide; Glimelius, Bengt; Haustermans, Karin; Lacaine, François; Van Laethem, Jean Luc; Aparicio, Thomas; Aust, Daniela; Bassi, Claudio; Berger, Virginie; Chamorey, Emmanuel; Chibaudel, Benoist; Dahan, Laeticia; De Gramont, Aimery; Delpero, Jean Robert; Dervenis, Christos; Ducreux, Michel; Gal, Jocelyn; Gerber, Erich; Ghaneh, Paula; Hammel, Pascal; Hendlisz, Alain; Jooste, Valérie; Labianca, Roberto; Latouche, Aurelien; Lutz, Manfred; Macarulla, Teresa; Malka, David; Mauer, Muriel; Mitry, Emmanuel; Neoptolemos, John; Pessaux, Patrick; Sauvanet, Alain; Tabernero, Josep; Taieb, Julien; van Tienhoven, Geertjan; Gourgou-Bourgade, Sophie; Bellera, Carine; Mathoulin-Pélissier, Simone; Collette, Laurence

2014-11-01

Using potential surrogate end-points for overall survival (OS) such as Disease-Free- (DFS) or Progression-Free Survival (PFS) is increasingly common in randomised controlled trials (RCTs). However, end-points are too often imprecisely defined which largely contributes to a lack of homogeneity across trials, hampering comparison between them. The aim of the DATECAN (Definition for the Assessment of Time-to-event End-points in CANcer trials)-Pancreas project is to provide guidelines for standardised definition of time-to-event end-points in RCTs for pancreatic cancer. Time-to-event end-points currently used were identified from a literature review of pancreatic RCT trials (2006-2009). Academic research groups were contacted for participation in order to select clinicians and methodologists to participate in the pilot and scoring groups (>30 experts). A consensus was built after 2 rounds of the modified Delphi formal consensus approach with the Rand scoring methodology (range: 1-9). For pancreatic cancer, 14 time to event end-points and 25 distinct event types applied to two settings (detectable disease and/or no detectable disease) were considered relevant and included in the questionnaire sent to 52 selected experts. Thirty experts answered both scoring rounds. A total of 204 events distributed over the 14 end-points were scored. After the first round, consensus was reached for 25 items; after the second consensus was reached for 156 items; and after the face-to-face meeting for 203 items. The formal consensus approach reached the elaboration of guidelines for standardised definitions of time-to-event end-points allowing cross-comparison of RCTs in pancreatic cancer. Copyright © 2014 Elsevier Ltd. All rights reserved.

The OPALS Plan for Operations: Use of ISS Trajectory and Attitude Models in the OPALS Pointing Strategy

Science.gov (United States)

Abrahamson, Matthew J.; Oaida, Bogdan; Erkmen, Baris

2013-01-01

This paper will discuss the OPALS pointing strategy, focusing on incorporation of ISS trajectory and attitude models to build pointing predictions. Methods to extrapolate an ISS prediction based on past data will be discussed and will be compared to periodically published ISS predictions and Two-Line Element (TLE) predictions. The prediction performance will also be measured against GPS states available in telemetry. The performance of the pointing products will be compared to the allocated values in the OPALS pointing budget to assess compliance with requirements.

Longitudinal forces acting at side-to-end and end-to-side anastomoses when a knitted polyester arterial prosthesis is implanted in the dog.

Science.gov (United States)

Dadgar, L; Downs, A R; Deng, X; Marois, Y; King, M W; Martin, L; Guidoin, R

1995-01-01

In a previous study, which investigated the tensions at the proximal and distal end-to-end anastomoses of a vascular prosthesis, no significant differences were found in the longitudinal forces between the two anastomotic sites after different periods of implantation. The present follow-up study was devised to study the longitudinal forces at a proximal side-to-end and a distal end-to-side anastomosis using a warp knitted polyester prosthesis implanted as a canine thorocoabdominal bypass. The external surface of the prosthesis contained a specially printed "tension indicator" design, which enabled changes in length to be assessed photographically at the two anastomoses at the time of implantation and at sacrifice. The longitudinal force at each site was then calculated using a relationship obtained experimentally between the total longitudinal force and the changes in length of the virgin graft in vitro. The in vitro measurements on the prosthesis were performed using a computer-controlled laser calibration system. Although the results showed a tendency toward a gradual loss in longitudinal force at both anastomoses over 7 months in situ, statistical analysis showed no significant difference in the longitudinal force at the two anastomotic sites after any period of implantation. Histopathological and textile analysis also showed that the characteristics of the prostheses were similar at both anastomotic sites. This does not mean, however, that the intramural stress concentrations experienced by the two sites were the same. While comparing the level of the longitudinal forces measured in this study with those observed in the previous thoracic aorta study using end-to-end anastomoses, no significant differences were observed due to the different types of anastomoses. It would appear that the longitudinal force is not one of the main etiological factors that cause the formation and localization of anastomotic failure.

End points for validating early warning scores in the context of rapid response systems

DEFF Research Database (Denmark)

Pedersen, N. E.; Oestergaard, D.; Lippert, A.

2016-01-01

with optimal treatment. This could pose a limitation to studies using these end points. We studied current expert opinion on end points for validating tools for the identification of patients in hospital wards at risk of imminent critical illness. METHODS: The Delphi consensus methodology was used. We......INTRODUCTION: When investigating early warning scores and similar physiology-based risk stratification tools, death, cardiac arrest and intensive care unit admission are traditionally used as end points. A large proportion of the patients identified by these end points cannot be saved, even...

Non-equilibrium trajectory dynamics and the kinematics of gliding in a flying snake

International Nuclear Information System (INIS)

Socha, John J; Jafari, Farid; Miklasz, Kevin; Vlachos, Pavlos P

2010-01-01

Given sufficient space, it is possible for gliding animals to reach an equilibrium state with no net forces acting on the body. In contrast, every gliding trajectory must begin with a non-steady component, and the relative importance of this phase is not well understood. Of any terrestrial animal glider, snakes exhibit the greatest active movements, which may affect their trajectory dynamics. Our primary aim was to determine the characteristics of snake gliding during the transition to equilibrium, quantifying changes in velocity, acceleration, and body orientation in the late phase of a glide sequence. We launched 'flying' snakes (Chrysopelea paradisi) from a 15 m tower and recorded the mid-to-end portion of trajectories with four videocameras to reconstruct the snake's body position with mm to cm accuracy. Additionally, we developed a simple analytical model of gliding assuming only steady-state forces of lift, drag and weight acting on the body and used it to explore effects of wing loading, lift-to-drag ratio, and initial velocity on trajectory dynamics. Despite the vertical space provided to transition to steady-state gliding, snakes did not exhibit equilibrium gliding and in fact displayed a net positive acceleration in the vertical axis, an effect also predicted by the analytical model.

Non-equilibrium trajectory dynamics and the kinematics of gliding in a flying snake

Energy Technology Data Exchange (ETDEWEB)

Socha, John J; Jafari, Farid [Engineering Science and Mechanics, Virginia Tech, Blacksburg, VA 24061 (United States); Miklasz, Kevin [Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950 (United States); Vlachos, Pavlos P, E-mail: jjsocha@vt.ed [Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA 24061 (United States)

2010-12-15

Given sufficient space, it is possible for gliding animals to reach an equilibrium state with no net forces acting on the body. In contrast, every gliding trajectory must begin with a non-steady component, and the relative importance of this phase is not well understood. Of any terrestrial animal glider, snakes exhibit the greatest active movements, which may affect their trajectory dynamics. Our primary aim was to determine the characteristics of snake gliding during the transition to equilibrium, quantifying changes in velocity, acceleration, and body orientation in the late phase of a glide sequence. We launched 'flying' snakes (Chrysopelea paradisi) from a 15 m tower and recorded the mid-to-end portion of trajectories with four videocameras to reconstruct the snake's body position with mm to cm accuracy. Additionally, we developed a simple analytical model of gliding assuming only steady-state forces of lift, drag and weight acting on the body and used it to explore effects of wing loading, lift-to-drag ratio, and initial velocity on trajectory dynamics. Despite the vertical space provided to transition to steady-state gliding, snakes did not exhibit equilibrium gliding and in fact displayed a net positive acceleration in the vertical axis, an effect also predicted by the analytical model.

A smooth landscape: ending saddle point inflation requires features to be shallow

International Nuclear Information System (INIS)

Battefeld, Diana; Battefeld, Thorsten

2013-01-01

We consider inflation driven near a saddle point in a higher dimensional field space, which is the most likely type of slow roll inflation on the string theoretical landscape; anthropic arguments need to be invoked in order to find a sufficiently flat region. To give all inflatons large masses after inflation and yield a small but positive cosmological constant, the trajectory in field space needs to terminate in a hole on the inflationary plateau, introducing a curved end-of-inflation hypersurface. We compute non-Gaussianities (bi- and tri-spectrum) caused by this curved hyper-surface and find a negative, potentially large, local non-linearity parameter. To be consistent with current observational bounds, the hole needs to be shallow, i.e. considerably wider than deep in natural units. To avoid singling out our vacuum as special (i.e. more special than a positive cosmological constant entails), we deduce that all features on field space should be similarly shallow, severely limiting the type of landscapes one may use for inflationary model building. We justify the use of a truncated Fourier series with random coefficients, which are suppressed the higher the frequency, to model such a smooth landscape by a random potential, as is often done in the literature without a good a priory reason

Four points function fitted and first derivative procedure for determining the end points in potentiometric titration curves: statistical analysis and method comparison.

Science.gov (United States)

Kholeif, S A

2001-06-01

A new method that belongs to the differential category for determining the end points from potentiometric titration curves is presented. It uses a preprocess to find first derivative values by fitting four data points in and around the region of inflection to a non-linear function, and then locate the end point, usually as a maximum or minimum, using an inverse parabolic interpolation procedure that has an analytical solution. The behavior and accuracy of the sigmoid and cumulative non-linear functions used are investigated against three factors. A statistical evaluation of the new method using linear least-squares method validation and multifactor data analysis are covered. The new method is generally applied to symmetrical and unsymmetrical potentiometric titration curves, and the end point is calculated using numerical procedures only. It outperforms the "parent" regular differential method in almost all factors levels and gives accurate results comparable to the true or estimated true end points. Calculated end points from selected experimental titration curves compatible with the equivalence point category of methods, such as Gran or Fortuin, are also compared with the new method.

Implementation and analysis of trajectory schemes for informate: a serial link robot manipulator

International Nuclear Information System (INIS)

Rauf, A.; Ahmed, S.M.; Asif, M.; Ahmad, M.

1997-01-01

Trajectory planning schemes generally interpolate or approximate the desired path by a class of polynomial functions and generate a sequence of time based control set points for the control of the manipulator movement from certain initial configuration to final configuration. Schemes for trajectory generation can be implemented in Joint space and in Cartesian space. This paper describes Joint Space trajectory schemes and Cartesian Space trajectory schemes and their implementation for Infomate, a six degrees of freedom serial link robot manipulator. LSPBs and cubic Spline are chosen as interpolating functions of time for each type of schemes. Modules developed have been incorporated in an OLP system for Infomate. Trajectory planning Schemes discussed in this paper incorporate the constraints of velocities and accelerations of the actuators. comparison with respect to computation and motion time is presented for above mentioned trajectory schemes. Algorithms have been developed that enable the end effector to follow a straight line; other paths like circle, ellipse, etc. can be approximated by straight line segments. (author)

Robot-assisted adaptive training: custom force fields for teaching movement patterns.

Science.gov (United States)

Patton, James L; Mussa-Ivaldi, Ferdinando A

2004-04-01

Based on recent studies of neuro-adaptive control, we tested a new iterative algorithm to generate custom training forces to "trick" subjects into altering their target-directed reaching movements to a prechosen movement as an after-effect of adaptation. The prechosen movement goal, a sinusoidal-shaped path from start to end point, was never explicitly conveyed to the subject. We hypothesized that the adaptation would cause an alteration in the feedforward command that would result in the prechosen movement. Our results showed that when forces were suddenly removed after a training period of 330 movements, trajectories were significantly shifted toward the prechosen movement. However, de-adaptation occurred (i.e., the after-effect "washed out") in the 50-75 movements that followed the removal of the training forces. A second experiment suppressed vision of hand location and found a detectable reduction in the washout of after-effects, suggesting that visual feedback of error critically influences learning. A final experiment demonstrated that after-effects were also present in the neighborhood of training--44% of original directional shift was seen in adjacent, unpracticed movement directions to targets that were 60 degrees different from the targets used for training. These results demonstrate the potential for these methods for teaching motor skills and for neuro-rehabilitation of brain-injured patients. This is a form of "implicit learning," because unlike explicit training methods, subjects learn movements with minimal instructions, no knowledge of, and little attention to the trajectory.

Electronic zero-point fluctuation forces inside circuit components

Science.gov (United States)

Leonhardt, Ulf

2018-01-01

One of the most intriguing manifestations of quantum zero-point fluctuations are the van der Waals and Casimir forces, often associated with vacuum fluctuations of the electromagnetic field. We study generalized fluctuation potentials acting on internal degrees of freedom of components in electrical circuits. These electronic Casimir-like potentials are induced by the zero-point current fluctuations of any general conductive circuit. For realistic examples of an electromechanical capacitor and a superconducting qubit, our results reveal the possibility of tunable forces between the capacitor plates, or the level shifts of the qubit, respectively. Our analysis suggests an alternative route toward the exploration of Casimir-like fluctuation potentials, namely, by characterizing and measuring them as a function of parameters of the environment. These tunable potentials may be useful for future nanoelectromechanical and quantum technologies. PMID:29719863

Electronic zero-point fluctuation forces inside circuit components.

Science.gov (United States)

Shahmoon, Ephraim; Leonhardt, Ulf

2018-04-01

One of the most intriguing manifestations of quantum zero-point fluctuations are the van der Waals and Casimir forces, often associated with vacuum fluctuations of the electromagnetic field. We study generalized fluctuation potentials acting on internal degrees of freedom of components in electrical circuits. These electronic Casimir-like potentials are induced by the zero-point current fluctuations of any general conductive circuit. For realistic examples of an electromechanical capacitor and a superconducting qubit, our results reveal the possibility of tunable forces between the capacitor plates, or the level shifts of the qubit, respectively. Our analysis suggests an alternative route toward the exploration of Casimir-like fluctuation potentials, namely, by characterizing and measuring them as a function of parameters of the environment. These tunable potentials may be useful for future nanoelectromechanical and quantum technologies.

Learning and Correcting Robot Trajectory Keypoints from a Single Demonstration

DEFF Research Database (Denmark)

Juan, Iñigo Iturrate San; Østergaard, Esben Hallundbæk; Rytter, Martin

2017-01-01

of a trajectory from a single demonstration. Additionally, by utilizing velocity information in the task space, the method is able to achieve a level of precision that is sufficient for industrial assembly tasks. Along with this, we present a user study that shows that our method enables non-expert robot users......Kinesthetic teaching provides an accessible way for non-experts to quickly and easily program a robot system by demonstration. A crucial aspect of this technique is to obtain an accurate approximation of the robot’s intended trajectory for the task, while filtering out spurious aspects...... of the demonstration. While several methods to this end have been proposed, they either rely on several demonstrations or on the user explicitly indicating relevant trajectory waypoints. We propose a method, based on the Douglas-Peucker line simplification algorithm that is able to extract the notable points...

A STUDY OF SHUTTLECOCK'S TRAJECTORY IN BADMINTON

Directory of Open Access Journals (Sweden)

Yung-Jen Chen

2009-12-01

Full Text Available The main purpose of this study was to construct and validate a motion equation for the flight of the badminton and to find the relationship between the air resistance force and a shuttlecock's speed. This research method was based on motion laws of aerodynamics. It applied aerodynamic theories to construct motion equation of a shuttlecock's flying trajectory under the effects of gravitational force and air resistance force. The result showed that the motion equation of a shuttlecock's flight trajectory could be constructed by determining the terminal velocity. The predicted shuttlecock trajectory fitted the measured data fairly well. The results also revealed that the drag force was proportional to the square of a shuttlecock velocity. Furthermore, the angle and strength of a stroke could influence trajectory. Finally, this study suggested that we could use a scientific approach to measure a shuttlecock's velocity objectively when testing the quality of shuttlecocks. And could be used to replace the traditional subjective method of the Badminton World Federation based on players' striking shuttlecocks, as well as applying research findings to improve professional knowledge of badminton player training

Guidelines for time-to-event end-point definitions in trials for pancreatic cancer. Results of the DATECAN initiative (Definition for the Assessment of Time-to-event End-points in CANcer trials)

NARCIS (Netherlands)

Bonnetain, Franck; Bonsing, Bert; Conroy, Thierry; Dousseau, Adelaide; Glimelius, Bengt; Haustermans, Karin; Lacaine, François; van Laethem, Jean Luc; Aparicio, Thomas; Aust, Daniela; Bassi, Claudio; Berger, Virginie; Chamorey, Emmanuel; Chibaudel, Benoist; Dahan, Laeticia; de Gramont, Aimery; Delpero, Jean Robert; Dervenis, Christos; Ducreux, Michel; Gal, Jocelyn; Gerber, Erich; Ghaneh, Paula; Hammel, Pascal; Hendlisz, Alain; Jooste, Valérie; Labianca, Roberto; Latouche, Aurelien; Lutz, Manfred; Macarulla, Teresa; Malka, David; Mauer, Muriel; Mitry, Emmanuel; Neoptolemos, John; Pessaux, Patrick; Sauvanet, Alain; Tabernero, Josep; Taieb, Julien; van Tienhoven, Geertjan; Gourgou-Bourgade, Sophie; Bellera, Carine; Mathoulin-Pélissier, Simone; Collette, Laurence

2014-01-01

Using potential surrogate end-points for overall survival (OS) such as Disease-Free- (DFS) or Progression-Free Survival (PFS) is increasingly common in randomised controlled trials (RCTs). However, end-points are too often imprecisely defined which largely contributes to a lack of homogeneity across

EGUN, Charged Particle Trajectories in Electromagnetic Focusing System

International Nuclear Information System (INIS)

Herrmannsfeldt, W.B.

2002-01-01

1 - Description of problem or function: EGUN computes trajectories of charged particles in electrostatic and magnetostatic focusing systems including the effects of space charge and self-magnetic fields. Starting options include Child's Law conditions on cathodes of various shapes, user-specified conditions input for each ray, and a combination of Child's Law conditions and user specifications. Either rectangular or cylindrically symmetric geometry may be used. Magnetic fields may be specified using an arbitrary configuration of coils, or the output of a magnet program, such as Poisson, or by an externally calculated array of the axial fields. 2 - Method of solution: The program first solves Laplace's equation. Next, the first iteration of electron trajectories is started using one of the four starting options. On the first iteration cycle, space charge forces are calculated from the assumption of paraxial flow. As the rays are traced, space charge is computed and stored. After all the electron trajectories have been calculated, the program begins the second cycle by solving the Poisson equation with the space charge from the first iteration. Subsequent iteration cycles follow this pattern. The Poisson equation is solved by an alternate column relaxation technique known as the semi-iterative Chebyshev method. A fourth-order Runge-Kutta method is used to solve the relativistic differential equations of the trajectory calculations. 3 - Restrictions on the complexity of the problem - Maxima of: 9001 mesh points in a square mesh, 300 mesh points in the axial direction, 100 mesh points in the radial direction, 101 potentials, 51 rays. In the cylindrical coordinates, the magnetic fields are axially symmetric. In rectangular coordinates, the external field is assumed to be normal to the plane of the problem, which is assumed to be the median plane

Navigating role forces and the aesthetic|authentic caring dialectic: a novice urban science teacher's developmental trajectory

Science.gov (United States)

Rivera Maulucci, Maria S.

2010-09-01

Examining role forces and resources available to new teachers is crucial to understanding how teachers use and expand cultural, social, and symbolic resources and how they engage teaching for social justice and caring in urban science education. This critical narrative inquiry explores three levels of story. First, the narratives explore my role as a district science staff developer and my efforts to leverage district resources to improve students' opportunities to learn science. Second, the narratives explore the ways in which a novice science teacher, Tina, navigated role forces and the aesthetic|authentic caring dialectic in a high poverty, urban school. A third level of narrative draws on sociological theories of human interaction to explore role forces and how they shaped Tina's developmental trajectory. I describe how Tina expanded cultural, social, and symbolic resources to enact her teaching role.

End point control of an actinide precipitation reactor

International Nuclear Information System (INIS)

Muske, K.R.

1997-01-01

The actinide precipitation reactors in the nuclear materials processing facility at Los Alamos National Laboratory are used to remove actinides and other heavy metals from the effluent streams generated during the purification of plutonium. These effluent streams consist of hydrochloric acid solutions, ranging from one to five molar in concentration, in which actinides and other metals are dissolved. The actinides present are plutonium and americium. Typical actinide loadings range from one to five grams per liter. The most prevalent heavy metals are iron, chromium, and nickel that are due to stainless steel. Removal of these metals from solution is accomplished by hydroxide precipitation during the neutralization of the effluent. An end point control algorithm for the semi-batch actinide precipitation reactors at Los Alamos National Laboratory is described. The algorithm is based on an equilibrium solubility model of the chemical species in solution. This model is used to predict the amount of base hydroxide necessary to reach the end point of the actinide precipitation reaction. The model parameters are updated by on-line pH measurements

Distributions of chain ends and junction points in ordered block copolymers

International Nuclear Information System (INIS)

Mayes, A.M.; Johnson, R.D.; Russell, T.P.; Smith, S.D.; Satija, S.K.; Majkrzak, C.F.

1993-01-01

Chain configurations in ordered symmetric poly(styrene-b-methyl methacrylate) diblock copolymers were examined by neutron reflectively. In a thin-film geometry the copolymers organize into lamellar microdomains oriented parallel to the substrate surface. The copolymers organize into lamellar microdomains oriented parallel to the substrate surface. The copolymers were synthesized with small fractions of deuterated segments at either the chain ends or centers. This selective labeling permitted characterization of the spatial distribution of chain ends and junction points normal to the plane of the film. From the reflectivity analysis, the junction points are found to be confined to the PS/PMMA interfacial regions. The chain ends, however, are well distributed through their respective domains, exhibiting only a weak maximum in concentration at the center of the domains

Stabilization at almost arbitrary points for chaotic systems

International Nuclear Information System (INIS)

Huang, C.-S.; Lian, K.-Y.; Su, C.-H.; Wu, J.-W.

2008-01-01

We consider how to design a feasible control input for chaotic systems via a suitable input channel to achieve the stabilization at arbitrary points. Regarding the nonlinear systems without naturally defined input vectors, we propose a local stabilization controller which works for almost arbitrary points. Subsequently, according to topologically transitive property for chaotic systems, the feedback control force is activated only when the trajectory passes through the neighboring region of the regulated point. Hence the global stabilization is achieved whereas the control effort of the hybrid controller is extremely low

Application of fixed point theory to chaotic attractors of forced oscillators

International Nuclear Information System (INIS)

Stewart, H.B.

1990-11-01

A review of the structure of chaotic attractors of periodically forced second order nonlinear oscillators suggests that the theory of fixed points of transformations gives information about the fundamental topological structure of attractors. First a simple extension of the Levinson index formula is proved. Then numerical evidence is used to formulate plausible conjectures about absorbing regions containing chaotic attractors in forced oscillators. Applying the Levinson formula suggests a fundamental relation between the number of fixed points or periodic points in a section of the chaotic attractor on the one hand, and a topological invariant of an absorbing region on the other hand. (author)

Picking Robot Arm Trajectory Planning Method

Directory of Open Access Journals (Sweden)

Zhang Zhiyong

2014-01-01

Full Text Available The picking robot arm is scheduled to complete picking tasks in the working space, to overcome the shaking vibration to improve the picking stability, its movement should follow specific consistence trajectory points. Usually we should give definite multiple feature picking points, map their inverse kinematics to the joint space, establish motion equation for the corresponding point in the joint space, then follow these equations motion for the interpolation on the joint so that we can meet the movement requirements. Trajectory planning is decisive significance for accuracy and stability of controlling robot arm. The key issue that picking arm complete picking task will be come true by trajectory planning, namely, robot arm track the desired trajectory. which based on kinematics and statics picking analysis in a joint space according to the requirements of picking tasks, and obtain the position and orientation for picking robot arm, study and calculate the theory of trajectory parameters timely.

A new exact solution to the classical equations of motion of the relativistic string with massive ends

International Nuclear Information System (INIS)

Barbashov, B.M.; Chervyakov, A.M.

1991-01-01

The classical histories of the relativistic string with massive ends in space-time are examined in terms of geometric invariants of both the string world surface and world lines of the point masses at the string ends. In this formulation the string variables are completely defined by means of the constant curvatures and torsions of the endpoint trajectories which are subjected to a system of differential equations with a delayed arguments that incorporates retardation effects of the interaction of two point masses through the string. The well-known example of the rotating straight-line string with massive ends corresponds to a particular solution of this system for the constant torsions. A new exact solution for the periodic torsions of the world trajectories of the massive string ends is found. In this case the string coordinates are represented in terms of normal elliptic integrals and describe a more intricate motion including its transverse vibrations than rotation of a stretched string in a given plane. 17 refs

Trajectories of martian habitability.

Science.gov (United States)

Cockell, Charles S

2014-02-01

Beginning from two plausible starting points-an uninhabited or inhabited Mars-this paper discusses the possible trajectories of martian habitability over time. On an uninhabited Mars, the trajectories follow paths determined by the abundance of uninhabitable environments and uninhabited habitats. On an inhabited Mars, the addition of a third environment type, inhabited habitats, results in other trajectories, including ones where the planet remains inhabited today or others where planetary-scale life extinction occurs. By identifying different trajectories of habitability, corresponding hypotheses can be described that allow for the various trajectories to be disentangled and ultimately a determination of which trajectory Mars has taken and the changing relative abundance of its constituent environments.

The probability of false positives in zero-dimensional analyses of one-dimensional kinematic, force and EMG trajectories.

Science.gov (United States)

Pataky, Todd C; Vanrenterghem, Jos; Robinson, Mark A

2016-06-14

A false positive is the mistake of inferring an effect when none exists, and although α controls the false positive (Type I error) rate in classical hypothesis testing, a given α value is accurate only if the underlying model of randomness appropriately reflects experimentally observed variance. Hypotheses pertaining to one-dimensional (1D) (e.g. time-varying) biomechanical trajectories are most often tested using a traditional zero-dimensional (0D) Gaussian model of randomness, but variance in these datasets is clearly 1D. The purpose of this study was to determine the likelihood that analyzing smooth 1D data with a 0D model of variance will produce false positives. We first used random field theory (RFT) to predict the probability of false positives in 0D analyses. We then validated RFT predictions via numerical simulations of smooth Gaussian 1D trajectories. Results showed that, across a range of public kinematic, force/moment and EMG datasets, the median false positive rate was 0.382 and not the assumed α=0.05, even for a simple two-sample t test involving N=10 trajectories per group. The median false positive rate for experiments involving three-component vector trajectories was p=0.764. This rate increased to p=0.945 for two three-component vector trajectories, and to p=0.999 for six three-component vectors. This implies that experiments involving vector trajectories have a high probability of yielding 0D statistical significance when there is, in fact, no 1D effect. Either (a) explicit a priori identification of 0D variables or (b) adoption of 1D methods can more tightly control α. Copyright © 2016 Elsevier Ltd. All rights reserved.

What Is the End of Life Period? Trajectories and Characterization Based on Primary Caregiver Reports.

Science.gov (United States)

Cohen-Mansfield, Jiska; Cohen, Rinat; Skornick-Bouchbinder, Michal; Brill, Shai

2018-04-17

As the population lives longer, end of life (EOL) is emerging as a distinct life phase, about which there is still limited understanding. Characterizing this important period is vital for clarifying issues regarding trajectory and decline at EOL and for health service planning on an institutional, communal, and societal level. In this article, we aim to characterize the EOL period, examining the duration and number of EOL stages, as well as functional, attitudinal, and emotional trajectories. In this cross-sectional study, 70 primary caregivers of deceased persons were interviewed. Standardized rates of functional, attitudinal, and emotional change across the EOL period were calculated. Frequencies were compared using the McNemar statistical test. EOL period was found to have a median length of 3.25 years, and an average of approximately three progressive stages. The duration of EOL stages tended to decrease as death approached. Unexpected events (eg new medical diagnosis/accident) served as the precipitating event for the EOL period for approximately half of the deceased persons, and changes in existing conditions (eg health status/cognitive state) were also reported to precipitate EOL for a similar proportion. Reports of functionality across stages found the steepest decline in the "physical" domain and the most moderate decline in the "social" domain. With each stage, positive indicators, such as "will to live," showed a progressive decline, whereas negative indicators, including "suffering" and "dependence level," progressively increased. Results help characterize EOL trajectories and should inform care planning and decision making at various levels. In addition, they suggest a methodology for better understanding EOL.

A path planning method for robot end effector motion using the curvature theory of the ruled surfaces

Science.gov (United States)

Güler, Fatma; Kasap, Emin

Using the curvature theory for the ruled surfaces a technique for robot trajectory planning is presented. This technique ensures the calculation of robot’s next path. The positional variation of the Tool Center Point (TCP), linear velocity, angular velocity are required in the work area of the robot. In some circumstances, it may not be physically achievable and a re-computation of the robot trajectory might be necessary. This technique is suitable for re-computation of the robot trajectory. We obtain different robot trajectories which change depending on the darboux angle function and define trajectory ruled surface family with a common trajectory curve with the rotation trihedron. Also, the motion of robot end effector is illustrated with examples.

Medication overuse headache: a critical review of end points in recent follow-up studies

DEFF Research Database (Denmark)

Hagen, Knut; Jensen, Rigmor; Bøe, Magne Geir

2010-01-01

in headache index at the end of follow-up were reported in only one and two of nine studies, respectively. The present review demonstrated a lack of uniform end points used in recently published follow-up studies. Guidelines for presenting follow-up data on MOH are needed and we propose end points......No guidelines for performing and presenting the results of studies on patients with medication overuse headache (MOH) exist. The aim of this study was to review long-term outcome measures in follow-up studies published in 2006 or later. We included MOH studies with >6 months duration presenting...... a minimum of one predefined end point. In total, nine studies were identified. The 1,589 MOH patients (22% men) had an overall mean frequency of 25.3 headache days/month at baseline. Headache days/month at the end of follow-up was reported in six studies (mean 13.8 days/month). The decrease was more...

Criteria for use of composite end points for competing risks-a systematic survey of the literature with recommendations.

Science.gov (United States)

Manja, Veena; AlBashir, Siwar; Guyatt, Gordon

2017-02-01

Composite end points are frequently used in reports of clinical trials. One rationale for the use of composite end points is to account for competing risks. In the presence of competing risks, the event rate of a specific event depends on the rates of other competing events. One proposed solution is to include all important competing events in one composite end point. Clinical trialists require guidance regarding when this approach is appropriate. To identify publications describing criteria for use of composite end points for competing risk and to offer guidance regarding when a composite end point is appropriate on the basis of competing risks. We searched MEDLINE, CINAHL, EMBASE, The Cochrane's Central & Systematic Review databases including the Health Technology Assessment database, and the Cochrane's Methodology register from inception to April 2015, and candidate textbooks, to identify all articles providing guidance on this issue. Eligible publications explicitly addressed the issue of a composite outcome to address competing risks. Two reviewers independently screened the titles and abstracts for full-text review; independently reviewed full-text publications; and abstracted specific criteria authors offered for use of composite end points to address competing risks. Of 63,645 titles and abstracts, 166 proved potentially relevant of which 43 publications were included in the final review. Most publications note competing risks as a reason for using composite end points without further elaboration. None of the articles or textbook chapters provide specific criteria for use of composite end points for competing risk. Some advocate using composite end points to avoid bias due to competing risks and others suggest that composite end points seldom or never be used for this purpose. We recommend using composite end points for competing risks only if the competing risk is plausible and if it occurs with sufficiently high frequency to influence the interpretation

Radiometric titration of officinal radiopharmaceuticals using radioactive kryptonates as end-point indicators. II

International Nuclear Information System (INIS)

Harangozo, M.; Jombik, J.; Schiller, P.; Toelgyessy, J.

1981-01-01

A method for the determination of citric, tartaric and undecylenic acids based on radiometric titration with 0.1 or 0.05 mole.l -1 NaOH was developed. As an indicator of the end point, radioactive kryptonate of glass was used. Experimental technique, results of determinations as well as other possible applications of the radioactive kryptonate of glass for end point determination in alkalimetric analyses of officinal pharmaceuticals are discussed. (author)

Development of Constraint Force Equation Methodology for Application to Multi-Body Dynamics Including Launch Vehicle Stage Seperation

Science.gov (United States)

Pamadi, Bandu N.; Toniolo, Matthew D.; Tartabini, Paul V.; Roithmayr, Carlos M.; Albertson, Cindy W.; Karlgaard, Christopher D.

2016-01-01

The objective of this report is to develop and implement a physics based method for analysis and simulation of multi-body dynamics including launch vehicle stage separation. The constraint force equation (CFE) methodology discussed in this report provides such a framework for modeling constraint forces and moments acting at joints when the vehicles are still connected. Several stand-alone test cases involving various types of joints were developed to validate the CFE methodology. The results were compared with ADAMS(Registered Trademark) and Autolev, two different industry standard benchmark codes for multi-body dynamic analysis and simulations. However, these two codes are not designed for aerospace flight trajectory simulations. After this validation exercise, the CFE algorithm was implemented in Program to Optimize Simulated Trajectories II (POST2) to provide a capability to simulate end-to-end trajectories of launch vehicles including stage separation. The POST2/CFE methodology was applied to the STS-1 Space Shuttle solid rocket booster (SRB) separation and Hyper-X Research Vehicle (HXRV) separation from the Pegasus booster as a further test and validation for its application to launch vehicle stage separation problems. Finally, to demonstrate end-to-end simulation capability, POST2/CFE was applied to the ascent, orbit insertion, and booster return of a reusable two-stage-to-orbit (TSTO) vehicle concept. With these validation exercises, POST2/CFE software can be used for performing conceptual level end-to-end simulations, including launch vehicle stage separation, for problems similar to those discussed in this report.

Combined fishing and climate forcing in the southern Benguela upwelling ecosystem: an end-to-end modelling approach reveals dampened effects.

Directory of Open Access Journals (Sweden)

Morgane Travers-Trolet

Full Text Available The effects of climate and fishing on marine ecosystems have usually been studied separately, but their interactions make ecosystem dynamics difficult to understand and predict. Of particular interest to management, the potential synergism or antagonism between fishing pressure and climate forcing is analysed in this paper, using an end-to-end ecosystem model of the southern Benguela ecosystem, built from coupling hydrodynamic, biogeochemical and multispecies fish models (ROMS-N2P2Z2D2-OSMOSE. Scenarios of different intensities of upwelling-favourable wind stress combined with scenarios of fishing top-predator fish were tested. Analyses of isolated drivers show that the bottom-up effect of the climate forcing propagates up the food chain whereas the top-down effect of fishing cascades down to zooplankton in unfavourable environmental conditions but dampens before it reaches phytoplankton. When considering both climate and fishing drivers together, it appears that top-down control dominates the link between top-predator fish and forage fish, whereas interactions between the lower trophic levels are dominated by bottom-up control. The forage fish functional group appears to be a central component of this ecosystem, being the meeting point of two opposite trophic controls. The set of combined scenarios shows that fishing pressure and upwelling-favourable wind stress have mostly dampened effects on fish populations, compared to predictions from the separate effects of the stressors. Dampened effects result in biomass accumulation at the top predator fish level but a depletion of biomass at the forage fish level. This should draw our attention to the evolution of this functional group, which appears as both structurally important in the trophic functioning of the ecosystem, and very sensitive to climate and fishing pressures. In particular, diagnoses considering fishing pressure only might be more optimistic than those that consider combined effects

Automatic entry point planning for robotic post-mortem CT-based needle placement.

Science.gov (United States)

Ebert, Lars C; Fürst, Martin; Ptacek, Wolfgang; Ruder, Thomas D; Gascho, Dominic; Schweitzer, Wolf; Thali, Michael J; Flach, Patricia M

2016-09-01

Post-mortem computed tomography guided placement of co-axial introducer needles allows for the extraction of tissue and liquid samples for histological and toxicological analyses. Automation of this process can increase the accuracy and speed of the needle placement, thereby making it more feasible for routine examinations. To speed up the planning process and increase safety, we developed an algorithm that calculates an optimal entry point and end-effector orientation for a given target point, while taking constraints such as accessibility or bone collisions into account. The algorithm identifies the best entry point for needle trajectories in three steps. First, the source CT data is prepared and bone as well as surface data are extracted and optimized. All vertices of the generated surface polygon are considered to be potential entry points. Second, all surface points are tested for validity within the defined hard constraints (reachability, bone collision as well as collision with other needles) and removed if invalid. All remaining vertices are reachable entry points and are rated with respect to needle insertion angle. Third, the vertex with the highest rating is selected as the final entry point, and the best end-effector rotation is calculated to avoid collisions with the body and already set needles. In most cases, the algorithm is sufficiently fast with approximately 5-6 s per entry point. This is the case if there is no collision between the end-effector and the body. If the end-effector has to be rotated to avoid collision, calculation times can increase up to 24 s due to the inefficient collision detection used here. In conclusion, the algorithm allows for fast and facilitated trajectory planning in forensic imaging.

An algorithm to locate optimal bond breaking points on a potential energy surface for applications in mechanochemistry and catalysis.

Science.gov (United States)

Bofill, Josep Maria; Ribas-Ariño, Jordi; García, Sergio Pablo; Quapp, Wolfgang

2017-10-21

The reaction path of a mechanically induced chemical transformation changes under stress. It is well established that the force-induced structural changes of minima and saddle points, i.e., the movement of the stationary points on the original or stress-free potential energy surface, can be described by a Newton Trajectory (NT). Given a reactive molecular system, a well-fitted pulling direction, and a sufficiently large value of the force, the minimum configuration of the reactant and the saddle point configuration of a transition state collapse at a point on the corresponding NT trajectory. This point is called barrier breakdown point or bond breaking point (BBP). The Hessian matrix at the BBP has a zero eigenvector which coincides with the gradient. It indicates which force (both in magnitude and direction) should be applied to the system to induce the reaction in a barrierless process. Within the manifold of BBPs, there exist optimal BBPs which indicate what is the optimal pulling direction and what is the minimal magnitude of the force to be applied for a given mechanochemical transformation. Since these special points are very important in the context of mechanochemistry and catalysis, it is crucial to develop efficient algorithms for their location. Here, we propose a Gauss-Newton algorithm that is based on the minimization of a positively defined function (the so-called σ-function). The behavior and efficiency of the new algorithm are shown for 2D test functions and for a real chemical example.

Students' Understanding of Boiling Points and Intermolecular Forces

Science.gov (United States)

Schmidt, Hans-Jurgen; Kaufmann, Birgit; Treagust, David F.

2009-01-01

In introductory chemistry courses students are presented with the model that matter is composed of particles, and that weak forces of attraction exist between them. This model is used to interpret phenomena such as solubility and melting points, and aids in understanding the changes in states of matter as opposed to chemical reactions. We…

Electrical breakthrough effect for end pointing in 90 and 45 nm node circuit edit

International Nuclear Information System (INIS)

Liu, Kun; Soskov, Alex; Scipioni, Larry; Bassom, Neil; Sijbrandij, Sybren; Smith, Gerald

2006-01-01

The interaction between high-energy Ga + ions and condensed matter is studied for circuit edit applications. A new 'electrical breakthrough effect' due to charging of, and Ga + penetration/doping into, dielectrics is discovered. This new effect is proposed for end pointing in 90 and 45 nm node circuit edits where integrated circuit device dimensions are of a few hundred nanometers. This new end point approach is very sensitive, reliable, and precise. Most importantly, it is not sensitive to device dimensions. A series of circuit edits involving milling holes of high aspect ratio (5-30) and small cross-section area (0.01-0.25 μm 2 ) on real chips has been successfully performed using the electrical breakthrough effect as the end point method

The growth speed of microtubules with XMAP215-coated beads coupled to their ends is increased by tensile force

Science.gov (United States)

Trushko, Anastasiya; Schäffer, Erik; Howard, Jonathon

2013-01-01

The generation of pulling and pushing forces is one of the important functions of microtubules, which are dynamic and polarized structures. The ends of dynamic microtubules are able to form relatively stable links to cellular structures, so that when a microtubule grows it can exert a pushing force and when it shrinks it can exert a pulling force. Microtubule growth and shrinkage are tightly regulated by microtubule-associated proteins (MAPs) that bind to microtubule ends. Given their localization, MAPs may be exposed to compressive and tensile forces. The effect of such forces on MAP function, however, is poorly understood. Here we show that beads coated with the microtubule polymerizing protein XMAP215, the Xenopus homolog of Dis1 and chTOG, are able to link stably to the plus ends of microtubules, even when the ends are growing or shrinking; at growing ends, the beads increase the polymerization rate. Using optical tweezers, we found that tensile force further increased the microtubule polymerization rate. These results show that physical forces can regulate the activity of MAPs. Furthermore, our results show that XMAP215 can be used as a handle to sense and mechanically manipulate the dynamics of the microtubule tip. PMID:23964126

Trajectory dynamics study of the Ar + CH4 dissociation reaction at high temperatures: the importance of zero-point-energy effects.

Science.gov (United States)

Marques, J M C; Martínez-Núñez, E; Fernandez-Ramos, A; Vazquez, S A

2005-06-23

Large-scale classical trajectory calculations have been performed to study the reaction Ar + CH4--> CH3 +H + Ar in the temperature range 2500 energy surface used for ArCH4 is the sum of the nonbonding pairwise potentials of Hase and collaborators (J. Chem. Phys. 2001, 114, 535) that models the intermolecular interaction and the CH4 intramolecular potential of Duchovic et al. (J. Phys. Chem. 1984, 88, 1339), which has been modified to account for the H-H repulsion at small bending angles. The thermal rate coefficient has been calculated, and the zero-point energy (ZPE) of the CH3 product molecule has been taken into account in the analysis of the results; also, two approaches have been applied for discarding predissociative trajectories. In both cases, good agreement is observed between the experimental and trajectory results after imposing the ZPE of CH3. The energy-transfer parameters have also been obtained from trajectory calculations and compared with available values estimated from experiment using the master equation formalism; in general, the agreement is good.

PANTHER. Trajectory Analysis

Energy Technology Data Exchange (ETDEWEB)

Rintoul, Mark Daniel [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Wilson, Andrew T. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Valicka, Christopher G. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Kegelmeyer, W. Philip [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Shead, Timothy M. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Newton, Benjamin D. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Czuchlewski, Kristina Rodriguez [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

2015-09-01

We want to organize a body of trajectories in order to identify, search for, classify and predict behavior among objects such as aircraft and ships. Existing compari- son functions such as the Fr'echet distance are computationally expensive and yield counterintuitive results in some cases. We propose an approach using feature vectors whose components represent succinctly the salient information in trajectories. These features incorporate basic information such as total distance traveled and distance be- tween start/stop points as well as geometric features related to the properties of the convex hull, trajectory curvature and general distance geometry. Additionally, these features can generally be mapped easily to behaviors of interest to humans that are searching large databases. Most of these geometric features are invariant under rigid transformation. We demonstrate the use of different subsets of these features to iden- tify trajectories similar to an exemplar, cluster a database of several hundred thousand trajectories, predict destination and apply unsupervised machine learning algorithms.

Detection of Bordetella pertussis from Clinical Samples by Culture and End-Point PCR in Malaysian Patients.

Science.gov (United States)

Ting, Tan Xue; Hashim, Rohaidah; Ahmad, Norazah; Abdullah, Khairul Hafizi

2013-01-01

Pertussis or whooping cough is a highly infectious respiratory disease caused by Bordetella pertussis. In vaccinating countries, infants, adolescents, and adults are relevant patients groups. A total of 707 clinical specimens were received from major hospitals in Malaysia in year 2011. These specimens were cultured on Regan-Lowe charcoal agar and subjected to end-point PCR, which amplified the repetitive insertion sequence IS481 and pertussis toxin promoter gene. Out of these specimens, 275 were positive: 4 by culture only, 6 by both end-point PCR and culture, and 265 by end-point PCR only. The majority of the positive cases were from ≤3 months old patients (77.1%) (P 0.05). Our study showed that the end-point PCR technique was able to pick up more positive cases compared to culture method.

A quantitative analysis of statistical power identifies obesity end points for improved in vivo preclinical study design.

Science.gov (United States)

Selimkhanov, J; Thompson, W C; Guo, J; Hall, K D; Musante, C J

2017-08-01

The design of well-powered in vivo preclinical studies is a key element in building the knowledge of disease physiology for the purpose of identifying and effectively testing potential antiobesity drug targets. However, as a result of the complexity of the obese phenotype, there is limited understanding of the variability within and between study animals of macroscopic end points such as food intake and body composition. This, combined with limitations inherent in the measurement of certain end points, presents challenges to study design that can have significant consequences for an antiobesity program. Here, we analyze a large, longitudinal study of mouse food intake and body composition during diet perturbation to quantify the variability and interaction of the key metabolic end points. To demonstrate how conclusions can change as a function of study size, we show that a simulated preclinical study properly powered for one end point may lead to false conclusions based on secondary end points. We then propose the guidelines for end point selection and study size estimation under different conditions to facilitate proper power calculation for a more successful in vivo study design.

PENGENALAN POLA SIDIK JARI RIDGE ENDING DAN BIFURCATION POINT DENGAN EKSTRAKSI MINUSI METODE CROSSING NUMBER

Directory of Open Access Journals (Sweden)

I Putu Dody Lesmana

2012-09-01

Full Text Available Abstract: Biometric is a development of basic method of identification using human natural characteristics as its basic. One of the biometric system that is often used is fingerprint. Fingerprint matching system can be obtained by extraction of minutiae information. Information from minutiae extraction generated ridge ending and bifurcation. The technique coffered in this paper is based on the extraction of minutiae from fingerprint image using crossing number (CN method to get ridge ending and bifurcation point by scanning each of ridges point. False identification of minutiae structure may be introduced into the fingerprint image due to hole and spur structure. It is necessary to test the validity of each minutiae point to eliminate false minutiae. Experiments are firstly conducted to assess how well the crossing number method is able to extract the minutiae point. The minutiae validation algorithm is then evaluated to see how effective the algorithm is in detecting the false minutiae. From experiments result using crossing number method, it can be deduced that all ridge points corresponding to ridge ending and bifurcation point have been detected successfully. However, there are a few cases where the extracted minutiae do not correspond to true minutiae points due to hole and spur structure. Applying minutiae validation algorithm is able to cancel out the false ridge endings created by the spur structure and bifurcations created by the hole structures.

Origin of chaos in 3-d Bohmian trajectories

International Nuclear Information System (INIS)

Tzemos, Athanasios C.; Contopoulos, George; Efthymiopoulos, Christos

2016-01-01

We study the 3-d Bohmian trajectories of a quantum system of three harmonic oscillators. We focus on the mechanism responsible for the generation of chaotic trajectories. We demonstrate the existence of a 3-d analogue of the mechanism found in earlier studies of 2-d systems [1,2], based on moving 2-d ‘nodal point–X-point complexes’. In the 3-d case, we observe a foliation of nodal point–X-point complexes, forming a ‘3-d structure of nodal and X-points’. Chaos is generated when the Bohmian trajectories are scattered at one or more close encounters with such a structure. - Highlights: • A mechanism for the emergence of 3-d Bohmian chaos is proposed. • We demonstrate the existence of a 3-d structure of nodal and X-points. • Chaos is generated when the trajectories are scattered by the X-points.

Origin of chaos in 3-d Bohmian trajectories

Energy Technology Data Exchange (ETDEWEB)

Tzemos, Athanasios C., E-mail: thanasistzemos@gmail.com; Contopoulos, George, E-mail: gcontop@academyofathens.gr; Efthymiopoulos, Christos, E-mail: cefthim@academyofathens.gr

2016-11-25

We study the 3-d Bohmian trajectories of a quantum system of three harmonic oscillators. We focus on the mechanism responsible for the generation of chaotic trajectories. We demonstrate the existence of a 3-d analogue of the mechanism found in earlier studies of 2-d systems [1,2], based on moving 2-d ‘nodal point–X-point complexes’. In the 3-d case, we observe a foliation of nodal point–X-point complexes, forming a ‘3-d structure of nodal and X-points’. Chaos is generated when the Bohmian trajectories are scattered at one or more close encounters with such a structure. - Highlights: • A mechanism for the emergence of 3-d Bohmian chaos is proposed. • We demonstrate the existence of a 3-d structure of nodal and X-points. • Chaos is generated when the trajectories are scattered by the X-points.

A global limit load solution for plates with surface cracks under combined end force and cross-thickness bending

International Nuclear Information System (INIS)

Lei Yuebao; Fox, Mike J.H.

2011-01-01

A global limit load solution for rectangular surface cracks in plates under combined end force and cross-thickness bending is derived, which allows any combination of positive/negative end force and positive/negative cross-thickness moment. The solution is based on the net-section plastic collapse concept and, therefore, gives limit load values based on the Tresca yielding criterion. Solutions for both cases with and without crack face contact are derived when whole or part of the crack is located in the compressive stress zone. From the solution, particular global limit load solutions for plates with extended surface cracks and through-thickness cracks under the same loading conditions are obtained. The solution is consistent with the limit load solution for surface cracks in plates under combined tension and positive bending due to Goodall and Webster and Lei when both the applied end force and bending moment are positive. The solution reduces to the limit load solution for plain plates under combined end force and cross-thickness bending when the crack vanishes. - Highlights: → A global limit load solution for plates with surface cracks in plates is derived. → Combined positive/negative end force and positive/negative cross-thickness moment are considered. → The solution is based on the net-section plastic collapse concept.

Non-Uniqueness of the Point of Application of the Buoyancy Force

Science.gov (United States)

Kliava, Janis; Megel, Jacques

2010-01-01

Even though the buoyancy force (also known as the Archimedes force) has always been an important topic of academic studies in physics, its point of application has not been explicitly identified yet. We present a quantitative approach to this problem based on the concept of the hydrostatic energy, considered here for a general shape of the…

Free-time and fixed end-point multi-target optimal control theory: Application to quantum computing

International Nuclear Information System (INIS)

Mishima, K.; Yamashita, K.

2011-01-01

Graphical abstract: The two-state Deutsch-Jozsa algortihm used to demonstrate the utility of free-time and fixed-end point multi-target optimal control theory. Research highlights: → Free-time and fixed-end point multi-target optimal control theory (FRFP-MTOCT) was constructed. → The features of our theory include optimization of the external time-dependent perturbations with high transition probabilities, that of the temporal duration, the monotonic convergence, and the ability to optimize multiple-laser pulses simultaneously. → The advantage of the theory and a comparison with conventional fixed-time and fixed end-point multi-target optimal control theory (FIFP-MTOCT) are presented by comparing data calculated using the present theory with those published previously [K. Mishima, K. Yamashita, Chem. Phys. 361 (2009) 106]. → The qubit system of our interest consists of two polar NaCl molecules coupled by dipole-dipole interaction. → The calculation examples show that our theory is useful for minor adjustment of the external fields. - Abstract: An extension of free-time and fixed end-point optimal control theory (FRFP-OCT) to monotonically convergent free-time and fixed end-point multi-target optimal control theory (FRFP-MTOCT) is presented. The features of our theory include optimization of the external time-dependent perturbations with high transition probabilities, that of the temporal duration, the monotonic convergence, and the ability to optimize multiple-laser pulses simultaneously. The advantage of the theory and a comparison with conventional fixed-time and fixed end-point multi-target optimal control theory (FIFP-MTOCT) are presented by comparing data calculated using the present theory with those published previously [K. Mishima, K. Yamashita, Chem. Phys. 361, (2009), 106]. The qubit system of our interest consists of two polar NaCl molecules coupled by dipole-dipole interaction. The calculation examples show that our theory is useful for minor

Personalized trajectory matching in spatial networks

KAUST Repository

Shang, Shuo

2013-07-31

With the increasing availability of moving-object tracking data, trajectory search and matching is increasingly important. We propose and investigate a novel problem called personalized trajectory matching (PTM). In contrast to conventional trajectory similarity search by spatial distance only, PTM takes into account the significance of each sample point in a query trajectory. A PTM query takes a trajectory with user-specified weights for each sample point in the trajectory as its argument. It returns the trajectory in an argument data set with the highest similarity to the query trajectory. We believe that this type of query may bring significant benefits to users in many popular applications such as route planning, carpooling, friend recommendation, traffic analysis, urban computing, and location-based services in general. PTM query processing faces two challenges: how to prune the search space during the query processing and how to schedule multiple so-called expansion centers effectively. To address these challenges, a novel two-phase search algorithm is proposed that carefully selects a set of expansion centers from the query trajectory and exploits upper and lower bounds to prune the search space in the spatial and temporal domains. An efficiency study reveals that the algorithm explores the minimum search space in both domains. Second, a heuristic search strategy based on priority ranking is developed to schedule the multiple expansion centers, which can further prune the search space and enhance the query efficiency. The performance of the PTM query is studied in extensive experiments based on real and synthetic trajectory data sets. © 2013 Springer-Verlag Berlin Heidelberg.

Trajectory Control of Rendezvous with Maneuver Target Spacecraft

Science.gov (United States)

Zhou, Zhinqiang

2012-01-01

In this paper, a nonlinear trajectory control algorithm of rendezvous with maneuvering target spacecraft is presented. The disturbance forces on the chaser and target spacecraft and the thrust forces on the chaser spacecraft are considered in the analysis. The control algorithm developed in this paper uses the relative distance and relative velocity between the target and chaser spacecraft as the inputs. A general formula of reference relative trajectory of the chaser spacecraft to the target spacecraft is developed and applied to four different proximity maneuvers, which are in-track circling, cross-track circling, in-track spiral rendezvous and cross-track spiral rendezvous. The closed-loop differential equations of the proximity relative motion with the control algorithm are derived. It is proven in the paper that the tracking errors between the commanded relative trajectory and the actual relative trajectory are bounded within a constant region determined by the control gains. The prediction of the tracking errors is obtained. Design examples are provided to show the implementation of the control algorithm. The simulation results show that the actual relative trajectory tracks the commanded relative trajectory tightly. The predicted tracking errors match those calculated in the simulation results. The control algorithm developed in this paper can also be applied to interception of maneuver target spacecraft and relative trajectory control of spacecraft formation flying.

Two-surface Monte Carlo with basin hopping: quantum mechanical trajectory and multiple stationary points of water cluster.

Science.gov (United States)

Bandyopadhyay, Pradipta

2008-04-07

The efficiency of the two-surface monte carlo (TSMC) method depends on the closeness of the actual potential and the biasing potential used to propagate the system of interest. In this work, it is shown that by combining the basin hopping method with TSMC, the efficiency of the method can be increased by several folds. TSMC with basin hopping is used to generate quantum mechanical trajectory and large number of stationary points of water clusters.

A New Test Unit for Disintegration End-Point Determination of Orodispersible Films.

Science.gov (United States)

Low, Ariana; Kok, Si Ling; Khong, Yuet Mei; Chan, Sui Yung; Gokhale, Rajeev

2015-11-01

No standard time or pharmacopoeia disintegration test method for orodispersible films (ODFs) exists. The USP disintegration test for tablets and capsules poses significant challenges for end-point determination when used for ODFs. We tested a newly developed disintegration test unit (DTU) against the USP disintegration test. The DTU is an accessory to the USP disintegration apparatus. It holds the ODF in a horizontal position, allowing top-view of the ODF during testing. A Gauge R&R study was conducted to assign relative contributions of the total variability from the operator, sample or the experimental set-up. Precision was compared using commercial ODF products in different media. Agreement between the two measurement methods was analysed. The DTU showed improved repeatability and reproducibility compared to the USP disintegration system with tighter standard deviations regardless of operator or medium. There is good agreement between the two methods, with the USP disintegration test giving generally longer disintegration times possibly due to difficulty in end-point determination. The DTU provided clear end-point determination and is suitable for quality control of ODFs during product developmental stage or manufacturing. This may facilitate the development of a standardized methodology for disintegration time determination of ODFs. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

A Measure of Similarity Between Trajectories of Vessels

Directory of Open Access Journals (Sweden)

Le QI

2016-03-01

Full Text Available The measurement of similarity between trajectories of vessels is one of the kernel problems that must be addressed to promote the development of maritime intelligent traffic system (ITS. In this study, a new model of trajectory similarity measurement was established to improve the data processing efficiency in dynamic application and to reflect actual sailing behaviors of vessels. In this model, a feature point detection algorithm was proposed to extract feature points, reduce data storage space and save computational resources. A new synthesized distance algorithm was also created to measure the similarity between trajectories by using the extracted feature points. An experiment was conducted to measure the similarity between the real trajectories of vessels. The growth of these trajectories required measurements to be conducted under different voyages. The results show that the similarity measurement between the vessel trajectories is efficient and correct. Comparison of the synthesized distance with the sailing behaviors of vessels proves that results are consistent with actual situations. The experiment results demonstrate the promising application of the proposed model in studying vessel traffic and in supplying reliable data for the development of maritime ITS.

Analysis of Load-Carrying Capacity for Redundant Free-Floating Space Manipulators in Trajectory Tracking Task

Directory of Open Access Journals (Sweden)

Qingxuan Jia

2014-01-01

Full Text Available The aim of this paper is to analyze load-carrying capacity of redundant free-floating space manipulators (FFSM in trajectory tracking task. Combined with the analysis of influential factors in load-carrying process, evaluation of maximum load-carrying capacity (MLCC is described as multiconstrained nonlinear programming problem. An efficient algorithm based on repeated line search within discontinuous feasible region is presented to determine MLCC for a given trajectory of the end-effector and corresponding joint path. Then, considering the influence of MLCC caused by different initial configurations for the starting point of given trajectory, a kind of maximum payload initial configuration planning method is proposed by using PSO algorithm. Simulations are performed for a particular trajectory tracking task of the 7-DOF space manipulator, of which MLCC is evaluated quantitatively. By in-depth research of the simulation results, significant gap between the values of MLCC when using different initial configurations is analyzed, and the discontinuity of allowable load-carrying capacity is illustrated. The proposed analytical method can be taken as theoretical foundation of feasibility analysis, trajectory optimization, and optimal control of trajectory tracking task in on-orbit load-carrying operations.

Trajectory-based nonadiabatic dynamics with time-dependent density functional theory.

Science.gov (United States)

Curchod, Basile F E; Rothlisberger, Ursula; Tavernelli, Ivano

2013-05-10

Understanding the fate of an electronically excited molecule constitutes an important task for theoretical chemistry, and practical implications range from the interpretation of atto- and femtosecond spectroscopy to the development of light-driven molecular machines, the control of photochemical reactions, and the possibility of capturing sunlight energy. However, many challenging conceptual and technical problems are involved in the description of these phenomena such as 1) the failure of the well-known Born-Oppenheimer approximation; 2) the need for accurate electronic properties such as potential energy surfaces, excited nuclear forces, or nonadiabatic coupling terms; and 3) the necessity of describing the dynamics of the photoexcited nuclear wavepacket. This review provides an overview of the current methods to address points 1) and 3) and shows how time-dependent density functional theory (TDDFT) and its linear-response extension can be used for point 2). First, the derivation of Ehrenfest dynamics and nonadiabatic Bohmian dynamics is discussed and linked to Tully's trajectory surface hopping. Second, the coupling of these trajectory-based nonadiabatic schemes with TDDFT is described in detail with special emphasis on the derivation of the required electronic structure properties. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

VISUAL UAV TRAJECTORY PLAN SYSTEM BASED ON NETWORK MAP

Directory of Open Access Journals (Sweden)

X. L. Li

2012-07-01

Full Text Available The base map of the current software UP-30 using in trajectory plan for Unmanned Aircraft Vehicle is vector diagram. UP-30 draws navigation points manually. But in the field of operation process, the efficiency and the quality of work is influenced because of insufficient information, screen reflection, calculate inconveniently and other factors. If we do this work in indoor, the effect of external factors on the results would be eliminated, the network earth users can browse the free world high definition satellite images through downloading a client software, and can export the high resolution image by standard file format. This brings unprecedented convenient of trajectory plan. But the images must be disposed by coordinate transformation, geometric correction. In addition, according to the requirement of mapping scale ,camera parameters and overlap degree we can calculate exposure hole interval and trajectory distance between the adjacent trajectory automatically . This will improve the degree of automation of data collection. Software will judge the position of next point according to the intersection of the trajectory and the survey area and ensure the position of point according to trajectory distance. We can undertake the points artificially. So the trajectory plan is automatic and flexible. Considering safety, the date can be used in flying after simulating flight. Finally we can export all of the date using a key

Visual Uav Trajectory Plan System Based on Network Map

Science.gov (United States)

Li, X. L.; Lin, Z. J.; Su, G. Z.; Wu, B. Y.

2012-07-01

The base map of the current software UP-30 using in trajectory plan for Unmanned Aircraft Vehicle is vector diagram. UP-30 draws navigation points manually. But in the field of operation process, the efficiency and the quality of work is influenced because of insufficient information, screen reflection, calculate inconveniently and other factors. If we do this work in indoor, the effect of external factors on the results would be eliminated, the network earth users can browse the free world high definition satellite images through downloading a client software, and can export the high resolution image by standard file format. This brings unprecedented convenient of trajectory plan. But the images must be disposed by coordinate transformation, geometric correction. In addition, according to the requirement of mapping scale ,camera parameters and overlap degree we can calculate exposure hole interval and trajectory distance between the adjacent trajectory automatically . This will improve the degree of automation of data collection. Software will judge the position of next point according to the intersection of the trajectory and the survey area and ensure the position of point according to trajectory distance. We can undertake the points artificially. So the trajectory plan is automatic and flexible. Considering safety, the date can be used in flying after simulating flight. Finally we can export all of the date using a key

Radiometric titration of officinal radiopharmaceuticals using radioactive kryptonates as end-point indicators. I

International Nuclear Information System (INIS)

Toelgyessy, J.; Dillinger, P.; Harangozo, M.; Jombik, J.

1980-01-01

A method for the determination of salicylic, acetylsalicylic and benzoic acids in officinal pharmaceutical based on radiometric titration with 0.1 mol.l -1 NaOH was developed. The end-point was detected with the aid of radioactive glass kryptonate. After the end-point, the excess titrant attacks the glass surface layers and this results in releasing 85 Kr, and consequently, in decreasing the radioactivity of the kryptonate employed. The radioactive kryptonate used as an indicator was prepared by the bombardment of glass with accelerated 85 Kr ions. The developed method is simple, accurate and correct. (author)

A combination method of the theory and experiment in determination of cutting force coefficients in ball-end mill processes

Directory of Open Access Journals (Sweden)

Yung-Chou Kao

2015-10-01

Full Text Available In this paper, the cutting force calculation of ball-end mill processing was modeled mathematically. All derivations of cutting forces were directly based on the tangential, radial, and axial cutting force components. In the developed mathematical model of cutting forces, the relationship of average cutting force and the feed per flute was characterized as a linear function. The cutting force coefficient model was formulated by a function of average cutting force and other parameters such as cutter geometry, cutting conditions, and so on. An experimental method was proposed based on the stable milling condition to estimate the cutting force coefficients for ball-end mill. This method could be applied for each pair of tool and workpiece. The developed cutting force model has been successfully verified experimentally with very promising results.

The End of Points

Science.gov (United States)

Feldman, Jo

2018-01-01

Have teachers become too dependent on points? This article explores educators' dependency on their points systems, and the ways that points can distract teachers from really analyzing students' capabilities and achievements. Feldman argues that using a more subjective grading system can help illuminate crucial information about students and what…

Impact of confinement housing on study end-points in the calf model of cryptosporidiosis.

Science.gov (United States)

Graef, Geneva; Hurst, Natalie J; Kidder, Lance; Sy, Tracy L; Goodman, Laura B; Preston, Whitney D; Arnold, Samuel L M; Zambriski, Jennifer A

2018-04-01

Diarrhea is the second leading cause of death in children confinement housing, and Interval Collection (IC), which permits use of box stalls. CFC mimics human challenge model methodology but it is unknown if confinement housing impacts study end-points and if data gathered via this method is suitable for generalization to human populations. Using a modified crossover study design we compared CFC and IC and evaluated the impact of housing on study end-points. At birth, calves were randomly assigned to confinement (n = 14) or box stall housing (n = 9), or were challenged with 5 x 107 C. parvum oocysts, and followed for 10 days. Study end-points included fecal oocyst shedding, severity of diarrhea, degree of dehydration, and plasma cortisol. Calves in confinement had no significant differences in mean log oocysts enumerated per gram of fecal dry matter between CFC and IC samples (P = 0.6), nor were there diurnal variations in oocyst shedding (P = 0.1). Confinement housed calves shed significantly more oocysts (P = 0.05), had higher plasma cortisol (P = 0.001), and required more supportive care (P = 0.0009) than calves in box stalls. Housing method confounds study end-points in the calf model of cryptosporidiosis. Due to increased stress data collected from calves in confinement housing may not accurately estimate the efficacy of chemotherapeutics targeting C. parvum.

Educational Policy Trajectories in an Era of Globalization: Singapore and Cambodia

Science.gov (United States)

Tan, Charlene

2010-01-01

This paper critically discusses the educational policy trajectories of Singapore and Cambodia in an era of globalization. Drawing upon David Johnson's five metaphors to describe the historical and political forces that shape educational policy trajectories, the paper argues that Cambodia's current educational policy trajectory is characterized by…

Free Energy, Enthalpy and Entropy from Implicit Solvent End-Point Simulations.

Science.gov (United States)

Fogolari, Federico; Corazza, Alessandra; Esposito, Gennaro

2018-01-01

Free energy is the key quantity to describe the thermodynamics of biological systems. In this perspective we consider the calculation of free energy, enthalpy and entropy from end-point molecular dynamics simulations. Since the enthalpy may be calculated as the ensemble average over equilibrated simulation snapshots the difficulties related to free energy calculation are ultimately related to the calculation of the entropy of the system and in particular of the solvent entropy. In the last two decades implicit solvent models have been used to circumvent the problem and to take into account solvent entropy implicitly in the solvation terms. More recently outstanding advancement in both implicit solvent models and in entropy calculations are making the goal of free energy estimation from end-point simulations more feasible than ever before. We review briefly the basic theory and discuss the advancements in light of practical applications.

Free Energy, Enthalpy and Entropy from Implicit Solvent End-Point Simulations

Directory of Open Access Journals (Sweden)

Federico Fogolari

2018-02-01

Full Text Available Free energy is the key quantity to describe the thermodynamics of biological systems. In this perspective we consider the calculation of free energy, enthalpy and entropy from end-point molecular dynamics simulations. Since the enthalpy may be calculated as the ensemble average over equilibrated simulation snapshots the difficulties related to free energy calculation are ultimately related to the calculation of the entropy of the system and in particular of the solvent entropy. In the last two decades implicit solvent models have been used to circumvent the problem and to take into account solvent entropy implicitly in the solvation terms. More recently outstanding advancement in both implicit solvent models and in entropy calculations are making the goal of free energy estimation from end-point simulations more feasible than ever before. We review briefly the basic theory and discuss the advancements in light of practical applications.

Context-aware pattern discovery for moving object trajectories

Science.gov (United States)

Sharif, Mohammad; Asghar Alesheikh, Ali; Kaffash Charandabi, Neda

2018-05-01

Movement of point objects are highly sensitive to the underlying situations and conditions during the movement, which are known as contexts. Analyzing movement patterns, while accounting the contextual information, helps to better understand how point objects behave in various contexts and how contexts affect their trajectories. One potential solution for discovering moving objects patterns is analyzing the similarities of their trajectories. This article, therefore, contextualizes the similarity measure of trajectories by not only their spatial footprints but also a notion of internal and external contexts. The dynamic time warping (DTW) method is employed to assess the multi-dimensional similarities of trajectories. Then, the results of similarity searches are utilized in discovering the relative movement patterns of the moving point objects. Several experiments are conducted on real datasets that were obtained from commercial airplanes and the weather information during the flights. The results yielded the robustness of DTW method in quantifying the commonalities of trajectories and discovering movement patterns with 80 % accuracy. Moreover, the results revealed the importance of exploiting contextual information because it can enhance and restrict movements.

A proton point source produced by laser interaction with cone-top-end target

International Nuclear Information System (INIS)

Yu, Jinqing; Jin, Xiaolin; Zhou, Weimin; Zhao, Zongqing; Yan, Yonghong; Li, Bin; Hong, Wei; Gu, Yuqiu

2012-01-01

In this paper, we propose a proton point source by the interaction of laser and cone-top-end target and investigate it by two-dimensional particle-in-cell (2D-PIC) simulations as the proton point sources are well known for higher spatial resolution of proton radiography. Our results show that the relativistic electrons are guided to the rear of the cone-top-end target by the electrostatic charge-separation field and self-generated magnetic field along the profile of the target. As a result, the peak magnitude of sheath field at the rear surface of cone-top-end target is higher compared to common cone target. We test this scheme by 2D-PIC simulation and find the result has a diameter of 0.79λ 0 , an average energy of 9.1 MeV and energy spread less than 35%.

Information resources and the correlation of response patterns between biological end points

Energy Technology Data Exchange (ETDEWEB)

Malling, H.V. [National Institute of Environmental Health Sciences, Research Triangle Park, NC (United States); Wassom, J.S. [Oak Ridge National Laboratory, TN (United States)

1990-12-31

This paper focuses on the analysis of information for mutagenesis, a biological end point that is important in the overall process of assessing possible adverse health effects from chemical exposure. 17 refs.

Simulations of High Speed Fragment Trajectories

Science.gov (United States)

Yeh, Peter; Attaway, Stephen; Arunajatesan, Srinivasan; Fisher, Travis

2017-11-01

Flying shrapnel from an explosion are capable of traveling at supersonic speeds and distances much farther than expected due to aerodynamic interactions. Predicting the trajectories and stable tumbling modes of arbitrary shaped fragments is a fundamental problem applicable to range safety calculations, damage assessment, and military technology. Traditional approaches rely on characterizing fragment flight using a single drag coefficient, which may be inaccurate for fragments with large aspect ratios. In our work we develop a procedure to simulate trajectories of arbitrary shaped fragments with higher fidelity using high performance computing. We employ a two-step approach in which the force and moment coefficients are first computed as a function of orientation using compressible computational fluid dynamics. The force and moment data are then input into a six-degree-of-freedom rigid body dynamics solver to integrate trajectories in time. Results of these high fidelity simulations allow us to further understand the flight dynamics and tumbling modes of a single fragment. Furthermore, we use these results to determine the validity and uncertainty of inexpensive methods such as the single drag coefficient model.

Trajectory data privacy protection based on differential privacy mechanism

Science.gov (United States)

Gu, Ke; Yang, Lihao; Liu, Yongzhi; Liao, Niandong

2018-05-01

In this paper, we propose a trajectory data privacy protection scheme based on differential privacy mechanism. In the proposed scheme, the algorithm first selects the protected points from the user’s trajectory data; secondly, the algorithm forms the polygon according to the protected points and the adjacent and high frequent accessed points that are selected from the accessing point database, then the algorithm calculates the polygon centroids; finally, the noises are added to the polygon centroids by the differential privacy method, and the polygon centroids replace the protected points, and then the algorithm constructs and issues the new trajectory data. The experiments show that the running time of the proposed algorithms is fast, the privacy protection of the scheme is effective and the data usability of the scheme is higher.

GeoTravel: Harvesting Ambient Geographic Footprints from GPS Trajectories

OpenAIRE

Liew, Li Ching; Goh, Ong Sing

2014-01-01

This study is about harvesting point of interest from GPS trajectories. Trajectories are the paths that moving objects move by follow through space in a function of time while GPS trajectories generally are point-sequences with geographic coordinates, time stamp, speed and heading. User can get information from GPS enable device. For example, user can acquire present location, search the information around them and design driving routes to a destination and thus design travel itineraries. By ...

Trajectory Planning with Pose Feedback for a Dual-Arm Space Robot

Directory of Open Access Journals (Sweden)

Yicheng Liu

2016-01-01

Full Text Available In order to obtain high precision path tracking for a dual-arm space robot, a trajectory planning method with pose feedback is proposed to be introduced into the design process in this paper. Firstly, pose error kinematic models are derived from the related kinematics and desired pose command for the end-effector and the base, respectively. On this basis, trajectory planning with pose feedback is proposed from a control perspective. Theoretical analyses show that the proposed trajectory planning algorithm can guarantee that pose error converges to zero exponentially for both the end-effector and the base when the robot is out of singular configuration. Compared with the existing algorithms, the proposed algorithm can lead to higher precision path tracking for the end-effector. Furthermore, the algorithm renders the system good anti-interference property for the base. Simulation results demonstrate the effectiveness of the proposed trajectory planning algorithm.

The Oklahoma Attorney General's Task Force report on the State of End-of-Life Health Care, 2005.

Science.gov (United States)

Edmondson, W A Drew

2005-05-01

This article includes the recommendations submitted by the 15 members of the Oklahoma Attorney General's Task Force in their Report on the State of End-of-Life Health Care. The task force was created on April 21, 2004, and their report was accepted by Attorney General W.A. Drew Edmondson at a press conference April 11, 2005. It has been forwarded to members of the Oklahoma Legislature, relevant state agencies and organizations with an invitation to join with members of the task force to continue efforts to improve end-of-life care for Oklahomans. Copies of the report are available upon request to the Office of Attorney General.

A Trajectory Generation Method Based on Edge Detection for Auto-Sealant Cartesian Robot

Directory of Open Access Journals (Sweden)

Eka Samsul Maarif

2014-07-01

Full Text Available This paper presents algorithm ingenerating trajectory for sealant process using captured image. Cartesian robot as auto-sealant in manufacturing process has increased productivity, reduces human error and saves time. But, different sealant path in many engine models means not only different trajectory but also different program. Therefore robot with detection ability to generate its own trajectory is needed. This paper describes best lighting technique in capturing image and applies edge detection in trajectory generation as the solution. The algorithm comprises image capturing, Canny edge detection, integral projection in localizing outer most edge, scanning coordinates, and generating vector direction codes. The experiment results show that the best technique is diffuse lighting at 10 Cd. The developed method gives connected point to point trajectory which forms sealant path with a point to next point distance is equal to 90° motor rotation. Directional movement for point to point trajectory is controlled by generated codes which are ready to be sent by serial communication to robot controller as instruction for motors which actuate axes X and Y directions.

Describing chaotic attractors: Regular and perpetual points

Science.gov (United States)

Dudkowski, Dawid; Prasad, Awadhesh; Kapitaniak, Tomasz

2018-03-01

We study the concepts of regular and perpetual points for describing the behavior of chaotic attractors in dynamical systems. The idea of these points, which have been recently introduced to theoretical investigations, is thoroughly discussed and extended into new types of models. We analyze the correlation between regular and perpetual points, as well as their relation with phase space, showing the potential usefulness of both types of points in the qualitative description of co-existing states. The ability of perpetual points in finding attractors is indicated, along with its potential cause. The location of chaotic trajectories and sets of considered points is investigated and the study on the stability of systems is shown. The statistical analysis of the observing desired states is performed. We focus on various types of dynamical systems, i.e., chaotic flows with self-excited and hidden attractors, forced mechanical models, and semiconductor superlattices, exhibiting the universality of appearance of the observed patterns and relations.

MULTI-DIMENSIONAL PATTERN DISCOVERY OF TRAJECTORIES USING CONTEXTUAL INFORMATION

Directory of Open Access Journals (Sweden)

M. Sharif

2017-10-01

Full Text Available Movement of point objects are highly sensitive to the underlying situations and conditions during the movement, which are known as contexts. Analyzing movement patterns, while accounting the contextual information, helps to better understand how point objects behave in various contexts and how contexts affect their trajectories. One potential solution for discovering moving objects patterns is analyzing the similarities of their trajectories. This article, therefore, contextualizes the similarity measure of trajectories by not only their spatial footprints but also a notion of internal and external contexts. The dynamic time warping (DTW method is employed to assess the multi-dimensional similarities of trajectories. Then, the results of similarity searches are utilized in discovering the relative movement patterns of the moving point objects. Several experiments are conducted on real datasets that were obtained from commercial airplanes and the weather information during the flights. The results yielded the robustness of DTW method in quantifying the commonalities of trajectories and discovering movement patterns with 80 % accuracy. Moreover, the results revealed the importance of exploiting contextual information because it can enhance and restrict movements.

Multi-Dimensional Pattern Discovery of Trajectories Using Contextual Information

Science.gov (United States)

Sharif, M.; Alesheikh, A. A.

2017-10-01

Movement of point objects are highly sensitive to the underlying situations and conditions during the movement, which are known as contexts. Analyzing movement patterns, while accounting the contextual information, helps to better understand how point objects behave in various contexts and how contexts affect their trajectories. One potential solution for discovering moving objects patterns is analyzing the similarities of their trajectories. This article, therefore, contextualizes the similarity measure of trajectories by not only their spatial footprints but also a notion of internal and external contexts. The dynamic time warping (DTW) method is employed to assess the multi-dimensional similarities of trajectories. Then, the results of similarity searches are utilized in discovering the relative movement patterns of the moving point objects. Several experiments are conducted on real datasets that were obtained from commercial airplanes and the weather information during the flights. The results yielded the robustness of DTW method in quantifying the commonalities of trajectories and discovering movement patterns with 80 % accuracy. Moreover, the results revealed the importance of exploiting contextual information because it can enhance and restrict movements.

Kinetic titration with differential thermometric determination of the end-point.

Science.gov (United States)

Sajó, I

1968-06-01

A method has been described for the determination of concentrations below 10(-4)M by applying catalytic reactions and using thermometric end-point determination. A reference solution, identical with the sample solution except for catalyst, is titrated with catalyst solution until the rates of reaction become the same, as shown by a null deflection on a galvanometer connected via bridge circuits to two opposed thermistors placed in the solutions.

Distinguished trajectories in time dependent vector fields

OpenAIRE

Madrid, J. A. Jimenez; Mancho, Ana M.

2008-01-01

We introduce a new definition of distinguished trajectory that generalizes the concepts of fixed point and periodic orbit to aperiodic dynamical systems. This new definition is valid for identifying distinguished trajectories with hyperbolic and nonhyperbolic types of stability. The definition is implemented numerically and the procedure consists of determining a path of limit coordinates. It has been successfully applied to known examples of distinguished trajectories. In the context of high...

3D trajectories re-construction of droplets ejected in controlled tungsten melting studies in ASDEX Upgrade

International Nuclear Information System (INIS)

Yang, Zhongshi; Krieger, K.; Lunt, T.; Brochard, F.; Briancon, J.-L.; Neu, R.; Dux, R.; Janzer, A.; Potzel, S.; Pütterich, T.

2013-01-01

Two fast visible range camera systems with vertically and tangentially oriented crossed viewing fields in the divertor region of ASDEX Upgrade were used to observe tungsten (W) droplets ejected from a melting W-pin into the divertor plasma. To obtain the spatial (3D) trajectories of the tungsten droplets, the trajectory of a given droplet in the (2D) camera image coordinate system was derived for each view separately. From these data, the 3D droplet position was derived by computing the shortest line segment connecting crossed viewing chords to a given droplet taking the centre coordinate of the line segment as actual coordinate. The experimental error of the derived position was estimated from the length of the connecting line segment. In the toroidal direction, the computed trajectories can be described by an analytical transport model for the droplets assuming an initial droplet diameter in the range of 60–100 μm. In the vertical direction the vertical distance droplets travelled when reaching the edge of the viewing field also agrees with the model predictions. However, discrepancies are found with respect to the time point whence a droplet reverts its initial downwards motion due to centrifugal forces exceeding gravity and plasma generated force components

Non-Born-Oppenheimer trajectories with self-consistent decay of mixing

International Nuclear Information System (INIS)

Zhu Chaoyuan; Jasper, Ahren W.; Truhlar, Donald G.

2004-01-01

A semiclassical trajectory method, called the self-consistent decay of mixing (SCDM) method, is presented for the treatment of electronically nonadiabatic dynamics. The SCDM method is a modification of the semiclassical Ehrenfest (SE) method (also called the semiclassical time-dependent self-consistent-field method) that solves the problem of unphysical mixed final states by including decay-of-mixing terms in the equations for the evolution of the electronic state populations. These terms generate a force, called the decoherent force (or dephasing force), that drives the electronic component of each trajectory toward a pure state. Results for several mixed quantum-classical methods, in particular the SCDM, SE, and natural-decay-of-mixing methods and several trajectory surface hopping methods, are compared to the results of accurate quantum mechanical calculations for 12 cases involving five different fully dimensional triatomic model systems. The SCDM method is found to be the most accurate of the methods tested. The method should be useful for the simulation of photochemical reactions

Trajectory Optimization Based on Multi-Interval Mesh Refinement Method

Directory of Open Access Journals (Sweden)

Ningbo Li

2017-01-01

Full Text Available In order to improve the optimization accuracy and convergence rate for trajectory optimization of the air-to-air missile, a multi-interval mesh refinement Radau pseudospectral method was introduced. This method made the mesh endpoints converge to the practical nonsmooth points and decreased the overall collocation points to improve convergence rate and computational efficiency. The trajectory was divided into four phases according to the working time of engine and handover of midcourse and terminal guidance, and then the optimization model was built. The multi-interval mesh refinement Radau pseudospectral method with different collocation points in each mesh interval was used to solve the trajectory optimization model. Moreover, this method was compared with traditional h method. Simulation results show that this method can decrease the dimensionality of nonlinear programming (NLP problem and therefore improve the efficiency of pseudospectral methods for solving trajectory optimization problems.

Simulation-Based Early Prediction of Rocket, Artillery, and Mortar Trajectories and Real-Time Optimization for Counter-RAM Systems

Directory of Open Access Journals (Sweden)

Arash Ramezani

2017-01-01

Full Text Available The threat imposed by terrorist attacks is a major hazard for military installations, for example, in Iraq and Afghanistan. The large amounts of rockets, artillery projectiles, and mortar grenades (RAM that are available pose serious threats to military forces. An important task for international research and development is to protect military installations and implement an accurate early warning system against RAM threats on conventional computer systems in out-of-area field camps. This work presents a method for determining the trajectory, caliber, and type of a projectile based on the estimation of the ballistic coefficient. A simulation-based optimization process is presented that enables iterative adjustment of predicted trajectories in real time. Analytical and numerical methods are used to reduce computing time for out-of-area missions and low-end computer systems. A GUI is programmed to present the results. It allows for comparison between predicted and actual trajectories. Finally, different aspects and restrictions for measuring the quality of the results are discussed.

Long-term future risk of severe exacerbations: Distinct 5-year trajectories of problematic asthma.

Science.gov (United States)

Yii, A C A; Tan, J H Y; Lapperre, T S; Chan, A K W; Low, S Y; Ong, T H; Tan, K L; Chotirmall, S H; Sterk, P J; Koh, M S

2017-09-01

Assessing future risk of exacerbations is an important component of asthma management. Existing studies have investigated short- but not long-term risk. Problematic asthma patients with unfavorable long-term disease trajectory and persistently frequent severe exacerbations need to be identified early to guide treatment. To identify distinct trajectories of severe exacerbation rates among "problematic asthma" patients and develop a risk score to predict the most unfavorable trajectory. Severe exacerbation rates over five years for 177 "problematic asthma" patients presenting to a specialist asthma clinic were tracked. Distinct trajectories of severe exacerbation rates were identified using group-based trajectory modeling. Baseline predictors of trajectory were identified and used to develop a clinical risk score for predicting the most unfavorable trajectory. Three distinct trajectories were found: 58.5% had rare intermittent severe exacerbations ("infrequent"), 32.0% had frequent severe exacerbations at baseline but improved subsequently ("nonpersistently frequent"), and 9.5% exhibited persistently frequent severe exacerbations, with the highest incidence of near-fatal asthma ("persistently frequent"). A clinical risk score composed of ≥2 severe exacerbations in the past year (+2 points), history of near-fatal asthma (+1 point), body mass index ≥25kg/m 2 (+1 point), obstructive sleep apnea (+1 point), gastroesophageal reflux (+1 point), and depression (+1 point) was predictive of the "persistently frequent" trajectory (area under the receiver operating characteristic curve: 0.84, sensitivity 72.2%, specificity 81.1% using cutoff ≥3 points). The trajectories and clinical risk score had excellent performance in an independent validation cohort. Patients with problematic asthma follow distinct illness trajectories over a period of five years. We have derived and validated a clinical risk score that accurately identifies patients who will have persistently

Trajectory grouping structure

Directory of Open Access Journals (Sweden)

Maike Buchin

2015-03-01

Full Text Available The collective motion of a set of moving entities like people, birds, or other animals, is characterized by groups arising, merging, splitting, and ending. Given the trajectories of these entities, we define and model a structure that captures all of such changes using the Reeb graph, a concept from topology. The trajectory grouping structure has three natural parameters that allow more global views of the data in group size, group duration, and entity inter-distance. We prove complexity bounds on the maximum number of maximal groups that can be present, and give algorithms to compute the grouping structure efficiently. We also study how the trajectory grouping structure can be made robust, that is, how brief interruptions of groups can be disregarded in the global structure, adding a notion of persistence to the structure. Furthermore, we showcase the results of experiments using data generated by the NetLogo flocking model and from the Starkey project. The Starkey data describe the movement of elk, deer, and cattle. Although there is no ground truth for the grouping structure in this data, the experiments show that the trajectory grouping structure is plausible and has the desired effects when changing the essential parameters. Our research provides the first complete study of trajectory group evolvement, including combinatorial,algorithmic, and experimental results.

Clustering Trajectories by Relevant Parts for Air Traffic Analysis.

Science.gov (United States)

Andrienko, Gennady; Andrienko, Natalia; Fuchs, Georg; Garcia, Jose Manuel Cordero

2018-01-01

Clustering of trajectories of moving objects by similarity is an important technique in movement analysis. Existing distance functions assess the similarity between trajectories based on properties of the trajectory points or segments. The properties may include the spatial positions, times, and thematic attributes. There may be a need to focus the analysis on certain parts of trajectories, i.e., points and segments that have particular properties. According to the analysis focus, the analyst may need to cluster trajectories by similarity of their relevant parts only. Throughout the analysis process, the focus may change, and different parts of trajectories may become relevant. We propose an analytical workflow in which interactive filtering tools are used to attach relevance flags to elements of trajectories, clustering is done using a distance function that ignores irrelevant elements, and the resulting clusters are summarized for further analysis. We demonstrate how this workflow can be useful for different analysis tasks in three case studies with real data from the domain of air traffic. We propose a suite of generic techniques and visualization guidelines to support movement data analysis by means of relevance-aware trajectory clustering.

Multiple-Sensor Discrimination of Closely-Spaced Objects on a Ballistic Trajectory

Science.gov (United States)

2015-05-18

Modeling Two-body orbit dynamics was utilized to generate ballistic trajectories between the desired burnout and reentry points. The dispersion of object...trajectories within the target complex was achieved by varying the velocity of each object at the burnout points. The generated trajectories served...utilized as it removes several limitations associated with using the Euclidean distance mainly that it accounts for the scaling of the coordinate

Critical point dewetting: competition between the gravity and the dispersion force

International Nuclear Information System (INIS)

Ohmasa, Y; Takahashi, S; Fujii, K; Yao, M

2008-01-01

Near the critical temperature of an immiscible binary liquid system, a solid substrate is usually covered completely by one of the liquid phases. This phenomenon is called the 'critical point wetting , which is predicted by Cahn in 1977, and have been confirmed for many fluid systems experimentally. However, we found that liquid Se-Tl system on a quartz substrate does not show the critical point wetting near the liquid-liquid critical point. On a contrary, when the temperature goes down from the critical point, a Se-rich wetting film intrudes between the Tl-rich bulk liquid and the quartz wall. This result is a clear evidence of the 'critical point dewetting' phenomenon. It is suggested from a theoretical consideration that the critical point dewetting takes place as a result of the competition between the long-range dispersion force and the gravity

Quantum dynamics modeled by interacting trajectories

Science.gov (United States)

Cruz-Rodríguez, L.; Uranga-Piña, L.; Martínez-Mesa, A.; Meier, C.

2018-03-01

We present quantum dynamical simulations based on the propagation of interacting trajectories where the effect of the quantum potential is mimicked by effective pseudo-particle interactions. The method is applied to several quantum systems, both for bound and scattering problems. For the bound systems, the quantum ground state density and zero point energy are shown to be perfectly obtained by the interacting trajectories. In the case of time-dependent quantum scattering, the Eckart barrier and uphill ramp are considered, with transmission coefficients in very good agreement with standard quantum calculations. Finally, we show that via wave function synthesis along the trajectories, correlation functions and energy spectra can be obtained based on the dynamics of interacting trajectories.

Differences in context and feedback result in different trajectories and adaptation strategies in reaching.

Directory of Open Access Journals (Sweden)

Fritzie Arce

Full Text Available Computational models of motor control have often explained the straightness of horizontal planar reaching movements as a consequence of optimal control. Departure from rectilinearity is thus regarded as sub-optimal. Here we examine if subjects may instead select to make curved trajectories following adaptation to force fields and visuomotor rotations. Separate subjects adapted to force fields with or without visual feedback of their hand trajectory and were retested after 24 hours. Following adaptation, comparable accuracies were achieved in two ways: with visual feedback, adapted trajectories in force fields were straight whereas without it, they remained curved. The results suggest that trajectory shape is not always straight, but is also influenced by the calibration of available feedback signals for the state estimation required by the task. In a follow-up experiment, where additional subjects learned a visuomotor rotation immediately after force field, the trajectories learned in force fields (straight or curved were transferred when directions of the perturbations were similar but not when directions were opposing. This demonstrates a strong bias by prior experience to keep using a recently acquired control policy that continues to produce successful performance inspite of differences in tasks and feedback conditions. On relearning of force fields on the second day, facilitation by intervening visuomotor rotations occurred only when required motor adjustments and calibration of feedback signals were similar in both tasks. These results suggest that both the available feedback signals and prior history of learning influence the choice and maintenance of control policy during adaptations.

End point detection in ion milling processes by sputter-induced optical emission spectroscopy

International Nuclear Information System (INIS)

Lu, C.; Dorian, M.; Tabei, M.; Elsea, A.

1984-01-01

The characteristic optical emission from the sputtered material during ion milling processes can provide an unambiguous indication of the presence of the specific etched species. By monitoring the intensity of a representative emission line, the etching process can be precisely terminated at an interface. Enhancement of the etching end point is possible by using a dual-channel photodetection system operating in a ratio or difference mode. The installation of the optical detection system to an existing etching chamber has been greatly facilitated by the use of optical fibers. Using a commercial ion milling system, experimental data for a number of etching processes have been obtained. The result demonstrates that sputter-induced optical emission spectroscopy offers many advantages over other techniques in detecting the etching end point of ion milling processes

MSGD: Scalable back-end for indoor magnetic field-based GraphSLAM

OpenAIRE

Gao, C; Harle, Robert Keith

2017-01-01

Simultaneous Localisation and Mapping (SLAM) systems that recover the trajectory of a robot or mobile device are characterised by a front-end and back-end. The front-end uses sensor observations to identify loop closures; the back-end optimises the estimated trajectory to be consistent with these closures. The GraphSLAM framework formulates the back-end problem as a graph-based optimisation on a pose graph. This paper describes a back-end system optimised for very dense sequence-based lo...

Confinement in Melts of Chains with Junction Points, but No Ends

Science.gov (United States)

Foster, Mark; He, Qiming; Zhou, Yang; Zhang, Fan; Huang, Chongwen; Narayanan, Suresh

Measurements of surface fluctuations of 4-arm star and ''8-shaped'' analogs of the same polystyrene (PS) chain show that elimination of chain ends is much more important in dictating the fragility in a thin film than is the introduction of a branch point in the molecule. Both the viscosities derived from surface fluctuations and rheological measurements for the 8-shaped PS manifest a lower value than the 4-arm star PS analog, with the discrepancy increasing as the temperature approaches the glass transition temperature, Tg , bulk. Comparison among different chain topologies shows the effect of the number of chain ends and junction point on the viscosity. The viscosity behavior of the 8-shaped PS is quite different from that of the star analog, but similar to that of the simple cycle analog. The fragility of the 8-shaped molecule in the thin film is reduced relative to that in the bulk, manifesting a nanoconfinement effect. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.

Dissipative quantum trajectories in complex space: Damped harmonic oscillator

Energy Technology Data Exchange (ETDEWEB)

Chou, Chia-Chun, E-mail: ccchou@mx.nthu.edu.tw

2016-10-15

Dissipative quantum trajectories in complex space are investigated in the framework of the logarithmic nonlinear Schrödinger equation. The logarithmic nonlinear Schrödinger equation provides a phenomenological description for dissipative quantum systems. Substituting the wave function expressed in terms of the complex action into the complex-extended logarithmic nonlinear Schrödinger equation, we derive the complex quantum Hamilton–Jacobi equation including the dissipative potential. It is shown that dissipative quantum trajectories satisfy a quantum Newtonian equation of motion in complex space with a friction force. Exact dissipative complex quantum trajectories are analyzed for the wave and solitonlike solutions to the logarithmic nonlinear Schrödinger equation for the damped harmonic oscillator. These trajectories converge to the equilibrium position as time evolves. It is indicated that dissipative complex quantum trajectories for the wave and solitonlike solutions are identical to dissipative complex classical trajectories for the damped harmonic oscillator. This study develops a theoretical framework for dissipative quantum trajectories in complex space.

Dissipative quantum trajectories in complex space: Damped harmonic oscillator

International Nuclear Information System (INIS)

Chou, Chia-Chun

2016-01-01

Dissipative quantum trajectories in complex space are investigated in the framework of the logarithmic nonlinear Schrödinger equation. The logarithmic nonlinear Schrödinger equation provides a phenomenological description for dissipative quantum systems. Substituting the wave function expressed in terms of the complex action into the complex-extended logarithmic nonlinear Schrödinger equation, we derive the complex quantum Hamilton–Jacobi equation including the dissipative potential. It is shown that dissipative quantum trajectories satisfy a quantum Newtonian equation of motion in complex space with a friction force. Exact dissipative complex quantum trajectories are analyzed for the wave and solitonlike solutions to the logarithmic nonlinear Schrödinger equation for the damped harmonic oscillator. These trajectories converge to the equilibrium position as time evolves. It is indicated that dissipative complex quantum trajectories for the wave and solitonlike solutions are identical to dissipative complex classical trajectories for the damped harmonic oscillator. This study develops a theoretical framework for dissipative quantum trajectories in complex space.

Unexpected properties of the centrifugal force

International Nuclear Information System (INIS)

Abramowicz, M.A.

1990-01-01

Contrary to what is stated in the Newtonian dynamics, rotation of a reference frame is not sufficient for the occurrence of the centrifugal force. Instead, the necessary and sufficient condition is a motion along a path different from that of a photon trajectory in space. This calls for a rather fundamental change in understanding of the very nature of the centrifugal force. It also has important practical physical consequences: in a strong gravitational field, where light trajectories are substantially curved, centrifugal force is much weaker than the Newtonian theory predicts. In addition, when there are closed (circular) photon trajectories in space, the centrifugal force may reverse its direction - it attracts towards the rotation axis!. The weakening of the centrifugal force in strong gravitational fields and the reversal of its direction in the neighbourhood of close photon trajectories in space fully and clearly explain puzzling examples of counter intuitive behaviour of dynamical effects of rotation found previously by several authors: e.g. reversal of the ellipticity behaviour of the relativistic Maclaurin spheroids (Chandrasekhar and Miller, 1974), reversal of the viscous torque action (Anderson and Lemos, 1988), or the fact that rotation increases internal pressure of a sufficiently compact star (Abramowicz and Wagoner, 1974). Weakening of the centrifugal force implies that rotating neutron stars are less oblate (and probably more stable) than the Newtonian theory predicts. This is important for the recently discussed question of how fast can pulsars spin. (author). 23 refs, 3 figs

Unexpected properties of the centrifugal force

International Nuclear Information System (INIS)

Abramowicz, M.A.

1990-01-01

Contrary to what is stated in the Newtonian dynamics, rotation of a reference frame is not sufficient for the occurrence of the centrifugal force. Instead, the necessary and sufficient condition is a motion along a path different from that of a photon trajectory in space. This calls for a rather fundamental change in understanding of the very nature of the centrifugal force. It also has important practical physical consequences: in a strong gravitational field, where light trajectories are substantially curved, centrifugal force is much weaker than the Newtonian theory predicts. In addition, when there are closed (circular) photon trajectories in space, the centrifugal force may reverse its direction - it attracts towards the rotation axis. The weakening of the centrifugal force in strong gravitational fields and the reversal of its direction in the neighborhood of close photon trajectories in space fully and clearly explain puzzling examples of counter intuitive behaviour of dynamical effects of rotation found previously by several authors: e.g. reversal of the ellipticity behaviour of the relativistic Maclaurin spheroids (Chandrasekhar and Miller, 1974), reversal of the viscous torque action (Anderson and Lemos, 1988) or the fact that rotation increases internal pressure of a sufficiently compact star (Abramowicz and Wagoner, 1974). Weakening of the centrifugal force implies that rotating neutron stars are less oblate (and probably more stable) than the Newtonian theory predicts. This is important for the recently discussed question of how fast can pulsars spins. (author). 31 refs, 3 figs

The trajectory control in the SLC linac

International Nuclear Information System (INIS)

Hsu, I.C.; Adolphsen, C.E.; Himel, T.M.; Seeman, J.T.

1991-05-01

Due to wake field effects, the trajectories of accelerated beams in the Linac should be well maintained to avoid severe beam breakup. In order to maintain a small emittance at the end of the Linac, the tolerance on the trajectory deviations become tighter when the beam intensities increase. The existing two beam trajectory correction method works well when the theoretical model agrees with the real machine lattice. Unknown energy deviations along the linac as well as wake field effects can cause the real lattice to deviate from the model. This makes the trajectory correction difficult. Several automated procedures have been developed to solve these problems. They are: an automated procedure to frequently steer the whole Linac by dividing the Linac into several small regions; an automated procedure to empirically correct the model to fit the real lattice and eight trajectory correcting feedback loops along the linac and steering through the collimator region with restricted corrector strengths and a restricted number of correctors. 6 refs., 2 figs

A New Methodology for Solving Trajectory Planning and Dynamic Load-Carrying Capacity of a Robot Manipulator

Directory of Open Access Journals (Sweden)

Wanjin Guo

2016-01-01

Full Text Available A new methodology using a direct method for obtaining the best found trajectory planning and maximum dynamic load-carrying capacity (DLCC is presented for a 5-degree of freedom (DOF hybrid robot manipulator. A nonlinear constrained multiobjective optimization problem is formulated with four objective functions, namely, travel time, total energy involved in the motion, joint jerks, and joint acceleration. The vector of decision variables is defined by the sequence of the time-interval lengths associated with each two consecutive via-points on the desired trajectory of the 5-DOF robot generalized coordinates. Then this vector of decision variables is computed in order to minimize the cost function (which is the weighted sum of these four objective functions subject to constraints on joint positions, velocities, acceleration, jerks, forces/torques, and payload mass. Two separate approaches are proposed to deal with the trajectory planning problem and the maximum DLCC calculation for the 5-DOF robot manipulator using an evolutionary optimization technique. The adopted evolutionary algorithm is the elitist nondominated sorting genetic algorithm (NSGA-II. A numerical application is performed for obtaining best found solutions of trajectory planning and maximum DLCC calculation for the 5-DOF hybrid robot manipulator.

Dynamic optimization of dead-end membrane filtration

NARCIS (Netherlands)

Blankert, B.; Betlem, Bernardus H.L.; Roffel, B.; Marquardt, Wolfgang; Pantelides, Costas

2006-01-01

An operating strategy aimed at minimizing the energy consumption during the filtration phase of dead-end membrane filtration has been formulated. A method allowing fast calculation of trajectories is used to allow incorporation in a hierarchical optimization scheme. The optimal trajectory can be

Calculation of trajectory parameters of long pass in basketball.

Directory of Open Access Journals (Sweden)

Charikova K.M.

2011-08-01

Full Text Available Values of a ball's flight trajectory parameters depending on a distance of long pass, a corner of a ball's start and height of a throwing point are submitted in article. Coordinates of reference points installation for training to long pass with an optimum trajectory of a ball's flight are designed. Requirements to simulators design are determined. Corners of ball's long pass performance in various game situations are recommended.

Complex dynamics in diatomic molecules. Part II: Quantum trajectories

International Nuclear Information System (INIS)

Yang, C.-D.; Weng, H.-J.

2008-01-01

The second part of this paper deals with quantum trajectories in diatomic molecules, which has not been considered before in the literature. Morse potential serves as a more accurate function than a simple harmonic oscillator for illustrating a realistic picture about the vibration of diatomic molecules. However, if we determine molecular dynamics by integrating the classical force equations derived from a Morse potential, we will find that the resulting trajectories do not consist with the probabilistic prediction of quantum mechanics. On the other hand, the quantum trajectory determined by Bohmian mechanics [Bohm D. A suggested interpretation of the quantum theory in terms of hidden variable. Phys. Rev. 1952;85:166-179] leads to the conclusion that a diatomic molecule is motionless in all its vibrational eigen-states, which also contradicts probabilistic prediction of quantum mechanics. In this paper, we point out that the quantum trajectory of a diatomic molecule completely consistent with quantum mechanics does exist and can be solved from the quantum Hamilton equations of motion derived in Part I, which is based on a complex-space formulation of fractal spacetime [El Naschie MS. A review of E-Infinity theory and the mass spectrum of high energy particle physics. Chaos, Solitons and Fractals 2004;19:209-36; El Naschie MS. E-Infinity theory - some recent results and new interpretations. Chaos, Solitons and Fractals 2006;29:845-853; El Naschie MS. The concepts of E-infinity. An elementary introduction to the cantorian-fractal theory of quantum physics. Chaos, Solitons and Fractals 2004;22:495-511; El Naschie MS. SU(5) grand unification in a transfinite form. Chaos, Solitons and Fractals 2007;32:370-374; Nottale L. Fractal space-time and microphysics: towards a theory of scale relativity. Singapore: World Scientific; 1993; Ord G. Fractal space time and the statistical mechanics of random works. Chaos, Soiltons and Fractals 1996;7:821-843] approach to quantum

Evolution of Randomized Trials in Advanced/Metastatic Soft Tissue Sarcoma: End Point Selection, Surrogacy, and Quality of Reporting.

Science.gov (United States)

Zer, Alona; Prince, Rebecca M; Amir, Eitan; Abdul Razak, Albiruni

2016-05-01

Randomized controlled trials (RCTs) in soft tissue sarcoma (STS) have used varying end points. The surrogacy of intermediate end points, such as progression-free survival (PFS), response rate (RR), and 3-month and 6-month PFS (3moPFS and 6moPFS) with overall survival (OS), remains unknown. The quality of efficacy and toxicity reporting in these studies is also uncertain. A systematic review of systemic therapy RCTs in STS was performed. Surrogacy between intermediate end points and OS was explored using weighted linear regression for the hazard ratio for OS with the hazard ratio for PFS or the odds ratio for RR, 3moPFS, and 6moPFS. The quality of reporting for efficacy and toxicity was also evaluated. Fifty-two RCTs published between 1974 and 2014, comprising 9,762 patients, met the inclusion criteria. There were significant correlations between PFS and OS (R = 0.61) and between RR and OS (R = 0.51). Conversely, there were nonsignificant correlations between 3moPFS and 6moPFS with OS. A reduction in the use of RR as the primary end point was observed over time, favoring time-based events (P for trend = .02). In 14% of RCTs, the primary end point was not met, but the study was reported as being positive. Toxicity was comprehensively reported in 47% of RCTs, whereas 14% inadequately reported toxicity. In advanced STS, PFS and RR seem to be appropriate surrogates for OS. There is poor correlation between OS and both 3moPFS and 6moPFS. As such, caution is urged with the use of these as primary end points in randomized STS trials. The quality of toxicity reporting and interpretation of results is suboptimal. © 2016 by American Society of Clinical Oncology.

Radiometric titration of officinal radiopharmaceuticals using radioactive kryptonates as end-point indicators. II. Citric, tartaric, undecylenic acids

Energy Technology Data Exchange (ETDEWEB)

Harangozo, M.; Jombik, J.; Schiller, P. (Komenskeho Univ., Bratislava (Czechoslovakia). Farmaceuticka Fakulta); Toelgyessy, J. (Slovenska Vysoka Skola Technicka, Bratislava (Czechoslovakia). Chemickotechnologicka Fakulta)

1981-01-01

A method for the determination of citric, tartaric and undecylenic acids based on radiometric titration with 0.1 or 0.05 mole.l/sup -1/ NaOH was developed. As an indicator of the end point, radioactive kryptonate of glass was used. Experimental technique, results of determinations as well as other possible applications of the radioactive kryptonate of glass for end point determination in alkalimetric analyses of officinal pharmaceuticals are discussed.

Spatio-Temporal Pattern Mining on Trajectory Data Using Arm

Science.gov (United States)

Khoshahval, S.; Farnaghi, M.; Taleai, M.

2017-09-01

Preliminary mobile was considered to be a device to make human connections easier. But today the consumption of this device has been evolved to a platform for gaming, web surfing and GPS-enabled application capabilities. Embedding GPS in handheld devices, altered them to significant trajectory data gathering facilities. Raw GPS trajectory data is a series of points which contains hidden information. For revealing hidden information in traces, trajectory data analysis is needed. One of the most beneficial concealed information in trajectory data is user activity patterns. In each pattern, there are multiple stops and moves which identifies users visited places and tasks. This paper proposes an approach to discover user daily activity patterns from GPS trajectories using association rules. Finding user patterns needs extraction of user's visited places from stops and moves of GPS trajectories. In order to locate stops and moves, we have implemented a place recognition algorithm. After extraction of visited points an advanced association rule mining algorithm, called Apriori was used to extract user activity patterns. This study outlined that there are useful patterns in each trajectory that can be emerged from raw GPS data using association rule mining techniques in order to find out about multiple users' behaviour in a system and can be utilized in various location-based applications.

CFD Analysis of Swing of Cricket Ball and Trajectory Prediction

Science.gov (United States)

G, Jithin; Tom, Josin; Ruishikesh, Kamat; Jose, Jyothish; Kumar, Sanjay

2013-11-01

This work aims to understand the aerodynamics associated with the flight and swing of a cricket ball and predict its flight trajectory over the course of the game: at start (smooth ball) and as the game progresses (rough ball). Asymmetric airflow over the ball due to seam orientation and surface roughness can cause flight deviation (swing). The values of Drag, Lift and Side forces which are crucial for determining the trajectory of the ball were found with the help of FLUENT using the standard K- ɛ model. Analysis was done to study how the ball velocity, spin imparted to be ball and the tilt of the seam affects the movement of the ball through air. The governing force balance equations in 3 dimensions in combination a MATLAB code which used Heun's method was used for obtaining the trajectory of the ball. The conditions for the conventional swing and reverse swing to occur were deduced from the analysis and found to be in alignment with the real life situation. Critical seam angle for maximum swing and transition speed for normal to reverse swing were found out. The obtained trajectories were compared to real life hawk eye trajectories for validation. The analysis results were in good agreement with the real life situation.

Quality control for electron beam processing of polymeric materials by end-point analysis

International Nuclear Information System (INIS)

DeGraff, E.; McLaughlin, W.L.

1981-01-01

Properties of certain plastics, e.g. polytetrafluoroethylene, polyethylene, ethylene vinyl acetate copolymer, can be modified selectively by ionizing radiation. One of the advantages of this treatment over chemical methods is better control of the process and the end-product properties. The most convenient method of dosimetry for monitoring quality control is post-irradiation evaluation of the plastic itself, e.g., melt index and melt point determination. It is shown that by proper calibration in terms of total dose and sufficiently reproducible radiation effects, such product test methods provide convenient and meaningful analyses. Other appropriate standardized analytical methods include stress-crack resistance, stress-strain-to-fracture testing and solubility determination. Standard routine dosimetry over the dose and dose rate ranges of interest confirm that measured product end points can be correlated with calibrated values of absorbed dose in the product within uncertainty limits of the measurements. (author)

The effect of drive frequency and set point amplitude on tapping forces in atomic force microscopy: simulation and experiment

International Nuclear Information System (INIS)

Legleiter, Justin

2009-01-01

In tapping mode atomic force microscopy (AFM), a sharp probe tip attached to an oscillating cantilever is allowed to intermittently strike a surface. By raster scanning the probe while monitoring the oscillation amplitude of the cantilever via a feedback loop, topographical maps of surfaces with nanoscale resolution can be acquired. While numerous studies have employed numerical simulations to elucidate the time-resolved tapping force between the probe tip and surface, until recent technique developments, specific read-outs from such models could not be experimentally verified. In this study, we explore, via numerical simulation, the impact of imaging parameters, i.e. set point ratio and drive frequency as a function of resonance, on time-varying tip-sample force interactions, which are directly compared to reconstructed tapping forces from real AFM experiments. As the AFM model contains a feedback loop allowing for the simulation of the entire scanning process, we further explore the impact that various tip-sample force have on the entire imaging process.

Standardized End Point Definitions for Coronary Intervention Trials: The Academic Research Consortium-2 Consensus Document.

Science.gov (United States)

Garcia-Garcia, Hector M; McFadden, Eugène P; Farb, Andrew; Mehran, Roxana; Stone, Gregg W; Spertus, John; Onuma, Yoshinobu; Morel, Marie-Angèle; van Es, Gerrit-Anne; Zuckerman, Bram; Fearon, William F; Taggart, David; Kappetein, Arie-Pieter; Krucoff, Mitchell W; Vranckx, Pascal; Windecker, Stephan; Cutlip, Donald; Serruys, Patrick W

2018-06-14

The Academic Research Consortium (ARC)-2 initiative revisited the clinical and angiographic end point definitions in coronary device trials, proposed in 2007, to make them more suitable for use in clinical trials that include increasingly complex lesion and patient populations and incorporate novel devices such as bioresorbable vascular scaffolds. In addition, recommendations for the incorporation of patient-related outcomes in clinical trials are proposed. Academic Research Consortium-2 is a collaborative effort between academic research organizations in the United States and Europe, device manufacturers, and European, US, and Asian regulatory bodies. Several in-person meetings were held to discuss the changes that have occurred in the device landscape and in clinical trials and regulatory pathways in the last decade. The consensus-based end point definitions in this document are endorsed by the stakeholders of this document and strongly advocated for clinical trial purposes. This Academic Research Consortium-2 document provides further standardization of end point definitions for coronary device trials, incorporating advances in technology and knowledge. Their use will aid interpretation of trial outcomes and comparison among studies, thus facilitating the evaluation of the safety and effectiveness of these devices.

Single-Molecule Force Spectroscopy Trajectories of a Single Protein and Its Polyproteins Are Equivalent: A Direct Experimental Validation Based on A Small Protein NuG2.

Science.gov (United States)

Lei, Hai; He, Chengzhi; Hu, Chunguang; Li, Jinliang; Hu, Xiaodong; Hu, Xiaotang; Li, Hongbin

2017-05-22

Single-molecule force spectroscopy (SMFS) has become a powerful tool in investigating the mechanical unfolding/folding of proteins at the single-molecule level. Polyproteins made of tandem identical repeats have been widely used in atomic force microscopy (AFM)-based SMFS studies, where polyproteins not only serve as fingerprints to identify single-molecule stretching events, but may also improve statistics of data collection. However, the inherent assumption of such experiments is that all the domains in the polyprotein are equivalent and one SMFS trajectory of stretching a polyprotein made of n domains is equivalent to n trajectories of stretching a single domain. Such an assumption has not been validated experimentally. Using a small protein NuG2 and its polyprotein (NuG2) 4 as model systems, here we use optical trapping (OT) to directly validate this assumption. Our results show that OT experiments on NuG2 and (NuG2) 4 lead to identical parameters describing the unfolding and folding kinetics of NuG2, demonstrating that indeed stretching a polyprotein of NuG2 is equivalent to stretching single NuG2 in force spectroscopy experiments and thus validating the use of polyproteins in SMFS experiments. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Local parametric instability near elliptic points in vortex flows under shear deformation

Energy Technology Data Exchange (ETDEWEB)

Koshel, Konstantin V., E-mail: kvkoshel@poi.dvo.ru [Pacific Oceanological Institute, FEB RAS, 43, Baltiyskaya Street, Vladivostok 690041 (Russian Federation); Institute of Applied Mathematics, FEB RAS, 7, Radio Street, Vladivostok 690022 (Russian Federation); Far Eastern Federal University, 8, Sukhanova Street, Vladivostok 690950 (Russian Federation); Ryzhov, Eugene A., E-mail: ryzhovea@gmail.com [Pacific Oceanological Institute, FEB RAS, 43, Baltiyskaya Street, Vladivostok 690041 (Russian Federation)

2016-08-15

The dynamics of two point vortices embedded in an oscillatory external flow consisted of shear and rotational components is addressed. The region associated with steady-state elliptic points of the vortex motion is established to experience local parametric instability. The instability forces the point vortices with initial positions corresponding to the steady-state elliptic points to move in spiral-like divergent trajectories. This divergent motion continues until the nonlinear effects suppress their motion near the region associated with the steady-state separatrices. The local parametric instability is then demonstrated not to contribute considerably to enhancing the size of the chaotic motion regions. Instead, the size of the chaotic motion region mostly depends on overlaps of the nonlinear resonances emerging in the perturbed system.

End-point construction and systematic titration error in linear titration curves-complexation reactions

NARCIS (Netherlands)

Coenegracht, P.M.J.; Duisenberg, A.J.M.

The systematic titration error which is introduced by the intersection of tangents to hyperbolic titration curves is discussed. The effects of the apparent (conditional) formation constant, of the concentration of the unknown component and of the ranges used for the end-point construction are

Merchandising at the point of sale: differential effect of end of aisle and islands

Directory of Open Access Journals (Sweden)

Álvaro Garrido-Morgado

2015-01-01

Full Text Available Merchandising at point of sale comprises a set of techniques aimed at encouraging the purchase at the point of sale. This paper analyzes the impact on sales of two of these techniques, especially used in the context of non-specialized food stores and rarely distinguished in academic research: (1 the presentation of product in the ends of the aisles or main aisles, leading from the side aisle access and, (2 the presentation of the product in islands within the main aisles. This research combines cross-sectional and longitudinal data and analyzes specific information on sales and commercial stimulus for all references in two large categories of products from a hypermarket over ten weeks. Results show that both the ends of aisle and the islands have a positive effect on sales and their relative importance depends on the nature of the category analyzed. There are also greater synergies between ends of aisle and price promotions. Finally, the results provide some evidence into the impact of the extension or termination of these merchandising stimuli.

Interplanetary Trajectory Design for the Asteroid Robotic Redirect Mission Alternate Approach Trade Study

Science.gov (United States)

Merrill, Raymond Gabriel; Qu, Min; Vavrina, Matthew A.; Englander, Jacob A.; Jones, Christopher A.

2014-01-01

This paper presents mission performance analysis methods and results for the Asteroid Robotic Redirect Mission (ARRM) option to capture a free standing boulder on the surface of a 100 m or larger NEA. It details the optimization and design of heliocentric low-thrust trajectories to asteroid targets for the ARRM solar electric propulsion spacecraft. Extensive searches were conducted to determine asteroid targets with large pick-up mass potential and potential observation opportunities. Interplanetary trajectory approximations were developed in method based tools for Itokawa, Bennu, 1999 JU3, and 2008 EV5 and were validated by end-to-end integrated trajectories.

Advancing nursing science through health trajectory research: an introduction.

Science.gov (United States)

Wyman, Jean F; Henly, Susan J

2011-01-01

The Minnesota Center for Health Trajectory Research has focused on developing ways to better understand how interventions influence health trajectories during transitional, acute, or chronic health challenges across the life span. The health trajectory perspective advances nursing science by providing a person-centered point of view that emphasizes change in health over time within individuals, families, groups, or communities. Theoretical considerations and statistical modeling approaches used in studying health trajectories, along with exemplars from nursing research studies from this special issue of Nursing Research, are highlighted.

Force and Motion Characteristics of Contamination Particles near the High Voltage End of UHVDC Insulator

Directory of Open Access Journals (Sweden)

Lei Lan

2017-07-01

Full Text Available It is important to reveal the relations of physical factors to deposition of contaminants on insulator. In this paper, the simulation model of high voltage end of insulator was established to study the force and motion characteristics of particles affected by electric force and airflow drag force near the ultra-high voltage direct current (UHVDC insulator. By finite element method, the electric field was set specially to be similar to the one near practical insulator, the steady fluid field was simulated. The electric force and air drag force were loaded on the uniformly charged particles. The characteristics of the two forces on particles, the relationship between quantity of electric charge on particles and probability of particles contacting the insulator were analyzed. It was found that, near the sheds, airflow drag force on particles is significantly greater than electric force with less electric charge. As the charge multiplies, electric force increases linearly, airflow drag force grows more slowly. There is a trend that the magnitude of electric force and drag force is going to similar. Meanwhile, the probability of particles contacting the insulator is increased too. However, at a certain level of charge which has different value with different airflow velocity, the contact probability has extremum here. After exceeding the value, as the charge increasing, the contact probability decreases gradually.

Evaluating Trajectory Queries over Imprecise Location Data

DEFF Research Database (Denmark)

Xie, Scott, Xike; Cheng, Reynold; Yiu, Man Lung

2012-01-01

Trajectory queries, which retrieve nearby objects for every point of a given route, can be used to identify alerts of potential threats along a vessel route, or monitor the adjacent rescuers to a travel path. However, the locations of these objects (e.g., threats, succours) may not be precisely...... obtained due to hardware limitations of measuring devices, as well as the constantly-changing nature of the external environment. Ignoring data uncertainty can render low query quality, and cause undesirable consequences such as missing alerts of threats and poor response time in rescue operations. Also......, the query is quite time-consuming, since all the points on the trajectory are considered. In this paper, we study how to efficiently evaluate trajectory queries over imprecise location data, by proposing a new concept called the u-bisector. In general, the u-bisector is an extension of bisector to handle...

Optimal trajectories of aircraft and spacecraft

Science.gov (United States)

Miele, A.

1990-01-01

Work done on algorithms for the numerical solutions of optimal control problems and their application to the computation of optimal flight trajectories of aircraft and spacecraft is summarized. General considerations on calculus of variations, optimal control, numerical algorithms, and applications of these algorithms to real-world problems are presented. The sequential gradient-restoration algorithm (SGRA) is examined for the numerical solution of optimal control problems of the Bolza type. Both the primal formulation and the dual formulation are discussed. Aircraft trajectories, in particular, the application of the dual sequential gradient-restoration algorithm (DSGRA) to the determination of optimal flight trajectories in the presence of windshear are described. Both take-off trajectories and abort landing trajectories are discussed. Take-off trajectories are optimized by minimizing the peak deviation of the absolute path inclination from a reference value. Abort landing trajectories are optimized by minimizing the peak drop of altitude from a reference value. Abort landing trajectories are optimized by minimizing the peak drop of altitude from a reference value. The survival capability of an aircraft in a severe windshear is discussed, and the optimal trajectories are found to be superior to both constant pitch trajectories and maximum angle of attack trajectories. Spacecraft trajectories, in particular, the application of the primal sequential gradient-restoration algorithm (PSGRA) to the determination of optimal flight trajectories for aeroassisted orbital transfer are examined. Both the coplanar case and the noncoplanar case are discussed within the frame of three problems: minimization of the total characteristic velocity; minimization of the time integral of the square of the path inclination; and minimization of the peak heating rate. The solution of the second problem is called nearly-grazing solution, and its merits are pointed out as a useful

A piezo motor based on a new principle with high output force, rigidity and integrity: The Tuna Drive

Science.gov (United States)

Liu, Xiaolong; Lu, Qingyou

2012-11-01

We present a linear piezoelectric motor as simple as one piezoelectric scanner tube (PST) spring-clamping a central shaft at both ends with roughly equal clamping forces. The clamping points are aligned with ±X electrodes at one end and ±Y electrodes at the other end. Thus, the ±X (or ±Y) push-pull motions of the PST can cause the push-pull motions of the clamping points on the shaft (called push-pull rubbing), which reduces the total dynamic friction force at one (or the other) end of the PST. This new piezo motor advances one step by fast push-pull rubbing at one end while slowly retracting the PST followed by fast push-pull rubbing at the other end while slowly elongating the PST. Apart from the obvious advantages of simplicity, rigidity, integrity, etc., we will also show that this motor can produce a large output force, which we believe is because of the huge drop of the clamping friction force when the push-pull rubbing occurs.

Soft modes at the critical end point in the chiral effective models

International Nuclear Information System (INIS)

Fujii, Hirotsugu; Ohtani, Munehisa

2004-01-01

At the critical end point in QCD phase diagram, the scalar, vector and entropy susceptibilities are known to diverge. The dynamic origin of this divergence is identified within the chiral effective models as softening of a hydrodynamic mode of the particle-hole-type motion, which is a consequence of the conservation law of the baryon number and the energy. (author)

Uneven batch data alignment with application to the control of batch end-product quality.

Science.gov (United States)

Wan, Jian; Marjanovic, Ognjen; Lennox, Barry

2014-03-01

Batch processes are commonly characterized by uneven trajectories due to the existence of batch-to-batch variations. The batch end-product quality is usually measured at the end of these uneven trajectories. It is necessary to align the time differences for both the measured trajectories and the batch end-product quality in order to implement statistical process monitoring and control schemes. Apart from synchronizing trajectories with variable lengths using an indicator variable or dynamic time warping, this paper proposes a novel approach to align uneven batch data by identifying short-window PCA&PLS models at first and then applying these identified models to extend shorter trajectories and predict future batch end-product quality. Furthermore, uneven batch data can also be aligned to be a specified batch length using moving window estimation. The proposed approach and its application to the control of batch end-product quality are demonstrated with a simulated example of fed-batch fermentation for penicillin production. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

Trajectories of Intimate Partner Violence Victimization

Directory of Open Access Journals (Sweden)

Kevin M. Swartout

2012-08-01

Full Text Available Introduction: The purposes of this study were to assess the extent to which latent trajectories of female intimate partner violence (IPV victimization exist; and, if so, use negative childhood experiences to predict trajectory membership.Methods: We collected data from 1,575 women at 5 time-points regarding experiences during adolescence and their 4 years of college. We used latent class growth analysis to fit a series of personcentered, longitudinal models ranging from 1 to 5 trajectories. Once the best-fitting model was selected, we used negative childhood experience variables—sexual abuse, physical abuse, and witnessing domestic violence—to predict most-likely trajectory membership via multinomial logistic regression.Results: A 5-trajectory model best fit the data both statistically and in terms of interpretability. The trajectories across time were interpreted as low or no IPV, low to moderate IPV, moderate to low IPV, high to moderate IPV, and high and increasing IPV, respectively. Negative childhood experiences differentiated trajectory membership, somewhat, with childhood sexual abuse as a consistent predictor of membership in elevated IPV trajectories.Conclusion: Our analyses show how IPV risk changes over time and in different ways. These differential patterns of IPV suggest the need for prevention strategies tailored for women that consider victimization experiences in childhood and early adulthood. [West J Emerg Med. 2012;13(3:272–277.

EVALUATING CONTINUOUS-TIME SLAM USING A PREDEFINED TRAJECTORY PROVIDED BY A ROBOTIC ARM

Directory of Open Access Journals (Sweden)

B. Koch

2017-09-01

Full Text Available Recently published approaches to SLAM algorithms process laser sensor measurements and output a map as a point cloud of the environment. Often the actual precision of the map remains unclear, since SLAMalgorithms apply local improvements to the resulting map. Unfortunately, it is not trivial to compare the performance of SLAMalgorithms objectively, especially without an accurate ground truth. This paper presents a novel benchmarking technique that allows to compare a precise map generated with an accurate ground truth trajectory to a map with a manipulated trajectory which was distorted by different forms of noise. The accurate ground truth is acquired by mounting a laser scanner on an industrial robotic arm. The robotic arm is moved on a predefined path while the position and orientation of the end-effector tool are monitored. During this process the 2D profile measurements of the laser scanner are recorded in six degrees of freedom and afterwards used to generate a precise point cloud of the test environment. For benchmarking, an offline continuous-time SLAM algorithm is subsequently applied to remove the inserted distortions. Finally, it is shown that the manipulated point cloud is reversible to its previous state and is slightly improved compared to the original version, since small errors that came into account by imprecise assumptions, sensor noise and calibration errors are removed as well.

Evaluating Continuous-Time Slam Using a Predefined Trajectory Provided by a Robotic Arm

Science.gov (United States)

Koch, B.; Leblebici, R.; Martell, A.; Jörissen, S.; Schilling, K.; Nüchter, A.

2017-09-01

Recently published approaches to SLAM algorithms process laser sensor measurements and output a map as a point cloud of the environment. Often the actual precision of the map remains unclear, since SLAMalgorithms apply local improvements to the resulting map. Unfortunately, it is not trivial to compare the performance of SLAMalgorithms objectively, especially without an accurate ground truth. This paper presents a novel benchmarking technique that allows to compare a precise map generated with an accurate ground truth trajectory to a map with a manipulated trajectory which was distorted by different forms of noise. The accurate ground truth is acquired by mounting a laser scanner on an industrial robotic arm. The robotic arm is moved on a predefined path while the position and orientation of the end-effector tool are monitored. During this process the 2D profile measurements of the laser scanner are recorded in six degrees of freedom and afterwards used to generate a precise point cloud of the test environment. For benchmarking, an offline continuous-time SLAM algorithm is subsequently applied to remove the inserted distortions. Finally, it is shown that the manipulated point cloud is reversible to its previous state and is slightly improved compared to the original version, since small errors that came into account by imprecise assumptions, sensor noise and calibration errors are removed as well.

SPATIO-TEMPORAL PATTERN MINING ON TRAJECTORY DATA USING ARM

Directory of Open Access Journals (Sweden)

S. Khoshahval

2017-09-01

Full Text Available Preliminary mobile was considered to be a device to make human connections easier. But today the consumption of this device has been evolved to a platform for gaming, web surfing and GPS-enabled application capabilities. Embedding GPS in handheld devices, altered them to significant trajectory data gathering facilities. Raw GPS trajectory data is a series of points which contains hidden information. For revealing hidden information in traces, trajectory data analysis is needed. One of the most beneficial concealed information in trajectory data is user activity patterns. In each pattern, there are multiple stops and moves which identifies users visited places and tasks. This paper proposes an approach to discover user daily activity patterns from GPS trajectories using association rules. Finding user patterns needs extraction of user’s visited places from stops and moves of GPS trajectories. In order to locate stops and moves, we have implemented a place recognition algorithm. After extraction of visited points an advanced association rule mining algorithm, called Apriori was used to extract user activity patterns. This study outlined that there are useful patterns in each trajectory that can be emerged from raw GPS data using association rule mining techniques in order to find out about multiple users’ behaviour in a system and can be utilized in various location-based applications.

A sandwiched piezoelectric transducer with flex end-caps for energy harvesting in large force environments

International Nuclear Information System (INIS)

Kuang, Yang; Daniels, Alice; Zhu, Meiling

2017-01-01

This paper presents a sandwiched piezoelectric transducer (SPT) for energy harvesting in large force environments with increased load capacity and electric power output. The SPT uses (1) flex end-caps to amplify the applied load force so as to increase its power output and (2) a sandwiched piezoelectric-substrate structure to reduce the stress concentration in the piezoelectric material so as to increase the load capacity. A coupled piezoelectric-circuit finite element model (CPC-FEM) was developed, which is able to directly predict the electric power output of the SPT connected to a load resistor. The CPC-FEM was used to study the effects of various parameters of the SPT on the performance to obtain an optimal design. These parameters included the substrate thickness, the end-cap material and thickness, the electrode length, the joint length, the end-cap internal angle and the PZT thickness. A prototype with optimised parameters was tested on a loading machine, and the experimental results were compared with simulation. A good agreement was observed between simulation and experiment. When subjected to a 1 kN 2 Hz sinusoidal force applied by the loading machine, the SPT produced an average power of 4.68 mW. The application of the SPT as a footwear energy harvester was demonstrated by fitting the SPT into a boot and performing the tests on a treadmill, and the SPT generated an average power of 2.5 mW at a walking speed of 4.8 km h −1 . (paper)

Minimum distance determination between consecutive carriers in the gamma irradiator IR-200 K trajectory

International Nuclear Information System (INIS)

Achmad Suntoro

2014-01-01

A design to determine the minimum distance between the consecutive carriers at the trajectory of gamma irradiators IR-200K is implemented. Equilibrium between centrifugal force of a moving carrier in circular trajectory and its gravity force as well as carrier dimensions are used as parameters in determining such a minimum distance. The minimum distance between the consecutive carriers in the design is defined 1.2 meters. The distance is 11.5% greater than the minimum distance theoretically calculated, namely 1,076 meters. Errors tolerance in construction/installation of the trajectory and other unexpected things during irradiator's operation are part of the consideration to enlarge the minimum distance from its theoretical value. The distance between the consecutive carriers will not affect throughput and efficiency of using radiation due to the straight trajectory segments do not need to follow such the minimum distance between the carriers, as the trajectory segments around the i radiation sources are straight. (author)

New supervised learning theory applied to cerebellar modeling for suppression of variability of saccade end points.

Science.gov (United States)

Fujita, Masahiko

2013-06-01

A new supervised learning theory is proposed for a hierarchical neural network with a single hidden layer of threshold units, which can approximate any continuous transformation, and applied to a cerebellar function to suppress the end-point variability of saccades. In motor systems, feedback control can reduce noise effects if the noise is added in a pathway from a motor center to a peripheral effector; however, it cannot reduce noise effects if the noise is generated in the motor center itself: a new control scheme is necessary for such noise. The cerebellar cortex is well known as a supervised learning system, and a novel theory of cerebellar cortical function developed in this study can explain the capability of the cerebellum to feedforwardly reduce noise effects, such as end-point variability of saccades. This theory assumes that a Golgi-granule cell system can encode the strength of a mossy fiber input as the state of neuronal activity of parallel fibers. By combining these parallel fiber signals with appropriate connection weights to produce a Purkinje cell output, an arbitrary continuous input-output relationship can be obtained. By incorporating such flexible computation and learning ability in a process of saccadic gain adaptation, a new control scheme in which the cerebellar cortex feedforwardly suppresses the end-point variability when it detects a variation in saccadic commands can be devised. Computer simulation confirmed the efficiency of such learning and showed a reduction in the variability of saccadic end points, similar to results obtained from experimental data.

Trajectory optimization of multiple quad-rotor UAVs in collaborative assembling task

Directory of Open Access Journals (Sweden)

Chen Yongbo

2016-02-01

Full Text Available A hierarchic optimization strategy based on the offline path planning process and online trajectory planning process is presented to solve the trajectory optimization problem of multiple quad-rotor unmanned aerial vehicles in the collaborative assembling task. Firstly, the path planning process is solved by a novel parallel intelligent optimization algorithm, the central force optimization-genetic algorithm (CFO-GA, which combines the central force optimization (CFO algorithm with the genetic algorithm (GA. Because of the immaturity of the CFO, the convergence analysis of the CFO is completed by the stability theory of the linear time-variant discrete-time systems. The results show that the parallel CFO-GA algorithm converges faster than the parallel CFO and the central force optimization-sequential quadratic programming (CFO-SQP algorithm. Then, the trajectory planning problem is established based on the path planning results. In order to limit the range of the attitude angle and guarantee the flight stability, the optimized object is changed from the ordinary six-degree-of-freedom rigid-body dynamic model to the dynamic model with an inner-loop attitude controller. The results show that the trajectory planning process can be solved by the mature SQP algorithm easily. Finally, the discussion and analysis of the real-time performance of the hierarchic optimization strategy are presented around the group number of the waypoints and the equal interval time.

Trajectory phases of a quantum dot model

International Nuclear Information System (INIS)

Genway, Sam; Hickey, James M; Garrahan, Juan P; Armour, Andrew D

2014-01-01

We present a thermodynamic formalism to study the trajectories of charge transport through a quantum dot coupled to two leads in the resonant-level model. We show that a close analogue of equilibrium phase transitions exists for the statistics of transferred charge; by tuning an appropriate ‘counting field’, crossovers to different trajectory phases are possible. Our description reveals a mapping between the statistics of a given device and current measurements over a range of devices with different dot–lead coupling strengths. Furthermore insight into features of the trajectory phases are found by studying the occupation of the dot conditioned on the transported charge between the leads; this is calculated from first principles using a trajectory biased two-point projective measurement scheme. (paper)

Validation of rearrangement break points identified by paired-end sequencing in natural populations of Drosophila melanogaster.

Science.gov (United States)

Cridland, Julie M; Thornton, Kevin R

2010-01-13

Several recent studies have focused on the evolution of recently duplicated genes in Drosophila. Currently, however, little is known about the evolutionary forces acting upon duplications that are segregating in natural populations. We used a high-throughput, paired-end sequencing platform (Illumina) to identify structural variants in a population sample of African D. melanogaster. Polymerase chain reaction and sequencing confirmation of duplications detected by multiple, independent paired-ends showed that paired-end sequencing reliably uncovered the break points of structural rearrangements and allowed us to identify a number of tandem duplications segregating within a natural population. Our confirmation experiments show that rates of confirmation are very high, even at modest coverage. Our results also compare well with previous studies using microarrays (Emerson J, Cardoso-Moreira M, Borevitz JO, Long M. 2008. Natural selection shapes genome wide patterns of copy-number polymorphism in Drosophila melanogaster. Science. 320:1629-1631. and Dopman EB, Hartl DL. 2007. A portrait of copy-number polymorphism in Drosophila melanogaster. Proc Natl Acad Sci U S A. 104:19920-19925.), which both gives us confidence in the results of this study as well as confirms previous microarray results.We were also able to identify whole-gene duplications, such as a novel duplication of Or22a, an olfactory receptor, and identify copy-number differences in genes previously known to be under positive selection, like Cyp6g1, which confers resistance to dichlorodiphenyltrichloroethane. Several "hot spots" of duplications were detected in this study, which indicate that particular regions of the genome may be more prone to generating duplications. Finally, population frequency analysis of confirmed events also showed an excess of rare variants in our population, which indicates that duplications segregating in the population may be deleterious and ultimately destined to be lost from the

Testing of an End-Point Control Unit Designed to Enable Precision Control of Manipulator-Coupled Spacecraft

Science.gov (United States)

Montgomery, Raymond C.; Ghosh, Dave; Tobbe, Patrick A.; Weathers, John M.; Manouchehri, Davoud; Lindsay, Thomas S.

1994-01-01

This paper presents an end-point control concept designed to enable precision telerobotic control of manipulator-coupled spacecraft. The concept employs a hardware unit (end-point control unit EPCU) that is positioned between the end-effector of the Space Shuttle Remote Manipulator System and the payload. Features of the unit are active compliance (control of the displacement between the end-effector and the payload), to allow precision control of payload motions, and inertial load relief, to prevent the transmission of loads between the end-effector and the payload. This paper presents the concept and studies the active compliance feature using a simulation and hardware. Results of the simulation show the effectiveness of the EPCU in smoothing the motion of the payload. Results are presented from initial, limited tests of a laboratory hardware unit on a robotic arm testbed at the l Space Flight Center. Tracking performance of the arm in a constant speed automated retraction and extension maneuver of a heavy payload with and without the unit active is compared for the design speed and higher speeds. Simultaneous load reduction and tracking performance are demonstrated using the EPCU.

Classical trajectories and quantum field theory

International Nuclear Information System (INIS)

Vitiello, Giuseppe; Istituto Nazionale di Fisica Nucleare, Salerno

2005-01-01

The density matrix and the Wigner function formalism requires the doubling of the degrees of freedom in quantum mechanics (QM) and quantum field theory (QFT). The doubled degrees of freedom play the role of the thermal bath or environment degrees of freedom and are entangled with the system degrees of freedom. They also account for quantum noise in the fluctuating random forces in the system-environment coupling. The algebraic structure of QFT turns out to be the one of the deformed Hopf algebra. In such a frame, the trajectories in the space of the unitarily inequivalent representations of the canonical commutation relations turn out to be classical trajectories and, under convenient conditions, they may exhibit properties typical of classical chaotic trajectories in nonlinear dynamics. The quantum Brownian motion and the two-slit experiment in QM are discussed in connection with the doubling of the degrees of freedom. (author)

Developmental trajectories of bullying and associated factors.

Science.gov (United States)

Pepler, Debra; Jiang, Depeng; Craig, Wendy; Connolly, Jennifer

2008-01-01

Trajectories in bullying through adolescence were studied along with individual, family, and peer relationship factors. At the outset, participants' ages ranged from 10 to 14; 74% identified as European Canadian with the remainder from diverse backgrounds. With 8 waves of data over 7 years, 871 students (466 girls and 405 boys) were studied to reveal 4 trajectories: 9.9% reported consistently high levels of bullying, 13.4% reported early moderate levels desisting to almost no bullying at the end of high school, 35.1% reported consistently moderate levels, and 41.6% almost never reported bullying. Students who bullied had elevated risks in individual, parent, and peer relationship domains. Risk profiles and trajectories provide direction for interventions to curtail the development of power and aggression in relationships.

The Effects of Reducing Preparation Time on the Execution of Intentionally Curved Trajectories: Optimization and Geometrical Analysis

Directory of Open Access Journals (Sweden)

Dovrat Kohen

2017-06-01

Full Text Available When subjects are intentionally preparing a curved trajectory, they are engaged in a time-consuming trajectory planning process that is separate from target selection. To investigate the construction of such a plan, we examined the effect of artificially shortening preparation time on the performance of intentionally curved trajectories using the Timed Response task that enforces initiation of movements prematurely. Fifteen subjects performed obstacle avoidance movements toward one of four targets that were presented 25 or 350 ms before the “go” signal, imposing short and long preparation time conditions with mean values of 170 ms and 493 ms, respectively. While trajectories with short preparation times showed target specificity at their onset, they were significantly more variable and showed larger angular deviations from the lines connecting their initial position and the target, compared to the trajectories with long preparation times. Importantly, the trajectories of the short preparation time movements still reached their end-point targets accurately, with comparable movement durations. We hypothesize that success in the short preparation time condition is a result of an online control mechanism that allows further refinement of the plan during its execution and study this control mechanism with a novel trajectory analysis approach using minimum jerk optimization and geometrical modeling approaches. Results show a later agreement of the short preparation time trajectories with the optimal minimum jerk trajectory, accompanied by a later initiation of a parabolic segment. Both observations are consistent with the existence of an online trajectory planning process.Our results suggest that when preparation time is not sufficiently long, subjects execute a more variable and less optimally prepared initial trajectory and exploit online control mechanisms to refine their actions on the fly.

The Effects of Reducing Preparation Time on the Execution of Intentionally Curved Trajectories: Optimization and Geometrical Analysis

Science.gov (United States)

Kohen, Dovrat; Karklinsky, Matan; Meirovitch, Yaron; Flash, Tamar; Shmuelof, Lior

2017-01-01

When subjects are intentionally preparing a curved trajectory, they are engaged in a time-consuming trajectory planning process that is separate from target selection. To investigate the construction of such a plan, we examined the effect of artificially shortening preparation time on the performance of intentionally curved trajectories using the Timed Response task that enforces initiation of movements prematurely. Fifteen subjects performed obstacle avoidance movements toward one of four targets that were presented 25 or 350 ms before the “go” signal, imposing short and long preparation time conditions with mean values of 170 ms and 493 ms, respectively. While trajectories with short preparation times showed target specificity at their onset, they were significantly more variable and showed larger angular deviations from the lines connecting their initial position and the target, compared to the trajectories with long preparation times. Importantly, the trajectories of the short preparation time movements still reached their end-point targets accurately, with comparable movement durations. We hypothesize that success in the short preparation time condition is a result of an online control mechanism that allows further refinement of the plan during its execution and study this control mechanism with a novel trajectory analysis approach using minimum jerk optimization and geometrical modeling approaches. Results show a later agreement of the short preparation time trajectories with the optimal minimum jerk trajectory, accompanied by a later initiation of a parabolic segment. Both observations are consistent with the existence of an online trajectory planning process.Our results suggest that when preparation time is not sufficiently long, subjects execute a more variable and less optimally prepared initial trajectory and exploit online control mechanisms to refine their actions on the fly. PMID:28706478

Dynamics of solar magnetic fields. VI. Force-free magnetic fields and motions of magnetic foot-points

International Nuclear Information System (INIS)

Low, B.C.; Nakagawa, Y.

1975-01-01

A mathematical model is developed to consider the evolution of force-free magnetic fields in relation to the displacements of their foot-points. For a magnetic field depending on only two Cartesian coordinates and time, the problem reduces to solving a nonlinear elliptic partial differential equation. As illustration of the physical process, two specific examples of evolving force-free magnetic fields are examined in detail, one evolving with rising and the other with descending field lines. It is shown that these two contrasting behaviors of the field lines correspond to sheared motions of their foot-points of quite different characters. The physical implications of these two examples of evolving force-free magnetic fields are discussed. (auth)

End Point of the Ultraspinning Instability and Violation of Cosmic Censorship

Science.gov (United States)

Figueras, Pau; Kunesch, Markus; Lehner, Luis; Tunyasuvunakool, Saran

2017-04-01

We determine the end point of the axisymmetric ultraspinning instability of asymptotically flat Myers-Perry black holes in D =6 spacetime dimensions. In the nonlinear regime, this instability gives rise to a sequence of concentric rings connected by segments of black membrane on the rotation plane. The latter become thinner over time, resulting in the formation of a naked singularity in finite asymptotic time and hence a violation of the weak cosmic censorship conjecture in asymptotically flat higher-dimensional spaces.

The timing of control signals underlying fast point-to-point arm movements.

Science.gov (United States)

Ghafouri, M; Feldman, A G

2001-04-01

It is known that proprioceptive feedback induces muscle activation when the facilitation of appropriate motoneurons exceeds their threshold. In the suprathreshold range, the muscle-reflex system produces torques depending on the position and velocity of the joint segment(s) that the muscle spans. The static component of the torque-position relationship is referred to as the invariant characteristic (IC). According to the equilibrium-point (EP) hypothesis, control systems produce movements by changing the activation thresholds and thus shifting the IC of the appropriate muscles in joint space. This control process upsets the balance between muscle and external torques at the initial limb configuration and, to regain the balance, the limb is forced to establish a new configuration or, if the movement is prevented, a new level of static torques. Taken together, the joint angles and the muscle torques generated at an equilibrium configuration define a single variable called the EP. Thus by shifting the IC, control systems reset the EP. Muscle activation and movement emerge following the EP resetting because of the natural physical tendency of the system to reach equilibrium. Empirical and simulation studies support the notion that the control IC shifts and the resulting EP shifts underlying fast point-to-point arm movements are gradual rather than step-like. However, controversies exist about the duration of these shifts. Some studies suggest that the IC shifts cease with the movement offset. Other studies propose that the IC shifts end early in comparison to the movement duration (approximately, at peak velocity). The purpose of this study was to evaluate the duration of the IC shifts underlying fast point-to-point arm movements. Subjects made fast (hand peak velocity about 1.3 m/s) planar arm movements toward different targets while grasping a handle. Hand forces applied to the handle and shoulder/elbow torques were, respectively, measured from a force sensor placed

Is There Space for the Objective Force?

National Research Council Canada - National Science Library

Coffin, Timothy

2003-01-01

The Army has launched itself on a daring trajectory toward the Objective Force. It will transform the Army forces into a more lethal and devastating force through the combination of precision weapons and knowledge-based warfare...

High-Speed Solution of Spacecraft Trajectory Problems Using Taylor Series Integration

Science.gov (United States)

Scott, James R.; Martini, Michael C.

2010-01-01

It has been known for some time that Taylor series (TS) integration is among the most efficient and accurate numerical methods in solving differential equations. However, the full benefit of the method has yet to be realized in calculating spacecraft trajectories, for two main reasons. First, most applications of Taylor series to trajectory propagation have focused on relatively simple problems of orbital motion or on specific problems and have not provided general applicability. Second, applications that have been more general have required use of a preprocessor, which inevitably imposes constraints on computational efficiency. The latter approach includes the work of Berryman et al., who solved the planetary n-body problem with relativistic effects. Their work specifically noted the computational inefficiencies arising from use of a preprocessor and pointed out the potential benefit of manually coding derivative routines. In this Engineering Note, we report on a systematic effort to directly implement Taylor series integration in an operational trajectory propagation code: the Spacecraft N-Body Analysis Program (SNAP). The present Taylor series implementation is unique in that it applies to spacecraft virtually anywhere in the solar system and can be used interchangeably with another integration method. SNAP is a high-fidelity trajectory propagator that includes force models for central body gravitation with N X N harmonics, other body gravitation with N X N harmonics, solar radiation pressure, atmospheric drag (for Earth orbits), and spacecraft thrusting (including shadowing). The governing equations are solved using an eighth-order Runge-Kutta Fehlberg (RKF) single-step method with variable step size control. In the present effort, TS is implemented by way of highly integrated subroutines that can be used interchangeably with RKF. This makes it possible to turn TS on or off during various phases of a mission. Current TS force models include central body

Is Chronic Dialysis the Right Hard Renal End Point To Evaluate Renoprotective Drug Effects?

NARCIS (Netherlands)

Weldegiorgis, Misghina; de Zeeuw, Dick; Dwyer, Jamie P.; Mol, Peter; Heerspink, Hiddo J. L.

2017-01-01

Background and objectives: RRT and doubling of serum creatinine are considered the objective hard end points in nephrology intervention trials. Because both are assumed to reflect changes in the filtration capacity of the kidney, drug effects, if present, are attributed to kidney protection.

Trajectory Generation Method with Convolution Operation on Velocity Profile

Energy Technology Data Exchange (ETDEWEB)

Lee, Geon [Hanyang Univ., Seoul (Korea, Republic of); Kim, Doik [Korea Institute of Science and Technology, Daejeon (Korea, Republic of)

2014-03-15

The use of robots is no longer limited to the field of industrial robots and is now expanding into the fields of service and medical robots. In this light, a trajectory generation method that can respond instantaneously to the external environment is strongly required. Toward this end, this study proposes a method that enables a robot to change its trajectory in real-time using a convolution operation. The proposed method generates a trajectory in real time and satisfies the physical limits of the robot system such as acceleration and velocity limit. Moreover, a new way to improve the previous method, which generates inefficient trajectories in some cases owing to the characteristics of the trapezoidal shape of trajectories, is proposed by introducing a triangle shape. The validity and effectiveness of the proposed method is shown through a numerical simulation and a comparison with the previous convolution method.

Scattering and absorption of particles emitted by a point source in a cluster of point scatterers

International Nuclear Information System (INIS)

Liljequist, D.

2012-01-01

A theory for the scattering and absorption of particles isotropically emitted by a point source in a cluster of point scatterers is described and related to the theory for the scattering of an incident particle beam. The quantum mechanical probability of escape from the cluster in different directions is calculated, as well as the spatial distribution of absorption events within the cluster. A source strength renormalization procedure is required. The average quantum scattering in clusters with randomly shifting scatterer positions is compared to trajectory simulation with the aim of studying the validity of the trajectory method. Differences between the results of the quantum and trajectory methods are found primarily for wavelengths larger than the average distance between nearest neighbour scatterers. The average quantum results include, for example, a local minimum in the number of absorption events at the location of the point source and interference patterns in the angle-dependent escape probability as well as in the distribution of absorption events. The relative error of the trajectory method is in general, though not generally, of similar magnitude as that obtained for beam scattering.

Spatiotemporal Interpolation Methods for Solar Event Trajectories

Science.gov (United States)

Filali Boubrahimi, Soukaina; Aydin, Berkay; Schuh, Michael A.; Kempton, Dustin; Angryk, Rafal A.; Ma, Ruizhe

2018-05-01

This paper introduces four spatiotemporal interpolation methods that enrich complex, evolving region trajectories that are reported from a variety of ground-based and space-based solar observatories every day. Our interpolation module takes an existing solar event trajectory as its input and generates an enriched trajectory with any number of additional time–geometry pairs created by the most appropriate method. To this end, we designed four different interpolation techniques: MBR-Interpolation (Minimum Bounding Rectangle Interpolation), CP-Interpolation (Complex Polygon Interpolation), FI-Interpolation (Filament Polygon Interpolation), and Areal-Interpolation, which are presented here in detail. These techniques leverage k-means clustering, centroid shape signature representation, dynamic time warping, linear interpolation, and shape buffering to generate the additional polygons of an enriched trajectory. Using ground-truth objects, interpolation effectiveness is evaluated through a variety of measures based on several important characteristics that include spatial distance, area overlap, and shape (boundary) similarity. To our knowledge, this is the first research effort of this kind that attempts to address the broad problem of spatiotemporal interpolation of solar event trajectories. We conclude with a brief outline of future research directions and opportunities for related work in this area.

Learning to push and learning to move: The adaptive control of contact forces

Directory of Open Access Journals (Sweden)

Maura eCasadio

2015-11-01

Full Text Available To be successful at manipulating objects one needs to apply simultaneously well controlled movements and contact forces. We present a computational theory of how the brain may successfully generate a vast spectrum of interactive behaviors by combining two independent processes. One process is competent to control movements in free space and the other is competent to control contact forces against rigid constraints. Free space and rigid constraints are singularities at the boundaries of a continuum of mechanical impedance. Within this continuum, forces and motions occur in compatible pairs connected by the equations of Newtonian dynamics. The force applied to an object determines its motion. Conversely, inverse dynamics determine a unique force trajectory from a movement trajectory. In this perspective, we describe motor learning as a process leading to the discovery of compatible force/motion pairs. The learned compatible pairs constitute a local representation of the environment's mechanics. Experiments on force field adaptation have already provided us with evidence that the brain is able to predict and compensate the forces encountered when one is attempting to generate a motion. Here, we tested the theory in the dual case, i.e. when one attempts at applying a desired contact force against a simulated rigid surface. If the surface becomes unexpectedly compliant, the contact point moves as a function of the applied force and this causes the applied force to deviate from its desired value. We found that, through repeated attempts at generating the desired contact force, subjects discovered the unique compatible hand motion. When, after learning, the rigid contact was unexpectedly restored, subjects displayed after effects of learning, consistent with the concurrent operation of a motion control system and a force control system. Together, theory and experiment support a new and broader view of modularity in the coordinated control of forces and

Robotics in hostile environment I. S. I. S. robot - automatic positioning and docking with proximity and force feed back sensors

Energy Technology Data Exchange (ETDEWEB)

Gery, D

1987-01-01

Recent improvements in control command systems and the development of tactile proximity and force feed back sensors make it possible to robotize complex inspection and maintenance operations in hostile environment, which could have not been possible by classical remotely operated manipulators. We describe the I.S.I.S. robot characteristics, the control command system software principles and the tactile and force-torque sensors which have been developed for the different sequences of an hostile environment inspection and repair: access trajectories generation with obstacles shunning, final positioning and docking using parametric algorithms taking into account measurement of the end of arm proximity and force-torque sensors.

Potentiometric end point detection in the EDTA titrimetric determination of gallium

International Nuclear Information System (INIS)

Gopinath, N.; Renuka, M.; Aggarwal, S.K.

2001-01-01

Gallium is titrated in presence of known amount of Fe (III) with EDTA in HNO 3 solution at pH 2 to 3. The end point is detected potentiometrically employing a bright platinum wire - saturated calomel (SCE) reference electrode system, the redox couple being Fe (III) / Fe (II). Since Fe (III) is also titrated by EDTA, it is, therefore, subtracted from titre value to get the EDTA equivalent to gallium only. Precision and accuracy 0.2 to 0.4% was obtained in the results of gallium in the range of 8 to 2 mg. (author)

Resonant forcing of multidimensional chaotic map dynamics.

Science.gov (United States)

Foster, Glenn; Hübler, Alfred W; Dahmen, Karin

2007-03-01

We study resonances of chaotic map dynamics. We use the calculus of variations to determine the additive forcing function that induces the largest response. We find that resonant forcing functions complement the separation of nearby trajectories, in that the product of the displacement of nearby trajectories and the resonant forcing is a conserved quantity. As a consequence, the resonant function will have the same periodicity as the displacement dynamics, and if the displacement dynamics is irregular, then the resonant forcing function will be irregular as well. Furthermore, we show that resonant forcing functions of chaotic systems decrease exponentially, where the rate equals the negative of the largest Lyapunov exponent of the unperturbed system. We compare the response to optimal forcing with random forcing and find that the optimal forcing is particularly effective if the largest Lyapunov exponent is significantly larger than the other Lyapunov exponents. However, if the largest Lyapunov exponent is much larger than unity, then the optimal forcing decreases rapidly and is only as effective as a single-push forcing.

Towards free 3D end-point control for robotic-assisted human reaching using binocular eye tracking.

Science.gov (United States)

Maimon-Dror, Roni O; Fernandez-Quesada, Jorge; Zito, Giuseppe A; Konnaris, Charalambos; Dziemian, Sabine; Faisal, A Aldo

2017-07-01

Eye-movements are the only directly observable behavioural signals that are highly correlated with actions at the task level, and proactive of body movements and thus reflect action intentions. Moreover, eye movements are preserved in many movement disorders leading to paralysis (or amputees) from stroke, spinal cord injury, Parkinson's disease, multiple sclerosis, and muscular dystrophy among others. Despite this benefit, eye tracking is not widely used as control interface for robotic interfaces in movement impaired patients due to poor human-robot interfaces. We demonstrate here how combining 3D gaze tracking using our GT3D binocular eye tracker with custom designed 3D head tracking system and calibration method enables continuous 3D end-point control of a robotic arm support system. The users can move their own hand to any location of the workspace by simple looking at the target and winking once. This purely eye tracking based system enables the end-user to retain free head movement and yet achieves high spatial end point accuracy in the order of 6 cm RMSE error in each dimension and standard deviation of 4 cm. 3D calibration is achieved by moving the robot along a 3 dimensional space filling Peano curve while the user is tracking it with their eyes. This results in a fully automated calibration procedure that yields several thousand calibration points versus standard approaches using a dozen points, resulting in beyond state-of-the-art 3D accuracy and precision.

Au pair trajectories

DEFF Research Database (Denmark)

Dalgas, Karina Märcher

2015-01-01

pair-sending families in the Philippines, this dissertation examines the long-term trajectories of these young Filipinas. It shows how the au pairs’ local and transnational family relations develop over time and greatly influence their life trajectories. A focal point of the study is how au pairs...... that Filipina au pairs see their stay abroad as an avenue of personal development and social recognition, I examine how the au pairs re-position themselves within their families at home through migration, and how they navigate between the often conflicting expectations of participation in the sociality......Since 2000, thousands of young Filipino migrants have come to Denmark as au pairs. Officially, they are there to “broaden their cultural horizons” by living temporarily with a Danish host family, but they also conduct domestic labor in exchange for food and money, which allows them to send...

Radiometric titration of officinal radiopharmaceuticals using radioactive kryptonates as end-point indicators. I. Salicylic, acetylosalicylic, benzoic acids

Energy Technology Data Exchange (ETDEWEB)

Toelgyessy, J; Dillinger, P [Slovenska Vysoka Skola Technicka, Bratislava (Czechoslovakia). Chemickotechnologicka Fakulta; Harangozo, M; Jombik, J [Komenskeho Univ., Bratislava (Czechoslovakia). Farmaceuticka Fakulta

1980-01-01

A method for the determination of salicylic, acetylsalicylic and benzoic acids in officinal pharmaceutical based on radiometric titration with 0.1 mol.l/sup -1/ NaOH was developed. The end-point was detected with the aid of radioactive glass kryptonate. After the end-point, the excess titrant attacks the glass surface layers and this results in releasing /sup 85/Kr, and consequently, in decreasing the radioactivity of the kryptonate employed. The radioactive kryptonate used as an indicator was prepared by the bombardment of glass with accelerated /sup 85/Kr ions. The developed method is simple, accurate and correct.

Nutrition content of brisket point end of part Simental Ongole Crossbred meat in boiled various temperature

Science.gov (United States)

Riyanto, J.; Sudibya; Cahyadi, M.; Aji, A. P.

2018-01-01

This aim of this study was to determine the quality of nutritional contents of beef brisket point end of Simental Ongole Crossbred meat in various boiling temperatures. Simental Ongole Crossbred had been fattened for 9 months. Furthermore, they were slaughtered at slaughterhouse and brisket point end part of meat had been prepared to analyse its nutritional contents using Food Scan. These samples were then boiled at 100°C for 0 (TR), 15 (R15), and 30 (R30) minutes, respectively. The data was analysed using Randomized Complete Design (CRD) and Duncan’s multiple range test (DMRT) had been conducted to differentiate among three treatments. The results showed that boiling temperatures significantly affected moisture, and cholesterol contents of beef (P<0.05) while fat content was not significantly affected by boiling temperatures. The boiling temperature decreased beef water contents from 72.77 to 70.84%, on the other hand, the treatment increased beef protein and cholesterol contents from 20.77 to 25.14% and 47.55 to 50.45 mg/100g samples, respectively. The conclusion of this study was boiling of beef at 100°C for 15 minutes and 30 minutes decreasing water content and increasing protein and cholesterol contents of brisket point end of Simental Ongole Crossbred beef.

GFR Decline as an Alternative End Point to Kidney Failure in Clinical Trials : A Meta-analysis of Treatment Effects From 37 Randomized Trials

NARCIS (Netherlands)

Inker, Lesley A.; Lambers Heerspink, Hiddo J.; Mondal, Hasi; Schmid, Christopher H.; Tighiouart, Hocine; Noubary, Farzad; Coresh, Josef; Greene, Tom; Levey, Andrew S.

2014-01-01

Background: There is increased interest in using alternative end points for trials of kidney disease progression. The currently established end points of end-stage renal disease and doubling of serum creatinine level, equivalent to a 57% decline in estimated glomerular filtration rate (eGFR), are

Comparisons of an open-ended vs. forced-choice 'mind reading' task: implications for measuring perspective-taking and emotion recognition.

Directory of Open Access Journals (Sweden)

Tracy G Cassels

Full Text Available Perspective-taking and emotion recognition are essential for successful social development and have been the focus of developmental research for many years. Although the two abilities often overlap, they are distinct and our understanding of these abilities critically rests upon the efficacy of existing measures. Lessons from the literature differentiating recall versus recognition memory tasks led us to hypothesize that an open-ended emotion recognition measure would be less reliant on compensatory strategies and hence a more specific measure of emotion recognition abilities than a forced-choice task. To this end, we compared an open-ended version of the Reading the Mind in the Eyes Task with the original forced-choice version in two studies: 118 typically-developing 4- to 8-year-olds (Study 1 and 139 5- to 12-year-olds; 85 typically-developing and 54 with learning disorders (Study 2. We found that the open-ended version of the task was a better predictor of empathy and more reliably discriminated typically-developing children from those with learning disorders. As a whole, the results suggest that the open-ended version is a more sensitive measure of emotion recognition specifically.

Biomarkers of Host Response Predict Primary End-Point Radiological Pneumonia in Tanzanian Children with Clinical Pneumonia: A Prospective Cohort Study.

Directory of Open Access Journals (Sweden)

Laura K Erdman

Full Text Available Diagnosing pediatric pneumonia is challenging in low-resource settings. The World Health Organization (WHO has defined primary end-point radiological pneumonia for use in epidemiological and vaccine studies. However, radiography requires expertise and is often inaccessible. We hypothesized that plasma biomarkers of inflammation and endothelial activation may be useful surrogates for end-point pneumonia, and may provide insight into its biological significance.We studied children with WHO-defined clinical pneumonia (n = 155 within a prospective cohort of 1,005 consecutive febrile children presenting to Tanzanian outpatient clinics. Based on x-ray findings, participants were categorized as primary end-point pneumonia (n = 30, other infiltrates (n = 31, or normal chest x-ray (n = 94. Plasma levels of 7 host response biomarkers at presentation were measured by ELISA. Associations between biomarker levels and radiological findings were assessed by Kruskal-Wallis test and multivariable logistic regression. Biomarker ability to predict radiological findings was evaluated using receiver operating characteristic curve analysis and Classification and Regression Tree analysis.Compared to children with normal x-ray, children with end-point pneumonia had significantly higher C-reactive protein, procalcitonin and Chitinase 3-like-1, while those with other infiltrates had elevated procalcitonin and von Willebrand Factor and decreased soluble Tie-2 and endoglin. Clinical variables were not predictive of radiological findings. Classification and Regression Tree analysis generated multi-marker models with improved performance over single markers for discriminating between groups. A model based on C-reactive protein and Chitinase 3-like-1 discriminated between end-point pneumonia and non-end-point pneumonia with 93.3% sensitivity (95% confidence interval 76.5-98.8, 80.8% specificity (72.6-87.1, positive likelihood ratio 4.9 (3.4-7.1, negative likelihood ratio 0

Biomarkers of Host Response Predict Primary End-Point Radiological Pneumonia in Tanzanian Children with Clinical Pneumonia: A Prospective Cohort Study

Science.gov (United States)

Erdman, Laura K.; D’Acremont, Valérie; Hayford, Kyla; Kilowoko, Mary; Kyungu, Esther; Hongoa, Philipina; Alamo, Leonor; Streiner, David L.; Genton, Blaise; Kain, Kevin C.

2015-01-01

Background Diagnosing pediatric pneumonia is challenging in low-resource settings. The World Health Organization (WHO) has defined primary end-point radiological pneumonia for use in epidemiological and vaccine studies. However, radiography requires expertise and is often inaccessible. We hypothesized that plasma biomarkers of inflammation and endothelial activation may be useful surrogates for end-point pneumonia, and may provide insight into its biological significance. Methods We studied children with WHO-defined clinical pneumonia (n = 155) within a prospective cohort of 1,005 consecutive febrile children presenting to Tanzanian outpatient clinics. Based on x-ray findings, participants were categorized as primary end-point pneumonia (n = 30), other infiltrates (n = 31), or normal chest x-ray (n = 94). Plasma levels of 7 host response biomarkers at presentation were measured by ELISA. Associations between biomarker levels and radiological findings were assessed by Kruskal-Wallis test and multivariable logistic regression. Biomarker ability to predict radiological findings was evaluated using receiver operating characteristic curve analysis and Classification and Regression Tree analysis. Results Compared to children with normal x-ray, children with end-point pneumonia had significantly higher C-reactive protein, procalcitonin and Chitinase 3-like-1, while those with other infiltrates had elevated procalcitonin and von Willebrand Factor and decreased soluble Tie-2 and endoglin. Clinical variables were not predictive of radiological findings. Classification and Regression Tree analysis generated multi-marker models with improved performance over single markers for discriminating between groups. A model based on C-reactive protein and Chitinase 3-like-1 discriminated between end-point pneumonia and non-end-point pneumonia with 93.3% sensitivity (95% confidence interval 76.5–98.8), 80.8% specificity (72.6–87.1), positive likelihood ratio 4.9 (3.4–7

An hydrodynamic model for the calculation of oil spills trajectories

Energy Technology Data Exchange (ETDEWEB)

Paladino, Emilio Ernesto; Maliska, Clovis Raimundo [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica. Lab. de Dinamica dos Fluidos Computacionais]. E-mails: emilio@sinmec.ufsc.br; maliska@sinmec.ufsc.br

2000-07-01

The aim of this paper is to present a mathematical model and its numerical treatment to forecast oil spills trajectories in the sea. The knowledge of the trajectory followed by an oil slick spilled on the sea is of fundamental importance in the estimation of potential risks for pipeline and tankers route selection, and in combating the pollution using floating barriers, detergents, etc. In order to estimate these slicks trajectories a new model, based on the mass and momentum conservation equations is presented. The model considers the spreading in the regimes when the inertial and viscous forces counterbalance gravity and takes into account the effects of winds and water currents. The inertial forces are considered for the spreading and the displacement of the oil slick, i.e., is considered its effects on the movement of the mass center of the slick. The mass loss caused by oil evaporation is also taken into account. The numerical model is developed in generalized coordinates, making the model easily applicable to complex coastal geographies. (author)

Low dose response analysis through a cytogenetic end-point

International Nuclear Information System (INIS)

Bojtor, I.; Koeteles, G.J.

1998-01-01

The effects of low doses were studied on human lymphocytes of various individuals. The frequency of micronuclei in cytokinesis-blocked cultured lymphocytes was taken as end-point. The probability distribution of radiation-induced increment was statistically proved and identified as to be asymmetric when the blood samples had been irradiated with doses of 0.01-0.05 Gy of X-rays, similarly to that in unirradiated control population. On the contrary, at or above 1 Gy the corresponding normal curve could be accepted only reflecting an approximately symmetrical scatter of the increments about their mean value. It was found that the slope as well as the closeness of correlation of the variables considerably changed when lower and lower dose ranges had been selected. Below approximately 0.2 Gy even an unrelatedness was found betwen the absorbed dose and the increment

A new trajectory correction technique for linacs

International Nuclear Information System (INIS)

Raubenheimer, T.O.; Ruth, R.D.

1990-06-01

In this paper, we describe a new trajectory correction technique for high energy linear accelerators. Current correction techniques force the beam trajectory to follow misalignments of the Beam Position Monitors. Since the particle bunch has a finite energy spread and particles with different energies are deflected differently, this causes ''chromatic'' dilution of the transverse beam emittance. The algorithm, which we describe in this paper, reduces the chromatic error by minimizing the energy dependence of the trajectory. To test the method we compare the effectiveness of our algorithm with a standard correction technique in simulations on a design linac for a Next Linear Collider. The simulations indicate that chromatic dilution would be debilitating in a future linear collider because of the very small beam sizes required to achieve the necessary luminosity. Thus, we feel that this technique will prove essential for future linear colliders. 3 refs., 6 figs., 2 tabs

Maximum likelihood-based analysis of photon arrival trajectories in single-molecule FRET

Energy Technology Data Exchange (ETDEWEB)

Waligorska, Marta [Adam Mickiewicz University, Faculty of Chemistry, Grunwaldzka 6, 60-780 Poznan (Poland); Molski, Andrzej, E-mail: amolski@amu.edu.pl [Adam Mickiewicz University, Faculty of Chemistry, Grunwaldzka 6, 60-780 Poznan (Poland)

2012-07-25

Highlights: Black-Right-Pointing-Pointer We study model selection and parameter recovery from single-molecule FRET experiments. Black-Right-Pointing-Pointer We examine the maximum likelihood-based analysis of two-color photon trajectories. Black-Right-Pointing-Pointer The number of observed photons determines the performance of the method. Black-Right-Pointing-Pointer For long trajectories, one can extract mean dwell times that are comparable to inter-photon times. -- Abstract: When two fluorophores (donor and acceptor) are attached to an immobilized biomolecule, anti-correlated fluctuations of the donor and acceptor fluorescence caused by Foerster resonance energy transfer (FRET) report on the conformational kinetics of the molecule. Here we assess the maximum likelihood-based analysis of donor and acceptor photon arrival trajectories as a method for extracting the conformational kinetics. Using computer generated data we quantify the accuracy and precision of parameter estimates and the efficiency of the Akaike information criterion (AIC) and the Bayesian information criterion (BIC) in selecting the true kinetic model. We find that the number of observed photons is the key parameter determining parameter estimation and model selection. For long trajectories, one can extract mean dwell times that are comparable to inter-photon times.

Transition point prediction in a multicomponent lattice Boltzmann model: Forcing scheme dependencies

Science.gov (United States)

Küllmer, Knut; Krämer, Andreas; Joppich, Wolfgang; Reith, Dirk; Foysi, Holger

2018-02-01

Pseudopotential-based lattice Boltzmann models are widely used for numerical simulations of multiphase flows. In the special case of multicomponent systems, the overall dynamics are characterized by the conservation equations for mass and momentum as well as an additional advection diffusion equation for each component. In the present study, we investigate how the latter is affected by the forcing scheme, i.e., by the way the underlying interparticle forces are incorporated into the lattice Boltzmann equation. By comparing two model formulations for pure multicomponent systems, namely the standard model [X. Shan and G. D. Doolen, J. Stat. Phys. 81, 379 (1995), 10.1007/BF02179985] and the explicit forcing model [M. L. Porter et al., Phys. Rev. E 86, 036701 (2012), 10.1103/PhysRevE.86.036701], we reveal that the diffusion characteristics drastically change. We derive a generalized, potential function-dependent expression for the transition point from the miscible to the immiscible regime and demonstrate that it is shifted between the models. The theoretical predictions for both the transition point and the mutual diffusion coefficient are validated in simulations of static droplets and decaying sinusoidal concentration waves, respectively. To show the universality of our analysis, two common and one new potential function are investigated. As the shift in the diffusion characteristics directly affects the interfacial properties, we additionally show that phenomena related to the interfacial tension such as the modeling of contact angles are influenced as well.

Transition point prediction in a multicomponent lattice Boltzmann model: Forcing scheme dependencies.

Science.gov (United States)

Küllmer, Knut; Krämer, Andreas; Joppich, Wolfgang; Reith, Dirk; Foysi, Holger

2018-02-01

Pseudopotential-based lattice Boltzmann models are widely used for numerical simulations of multiphase flows. In the special case of multicomponent systems, the overall dynamics are characterized by the conservation equations for mass and momentum as well as an additional advection diffusion equation for each component. In the present study, we investigate how the latter is affected by the forcing scheme, i.e., by the way the underlying interparticle forces are incorporated into the lattice Boltzmann equation. By comparing two model formulations for pure multicomponent systems, namely the standard model [X. Shan and G. D. Doolen, J. Stat. Phys. 81, 379 (1995)JSTPBS0022-471510.1007/BF02179985] and the explicit forcing model [M. L. Porter et al., Phys. Rev. E 86, 036701 (2012)PLEEE81539-375510.1103/PhysRevE.86.036701], we reveal that the diffusion characteristics drastically change. We derive a generalized, potential function-dependent expression for the transition point from the miscible to the immiscible regime and demonstrate that it is shifted between the models. The theoretical predictions for both the transition point and the mutual diffusion coefficient are validated in simulations of static droplets and decaying sinusoidal concentration waves, respectively. To show the universality of our analysis, two common and one new potential function are investigated. As the shift in the diffusion characteristics directly affects the interfacial properties, we additionally show that phenomena related to the interfacial tension such as the modeling of contact angles are influenced as well.

Exploring the complexity of quantum control optimization trajectories.

Science.gov (United States)

Nanduri, Arun; Shir, Ofer M; Donovan, Ashley; Ho, Tak-San; Rabitz, Herschel

2015-01-07

The control of quantum system dynamics is generally performed by seeking a suitable applied field. The physical objective as a functional of the field forms the quantum control landscape, whose topology, under certain conditions, has been shown to contain no critical point suboptimal traps, thereby enabling effective searches for fields that give the global maximum of the objective. This paper addresses the structure of the landscape as a complement to topological critical point features. Recent work showed that landscape structure is highly favorable for optimization of state-to-state transition probabilities, in that gradient-based control trajectories to the global maximum value are nearly straight paths. The landscape structure is codified in the metric R ≥ 1.0, defined as the ratio of the length of the control trajectory to the Euclidean distance between the initial and optimal controls. A value of R = 1 would indicate an exactly straight trajectory to the optimal observable value. This paper extends the state-to-state transition probability results to the quantum ensemble and unitary transformation control landscapes. Again, nearly straight trajectories predominate, and we demonstrate that R can take values approaching 1.0 with high precision. However, the interplay of optimization trajectories with critical saddle submanifolds is found to influence landscape structure. A fundamental relationship necessary for perfectly straight gradient-based control trajectories is derived, wherein the gradient on the quantum control landscape must be an eigenfunction of the Hessian. This relation is an indicator of landscape structure and may provide a means to identify physical conditions when control trajectories can achieve perfect linearity. The collective favorable landscape topology and structure provide a foundation to understand why optimal quantum control can be readily achieved.

Centralized adjudication of cardiovascular end points in cardiovascular and noncardiovascular pharmacologic trials: a report from the Cardiac Safety Research Consortium.

Science.gov (United States)

Seltzer, Jonathan H; Turner, J Rick; Geiger, Mary Jane; Rosano, Giuseppe; Mahaffey, Kenneth W; White, William B; Sabol, Mary Beth; Stockbridge, Norman; Sager, Philip T

2015-02-01

This white paper provides a summary of presentations and discussions at a cardiovascular (CV) end point adjudication think tank cosponsored by the Cardiac Safety Research Committee and the US Food and Drug Administration (FDA) that was convened at the FDA's White Oak headquarters on November 6, 2013. Attention was focused on the lack of clarity concerning the need for end point adjudication in both CV and non-CV trials: there is currently an absence of widely accepted academic or industry standards and a definitive regulatory policy on how best to structure and use clinical end point committees (CECs). This meeting therefore provided a forum for leaders in the fields of CV clinical trials and CV safety to develop a foundation of initial best practice recommendations for use in future CEC charters. Attendees included representatives from pharmaceutical companies, regulatory agencies, end point adjudication specialist groups, clinical research organizations, and active, academically based adjudicators. The manuscript presents recommendations from the think tank regarding when CV end point adjudication should be considered in trials conducted by cardiologists and by noncardiologists as well as detailing key issues in the composition of a CEC and its charter. In addition, it presents several recommended best practices for the establishment and operation of CECs. The science underlying CV event adjudication is evolving, and suggestions for additional areas of research will be needed to continue to advance this science. This manuscript does not constitute regulatory guidance. Copyright © 2014 Elsevier Inc. All rights reserved.

Duality of two-point functions for confined non-relativistic quark-antiquark systems

International Nuclear Information System (INIS)

Fishbane, P.M.; Gasiorowicz, S.G.; Kaus, P.

1985-01-01

An analog to the scattering matrix describes the spectrum and high-energy behavior of confined systems. We show that for non-relativistic systems this S-matrix is identical to a two-point function which transparently describes the bound states for all angular momenta. Confined systems can thus be described in a dual fashion. This result makes it possible to study the modification of linear trajectories (originating in a long-range confining potential) due to short range forces which are unknown except for the way in which they modify the asymptotic behavior of the two point function. A type of effective range expansion is one way to calculate the energy shifts. 9 refs

Velocity-based planning of rapid elbow movements expands the control scheme of the equilibrium point hypothesis.

Science.gov (United States)

Suzuki, Masataka; Yamazaki, Yoshihiko

2005-01-01

According to the equilibrium point hypothesis of voluntary motor control, control action of muscles is not explicitly computed, but rather arises as a consequence of interaction between moving equilibrium position, current kinematics and stiffness of the joint. This approach is attractive as it obviates the need to explicitly specify the forces controlling limb movements. However, many debatable aspects of this hypothesis remain in the manner of specification of the equilibrium point trajectory and muscle activation (or its stiffness), which elicits a restoring force toward the planned equilibrium trajectory. In this study, we expanded the framework of this hypothesis by assuming that the control system uses the velocity measure as the origin of subordinate variables scaling descending commands. The velocity command is translated into muscle control inputs by second order pattern generators, which yield reciprocal command and coactivation commands, and create alternating activation of the antagonistic muscles during movement and coactivation in the post-movement phase, respectively. The velocity command is also integrated to give a position command specifying a moving equilibrium point. This model is purely kinematics-dependent, since the descending commands needed to modulate the visco-elasticity of muscles are implicitly given by simple parametric specifications of the velocity command alone. The simulated movements of fast elbow single-joint movements corresponded well with measured data performed over a wide range of movement distances, in terms of both muscle excitations and kinematics. Our proposal on a synthesis for the equilibrium point approach and velocity command, may offer some insights into the control scheme of the single-joint arm movements.

Human action recognition using trajectory-based representation

Directory of Open Access Journals (Sweden)

Haiam A. Abdul-Azim

2015-07-01

Full Text Available Recognizing human actions in video sequences has been a challenging problem in the last few years due to its real-world applications. A lot of action representation approaches have been proposed to improve the action recognition performance. Despite the popularity of local features-based approaches together with “Bag-of-Words” model for action representation, it fails to capture adequate spatial or temporal relationships. In an attempt to overcome this problem, a trajectory-based local representation approaches have been proposed to capture the temporal information. This paper introduces an improvement of trajectory-based human action recognition approaches to capture discriminative temporal relationships. In our approach, we extract trajectories by tracking the detected spatio-temporal interest points named “cuboid features” with matching its SIFT descriptors over the consecutive frames. We, also, propose a linking and exploring method to obtain efficient trajectories for motion representation in realistic conditions. Then the volumes around the trajectories’ points are described to represent human actions based on the Bag-of-Words (BOW model. Finally, a support vector machine is used to classify human actions. The effectiveness of the proposed approach was evaluated on three popular datasets (KTH, Weizmann and UCF sports. Experimental results showed that the proposed approach yields considerable performance improvement over the state-of-the-art approaches.

The effect of adherence to statin therapy on cardiovascular mortality: quantification of unmeasured bias using falsification end-points

Directory of Open Access Journals (Sweden)

Maarten J. Bijlsma

2016-04-01

Full Text Available Abstract Background To determine the clinical effectiveness of statins on cardiovascular mortality in practice, observational studies are needed. Control for confounding is essential in any observational study. Falsification end-points may be useful to determine if bias is present after adjustment has taken place. Methods We followed starters on statin therapy in the Netherlands aged 46 to 100 years over the period 1996 to 2012, from initiation of statin therapy until cardiovascular mortality or censoring. Within this group (n = 49,688, up to 16 years of follow-up, we estimated the effect of adherence to statin therapy (0 = completely non-adherent, 1 = fully adherent on ischemic heart diseases and cerebrovascular disease (ICD10-codes I20-I25 and I60-I69 as well as respiratory and endocrine disease mortality (ICD10-codes J00-J99 and E00-E90 as falsification end points, controlling for demographic factors, socio-economic factors, birth cohort, adherence to other cardiovascular medications, and diabetes using time-varying Cox regression models. Results Falsification end-points indicated that a simpler model was less biased than a model with more controls. Adherence to statins appeared to be protective against cardiovascular mortality (HR: 0.70, 95 % CI 0.61 to 0.81. Conclusions Falsification end-points helped detect overadjustment bias or bias due to competing risks, and thereby proved to be a useful technique in such a complex setting.

Estimated GFR Decline as a Surrogate End Point for Kidney Failure : A Post Hoc Analysis From the Reduction of End Points in Non-Insulin-Dependent Diabetes With the Angiotensin II Antagonist Losartan (RENAAL) Study and Irbesartan Diabetic Nephropathy Trial (IDNT)

NARCIS (Netherlands)

Lambers Heerspink, Hiddo; Weldegiorgis, Misghina; Inker, Lesley A.; Gansevoort, Ron; Parving, Hans-Henrik; Dwyer, Jamie P.; Mondal, Hasi; Coresh, Josef; Greene, Tom; Levey, Andrew S.; de Zeeuw, Dick

Background: A doubling of serum creatinine value, corresponding to a 57% decline in estimated glomerular filtration rate (eGFR), is used frequently as a component of a composite kidney end point in clinical trials in type 2 diabetes. The aim of this study was to determine whether alternative end

A Segment-Based Trajectory Similarity Measure in the Urban Transportation Systems.

Science.gov (United States)

Mao, Yingchi; Zhong, Haishi; Xiao, Xianjian; Li, Xiaofang

2017-03-06

With the rapid spread of built-in GPS handheld smart devices, the trajectory data from GPS sensors has grown explosively. Trajectory data has spatio-temporal characteristics and rich information. Using trajectory data processing techniques can mine the patterns of human activities and the moving patterns of vehicles in the intelligent transportation systems. A trajectory similarity measure is one of the most important issues in trajectory data mining (clustering, classification, frequent pattern mining, etc.). Unfortunately, the main similarity measure algorithms with the trajectory data have been found to be inaccurate, highly sensitive of sampling methods, and have low robustness for the noise data. To solve the above problems, three distances and their corresponding computation methods are proposed in this paper. The point-segment distance can decrease the sensitivity of the point sampling methods. The prediction distance optimizes the temporal distance with the features of trajectory data. The segment-segment distance introduces the trajectory shape factor into the similarity measurement to improve the accuracy. The three kinds of distance are integrated with the traditional dynamic time warping algorithm (DTW) algorithm to propose a new segment-based dynamic time warping algorithm (SDTW). The experimental results show that the SDTW algorithm can exhibit about 57%, 86%, and 31% better accuracy than the longest common subsequence algorithm (LCSS), and edit distance on real sequence algorithm (EDR) , and DTW, respectively, and that the sensitivity to the noise data is lower than that those algorithms.

Same Program, Distinctive Development: Exploring the Biliteracy Trajectories of Two Dual Language Schools

Science.gov (United States)

Babino, Alexandra

2017-01-01

Using a mixed methods comparative case study, the researcher explored the dual language contexts at each school before examining the second- through fifth-grade Spanish and English reading biliteracy trajectories. While both campuses' students experienced positive trajectories toward biliteracy by the end of fifth grade, each campus was…

HOTSPOTS DETECTION FROM TRAJECTORY DATA BASED ON SPATIOTEMPORAL DATA FIELD CLUSTERING

Directory of Open Access Journals (Sweden)

K. Qin

2017-09-01

Full Text Available City hotspots refer to the areas where residents visit frequently, and large traffic flow exist, which reflect the people travel patterns and distribution of urban function area. Taxi trajectory data contain abundant information about urban functions and citizen activities, and extracting interesting city hotspots from them can be of importance in urban planning, traffic command, public travel services etc. To detect city hotspots and discover a variety of changing patterns among them, we introduce a data field-based cluster analysis technique to the pick-up and drop-off points of taxi trajectory data and improve the method by introducing the time weight, which has been normalized to estimate the potential value in data field. Thus, in the light of the new potential function in data field, short distance and short time difference play a powerful role. So the region full of trajectory points, which is regarded as hotspots area, has a higher potential value, while the region with thin trajectory points has a lower potential value. The taxi trajectory data of Wuhan city in China on May 1, 6 and 9, 2015, are taken as the experimental data. From the result, we find the sustaining hotspots area and inconstant hotspots area in Wuhan city based on the spatiotemporal data field method. Further study will focus on optimizing parameter and the interaction among hotspots area.

ASTP (SA-210) Launch vehicle operational flight trajectory. Part 3: Final documentation

Science.gov (United States)

Carter, A. B.; Klug, G. W.; Williams, N. W.

1975-01-01

Trajectory data are presented for a nominal and two launch window trajectory simulations. These trajectories are designed to insert a manned Apollo spacecraft into a 150/167 km. (81/90 n. mi.) earth orbit inclined at 51.78 degrees for rendezvous with a Soyuz spacecraft, which will be orbiting at approximately 225 km. (121.5 n. mi.). The launch window allocation defined for this launch is 500 pounds of S-IVB stage propellant. The launch window opening trajectory simulation depicts the earliest launch time deviation from a planar flight launch which conforms to this constraint. The launch window closing trajectory simulation was developed for the more stringent Air Force Eastern Test Range (AFETR) flight azimuth restriction of 37.4 degrees east-of-north. These trajectories enclose a 12.09 minute launch window, pertinent features of which are provided in a tabulation. Planar flight data are included for mid-window reference.

Optimization of Low-Thrust Spiral Trajectories by Collocation

Science.gov (United States)

Falck, Robert D.; Dankanich, John W.

2012-01-01

As NASA examines potential missions in the post space shuttle era, there has been a renewed interest in low-thrust electric propulsion for both crewed and uncrewed missions. While much progress has been made in the field of software for the optimization of low-thrust trajectories, many of the tools utilize higher-fidelity methods which, while excellent, result in extremely high run-times and poor convergence when dealing with planetocentric spiraling trajectories deep within a gravity well. Conversely, faster tools like SEPSPOT provide a reasonable solution but typically fail to account for other forces such as third-body gravitation, aerodynamic drag, solar radiation pressure. SEPSPOT is further constrained by its solution method, which may require a very good guess to yield a converged optimal solution. Here the authors have developed an approach using collocation intended to provide solution times comparable to those given by SEPSPOT while allowing for greater robustness and extensible force models.

Development of a Whole-Body Haptic Sensor with Multiple Supporting Points and Its Application to a Manipulator

Science.gov (United States)

Hanyu, Ryosuke; Tsuji, Toshiaki

This paper proposes a whole-body haptic sensing system that has multiple supporting points between the body frame and the end-effector. The system consists of an end-effector and multiple force sensors. Using this mechanism, the position of a contact force on the surface can be calculated without any sensor array. A haptic sensing system with a single supporting point structure has previously been developed by the present authors. However, the system has drawbacks such as low stiffness and low strength. Therefore, in this study, a mechanism with multiple supporting points was proposed and its performance was verified. In this paper, the basic concept of the mechanism is first introduced. Next, an evaluation of the proposed method, performed by conducting some experiments, is presented.

Adaptive Square-Shaped Trajectory-Based Service Location Protocol in Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Hwa-Jung Lim

2010-04-01

Full Text Available In this paper we propose an adaptive square-shaped trajectory (ASST-based service location method to ensure load scalability in wireless sensor networks. This first establishes a square-shaped trajectory over the nodes that surround a target point computed by the hash function and any user can access it, using the hash. Both the width and the size of the trajectory are dynamically adjustable, depending on the number of queries made to the service information on the trajectory. The number of sensor nodes on the trajectory varies in proportion to the changing trajectory shape, allowing high loads to be distributed around the hot spot area.

Controlling particle trajectories using oscillating microbubbles

Science.gov (United States)

Jalikop, Shreyas; Wang, Cheng; Hilgenfeldt, Sascha

2010-11-01

In many applications of microfluidics and biotechnology, such as cytometry and drug delivery, it is vital to manipulate the trajectories of microparticles such as vesicles or cells. On this small scale, inertial or gravitational effects are often too weak to exploit. We propose a mechanism to selectively trap and direct particles based on their size in creeping transport flows (Re1). We employ Rayleigh-Nyborg-Westervelt (RNW) streaming generated by an oscillating microbubble, which in turn generates a streaming flow component around the mobile particles. The result is an attractive interaction that draws the particle closer to the bubble. The impenetrability of the bubble interface destroys time-reversal symmetry and forces the particles onto either narrow trajectory bundles or well-defined closed trajectories, where they are trapped. The effect is dependent on particle size and thus allows for the passive focusing and sorting of selected sizes, on scales much smaller than the geometry of the microfluidic device. The device could eliminate the need for complicated microchannel designs with external magnetic or electric fields in applications such as particle focusing and size-based sorting.

New drugs and patient-centred end-points in old age: setting the wheels in motion.

Science.gov (United States)

Mangoni, Arduino A; Pilotto, Alberto

2016-01-01

Older patients with various degrees of frailty and disability, a key population target of pharmacological interventions in acute and chronic disease states, are virtually neglected in pre-marketing studies assessing the efficacy and safety of investigational drugs. Moreover, aggressively pursuing established therapeutic targets in old age, e.g. blood pressure, serum glucose or cholesterol concentrations, is not necessarily associated with the beneficial effects, and the acceptable safety, reported in younger patient cohorts. Measures of self-reported health and functional status might represent additional, more meaningful, therapeutic end-points in the older population, particularly in patients with significant frailty and relatively short life expectancy, e.g. in the presence of cancer and/or neurodegenerative disease conditions. Strategies enhancing early knowledge about key pharmacological characteristics of investigational drugs targeting older adults are discussed, together with the rationale for incorporating non-traditional, patient-centred, end-points in this ever-increasing group.

Integral force feedback control with input shaping: Application to piezo-based scanning systems in ECDLs

Science.gov (United States)

Zhang, Meng; Liu, Zhigang; Zhu, Yu; Bu, Mingfan; Hong, Jun

2017-07-01

In this paper, a hybrid control system is developed by integrating the closed-loop force feedback and input shaping method to overcome the problem of the hysteresis and dynamic behavior in piezo-based scanning systems and increase the scanning speed of tunable external cavity diode lasers. The flexible hinge and piezoelectric actuators are analyzed, and a dynamic model of the scanning systems is established. A force sensor and an integral controller are utilized in integral force feedback (IFF) to directly augment the damping of the piezoelectric scanning systems. Hysteresis has been effectively eliminated, but the mechanical resonance is still evident. Noticeable residual vibration occurred after the inflection points and then gradually disappeared. For the further control of mechanical resonance, based on the theory of minimum-acceleration trajectory planning, the time-domain input shaping method was developed. The turning sections of a scanning trajectory are replaced by smooth curves, while the linear sections are retained. The IFF method is combined with the input shaping method to control the non-linearity and mechanical resonance in high-speed piezo-based scanning systems. Experiments are conducted, and the results demonstrate the effectiveness of the proposed control approach.

Integral force feedback control with input shaping: Application to piezo-based scanning systems in ECDLs.

Science.gov (United States)

Zhang, Meng; Liu, Zhigang; Zhu, Yu; Bu, Mingfan; Hong, Jun

2017-07-01

In this paper, a hybrid control system is developed by integrating the closed-loop force feedback and input shaping method to overcome the problem of the hysteresis and dynamic behavior in piezo-based scanning systems and increase the scanning speed of tunable external cavity diode lasers. The flexible hinge and piezoelectric actuators are analyzed, and a dynamic model of the scanning systems is established. A force sensor and an integral controller are utilized in integral force feedback (IFF) to directly augment the damping of the piezoelectric scanning systems. Hysteresis has been effectively eliminated, but the mechanical resonance is still evident. Noticeable residual vibration occurred after the inflection points and then gradually disappeared. For the further control of mechanical resonance, based on the theory of minimum-acceleration trajectory planning, the time-domain input shaping method was developed. The turning sections of a scanning trajectory are replaced by smooth curves, while the linear sections are retained. The IFF method is combined with the input shaping method to control the non-linearity and mechanical resonance in high-speed piezo-based scanning systems. Experiments are conducted, and the results demonstrate the effectiveness of the proposed control approach.

The end point of the first-order phase transition of the SU(2) gauge-Higgs model on a four-dimensional isotropic lattice

International Nuclear Information System (INIS)

Aoki, Y.; Csikor, F.; Fodor, Z.; Ukawa, A.

1999-01-01

We report results of a study of the end point of the electroweak phase transition of the SU(2) gauge-Higgs model defined on a four-dimensional isotropic lattice with N t = 2. Finite-size scaling study of Lee-Yang zeros yields λ c = 0.00116(16) for the end point. Combined with a zero-temperature measurement of Higgs and W boson masses, this leads to M H,c = 68.2 ± 6.6 GeV for the critical Higgs boson mass. An independent analysis of Binder cumulant gives a consistent value λ c = 0.00102(3) for the end point

Guidelines for the definition of time-to-event end points in renal cell cancer clinical trials: results of the DATECAN project†.

Science.gov (United States)

Kramar, A; Negrier, S; Sylvester, R; Joniau, S; Mulders, P; Powles, T; Bex, A; Bonnetain, F; Bossi, A; Bracarda, S; Bukowski, R; Catto, J; Choueiri, T K; Crabb, S; Eisen, T; El Demery, M; Fitzpatrick, J; Flamand, V; Goebell, P J; Gravis, G; Houédé, N; Jacqmin, D; Kaplan, R; Malavaud, B; Massard, C; Melichar, B; Mourey, L; Nathan, P; Pasquier, D; Porta, C; Pouessel, D; Quinn, D; Ravaud, A; Rolland, F; Schmidinger, M; Tombal, B; Tosi, D; Vauleon, E; Volpe, A; Wolter, P; Escudier, B; Filleron, T

2015-12-01

In clinical trials, the use of intermediate time-to-event end points (TEEs) is increasingly common, yet their choice and definitions are not standardized. This limits the usefulness for comparing treatment effects between studies. The aim of the DATECAN Kidney project is to clarify and recommend definitions of TEE in renal cell cancer (RCC) through a formal consensus method for end point definitions. A formal modified Delphi method was used for establishing consensus. From a 2006-2009 literature review, the Steering Committee (SC) selected 9 TEE and 15 events in the nonmetastatic (NM) and metastatic/advanced (MA) RCC disease settings. Events were scored on the range of 1 (totally disagree to include) to 9 (totally agree to include) in the definition of each end point. Rating Committee (RC) experts were contacted for the scoring rounds. From these results, final recommendations were established for selecting pertinent end points and the associated events. Thirty-four experts scored 121 events for 9 end points. Consensus was reached for 31%, 43% and 85% events during the first, second and third rounds, respectively. The expert recommend the use of three and two endpoints in NM and MA setting, respectively. In the NM setting: disease-free survival (contralateral RCC, appearance of metastases, local or regional recurrence, death from RCC or protocol treatment), metastasis-free survival (appearance of metastases, regional recurrence, death from RCC); and local-regional-free survival (local or regional recurrence, death from RCC). In the MA setting: kidney cancer-specific survival (death from RCC or protocol treatment) and progression-free survival (death from RCC, local, regional, or metastatic progression). The consensus method revealed that intermediate end points have not been well defined, because all of the selected end points had at least one event definition for which no consensus was obtained. These clarified definitions of TEE should become standard practice in

Trajectory learning from human demonstrations via manifold mapping

CSIR Research Space (South Africa)

Hiratsuka, M

2016-10-01

Full Text Available constantly, and to this end we present an approach for users to be able to easily teach a skill to a robot with any body configuration. Our proposed method requires a motion trajectory obtained from human demonstrations via a Kinect sensor, which...

Topology of the drift trajectories of charged particles and heat transfer in tokamaks

International Nuclear Information System (INIS)

Gott, Yu.V.; Yurchenko, Eh.I.

1999-01-01

Equation enabling to analyze both analytically and numerically the topology of particle drift trajectories both at the periphery and in the central range of the plasma filament was obtained for axial-symmetric tokamaks within the special space associated with the invariants of particle motion. The real topology of particle trajectories especially within the central range of the plasma filament was shown to be more complex in contrast to the topology of trajectories studied in terms of neoclassical theory. For example, there are trajectories of locked particles bypassing the magnetic axis and having one or two points of rotation in every half plane or having no such points at all. Approximation formula for ion heat transfer factor in the banana regime holding true for the whole range occupied with plasma was obtained [ru

Dynamic trajectory-based couch motion for improvement of radiation therapy trajectories in cranial SRT

Energy Technology Data Exchange (ETDEWEB)

MacDonald, R. Lee [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia B3H 4R2 (Canada); Thomas, Christopher G., E-mail: Chris.Thomas@cdha.nshealth.ca [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia B3H 4R2 (Canada); Department of Medical Physics, Nova Scotia Cancer Centre, Queen Elizabeth II Health Sciences Centre, Halifax, Nova Scotia B3H 1V7 (Canada); Department of Radiation Oncology, Dalhousie University, Halifax, Nova Scotia B3H 4R2 (Canada); Department of Radiology, Dalhousie University, Halifax, Nova Scotia B3H 4R2 (Canada)

2015-05-15

Purpose: To investigate potential improvement in external beam stereotactic radiation therapy plan quality for cranial cases using an optimized dynamic gantry and patient support couch motion trajectory, which could minimize exposure to sensitive healthy tissue. Methods: Anonymized patient anatomy and treatment plans of cranial cancer patients were used to quantify the geometric overlap between planning target volumes and organs-at-risk (OARs) based on their two-dimensional projection from source to a plane at isocenter as a function of gantry and couch angle. Published dose constraints were then used as weighting factors for the OARs to generate a map of couch-gantry coordinate space, indicating degree of overlap at each point in space. A couch-gantry collision space was generated by direct measurement on a linear accelerator and couch using an anthropomorphic solid-water phantom. A dynamic, fully customizable algorithm was written to generate a navigable ideal trajectory for the patient specific couch-gantry space. The advanced algorithm can be used to balance the implementation of absolute minimum values of overlap with the clinical practicality of large-scale couch motion and delivery time. Optimized cranial cancer treatment trajectories were compared to conventional treatment trajectories. Results: Comparison of optimized treatment trajectories with conventional treatment trajectories indicated an average decrease in mean dose to the OARs of 19% and an average decrease in maximum dose to the OARs of 12%. Degradation was seen for homogeneity index (6.14% ± 0.67%–5.48% ± 0.76%) and conformation number (0.82 ± 0.02–0.79 ± 0.02), but neither was statistically significant. Removal of OAR constraints from volumetric modulated arc therapy optimization reveals that reduction in dose to OARs is almost exclusively due to the optimized trajectory and not the OAR constraints. Conclusions: The authors’ study indicated that simultaneous couch and gantry motion

Dynamic trajectory-based couch motion for improvement of radiation therapy trajectories in cranial SRT

International Nuclear Information System (INIS)

MacDonald, R. Lee; Thomas, Christopher G.

2015-01-01

Purpose: To investigate potential improvement in external beam stereotactic radiation therapy plan quality for cranial cases using an optimized dynamic gantry and patient support couch motion trajectory, which could minimize exposure to sensitive healthy tissue. Methods: Anonymized patient anatomy and treatment plans of cranial cancer patients were used to quantify the geometric overlap between planning target volumes and organs-at-risk (OARs) based on their two-dimensional projection from source to a plane at isocenter as a function of gantry and couch angle. Published dose constraints were then used as weighting factors for the OARs to generate a map of couch-gantry coordinate space, indicating degree of overlap at each point in space. A couch-gantry collision space was generated by direct measurement on a linear accelerator and couch using an anthropomorphic solid-water phantom. A dynamic, fully customizable algorithm was written to generate a navigable ideal trajectory for the patient specific couch-gantry space. The advanced algorithm can be used to balance the implementation of absolute minimum values of overlap with the clinical practicality of large-scale couch motion and delivery time. Optimized cranial cancer treatment trajectories were compared to conventional treatment trajectories. Results: Comparison of optimized treatment trajectories with conventional treatment trajectories indicated an average decrease in mean dose to the OARs of 19% and an average decrease in maximum dose to the OARs of 12%. Degradation was seen for homogeneity index (6.14% ± 0.67%–5.48% ± 0.76%) and conformation number (0.82 ± 0.02–0.79 ± 0.02), but neither was statistically significant. Removal of OAR constraints from volumetric modulated arc therapy optimization reveals that reduction in dose to OARs is almost exclusively due to the optimized trajectory and not the OAR constraints. Conclusions: The authors’ study indicated that simultaneous couch and gantry motion

Puff-trajectory modelling for long-duration releases

International Nuclear Information System (INIS)

Underwood, B.Y.

1988-01-01

This investigation considers some aspects of the interpretation and application of the puff-trajectory technique which is increasingly being considered for use in accident consequence assessment. It firsthigh lights the problems of applying the straight-line Gaussian model to releases of many hours duration and the drawbacks of using the ad hoc technique of multiple straight-line plumes, thereby pointing to the advantages of allowing curved trajectories. A number of fundamental questions are asked about the conventional puff-trajectory approach such as: what is the justification for using ensemble-average spread parameters (σ values) in constructing particular realizations of the concentration field and to what sampling time should these σ values correspond. These questions are answered in the present work by returning to basics: an interpretation of the puff-trajectory method is developed which establishes a correspondence between the omission of wind-field fluctuations with period below a given value in the generation of trajectories and the achievable spatial resolution of the estimates of time-integrated concentration. In application to accident consequence assessment, this focusses attention on what spatial resolution is necessary for particular consequence types or is implicit in the computational discretization employed

Rare behavior of growth processes via umbrella sampling of trajectories

Science.gov (United States)

Klymko, Katherine; Geissler, Phillip L.; Garrahan, Juan P.; Whitelam, Stephen

2018-03-01

We compute probability distributions of trajectory observables for reversible and irreversible growth processes. These results reveal a correspondence between reversible and irreversible processes, at particular points in parameter space, in terms of their typical and atypical trajectories. Thus key features of growth processes can be insensitive to the precise form of the rate constants used to generate them, recalling the insensitivity to microscopic details of certain equilibrium behavior. We obtained these results using a sampling method, inspired by the "s -ensemble" large-deviation formalism, that amounts to umbrella sampling in trajectory space. The method is a simple variant of existing approaches, and applies to ensembles of trajectories controlled by the total number of events. It can be used to determine large-deviation rate functions for trajectory observables in or out of equilibrium.

Nambu-Goto string with the Gauss-Bonnet term and point-like masses at the ends

Science.gov (United States)

Hadasz, Leszek; Róg, Tomasz

1996-02-01

We investigate classical dynamics of the Nambu-Goto string with Gauss-Bonnet term in the action and point-like masses at the ends in the context of effective QCD string. The configuration of rigidly rotating string is studied and its application to phenomenological description of meson spectroscopy is discussed.

Growth Trajectories of Exercise Self-Efficacy in Older Adults: Influence of Measures and Initial Status

Science.gov (United States)

McAuley, Edward; Mailey, Emily L.; Mullen, Sean P.; Szabo, Amanda N.; Wójcicki, Thomas R.; White, Siobhan M.; Gothe, Neha; Olson, Erin A.; Kramer, Arthur F.

2012-01-01

Objective This study examines differential trajectories of exercise-related self-efficacy beliefs across a 12-month randomized controlled exercise trial. Methods Previously inactive older adults (N = 144; M age = 66.5) were randomly assigned to one of two exercise conditions (walking, flexibility-toning-balance) and completed measures of barriers self-efficacy (BARSE), exercise self-efficacy (EXSE), and self-efficacy for walking (SEW) across a 12-month period. Changes in efficacy were examined according to efficacy type and inter-individual differences. Latent growth curve modeling was employed to (a) examine average levels and change in each type of efficacy for the collapsed sample and by intervention condition, and (b) explore subpopulations (i.e., latent classes) within the sample that differ in their baseline efficacy and trajectory. Results Analyses revealed two negative trends in BARSE and EXSE at predicted transition points, in addition to a positive linear trend in SEW. Two subgroups with unique baseline efficacy and trajectory profiles were also identified. Conclusions These results shed new light on the relationship between exercise and self-efficacy in older adults, and highlight the need for strategies for increasing and maintaining efficacy within interventions, namely targeting participants who start with a disadvantage (lower efficacy) and integrating efficacy-boosting strategies for all participants prior to program end. PMID:21038962

Application of the nudged elastic band method to the point-to-point radio wave ray tracing in IRI modeled ionosphere

Science.gov (United States)

Nosikov, I. A.; Klimenko, M. V.; Bessarab, P. F.; Zhbankov, G. A.

2017-07-01

Point-to-point ray tracing is an important problem in many fields of science. While direct variational methods where some trajectory is transformed to an optimal one are routinely used in calculations of pathways of seismic waves, chemical reactions, diffusion processes, etc., this approach is not widely known in ionospheric point-to-point ray tracing. We apply the Nudged Elastic Band (NEB) method to a radio wave propagation problem. In the NEB method, a chain of points which gives a discrete representation of the radio wave ray is adjusted iteratively to an optimal configuration satisfying the Fermat's principle, while the endpoints of the trajectory are kept fixed according to the boundary conditions. Transverse displacements define the radio ray trajectory, while springs between the points control their distribution along the ray. The method is applied to a study of point-to-point ionospheric ray tracing, where the propagation medium is obtained with the International Reference Ionosphere model taking into account traveling ionospheric disturbances. A 2-dimensional representation of the optical path functional is developed and used to gain insight into the fundamental difference between high and low rays. We conclude that high and low rays are minima and saddle points of the optical path functional, respectively.

Augmenting Parametric Optimal Ascent Trajectory Modeling with Graph Theory

Science.gov (United States)

Dees, Patrick D.; Zwack, Matthew R.; Edwards, Stephen; Steffens, Michael

2016-01-01

It has been well documented that decisions made in the early stages of Conceptual and Pre-Conceptual design commit up to 80% of total Life-Cycle Cost (LCC) while engineers know the least about the product they are designing [1]. Once within Preliminary and Detailed design however, making changes to the design becomes far more difficult to enact in both cost and schedule. Primarily this has been due to a lack of detailed data usually uncovered later during the Preliminary and Detailed design phases. In our current budget-constrained environment, making decisions within Conceptual and Pre-Conceptual design which minimize LCC while meeting requirements is paramount to a program's success. Within the arena of launch vehicle design, optimizing the ascent trajectory is critical for minimizing the costs present within such concerns as propellant, aerodynamic, aeroheating, and acceleration loads while meeting requirements such as payload delivered to a desired orbit. In order to optimize the vehicle design its constraints and requirements must be known, however as the design cycle proceeds it is all but inevitable that the conditions will change. Upon that change, the previously optimized trajectory may no longer be optimal, or meet design requirements. The current paradigm for adjusting to these updates is generating point solutions for every change in the design's requirements [2]. This can be a tedious, time-consuming task as changes in virtually any piece of a launch vehicle's design can have a disproportionately large effect on the ascent trajectory, as the solution space of the trajectory optimization problem is both non-linear and multimodal [3]. In addition, an industry standard tool, Program to Optimize Simulated Trajectories (POST), requires an expert analyst to produce simulated trajectories that are feasible and optimal [4]. In a previous publication the authors presented a method for combatting these challenges [5]. In order to bring more detailed information

Force-sensed interface for control and training space robot

Science.gov (United States)

Moiseev, O. S.; Sarsadskikh, A. S.; Povalyaev, N. D.; Gorbunov, V. I.; Kulakov, F. M.; Vasilev, V. V.

2018-05-01

A method of positional and force-torque control of robots is proposed. Prototypes of the system and the master handle have been created. Algorithm of bias estimation and gravity compensation for force-torque sensor and force-torque trajectory correction are described.

Effective Online Group Discovery in Trajectory Databases

DEFF Research Database (Denmark)

Li, Xiaohui; Ceikute, Vaida; Jensen, Christian S.

2013-01-01

GPS-enabled devices are pervasive nowadays. Finding movement patterns in trajectory data stream is gaining in importance. We propose a group discovery framework that aims to efficiently support the online discovery of moving objects that travel together. The framework adopts a sampling-independen......GPS-enabled devices are pervasive nowadays. Finding movement patterns in trajectory data stream is gaining in importance. We propose a group discovery framework that aims to efficiently support the online discovery of moving objects that travel together. The framework adopts a sampling......-independent approach that makes no assumptions about when positions are sampled, gives no special importance to sampling points, and naturally supports the use of approximate trajectories. The framework's algorithms exploit state-of-the-art, density-based clustering (DBScan) to identify groups. The groups are scored...

An industrial robot singular trajectories planning based on graphs and neural networks

Science.gov (United States)

Łęgowski, Adrian; Niezabitowski, Michał

2016-06-01

Singular trajectories are rarely used because of issues during realization. A method of planning trajectories for given set of points in task space with use of graphs and neural networks is presented. In every desired point the inverse kinematics problem is solved in order to derive all possible solutions. A graph of solutions is made. The shortest path is determined to define required nodes in joint space. Neural networks are used to define the path between these nodes.

Singular trajectories: space-time domain topology of developing speckle fields

Science.gov (United States)

Vasil'ev, Vasiliy; Soskin, Marat S.

2010-02-01

It is shown the space-time dynamics of optical singularities is fully described by singularities trajectories in space-time domain, or evolution of transverse coordinates(x, y) in some fixed plane z0. The dynamics of generic developing speckle fields was realized experimentally by laser induced scattering in LiNbO3:Fe photorefractive crystal. The space-time trajectories of singularities can be divided topologically on two classes with essentially different scenario and duration. Some of them (direct topological reactions) consist from nucleation of singularities pair at some (x, y, z0, t) point, their movement and annihilation. They possess form of closed loops with relatively short time of existence. Another much more probable class of trajectories are chain topological reactions. Each of them consists from sequence of links, i.e. of singularities nucleation in various points (xi yi, ti) and following annihilation of both singularities in other space-time points with alien singularities of opposite topological indices. Their topology and properties are established. Chain topological reactions can stop on the borders of a developing speckle field or go to infinity. Examples of measured both types of topological reactions for optical vortices (polarization C points) in scalar (elliptically polarized) natural developing speckle fields are presented.

Equilibrium-point control hypothesis examined by measured arm stiffness during multijoint movement.

Science.gov (United States)

Gomi, H; Kawato

1996-04-05

For the last 20 years, it has been hypothesized that well-coordinated, multijoint movements are executed without complex computation by the brain, with the use of springlike muscle properties and peripheral neural feedback loops. However, it has been technically and conceptually difficult to examine this "equilibrium-point control" hypothesis directly in physiological or behavioral experiments. A high-performance manipulandum was developed and used here to measure human arm stiffness, the magnitude of which during multijoint movement is important for this hypothesis. Here, the equilibrium-point trajectory was estimated from the measured stiffness, the actual trajectory, and the generated torque. Its velocity profile differed from that of the actual trajectory. These results argue against the hypothesis that the brain sends as a motor command only an equilibrium-point trajectory similar to the actual trajectory.

Impacts of Deflection Nose on Ballistic Trajectory Control Law

Directory of Open Access Journals (Sweden)

Bo Zhang

2014-01-01

Full Text Available The deflection of projectile nose is aimed at changing the motion of the projectile in flight with the theory of motion control and changing the exterior ballistics so as to change its range and increase its accuracy. The law of external ballistics with the deflectable nose is considered as the basis of the design of a flight control system and an important part in the process of projectile development. Based on the existing rigid external ballistic model, this paper establishes an external ballistic calculation model for deflectable nose projectile and further establishes the solving programs accordingly. Different angle of attack, velocity, coefficients of lift, resistance, and moment under the deflection can be obtained in this paper based on the previous experiments and emulation researches. In the end, the author pointed out the laws on the impaction of external ballistic trajectory by the deflection of nose of the missile.

AN INVESTIGATION INTO THE EFFECT OF PHOTOVOLTAIC MODULE ELECTRIC PROPERTIES ON MAXIMUM POWER POINT TRAJECTORY WITH THE AIM OF ITS ALIGNMENT WITH ELECTROLYZER U-I CHARACTERISTIC

Directory of Open Access Journals (Sweden)

Mihajlo Firak

2010-01-01

Full Text Available In order to combine a photovoltaic module and an electrolyzer to produce hydrogen from water, an intermediate DC/DC converter can be used to adapt output power features of the module to input power features of the electrolyzer. This can also be done without using electronics, which results in saving as much as 700 USD/kW, as previous investigation has shown. A more sophisticated investigation should be carried out with the aim of improving high system efficiency, resulting in matching the photovoltaic module maximum power point trajectory (the maximum power point path in the U-I plane as a result of solar irradiance change to the operating characteristic of the electrolyzer. This paper presents an analysis of the influences of photovoltaic module electric properties, such as series and parallel resistance and non-ideality factor, on the maximum power point trajectory at different levels of solar irradiance. The possibility of various inclinations (right - vertical - left in relation to an arbitrary chosen operating characteristic of the electrolyzer is also demonstrated. Simulated results are obtained by using Matlab/Simulink simulations of the well known one-diode model. Simulations have been confirmed with experiments on a real photovoltaic module where solar irradiance, solar cell temperature, electric current, and voltage in the circuit with variable ohmic resistance have been measured.

Trajectories of depressive symptoms among high risk African-American adolescents.

Science.gov (United States)

Repetto, Paula B; Caldwell, Cleopatra H; Zimmerman, Marc A

2004-12-01

To examine the trajectories of depressive symptoms among African-American youth and the psychosocial factors associated with these trajectories. The sample included 579 African-American adolescents who were at risk of dropping out of school, interviewed annually starting from ninth grade for 4 years. The measures included depressive symptoms, anxiety symptoms, self-esteem, stress, and active coping; all self-reported. We used cluster analysis to develop longitudinal trajectories of depression in our sample. Four different trajectories of depressive symptoms were found that represented the changes in depressive symptoms among the participants. These trajectories are: consistently high (15.9%), consistently low (21.1%), decreasing (41.8%), and increasing (21.2%) depressive symptoms. The results from the comparisons of the trajectories indicated that adolescents who presented consistently high levels of depressive symptoms were more likely to be female, reported more anxiety symptoms, lower self-esteem, higher stress, and lower grade point average (GPA) compared with adolescent members of the other trajectories. Depressive symptoms may be manifested in different ways according to the patterns of change. Different correlates are associated with these trajectories of depressive symptoms and provide insights about the antecedents and consequences of the patterns of change in depressive symptoms.

Defining the end-point of mastication: A conceptual model.

Science.gov (United States)

Gray-Stuart, Eli M; Jones, Jim R; Bronlund, John E

2017-10-01

properties define the end-point texture and enduring sensory perception of the food. © 2017 Wiley Periodicals, Inc.

Indexing Moving Points

DEFF Research Database (Denmark)

Agarwal, Pankaj K.; Arge, Lars Allan; Erickson, Jeff

2003-01-01

We propose three indexing schemes for storing a set S of N points in the plane, each moving along a linear trajectory, so that any query of the following form can be answered quickly: Given a rectangle R and a real value t, report all K points of S that lie inside R at time t. We first present an...

Kinematic geometry of a line trajectory in spatial motion

Energy Technology Data Exchange (ETDEWEB)

Al-Ghefari, Reem A. [King Abdulaziz University, Jeddah (Saudi Arabia); Abdel-Baky, Rashad A. [University of Assiut, Assiu (Egypt)

2015-09-15

This paper derives the equations of line-trajectory in spatial motion by means of the E. Study dual-line coordinates. A special emphasis goes to the second-order motion properties for deriving a new proof of the Disteli formulae. As an application concise explicit expressions of the inflection line congruence are directly obtained. Also, a new metric is developed and used to investigate the geometrical properties and kinematics of line trajectory as well as Disteli axis. Finally, a theoretical expressions of point trajectories with special values of velocity and acceleration, which can be considered as a form Euler-Savary equation, for spherical and planar motions are discussed.

Dysglycemia and Index60 as Prediagnostic End Points for Type 1 Diabetes Prevention Trials.

Science.gov (United States)

Nathan, Brandon M; Boulware, David; Geyer, Susan; Atkinson, Mark A; Colman, Peter; Goland, Robin; Russell, William; Wentworth, John M; Wilson, Darrell M; Evans-Molina, Carmella; Wherrett, Diane; Skyler, Jay S; Moran, Antoinette; Sosenko, Jay M

2017-11-01

We assessed dysglycemia and a T1D Diagnostic Index60 (Index60) ≥1.00 (on the basis of fasting C-peptide, 60-min glucose, and 60-min C-peptide levels) as prediagnostic end points for type 1 diabetes among Type 1 Diabetes TrialNet Pathway to Prevention Study participants. Two cohorts were analyzed: 1 ) baseline normoglycemic oral glucose tolerance tests (OGTTs) with an incident dysglycemic OGTT and 2 ) baseline Index60 <1.00 OGTTs with an incident Index60 ≥1.00 OGTT. Incident dysglycemic OGTTs were divided into those with (DYS/IND+) and without (DYS/IND-) concomitant Index60 ≥1.00. Incident Index60 ≥1.00 OGTTs were divided into those with (IND/DYS+) and without (IND/DYS-) concomitant dysglycemia. The cumulative incidence for type 1 diabetes was greater after IND/DYS- than after DYS/IND- ( P < 0.01). Within the normoglycemic cohort, the cumulative incidence of type 1 diabetes was higher after DYS/IND+ than after DYS/IND- ( P < 0.001), whereas within the Index60 <1.00 cohort, the cumulative incidence after IND/DYS+ and after IND/DYS- did not differ significantly. Among nonprogressors, type 1 diabetes risk at the last OGTT was greater for IND/DYS- than for DYS/IND- ( P < 0.001). Hazard ratios (HRs) of DYS/IND- with age and 30- to 0-min C-peptide were positive ( P < 0.001 for both), whereas HRs of type 1 diabetes with these variables were inverse ( P < 0.001 for both). In contrast, HRs of IND/DYS- and type 1 diabetes with age and 30- to 0-min C-peptide were consistent (all inverse [ P < 0.01 for all]). The findings suggest that incident dysglycemia without Index60 ≥1.00 is a suboptimal prediagnostic end point for type 1 diabetes. Measures that include both glucose and C-peptide levels, such as Index60 ≥1.00, appear better suited as prediagnostic end points. © 2017 by the American Diabetes Association.

Bi-harmonic cantilever design for improved measurement sensitivity in tapping-mode atomic force microscopy

Energy Technology Data Exchange (ETDEWEB)

Loganathan, Muthukumaran; Bristow, Douglas A., E-mail: dbristow@mst.edu [Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, Missouri 65401 (United States)

2014-04-15

This paper presents a method and cantilever design for improving the mechanical measurement sensitivity in the atomic force microscopy (AFM) tapping mode. The method uses two harmonics in the drive signal to generate a bi-harmonic tapping trajectory. Mathematical analysis demonstrates that the wide-valley bi-harmonic tapping trajectory is as much as 70% more sensitive to changes in the sample topography than the standard single-harmonic trajectory typically used. Although standard AFM cantilevers can be driven in the bi-harmonic tapping trajectory, they require large forcing at the second harmonic. A design is presented for a bi-harmonic cantilever that has a second resonant mode at twice its first resonant mode, thereby capable of generating bi-harmonic trajectories with small forcing signals. Bi-harmonic cantilevers are fabricated by milling a small cantilever on the interior of a standard cantilever probe using a focused ion beam. Bi-harmonic drive signals are derived for standard cantilevers and bi-harmonic cantilevers. Experimental results demonstrate better than 30% improvement in measurement sensitivity using the bi-harmonic cantilever. Images obtained through bi-harmonic tapping exhibit improved sharpness and surface tracking, especially at high scan speeds and low force fields.

Bi-harmonic cantilever design for improved measurement sensitivity in tapping-mode atomic force microscopy.

Science.gov (United States)

Loganathan, Muthukumaran; Bristow, Douglas A

2014-04-01

This paper presents a method and cantilever design for improving the mechanical measurement sensitivity in the atomic force microscopy (AFM) tapping mode. The method uses two harmonics in the drive signal to generate a bi-harmonic tapping trajectory. Mathematical analysis demonstrates that the wide-valley bi-harmonic tapping trajectory is as much as 70% more sensitive to changes in the sample topography than the standard single-harmonic trajectory typically used. Although standard AFM cantilevers can be driven in the bi-harmonic tapping trajectory, they require large forcing at the second harmonic. A design is presented for a bi-harmonic cantilever that has a second resonant mode at twice its first resonant mode, thereby capable of generating bi-harmonic trajectories with small forcing signals. Bi-harmonic cantilevers are fabricated by milling a small cantilever on the interior of a standard cantilever probe using a focused ion beam. Bi-harmonic drive signals are derived for standard cantilevers and bi-harmonic cantilevers. Experimental results demonstrate better than 30% improvement in measurement sensitivity using the bi-harmonic cantilever. Images obtained through bi-harmonic tapping exhibit improved sharpness and surface tracking, especially at high scan speeds and low force fields.

A hybrid spatio-temporal data indexing method for trajectory databases.

Science.gov (United States)

Ke, Shengnan; Gong, Jun; Li, Songnian; Zhu, Qing; Liu, Xintao; Zhang, Yeting

2014-07-21

In recent years, there has been tremendous growth in the field of indoor and outdoor positioning sensors continuously producing huge volumes of trajectory data that has been used in many fields such as location-based services or location intelligence. Trajectory data is massively increased and semantically complicated, which poses a great challenge on spatio-temporal data indexing. This paper proposes a spatio-temporal data indexing method, named HBSTR-tree, which is a hybrid index structure comprising spatio-temporal R-tree, B*-tree and Hash table. To improve the index generation efficiency, rather than directly inserting trajectory points, we group consecutive trajectory points as nodes according to their spatio-temporal semantics and then insert them into spatio-temporal R-tree as leaf nodes. Hash table is used to manage the latest leaf nodes to reduce the frequency of insertion. A new spatio-temporal interval criterion and a new node-choosing sub-algorithm are also proposed to optimize spatio-temporal R-tree structures. In addition, a B*-tree sub-index of leaf nodes is built to query the trajectories of targeted objects efficiently. Furthermore, a database storage scheme based on a NoSQL-type DBMS is also proposed for the purpose of cloud storage. Experimental results prove that HBSTR-tree outperforms TB*-tree in some aspects such as generation efficiency, query performance and query type.

A Hybrid Spatio-Temporal Data Indexing Method for Trajectory Databases

Directory of Open Access Journals (Sweden)

Shengnan Ke

2014-07-01

Full Text Available In recent years, there has been tremendous growth in the field of indoor and outdoor positioning sensors continuously producing huge volumes of trajectory data that has been used in many fields such as location-based services or location intelligence. Trajectory data is massively increased and semantically complicated, which poses a great challenge on spatio-temporal data indexing. This paper proposes a spatio-temporal data indexing method, named HBSTR-tree, which is a hybrid index structure comprising spatio-temporal R-tree, B*-tree and Hash table. To improve the index generation efficiency, rather than directly inserting trajectory points, we group consecutive trajectory points as nodes according to their spatio-temporal semantics and then insert them into spatio-temporal R-tree as leaf nodes. Hash table is used to manage the latest leaf nodes to reduce the frequency of insertion. A new spatio-temporal interval criterion and a new node-choosing sub-algorithm are also proposed to optimize spatio-temporal R-tree structures. In addition, a B*-tree sub-index of leaf nodes is built to query the trajectories of targeted objects efficiently. Furthermore, a database storage scheme based on a NoSQL-type DBMS is also proposed for the purpose of cloud storage. Experimental results prove that HBSTR-tree outperforms TB*-tree in some aspects such as generation efficiency, query performance and query type.

A Hybrid Spatio-Temporal Data Indexing Method for Trajectory Databases

Science.gov (United States)

Ke, Shengnan; Gong, Jun; Li, Songnian; Zhu, Qing; Liu, Xintao; Zhang, Yeting

2014-01-01

In recent years, there has been tremendous growth in the field of indoor and outdoor positioning sensors continuously producing huge volumes of trajectory data that has been used in many fields such as location-based services or location intelligence. Trajectory data is massively increased and semantically complicated, which poses a great challenge on spatio-temporal data indexing. This paper proposes a spatio-temporal data indexing method, named HBSTR-tree, which is a hybrid index structure comprising spatio-temporal R-tree, B*-tree and Hash table. To improve the index generation efficiency, rather than directly inserting trajectory points, we group consecutive trajectory points as nodes according to their spatio-temporal semantics and then insert them into spatio-temporal R-tree as leaf nodes. Hash table is used to manage the latest leaf nodes to reduce the frequency of insertion. A new spatio-temporal interval criterion and a new node-choosing sub-algorithm are also proposed to optimize spatio-temporal R-tree structures. In addition, a B*-tree sub-index of leaf nodes is built to query the trajectories of targeted objects efficiently. Furthermore, a database storage scheme based on a NoSQL-type DBMS is also proposed for the purpose of cloud storage. Experimental results prove that HBSTR-tree outperforms TB*-tree in some aspects such as generation efficiency, query performance and query type. PMID:25051028

CETF Space Station payload pointing system design and analysis feasibility study. [Critical Evaluation Task Force

Science.gov (United States)

Smagala, Tom; Mcglew, Dave

1988-01-01

The expected pointing performance of an attached payload coupled to the Critical Evaluation Task Force Space Station via a payload pointing system (PPS) is determined. The PPS is a 3-axis gimbal which provides the capability for maintaining inertial pointing of a payload in the presence of disturbances associated with the Space Station environment. A system where the axes of rotation were offset from the payload center of mass (CM) by 10 in. in the Z axis was studied as well as a system having the payload CM offset by only 1 inch. There is a significant improvement in pointing performance when going from the 10 in. to the 1 in. gimbal offset.

Logarithmic spiral trajectories generated by Solar sails

Science.gov (United States)

Bassetto, Marco; Niccolai, Lorenzo; Quarta, Alessandro A.; Mengali, Giovanni

2018-02-01

Analytic solutions to continuous thrust-propelled trajectories are available in a few cases only. An interesting case is offered by the logarithmic spiral, that is, a trajectory characterized by a constant flight path angle and a fixed thrust vector direction in an orbital reference frame. The logarithmic spiral is important from a practical point of view, because it may be passively maintained by a Solar sail-based spacecraft. The aim of this paper is to provide a systematic study concerning the possibility of inserting a Solar sail-based spacecraft into a heliocentric logarithmic spiral trajectory without using any impulsive maneuver. The required conditions to be met by the sail in terms of attitude angle, propulsive performance, parking orbit characteristics, and initial position are thoroughly investigated. The closed-form variations of the osculating orbital parameters are analyzed, and the obtained analytical results are used for investigating the phasing maneuver of a Solar sail along an elliptic heliocentric orbit. In this mission scenario, the phasing orbit is composed of two symmetric logarithmic spiral trajectories connected with a coasting arc.

Cutting force model for high speed machining process

International Nuclear Information System (INIS)

Haber, R. E.; Jimenez, J. E.; Jimenez, A.; Lopez-Coronado, J.

2004-01-01

This paper presents cutting force-based models able to describe a high speed machining process. The model considers the cutting force as output variable, essential for the physical processes that are taking place in high speed machining. Moreover, this paper shows the mathematical development to derive the integral-differential equations, and the algorithms implemented in MATLAB to predict the cutting force in real time MATLAB is a software tool for doing numerical computations with matrices and vectors. It can also display information graphically and includes many toolboxes for several research and applications areas. Two end mill shapes are considered (i. e. cylindrical and ball end mill) for real-time implementation of the developed algorithms. the developed models are validated in slot milling operations. The results corroborate the importance of the cutting force variable for predicting tool wear in high speed machining operations. The developed models are the starting point for future work related with vibration analysis, process stability and dimensional surface finish in high speed machining processes. (Author) 19 refs

UST-ID robotics: Wireless communication and minimum conductor technology, and end-point tracking technology surveys

International Nuclear Information System (INIS)

Holliday, M.A.

1993-10-01

This report is a technology review of the current state-of-the-art in two technologies applicable to the Underground Storage Tank (UST) program at the Hanford Nuclear Reservation. The first review is of wireless and minimal conductor technologies for in-tank communications. The second review is of advanced concepts for independent tool-point tracking. This study addresses the need to provide wireless transmission media or minimum conductor technology for in-tank communications and robot control. At present, signals are conducted via contacting transmission media, i.e., cables. Replacing wires with radio frequencies or invisible light are commonplace in the communication industry. This technology will be evaluated for its applicability to the needs of robotics. Some of these options are radio signals, leaky coax, infrared, microwave, and optical fiber systems. Although optical fiber systems are contacting transmission media, they will be considered because of their ability to reduce the number of conductors. In this report we will identify, evaluate, and recommend the requirements for wireless and minimum conductor technology to replace the present cable system. The second section is a technology survey of concepts for independent end-point tracking (tracking the position of robot end effectors). The position of the end effector in current industrial robots is determined by computing that position from joint information, which is basically a problem of locating a point in three-dimensional space. Several approaches are presently being used in industrial robotics, including: stereo-triangulation with a theodolite network and electrocamera system, photogrammetry, and multiple-length measurement with laser interferometry and wires. The techniques that will be evaluated in this survey are advanced applications of the aforementioned approaches. These include laser tracking (3-D and 5-D), ultrasonic tracking, vision-guided servoing, and adaptive robotic visual tracking

Study on Effect of Ultrasonic Vibration on Grinding Force and Surface Quality in Ultrasonic Assisted Micro End Grinding of Silica Glass

Directory of Open Access Journals (Sweden)

Zhang Jianhua

2014-01-01

Full Text Available Ultrasonic vibration assisted micro end grinding (UAMEG is a promising processing method for micro parts made of hard and brittle materials. First, the influence of ultrasonic assistance on the mechanism of this processing technology is theoretically analyzed. Then, in order to reveal the effects of ultrasonic vibration and grinding parameters on grinding forces and surface quality, contrast grinding tests of silica glass with and without ultrasonic assistance using micro radial electroplated diamond wheel are conducted. The grinding forces are measured using a three-component dynamometer. The surface characteristics are detected using the scanning electron microscope. The experiment results demonstrate that grinding forces are significantly reduced by introducing ultrasonic vibration into conventional micro end grinding (CMEG of silica glass; ultrasonic assistance causes inhibiting effect on variation percentages of tangential grinding force with grinding parameters; ductile machining is easier to be achieved and surface quality is obviously improved due to ultrasonic assistance in UAMEG. Therefore, larger grinding depth and feed rate adopted in UAMEG can lead to the improvement of removal rate and machining efficiency compared with CMEG.

Transformation optics beyond the manipulation of light trajectories.

Science.gov (United States)

Ginis, Vincent; Tassin, Philippe

2015-08-28

Since its inception in 2006, transformation optics has become an established tool to understand and design electromagnetic systems. It provides a geometrical perspective into the properties of light waves without the need for a ray approximation. Most studies have focused on modifying the trajectories of light rays, e.g. beam benders, lenses, invisibility cloaks, etc. In this contribution, we explore transformation optics beyond the manipulation of light trajectories. With a few well-chosen examples, we demonstrate that transformation optics can be used to manipulate electromagnetic fields up to an unprecedented level. In the first example, we introduce an electromagnetic cavity that allows for deep subwavelength confinement of light. The cavity is designed with transformation optics even though the concept of trajectory ceases to have any meaning in a structure as small as this cavity. In the second example, we show that the properties of Cherenkov light emitted in a transformation-optical material can be understood and modified from simple geometric considerations. Finally, we show that optical forces--a quadratic function of the fields--follow the rules of transformation optics too. By applying a folded coordinate transformation to a pair of waveguides, optical forces can be enhanced just as if the waveguides were closer together. With these examples, we open up an entirely new spectrum of devices that can be conceived using transformation optics. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Stable long-time semiclassical description of zero-point energy in high-dimensional molecular systems.

Science.gov (United States)

Garashchuk, Sophya; Rassolov, Vitaly A

2008-07-14

Semiclassical implementation of the quantum trajectory formalism [J. Chem. Phys. 120, 1181 (2004)] is further developed to give a stable long-time description of zero-point energy in anharmonic systems of high dimensionality. The method is based on a numerically cheap linearized quantum force approach; stabilizing terms compensating for the linearization errors are added into the time-evolution equations for the classical and nonclassical components of the momentum operator. The wave function normalization and energy are rigorously conserved. Numerical tests are performed for model systems of up to 40 degrees of freedom.

Trajectory Correction and Locomotion Analysis of a Hexapod Walking Robot with Semi-Round Rigid Feet

Science.gov (United States)

Zhu, Yaguang; Jin, Bo; Wu, Yongsheng; Guo, Tong; Zhao, Xiangmo

2016-01-01

Aimed at solving the misplaced body trajectory problem caused by the rolling of semi-round rigid feet when a robot is walking, a legged kinematic trajectory correction methodology based on the Least Squares Support Vector Machine (LS-SVM) is proposed. The concept of ideal foothold is put forward for the three-dimensional kinematic model modification of a robot leg, and the deviation value between the ideal foothold and real foothold is analyzed. The forward/inverse kinematic solutions between the ideal foothold and joint angular vectors are formulated and the problem of direct/inverse kinematic nonlinear mapping is solved by using the LS-SVM. Compared with the previous approximation method, this correction methodology has better accuracy and faster calculation speed with regards to inverse kinematics solutions. Experiments on a leg platform and a hexapod walking robot are conducted with multi-sensors for the analysis of foot tip trajectory, base joint vibration, contact force impact, direction deviation, and power consumption, respectively. The comparative analysis shows that the trajectory correction methodology can effectively correct the joint trajectory, thus eliminating the contact force influence of semi-round rigid feet, significantly improving the locomotion of the walking robot and reducing the total power consumption of the system. PMID:27589766

Cicada (Tibicen linnei steers by force vectoring

Directory of Open Access Journals (Sweden)

Samane Zeyghami

2016-03-01

Full Text Available To change flight direction, flying animals modulate aerodynamic force either relative to their bodies to generate torque about the center of mass, or relative to the flight path to produce centripetal force that curves the trajectory. In employing the latter, the direction of aerodynamic force remains fixed in the body frame and rotations of the body redirect the force. While both aforementioned techniques are essential for flight, it is critical to investigate how an animal balances the two to achieve aerial locomotion. Here, we measured wing and body kinematics of cicada (Tibicen linnei in free flight, including flight periods of both little and substantial body reorientations. It is found that cicadas employ a common force vectoring technique to execute all these flights. We show that the direction of the half-stroke averaged aerodynamic force relative to the body is independent of the body orientation, varying in a range of merely 20 deg. Despite directional limitation of the aerodynamic force, pitch and roll torque are generated by altering wing angle of attack and its mean position relative to the center of mass. This results in body rotations which redirect the wing force in the global frame and consequently change the flight trajectory.

Visualization study for forced convection heat transfer of supercritical carbon dioxide near pseudo-boiling point

International Nuclear Information System (INIS)

Sakurai, K.; Ko, H.S.; Okamoto, K.; Madarame, H.

2001-01-01

For development of new reactor, supercritical water is expected to be used as coolant to improve thermal efficiency. However, the thermal characteristics of supercritical fluid is not revealed completely because its difficulty for experiment. Specific phenomena tend to occur near the pseudo-boiling point which is characterised by temperature corresponding to the saturation point in ordinary fluid. Around this point, the physic properties such as density, specific heat and thermal conductivity are drastically varying. Although there is no difference between gas and liquid phases in supercritical fluids, phenomena similar to boiling (with heat transfer deterioration) can be observed round the pseudo-boiling point. Experiments of heat transfer have been done for supercritical fluid in forced convective condition. However, these experiments were mainly realised inside stainless steel cylinder pipes, for which flow visualisation is difficult. Consequently, this work has been devoted to the development of method allowing the visualisation of supercritical flows. The experiment setup is composed of main loop and test section for the visualisation. Carbon dioxide is used as test fluid. Supercritical carbon dioxide flows upward in rectangular channel and heated by one-side wall to generate forced convection heat transfer. Through window at mid-height of the test section, shadowgraphy was applied to visualize density gradient distribution. The behavior of the density wave in the channel is visualized and examined through the variation of the heat transfer coefficient. (author)

End of the "Little Ice Age" in the Alps not forced by industrial black carbon

Science.gov (United States)

Sigl, Michael; Osmont, Dimtri; Gabrieli, Jacopo; Barbante, Carlo; Schwikowski, Margit

2016-04-01

Light absorbing aerosols present in the atmosphere and cryosphere play an important role in the climate system. Their presence in ambient air and snow changes radiative properties of these media, thus contributing to increased atmospheric warming and snowmelt. High spatio-temporal variability of aerosol concentrations in these media and a shortage of long-term observations contribute to large uncertainties in properly assigning the climate effects of these aerosols through time. Glaciers in the European Alps began to retreat abruptly from their mid-19th century maximum, marking what appeared to be the end of the Little Ice Age. Radiative forcing by increasing deposition of industrial black carbon to snow has been suggested as the main driver of the abrupt glacier retreats in the Alps (Painter et al. 2012). Basis for this hypothesis were model simulations using ice-core measurements of elemental carbon at low temporal resolution from two ice cores in the Alps. Here we present sub-annually resolved, well replicated ice-core measurements of refractory black carbon (rBC; using a SP2 soot photometer), mineral dust (Fe, Ca), biomass burning (NH4, K) and distinctive industrial pollution tracers (Bi, Pb, SO4) from an ice core in the Alps covering the past 250 years. These reconstructions allow to precisely compare the timing of observed acceleration of glacier melt in the mid-19th century with that of the increase of soot deposition on ice-sheets caused by the industrialization of Western Europe. Our study suggests that at the time when European rBC emission rates started to significantly increase Alpine glaciers have already experienced more than 70% of their total 19th century length reduction. Industrial BC emissions can therefore not been considered as the primary forcing of the rapid deglaciation at the end of the Little Ice Age in the Alps. References: Painter, T. H., M. G. Flanner, G. Kaser, B. Marzeion, R. A. VanCuren, and W. Abdalati (2013), End of the Little Ice

Comparison of kinematic and dynamic leg trajectory optimization techniques for biped robot locomotion

Science.gov (United States)

Khusainov, R.; Klimchik, A.; Magid, E.

2017-01-01

The paper presents comparison analysis of two approaches in defining leg trajectories for biped locomotion. The first one operates only with kinematic limitations of leg joints and finds the maximum possible locomotion speed for given limits. The second approach defines leg trajectories from the dynamic stability point of view and utilizes ZMP criteria. We show that two methods give different trajectories and demonstrate that trajectories based on pure dynamic optimization cannot be realized due to joint limits. Kinematic optimization provides unstable solution which can be balanced by upper body movement.

Job satisfaction developmental trajectories and health: A life course perspective.

Science.gov (United States)

Dirlam, Jonathan; Zheng, Hui

2017-04-01

Understanding the health consequence of job dissatisfaction becomes increasingly important because job insecurity, stress and dissatisfaction have significantly increased in the United States in the last decade. Despite the extensive work in this area, prior studies nonetheless may underestimate the harmful effect of job dissatisfaction due to the cross-sectional nature of their data and sample selection bias. This study applies a life-course approach to more comprehensively examine the relationship between job satisfaction and health. Using data from the NLSY 1979 cohort, we estimate group based job satisfaction trajectories of respondents starting at age 25 and ending at age 39. Four job satisfaction trajectory groups are identified, a consistently high satisfaction group, a downward group, an upward group, and a lowest satisfaction group. We examine the effects of these trajectories on several physical and mental health outcomes of respondents in their early forties. We find membership in the lowest job satisfaction trajectory group to be negatively associated with all five mental health outcomes, supporting the accumulation of risks life course model. Those in the upward job satisfaction trajectory group have similar health outcomes to those in the high job satisfaction trajectory group, supporting the social mobility life course model. Overall, we find the relationship between job satisfaction trajectories and health to be stronger for mental health compared to physical health. Copyright © 2017 Elsevier Ltd. All rights reserved.

WE-AB-209-06: Dynamic Collimator Trajectory Algorithm for Use in VMAT Treatment Deliveries

Energy Technology Data Exchange (ETDEWEB)

MacDonald, L [Department of Medical Physics, Dalhousie University, Halifax, Nova Scotia, CA (Canada); Thomas, C; Syme, A [Department of Medical Physics, Dalhousie University, Halifax, Nova Scotia, CA (Canada); Department of Radiation Oncology, Dalhousie University, Halifax, Nova Scotia (Canada); Medical Physics, Nova Scotia Cancer Centre, Halifax, Nova Scotia (Canada)

2016-06-15

Purpose: To develop advanced dynamic collimator positioning algorithms for optimal beam’s-eye-view (BEV) fitting of targets in VMAT procedures, including multiple metastases stereotactic radiosurgery procedures. Methods: A trajectory algorithm was developed, which can dynamically modify the angle of the collimator as a function of VMAT control point to provide optimized collimation of target volume(s). Central to this algorithm is a concept denoted “whitespace”, defined as area within the jaw-defined BEV field, outside of the PTV, and not shielded by the MLC when fit to the PTV. Calculating whitespace at all collimator angles and every control point, a two-dimensional topographical map depicting the tightness-of-fit of the MLC was generated. A variety of novel searching algorithms identified a number of candidate trajectories of continuous collimator motion. Ranking these candidate trajectories according to their accrued whitespace value produced an optimal solution for navigation of this map. Results: All trajectories were normalized to minimum possible (i.e. calculated without consideration of collimator motion constraints) accrued whitespace. On an acoustic neuroma case, a random walk algorithm generated a trajectory with 151% whitespace; random walk including a mandatory anchor point improved this to 148%; gradient search produced a trajectory with 137%; and bi-directional gradient search generated a trajectory with 130% whitespace. For comparison, a fixed collimator angle of 30° and 330° accumulated 272% and 228% of whitespace, respectively. The algorithm was tested on a clinical case with two metastases (single isocentre) and identified collimator angles that allow for simultaneous irradiation of the PTVs while minimizing normal tissue irradiation. Conclusion: Dynamic collimator trajectories have the potential to improve VMAT deliveries through increased efficiency and reduced normal tissue dose, especially in treatment of multiple cranial metastases

WE-AB-209-06: Dynamic Collimator Trajectory Algorithm for Use in VMAT Treatment Deliveries

International Nuclear Information System (INIS)

MacDonald, L; Thomas, C; Syme, A

2016-01-01

Purpose: To develop advanced dynamic collimator positioning algorithms for optimal beam’s-eye-view (BEV) fitting of targets in VMAT procedures, including multiple metastases stereotactic radiosurgery procedures. Methods: A trajectory algorithm was developed, which can dynamically modify the angle of the collimator as a function of VMAT control point to provide optimized collimation of target volume(s). Central to this algorithm is a concept denoted “whitespace”, defined as area within the jaw-defined BEV field, outside of the PTV, and not shielded by the MLC when fit to the PTV. Calculating whitespace at all collimator angles and every control point, a two-dimensional topographical map depicting the tightness-of-fit of the MLC was generated. A variety of novel searching algorithms identified a number of candidate trajectories of continuous collimator motion. Ranking these candidate trajectories according to their accrued whitespace value produced an optimal solution for navigation of this map. Results: All trajectories were normalized to minimum possible (i.e. calculated without consideration of collimator motion constraints) accrued whitespace. On an acoustic neuroma case, a random walk algorithm generated a trajectory with 151% whitespace; random walk including a mandatory anchor point improved this to 148%; gradient search produced a trajectory with 137%; and bi-directional gradient search generated a trajectory with 130% whitespace. For comparison, a fixed collimator angle of 30° and 330° accumulated 272% and 228% of whitespace, respectively. The algorithm was tested on a clinical case with two metastases (single isocentre) and identified collimator angles that allow for simultaneous irradiation of the PTVs while minimizing normal tissue irradiation. Conclusion: Dynamic collimator trajectories have the potential to improve VMAT deliveries through increased efficiency and reduced normal tissue dose, especially in treatment of multiple cranial metastases

Trajectory Planning for Robots in Dynamic Human Environments

DEFF Research Database (Denmark)

Svenstrup, Mikael; Bak, Thomas; Andersen, Hans Jørgen

2010-01-01

This paper present a trajectory planning algorithm for a robot operating in dynamic human environments. Environments such as pedestrian streets, hospital corridors and train stations. We formulate the problem as planning a minimal cost trajectory through a potential field, defined from...... is enhanced to direct the search and account for the kinodynamic robot constraints. Compared to standard RRT, the algorithm proposed here find the robot control input that will drive the robot towards a new sampled point in the configuration space. The effect of the input is simulated, to add a reachable...

Quantum trajectories in complex space: One-dimensional stationary scattering problems

International Nuclear Information System (INIS)

Chou, C.-C.; Wyatt, Robert E.

2008-01-01

One-dimensional time-independent scattering problems are investigated in the framework of the quantum Hamilton-Jacobi formalism. The equation for the local approximate quantum trajectories near the stagnation point of the quantum momentum function is derived, and the first derivative of the quantum momentum function is related to the local structure of quantum trajectories. Exact complex quantum trajectories are determined for two examples by numerically integrating the equations of motion. For the soft potential step, some particles penetrate into the nonclassical region, and then turn back to the reflection region. For the barrier scattering problem, quantum trajectories may spiral into the attractors or from the repellers in the barrier region. Although the classical potentials extended to complex space show different pole structures for each problem, the quantum potentials present the same second-order pole structure in the reflection region. This paper not only analyzes complex quantum trajectories and the total potentials for these examples but also demonstrates general properties and similar structures of the complex quantum trajectories and the quantum potentials for one-dimensional time-independent scattering problems

End of the Little Ice Age in the Alps forced by industrial black carbon.

Science.gov (United States)

Painter, Thomas H; Flanner, Mark G; Kaser, Georg; Marzeion, Ben; VanCuren, Richard A; Abdalati, Waleed

2013-09-17

Glaciers in the European Alps began to retreat abruptly from their mid-19th century maximum, marking what appeared to be the end of the Little Ice Age. Alpine temperature and precipitation records suggest that glaciers should instead have continued to grow until circa 1910. Radiative forcing by increasing deposition of industrial black carbon to snow may represent the driver of the abrupt glacier retreats in the Alps that began in the mid-19th century. Ice cores indicate that black carbon concentrations increased abruptly in the mid-19th century and largely continued to increase into the 20th century, consistent with known increases in black carbon emissions from the industrialization of Western Europe. Inferred annual surface radiative forcings increased stepwise to 13-17 W⋅m(-2) between 1850 and 1880, and to 9-22 W⋅m(-2) in the early 1900s, with snowmelt season (April/May/June) forcings reaching greater than 35 W⋅m(-2) by the early 1900s. These snowmelt season radiative forcings would have resulted in additional annual snow melting of as much as 0.9 m water equivalent across the melt season. Simulations of glacier mass balances with radiative forcing-equivalent changes in atmospheric temperatures result in conservative estimates of accumulating negative mass balances of magnitude -15 m water equivalent by 1900 and -30 m water equivalent by 1930, magnitudes and timing consistent with the observed retreat. These results suggest a possible physical explanation for the abrupt retreat of glaciers in the Alps in the mid-19th century that is consistent with existing temperature and precipitation records and reconstructions.

Tactile Robotic Topographical Mapping Without Force or Contact Sensors

Science.gov (United States)

Burke, Kevin; Melko, Joseph; Krajewski, Joel; Cady, Ian

2008-01-01

A method of topographical mapping of a local solid surface within the range of motion of a robot arm is based on detection of contact between the surface and the end effector (the fixture or tool at the tip of the robot arm). The method was conceived to enable mapping of local terrain by an exploratory robot on a remote planet, without need to incorporate delicate contact switches, force sensors, a vision system, or other additional, costly hardware. The method could also be used on Earth for determining the size and shape of an unknown surface in the vicinity of a robot, perhaps in an unanticipated situation in which other means of mapping (e.g., stereoscopic imaging or laser scanning with triangulation) are not available. The method uses control software modified to utilize the inherent capability of the robotic control system to measure the joint positions, the rates of change of the joint positions, and the electrical current demanded by the robotic arm joint actuators. The system utilizes these coordinate data and the known robot-arm kinematics to compute the position and velocity of the end effector, move the end effector along a specified trajectory, place the end effector at a specified location, and measure the electrical currents in the joint actuators. Since the joint actuator current is approximately proportional to the actuator forces and torques, a sudden rise in joint current, combined with a slowing of the joint, is a possible indication of actuator stall and surface contact. Hence, even though the robotic arm is not equipped with contact sensors, it is possible to sense contact (albeit with reduced sensitivity) as the end effector becomes stalled against a surface that one seeks to measure.

Pilot study on quantitative assessment of muscle imbalance: differences of muscle synergies, equilibrium-point trajectories, and endpoint stiffness in normal and pathological upper-limb movements.

Science.gov (United States)

Oku, Takanori; Uno, Kanna; Nishi, Tomoki; Kageyama, Masayuki; Phatiwuttipat, Pipatthana; Koba, Keitaro; Yamashita, Yuto; Murakami, Kenta; Uemura, Mitsunori; Hirai, Hiroaki; Miyazaki, Fumio; Naritomi, Hiroaki

2014-01-01

This paper proposes a novel method for assessment of muscle imbalance based on muscle synergy hypothesis and equilibrium point (EP) hypothesis of motor control. We explain in detail the method for extracting muscle synergies under the concept of agonist-antagonist (AA) muscle pairs and for estimating EP trajectories and endpoint stiffness of human upper limbs in a horizontal plane using an electromyogram. The results of applying this method to the reaching movement of one normal subject and one hemiplegic subject suggest that (1) muscle synergies (the balance among coactivation of AA muscle pairs), particularly the synergies that contributes to the angular directional kinematics of EP and the limb stiffness, are quite different between the normal subject and the hemiplegic subject; (2) the concomitant EP trajectory is also different between the normal and hemiplegic subjects, corresponding to the difference of muscle synergies; and (3) the endpoint (hand) stiffness ellipse of the hemiplegic subject becomes more elongated and orientation of the major axis rotates clockwise more than that of the normal subject. The level of motor impairment would be expected to be assessed from a comparison of these differences of muscle synergies, EP trajectories, and endpoint stiffness among normal and pathological subjects using the method.

Robot trajectory tracking with self-tuning predicted control

Science.gov (United States)

Cui, Xianzhong; Shin, Kang G.

1988-01-01

A controller that combines self-tuning prediction and control is proposed for robot trajectory tracking. The controller has two feedback loops: one is used to minimize the prediction error, and the other is designed to make the system output track the set point input. Because the velocity and position along the desired trajectory are given and the future output of the system is predictable, a feedforward loop can be designed for robot trajectory tracking with self-tuning predicted control (STPC). Parameters are estimated online to account for the model uncertainty and the time-varying property of the system. The authors describe the principle of STPC, analyze the system performance, and discuss the simplification of the robot dynamic equations. To demonstrate its utility and power, the controller is simulated for a Stanford arm.

Reconstruction of equilibrium trajectories during whole-body movements.

Science.gov (United States)

Domen, K; Latash, M L; Zatsiorsky, V M

1999-03-01

The framework of the equilibrium-point hypothesis was used to reconstruct equilibrium trajectories (ETs) of the ankle, hip and body center of mass during quick voluntary hip flexions ('Japanese courtesy bow') by standing subjects. Different spring loads applied to the subject's back were used to introduce smooth perturbations that are necessary to reconstruct ETs based on a series of trials at the same task. Time patterns of muscle torques were calculated using inverse dynamics techniques. A second-order linear model was employed to calculate the instantaneous position of the spring-like joint or center of mass characteristic at different times during the movement. ETs of the joints and of the center of mass had significantly different shapes from the actual trajectories. Integral measures of electromyographic bursts of activity in postural muscles demonstrated a relation to muscle length corresponding to the equilibrium-point hypothesis.

The nuclear force problem: Is the never-ending story coming to an end?

International Nuclear Information System (INIS)

Machleidt, R.

2006-01-01

The attempts to find the right (underlying) theory for the nuclear force have a long and stimulating history. Already in 1953, Hans Bethe stated that “more man-hours have been given to this problem than to any other scientific question in the history of mankind”. In search for the nature of the nuclear force, the idea of sub-nuclear particles was created which, eventually, generated the field of particle physics. I will review this productive history of hope, error, and desperation. Finally, I will discuss recent ideas which apply the concept of an effective field theory to low-energy QCD. There are indications that this concept may provide the right framework to properly understand nuclear forces.

Observation of particle trajectories near a magnetized fiber

International Nuclear Information System (INIS)

Treat, R.P.; Lawson, W.F.; Johnson, J.L.

1979-01-01

The motions of 20--30-μm paramagnetic particles have been observed in the neighborhood of a 250-μm ferromagnetic fiber. The particles are entrained in nitrogen flowing down over a horizontal fiber. The particles and fiber are magnetized by a vertical magnetic field of strength up to 0.73 T. The free-stream velocities range from nearly zero to 1 m/sec. A Fastax movie camera is used to record the positions of the particles as they pass by or collide with the fiber. The particle trajectories thus observed determine the collision cross section as a function of field strength and free-stream velocity. Cross sections of over five diameters are observed. The cross sections and trajectories are compared and agree with the Newtonian theory of the particle motion. The theory assumes potential flow over the fiber and accounts for the magnetic, viscous, and gravitational forces and particle inertia, all of these being significant in the range of conditions considered. The observed trajectories show details of the motion which are clear manifestations of particle inertia. The sharp particle shadows cast by the isolated fiber are a striking feature of the trajectory patterns. Such shadows should be the source of an intereference effect in multiple-fiber filters

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

Science.gov (United States)

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

2006-05-01

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

Point Clouds to Indoor/outdoor Accessibility Diagnosis

Science.gov (United States)

Balado, J.; Díaz-Vilariño, L.; Arias, P.; Garrido, I.

2017-09-01

This work presents an approach to automatically detect structural floor elements such as steps or ramps in the immediate environment of buildings, elements that may affect the accessibility to buildings. The methodology is based on Mobile Laser Scanner (MLS) point cloud and trajectory information. First, the street is segmented in stretches along the trajectory of the MLS to work in regular spaces. Next, the lower region of each stretch (the ground zone) is selected as the ROI and normal, curvature and tilt are calculated for each point. With this information, points in the ROI are classified in horizontal, inclined or vertical. Points are refined and grouped in structural elements using raster process and connected components in different phases for each type of previously classified points. At last, the trajectory data is used to distinguish between road and sidewalks. Adjacency information is used to classify structural elements in steps, ramps, curbs and curb-ramps. The methodology is tested in a real case study, consisting of 100 m of an urban street. Ground elements are correctly classified in an acceptable computation time. Steps and ramps also are exported to GIS software to enrich building models from Open Street Map with information about accessible/inaccessible entrances and their locations.

Scale-invariant transition probabilities in free word association trajectories

Directory of Open Access Journals (Sweden)

Martin Elias Costa

2009-09-01

Full Text Available Free-word association has been used as a vehicle to understand the organization of human thoughts. The original studies relied mainly on qualitative assertions, yielding the widely intuitive notion that trajectories of word associations are structured, yet considerably more random than organized linguistic text. Here we set to determine a precise characterization of this space, generating a large number of word association trajectories in a web implemented game. We embedded the trajectories in the graph of word co-occurrences from a linguistic corpus. To constrain possible transport models we measured the memory loss and the cycling probability. These two measures could not be reconciled by a bounded diffusive model since the cycling probability was very high (16 % of order-2 cycles implying a majority of short-range associations whereas the memory loss was very rapid (converging to the asymptotic value in ∼ 7 steps which, in turn, forced a high fraction of long-range associations. We show that memory loss and cycling probabilities of free word association trajectories can be simultaneously accounted by a model in which transitions are determined by a scale invariant probability distribution.

Sustaining trajectory flexibility for air traffic complexity alleviation

Science.gov (United States)

Hasan, Saam N.; Rossiter, J. A.

2012-11-01

Despite the fact that several Air Traffic Management (ATM) complexity metrics have been proposed in the past few years, very few of these studies incorporate a control independent intrinsic approach to the problem with the aim of sustaining trajectory flexibility. This paper proposes the introduction of novel decision making metrics for sustaining user trajectory flexibility. The hypothesis is, if all aircraft apply a flexibility preservation function, complexity may reduce automatically. The functions proposed combine concepts of adaptability, robustness and intrinsic traffic complexity metrics based on Lyapunov exponents. Adaptability is defined as a measure of the ability of the aircraft to change its planned trajectory in response to the occurrence of a disturbance that renders the current planned trajectory infeasible. The Robustness metric is defined as the ability of the aircraft to keep its planned trajectory unchanged in response to the occurrence of disturbances. An Intrinsic complexity measure is used to evaluate the level of disorder with regards to the aircraft trajectory; disorder is defined in this context as the level of consistency in the flow patterns of aircraft and their proximity. A point mass model for multiple aircraft(s) is used to extract the trajectories and computing a form of characterisation of sensitivity and interdependencies of a set of aircraft trajectories. Lyapunov exponents are used to compute this measure. The main contribution of this paper will be to test the hypothesis by combining the complexity metrics described above. Different operational scenarios are simulated using a airspace environment developed in MATLAB which shows how well the traffic is structured by varying the metrics defined. The simulation shows the efficacy of the metrics to alleviate complexity in a heavily congested airspace.

Pharmaceutics, Drug Delivery and Pharmaceutical Technology: A New Test Unit for Disintegration End-Point Determination of Orodispersible Films.

Science.gov (United States)

Low, Ariana; Kok, Si Ling; Khong, Yuetmei; Chan, Sui Yung; Gokhale, Rajeev

2015-11-01

No standard time or pharmacopoeia disintegration test method for orodispersible films (ODFs) exists. The USP disintegration test for tablets and capsules poses significant challenges for end-point determination when used for ODFs. We tested a newly developed disintegration test unit (DTU) against the USP disintegration test. The DTU is an accessory to the USP disintegration apparatus. It holds the ODF in a horizontal position, allowing top-view of the ODF during testing. A Gauge R&R study was conducted to assign relative contributions of the total variability from the operator, sample or the experimental set-up. Precision was compared using commercial ODF products in different media. Agreement between the two measurement methods was analysed. The DTU showed improved repeatability and reproducibility compared to the USP disintegration system with tighter standard deviations regardless of operator or medium. There is good agreement between the two methods, with the USP disintegration test giving generally longer disintegration times possibly due to difficulty in end-point determination. The DTU provided clear end-point determination and is suitable for quality control of ODFs during product developmental stage or manufacturing. This may facilitate the development of a standardized methodology for disintegration time determination of ODFs. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:3893-3903, 2015. Copyright © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Adaptive Mesh Iteration Method for Trajectory Optimization Based on Hermite-Pseudospectral Direct Transcription

Directory of Open Access Journals (Sweden)

Humin Lei

2017-01-01

Full Text Available An adaptive mesh iteration method based on Hermite-Pseudospectral is described for trajectory optimization. The method uses the Legendre-Gauss-Lobatto points as interpolation points; then the state equations are approximated by Hermite interpolating polynomials. The method allows for changes in both number of mesh points and the number of mesh intervals and produces significantly smaller mesh sizes with a higher accuracy tolerance solution. The derived relative error estimate is then used to trade the number of mesh points with the number of mesh intervals. The adaptive mesh iteration method is applied successfully to the examples of trajectory optimization of Maneuverable Reentry Research Vehicle, and the simulation experiment results show that the adaptive mesh iteration method has many advantages.

Measuring protein isoelectric points by AFM-based force spectroscopy using trace amounts of sample

Science.gov (United States)

Guo, Shifeng; Zhu, Xiaoying; Jańczewski, Dominik; Lee, Serina Siew Chen; He, Tao; Teo, Serena Lay Ming; Vancso, G. Julius

2016-09-01

Protein charge at various pH and isoelectric point (pI) values is important in understanding protein function. However, often only trace amounts of unknown proteins are available and pI measurements cannot be obtained using conventional methods. Here, we show a method based on the atomic force microscope (AFM) to determine pI using minute quantities of proteins. The protein of interest is immobilized on AFM colloidal probes and the adhesion force of the protein is measured against a positively and a negatively charged substrate made by layer-by-layer deposition of polyelectrolytes. From the AFM force-distance curves, pI values with an estimated accuracy of ±0.25 were obtained for bovine serum albumin, myoglobin, fibrinogen and ribonuclease A over a range of 4.7-9.8. Using this method, we show that the pI of the ‘footprint’ of the temporary adhesive proteins secreted by the barnacle cyprid larvae of Amphibalanus amphitrite is in the range 9.6-9.7.

Minimizing tip-sample forces in jumping mode atomic force microscopy in liquid

Energy Technology Data Exchange (ETDEWEB)

Ortega-Esteban, A. [Departamento de Fisica de la Materia Condensada, C-3, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Horcas, I. [Nanotec Electronica S.L., Centro Empresarial Euronova 3, Ronda de Poniente 12, 28760 Tres Cantos, Madrid (Spain); Hernando-Perez, M. [Departamento de Fisica de la Materia Condensada, C-3, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Ares, P. [Nanotec Electronica S.L., Centro Empresarial Euronova 3, Ronda de Poniente 12, 28760 Tres Cantos, Madrid (Spain); Perez-Berna, A.J.; San Martin, C.; Carrascosa, J.L. [Centro Nacional de Biotecnologia (CNB-CSIC), Darwin 3, 28049 Madrid (Spain); Pablo, P.J. de [Departamento de Fisica de la Materia Condensada, C-3, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Gomez-Herrero, J., E-mail: julio.gomez@uam.es [Departamento de Fisica de la Materia Condensada, C-3, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain)

2012-03-15

Control and minimization of tip-sample interaction forces are imperative tasks to maximize the performance of atomic force microscopy. In particular, when imaging soft biological matter in liquids, the cantilever dragging force prevents identification of the tip-sample mechanical contact, resulting in deleterious interaction with the specimen. In this work we present an improved jumping mode procedure that allows detecting the tip-sample contact with high accuracy, thus minimizing the scanning forces ({approx}100 pN) during the approach cycles. To illustrate this method we report images of human adenovirus and T7 bacteriophage particles which are prone to uncontrolled modifications when using conventional jumping mode. -- Highlights: Black-Right-Pointing-Pointer Improvement in atomic force microscopy in buffer solution. Black-Right-Pointing-Pointer Peak force detection. Black-Right-Pointing-Pointer Subtracting the cantilever dragging force. Black-Right-Pointing-Pointer Forces in the 100 pN range. Black-Right-Pointing-Pointer Imaging of delicate viruses with atomic force microscopy.

An Optimization-Based Impedance Approach for Robot Force Regulation with Prescribed Force Limits

Directory of Open Access Journals (Sweden)

R. de J. Portillo-Vélez

2015-01-01

Full Text Available An optimization based approach for the regulation of excessive or insufficient forces at the end-effector level is introduced. The objective is to minimize the interaction force error at the robot end effector, while constraining undesired interaction forces. To that end, a dynamic optimization problem (DOP is formulated considering a dynamic robot impedance model. Penalty functions are considered in the DOP to handle the constraints on the interaction force. The optimization problem is online solved through the gradient flow approach. Convergence properties are presented and the stability is drawn when the force limits are considered in the analysis. The effectiveness of our proposal is validated via experimental results for a robotic grasping task.

Is automated kinetic measurement superior to end-point for advanced oxidation protein product?

Science.gov (United States)

Oguz, Osman; Inal, Berrin Bercik; Emre, Turker; Ozcan, Oguzhan; Altunoglu, Esma; Oguz, Gokce; Topkaya, Cigdem; Guvenen, Guvenc

2014-01-01

Advanced oxidation protein product (AOPP) was first described as an oxidative protein marker in chronic uremic patients and measured with a semi-automatic end-point method. Subsequently, the kinetic method was introduced for AOPP assay. We aimed to compare these two methods by adapting them to a chemistry analyzer and to investigate the correlation between AOPP and fibrinogen, the key molecule responsible for human plasma AOPP reactivity, microalbumin, and HbA1c in patients with type II diabetes mellitus (DM II). The effects of EDTA and citrate-anticogulated tubes on these two methods were incorporated into the study. This study included 93 DM II patients (36 women, 57 men) with HbA1c levels > or = 7%, who were admitted to the diabetes and nephrology clinics. The samples were collected in EDTA and in citrate-anticoagulated tubes. Both methods were adapted to a chemistry analyzer and the samples were studied in parallel. In both types of samples, we found a moderate correlation between the kinetic and the endpoint methods (r = 0.611 for citrate-anticoagulated, r = 0.636 for EDTA-anticoagulated, p = 0.0001 for both). We found a moderate correlation between fibrinogen-AOPP and microalbumin-AOPP levels only in the kinetic method (r = 0.644 and 0.520 for citrate-anticoagulated; r = 0.581 and 0.490 for EDTA-anticoagulated, p = 0.0001). We conclude that adaptation of the end-point method to automation is more difficult and it has higher between-run CV% while application of the kinetic method is easier and it may be used in oxidative stress studies.

Theoretical assessment of the disparity in the electrostatic forces between two point charges and two conductive spheres of equal radii

Science.gov (United States)

Kolikov, Kiril

2016-11-01

The Coulomb's formula for the force FC of electrostatic interaction between two point charges is well known. In reality, however, interactions occur not between point charges, but between charged bodies of certain geometric form, size and physical structure. This leads to deviation of the estimated force FC from the real force F of electrostatic interaction, thus imposing the task to evaluate the disparity. In the present paper the problem is being solved theoretically for two charged conductive spheres of equal radii and arbitrary electric charges. Assessment of the deviation is given as a function of the ratio of the distance R between the spheres centers to the sum of their radii. For the purpose, relations between FC and F derived in a preceding work of ours, are employed to generalize the Coulomb's interactions. At relatively short distances between the spheres, the Coulomb force FC, as estimated to be induced by charges situated at the centers of the spheres, differ significantly from the real force F of interaction between the spheres. In the case of zero and non-zero charge we prove that with increasing the distance between the two spheres, the force F decrease rapidly, virtually to zero values, i.e. it appears to be short-acting force.

"These things are dangerous": Understanding induced abortion trajectories in urban Zambia.

Science.gov (United States)

Coast, Ernestina; Murray, Susan F

2016-03-01

Unsafe abortion is a significant but preventable cause of global maternal mortality and morbidity. Zambia has among the most liberal abortion laws in sub-Saharan Africa, however this alone does not guarantee access to safe abortion, and 30% of maternal mortality is attributable to unsafe procedures. Too little is known about the pathways women take to reach abortion services in such resource-poor settings, or what informs care-seeking behaviours, barriers and delays. In-depth qualitative interviews were conducted in 2013 with 112 women who accessed abortion-related care in a Lusaka tertiary government hospital at some point in their pathway. The sample included women seeking safe abortion and also those receiving hospital care following unsafe abortion. We identified a typology of three care-seeking trajectories that ended in the use of hospital services: clinical abortion induced in hospital; clinical abortion initiated elsewhere, with post-abortion care in hospital; and non-clinical abortion initiated elsewhere, with post-abortion care in hospital. Framework analyses of 70 transcripts showed that trajectories to a termination of an unwanted pregnancy can be complex and iterative. Individuals may navigate private and public formal healthcare systems and consult unqualified providers, often trying multiple strategies. We found four major influences on which trajectory a woman followed, as well as the complexity and timing of her trajectory: i) the advice of trusted others ii) perceptions of risk iii) delays in care-seeking and receipt of services and iv) economic cost. Even though abortion is legal in Zambia, girls and women still take significant risks to terminate unwanted pregnancies. Levels of awareness about the legality of abortion and its provision remain low even in urban Zambia, especially among adolescents. Unofficial payments required by some providers can be a major barrier to safe care. Timely access to safe abortion services depends on chance rather

Trajectories and Maneuvers of Surrounding Vehicles with Panoramic Camera Arrays

DEFF Research Database (Denmark)

Dueholm, Jacob Velling; Kristoffersen, Miklas Strøm; Satzoda, Ravi K.

2016-01-01

Vision-based research for intelligent vehicles have traditionally focused on specific regions around a vehicle, such as a front looking camera for, e.g., lane estimation. Traffic scenes are complex and vital information could be lost in unobserved regions. This paper proposes a framework that uses...... four visual sensors for a full surround view of a vehicle in order to achieve an understanding of surrounding vehicle behaviors. The framework will assist the analysis of naturalistic driving studies by automating the task of data reduction of the observed trajectories. To this end, trajectories...... are estimated using a vehicle detector together with a multiperspective optimized tracker in each view. The trajectories are transformed to a common ground plane, where they are associated between perspectives and analyzed to reveal tendencies around the ego-vehicle. The system is tested on sequences from 2.5 h...

Control Of Motor Unit Firing During Step-Like Increases In Voluntary Force

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Xiaogang eHu

2014-09-01

Full Text Available In most skeletal muscles, force is generated by a combination of motor unit (MU recruitment and increases in the firing rate of previously active MUs. Two contrasting patterns of firing rate organization have been reported. In the first pattern, the earliest recruited MUs reach the highest firing rates as force is increased, and later recruited MUs fire at lower rates. When firing rate of multiple MUs are superimposed, these rate trajectories form a concentric layered profile termed ‘onion skin’. In the second pattern, called ‘reverse onion skin’, later recruited MUs reach higher firing rates, and crossing of firing rate trajectories for recorded MUs is common (although such trajectories are assembled routinely from different trials. Our present study examined the firing rate organization of concurrently active MUs of the first dorsal interosseous muscle during serial, step-like increases in isometric abduction forces. We used a surface sensor array coupled with MU discrimination algorithms to characterize MU firing patterns. Our objective was to determine whether ‘onion skin’ profiles are contingent upon the force trajectory of the motor task, examined here using step-like increases of force output, and also whether they are manifested at different force levels.Our results revealed that the overall ‘onion skin’ firing rate profile was retained as the force level increased with each force step up to 15% MVC. However, the distribution of firing rates across MUs was compressed with increasing force, and overlapping firing rate of units were observed. This rate compression was largely due to rate saturation of the relatively high frequency discharging MUs.Our results reflect flexible firing patterns across MUs at different levels of excitation drive. It is also evident that many units did not follow all the step increases consistently. This failure to track firing rate increases at higher forces could be due to an intrinsically

Adaptation of manipulation skills in physical contact with the environment to reference force profiles

DEFF Research Database (Denmark)

Abu-Dakka, Fares J.; Nemec, Bojan; Jørgensen, Jimmy A.

2015-01-01

We propose a new methodology for learning and adaption of manipulation skills that involve physical contact with the environment. Pure position control is unsuitable for such tasks because even small errors in the desired trajectory can cause significant deviations from the desired forces...... and torques. The proposed algorithm takes a reference Cartesian trajectory and force/torque profile as input and adapts the movement so that the resulting forces and torques match the reference profiles. The learning algorithm is based on dynamic movement primitives and quaternion representation...

Changes in At-Risk American Men's Crime and Substance Use Trajectories following Fatherhood

Science.gov (United States)

Kerr, David C. R.; Capaldi, Deborah M.; Owen, Lee D.; Wiesner, Margit; Pears, Katherine C.

2011-01-01

Fatherhood can be a turning point in development and in men's crime and substance use trajectories. At-risk boys (N = 206) were assessed annually from ages 12 to 31 years. Crime, arrest, and tobacco, alcohol, and marijuana use trajectories were examined. Marriage was associated with lower levels of crime and less frequent substance use. Following…

Multi-scale window specification over streaming trajectories

Directory of Open Access Journals (Sweden)

Kostas Patroumpas

2013-12-01

Full Text Available Enormous amounts of positional information are collected by monitoring applications in domains such as fleet management, cargo transport, wildlife protection, etc. With the advent of modern location-based services, processing such data mostly focuses on providing real-time response to a variety of user requests in continuous and scalable fashion. An important class of such queries concerns evolving trajectories that continuously trace the streaming locations of moving objects, like GPS-equipped vehicles, commodities with RFID's, people with smartphones etc. In this work, we propose an advanced windowing operator that enables online, incremental examination of recent motion paths at multiple resolutions for numerous point entities. When applied against incoming positions, this window can abstract trajectories at coarser representations towards the past, while retaining progressively finer features closer to the present. We explain the semantics of such multi-scale sliding windows through parameterized functions that reflect the sequential nature of trajectories and can effectively capture their spatiotemporal properties. Such window specification goes beyond its usual role for non-blocking processing of multiple concurrent queries. Actually, it can offer concrete subsequences from each trajectory, thus preserving continuity in time and contiguity in space along the respective segments. Further, we suggest language extensions in order to express characteristic spatiotemporal queries using windows. Finally, we discuss algorithms for nested maintenance of multi-scale windows and evaluate their efficiency against streaming positional data, offering empirical evidence of their benefits to online trajectory processing.

Comparison of measured and computed radial trajectories of plasma focus devices UMDPF1 and UMDPF0

Energy Technology Data Exchange (ETDEWEB)

Lim, L. H.; Yap, S. L., E-mail: yapsl@um.edu.my; Lim, L. K.; Lee, M. C.; Poh, H. S.; Ma, J. [Plasma Technology Research Centre, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Yap, S. S. [UMPEDAC, University of Malaya, 50603 Kuala Lumpur (Malaysia); Faculty of Engineering, Multimedia University, Cyberjaya, 63100 Selangor (Malaysia); Lee, S. [Plasma Technology Research Centre, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); INTI International University, 71800 Nilai (Malaysia); Institute for Plasma Focus Studies, 32 Oakpark Drive, Chadstone 3148 (Australia)

2015-09-15

In published literature, there has been scant data on radial trajectory of the plasma focus and no comparison of computed with measured radial trajectory. This paper provides the first such comparative study. We compute the trajectories of the inward-moving radial shock and magnetic piston of UMDPF1 plasma focus and compare these with measured data taken from a streak photograph. The comparison shows agreement with the measured radial trajectory in terms of average speeds and general shape of trajectory. This paper also presents the measured trajectory of the radially compressing piston in another machine, the UMDPF0 plasma focus, confirming that the computed radial trajectory also shows similar general agreement. Features of divergence between the computed and measured trajectories, towards the end of the radial compression, are discussed. From the measured radial trajectories, an inference is made that the neutron yield mechanism could not be thermonuclear. A second inference is made regarding the speeds of axial post-pinch shocks, which are recently considered as a useful tool for damage testing of fusion-related wall materials.

Forced sound transmission through a finite-sized single leaf panel subject to a point source excitation.

Science.gov (United States)

Wang, Chong

2018-03-01

In the case of a point source in front of a panel, the wavefront of the incident wave is spherical. This paper discusses spherical sound waves transmitting through a finite sized panel. The forced sound transmission performance that predominates in the frequency range below the coincidence frequency is the focus. Given the point source located along the centerline of the panel, forced sound transmission coefficient is derived through introducing the sound radiation impedance for spherical incident waves. It is found that in addition to the panel mass, forced sound transmission loss also depends on the distance from the source to the panel as determined by the radiation impedance. Unlike the case of plane incident waves, sound transmission performance of a finite sized panel does not necessarily converge to that of an infinite panel, especially when the source is away from the panel. For practical applications, the normal incidence sound transmission loss expression of plane incident waves can be used if the distance between the source and panel d and the panel surface area S satisfy d/S>0.5. When d/S ≈0.1, the diffuse field sound transmission loss expression may be a good approximation. An empirical expression for d/S=0  is also given.

Trajectory Planning and Walking Pattern Generation of Humanoid Robot Motion

Directory of Open Access Journals (Sweden)

Saeed Abdolshah

2014-12-01

Full Text Available Walking trajectory generation for a humanoid robot is a challenging control  issue. In this paper, a walking cycle has been recognized considering human motion, and nine simple steps were distinguished in a full step of walking which form motion trajectory, and generates a simplified ZMP motion formulation. This system was used in humanoid robot simulation motion and is achievable easily in walking steps of robot. A minimum DOFs humanoid robot has been considered and geometrical relationships between the robot links were presented by the Denavit-Hartenberg method. The inverse kinematics equations have been solved regarding to extracted ZMP trajectory formula, and constraints in different steps. As a result; angular velocity, acceleration and power of motors were obtained using the relationships and Jacobin. At each step, extracted data were applied on simulated robot in Matlab, and Visual Nastran software. Zero moment point trajectory was evaluated in simulation environment.

Estimation Trajectory of the Low-Frequency Floating Car Considering the Traffic Control

Directory of Open Access Journals (Sweden)

Zhijian Wang

2013-01-01

Full Text Available Floating car equipped with GPS to detect traffic flow has been widely used in ITS research and applications. The trajectory estimation is the most critical and complex part in the floating vehicle information processing system. However, the trajectory estimation would be more difficult when using the low-frequency data sampling because of the high communication cost and the numerous data. Specifically, the ordinary algorithm cannot determine the specific vehicle paths with two anchor points across multiple intersections. Considering the accuracy in map matching, this paper used a delay matching algorithm and studied the trajectory estimation algorithm focusing on the issue of existence of a small road network between two anchor points. A method considering the three multiobjective factors of signal control and driving distance and number of intersections was developed. Firstly, an optimal solution set was acquired according to multiobjective decision theory and Pareto optimal principles in game theory. Then, the optimal solution set was evaluated synthetically based on the fuzzy set theory. Finally, the candidate trajectory which is the core evaluation factor was identified as the best possible travel path. The algorithm was validated by using the real traffic data in Wangjing area of Beijing. The results showed that the algorithm can get a better trajectory estimation and provide more traffic information to traffic management department.

Reduced aliasing artifacts using shaking projection k-space sampling trajectory

Science.gov (United States)

Zhu, Yan-Chun; Du, Jiang; Yang, Wen-Chao; Duan, Chai-Jie; Wang, Hao-Yu; Gao, Song; Bao, Shang-Lian

2014-03-01

Radial imaging techniques, such as projection-reconstruction (PR), are used in magnetic resonance imaging (MRI) for dynamic imaging, angiography, and short-T2 imaging. They are less sensitive to flow and motion artifacts, and support fast imaging with short echo times. However, aliasing and streaking artifacts are two main sources which degrade radial imaging quality. For a given fixed number of k-space projections, data distributions along radial and angular directions will influence the level of aliasing and streaking artifacts. Conventional radial k-space sampling trajectory introduces an aliasing artifact at the first principal ring of point spread function (PSF). In this paper, a shaking projection (SP) k-space sampling trajectory was proposed to reduce aliasing artifacts in MR images. SP sampling trajectory shifts the projection alternately along the k-space center, which separates k-space data in the azimuthal direction. Simulations based on conventional and SP sampling trajectories were compared with the same number projections. A significant reduction of aliasing artifacts was observed using the SP sampling trajectory. These two trajectories were also compared with different sampling frequencies. A SP trajectory has the same aliasing character when using half sampling frequency (or half data) for reconstruction. SNR comparisons with different white noise levels show that these two trajectories have the same SNR character. In conclusion, the SP trajectory can reduce the aliasing artifact without decreasing SNR and also provide a way for undersampling reconstruction. Furthermore, this method can be applied to three-dimensional (3D) hybrid or spherical radial k-space sampling for a more efficient reduction of aliasing artifacts.

Reduced aliasing artifacts using shaking projection k-space sampling trajectory

International Nuclear Information System (INIS)

Zhu Yan-Chun; Yang Wen-Chao; Wang Hao-Yu; Gao Song; Bao Shang-Lian; Du Jiang; Duan Chai-Jie

2014-01-01

Radial imaging techniques, such as projection-reconstruction (PR), are used in magnetic resonance imaging (MRI) for dynamic imaging, angiography, and short-T2 imaging. They are less sensitive to flow and motion artifacts, and support fast imaging with short echo times. However, aliasing and streaking artifacts are two main sources which degrade radial imaging quality. For a given fixed number of k-space projections, data distributions along radial and angular directions will influence the level of aliasing and streaking artifacts. Conventional radial k-space sampling trajectory introduces an aliasing artifact at the first principal ring of point spread function (PSF). In this paper, a shaking projection (SP) k-space sampling trajectory was proposed to reduce aliasing artifacts in MR images. SP sampling trajectory shifts the projection alternately along the k-space center, which separates k-space data in the azimuthal direction. Simulations based on conventional and SP sampling trajectories were compared with the same number projections. A significant reduction of aliasing artifacts was observed using the SP sampling trajectory. These two trajectories were also compared with different sampling frequencies. A SP trajectory has the same aliasing character when using half sampling frequency (or half data) for reconstruction. SNR comparisons with different white noise levels show that these two trajectories have the same SNR character. In conclusion, the SP trajectory can reduce the aliasing artifact without decreasing SNR and also provide a way for undersampling reconstruction. Furthermore, this method can be applied to three-dimensional (3D) hybrid or spherical radial k-space sampling for a more efficient reduction of aliasing artifacts

Trajectory generation for an on-road autonomous vehicle

Science.gov (United States)

Horst, John; Barbera, Anthony

2006-05-01

We describe an algorithm that generates a smooth trajectory (position, velocity, and acceleration at uniformly sampled instants of time) for a car-like vehicle autonomously navigating within the constraints of lanes in a road. The technique models both vehicle paths and lane segments as straight line segments and circular arcs for mathematical simplicity and elegance, which we contrast with cubic spline approaches. We develop the path in an idealized space, warp the path into real space and compute path length, generate a one-dimensional trajectory along the path length that achieves target speeds and positions, and finally, warp, translate, and rotate the one-dimensional trajectory points onto the path in real space. The algorithm moves a vehicle in lane safely and efficiently within speed and acceleration maximums. The algorithm functions in the context of other autonomous driving functions within a carefully designed vehicle control hierarchy.

The effective QCD phase diagram and the critical end point

Directory of Open Access Journals (Sweden)

Alejandro Ayala

2015-08-01

Full Text Available We study the QCD phase diagram on the temperature T and quark chemical potential μ plane, modeling the strong interactions with the linear sigma model coupled to quarks. The phase transition line is found from the effective potential at finite T and μ taking into account the plasma screening effects. We find the location of the critical end point (CEP to be (μCEP/Tc,TCEP/Tc∼(1.2,0.8, where Tc is the (pseudocritical temperature for the crossover phase transition at vanishing μ. This location lies within the region found by lattice inspired calculations. The results show that in the linear sigma model, the CEP's location in the phase diagram is expectedly determined solely through chiral symmetry breaking. The same is likely to be true for all other models which do not exhibit confinement, provided the proper treatment of the plasma infrared properties for the description of chiral symmetry restoration is implemented. Similarly, we also expect these corrections to be substantially relevant in the QCD phase diagram.

The Newtonian force experienced by a point mass near a finite cylindrical source

International Nuclear Information System (INIS)

Selvaggi, Jerry P; Salon, Sheppard; Chari, M V K

2008-01-01

The Newtonian gravitational force experienced by a point mass located at some external point from a thick-walled, hollow and uniform finite circular cylindrical body was recently solved by Lockerbie, Veryaskin and Xu (1993 Class. Quantum Grav. 10 2419). Their method of attack relied on the introduction of the circular cylindrical free-space Green function representation for the inverse distance which appears in the formulation of the Newtonian potential function. This ultimately leads Lockerbie et al to a final expression for the Newtonian potential function which is expressed as a double summation of even-ordered Legendre polynomials. However, the kernel of the cylindrical free-space Green function which is represented by an infinite integral of the product of two Bessel functions and a decaying exponential can be analytically evaluated in terms of a toroidal function. This leads to a simplification in the mathematical analysis developed by Lockerbie et al. Also, each term in the infinite series solution for the Newtonian potential function can be expressed in closed form in terms of elementary functions. The authors develop the Newtonian potential function by employing toroidal functions of zeroth order or Legendre functions of half-integral degree, Q m-1/2 (β)(Bouwkamp and de Bruijn 1947 J. Appl. Phys.18 562, Cohl et al 2001 Phys. Rev.A 64 052509-1, Selvaggi et al 2004 IEEE Trans. Magn.40 3278). These functions are monotonically decreasing and converge rapidly (Moon and Spencer 1961 Field Theory for Engineers (New Jersey: Van Nostrand Company) pp 368-76, Cohl and Tohline 1999 Astrophys. J.527 86). The introduction of the toroidal harmonic expansion leads to an infinite series solution for which each term can be expressed as an elementary function. This enables one to easily compute the axial and radial forces experienced by an internal or an external point mass

Reproductive and relational trajectories leading to pregnancy: Differences between adolescents and adult women who had an abortion.

Science.gov (United States)

Pereira, Joana I F; Pires, Raquel S A; Araújo-Pedrosa, Anabela F; Canavarro, Maria Cristina C S P

2018-05-01

The literature has been conceptualizing pregnancy occurrence as a multiphase event. However, the different combinations of decisions and behaviors leading to pregnancy that end in abortion remain unexplored in the literature. The aims of the study were to describe the reproductive and relational trajectories leading to pregnancy in women who decide to abort and to explore the differences in this process according to women's age [adolescents (leading to pregnancy were identified. The most frequent trajectory (30.8%) included women who 1) were involved in a long-term romantic relationship, 2) did not plan the pregnancy, 3) were using contraception, and 4) did not identify the contraceptive failure that led to pregnancy. Although this was the most frequent trajectory for both age groups, the remaining trajectories showed a different distribution. Compared to adolescents, adult women's trajectories more frequently included casual relationships with non-use of contraception, or contraceptive use with no contraceptive failure identification. Our study highlights the need to recognize the multiplicity of reproductive and relational trajectories leading to pregnancies that end in abortion and their specificities according to women's age. These findings have important implications for abortion counselling and for the development of age-appropriate guidelines for preventive interventions, by drawing attention to prioritization of different contexts of intervention according women's age. Copyright © 2018 Elsevier B.V. All rights reserved.

Supervised Learning Applied to Air Traffic Trajectory Classification

Science.gov (United States)

Bosson, Christabelle; Nikoleris, Tasos

2018-01-01

Given the recent increase of interest in introducing new vehicle types and missions into the National Airspace System, a transition towards a more autonomous air traffic control system is required in order to enable and handle increased density and complexity. This paper presents an exploratory effort of the needed autonomous capabilities by exploring supervised learning techniques in the context of aircraft trajectories. In particular, it focuses on the application of machine learning algorithms and neural network models to a runway recognition trajectory-classification study. It investigates the applicability and effectiveness of various classifiers using datasets containing trajectory records for a month of air traffic. A feature importance and sensitivity analysis are conducted to challenge the chosen time-based datasets and the ten selected features. The study demonstrates that classification accuracy levels of 90% and above can be reached in less than 40 seconds of training for most machine learning classifiers when one track data point, described by the ten selected features at a particular time step, per trajectory is used as input. It also shows that neural network models can achieve similar accuracy levels but at higher training time costs.

Polarization extinction ratio of the polarization crosstalk caused by point pressure force in the polarization-maintaining fiber

Science.gov (United States)

Mukhtubayev, Azamat B.; Aksarin, Stanislav M.; Strigalev, Vladimir E.

2017-11-01

A study of the orthogonal polarization modes crosstalk changes in the point of different mechanical actions (pressure force) in the polarization-maintaining fiber with straining elliptical cladding is presented. It was found that by increasing of the pressure force the polarization extinction ratio increases nonlinearly. Also revealed the dependence of the extinction coefficient and the angle between vector of the mechanical action and polarization axes of the test fiber, which leads to change the extinction coefficient variable from -57 dB to -25 dB under the pressure force of 0.7 N. Also it was found that the cross angle of the fiber axes doesn't influence on the extinction ratio value of the mechanical induced polarization crosstalk.

Cognitive loading affects motor awareness and movement kinematics but not locomotor trajectories during goal-directed walking in a virtual reality environment.

Science.gov (United States)

Kannape, Oliver Alan; Barré, Arnaud; Aminian, Kamiar; Blanke, Olaf

2014-01-01

The primary purpose of this study was to investigate the effects of cognitive loading on movement kinematics and trajectory formation during goal-directed walking in a virtual reality (VR) environment. The secondary objective was to measure how participants corrected their trajectories for perturbed feedback and how participants' awareness of such perturbations changed under cognitive loading. We asked 14 healthy young adults to walk towards four different target locations in a VR environment while their movements were tracked and played back in real-time on a large projection screen. In 75% of all trials we introduced angular deviations of ±5° to ±30° between the veridical walking trajectory and the visual feedback. Participants performed a second experimental block under cognitive load (serial-7 subtraction, counter-balanced across participants). We measured walking kinematics (joint-angles, velocity profiles) and motor performance (end-point-compensation, trajectory-deviations). Motor awareness was determined by asking participants to rate the veracity of the feedback after every trial. In-line with previous findings in natural settings, participants displayed stereotypical walking trajectories in a VR environment. Our results extend these findings as they demonstrate that taxing cognitive resources did not affect trajectory formation and deviations although it interfered with the participants' movement kinematics, in particular walking velocity. Additionally, we report that motor awareness was selectively impaired by the secondary task in trials with high perceptual uncertainty. Compared with data on eye and arm movements our findings lend support to the hypothesis that the central nervous system (CNS) uses common mechanisms to govern goal-directed movements, including locomotion. We discuss our results with respect to the use of VR methods in gait control and rehabilitation.

Casimir Energy of the Nambu-Goto String with Gauss-Bonnet Term and Point-Like Masses at the Ends

Science.gov (United States)

Hadasz, Leszek

1999-09-01

We calculate the Casimir energy of the rotating Nambu-Goto string with the Gauss-Bonnet term in the action and point-like masses at the ends. This energy turns out to be negative for every values of the parameters of the model.

Casimir Energy of the Nambu-Goto String with Gauss-Bonnet Term and Point-Like Masses at the Ends

International Nuclear Information System (INIS)

Hadasz, L.

1999-01-01

We calculate the Casimir energy of the rotating Nambu-Goto string with the Gauss-Bonnet term in the action and point-like masses at the ends. This energy turns out to be negative for every values of the parameters of the model. (author)

Sampling Based Trajectory Planning for Robots in Dynamic Human Environments

DEFF Research Database (Denmark)

Svenstrup, Mikael

2010-01-01

Open-ended human environments, such as pedestrian streets, hospital corridors, train stations etc., are places where robots start to emerge. Hence, being able to plan safe and natural trajectories in these dynamic environments is an important skill for future generations of robots. In this work...... the problem is formulated as planning a minimal cost trajectory through a potential field, defined from the perceived position and motion of persons in the environment. A modified Rapidlyexploring Random Tree (RRT) algorithm is proposed as a solution to the planning problem. The algorithm implements a new...... for the uncertainty in the dynamic environment. The planning algorithm is demonstrated in a simulated pedestrian street environment....

Development and Implementation of an End-Effector Upper Limb Rehabilitation Robot for Hemiplegic Patients with Line and Circle Tracking Training

Directory of Open Access Journals (Sweden)

Yali Liu

2017-01-01

Full Text Available Numerous robots have been widely used to deliver rehabilitative training for hemiplegic patients to improve their functional ability. Because of the complexity and diversity of upper limb motion, customization of training patterns is one key factor during upper limb rehabilitation training. Most of the current rehabilitation robots cannot intelligently provide adaptive training parameters, and they have not been widely used in clinical rehabilitation. This article proposes a new end-effector upper limb rehabilitation robot, which is a two-link robotic arm with two active degrees of freedom. This work investigated the kinematics and dynamics of the robot system, the control system, and the realization of different rehabilitation therapies. We also explored the influence of constraint in rehabilitation therapies on interaction force and muscle activation. The deviation of the trajectory of the end effector and the required trajectory was less than 1 mm during the tasks, which demonstrated the movement accuracy of the robot. Besides, results also demonstrated the constraint exerted by the robot provided benefits for hemiplegic patients by changing muscle activation in the way similar to the movement pattern of the healthy subjects, which indicated that the robot can improve the patient’s functional ability by training the normal movement pattern.

Periodic trajectories for a two-dimensional nonintegrable Hamiltonian

International Nuclear Information System (INIS)

Baranger, M.; Davies, K.T.R.

1987-01-01

A numerical study is made of the classical periodic trajectories for the two-dimensional nonintegrable Hamiltonian H = 1/2(p 2 /sub x/+p 2 /sub y/)+(y-1/2x 2 ) 2 +0.05 x 2 . In addition to x--y pictures of the trajectories, E--tau (energy--period) plots of the periodic families are presented. Efforts have been ade to include all trajectories with short periods and all simple branchings of these trajectories. The monodromy matrix has been calculated in all cases, and from it the stability properties are derived. The topology of the E--tau plot has been explored, with the following results. One family may have several stable regions. The plot is not completely connected; there are islands. The plot is not a tree; there are cycles. There are isochronous branchings, period-doublings, and period-multiplyings of higher orders, and examples of each of these are presented. There is often more than one branch issuing from a branch point. Some general empirical rules are inferred. In particular, the existence of isochronous branching is seen to be a consequence of the symmetry of the Hamiltonian. All these results agree with the general classification of possible branchings derived in Ref. [10]. (M. A. M. de Aguiar, C. P. Malta, M. Baranger, and K. T. R. Davies, in preparation). Finally, some nonperiodic trajectories are calculated to illustrate the fact that stable periodic trajectories lie in ''regular'' regions of phase space, while unstable ones lie in ''chaotic'' regions

Learning Points and Routes to Recommend Trajectories

OpenAIRE

Chen, Dawei; Ong, Cheng Soon; Xie, Lexing

2016-01-01

The problem of recommending tours to travellers is an important and broadly studied area. Suggested solutions include various approaches of points-of-interest (POI) recommendation and route planning. We consider the task of recommending a sequence of POIs, that simultaneously uses information about POIs and routes. Our approach unifies the treatment of various sources of information by representing them as features in machine learning algorithms, enabling us to learn from past behaviour. Info...

Centrifugal force: a few surprises

International Nuclear Information System (INIS)

Abramowicz, M.A.; Max-Planck-Institut fuer Physik und Astrophysik, Garching

1990-01-01

The need for a rather fundamental revision in understanding of the nature of the centrifugal force is discussed. It is shown that in general relativity (and contrary to the situation in Newtonian theory) rotation of a reference frame is a necessary but not sufficient condition for the centrifugal force to appear. A sufficient condition for its appearance, in the instantaneously corotating reference frame of a particle, is that the particle motion in space (observed in the global rest frame) differs from a photon trajectory. The direction of the force is the same as that of the gradient of the effective potential for photon motion. In some cases, the centrifugal force will attract towards the axis of rotation. (author)

A Novel Approach to Identifying Trajectories of Mobility Change in Older Adults.

Directory of Open Access Journals (Sweden)

Rachel E Ward

Full Text Available To validate trajectories of late-life mobility change using a novel approach designed to overcome the constraints of modest sample size and few follow-up time points.Using clinical reasoning and distribution-based methodology, we identified trajectories of mobility change (Late Life Function and Disability Instrument across 2 years in 391 participants age ≥65 years from a prospective cohort study designed to identify modifiable impairments predictive of mobility in late-life. We validated our approach using model fit indices and comparing baseline mobility-related factors between trajectories.Model fit indices confirmed that the optimal number of trajectories were between 4 and 6. Mobility-related factors varied across trajectories with the most unfavorable values in poor mobility trajectories and the most favorable in high mobility trajectories. These factors included leg strength, trunk extension endurance, knee flexion range of motion, limb velocity, physical performance measures, and the number and prevalence of medical conditions including osteoarthritis and back pain.Our findings support the validity of this approach and may facilitate the investigation of a broader scope of research questions within aging populations of varied sizes and traits.

On Choosing a Rational Flight Trajectory to the Moon

Science.gov (United States)

Gordienko, E. S.; Khudorozhkov, P. A.

2017-12-01

The algorithm for choosing a trajectory of spacecraft flight to the Moon is discussed. The characteristic velocity values needed for correcting the flight trajectory and a braking maneuver are estimated using the Monte Carlo method. The profile of insertion and flight to a near-circular polar orbit with an altitude of 100 km of an artificial lunar satellite (ALS) is given. The case of two corrections applied during the flight and braking phases is considered. The flight to an ALS orbit is modeled in the geocentric geoequatorial nonrotating coordinate system with the influence of perturbations from the Earth, the Sun, and the Moon factored in. The characteristic correction costs corresponding to corrections performed at different time points are examined. Insertion phase errors, the errors of performing the needed corrections, and the errors of determining the flight trajectory parameters are taken into account.

Overview of the "epigenetic end points in toxicologic pathology and relevance to human health" session of the 2014 Society Of Toxicologic Pathology Annual Symposium.

Science.gov (United States)

Hoenerhoff, Mark J; Hartke, James

2015-01-01

The theme of the Society of Toxicologic Pathology 2014 Annual Symposium was "Translational Pathology: Relevance of Toxicologic Pathology to Human Health." The 5th session focused on epigenetic end points in biology, toxicity, and carcinogenicity, and how those end points are relevant to human exposures. This overview highlights the various presentations in this session, discussing integration of epigenetics end points in toxicologic pathology studies, investigating the role of epigenetics in product safety assessment, epigenetic changes in cancers, methodologies to detect them, and potential therapies, chromatin remodeling in development and disease, and epigenomics and the microbiome. The purpose of this overview is to discuss the application of epigenetics to toxicologic pathology and its utility in preclinical or mechanistic based safety, efficacy, and carcinogenicity studies. © 2014 by The Author(s).

Long range trajectories

Energy Technology Data Exchange (ETDEWEB)

Allen, P. W.; Jessup, E. A.; White, R. E. [Air Resources Field Research Office, Las Vegas, Nevada (United States)

1967-07-01

A single air molecule can have a trajectory that can be described with a line, but most meteorologists use single lines to represent the trajectories of air parcels. A single line trajectory has the disadvantage that it is a categorical description of position. Like categorized forecasts it provides no qualification, and no provision for dispersion in case the parcel contains two or more molecules which may take vastly different paths. Diffusion technology has amply demonstrated that an initial aerosol cloud or volume of gas in the atmosphere not only grows larger, but sometimes divides into puffs, each having a different path or swath. Yet, the average meteorologist, faced with the problem of predicting the future motion of a cloud, usually falls back on the line trajectory approach with the explanation that he had no better tool for long range application. In his more rational moments, he may use some arbitrary device to spread his cloud with distance. One such technique has been to separate the trajectory into two or more trajectories, spaced about the endpoint of the original trajectory after a short period of travel, repeating this every so often like a chain reaction. This has the obvious disadvantage of involving a large amount of labor without much assurance of improved accuracy. Another approach is to draw a circle about the trajectory endpoint, to represent either diffusion or error. The problem then is to know what radius to give the circle and also whether to call it diffusion or error. Meteorologists at the Nevada Test Site (NTS) are asked frequently to provide advice which involves trajectory technology, such as prediction of an aerosol cloud path, reconstruction of the motion of a volume of air, indication of the dilution, and the possible trajectory prediction error over great distances. Therefore, we set out, nearly three years ago, to provide some statistical knowledge about the status of our trajectory technology. This report contains some of the

Origin of chaos near critical points of quantum flow.

Science.gov (United States)

Efthymiopoulos, C; Kalapotharakos, C; Contopoulos, G

2009-03-01

The general theory of motion in the vicinity of a moving quantum nodal point (vortex) is studied in the framework of the de Broglie-Bohm trajectory method of quantum mechanics. Using an adiabatic approximation, we find that near any nodal point of an arbitrary wave function psi there is an unstable point (called the X point) in a frame of reference moving with the nodal point. The local phase portrait forms always a characteristic pattern called the "nodal-point- X -point complex." We find general formulas for this complex as well as necessary and sufficient conditions of validity of the adiabatic approximation. We demonstrate that chaos emerges from the consecutive scattering events of the orbits with nodal-point- X -point complexes. The scattering events are of two types (called type I and type II). A theoretical model is constructed yielding the local value of the Lyapunov characteristic numbers in scattering events of both types. The local Lyapunov characteristic number scales as an inverse power of the speed of the nodal point in the rest frame, implying that it scales proportionally to the size of the nodal-point- X -point complex. It is also an inverse power of the distance of a trajectory from the X point's stable manifold far from the complex. This distance plays the role of an effective "impact parameter." The results of detailed numerical experiments with different wave functions, possessing one, two, or three moving nodal points, are reported. Examples are given of regular and chaotic trajectories, and the statistics of the Lyapunov characteristic numbers of the orbits are found and compared to the number of encounter events of each orbit with the nodal-point- X -point complexes. The numerical results are in agreement with the theory, and various phenomena appearing at first as counterintuitive find a straightforward explanation.

No significant effect of angiotensin II receptor blockade on intermediate cardiovascular end points in hemodialysis patients

DEFF Research Database (Denmark)

Peters, Christian Daugaard; Kjaergaard, Krista D; Jensen, Jens D

2014-01-01

Agents blocking the renin-angiotensin-aldosterone system are frequently used in patients with end-stage renal disease, but whether they exert beneficial cardiovascular effects is unclear. Here the long-term effects of the angiotensin II receptor blocker, irbesartan, were studied in hemodialysis......, and residual renal function. Brachial blood pressure decreased significantly in both groups, but there was no significant difference between placebo and irbesartan. Use of additional antihypertensive medication, ultrafiltration volume, and dialysis dosage were not different. Intermediate cardiovascular end...... points such as central aortic blood pressure, carotid-femoral pulse wave velocity, left ventricular mass index, N-terminal brain natriuretic prohormone, heart rate variability, and plasma catecholamines were not significantly affected by irbesartan treatment. Changes in systolic blood pressure during...

Casimir energy of the Nambu-Goto string with Gauss-Bonnet term and point-like masses at the ends

OpenAIRE

Hadasz, Leszek

1999-01-01

We calculate (using zeta function regularization) the Casimir energy of the rotating Nambu-Goto string with the Gauss-Bonnet term in the action and point-like masses at the ends. The resulting value turns out to be negative for all values of the parameters of the model.

Understanding interference experiments with polarized light through photon trajectories

International Nuclear Information System (INIS)

Sanz, A.S.; Davidovic, M.; Bozic, M.; Miret-Artes, S.

2010-01-01

Bohmian mechanics allows to visualize and understand the quantum-mechanical behavior of massive particles in terms of trajectories. As shown by Bialynicki-Birula, Electromagnetism also admits a hydrodynamical formulation when the existence of a wave function for photons (properly defined) is assumed. This formulation thus provides an alternative interpretation of optical phenomena in terms of photon trajectories, whose flow yields a pictorial view of the evolution of the electromagnetic energy density in configuration space. This trajectory-based theoretical framework is considered here to study and analyze the outcome from Young-type diffraction experiments within the context of the Arago-Fresnel laws. More specifically, photon trajectories in the region behind the two slits are obtained in the case where the slits are illuminated by a polarized monochromatic plane wave. Expressions to determine electromagnetic energy flow lines and photon trajectories within this scenario are provided, as well as a procedure to compute them in the particular case of gratings totally transparent inside the slits and completely absorbing outside them. As is shown, the electromagnetic energy flow lines obtained allow to monitor at each point of space the behavior of the electromagnetic energy flow and, therefore, to evaluate the effects caused on it by the presence (right behind each slit) of polarizers with the same or different polarization axes. This leads to a trajectory-based picture of the Arago-Fresnel laws for the interference of polarized light.

Lack of Bystander Effects From High-LET Radiation For Early Cytogenetic End Points

International Nuclear Information System (INIS)

Groesser, Torsten; Cooper, Brian; Rydberg, Bjorn

2008-01-01

The aim of this work was to study radiation-induced bystander effects for early cytogenetic end points in various cell lines using the medium transfer technique after exposure to high- and low-LET radiation. Cells were exposed to 20 MeV/ nucleon nitrogen ions, 968 MeV/nucleon iron ions, or 575 MeV/nucleon iron ions followed by transfer of the conditioned medium from the irradiated cells to unirradiated test cells. The effects studied included DNA double-strand break induction, γ-H2AX focus formation, induction of chromatid breaks in prematurely condensed chromosomes, and micronucleus formation using DNA repair-proficient and -deficient hamster and human cell lines (xrs6, V79, SW48, MO59K and MO59J). Cell survival was also measured in SW48 bystander cells using X rays. Although it was occasionally possible to detect an increase in chromatid break levels using nitrogen ions and to see a higher number of γ-H2AX foci using nitrogen and iron ions in xrs6 bystander cells in single experiments, the results were not reproducible. After we pooled all the data, we could not verify a significant bystander effect for any of these end points. Also, we did not detect a significant bystander effect for DSB induction or micronucleus formation in these cell lines or for clonogenic survival in SW48 cells. The data suggest that DNA damage and cytogenetic changes are not induced in bystander cells. In contrast, data in the literature show pronounced bystander effects in a variety of cell lines, including clonogenic survival in SW48 cells and induction of chromatid breaks and micronuclei in hamster cells. To reconcile these conflicting data, it is possible that the epigenetic status of the specific cell line or the precise culture conditions and medium supplements, such as serum, may be critical for inducing bystander effects.

On the analytic and numeric optimisation of airplane trajectories under real atmospheric conditions

Science.gov (United States)

Gonzalo, J.; Domínguez, D.; López, D.

2014-12-01

From the beginning of aviation era, economic constraints have forced operators to continuously improve the planning of the flights. The revenue is proportional to the cost per flight and the airspace occupancy. Many methods, the first started in the middle of last century, have explore analytical, numerical and artificial intelligence resources to reach the optimal flight planning. In parallel, advances in meteorology and communications allow an almost real-time knowledge of the atmospheric conditions and a reliable, error-bounded forecast for the near future. Thus, apart from weather risks to be avoided, airplanes can dynamically adapt their trajectories to minimise their costs. International regulators are aware about these capabilities, so it is reasonable to envisage some changes to allow this dynamic planning negotiation to soon become operational. Moreover, current unmanned airplanes, very popular and often small, suffer the impact of winds and other weather conditions in form of dramatic changes in their performance. The present paper reviews analytic and numeric solutions for typical trajectory planning problems. Analytic methods are those trying to solve the problem using the Pontryagin principle, where influence parameters are added to state variables to form a split condition differential equation problem. The system can be solved numerically -indirect optimisation- or using parameterised functions -direct optimisation-. On the other hand, numerical methods are based on Bellman's dynamic programming (or Dijkstra algorithms), where the fact that two optimal trajectories can be concatenated to form a new optimal one if the joint point is demonstrated to belong to the final optimal solution. There is no a-priori conditions for the best method. Traditionally, analytic has been more employed for continuous problems whereas numeric for discrete ones. In the current problem, airplane behaviour is defined by continuous equations, while wind fields are given in a

Trajectory Based Traffic Analysis

DEFF Research Database (Denmark)

Krogh, Benjamin Bjerre; Andersen, Ove; Lewis-Kelham, Edwin

2013-01-01

We present the INTRA system for interactive path-based traffic analysis. The analyses are developed in collaboration with traffic researchers and provide novel insights into conditions such as congestion, travel-time, choice of route, and traffic-flow. INTRA supports interactive point-and-click a......We present the INTRA system for interactive path-based traffic analysis. The analyses are developed in collaboration with traffic researchers and provide novel insights into conditions such as congestion, travel-time, choice of route, and traffic-flow. INTRA supports interactive point......-and-click analysis, due to a novel and efficient indexing structure. With the web-site daisy.aau.dk/its/spqdemo/we will demonstrate several analyses, using a very large real-world data set consisting of 1.9 billion GPS records (1.5 million trajectories) recorded from more than 13000 vehicles, and touching most...

Trajectory Browser Website

Science.gov (United States)

Foster, Cyrus; Jaroux, Belgacem A.

2012-01-01

The Trajectory Browser is a web-based tool developed at the NASA Ames Research Center to be used for the preliminary assessment of trajectories to small-bodies and planets and for providing relevant launch date, time-of-flight and V requirements. The site hosts a database of transfer trajectories from Earth to asteroids and planets for various types of missions such as rendezvous, sample return or flybys. A search engine allows the user to find trajectories meeting desired constraints on the launch window, mission duration and delta V capability, while a trajectory viewer tool allows the visualization of the heliocentric trajectory and the detailed mission itinerary. The anticipated user base of this tool consists primarily of scientists and engineers designing interplanetary missions in the context of pre-phase A studies, particularly for performing accessibility surveys to large populations of small-bodies. The educational potential of the website is also recognized for academia and the public with regards to trajectory design, a field that has generally been poorly understood by the public. The website is currently hosted on NASA-internal URL http://trajbrowser.arc.nasa.gov/ with plans for a public release as soon as development is complete.

Wave trajectory and electron cyclotron heating in toroidal plasmas

International Nuclear Information System (INIS)

Maekawa, T.; Tanaka, S.; Terumichi, Y.; Hamada, Y.

1977-12-01

Wave trajectories propagating obliquely to magnetic field in toroidal plasmas are studied theoretically. Results show that the ordinary wave at appropriate incident angle is mode-converted to the extraordinary wave at first turning point and is further converted to the electron Bernstein wave during passing a loop or a hooked nail curve near second turning point and is cyclotron-damped away, resulting in local electron heating, before arriving at cyclotron resonance layer. (auth.)

Manifold dynamics in the Earth-Moon system via isomorphic mapping with application to spacecraft end-of-life strategies

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Pontani, Mauro; Giancotti, Marco; Teofilatto, Paolo

2014-12-01

Recently, manifold dynamics has assumed an increasing relevance for analysis and design of low-energy missions, both in the Earth-Moon system and in alternative multibody environments. With regard to lunar missions, exterior and interior transfers, based on the transit through the regions where the collinear libration points L1 and L2 are located, have been studied for a long time and some space missions have already taken advantage of the results of these studies. This paper is focused on the definition and use of a special isomorphic mapping for low-energy mission analysis. A convenient set of cylindrical coordinates is employed to describe the spacecraft dynamics (i.e. position and velocity), in the context of the circular restricted three-body problem, used to model the spacecraft motion in the Earth-Moon system. This isomorphic mapping of trajectories allows the identification and intuitive representation of periodic orbits and of the related invariant manifolds, which correspond to tubes that emanate from the curve associated with the periodic orbit. Heteroclinic connections, i.e. the trajectories that belong to both the stable and the unstable manifolds of two distinct periodic orbits, can be easily detected by means of this representation. This paper illustrates the use of isomorphic mapping for finding (a) periodic orbits, (b) heteroclinic connections between trajectories emanating from two Lyapunov orbits, the first at L1, and the second at L2, and (c) heteroclinic connections between trajectories emanating from the Lyapunov orbit at L1 and from a particular unstable lunar orbit. Heteroclinic trajectories are asymptotic trajectories that travels at zero-propellant cost. In practical situations, a modest delta-v budget is required to perform transfers along the manifolds. This circumstance implies the possibility of performing complex missions, by combining different types of trajectory arcs belonging to the manifolds. This work studies also the possible

Trajectories of marital, parent-child, and sibling conflict during pediatric cancer treatment.

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Katz, Lynn Fainsilber; Fladeboe, Kaitlyn; Lavi, Iris; King, Kevin; Kawamura, Joy; Friedman, Debra; Compas, Bruce; Breiger, David; Lengua, Liliana; Gurtovenko, Kyrill; Stettler, Nicole

2018-05-28

The stress of having a child with cancer can impact the quality of relationships within the family. The current study describes the longitudinal trajectory of marital, parent-child, and sibling conflict beginning around the time of diagnosis through the first year of treatment. We examined the average level of marital, parent-child, and sibling conflict at each monthly time point in the first year of treatment; the proportion of families that fall into the distressed range of marital, parent-child, and sibling conflict at each time point; the typical trajectory of conflict during the first year of treatment and whether there are differences in trajectories across families. A total of 160 families of children newly diagnosed with cancer (Mage = 5.6 years; range = 2-18 years) participated in a short-term prospective longitudinal study. Primary caregivers provided monthly reports of marital, parent-child, and sibling conflict. Using multilevel modeling (MLM), most families showed stability in quality of family relationships, although considerable between-family variability was observed. For married couples, 25-36% of couples were in the distressed range at one time point over the first year of treatment. For married couples, more distress occurred at earlier months, particularly month 3. For parent-child and sibling dyads, the most difficult time periods were during later months. Implications for development of interventions that target at-risk family relationships are discussed. Identifying processes that predict between-family variability in trajectories of family relationships is an important next step, particularly for the marital relationship. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Numerical optimization of actuator trajectories for ITER hybrid scenario profile evolution

International Nuclear Information System (INIS)

Dongen, J van; Hogeweij, G M D; Felici, F; Geelen, P; Maljaars, E

2014-01-01

Optimal actuator trajectories for an ITER hybrid scenario ramp-up are computed using a numerical optimization method. For both L-mode and H-mode scenarios, the time trajectory of plasma current, EC heating and current drive distribution is determined that minimizes a chosen cost function, while satisfying constraints. The cost function is formulated to reflect two desired properties of the plasma q profile at the end of the ramp-up. The first objective is to maximize the ITG turbulence threshold by maximizing the volume-averaged s/q ratio. The second objective is to achieve a stationary q profile by having a flat loop voltage profile. Actuator and physics-derived constraints are included, imposing limits on plasma current, ramp rates, internal inductance and q profile. This numerical method uses the fast control-oriented plasma profile evolution code RAPTOR, which is successfully benchmarked against more complete CRONOS simulations for L-mode and H-mode mode ITER hybrid scenarios. It is shown that the optimized trajectories computed using RAPTOR also result in an improved ramp-up scenario for CRONOS simulations using the same input trajectories. Furthermore, the optimal trajectories are shown to vary depending on the precise timing of the L–H transition. (paper)

A model for helicopter guidance on spiral trajectories

Science.gov (United States)

Mendenhall, S.; Slater, G. L.

1980-01-01

A point mass model is developed for helicopter guidance on spiral trajectories. A fully coupled set of state equations is developed and perturbation equations suitable for 3-D and 4-D guidance are derived and shown to be amenable to conventional state variable feedback methods. Control variables are chosen to be the magnitude and orientation of the net rotor thrust. Using these variables reference controls for nonlevel accelerating trajectories are easily determined. The effects of constant wind are shown to require significant feedforward correction to some of the reference controls and to the time. Although not easily measured themselves, the controls variables chosen are shown to be easily related to the physical variables available in the cockpit.

Automatic Generation of Complex Spatial Trajectories of the UAV and Synthesis of Control

Directory of Open Access Journals (Sweden)

S. B. Tkachev

2015-01-01

Full Text Available In this paper, we propose a new method and algorithms that allow us to design complex spatial trajectories for an unmanned aerial vehicle (UAV passing through a given sequence of waypoints in the three-dimensional space.The nonlinear six-dimensional model of the UAV center-of-mass motion given in the trajectory frame is used for calculations. The state vector includes the altitude, the along-track deviation, the cross-track position, the velocity, the flight-path angle and the heading angle. The longitudinal and transverse overloads and the angle between the cross overload vector and vertical plane are considered as controls. This angle is often named as the roll angle.The feature of the problem is that both positions at waypoints and additional conditions are given. These conditions determine orientation of the velocity vector at each point (using the flight path angle and the heading angle. We also set either the point-visiting time or the pointvisiting velocity. The full state vector and controls are fixed at the starting waypoint.To construct a spatial trajectory, the concept of inverse dynamics problems is applied, as well as modern results of mathematical control theory of nonlinear dynamical systems. The introduction of new virtual controls allows us to represent the original system as an affine (linear in control system. Then, the designed system is converted into the regular canonical form.When we set flight times between any two waypoints, the corresponding segments of the trajectory are designed using time-dependent polynomials of the fifth degree. These polynomials specify the altitude variation, the variation of the along-track deviation and that of the cross-track position. If the point-visiting times are not fixed, the transition to a new independent variable (the normalized mechanical energy of the system is used. This transition is possible if the energy varies monotonically. In this case, the spatial trajectory is defined as a

Active control of sound transmission through a rectangular panel using point-force actuators and piezoelectric film sensors.

Science.gov (United States)

Sanada, Akira; Higashiyama, Kouji; Tanaka, Nobuo

2015-01-01

This study deals with the active control of sound transmission through a rectangular panel, based on single input, single output feedforward vibration control using point-force actuators and piezoelectric film sensors. It focuses on the phenomenon in which the sound power transmitted through a finite-sized panel drops significantly at some frequencies just below the resonance frequencies of the panel in the low-frequency range as a result of modal coupling cancellation. In a previous study, it was shown that when point-force actuators are located on nodal lines for the frequency at which this phenomenon occurs, a force equivalent to the incident sound wave can act on the panel. In this study, a practical method for sensing volume velocity using a small number of piezoelectric film strips is investigated. It is found that two quadratically shaped piezoelectric film strips, attached at the same nodal lines as those where the actuators were placed, can sense the volume velocity approximately in the low-frequency range. Results of simulations show that combining the proposed actuation method and the sensing method can achieve a practical control effect at low frequencies over a wide frequency range. Finally, experiments are carried out to demonstrate the validity and feasibility of the proposed method.

End-point detection in potentiometric titration by continuous wavelet transform.

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Jakubowska, Małgorzata; Baś, Bogusław; Kubiak, Władysław W

2009-10-15

The aim of this work was construction of the new wavelet function and verification that a continuous wavelet transform with a specially defined dedicated mother wavelet is a useful tool for precise detection of end-point in a potentiometric titration. The proposed algorithm does not require any initial information about the nature or the type of analyte and/or the shape of the titration curve. The signal imperfection, as well as random noise or spikes has no influence on the operation of the procedure. The optimization of the new algorithm was done using simulated curves and next experimental data were considered. In the case of well-shaped and noise-free titration data, the proposed method gives the same accuracy and precision as commonly used algorithms. But, in the case of noisy or badly shaped curves, the presented approach works good (relative error mainly below 2% and coefficients of variability below 5%) while traditional procedures fail. Therefore, the proposed algorithm may be useful in interpretation of the experimental data and also in automation of the typical titration analysis, specially in the case when random noise interfere with analytical signal.

Reference trajectory tracking for a multi-DOF robot arm

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Krasňanský Róbert

2015-12-01

Full Text Available This paper presents the problem of tracking the generated reference trajectory by the simulation model of a multi-DOF robot arm. The kinematic transformation between task space and joint configuration coordinates is nonlinear and configuration dependent. To obtain the solution of the forward kinematics problem, the homogeneous transformation matrix is used. A solution to the inverse kinematics is a vector of joint configuration coordinates calculated using of pseudoinverse Jacobian technique. These coordinates correspond to a set of task space coordinates. The algorithm is presented which uses iterative solution and is simplified by considering stepper motors in robot arm joints. The reference trajectory in Cartesian coordinate system is generated on-line by the signal generator previously developed in MS Excel. Dynamic Data Exchange communication protocol allows sharing data with Matlab-Simulink. These data represent the reference tracking trajectory of the end effector. Matlab-Simulink software is used to calculate the representative joint rotations. The proposed algorithm is demonstrated experimentally on the model of 7-DOF robot arm system.

Characterization of the disruption of neural control strategies for dynamic fingertip forces from attractor reconstruction.

Directory of Open Access Journals (Sweden)

Lorenzo Peppoloni

Full Text Available The Strength-Dexterity (SD test measures the ability of the pulps of the thumb and index finger to compress a compliant and slender spring prone to buckling at low forces (<3N. We know that factors such as aging and neurodegenerative conditions bring deteriorating physiological changes (e.g., at the level of motor cortex, cerebellum, and basal ganglia, which lead to an overall loss of dexterous ability. However, little is known about how these changes reflect upon the dynamics of the underlying biological system. The spring-hand system exhibits nonlinear dynamical behavior and here we characterize the dynamical behavior of the phase portraits using attractor reconstruction. Thirty participants performed the SD test: 10 young adults, 10 older adults, and 10 older adults with Parkinson's disease (PD. We used delayed embedding of the applied force to reconstruct its attractor. We characterized the distribution of points of the phase portraits by their density (number of distant points and interquartile range and geometric features (trajectory length and size. We find phase portraits from older adults exhibit more distant points (p = 0.028 than young adults and participants with PD have larger interquartile ranges (p = 0.001, trajectory lengths (p = 0.005, and size (p = 0.003 than their healthy counterparts. The increased size of the phase portraits with healthy aging suggests a change in the dynamical properties of the system, which may represent a weakening of the neural control strategy. In contrast, the distortion of the attractor in PD suggests a fundamental change in the underlying biological system, and disruption of the neural control strategy. This ability to detect differences in the biological mechanisms of dexterity in healthy and pathological aging provides a simple means to assess their disruption in neurodegenerative conditions and justifies further studies to understand the link with the physiological changes.

Mid-point for open-ended income category and the effect of equivalence scales on the income-health relationship.

Science.gov (United States)

Celeste, Roger Keller; Bastos, João Luiz

2013-12-01

To estimate the mid-point of an open-ended income category and to assess the impact of two equivalence scales on income-health associations. Data were obtained from the 2010 Brazilian Oral Health Survey (Pesquisa Nacional de Saúde Bucal--SBBrasil 2010). Income was converted from categorical to two continuous variables (per capita and equivalized) for each mid-point. The median mid-point was R$ 14,523.50 and the mean, R$ 24,507.10. When per capita income was applied, 53% of the population were below the poverty line, compared with 15% with equivalized income. The magnitude of income-health associations was similar for continuous income, but categorized equivalized income tended to decrease the strength of association.

Management by Trajectory: Trajectory Management Study Report

Science.gov (United States)

Leiden, Kenneth; Atkins, Stephen; Fernandes, Alicia D.; Kaler, Curt; Bell, Alan; Kilbourne, Todd; Evans, Mark

2017-01-01

In order to realize the full potential of the Next Generation Air Transportation System (NextGen), improved management along planned trajectories between air navigation service providers (ANSPs) and system users (e.g., pilots and airline dispatchers) is needed. Future automation improvements and increased data communications between aircraft and ground automation would make the concept of Management by Trajectory (MBT) possible.

A Comparison of the Influence of Anticipated Death Trajectory and Personal Values on End-of-Life Care Preferences: A Qualitative Analysis.

Science.gov (United States)

Supiano, Katherine P; McGee, Nancy; Dassel, Kara B; Utz, Rebecca

2017-08-17

We examined anticipated preferences for end-of-life (EOL) care in healthy older adults in the context of various terminal disease scenarios to explore the relationship between personal values and diseases and conditions that would influence EOL care choices. Qualitative Descriptive Analysis was used to derive themes and the relationship between EOL preference themes and personal value themes in 365 respondents in a national sample of healthy older adults who completed a survey on their anticipated preferences for end-of-life (EOL) care. Reluctance to burden close others was the most frequently voiced personal value across all conditions affecting EOL preferences, followed by the personal value of quality of life. Concern about whether one's wishes would be honored was more commonly voiced in the context of hypothetical, prospective terminal cancer than in neurological conditions. Respondents who voiced desire for autonomy in how they would die clearly attributed extreme pain as the primary influence on EOL preferences. Comprehensive assessment of patient personal values should include consideration of particular chronic disease scenarios and death trajectories to fully inform EoL preferences. Because personal values do influence EOL preferences, care should be taken to ascertain patient values when presenting diagnoses, prognoses, and treatment options. In particular, patients and families of patients with progressive neurological diseases will likely face a time when the patient cannot self-represent EOL wishes. Early discussion of values and preferences, particularly in the context of cognitive disease is vital to assure patient-directed care.

Entangled trajectories Hamiltonian dynamics for treating quantum nuclear effects

Science.gov (United States)

Smith, Brendan; Akimov, Alexey V.

2018-04-01

A simple and robust methodology, dubbed Entangled Trajectories Hamiltonian Dynamics (ETHD), is developed to capture quantum nuclear effects such as tunneling and zero-point energy through the coupling of multiple classical trajectories. The approach reformulates the classically mapped second-order Quantized Hamiltonian Dynamics (QHD-2) in terms of coupled classical trajectories. The method partially enforces the uncertainty principle and facilitates tunneling. The applicability of the method is demonstrated by studying the dynamics in symmetric double well and cubic metastable state potentials. The methodology is validated using exact quantum simulations and is compared to QHD-2. We illustrate its relationship to the rigorous Bohmian quantum potential approach, from which ETHD can be derived. Our simulations show a remarkable agreement of the ETHD calculation with the quantum results, suggesting that ETHD may be a simple and inexpensive way of including quantum nuclear effects in molecular dynamics simulations.

Trajectory phase transitions and dynamical Lee-Yang zeros of the Glauber-Ising chain.

Science.gov (United States)

Hickey, James M; Flindt, Christian; Garrahan, Juan P

2013-07-01

We examine the generating function of the time-integrated energy for the one-dimensional Glauber-Ising model. At long times, the generating function takes on a large-deviation form and the associated cumulant generating function has singularities corresponding to continuous trajectory (or "space-time") phase transitions between paramagnetic trajectories and ferromagnetically or antiferromagnetically ordered trajectories. In the thermodynamic limit, the singularities make up a whole curve of critical points in the complex plane of the counting field. We evaluate analytically the generating function by mapping the generator of the biased dynamics to a non-Hermitian Hamiltonian of an associated quantum spin chain. We relate the trajectory phase transitions to the high-order cumulants of the time-integrated energy which we use to extract the dynamical Lee-Yang zeros of the generating function. This approach offers the possibility to detect continuous trajectory phase transitions from the finite-time behavior of measurable quantities.

Trajectories of BMI change impact glucose and insulin metabolism.

Science.gov (United States)

Walsh, E I; Shaw, J; Cherbuin, N

2018-03-01

The aim of this study was to examine, in a community setting, whether trajectory of weight change over twelve years is associated with glucose and insulin metabolism at twelve years. Participants were 532 community-living middle-aged and elderly adults from the Personality and Total Health (PATH) Through Life study. They spanned the full weight range (underweight/normal/overweight/obese). Latent class analysis and multivariate generalised linear models were used to investigate the association of Body Mass Index (BMI, kg/m 2 ) trajectory over twelve years with plasma insulin (μlU/ml), plasma glucose (mmol/L), and HOMA2 insulin resistance and beta cell function at follow-up. All models were adjusted for age, gender, hypertension, pre-clinical diabetes status (normal fasting glucose or impaired fasting glucose) and physical activity. Four weight trajectories were extracted; constant normal (mean baseline BMI = 25; follow-up BMI = 25), constant high (mean baseline BMI = 36; follow-up BMI = 37), increase (mean baseline BMI = 26; follow-up BMI = 32) and decrease (mean baseline BMI = 34; follow-up BMI = 28). At any given current BMI, individuals in the constant high and increase trajectories had significantly higher plasma insulin, greater insulin resistance, and higher beta cell function than those in the constant normal trajectory. Individuals in the decrease trajectory did not differ from the constant normal trajectory. Current BMI significantly interacted with preceding BMI trajectory in its association with plasma insulin, insulin resistance, and beta cell function. The trajectory of preceding weight has an independent effect on blood glucose metabolism beyond body weight measured at any given point in time. Copyright © 2017 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier

Enabling Parametric Optimal Ascent Trajectory Modeling During Early Phases of Design

Science.gov (United States)

Holt, James B.; Dees, Patrick D.; Diaz, Manuel J.

2015-01-01

During the early phases of engineering design, the costs committed are high, costs incurred are low, and the design freedom is high. It is well documented that decisions made in these early design phases drive the entire design's life cycle. In a traditional paradigm, key design decisions are made when little is known about the design. As the design matures, design changes become more difficult -- in both cost and schedule -- to enact. Indeed, the current capability-based paradigm that has emerged because of the constrained economic environment calls for the infusion of knowledge acquired during later design phases into earlier design phases, i.e. bring knowledge acquired during preliminary and detailed design into pre-conceptual and conceptual design. An area of critical importance to launch vehicle design is the optimization of its ascent trajectory, as the optimal trajectory will be able to take full advantage of the launch vehicle's capability to deliver a maximum amount of payload into orbit. Hence, the optimal ascent trajectory plays an important role in the vehicle's affordability posture as the need for more economically viable access to space solutions are needed in today's constrained economic environment. The problem of ascent trajectory optimization is not a new one. There are several programs that are widely used in industry that allows trajectory analysts to, based on detailed vehicle and insertion orbit parameters, determine the optimal ascent trajectory. Yet, little information is known about the launch vehicle early in the design phase - information that is required of many different disciplines in order to successfully optimize the ascent trajectory. Thus, the current paradigm of optimizing ascent trajectories involves generating point solutions for every change in a vehicle's design parameters. This is often a very tedious, manual, and time-consuming task for the analysts. Moreover, the trajectory design space is highly non-linear and multi

Trajectories of Depressive Symptoms in Older Adults and Risk of Dementia.

Science.gov (United States)

Kaup, Allison R; Byers, Amy L; Falvey, Cherie; Simonsick, Eleanor M; Satterfield, Suzanne; Ayonayon, Hilsa N; Smagula, Stephen F; Rubin, Susan M; Yaffe, Kristine

2016-05-01

Depression has been identified as a risk factor for dementia. However, most studies have measured depressive symptoms at only one time point, and older adults may show different patterns of depressive symptoms over time. To investigate the association between trajectories of depressive symptoms and risk of dementia in older adults. This was a prospective cohort investigation of black and white community-dwelling older adults in the Health, Aging, and Body Composition study. Participants were enrolled between May 1997 and June 1998 and followed up through 2001-2002. The dates of this analysis were September 2014 to December 2015. The setting was community research centers in Memphis, Tennessee, and Pittsburgh, Pennsylvania. Trajectories of depressive symptoms were assessed from baseline to year 5. Symptoms were measured with the Center for Epidemiologic Studies Depression Scale Short Form, and trajectories were calculated using latent class growth curve analysis. Incident dementia through year 11, determined by dementia medication use, hospital records, or significant cognitive decline (≥1.5 SD race-specific decline on the Modified Mini-Mental State Examination). We examined the association between depressive symptom trajectories and dementia incidence using Cox proportional hazards regression models adjusted for demographics, health factors that differed between groups, and cognition during the depressive symptom assessment period (baseline to year 5). The analytic cohort included 2488 black and white older adults with repeated depressive symptom assessments from baseline to year 5 who were free of dementia throughout that period. Their mean (SD) age at baseline was 74.0 (2.8) years, and 53.1% (n = 1322) were female. The following 3 depressive symptom trajectories were identified: consistently minimal symptoms (62.0% [n = 1542] of participants), moderate and increasing symptoms (32.2% [n = 801] of participants), and high and increasing symptoms (5

Guidelines for time-to-event end point definitions in breast cancer trials: results of the DATECAN initiative (Definition for the Assessment of Time-to-event Endpoints in CANcer trials)†.

Science.gov (United States)

Gourgou-Bourgade, S; Cameron, D; Poortmans, P; Asselain, B; Azria, D; Cardoso, F; A'Hern, R; Bliss, J; Bogaerts, J; Bonnefoi, H; Brain, E; Cardoso, M J; Chibaudel, B; Coleman, R; Cufer, T; Dal Lago, L; Dalenc, F; De Azambuja, E; Debled, M; Delaloge, S; Filleron, T; Gligorov, J; Gutowski, M; Jacot, W; Kirkove, C; MacGrogan, G; Michiels, S; Negreiros, I; Offersen, B V; Penault Llorca, F; Pruneri, G; Roche, H; Russell, N S; Schmitt, F; Servent, V; Thürlimann, B; Untch, M; van der Hage, J A; van Tienhoven, G; Wildiers, H; Yarnold, J; Bonnetain, F; Mathoulin-Pélissier, S; Bellera, C; Dabakuyo-Yonli, T S

2015-05-01

Using surrogate end points for overall survival, such as disease-free survival, is increasingly common in randomized controlled trials. However, the definitions of several of these time-to-event (TTE) end points are imprecisely which limits interpretation and cross-trial comparisons. The estimation of treatment effects may be directly affected by the definitions of end points. The DATECAN initiative (Definition for the Assessment of Time-to-event Endpoints in CANcer trials) aims to provide recommendations for definitions of TTE end points. We report guidelines for randomized cancer clinical trials (RCTs) in breast cancer. A literature review was carried out to identify TTE end points (primary or secondary) reported in publications of randomized trials or guidelines. An international multidisciplinary panel of experts proposed recommendations for the definitions of these end points based on a validated consensus method that formalize the degree of agreement among experts. Recommended guidelines for the definitions of TTE end points commonly used in RCTs for breast cancer are provided for non-metastatic and metastatic settings. The use of standardized definitions should facilitate comparisons of trial results and improve the quality of trial design and reporting. These guidelines could be of particular interest to those involved in the design, conducting, reporting, or assessment of RCT. © The Author 2015. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

New force replica exchange method and protein folding pathways probed by force-clamp technique.

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Kouza, Maksim; Hu, Chin-Kun; Li, Mai Suan

2008-01-28

We have developed a new extended replica exchange method to study thermodynamics of a system in the presence of external force. Our idea is based on the exchange between different force replicas to accelerate the equilibrium process. This new approach was applied to obtain the force-temperature phase diagram and other thermodynamical quantities of the three-domain ubiquitin. Using the C(alpha)-Go model and the Langevin dynamics, we have shown that the refolding pathways of single ubiquitin depend on which terminus is fixed. If the N end is fixed then the folding pathways are different compared to the case when both termini are free, but fixing the C terminal does not change them. Surprisingly, we have found that the anchoring terminal does not affect the pathways of individual secondary structures of three-domain ubiquitin, indicating the important role of the multidomain construction. Therefore, force-clamp experiments, in which one end of a protein is kept fixed, can probe the refolding pathways of a single free-end ubiquitin if one uses either the polyubiquitin or a single domain with the C terminus anchored. However, it is shown that anchoring one end does not affect refolding pathways of the titin domain I27, and the force-clamp spectroscopy is always capable to predict folding sequencing of this protein. We have obtained the reasonable estimate for unfolding barrier of ubiquitin, using the microscopic theory for the dependence of unfolding time on the external force. The linkage between residue Lys48 and the C terminal of ubiquitin is found to have the dramatic effect on the location of the transition state along the end-to-end distance reaction coordinate, but the multidomain construction leaves the transition state almost unchanged. We have found that the maximum force in the force-extension profile from constant velocity force pulling simulations depends on temperature nonlinearly. However, for some narrow temperature interval this dependence becomes

Cognitive loading affects motor awareness and movement kinematics but not locomotor trajectories during goal-directed walking in a virtual reality environment.

Directory of Open Access Journals (Sweden)

Oliver Alan Kannape

Full Text Available The primary purpose of this study was to investigate the effects of cognitive loading on movement kinematics and trajectory formation during goal-directed walking in a virtual reality (VR environment. The secondary objective was to measure how participants corrected their trajectories for perturbed feedback and how participants' awareness of such perturbations changed under cognitive loading. We asked 14 healthy young adults to walk towards four different target locations in a VR environment while their movements were tracked and played back in real-time on a large projection screen. In 75% of all trials we introduced angular deviations of ±5° to ±30° between the veridical walking trajectory and the visual feedback. Participants performed a second experimental block under cognitive load (serial-7 subtraction, counter-balanced across participants. We measured walking kinematics (joint-angles, velocity profiles and motor performance (end-point-compensation, trajectory-deviations. Motor awareness was determined by asking participants to rate the veracity of the feedback after every trial. In-line with previous findings in natural settings, participants displayed stereotypical walking trajectories in a VR environment. Our results extend these findings as they demonstrate that taxing cognitive resources did not affect trajectory formation and deviations although it interfered with the participants' movement kinematics, in particular walking velocity. Additionally, we report that motor awareness was selectively impaired by the secondary task in trials with high perceptual uncertainty. Compared with data on eye and arm movements our findings lend support to the hypothesis that the central nervous system (CNS uses common mechanisms to govern goal-directed movements, including locomotion. We discuss our results with respect to the use of VR methods in gait control and rehabilitation.

Differences in center of pressure trajectory between normal and steppage gait

Science.gov (United States)

Jamshidi, Nima; Rostami, Mostafa; Najarian, Siamak; Menhaj, Mohammad Bagher; Saadatnia, Mohammad; Salami, Firooz

2010-01-01

BACKGROUND: This pilot study aimed to assess the differences in center of pressure trajectory in neuropathic patients with steppage gait. Steppage gait has previously been evaluated by several biomechanical methods, but plantar pressure distribution has been much less studied. The purpose of this study was to analyze the changes in center of pressure trajectory using a force plate. METHODS: The steppage gait group was selected from the patients using drop foot brace (25 male) and the control group was selected from Isfahan university students (20 male). They walked at self- selected speed at a mean of ten trials (+2) to collect the center of pressure using a force plate. Center of pressure patterns were categorized into four patterns based on the center of pressure displacement magnitude (spatial features) through time (temporal features) when the longitudinal axis of the insole was plotted as the Y- axis and the transverse axis of the insole as X- axis during stance phase. RESULTS: The horizontal angle measured from center of pressure linear regression was positive in the control group (4.6 ± 2.4) (p < 0.005), but negative in the patient group (- 2.3 ± 1.6) (p < 0.005). CONCLUSIONS: The finding of this research measured center of pressure trajectory in steppage gait over time, which is useful for designing better shoe sole and also orthopaedic device and better understanding of stability in patients with drop foot. PMID:21526056

Differences in center of pressure trajectory between normal and steppage gait

Directory of Open Access Journals (Sweden)

Nima Jamshidi

2010-01-01

Full Text Available Background: This pilot study aimed to assess the differences in center of pressure trajectory in neuropathic patients with steppage gait. Steppage gait has previously been evaluated by several biomechanical methods, but plantar pressure distribution has been much less studied. The purpose of this study was to analyze the changes in center of pressure tra-jectory using a force plate. Methods: The steppage gait group was selected from the patients using drop foot brace (25 male and the control group was selected from Isfahan university students (20 male. They walked at self- selected speed at a mean of ten tri-als (+2 to collect the center of pressure using a force plate. Center of pressure patterns were categorized into four pat-terns based on the center of pressure displacement magnitude (spatial features through time (temporal features when the longitudinal axis of the insole was plotted as the Y- axis and the transverse axis of the insole as X- axis during stance phase. Results: The horizontal angle measured from center of pressure linear regression was positive in the control group (4.6 ± 2.4 (p < 0.005, but negative in the patient group (- 2.3 ± 1.6 (p < 0.005. Conclusions: The finding of this research measured center of pressure trajectory in steppage gait over time, which is useful for designing better shoe sole and also orthopaedic device and better understanding of stability in patients with drop foot.

Repetitive Rockfall Trajectory Testing

Directory of Open Access Journals (Sweden)

Axel Volkwein

2018-03-01

Full Text Available Numerical simulations of rockfall trajectories are a standard procedure for evaluating rockfall hazards. For these simulations, corresponding software codes must be calibrated and evaluated based on field data. This study addresses methods of repeatable rockfall tests, and investigates whether it is possible to produce traceable and statistically analysable data. A testing series is described extensively covering how to conduct rockfall experiments and how certain elements of rockfall trajectories can be measured. The tests use acceleration and rotation sensors inside test blocks, a system to determine block positions over time, surveying measurements, and video recordings. All systems are evaluated regarding their usability in the field and for analyses. The highly detailed description of testing methods is the basis for sound understanding and reproducibility of the tests. This article serves as a reference for future publications and other rockfall field tests, both as a guide and as a basis for comparisons. First analyses deliver information on runout with a shadow angle ranging between 21 and 45 degrees for a slope consisting of homogeneous soft soil. A digital elevation model of the test site as well as point clouds of the used test blocks are part of this publication.

An alternate end design for SSC dipoles

International Nuclear Information System (INIS)

Peters, C.; Caspi, S.; Taylor, C.

1989-02-01

Experience in the SSC dipole program has shown that fabrication of cylindrical coil ends is difficult. Cable stiffness requires large forces to maintain the proper position of the conductors in the end during winding. After winding, the coil ends remain distorted nd significant motion of the need conductors is required to force the coil end into the molding cavity. Local mechanical stresses are high during this process and extra pieces of insulation are required to prevent turn-to-turn shorts from developing during the winding and molding steps. Prior to assembly the coil end is compressed in a mold cavity and injected with a filler material to correct surface irregularities and fill voids in the end. LBL has developed an alternate design which permits the conductors to be wound over the end using minimal force and technician coerosion. The conductors are placed on a conical surface where the largest diameter over the outer layer conductors is 10 cm. No coil end spaces or insulation pieces between turns are required. The conductor geometry was analytically optimized to meet SSC multipole requirements for the ends. The first 1-m dipole utilizing this end geometry has been constructed and successfully tested. Design and construction data are presented. Also model test results, including training and multipole measurements of the end are given. 1 ref., 12 figs., 3 tabs

Forced convective boiling of water inside helically coiled tube. Characteristics of oscillation of dryout point

International Nuclear Information System (INIS)

Nagai, Niro; Sugiyama, Kenta; Takeuchi, Masanori; Yoshikawa, Shinji; Yamamoto, Fujio

2006-01-01

The helically coiled tube of heat exchanger is used for the evaporator of prototype fast breeder reactor 'Monju'. This paper aims at the grasp of two-phase flow phenomena of forced convective boiling of water inside helical coiled tube, especially focusing on oscillation phenomena of dryout point. A glass-made helically coiled tube was used to observe the inside water boiling behavior flowing upward, which was heated by high temperature oil outside the tube. This oil was also circulated through a glass made tank to provide the heat source for water evaporation. The criterion for oscillation of dryout point was found to be a function of inlet liquid velocity and hot oil temperature. The observation results suggest the mechanism of dryout point oscillation mainly consists of intensive nucleate boiling near the dryout point and evaporation of thin liquid film flowing along the helical tube. In addition, the oscillation characteristics were experimentally confirmed. As inlet liquid velocity increases, oscillation amplitude also increases but oscillation cycle does not change so much. As hot oil temperature increases, oscillation amplitude and cycle gradually decreases. (author)

Research of a New 6-Dof Force Feedback Hand Controller System

Directory of Open Access Journals (Sweden)

Xin Gao

2014-01-01

Full Text Available The field of teleoperation with force telepresence has expanded its scope to include manipulation at different scales and in virtual worlds, and the key component of which is force feedback hand controller. This paper presents a novel force feedback hand controller system, including a 3-dof translational and 3-dof rotational hand controllers, respectively, to implement position and posture teleoperation of the robot end effector. The 3-dof translational hand controller adopts innovative three-axes decoupling structure based on the linear motor; the 3-dof rotational hand controller adopts serial mechanism based on three-axes intersecting at one point, improving its overall stiffness. Based on the kinematics, statics, and dynamics analyses for two platforms separately, the system applies big closed-loop force control method based on the zero force/torque, improving the feedback force/torque accuracy effectively. Experimental results show that self-developed 6-dof force feedback hand controller has good mechanical properties. The translational hand controller has the following advantages: simple kinematics solver, fast dynamic response, and better than 0.05 mm accuracy of three-axis end positioning, while the advantages of the rotational hand controller are wide turning space, larger than 1 Nm feedback, greater than 180 degrees of operating space of three axes, respectively, and high operation precision.

Multivariate stability of force-reflecting teleoperation: Structures of finite and infinite zeros

International Nuclear Information System (INIS)

Daniel, R.W.; McAree, P.R.

2000-01-01

This paper presents a stability analysis of force-position teleoperation under general end-effector contact. The analysis is based on the finite and infinite zero structure of the multivariable root-locus resulting from modulation of the environment stiffness. The starting point is an analysis of the stability of robot force control, motivated by the observation that the human-operator in a force reflection loop acts as a force servo, generating position commands in response to reflected force. Asymptotic root loci properties are used to establish passivity conditions on force feedback to give root locus interpretations of the well-known results that (1) feedback via the inverse joint Jacobian can lead to (kinematic) instability and that (2) passivity is preserved by kinematically proper force feedback through the transpose of the joint angle Jacobian. It is demonstrated that a fully constrained force-position teleoperation loop has an identical infinite zero structure to that of a slave manipulation under kinematically proper force control and that the dominant vibration modes of a force-position loop are fully described by a multivariable analogue of the single-input single-output pseudo-system investigated in a study by Daniel and McAree. Extension of the analysis to cover partial end-effector constraint provides a design tool for teleoperation control and serves to aid selection of teleoperation slate-arms. The paper concludes by giving a passivity condition for multiple-input multiple-output force-position teleoperation for stable contact against all environments

Trajectory planning of tokamak flexible in-vessel inspection robot

Energy Technology Data Exchange (ETDEWEB)

Wang, Hesheng [Department of Automation, Shanghai Jiao Tong University, 200240 Shanghai (China); Key Laboratory of System Control and Information Processing, Ministry of Education of China, 200240 Shanghai (China); Chen, Weidong, E-mail: wdchen@sjtu.edu.cn [Department of Automation, Shanghai Jiao Tong University, 200240 Shanghai (China); Key Laboratory of System Control and Information Processing, Ministry of Education of China, 200240 Shanghai (China); Lai, Yinping; He, Tao [Department of Automation, Shanghai Jiao Tong University, 200240 Shanghai (China); Key Laboratory of System Control and Information Processing, Ministry of Education of China, 200240 Shanghai (China)

2015-10-15

Highlights: • A tokamak flexible in-vessel inspection robot is designed. • Two trajectory planning methods are used to ensure the full coverage of the first wall scanning. • The method is tested on a simulated platform of EAST with the flexible in-vessel inspection robot. • Experimental results show the effectiveness of the proposed algorithm. - Abstract: Tokamak flexible in-vessel inspection robot is mainly designed to carry a camera for close observation of the first wall of the vacuum vessel, which is essential for the maintenance of the future tokamak reactor without breaking the working condition of the vacuum vessel. A tokamak flexible in-vessel inspection robot is designed. In order to improve efficiency of the remote maintenance, it is necessary to design a corresponding trajectory planning algorithm to complete the automatic full coverage scanning of the complex tokamak cavity. Two different trajectory planning methods, RS (rough scanning) and FS (fine scanning), according to different demands of the task, are used to ensure the full coverage of the first wall scanning. To quickly locate the damage position, the first trajectory planning method is targeted for quick and wide-ranging scan of the tokamak D-shaped section, and the second one is for careful observation. Furthermore, both of the two different trajectory planning methods can ensure the full coverage of the first wall scanning with an optimal end posture. The method is tested on a simulated platform of EAST (Experimental Advanced Superconducting Tokamak) with the flexible in-vessel inspection robot, and the results show the effectiveness of the proposed algorithm.

Trajectory planning of tokamak flexible in-vessel inspection robot

International Nuclear Information System (INIS)

Wang, Hesheng; Chen, Weidong; Lai, Yinping; He, Tao

2015-01-01

Highlights: • A tokamak flexible in-vessel inspection robot is designed. • Two trajectory planning methods are used to ensure the full coverage of the first wall scanning. • The method is tested on a simulated platform of EAST with the flexible in-vessel inspection robot. • Experimental results show the effectiveness of the proposed algorithm. - Abstract: Tokamak flexible in-vessel inspection robot is mainly designed to carry a camera for close observation of the first wall of the vacuum vessel, which is essential for the maintenance of the future tokamak reactor without breaking the working condition of the vacuum vessel. A tokamak flexible in-vessel inspection robot is designed. In order to improve efficiency of the remote maintenance, it is necessary to design a corresponding trajectory planning algorithm to complete the automatic full coverage scanning of the complex tokamak cavity. Two different trajectory planning methods, RS (rough scanning) and FS (fine scanning), according to different demands of the task, are used to ensure the full coverage of the first wall scanning. To quickly locate the damage position, the first trajectory planning method is targeted for quick and wide-ranging scan of the tokamak D-shaped section, and the second one is for careful observation. Furthermore, both of the two different trajectory planning methods can ensure the full coverage of the first wall scanning with an optimal end posture. The method is tested on a simulated platform of EAST (Experimental Advanced Superconducting Tokamak) with the flexible in-vessel inspection robot, and the results show the effectiveness of the proposed algorithm.

Analysis of kinematically redundant reaching movements using the equilibrium-point hypothesis.

Science.gov (United States)

Cesari, P; Shiratori, T; Olivato, P; Duarte, M

2001-03-01

Six subjects performed a planar reaching arm movement to a target while unpredictable perturbations were applied to the endpoint; the perturbations consisted of pulling springs having different stiffness. Two conditions were applied; in the first, subjects had to reach for the target despite the perturbation, in the second condition, the subjects were asked to not correct the motion as a perturbation was applied. We analyzed the kinematics profiles of the three arm segments and, by means of inverse dynamics, calculated the joint torques. The framework of the equilibrium-point (EP) hypothesis, the lambda model, allowed the reconstruction of the control variables, the "equilibrium trajectories", in the "do not correct" condition for the wrist and the elbow joints as well as for the end point final position, while for the other condition, the reconstruction was less reliable. The findings support and extend to a multiple-joint planar movement, the paradigm of the EP hypothesis along with the "do not correct" instruction.

Machine learning of accurate energy-conserving molecular force fields

Science.gov (United States)

Chmiela, Stefan; Tkatchenko, Alexandre; Sauceda, Huziel E.; Poltavsky, Igor; Schütt, Kristof T.; Müller, Klaus-Robert

2017-01-01

Using conservation of energy—a fundamental property of closed classical and quantum mechanical systems—we develop an efficient gradient-domain machine learning (GDML) approach to construct accurate molecular force fields using a restricted number of samples from ab initio molecular dynamics (AIMD) trajectories. The GDML implementation is able to reproduce global potential energy surfaces of intermediate-sized molecules with an accuracy of 0.3 kcal mol−1 for energies and 1 kcal mol−1 Å̊−1 for atomic forces using only 1000 conformational geometries for training. We demonstrate this accuracy for AIMD trajectories of molecules, including benzene, toluene, naphthalene, ethanol, uracil, and aspirin. The challenge of constructing conservative force fields is accomplished in our work by learning in a Hilbert space of vector-valued functions that obey the law of energy conservation. The GDML approach enables quantitative molecular dynamics simulations for molecules at a fraction of cost of explicit AIMD calculations, thereby allowing the construction of efficient force fields with the accuracy and transferability of high-level ab initio methods. PMID:28508076

Satellite Images-Based Obstacle Recognition and Trajectory Generation for Agricultural Vehicles

Directory of Open Access Journals (Sweden)

Mehmet Bodur

2015-12-01

Full Text Available In this study, a method for the generation of tracking trajectory points, detection and positioning of obstacles in agricultural fields have been presented. Our principal contribution is to produce traceable GPS trajectories for agricultural vehicles to be utilized by path planning algorithms, rather than a new path planning algorithm. The proposed system works with minimal initialization requirements, specifically, a single geographical coordinate entry of an agricultural field. The automation of agricultural plantation requires many aspects to be addressed, many of which have been covered in previous studies. Depending on the type of crop, different agricultural vehicles may be used in the field. However, regardless of their application, they all follow a specified trajectory in the field. This study takes advantage of satellite images for the detection and positioning of obstacles, and the generation of GPS trajectories in the agricultural realm. A set of image processing techniques is applied in Matlab for detection and positioning.

Thematic and athematic present endings in Balto-Slavic and Indo-European

Directory of Open Access Journals (Sweden)

Frederik Kortlandt

2015-09-01

Full Text Available While the original primary thematic endings were preserved quite well in Balto-Slavic, they were often replaced by the corresponding athematic endings following the thematic vowel *‑e/o‑ in the other Indo-European languages, thus bringing them into line with the secondary endings. Without taking the semantics of the thematic flexion into consideration, Warren Cowgill has forcefully defended the traditional view that apart from the 1st sg. ending *‑ō, the thematic endings were identical with the athematic endings preceded by the thematic vowel *‑e/o‑ in Proto-Indo-European. The main point to be taken into consideration is that the rich and heterogeneous material of Balto-Slavic allows a reconstruction which is on the same level as that of Indo-Iranian and Greek. It confirms the view that our reconstructions have a bias toward the languages on which they are primarily based (Cowgill’s “trusty trio Hittite, Sanskrit, Greek”. The history of linguistic reconstruction shows a gradual shift away from the principal languages.

Trajectory of an oil spill off Goa, eastern Arabian Sea: Field observations and simulations

Energy Technology Data Exchange (ETDEWEB)

Vethamony, P. [National Institute of Oceanography, Dona Paula, Goa 403 004 (India)]. E-mail: mony@nio.org; Sudheesh, K. [National Institute of Oceanography, Dona Paula, Goa 403 004 (India); Babu, M.T. [National Institute of Oceanography, Dona Paula, Goa 403 004 (India); Jayakumar, S. [National Institute of Oceanography, Dona Paula, Goa 403 004 (India); Manimurali, R. [National Institute of Oceanography, Dona Paula, Goa 403 004 (India); Saran, A.K. [National Institute of Oceanography, Dona Paula, Goa 403 004 (India); Sharma, L.H. [Indian Coast Guard, District HQ-11, MPT Old Admin Building, Mormugao Harbour, Goa 403 803 (India); Rajan, B. [Indian Coast Guard, District HQ-11, MPT Old Admin Building, Mormugao Harbour, Goa 403 803 (India); Srivastava, M. [Indian Coast Guard, District HQ-11, MPT Old Admin Building, Mormugao Harbour, Goa 403 803 (India)

2007-07-15

An oil spill occurred off Goa, west coast of India, on 23 March 2005 due to collision of two vessels. In general, fair weather with weak winds prevails along the west coast of India during March. In that case, the spill would have moved slowly and reached the coast. However, in 2005 when this event occurred, relatively stronger winds prevailed, and these winds forced the spill to move away from the coast. The spill trajectory was dominated by winds rather than currents. The MIKE21 Spill Analysis model was used to simulate the spill trajectory. The observed spill trajectory and the slick area were in agreement with the model simulations. The present study illustrates the importance of having pre-validated trajectories of spill scenarios for selecting eco-sensitive regions for preparedness and planning suitable response strategies whenever spill episodes occur. - This is the first time model results have been compared with real oil spill observations along an Indian Coast.

Skipping Orbits, Traversing Trajectories, and Quantum Ballistic Transport in Microstructures

NARCIS (Netherlands)

Beenakker, C.W.J.; Houten, H. van; Wees, B.J. van

1989-01-01

Three topics of current interest in the study of quantum ballistic transport in a two-dimensional electron gas are discussed, with an emphasis on correspondences between classical trajectories and quantum states in the various experimental geometries. We consider the quantized conductance of point

Mid-point for open-ended income category and the effect of equivalence scales on the income-health relationship

Directory of Open Access Journals (Sweden)

Roger Keller Celeste

2013-12-01

Full Text Available To estimate the mid-point of an open-ended income category and to assess the impact of two equivalence scales on income-health associations. Data were obtained from the 2010 Brazilian Oral Health Survey ( Pesquisa Nacional de Saúde Bucal – SBBrasil 2010. Income was converted from categorical to two continuous variables ( per capita and equivalized for each mid-point. The median mid-point was R$ 14,523.50 and the mean, R$ 24,507.10. When per capita income was applied, 53% of the population were below the poverty line, compared with 15% with equivalized income. The magnitude of income-health associations was similar for continuous income, but categorized equivalized income tended to decrease the strength of association.

Physical Forces between Humans and How Humans Attract and Repel Each Other Based on Their Social Interactions in an Online World.

Directory of Open Access Journals (Sweden)

Stefan Thurner

Full Text Available Physical interactions between particles are the result of the exchange of gauge bosons. Human interactions are mediated by the exchange of messages, goods, money, promises, hostilities, etc. While in the physical world interactions and their associated forces have immediate dynamical consequences (Newton's laws the situation is not clear for human interactions. Here we quantify the relative acceleration between humans who interact through the exchange of messages, goods and hostilities in a massive multiplayer online game. For this game we have complete information about all interactions (exchange events between about 430,000 players, and about their trajectories (movements in the metric space of the game universe at any point in time. We use this information to derive "interaction potentials" for communication, trade and attacks and show that they are harmonic in nature. Individuals who exchange messages and trade goods generally attract each other and start to separate immediately after exchange events end. The form of the interaction potential for attacks mirrors the usual "hit-and-run" tactics of aggressive players. By measuring interaction intensities as a function of distance, velocity and acceleration, we show that "forces" between players are directly related to the number of exchange events. We find an approximate power-law decay of the likelihood for interactions as a function of distance, which is in accordance with previous real world empirical work. We show that the obtained potentials can be understood with a simple model assuming an exchange-driven force in combination with a distance-dependent exchange rate.

Cognitive Trajectory Changes Over 20 Years Before Dementia Diagnosis: A Large Cohort Study.

Science.gov (United States)

Li, Ge; Larson, Eric B; Shofer, Jane B; Crane, Paul K; Gibbons, Laura E; McCormick, Wayne; Bowen, James D; Thompson, Mary Lou

2017-12-01

Longitudinal studies have shown an increase in cognitive decline many years before clinical diagnosis of dementia. We sought to estimate changes, relative to "normal" aging, in the trajectory of scores on a global cognitive function test-the Cognitive Abilities Screening Instrument (CASI). A prospective cohort study. Community-dwelling members of a U.S. health maintenance organization. Individuals aged 65 and older who had no dementia diagnosis at baseline and had at least two visits with valid CASI test score (N = 4,315). Average longitudinal trajectories, including changes in trajectory before clinical diagnosis in those who would be diagnosed with dementia, were estimated for CASI item response theory (IRT) scores. The impact of sex, education level, and APOE genotype on cognitive trajectories was assessed. Increased cognitive decline relative to "normal" aging was evident in CASI IRT at least 10 years before clinical diagnosis. Male gender, lower education, and presence of ≥1 APOE ε4 alleles were associated with lower average IRT scores. In those who would be diagnosed with dementia, a trajectory change point was estimated at an average of 3.1 years (95% confidence interval 3.0-3.2) before clinical diagnosis, after which cognitive decline appeared to accelerate. The change point did not differ by sex, education level, or APOE ε4 genotype. There were subtle differences in trajectory slopes by sex and APOE ε4 genotype, but not by education. Decline in average global cognitive function was evident at least 10 years before clinical diagnosis of dementia. The decline accelerated about 3 years before clinical diagnosis. © 2017, Copyright the Authors Journal compilation © 2017, The American Geriatrics Society.

Diagnosis trajectories of prior multi-morbidity predict sepsis mortality

DEFF Research Database (Denmark)

Beck, Mette Kristina; Jensen, Anders Boeck; Nielsen, Annelaura Bach

2016-01-01

Sepsis affects millions of people every year, many of whom will die. In contrast to current survival prediction models for sepsis patients that primarily are based on data from within-admission clinical measurements (e.g. vital parameters and blood values), we aim for using the full disease histo...... of disease history to scoring based on within-admission clinical measurements emphasizing the value of long term data in novel patient scores that combine the two types of data.......Sepsis affects millions of people every year, many of whom will die. In contrast to current survival prediction models for sepsis patients that primarily are based on data from within-admission clinical measurements (e.g. vital parameters and blood values), we aim for using the full disease history...... recurrent trajectories of time-ordered co-morbidities had significantly increased sepsis mortality compared to those who did not follow a trajectory. We identified trajectories which significantly altered sepsis mortality, and found three major starting points in a combined temporal sepsis network: Alcohol...

Investigation of Calibrating Force Transducer Using Sinusoidal Force

International Nuclear Information System (INIS)

Zhang Li; Wang Yu; Zhang Lizhe

2010-01-01

Sinusoidal force calibration method was studied several years before at Physikalisch-Technische Bundesanstalt (PTB). A similar dynamic force calibration system is developed at Changcheng Institute of Metrology and Measurement (CIMM). It uses electro-dynamic shakers to generate dynamic force in the range from 1 N to 20 kN, and heterodyne laser interferometers are used for acceleration measurement. The force transducer to be calibrated is mounted on the shaker, and a mass block is screwed on the top of force transducer, the sinusoidal forces realized by accelerated load masses are traceable to acceleration and mass according to the force definition. The methods of determining Spatial-dependent acceleration on mass block and measuring the end mass of force transducer in dynamic force calibration are discussed in this paper.

Dietary pattern trajectories during 15 years of follow-up and HbA1c, insulin resistance and diabetes prevalence among Chinese adults.

Science.gov (United States)

Batis, Carolina; Mendez, Michelle A; Sotres-Alvarez, Daniela; Gordon-Larsen, Penny; Popkin, Barry

2014-08-01

Most research on dietary patterns and health outcomes does not include longitudinal exposure data. We used an innovative technique to capture dietary pattern trajectories and their association with haemoglobin A1c (HbA1c), homeostasis model of insulin resistance (HOMA-IR) and prevalence of newly diagnosed diabetes. We included 4096 adults with 3-6 waves of diet data (1991-2006) and biomarkers measured in 2009 from the China Health and Nutrition Survey. Diet was assessed with three 24-h recalls and a household food inventory. We used a dietary pattern previously identified with reduced rank regression that positively predicted diabetes in 2006 (high in wheat products and soy milk and low in rice, legumes, poultry, eggs and fish). We estimated a score for this dietary pattern for each subject at each wave. Using latent class trajectory analysis, we grouped subjects with similar dietary pattern score trajectories over time into five classes. Three trajectory classes were stable over time, and in two classes the diet became unhealthier over time (upward trend in dietary pattern score). Among two classes with similar scores in 2006, the one with the lower (healthier) initial score had an HbA1c 1.64% lower (-1.64 (95% CI -3.17 to -0.11)) and non-significantly a HOMA-IR 6.47% lower (-6.47 (-17.37 to 4.42)) and lower odds of diabetes (0.86 (0.44 to 1.67)). Our findings suggest that dietary pattern trajectories with healthier scores longitudinally had a lower HbA1c compared with those with unhealthier scores, even when the trajectories had similar scores in the end point. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

A Closer Look at Trends in Boiling Points of Hydrides: Using an Inquiry-Based Approach to Teach Intermolecular Forces of Attraction

Science.gov (United States)

Glazier, Samantha; Marano, Nadia; Eisen, Laura

2010-01-01

We describe how we use boiling-point trends of group IV-VII hydrides to introduce intermolecular forces in our first-year general chemistry classes. Starting with the idea that molecules in the liquid state are held together by some kind of force that must be overcome for boiling to take place, students use data analysis and critical reasoning to…

Changes in At-Risk American Men’s Crime and Substance Use Trajectories Following Fatherhood

Science.gov (United States)

Kerr, David C. R.; Capaldi, Deborah M.; Owen, Lee D.; Wiesner, Margit; Pears, Katherine C.

2011-01-01

Fatherhood can be a turning point in development and in men’s crime and substance use trajectories. At-risk boys (N = 206) were assessed annually from ages 12 to 31 years. Crime, arrest, and tobacco, alcohol, and marijuana use trajectories were examined. Marriage was associated with lower levels of crime and less frequent substance use. Following the birth of a first biological child, men’s crime trajectories showed slope decreases, and tobacco and alcohol use trajectories showed level decreases. The older men were when they became fathers, the greater the level decreases were in crime and alcohol use and the less the slope decreases were in tobacco and marijuana use. Patterns are consistent with theories of social control and social timetables. PMID:21984846

Trajectory generation for two robots cooperating to perform a task

International Nuclear Information System (INIS)

Lewis, C.L.

1995-01-01

This paper formulates an algorithm for trajectory generation for two robots cooperating to perform an assembly task. Treating the two robots as a single redundant system, this paper derives two Jacobian matrices which relate the joint rates of the entire system to the relative motion of the grippers with respect to one another. The advantage of this formulation over existing methods is that a variety of secondary criteria can be conveniently satisfied using motion in the null-space of the relative Jacobian. This paper presents methods for generating dual-arm joint trajectories which perform assembly tasks while at the same time avoiding obstacles and joint limits, and also maintaining constraints on the absolute position and orientation of the end-effectors

Trajectories for Novel and Detailed Traffic Information

DEFF Research Database (Denmark)

Krogh, Benjamin Bjerre; Andersen, Ove; Torp, Kristian

2012-01-01

the central metric free-flow speed from trajectories, instead of using point-based measurements such as induction-loops. This free-flow speed is widely used to compute and monitor the congestion level. The paper argues that the actual travel-time is a more accurate metric. The paper suggests a novel approach...... are correctly coordinated, and navigational device manufacturers to advice drivers in real-time on expected behavior of signalized intersections. The main conclusion is that trajectories can provide novel insight into the actual traffic situation that is not possible using existing approaches. Further...... to analyzing individual intersections that enables traffic analysts to compute queue lengths and estimated time to pass an intersection. Finally, the paper uses associative rule mining for evaluating green waves on road stretches. Such information can be used to verify that signalized intersections...

Flight Trajectory Planning for Fixed-Wing Aircraft in Loss of Thrust Emergencies

OpenAIRE

Paul, Saswata; Hole, Frederick; Zytek, Alexandra; Varela, Carlos A.

2017-01-01

Loss of thrust emergencies-e.g., induced by bird/drone strikes or fuel exhaustion-create the need for dynamic data-driven flight trajectory planning to advise pilots or control UAVs. While total loss of thrust trajectories to nearby airports can be pre-computed for all initial points in a 3D flight plan, dynamic aspects such as partial power and airplane surface damage must be considered for accuracy. In this paper, we propose a new Dynamic Data-Driven Avionics Software (DDDAS) approach which...

Dipole and Coulomb forces in electron capture dissociation and electron transfer dissociation mass spectroscopy.

Science.gov (United States)

Świerszcz, Iwona; Skurski, Piotr; Simons, Jack

2012-02-23

Ab initio electronic structure calculations were performed on a doubly charged polypeptide model H(+)-Lys(Ala)(19)-CO-CH(NH(2))-CH(2)-SS-CH(2)-(NH(2))CH-CO-(Ala)(19)-Lys-H(+) consisting of a C-terminal protonated Lys followed by a 19-Ala α-helix with a 20th Ala-like unit whose side chain is linked by a disulfide bond to a corresponding Ala-like unit connected to a second 19-Ala α-helix terminated by a second C-terminal-protonated Lys. The Coulomb potentials arising from the two charged Lys residues and dipole potentials arising from the two oppositely directed 72 D dipoles of the α-helices act to stabilize the SS bond's σ* orbital. The Coulomb potentials provide stabilization of 1 eV, while the two large dipoles generate an additional 4 eV. Such stabilization allows the SS σ* orbital to attach an electron and thereby generate disulfide bond cleavage products. Although calculations are performed only on SS bond cleavage, discussion of N-C(α) bond cleavage caused by electron attachment to amide π* orbitals is also presented. The magnitudes of the stabilization energies as well as the fact that they arise from Coulomb and dipole potentials are supported by results on a small model system consisting of a H(3)C-SS-CH(3) molecule with positive and negative fractional point charges to its left and right designed to represent (i) two positive charges ca. 32 Å distant (i.e., the two charged Lys sites of the peptide model) and (ii) two 72 D dipoles (i.e., the two α-helices). Earlier workers suggested that internal dipole forces in polypeptides could act to guide incoming free electrons (i.e., in electron capture dissociation (ECD)) toward the positive end of the dipole and thus affect the branching ratios for cleaving various bonds. Those workers argued that, because of the huge mass difference between an anion donor and a free electron, internal dipole forces would have a far smaller influence over the trajectory of a donor (i.e., in electron transfer dissociation

[Suicide among the French National Police forces: Implication of life events and life trajectories].

Science.gov (United States)

Encrenaz, G; Miras, A; Contrand, B; Séguin, M; Moulki, M; Queinec, R; René, J-S; Fériot, A; Mougin, M; Bonfils, M; Marien, P; Michel, G; Lagarde, E

2016-08-01

Research indicates that suicide rates are high among members of law enforcement. Our objectives were: (1) to determine life events implicated in suicide mortality among French law enforcement; and (2) to describe the different life trajectories of police officers who deceased by suicide. All suicides of police officers which occurred during 2008 (n=49) were explored using the psychological autopsy method. Key informants were: a supervisor, a colleague and a member of the family or a close friend. Each of them were interviewed by trained psychologists using standardized questionnaires exploring: sociodemographic characteristics, life events, social integration and support, health service use, mental health with the Composite International Diagnostic Interview short form (CIDI-SF), occupational stress with the Spielberger Inventory, impulsiveness with the Barratt Impulsiveness Scale and aggressiveness with the Brown-Goodwin Lifetime Aggression Scale. Information was then summarized in a timetable life trajectory of all life areas. All cases were finally appraised by at least two experts in order to identify the determinants of the suicide and to determine psychiatric diagnoses. For each period of time, a burdensomeness score was determined, from 6 (no adversity) to 1 (adversities in each sphere of life). Of the 49 cases of suicide, two were excluded and 39 were investigated and appraised (response rate: 39/47=83%). Eighty-two percent of the suicide cases were men and the mean age at death was 35years. In more than half of the cases, police officers used their service weapon to commit suicide. All deceased police officers were suffering from mental health symptoms (primarily depression). Of them, two thirds had used healthcare for this distress. The main other cause of suicide was problems in the married life (70% of the cases). Four distinct types of life trajectories of adversities could be identified by a qualitative analysis. It is the first time such a study was

Mathematical modelling for trajectories of magnetic nanoparticles in a blood vessel under magnetic field

International Nuclear Information System (INIS)

Sharma, Shashi; Katiyar, V.K.; Singh, Uaday

2015-01-01

A mathematical model is developed to describe the trajectories of a cluster of magnetic nanoparticles in a blood vessel for the application of magnetic drug targeting (MDT). The magnetic nanoparticles are injected into a blood vessel upstream from a malignant tissue and are captured at the tumour site with help of an applied magnetic field. The applied field is produced by a rare earth cylindrical magnet positioned outside the body. All forces expected to significantly affect the transport of nanoparticles were incorporated, including magnetization force, drag force and buoyancy force. The results show that particles are slow down and captured under the influence of magnetic force, which is responsible to attract the magnetic particles towards the magnet. It is optimized that all particles are captured either before or at the centre of the magnet (z≤0) when blood vessel is very close proximity to the magnet (d=2.5 cm). However, as the distance between blood vessel and magnet (d) increases (above 4.5 cm), the magnetic nanoparticles particles become free and they flow away down the blood vessel. Further, the present model results are validated by the simulations performed using the finite element based COMSOL software. - Highlights: • A mathematical model is developed to describe the trajectories of magnetic nanoparticles. • The dominant magnetic, drag and buoyancy forces are considered. • All particles are captured when distance between blood vessel and magnet (d) is up to 4.5 cm. • Further increase in d value (above 4.5 cm) results the free movement of magnetic particles

Production process of the synthetics fuels: technological trajectory analysis; Processos de producao de combustiveis sinteticos: analise das trajetorias tecnologicas

Energy Technology Data Exchange (ETDEWEB)

Dunham, Fabricio B. [Financiadora de Estudos e Projectos (FINEP), Rio de Janeiro, RJ (Brazil)]. E-mail: fbrollo@finep.gov.br; Bomtempo, Jose Vitor [Universidade Federal, Rio de Janeiro, RJ (Brazil). Escola de Quimica]. E-mail: vitor@eq.ufrj.br; Almeida, Edmar Luiz F. de

2003-07-01

This paper describes the evolution of the technological trajectories on synthetic fuels. What has influenced on the development of the first production process during the Second World War was analyzed, as well as, the causes of the first technological trajectory ending. It also shows the reasons of returning of the Fischer-Tropsch process to the petroleum companies' and technology licensors' R and D programs. At last, the consequences of the new technological trajectory and its differences regarding to the previous one were analyzed. (author)

Multipoles and Force on External Points for a Two-layered Spheroidal Liquid Mass Rotating Differentialy

Energy Technology Data Exchange (ETDEWEB)

Cisneros-Parra, Joel U. [Facultad de Ciencias, UASLP, Zona Universitaria, San Luis Potosi, S,L,P, 78290 (Mexico); Martinez-Herrera, Francisco J.; Montalvo-Castro, J. Daniel [Instituto de Fisica, UASLP, Zona Universitaria, San Luis Potosi, S,L,P, 78290 (Mexico)

2017-10-20

We recently reported on a series of equilibrium figures for a self-gravitating heterogeneous liquid body, consisting of two concentric distorted spheroids, “nucleus” and “atmosphere,” each endowed with its own internal motion of differential rotation. In our current work, we calculate the body’s force at external points and obtain a multipolar expansion of the potential. We also give an account of figures with prolate nuclei, which remained unnoticed by us in our former paper.

Multipoles and Force on External Points for a Two-layered Spheroidal Liquid Mass Rotating Differentialy

International Nuclear Information System (INIS)

Cisneros-Parra, Joel U.; Martinez-Herrera, Francisco J.; Montalvo-Castro, J. Daniel

2017-01-01

We recently reported on a series of equilibrium figures for a self-gravitating heterogeneous liquid body, consisting of two concentric distorted spheroids, “nucleus” and “atmosphere,” each endowed with its own internal motion of differential rotation. In our current work, we calculate the body’s force at external points and obtain a multipolar expansion of the potential. We also give an account of figures with prolate nuclei, which remained unnoticed by us in our former paper.

Development of method for experimental determination of wheel–rail contact forces and contact point position by using instrumented wheelset

International Nuclear Information System (INIS)

Bižić, Milan B; Petrović, Dragan Z; Tomić, Miloš C; Djinović, Zoran V

2017-01-01

This paper presents the development of a unique method for experimental determination of wheel–rail contact forces and contact point position by using the instrumented wheelset (IWS). Solutions of key problems in the development of IWS are proposed, such as the determination of optimal locations, layout, number and way of connecting strain gauges as well as the development of an inverse identification algorithm (IIA). The base for the solution of these problems is the wheel model and results of FEM calculations, while IIA is based on the method of blind source separation using independent component analysis. In the first phase, the developed method was tested on a wheel model and a high accuracy was obtained (deviations of parameters obtained with IIA and really applied parameters in the model are less than 2%). In the second phase, experimental tests on the real object or IWS were carried out. The signal-to-noise ratio was identified as the main influential parameter on the measurement accuracy. Тhе obtained results have shown that the developed method enables measurement of vertical and lateral wheel–rail contact forces Q and Y and their ratio Y / Q with estimated errors of less than 10%, while the estimated measurement error of contact point position is less than 15%. At flange contact and higher values of ratio Y / Q or Y force, the measurement errors are reduced, which is extremely important for the reliability and quality of experimental tests of safety against derailment of railway vehicles according to the standards UIC 518 and EN 14363. The obtained results have shown that the proposed method can be successfully applied in solving the problem of high accuracy measurement of wheel–rail contact forces and contact point position using IWS. (paper)

Geometrical properties of systems with spiral trajectories in R^3

Directory of Open Access Journals (Sweden)

Luka Korkut

2015-10-01

Full Text Available We study a class of second-order nonautonomous differential equations, and the corresponding planar and spatial systems, from the geometrical point of view. The oscillatory behavior of solutions at infinity is measured by oscillatory and phase dimensions, The oscillatory dimension is defined as the box dimension of the reflected solution near the origin, while the phase dimension is defined as the box dimension of a trajectory of the planar system in the phase plane. Using the phase dimension of the second-order equation we compute the box dimension of a spiral trajectory of the spatial system. This phase dimension of the second-order equation is connected to the asymptotic of the associated Poincare map. Also, the box dimension of a trajectory of the reduced normal form with one eigenvalue equals zero, and a pair of pure imaginary eigenvalues is computed when limit cycles bifurcate from the origin.

The trajectory of hope: pathways to find meaning and reconstructing the self after a spinal cord injury.

Science.gov (United States)

Parashar, D

2015-07-01

This is a qualitative study. To evaluate and track the importance and the continuum of hope, and its trajectory, from the point of view of the individual with a spinal cord injury (SCI) and a rehabilitation psychologist. This study was conducted in the Indian Spinal Injuries Centre, New Delhi, India, and in patients' homes in the National Capital Region, India. Twenty individuals with an SCI were interviewed for the study at intervals of 2 weeks, 6 months, 1 year and 2 years since the time of the injury. Semi-structured interviews were conducted, in which the following theoretical research questions were investigated: 'What is the meaning, relevance and significance of hope in the individual's life following an SCI? Does the meaning and subject of hope change at different points in time?' Three distinctive themes markedly emerged in the trajectory of hope: (1) Hope for a complete recovery; (2) hope for self-reliance despite the injury; and (3) hope for an optimum quality of life. The make-up of each theme, its significance and contribution to recovery and/or rehabilitation, while tracking the influence of time since injury, family and friends, as well as other agencies and pathways, are discussed. After sustaining a life-altering injury, hope becomes the force that spurs individuals. Psychologists and rehabilitation counselors need to focus on instilling realistic hope, goal setting, sustaining motivation, enabling adaptive appraisals and problem-solving. Further recommendations include developing and testing interventions against the context of the continuum of hope.

Predicting the outcome of oral food challenges with hen's egg through skin test end-point titration.

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Tripodi, S; Businco, A Di Rienzo; Alessandri, C; Panetta, V; Restani, P; Matricardi, P M

2009-08-01

Oral food challenge (OFC) is the diagnostic 'gold standard' of food allergies but it is laborious and time consuming. Attempts to predict a positive OFC through specific IgE assays or conventional skin tests so far gave suboptimal results. To test whether skin test with titration curves predict with enough confidence the outcome of an oral food challenge. Children (n=47; mean age 6.2 +/- 4.2 years) with suspected and diagnosed allergic reactions to hen's egg (HE) were examined through clinical history, physical examination, oral food challenge, conventional and end-point titrated skin tests with HE white extract and determination of serum specific IgE against HE white. Predictive decision points for a positive outcome of food challenges were calculated through receiver operating characteristic (ROC) analysis for HE white using IgE concentration, weal size and end-point titration (EPT). OFC was positive (Sampson's score >or=3) in 20/47 children (42.5%). The area under the ROC curve obtained with the EPT method was significantly bigger than the one obtained by measuring IgE-specific antibodies (0.99 vs. 0.83, P<0.05) and weal size (0.99 vs. 0.88, P<0.05). The extract's dilution that successfully discriminated a positive from a negative OFC (sensitivity 95%, specificity 100%) was 1 : 256, corresponding to a concentration of 5.9 microg/mL of ovotransferrin, 22.2 microg/mL of ovalbumin, and 1.4 microg/mL of lysozyme. EPT is a promising approach to optimize the use of skin prick tests and to predict the outcome of OFC with HE in children. Further studies are needed to test whether this encouraging finding can be extended to other populations and food allergens.

A clamping force measurement system for monitoring the condition of bolted joints on railway track joints and points

International Nuclear Information System (INIS)

Tesfa, B; Horler, G; Thobiani, F Al; Gu, F; Ball, A D

2012-01-01

Many industrial structures associated with railway infrastructures rely on a large number of bolted joint connections to ensure safe and reliable operation of the track and trackside furniture. Significant sums of money are spent annually to repair the damage caused by bolt failures and to maintain the integrity of bolted structures. In the UK, Network Rail (the organization responsible for rail network maintenance and safety) conducts corrective and preventive maintenance manually on 26,000 sets of points (each having approximately 30 bolted joints per set), in order to ensure operational success and safety for the travelling public. Such manual maintenance is costly, disruptive, unreliable and prone to human error. The aim of this work is to provide a means of automatically measuring the clamping force of each individual bolted joint, by means of an instrumented washer. This paper describes the development of a sensor means to be used in the washer, which satisfies the following criteria. 1. Sense changes in the clamping force of the joint and report this fact. 2. Provide compatibility with the large dynamic range of clamping force. 3. Satisfy the limitations in terms of physical size. 4. Provide the means to electronically interface with the washer. 5. Provide a means of powering the washer in situ. 6. Provide a solution at an acceptable cost. Specifically the paper focuses on requirements 1, 2 and 3 and presents the results that support further development of the proposed design and the realization of a pre-prototype system. In the paper, various options for the force sensing element (strain gage, capacitor, piezo-resistive) have been compared, using design optimization techniques. As a result of the evaluation, piezo-resistive sensors in concert with a proprietary force attenuation method, have been found to offer the best performance and cost trade-off The performance of the novel clamping force sensor has been evaluated experimentally and the results show

Three-dimensional trajectory tracking for underactuated AUVs with bio-inspired velocity regulation

Directory of Open Access Journals (Sweden)

Jiajia Zhou

2018-05-01

Full Text Available This paper attempts to address the motion parameter skip problem associated with three-dimensional trajectory tracking of an underactuated Autonomous Underwater Vehicle (AUV using backstepping-based control, due to the unsmoothness of tracking trajectory. Through kinematics concepts, a three-dimensional dynamic velocity regulation controller is derived. This controller makes use of the surge and angular velocity errors with bio-inspired models and backstepping techniques. It overcomes the frequently occurring problem of parameter skip at inflection point existing in backstepping tracking control method and increases system robustness. Moreover, the proposed method can effectively avoid the singularity problem in backstepping control of virtual velocity error. The control system is proved to be uniformly ultimately bounded using Lyapunov stability theory. Simulation results illustrate the effectiveness and efficiency of the developed controller, which can realize accurate three-dimensional trajectory tracking for an underactuated AUV with constant external disturbances. Keywords: Dynamic velocity regulation, Bio-inspired model, Backstepping, Underactuated AUV, Three-dimensional trajectory tracking

Social adversity in pregnancy and trajectories of women's depressive symptoms: A longitudinal study.

Science.gov (United States)

Kingsbury, Ann M; Plotnikova, Maria; Clavarino, Alexandra; Mamun, Abullah; Najman, Jake M

2018-02-01

Sound evidence has linked the experience of adversity with depression. Less is known about this association over time. The aim of this study is to determine whether or not social adversity experienced by pregnant women is associated with their patterns of depressive symptoms over their reproductive life course. Data were obtained from a cohort of women collected at their first obstetrical clinic visit of an index pregnancy (time-point 1) and at a further six time-points to 27 years following the birth. Latent Class Growth Modelling was used to estimate trajectories of women's depressive symptoms over this time period. Logistic regression modelling determined the prospective association between measures of adversity in pregnancy and 27-year postpartum depression trajectories, controlling for potential confounders. Experiencing financial problems, housing problems, serious disagreements with partners and with others, and experiencing serious health problems in pregnancy were associated with membership of high and middle depression trajectories over the 27 years. Having someone close die or have a serious illness was associated with the high depression trajectory only. Younger maternal age and low family-income at first clinic visit were also associated with an increased risk of women's membership of both high and middle depression trajectories. Experiencing adversity during pregnancy predicts subsequent patterns of maternal depression over an extended period of women's reproductive life course. It is not clear whether women's experiences of adversity during pregnancy were causally associated with subsequent depression or whether there are other explanations of the observed association. Copyright © 2017 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

Straight trajectory planning for keyhole neurosurgery in sheep with automatic brain structures segmentation

Science.gov (United States)

Favaro, Alberto; Lad, Akash; Formenti, Davide; Zani, Davide Danilo; De Momi, Elena

2017-03-01

In a translational neuroscience/neurosurgery perspective, sheep are considered good candidates to study because of the similarity between their brain and the human one. Automatic planning systems for safe keyhole neurosurgery maximize the probe/catheter distance from vessels and risky structures. This work consists in the development of a trajectories planner for straight catheters placement intended to be used for investigating the drug diffusivity mechanisms in sheep brain. Automatic brain segmentation of gray matter, white matter and cerebrospinal fluid is achieved using an online available sheep atlas. Ventricles, midbrain and cerebellum segmentation have been also carried out. The veterinary surgeon is asked to select a target point within the white matter to be reached by the probe and to define an entry area on the brain cortex. To mitigate the risk of hemorrhage during the insertion process, which can prevent the success of the insertion procedure, the trajectory planner performs a curvature analysis of the brain cortex and wipes out from the poll of possible entry points the sulci, as part of brain cortex where superficial blood vessels are naturally located. A limited set of trajectories is then computed and presented to the surgeon, satisfying an optimality criteria based on a cost function which considers the distance from critical brain areas and the whole trajectory length. The planner proved to be effective in defining rectilinear trajectories accounting for the safety constraints determined by the brain morphology. It also demonstrated a short computational time and good capability in segmenting gyri and sulci surfaces.

Automated trajectory planning for multiple-flyby interplanetary missions

Science.gov (United States)

Englander, Jacob

-loop optimization algorithm cannot require any a priori information and must always return a solution. In addition, the upper and lower bounds on each decision variable cannot be chosen a priori by the user because the user has no way to know what problem will be solved. Instead a method of choosing upper and lower bounds via a set of simple rules was developed and used for all three types of trajectory optimization problem. Many optimization algorithms were tested and discarded until suitable algorithms were found for each type of trajectory. The first class of trajectories use chemical propulsion and may only apply a ▵v at the periapse of each flyby. These Multiple Gravity Assist (MGA) trajectories are optimized using a cooperative algorithm of Differential Evolution (DE) and Particle Swarm Optimization (PSO). The second class of trajectories, known as Multiple Gravity Assist with one Deep Space Maneuver (MGA-DSM), also use chemical propulsion but instead of maneuvering at the periapse of each flyby as in the MGA case a maneuver is applied at a free point along each planet-to-planet arc, i.e. there is one maneuver for each pair of flybys. MGA-DSM trajectories are parameterized by more variables than MGA trajectories, and so the cooperative algorithm of DE and PSO that was used to optimize MGA trajectories was found to be less effective when applied to MGA-DSM. Instead, either PSO or DE alone were found to be more effective. The third class of trajectories addressed in this work are those using continuousthrust propulsion. Continuous-thrust trajectory optimization problems are more challenging than impulsive-thrust problems because the control variables are a continuous time series rather than a small set of parameters and because the spacecraft does not follow a conic section trajectory, leading to a large number of nonlinear constraints that must be satisfied to ensure that the spacecraft obeys the equations of motion. Many models and optimization algorithms were applied

Accurately tracking single-cell movement trajectories in microfluidic cell sorting devices.

Science.gov (United States)

Jeong, Jenny; Frohberg, Nicholas J; Zhou, Enlu; Sulchek, Todd; Qiu, Peng

2018-01-01

Microfluidics are routinely used to study cellular properties, including the efficient quantification of single-cell biomechanics and label-free cell sorting based on the biomechanical properties, such as elasticity, viscosity, stiffness, and adhesion. Both quantification and sorting applications require optimal design of the microfluidic devices and mathematical modeling of the interactions between cells, fluid, and the channel of the device. As a first step toward building such a mathematical model, we collected video recordings of cells moving through a ridged microfluidic channel designed to compress and redirect cells according to cell biomechanics. We developed an efficient algorithm that automatically and accurately tracked the cell trajectories in the recordings. We tested the algorithm on recordings of cells with different stiffness, and showed the correlation between cell stiffness and the tracked trajectories. Moreover, the tracking algorithm successfully picked up subtle differences of cell motion when passing through consecutive ridges. The algorithm for accurately tracking cell trajectories paves the way for future efforts of modeling the flow, forces, and dynamics of cell properties in microfluidics applications.

Accurately tracking single-cell movement trajectories in microfluidic cell sorting devices.

Directory of Open Access Journals (Sweden)

Jenny Jeong

Full Text Available Microfluidics are routinely used to study cellular properties, including the efficient quantification of single-cell biomechanics and label-free cell sorting based on the biomechanical properties, such as elasticity, viscosity, stiffness, and adhesion. Both quantification and sorting applications require optimal design of the microfluidic devices and mathematical modeling of the interactions between cells, fluid, and the channel of the device. As a first step toward building such a mathematical model, we collected video recordings of cells moving through a ridged microfluidic channel designed to compress and redirect cells according to cell biomechanics. We developed an efficient algorithm that automatically and accurately tracked the cell trajectories in the recordings. We tested the algorithm on recordings of cells with different stiffness, and showed the correlation between cell stiffness and the tracked trajectories. Moreover, the tracking algorithm successfully picked up subtle differences of cell motion when passing through consecutive ridges. The algorithm for accurately tracking cell trajectories paves the way for future efforts of modeling the flow, forces, and dynamics of cell properties in microfluidics applications.

Optimal bounds and extremal trajectories for time averages in dynamical systems

Science.gov (United States)

Tobasco, Ian; Goluskin, David; Doering, Charles

2017-11-01

For systems governed by differential equations it is natural to seek extremal solution trajectories, maximizing or minimizing the long-time average of a given quantity of interest. A priori bounds on optima can be proved by constructing auxiliary functions satisfying certain point-wise inequalities, the verification of which does not require solving the underlying equations. We prove that for any bounded autonomous ODE, the problems of finding extremal trajectories on the one hand and optimal auxiliary functions on the other are strongly dual in the sense of convex duality. As a result, auxiliary functions provide arbitrarily sharp bounds on optimal time averages. Furthermore, nearly optimal auxiliary functions provide volumes in phase space where maximal and nearly maximal trajectories must lie. For polynomial systems, such functions can be constructed by semidefinite programming. We illustrate these ideas using the Lorenz system, producing explicit volumes in phase space where extremal trajectories are guaranteed to reside. Supported by NSF Award DMS-1515161, Van Loo Postdoctoral Fellowships, and the John Simon Guggenheim Foundation.

Method of interplanetary trajectory optimization for the spacecraft with low thrust and swing-bys

Science.gov (United States)

Konstantinov, M. S.; Thein, M.

2017-07-01

The method developed to avoid the complexity of solving the multipoint boundary value problem while optimizing interplanetary trajectories of the spacecraft with electric propulsion and a sequence of swing-bys is presented in the paper. This method is based on the use of the preliminary problem solutions for the impulsive trajectories. The preliminary problem analyzed at the first stage of the study is formulated so that the analysis and optimization of a particular flight path is considered as the unconstrained minimum in the space of the selectable parameters. The existing methods can effectively solve this problem and make it possible to identify rational flight paths (the sequence of swing-bys) to receive the initial approximation for the main characteristics of the flight path (dates, values of the hyperbolic excess velocity, etc.). These characteristics can be used to optimize the trajectory of the spacecraft with electric propulsion. The special feature of the work is the introduction of the second (intermediate) stage of the research. At this stage some characteristics of the analyzed flight path (e.g. dates of swing-bys) are fixed and the problem is formulated so that the trajectory of the spacecraft with electric propulsion is optimized on selected sites of the flight path. The end-to-end optimization is carried out at the third (final) stage of the research. The distinctive feature of this stage is the analysis of the full set of optimal conditions for the considered flight path. The analysis of the characteristics of the optimal flight trajectories to Jupiter with Earth, Venus and Mars swing-bys for the spacecraft with electric propulsion are presented. The paper shows that the spacecraft weighing more than 7150 kg can be delivered into the vicinity of Jupiter along the trajectory with two Earth swing-bys by use of the space transportation system based on the "Angara A5" rocket launcher, the chemical upper stage "KVTK" and the electric propulsion system

Depressed trajectory SLBMs: A technical evaluation and arms control possibilities

International Nuclear Information System (INIS)

Gronlund, L.; Wright, D.C.

1992-01-01

SLBMs (sea-launched ballistic missiles) flown on depressed trajectories would have short flight times, comparable to escape times of bombers and launch times of ICBMs, thus raising the possibility of short time-of-flight (STOF) nuclear attacks. We assess the depressed trajectory (DT) capability of existing SLBMs by calculating the flight times, atmospheric loading on the booster, reentry heating on the reentry vehicle (RV), and degradation of accuracy for a DT SLBM. We find that current US and CIS SLBMs flown on depressed trajectories would have the capability to attack bomber bases at ranges of up to about 2,000 kilometers, and possibly at ranges up to 3,000 kilometers. To target bombers based furthest inland, a new high-velocity booster might be required, and attacking hardened targets would require a maneuvering RV (MaRV). We conclude that DT capabilities could be effectively controlled by the combination of an apogee restriction on the flight testing of existing SLBMs and bans on the development of high-velocity boosters and MaRVs, and that, in view of their inherent STOF capabilities, deep cuts in the number of SLBMs or their elimination might be desirable for an optimal minimum-deterrent force structure

Examining the Weight Trajectory of College Students.

Science.gov (United States)

Pope, Lizzy; Hansen, Danielle; Harvey, Jean

2017-02-01

To examine the weight trajectory of students over 4 years of college. Anthropometric assessments were completed at the beginning and end of students' freshman year and the end of senior year to calculate body mass index. Questionnaires assessing weight-related behaviors were completed in senior year. Of the original 117 students, 86 remained in the study for 4 years. Body mass index was significantly higher at the end of senior year (mean, 24.84; SD, 4.46) vs the beginning of freshman year (mean, 23.59; SD, 4.01; t[85] = 5.61; P Students' mean weight gain was 4.38 kg and the sample increased from 23% to 41% overweight/obese. No significant associations were found between BMI and lifestyle factors. This study suggests that students gain weight throughout college, which highlights the need for weight control interventions to target more than just freshman college students. Copyright © 2016 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

Imaging ballistic carrier trajectories in graphene using scanning gate microscopy