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The measurement of similarity between two motion trajectories is one of the fundamental task for motion analysis, perception and recognition. Previous research focus on 2D trajectory similarity measurement. With the advent of 3D sensors, it is possible to collect large amounts of 3D trajectory data for more precise motion representation. As trajectories in 3D space may often exhibit a similar motion pattern but may differ in location, orientation, scale, and appearance variations, the trajectory descriptor must be invariant to these degrees of freedom. Shape context is one of the rich local shape descriptors can be used to represent the trajectory in 2D space, however, rarely applied in the 3D motion trajectory recognition field. To handle 3D data, in this paper, we first naturally extend the shape context into the spatiotemporal domain by adopting a spherical neighborhood, and named it 3D Shape Context(3DSC). To achieve better global invariant on trajectories classification, the adaptive outer radius of 3DSC for extracting 3D Shape Context feature is proposed. The advantages of our proposed 3D shape context are: (1) It is invariant to motion trajectories translation and scale in the spatiotemporal domain; (2) It contains the whole trajectory points in the 3DSC ball volume, thus can achieve global information representation and is good for solving sub-trajectories problem; (3) It is insensitive to the appearance variations in the identical meaning trajectories, meanwhile, can greatly discriminate the distinct meaning trajectories. In trajectory recognition phase, we consider a feature-to-feature alignment between motion trajectories based on dynamic time warping and then use the one nearest neighbor (1NN) classifier for final accuracy evaluation. We test the performance of proposed 3D SC-DTW on UCI ASL large dataset, Digital hand dataset and the experimental results demonstrate the effectiveness of our method. [ABSTRACT FROM AUTHOR]

Background: Similar types of trajectory patterns have been identified by Latent Class Analyses (LCA) across multiple low back pain (LBP) cohorts, but these patterns are impractical to apply to new cohorts or individual patients. It would be useful to be able to identify trajectory subgroups from descriptive definitions, as a way to apply the same definitions of mutually exclusive subgroups across populations. In this study, we investigated if the course trajectories of two LBP cohorts fitted with previously suggested trajectory subgroup definitions, how distinctly different these subgroups were, and if the subgroup definitions matched with LCA-derived patterns.Methods: Weekly measures of LBP intensity and frequency during 1 year were available from two clinical cohorts. We applied definitions of 16 possible trajectory subgroups to these observations and calculated the prevalence of the subgroups. The probability of belonging to each of eight LCA-derived patterns was determined within each subgroup. LBP intensity and frequency were described within subgroups and the subgroups of 'fluctuating' and 'episodic' LBP were compared on clinical characteristics.Results: All of 1077 observed trajectories fitted with the defined subgroups. 'Severe episodic LBP' was the most frequent pattern in both cohorts and 'ongoing LBP' was almost non-existing. There was a clear relationship between the defined trajectory subgroups and LCA-derived trajectory patterns, as in most subgroups, all patients had high probabilities of belonging to only one or two of the LCA patterns. The characteristics of the six defined subgroups with minor LBP were very similar. 'Fluctuating LBP' subgroups were significantly more distressed, had more intense leg pain, higher levels of activity limitation, and more negative expectations about future LBP than 'episodic LBP' subgroups.Conclusion: Previously suggested definitions of LBP trajectory subgroups could be readily applied to patients' observed data resulting in subgroups that matched well with LCA-derived trajectory patterns. We suggest that the number of trajectory subgroups can be reduced by merging some subgroups with minor LBP. Stable levels of LBP were almost not observed and we suggest that minor fluctuations in pain intensity might be conceptualised as 'ongoing LBP'. Lastly, we found clear support for distinguishing between fluctuating and episodic LBP. [ABSTRACT FROM AUTHOR]

This study designs a training system for hand rehabilitation on the basis of augmented reality technology, which enables patients to simultaneously interact with real and virtual environments. The system framework is introduced, and four rehabilitation programs, namely, trajectory training, shelf training, batting training, and spile training, are presented. As a requirement of hand rehabilitation training, a color marker that is suitable for hand rehabilitation training is adopted. Following the Hamming coding principle, this marker is designed as a 7 × 7 square that is filled up by four designated colors with a binary bit of '0' or '1'. The check code in each row of the color marker is applied to restore the occluded binary bits, solve the occlusion issue of color markers, and complete the tracking registration of the color markers. The effectiveness of the developed system is evaluated via a usability study and questionnaires. The evaluation provides positive results. Therefore, the developed system has potential as an effective rehabilitation system for upper limb impairment. [ABSTRACT FROM AUTHOR]

The circular-arc trajectory on inclined the plane is one of the models for the orbit design of directional drilling. The key issue of the design and control for the circular-arc trajectory is how to judge the theoretical calculated values of the targethitting azimuth and tool face angle, because the target-hitting azimuth and tool face angle toward targets of 3D directional well may exist in four quadrants of 0° ~ 360°. Based on the spatial geometric model of the circular-arc trajectory on the inclined plane, a new evaluation method of target azimuth change is proposed according to coordinates of the target relative to the horizontal projection of two lines' intersection. These two lines are tangents at the starting and ending points of the complete build-up curve section respectively. Therefore, the analytic expression of a criterion for target azimuth change in the deflecting section is obtained. For control of circular-arc trajectory, a judgmental method of the tool face angle is also discussed in the paper, and its criterion is worked out using quadrant overlap of the value calculated by two formulas of tool face angle. The practical engineering cases have demonstrated that the new evaluation methods of the target azimuth and the tool face angle are effective. And the trajectory data of back calculation shows high accuracy to hit the target. Compared with traditional evaluation modes, the methods proposed in this paper avoid the ambiguity of 0° azimuth and the partial increase of tool face angle. Simultaneously they can be applied directly in practical project as well as algorithm of directional drilling software. [ABSTRACT FROM AUTHOR]

Background: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is now a key treatment choice for advanced Parkinson's disease. The optimum target area within the STN is well established. However, no emphasis on the impact of trajectory exists. The ellipsoid shape of the STN and the off-centre traditional target point mean that variation in the electrode inclination should affect STN engagement. Understanding of this relationship could inform trajectory selection during planning by improving STN engagements and margins for error. Method: We simulated electrode placement at the clinical target through a set of trial trajectories. Twelve three-dimensionally reconstructed STNs were created from magnetic resonance imaging data of six patients. An appropriate target within each STN was then chosen. Each STN was approached through 56 simulated trajectories arranged in a grid covering a quadrant of skull around and in front of the coronal suture. A subset of 20 viable trajectories was reassessed for depth of engagement in each STN whilst approaching the chosen target. Results: Group averages for each trajectory are presented as traffic light maps and as an overlaid skull mask illustrating recommended electrode entry sites. Trajectories under 30 degrees anterior to the bregma and between 10 to 30 degrees off the midline accommodated over 2.4 degrees of wobble. A mean engagement of 6 mm was possible in half of the subset. The longest engagements are on trajectories which saddle the coronal suture, extending to 40 degrees lateral. Microelectrode tracts of 14 additional STNs were collated using the above protocol and engagement exceeded 5 mm in all central trajectories without capsular side effects, suggesting placement away from STN borders. Conclusions: Trajectory selection influences engagement and flexibility to accommodate electrode wobble or brain shift whilst approaching a chosen STN target. We recommend having the first trial trajectory 20 degrees anterior to the bregma, moving postero-laterally in successive trials to balance both error and engagement. When wider margins for error are beneficial (e.g. second side during bilateral procedures), trajectories nearer the coronal suture and around 25 degrees off the midline are advised. [ABSTRACT FROM AUTHOR]

We consider the damped and driven two-dimensional Euler equations in the plane with weak solutions having finite energy and enstrophy. We show that these (possibly non-unique) solutions satisfy the energy and enstrophy equality. It is shown that this system has a strong global and a strong trajectory attractor in the Sobolev space H1. A similar result on the strong attraction holds in the spaces H¹ ∩ {μ : || curl μ||LP < ∞ p ≥ 2. [ABSTRACT FROM AUTHOR]

This paper is concerned about the observability analysis of time-varying nonlinear dynamic model of a synchronous generator with its associated control systems. A byproduct of observability study is a set of guidelines to choose the appropriate set of measurements or sensors to be used to ensure strong observability for the dynamic states. The proposed analysis is developed using a Lie derivative based observability matrix and its singular values. A two-axis synchronous generator model and an associated IEEE-Type1 exciter are used to validate the results of observability analysis with dynamic simulations of disturbance scenarios using different types of measurements. It is shown that the dynamic state estimates will converge to the true trajectory faster and smoother if appropriate measurements that provide higher level of observability based on the proposed analysis are chosen. Results can be extended to other dynamic elements such as loads or time-varying parameters of machines. [ABSTRACT FROM AUTHOR]

Trajectory pattern mining is becoming increasingly popular because of the development of ubiquitous computing technology. Trajectory data contain abundant semantic and geographic information that reflects people's movement patterns, i.e., who is performing a certain type of activity when and where. However, the variety and complexity of people's movement activity and the large size of trajectory datasets make it difficult to mine valuable trajectory patterns. Moreover, most existing trajectory similarity measurements only consider a portion of the information contained in trajectory data. The patterns obtained cannot be interpreted well in terms of both semantic meaning and geographic distributions. As a result, these patterns cannot be used accurately for recommendation systems or other applications. This paper introduces a novel concept of the semantic-geographic pattern that considers both semantic and geographic meaning simultaneously. A flexible density-based clustering algorithm with a new trajectory similarity measurement called semantic intensity is used to mine these semantic-geographic patterns. Comparative experiments on check-in data from the Sina Weibo service demonstrate that semantic intensity can effectively measure both semantic and geographic similarities among trajectories. The resulting patterns are more accurate and easy to interpret. [ABSTRACT FROM AUTHOR]

In this paper, we present a method for autonomously detecting and extracting region(s)-of-interest (ROI) from surveillance videos using trajectory-based analysis. Our approach, localizes ROI in a stochastic manner using correlated probability density functions that model motion dynamics of multiple moving targets. The motion dynamics model is built by analyzing trajectories of multiple moving targets and associating importance to regions in the scene. The importance of each region is estimated as a function of the total time spent by multiple targets, their instantaneous velocity and direction of movement whilst passing through that region. We systematically validate our model and benchmark our technique against competing baselines through extensive experimentation using public datasets such as CAVIAR, ViSOR, and CUHK as well as a scenario-specific in-house surveillance dataset. Results obtained have demonstrated the superiority of the proposed technique against a few popular existing state-of-the-art techniques. [ABSTRACT FROM AUTHOR]

Spatial clustering can be used to discover hotspots in trajectory data. A trajectory clustering approach based on decision graph and data field is proposed as an effective method to select parameters for clustering, to determine the number of clusters, and to identify cluster centers. Synthetic data and real-world taxi trajectory data are utilized to demonstrate the effectiveness of the proposed approach. Results show that the proposed method can automatically determine the parameters for clustering as well as perform efficiently in trajectory clustering. Hotspots are identified and visualized during different times of a single day and at the same times on different days. The dynamic patterns of hotspots can be used to identify crowded areas and events, which are crucial for urban transportation planning and management. [ABSTRACT FROM PUBLISHER]

Autonomous, low-thrust guidance for active disposal of geosynchronous debris, subject to collision avoidance with the local debris population, is studied. A bisection method is employed to determine trajectory modifications to avoid a conjuncting debris object by a range of distances, assuming a range of collision lead times. A parametric study is performed, in which re-orbit thrust accelerations are varied from 10 to 10 m/s , to demonstrate how the continuous-thrust level impacts the required lead time to achieve a desired debris miss distance. The lowest thrust levels considered show that a 6-12 hour lead time is required to achieve a 1-10 km debris separation at the predicted collision time. [ABSTRACT FROM AUTHOR]

We study well-posedness of scalar conservation laws with moving ux constraints. In particular, we show the Lipschitz continuous dependence of BV solutions with respect to the initial data and the constraint trajectory. Applications to traffic ow theory are detailed. [ABSTRACT FROM AUTHOR]

Waves can be used to probe and image an unknown medium. Passive imaging uses ambient noise sources to illuminate the medium. This paper considers passive imaging with moving sensors. The motivation is to generate large synthetic apertures, which should result in enhanced resolution. However Doppler effects and lack of reciprocity significantly affect the imaging process. This paper discusses the consequences in terms of resolution and it shows how to design appropriate imaging functions depending on the sensor trajectory and velocity. [ABSTRACT FROM AUTHOR]

We study codimension 3 degenerate homoclinic bifurcations under periodic perturbations. Assume that among the 3 bifurcation equations, one is due to the homoclinic tangecy along the orbital direction. To the lowest order, the bifurcation equations become 3 quadratic equations. Under generic conditions on perturbations of the normal and tangential directions of the homoclinic orbit, up to 8 homoclinic orbits can be created through saddle-node bifurcations. Our results generate the homoclinic tangency bifurcation in Guckenheimer and Holmes [8]. [ABSTRACT FROM AUTHOR]

Collision efficiency, Pc, is one of the crucial quantitative characteristics of flow-induced coalescence, which consists in collisions of droplets dispersed in a flowing matrix followed by their fusion. The basic step of Pc estimation is the calculation of droplet pair trajectories from all possible start positions to find whether droplets fuse when they are in a given start position. The trajectories can be calculated by exact solution of equations expressing the change of all coordinates with time for Newtonian systems. Since involving of viscoelastic properties into this exact description appeared difficult, we used simplifications and approximations. However, the approximations were too gross and lead to inconsistencies for some systems. To find such approximations level that avoids inconsistencies but still allows us to reach the solution, we decided to evaluate and demonstrate effects of individual approximations. Comparison made on a Newtonian system has shown that neglecting of parameters dependence on viscosity ratio and droplet size ratio has not critical consequences for spherical droplets. However, the abandonment of the switch between free-flow and near-approach approximations, and involving of the reliable description of hydrodynamic interaction for broader range of inter-droplet distances should be considered. [ABSTRACT FROM AUTHOR]

SUMMARY We developed a leg extender exoskeleton that extends leg length by 40 cm. We also propose a linearity index to evaluate the feeling of operating the exoskeleton. We developed an evaluation method for the foot positioning accuracy of the leg extender exoskeleton. This method uses three types of target marker trajectories to consider various walking situations. We performed a real-world experiment using four types of link configurations. The foot positioning accuracy was measured and evaluated according to the linearity index for each exoskeleton. The results showed that an exoskeleton with good linearity provides better foot positioning accuracy. [ABSTRACT FROM AUTHOR]

Background: Maternal nutritional status is a key determinant of small for gestational age (SGA), but some knowledge gaps remain, particularly regarding the role of the energy balance entering pregnancy. Objective: We investigated how preconceptional and gestational weight trajectories (summarized by individual-level traits) are associated with SGA risk in rural Gambia. Design: The sample comprised 670 women in a trial with serial weight data (7310 observations) that were available before and during pregnancy. Individual trajectories from 6 mo before conception to 30 wk of gestation were produced with the use of multilevel modeling. Summary traits were expressed as weight z scores [weight z score at 3 mo preconception (zwt-3 mo), weight z score at conception, weight z score at 3 mo postconception, weight z score at 7 mo post-conception (zwt+7 mo), and conditional measures that represented the change from the preceding time] and were related to SGA risk with the use of Poisson regression with confounder adjustment; linear splines were used to account for nonlinearity. Results: Maternal weight at each time point had a consistent nonlinear relation with SGA risk. For example, the zwt-3 mo estimate was stronger in women with values ≤0.5 (RR: 0.736; 95% CI: 0.594, 0.910) than in women with values >0.5 (RR: 0.920; 95% CI: 0.682, 1.241). The former group had the highest observed SGA prevalence. Focusing on weight change, only conditional zwt+7 mo was associated with SGA and only in women with values >-0.5 (RR: 0.579; 95% CI: 0.463, 0.724). Conclusions: Protection against delivering an SGA neonate offered by greater preconceptional or gestational weight may be most pronounced in more undernourished and vulnerable women. Independent of this possibility, greater second- and third-trimester weight gain beyond a threshold may be protective. This trial was registered at http://www.isrctn.com/ as ISRCTN49285450. [ABSTRACT FROM AUTHOR]

This paper presents a new high-speed object tracking algorithm and applies it in tracking high-speed golf balls. Several challenges are encountered in tracking this kind of small-size and high-speed objects; these challenges include: (1) the motion speed (up to 200km/h) of the object is extremely fast that the image captured by the camera can become easily blurred; (2) the size of the objects is small and there is not enough texture feature on the surface of the objects; (3) high-speed objects typically move in outdoor environments, which have complex backgrounds and the light conditions; and (4) a balance between robustness and real-time efficiency is difficult to achieve. There is no existing method can directly solve all these problems. To address these problems, a novel real-time visual tracking algorithm and system are developed that can realize high-speed small object tracking and trajectory predication. The frame difference method was employed to segment the moving objects from the background. The motion blurred object can be detected by applying the proposed object recognition method using multi-features (geometry features and object motion features). Different from the state of the art tracking algorithms, the motion blurring feature was also considered as a feature of the high-speed object, and the tracking robustness of the proposed algorithm does not rely on the texture feature of the tracking objects. To realize real-time efficiency, a region of interest predicting and updating method was proposed that can shrink the processing area of the frames and achieve a high frame rate. Combining visual servoing technology and aerodynamics, the trajectory of the high-speed object can be predicted. The high-speed golf ball tracking experiments were conducted to demonstrate the tracking efficiency and robustness of the algorithm. [ABSTRACT FROM AUTHOR]

Trajectory-based visualization of coordinated movement data within a bounded area, such as player and ball movement within a soccer pitch, can easily result in visual crossings, overplotting, and clutter. Trajectory abstraction can help to cope with these issues, but it is a challenging problem to select the right level of abstraction (LoA) for a given data set and analysis task. We present a novel dynamic approach that combines trajectory simplification and clustering techniques with the goal to support interpretation and understanding of movement patterns. Our technique provides smooth transitions between different abstraction types that can be computed dynamically and on-the-fly. This enables the analyst to effectively navigate and explore the space of possible abstractions in large trajectory data sets. Additionally, we provide a proof of concept for supporting the analyst in determining the LoA semi-automatically with a recommender system. Our approach is illustrated and evaluated by case studies, quantitative measures, and expert feedback. We further demonstrate that it allows analysts to solve a variety of analysis tasks in the domain of soccer. [ABSTRACT FROM AUTHOR]

Bundling techniques provide a visual simplification of a graph drawing or trail set, by spatially grouping similar graph edges or trails. This way, the structure of the visualization becomes simpler and thereby easier to comprehend in terms of assessing relations that are encoded by such paths, such as finding groups of strongly interrelated nodes in a graph, finding connections between spatial regions on a map linked by a number of vehicle trails, or discerning the motion structure of a set of objects by analyzing their paths. In this state of the art report, we aim to improve the understanding of graph and trail bundling via the following main contributions. First, we propose a data-based taxonomy that organizes bundling methods on the type of data they work on (graphs vs trails, which we refer to as paths). Based on a formal definition of path bundling, we propose a generic framework that describes the typical steps of all bundling algorithms in terms of high-level operations and show how existing method classes implement these steps. Next, we propose a description of tasks that bundling aims to address. Finally, we provide a wide set of example applications of bundling techniques and relate these to the above-mentioned taxonomies. Through these contributions, we aim to help both researchers and users to understand the bundling landscape as well as its technicalities. [ABSTRACT FROM AUTHOR]

Estimating models within the mixture model framework, like latent growth mixture modeling (LGMM) or latent class growth analysis (LCGA), involves making various decisions throughout the estimation process. This has led to a wide variety in how results of latent trajectory analysis are reported. To overcome this issue, using a 4-round Delphi study, we developed Guidelines for Reporting on Latent Trajectory Studies (GRoLTS). The purpose of GRoLTS is to present criteria that should be included when reporting the results of latent trajectory analysis across research fields. We have gone through a systematic process to identify key components that, according to a panel of experts, are necessary when reporting results for trajectory studies. We applied GRoLTS to 38 papers where LGMM or LCGA was used to study trajectories of posttraumatic stress after a traumatic event. [ABSTRACT FROM PUBLISHER]

Trajectory is a crucial part of exoskeleton robot design. The appropriate trajectory will affect wearer's safety, health and comfort. The trajectory profile of angular position can be generated as same as actual trajectory profile in term of shape. However, the problem of unreachable intermediate points increases the error between the polynomial trajectory profile and real human trajectory profile. This error directly can affect to generate a less accurate profile that can't be accurately matched to the human trajectory profile. Based on the aforementioned problem, the objectives of this paper is to investigate the effect of having a different number of sub-phases trajectories on the error related to the real human trajectory profile. Also, this paper presents trajectory generation method that is called quintic polynomial segment with 6th polynomial blend (6-5-6 PSPB). The 6-5-6 PSPB trajectory includes the via points at initial and final of each phase in order to solve the problem of unreachable intermediate points. The result shows a good improvement (almost 8%) in term of error based on the proposed 6-5-6 PSPB technique compared to the three categories of gait analysis. The 6-5-6 PSPB technique shows a good result based on the root mean square error (RMSE) and average difference (AD) error of angular position (0.3146 and 0.031310 Degree respectively). At the end, 6-5-6 PSPB can improve the error and generate a trajectory motion profile that accurately matches to human trajectory profile. [ABSTRACT FROM AUTHOR]

In this paper, a novel reaching law for discrete-time sliding-mode control is proposed. The reaching law is established based on an exponential term that dynamically adapts to the variation of the switching function. The difference function is also employed to redefine the change rate as the second-order difference of the disturbance. Unlike existing works, the proposed reaching law is able to guarantee smaller width of the quasi-sliding-mode domain (QSMD) while decreasing the reaching time in the same time. The ultimate magnitude of the QSMD in proposed method is of the order O(T3). Moreover, the reaching steps for the system to converge to the sliding surface are obtained and the system dynamics in and out the QSMD are theoretically analyzed. Both numerical simulations and experimental investigations on a piezoelectric actuator are employed to validate the effectiveness of the proposed method. [ABSTRACT FROM PUBLISHER]

Ambient air and soil samples were taken in Istanbul between November 2012 and May 2013 in order to determine polychlorinated biphenyl (PCB) concentrations. A high volume air sampler was operated to collect air samples. Soil samples were taken from top of bare land. Air PCB concentrations ranged from 201 to 705 pg m−3 with an average of 360 pg m−3. The dry weight soil PCB concentrations varied from 3.4 to 13.6 ng g−1 with an average of 8.3 ng g−1. The fate of PCBs was investigated through gas/particle partitioning. Further investigation was made between soil and air phases by fugacity fractions. Effect of wind direction was revealed by conditional probability function (CPF). Potential source contribution function was employed to determine the likely distant PCB sources. Di-chlorinated biphenyls (Di-CBs) tended to accumulate in soil while 5-, 7-, and 8-CBs volatilized from the soil. According to CPF, 3-CBs were likely to be released from the Marmara Sea. Additionally, SW wind direction was dominant for Σ-, 2-, 5-, 6-, 7-CBs, and concentration of 9-CBs increased for the winds of NW, N, NE directions. Previously reported hot-spot zones for iron-steel manufacturing industry were identified to contribute to PCBs in air masses, arriving from SW direction. Additional contribution was detected when air masses arrived from the north. These sources were from the south of the Ukraine. [ABSTRACT FROM AUTHOR]

The research of pedestrian tracking in infrared image sequences is a curial part of video surveillance. Considering the particular characteristics of the infrared image, such as low contrast, fuzzy edge and unknown noises interference, the study of infrared pedestrian tracking algorithm becomes a great challenge. Spatio-temporal slice method is effective due to considering both spatial and time scale. It can extract the trajectory of moving targets, reflecting the trajectory manifold variations of targets along the time, to provide ways to depict the regions of targets. However, traditional spatio-temporal based methods only consider the horizontal slice analysis and usually require a large amount of calculation time; this paper proposes a spatio-temporal tracking algorithm to infrared image sequences, using both horizontal and vertical multi-layer slices to obtain the integral trajectory manifold. The integral trajectory is analyzed to obtain the target boundary and position information, with which the target can be tracked in each frame. The experimental results show that the proposed method has a relatively high tracking accuracy with a fast computing speed. Moreover, it can perform effectively in different infrared image sequences with various motion modes by single pedestrian from OTCBVS/05 Terravic Motion IR Database. [ABSTRACT FROM AUTHOR]

In this paper, we document the results of the implementation of a series of activities related to an optimisation problem. The objective is describing how the construction of mathematical meanings is promoted when the students face the problem through different representations. The activities, addressed towards 15 year old students, surge from a free interpretation of the construct "Hypothetical Learning Trajectory" (HIT) by Simon (1995), considering different representations and utilising digital technologies. With this, we propose a route to tackle variation problems based on HLT similar to the proposed. [ABSTRACT FROM AUTHOR]

It is now confirmed that the Zhu–Nakamura (ZN) theory of nonadiabatic transition is useful to investigate various nonadiabatic chemical dynamics. The theory, being one-dimensional, presents a whole set of analytical formulas that enables us to treat the dynamics efficiently. It is also quite significant that classically forbidden transitions can be dealt with analytically. The theory can be combined with the trajectory surface hopping (TSH) method (ZN-TSH) and is demonstrated to be useful to clarify the dynamics of not only simple tri-atomic reactions but also large chemical systems. The whole set of analytical formulas directly applicable to practical systems is summarised and the applications to polyatomic systems are illustrated. Examples of polyatomic molecules are,, indolylmaleimide, cyclohexadiene (CHD), and retinal. The Fortran code for the whole set of ZN formulas is provided in Appendix for the convenience of a reader who is interested in using them. The ZN-TSH method can be combined with the QM/MM method to clarify reaction dynamics in the surrounding environment. This is named as ZN-QM/MM-TSH. The particle-mesh Ewald (PME) method can also be combined with ZN-TSH to clarify reaction dynamics in solutions. This is named as ZN-PME-TSH. Formulations of these methods are presented together with practical applications. Examples treated by ZN-QM/MM-TSH are photoisomerization dynamics of retinal chromophore embedded in the protein environment. The differences in the isomerization mechanisms between rhodopsin and isorhodopsin are made clear. The faster and more efficient isomerization of rhodopsin compared to isorhodopsin is nicely reproduced. Examples of reactions in solutions are photoisomerizations of retinal and CHD. The experimentally observed long life time of the excited state of retinal is reproduced and is found to be due to the long-range solvation effect. The solvent dependent branching ratios of CHD:hexatriene (HT) are clarified for the ethanol and hexane solvents by the ZN-PME-TSH method. Both ZN-QM/MM-TSH and ZN-PME-TSH are thus demonstrated to be promising methods to deal with a wide range of nonadiabatic dynamics in large chemical and biological systems. [ABSTRACT FROM AUTHOR]

This paper discusses the derivation and implementation of a nonlinear model predictive control law for tracking reference trajectories and constrained control of a quadrotor platform. The approach uses the state-dependent coefficient form to capture the system nonlinearities into a pseudo-linear system matrix. The state-dependent coefficient form is derived following a rigorous analysis of aerial vehicle dynamics that systematically accounts for the peculiarities of such systems. The same state-dependent coefficient form is exploited for obtaining a nonlinear equivalent of the model predictive control. The nonlinear model predictive control law is derived by first transforming the continuous system into a sampled-data form and and then using a sequential quadratic programming solver while accounting for input, output and state constraints. The boundedness of the tracking errors using the sampled-data implementation is shown explicitly. The performance of the nonlinear controller is illustrated through representative simulations showing the tracking of several aggressive reference trajectories with and without disturbances. [ABSTRACT FROM AUTHOR]

This work addresses the problem of the accurate task-space control subject to finite-time convergence. Dynamic equations of a redundant manipulator are assumed to be uncertain. Moreover, globally unbounded disturbances are allowed to act on the manipulator when tracking the trajectory by the end effector. Furthermore, the movement is to be accomplished in such a way as to optimize some performance index. Based on suitably defined task-space non-singular terminal sliding vector variable and the Lyapunov stability theory, we derive a class of inverse-free robust controllers consisting of a Jacobian transpose component plus a compensating term, which seem to be effective in counteracting uncertain dynamics, unbounded disturbances and (possible) kinematic singularities met on the robot trajectory. The numerical simulations carried out for a redundant manipulator of a Selective Compliant Articulated Robot for Assembly (SCARA) type consisting of three revolute kinematic pairs and operating in a two-dimensional task space illustrate performance of the proposed controllers. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

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Based on a validation of the numerical methods with an experiment, numerical simulations are carried out to study the effect of tip clearance size on the performance and tip leakage flow in a dual-stage counter-rotating axial compressor. The predicted results showed that the variation of the tip clearance size in rotor2 has a more significant impact on the overall performance and stall margin of the compressor. In addition, the impact of the tip clearance size effect is mainly on the rotor with the tip clearance size variation. The variation of the tip clearance size in rotor2 almost has no influence on the performance of rotor1, while the performance of rotor2 is increased about 1.37% at near-stall point when the tip clearance size of rotor1 is increased to 1.0 mm from 0.5 mm. At peak efficiency condition, the tip clearance size variation in rotor1 has remarkable influence on the tip leakage vortex intensity, onset point and trajectory in rotor1, but has little influence on those in rotor2. However, the tip clearance size variation in rotor2 has remarkable effect on those in both rotors. Different tip clearance size combination schemes can impact the stall-free characteristic in the counter-rotating axial compressor. [ABSTRACT FROM AUTHOR]

Unmanned Aerial Vehicles (UAVs) are used in different tasks with different flight path accuracy. To achieve a greater accuracy of flight trajectory GPS accuracy improvement methods are analyzed. The present article explains the main principles of GPS measurement. Precise Point Positioning (PPP) and Real-Time Kinematics (RTK) methods are described. and compared. Also, both methods have been tested. [ABSTRACT FROM PUBLISHER]

Fluid parcels can exchange water properties when coming into contact with each other, leading to mixing. The trajectory encounter mass and a related simplified quantity, the encounter volume, are introduced as a measure of the mixing potential of a flow. The encounter volume quantifies the volume of fluid that passes close to a reference trajectory over a finite time interval. Regions characterized by a low encounter volume, such as the cores of coherent eddies, have a low mixing potential, whereas turbulent or chaotic regions characterized by a large encounter volume have a high mixing potential. The encounter volume diagnostic is used to characterize the mixing potential in three flows of increasing complexity: the Duffing oscillator the Bickley jet and the altimetry-based velocity in the Gulf Stream extension region. An additional example is presented in which the encounter volume is combined with the u* approach of Pratt et al. (2016) to characterize the mixing potential for a specific tracer distribution in the Bickley jet flow. Analytical relationships are derived that connect the encounter volume to the shear and strain rates for linear shear and linear strain flows, respectively. It is shown that in both flows the encounter volume is proportional to time. [ABSTRACT FROM AUTHOR]

With the increasing use of mobile GPS (global positioning system) devices, a large volume of trajectory data on users can be produced. In most existing work, trajectories are usually divided into a set of stops and moves. In trajectories, stops represent the most important and meaningful part of the trajectory; there are many data mining methods to extract these locations. DBSCAN (density-based spatial clustering of applications with noise) is a classical density-based algorithm used to find the high-density areas in space, and different derivative methods of this algorithm have been proposed to find the stops in trajectories. However, most of these methods required a manually-set threshold, such as the speed threshold, for each feature variable. In our research, we first defined our new concept of move ability. Second, by introducing the theory of data fields and by taking our new concept of move ability into consideration, we constructed a new, comprehensive, hybrid feature-based, density measurement method which considers temporal and spatial properties. Finally, an improved DBSCAN algorithm was proposed using our new density measurement method. In the Experimental Section, the effectiveness and efficiency of our method is validated against real datasets. When comparing our algorithm with the classical density-based clustering algorithms, our experimental results show the efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

The NLSY97 data were used to explore the patterns of developmental trajectories of body weight in adolescence and how they affected the likelihood of college completion in young adulthood among 2,275 youths aged 13 and 14 in Wave 1. A strong weight trajectory gradient was found for rates of college completion. The study further explored the role of non-cognitive traits in the association between weight trajectories and college attainment. Non-cognitive traits were found to partially mediate the impact of certain weight trajectories on the likelihood of college completion. Some moderating effects of conscientiousness were also found. The findings from the gender and weight trajectory interaction terms showed that a stronger negative impact of weight trajectory on college completion is only observed for women in the late-teen-onset overweight group. This study highlights the importance of using a longitudinal weight measure and the role of non-cognitive traits in adolescent obesity research. [ABSTRACT FROM AUTHOR]

Rotation is one of the basic interaction tasks performed in 3D Virtual Environments (VEs). Chordball; a Rotation technique for touch-based, desktop and mouse-based 3D virtual environments was designed and evaluated. Index finger of a single hand was used for rotation about x, y and z axes. Interaction points, distance and direction of the finger"s movement was traced for rotation about an axis. Torque-effect and rotation speed with respect to finger"s move made the technique more realistic. The technique was implemented in Visual Stadio-10 using the OpenGl library and its performance was compared with other well-accepted rotation techniques. The technique was tested 288 times for rotation about different axes by twelve users. Statistical analysis revealed that the technique had better completion time with least loss of accuracy. It was concluded that the technique may improve rotation based interaction and can be used in a wide range of 3D virtual environments. [ABSTRACT FROM AUTHOR]

Prospective memory (PM) is the process associated with the task of realizing delayed intentions in the future. Researchers distinguish two types of PM, namely time-based PM (tbPM) and event-based PM (ebPM). Experiment 1 investigated the developmental trajectory of 3- to 5-year-old preschool children's PM ability, and the occurrence of delayed retrieval (children execute the PM task in a larger window of opportunity) in both tbPM and ebPM tasks. Results revealed that the 5-year-old children outperformed the 3- and 4-year-old children in PM. Moreover, delayed retrieval was more likely to occur in tbPM task than in ebPM task. In Experiment 2, the influence of ongoing task (OT) difficulty on PM performance was investigated with a sample of 5-year-old children. Results revealed no significant effect of OT difficulty on PM performance. In Experiment 3, we improved children's motivation level to complete the OT, then explored the influence of OT difficulty on children's PM performance. Results revealed that the effect of OT difficulty on PM performance became significant after increasing the children's motivation to complete the OT. These results provide insights into the mechanism of attentional resource allocation in PM tasks and have crucial educational and social implications. [ABSTRACT FROM AUTHOR]

Background: Depression and anxiety have been related to poorer self-reported physical functioning over time; however, objective measures of physical function are less frequently examined. This study assessed the 6-year trajectory of hand-grip strength and lung function in persons with depressive and/or anxiety disorders.Methods: At four waves (baseline, 2, 4, and 6 years) hand-grip strength and lung function were assessed in 2,480 participants, aged 18-65 years, of the Netherlands Study of Depression and Anxiety. Linear mixed models were used to examine the association between baseline psychiatric status (current and remitted depression and anxiety, healthy controls) and physical function during 6-year follow-up, adjusted for sociodemographics, lifestyle, and health indicators.Results: Although there were no differences in the rate of decline over time, women with current, but not remitted, depression and anxiety had poorer hand-grip strength (B = -1.34, P < .001) and poorer lung function (B = -11.91, P =.002) compared to healthy women during the entire 6-year follow-up. Associations with depression and anxiety severity measures confirmed dose-response relationships with objective physical function. In men, stronger 6-year decline of lung function was found in those with current disorders (current diagnosis-by-time: B = -11.72, P = .002) and even in those with remitted disorders (remitted diagnosis by time: B = -10.11, P = .04) compared to healthy men.Conclusions: Depression and anxiety are associated with consistently poorer hand-grip strength in women and poorer lung function in women and men over 6 years of time, implicating their long-lasting impact on physical functioning. [ABSTRACT FROM AUTHOR]

Background: This study assessed the association between timing and course of maternal depression from pregnancy onwards and children's cognitive development at ages 5 to 6. Potential interaction effects with child sex and family socioeconomic status were explored.Methods: One thousand thirty-nine mother-child pairs from the French EDEN mother-child birth cohort were followed from 24 to 28 weeks of pregnancy onwards. Based on Center for Epidemiological Studies Depression (CES-D) and Edinburgh Postnatal Depression Scale (EPDS) scores assessed at six timepoints, longitudinal maternal depressive symptom trajectories were calculated with a group-based semiparametric method. Children's cognitive function was assessed at ages 5 to 6 by trained interviewers with the Wechsler Preschool and Primary Scale of Intelligence Third Edition (WPPSI-III), resulting in three composite scores: Verbal IQ (VIQ), Performance IQ (PIQ), and Full-Scale IQ (FSIQ).Results: Five trajectories of maternal symptoms of depression could be distinguished: no symptoms, persistent intermediate-level depressive symptoms, persistent high depressive symptoms, high symptoms in pregnancy only, and high symptoms in the child's preschool period only. Multiple linear regression analyses showed that, compared to children of mothers who were never depressed, children of mothers with persistent high levels of depressive symptoms had reduced VIQ, PIQ, and FSIQ scores. This association was moderated by the child's sex, boys appearing especially vulnerable in case of persistent maternal depression.Conclusions: Chronicity of maternal depression predicts children's cognitive development at school entry age, particularly in boys. As maternal mental health is an early modifiable influence on child development, addressing the treatment needs of depressed mothers may help reduce the associated burden on the next generation. [ABSTRACT FROM AUTHOR]

Traffic volume estimation at the city scale is an important problem useful to many transportation operations and urban applications. This paper proposes a hybrid framework that integrates both state-of-art machine learning techniques and well-established traffic flow theory to estimate citywide traffic volume. In addition to typical urban context features extracted from multiple sources, we extract a special set of features from GPS trajectories based on the implications of traffic flow theory, which provide extra information on the speed-flow relationship. Using the network-wide speed information estimated from a travel speed estimation model, a volume related high level feature is first learned using an unsupervised graphical model. A volume re-interpretation model is then introduced to map the volume related high level feature to the predicted volume using a small amount of ground truth data for training. The framework is evaluated using a GPS trajectory dataset from 33,000 Beijing taxis and volume ground truth data obtained from 4,980 video clips. The results demonstrate effectiveness and potential of the proposed framework in citywide traffic volume estimation. [ABSTRACT FROM PUBLISHER]

The importance of archaeometric investigations, performed with technical support is not only that eases the work of archaeologists, but also contributes to optimize human, financial and time resources. Thus the study highlights the results of investigation of an archaeological site from the imperial roman era through a method specific to electrical engineering. Accordingly, based on some soil resistivity measurements made in the Legionary Camp of Potaissa - fortress where the 5th Macedonian Legion camped, members of the Archaeometry Laboratory from the Technical University of Cluj-Napoca were able to identify and establish the trajectory of buried walls that were marking the specific construction of the barracks belonging to the troops in Cohors I Miliaria. In order to perform this task, a genetic algorithm based technique was used to determine the different soil layers. [ABSTRACT FROM AUTHOR]

The movements that we make with our body vary continuously along multiple dimensions. However, many of the tools and techniques presently used for coding and analyzing hand gestures and other body movements yield categorical outcome variables. Focusing on categorical variables as the primary quantitative outcomes may mislead researchers or distort conclusions. Moreover, categorical systems may fail to capture the richness present in movement. Variations in body movement may be informative in multiple dimensions. For example, a single hand gesture has a unique size, height of production, trajectory, speed, and handshape. Slight variations in any of these features may alter how both the speaker and the listener are affected by gesture. In this paper, we describe a new method for measuring and visualizing the physical trajectory of movement using video. This method is generally accessible, requiring only video data and freely available computer software. This method allows researchers to examine features of hand gestures, body movement, and other motion, including size, height, curvature, and speed. We offer a detailed account of how to implement this approach, and we also offer some guidelines for situations where this approach may be fruitful in revealing how the body expresses information. Finally, we provide data from a small study on how speakers alter their hand gestures in response to different characteristics of a stimulus to demonstrate the utility of analyzing continuous dimensions of motion. By creating shared methods, we hope to facilitate communication between researchers from varying methodological traditions. [ABSTRACT FROM AUTHOR]

A path planning and tracking framework is presented to maintain a collision-free path for autonomous vehicles. For path-planning approaches, a 3-D virtual dangerous potential field is constructed as a superposition of trigonometric functions of the road and the exponential function of obstacles, which can generate a desired trajectory for collision avoidance when a vehicle collision with obstacles is likely to happen. Next, to track the planned trajectory for collision avoidance maneuvers, the path-tracking controller formulated the tracking task as a multiconstrained model predictive control (MMPC) problem and calculated the front steering angle to prevent the vehicle from colliding with a moving obstacle vehicle. Simulink and CarSim simulations are conducted in the case where moving obstacles exist. The simulation results show that the proposed path-planning approach is effective for many driving scenarios, and the MMPC-based path-tracking controller provides dynamic tracking performance and maintains good maneuverability. [ABSTRACT FROM PUBLISHER]

A trajectory-front for a surface magnetic field is formed by terminuses of trajectory-segments of given arc-radius which are emanating from a given point. In order to show how trajectories are spreaded we give estimates of their arc-lengths of trajectory-fronts. [ABSTRACT FROM AUTHOR]

With the advent of autonomous vehicles, in particular its adaptability to harsh conditions, the research and development of autonomous vehicles attract significant attention by not only academia but also practitioners. Due to the high risk, high cost, and difficulty to test autonomous vehicles under harsh conditions, the hardware-in-the-loop (HIL) scaled platform has been proposed as it is a safe, inexpensive, and effective test method. This platform system consists of scaled autonomous vehicle, scaled roadway, monitoring center, transmission device, positioning device, and computers. This paper uses a case of the development process of tracking control for high-speed U-turn to build the tracking control function. Further, a simplified vehicle dynamics model and a trajectory tracking algorithm have been considered to build the simulation test. The experiment results demonstrate the effectiveness of the HIL scaled platform. [ABSTRACT FROM AUTHOR]

The recent discovery of an enriched metallicity for the Smith high-velocity H I Cloud (SC) lends support to a Galactic origin for this system. We use a dynamical model of the galactic fountain to reproduce the observed properties of the SC. In our model, fountain clouds are ejected from the region of the disc spiral arms and move through the halo interacting with a pre-existing hot corona. We find that a simple model where cold gas outflows vertically from the Perseus spiral arm reproduces the kinematics and the distance of the SC, but is in disagreement with the cloud's cometary morphology, if this is produced by ram-pressure stripping by the ambient gas. To explain the cloud morphology, we explore two scenarios: (i) the outflow is inclined with respect to the vertical direction and (ii) the cloud is entrained by a fast wind that escapes an underlying superbubble. Solutions in agreement with all observational constraints can be found for both cases, the former requires outflow angles >40° while the latter requires ... 1000 km s-1 winds. All scenarios predict that the SC is in the ascending phase of its trajectory and has large -- but not implausible -- energy requirements. [ABSTRACT FROM AUTHOR]