Entire Trajectory Research Articles

A turning point-based offline map matching algorithm for urban road networks

Offline map matching is a crucial step to facilitate many trajectory-based services in urban areas by finding vehicles’ travel paths from recorded and stored trajectory data. This paper proposes a novel turning point-based offline map matching algorithm, which introduces the concept of vehicle turning points to implement map matching piecewisely. The algorithm first separates the entire trajectory into multiple sub-trajectories using the identified turning points. It then selects the best-matched path for each sub-trajectory from the corresponding K-shortest paths. Extensive experiments are conducted to compare the performance of our algorithm with five state-of-the-art map matching algorithms in terms of four different criteria, including one correctly matched criterion, two incorrectly matched criteria, and one computation time-related criterion. Experimental results show that our algorithm has the best average matching accuracy and efficiency at different sampling intervals. Specifically, compared with the five benchmark algorithms, our algorithm can improve the correctly matched percentages by 1.43% to 34.66%, reduce the incorrectly matched percentages by 15.23% to 56.79%, and improve the matching speeds by 3.16–61.01 times.

Evolutionary development of the Homo antecessor scapulae (Gran Dolina site, Atapuerca) suggests a modern-like development for Lower Pleistocene Homo

Two well-preserved, subadult 800 ky scapulae from Gran Dolina belonging to Homo antecessor, provide a unique opportunity to investigate the ontogeny of shoulder morphology in Lower Pleistocene humans. We compared the H. antecessor scapulae with a sample of 98 P. troglodytes and 108 H. sapiens representatives covering seven growth stages, as well as with the DIK-1-1 (Dikika; Australopithecus afarensis), KNM-WT 15000 (Nariokotome; H. ergaster), and MH2 (Malapa; A. sediba) specimens. We quantified 15 landmarks on each scapula and performed geometric morphometric analyses. H. sapiens scapulae are mediolaterally broader with laterally oriented glenoid fossae relative to Pan and Dikika shoulder blades. Accordingly, H. antecessor scapulae shared more morphological affinities with modern humans, KNM-WT 15000, and even MH2. Both H. antecessor and modern Homo showed significantly more positive scapular growth trajectories than Pan (slopes: P. troglodytes = 0.0012; H. sapiens = 0.0018; H. antecessor = 0.0020). Similarities in ontogenetic trajectories between the H. antecessor and modern human data suggest that Lower Pleistocene hominin scapular development was already modern human-like. At the same time, several morphological features distinguish H. antecessor scapulae from modern humans along the entire trajectory. Future studies should include additional Australopithecus specimens for further comparative assessment of scapular growth trends.

Leveraging Deep Learning for Visual Odometry Using Optical Flow.

In this paper, we study deep learning approaches for monocular visual odometry (VO). Deep learning solutions have shown to be effective in VO applications, replacing the need for highly engineered steps, such as feature extraction and outlier rejection in a traditional pipeline. We propose a new architecture combining ego-motion estimation and sequence-based learning using deep neural networks. We estimate camera motion from optical flow using Convolutional Neural Networks (CNNs) and model the motion dynamics using Recurrent Neural Networks (RNNs). The network outputs the relative 6-DOF camera poses for a sequence, and implicitly learns the absolute scale without the need for camera intrinsics. The entire trajectory is then integrated without any post-calibration. We evaluate the proposed method on the KITTI dataset and compare it with traditional and other deep learning approaches in the literature.

Dynamics of the movement of the descent vehicle in the atmosphere of Mars with the use of inflatable brakes in the lower atmosphere

Currently, more and more spacecrafts are being designed, to explore the planets of the solar system. One of the very important stages in the execution of such missions is the movement from the moment of deorbiting until the moment of approaching the surface. The entire descent trajectory from the moment of separation to contact with the surface is a very important stage and a very important object of research particularly in the field of Computational Fluid Dynamics (CFD). It is to this process that a series of articles by the authors is devoted. This article is devoted to the movement of the descent vehicle in the lower atmosphere. Some parameters of the descent vehicle movement at this stage of movement are analyzed. The importance of such research and the possibility of using inflatable braking devices are shown.

The Effects of Weather on Avian Growth and Implications for Adaptation to Climate Change

Climate change is forecasted to generate a range of evolutionary changes and plastic responses. One important aspect of avian responses to climate change is how weather conditions may change nestling growth and development. Early life growth is sensitive to environmental effects and can potentially have long-lasting effects on adult phenotypes and fitness. A detailed understanding of both how and when weather conditions affect the entire growth trajectory of a nestling may help predict population changes in phenotypes and demography under climate change. This review covers three main topics on the impacts of weather variation (air temperature, rainfall, wind speed, solar radiation) on nestling growth. Firstly, we highlight why understanding the effects of weather on nestling growth might be important in understanding adaptation to, and population persistence in, environments altered by climate change. Secondly, we review the documented effects of weather variation on nestling growth curves. We investigate both altricial and precocial species, but we find a limited number of studies on precocial species in the wild. Increasing temperatures and rainfall have mixed effects on nestling growth, while increasing windspeeds tend to have negative impacts on the growth rate of open cup nesting species. Thirdly, we discuss how weather variation might affect the evolution of nestling growth traits and suggest that more estimates of the inheritance of and selection acting on growth traits in natural settings are needed to make evolutionary predictions. We suggest that predictions will be improved by considering concurrently changing selection pressures like urbanization. The importance of adaptive plastic or evolutionary changes in growth may depend on where a species or population is located geographically and the species’ life-history. Detailed characterization of the effects of weather on growth patterns will help answer whether variation in avian growth frequently plays a role in adaption to climate change.

Robot Localisation Using UHF-RFID Tags: A Kalman Smoother Approach †.

Autonomous vehicles enable the development of smart warehouses and smart factories with an increased visibility, flexibility and efficiency. Thus, effective and affordable localisation methods for indoor vehicles are attracting interest to implement real-time applications. This paper presents an Extended Kalman Smoother design to both localise a mobile agent and reconstruct its entire trajectory through a sensor-fusion employing the UHF-RFID passive technology. Extensive simulations are carried out by considering the smoother optimal-window length and the effect of missing measurements from reference tags. Monte Carlo simulations are conducted for different vehicle trajectories and for different linear and angular velocities to evaluate the method accuracy. Then, an experimental analysis with a unicycle wheeled robot is performed in real indoor scenario, showing a position and orientation root mean square errors of 15 cm, and 0.2 rad, respectively.

Multiphase Trajectory Optimization of a Lunar Return Mission to an LEO Space Station

Lunar exploration architecture can be made more flexible and reliable with the support of a low-Earth orbit (LEO) space station. This study therefore evaluated a proposed hybrid optimization scheme to design the entire trajectory of a reusable spacecraft starting from trans-Earth injection (EI) at the perilune and ending at an LEO space station. As such a trajectory has multiple constraints and multiple dynamical models, it is divided into the trans-Earth phase, aerocapture phase, and postatmospheric phase. The optimization scheme is performed at two levels: sublevel and top level. At the sublevel, two novel pseudo rules are proposed to optimize the trans-Earth trajectory so that it satisfies the coplanar constraints of the space station. Then, in the aerocapture phase, the bank angle is optimized to satisfy the mission constraints, and in the atmospheric phase, the one-impulsive maneuver is performed and optimized to insert the spacecraft into the target space station orbit. The multiple phases are connected to each other by boundary conditions where the terminal state of the previous phase is transformed into the initial state of the following phase. At the top level, the vacuum perigee height is selected as the mission design variable based on problem characteristics analysis and a hybrid optimization scheme is conducted to minimize the total velocity increment. The simulation results demonstrate that the proposed hybrid optimization method is effective for the design of an entire trajectory with acceptable velocity cost which is less than that in the previous study. The coplanar constraints of the space station and other mission constraints in each phase are also satisfied. Furthermore, the proposed trajectory design method is shown to be applicable to a reusable spacecraft returning to an LEO space station parked in any arbitrary orbital plane.

Повышение безопасности и эксплуатационной эффективности контейнерных перевозок

Introduction. Currently, there is a logistic problem in container transportation technology related to the transportation of empty freight containers, as returnable containers, since an empty container takes up as much space as a full one. A promising direction for solving this problem is the introduction of folding cargo containers. A disadvantage of this approach is the likelihood of injury to the maintenance personnel, which must be inside in the process of folding and unfolding. Problem Statement. The objective of this study is to study the conditions for increasing the safety of preparatory work due to the design of the container, the main feature of which is the ability to realize the effect of functional self-adaptation to working conditions. Theoretical Part. This approach allows us, when folding and unfolding, to balance the changing reactions from the own masses and the moments of its moving body parts by means of the corresponding lockable gas springs. Gas springs connect leading links and driven kinematic chains thereby ensuring that their movement in a given speed mode on the entire trajectory is independent of the speed of the driving link. For the practical implementation of the proposed design solution, the paper presents a general method for the synthesis of an adaptive controller of the container mechanisms in the process of folding and unfolding its moving parts. Conclusion. Testing of the container showed that the effect of functional self-adaptability is quite well implemented along the entire trajectory of the container elements without the use of external lifting mechanisms.

Integrating psycho-oncology services in cancer care in India.

Psychological distress is often an under-diagnosed problem in cancer care. Addressing psychosocial issues would enhance treatment compliance, physician-patient relationship, treatment efficacy and quality of life. This article emphasizes the importance of integrating psycho-oncology services in cancer care and attempts to define the various roles that a psycho-oncologist can play across the entire trajectory. It also highlights the indispensable role played by the oncologists' referrals in maximizing the benefits of psycho-oncology services received by patients and their caregivers.

IFTS: A Location Privacy Protection Method Based on Initial and Final Trajectory Segments

Privacy protection problem is one of the most concerning issues related to Location-Based Services (LBS) in our daily life. Privacy protection of LBS often requires anonymizing customer's trajectory data. Currently available methods for trajectory anonymity often assume an entire trajectory as one anonymous unit, which may lead to low anonymity efficiency due to the massive amount of trajectory data, especially for customers travel through a long road. Considering people's routine activities, the starting and ending locations of a trip often uncover the user's request intent, which may lead to exposure of user privacy. In order to address the problem of inefficient trajectory anonymity, we propose a location privacy protection method that is based on the initial and final trajectory segmentation (IFTS) in this paper. In the IFTS method, the road network structure is first transformed into an edge cluster model based on its location type. Then, the user trajectory is divided to segments according to the temporal sequence of the ingress and egress nodes. The initial and final trajectory segments are identified and divided into equivalence classes, which then are used for constructing a trajectory graph and the corresponding k-anonymous set. Our experimental results show that the proposed method can reduce the anonymous area, improve anonymity efficiency, and enhance trajectory data utilization compared to the existing methods for trajectory anonymity.

Extracellular vesicle-shuttled miRNAs: a critical appraisal of their potential as nano-diagnostics and nano-therapeutics in type 2 diabetes mellitus and its cardiovascular complications.

Type 2 diabetes mellitus (T2DM) is a complex multifactorial disease causing the development of a large range of cardiovascular (CV) complications. Lifestyle changes and pharmacological therapies only partially halt T2DM progression, and existing drugs are unable to completely suppress the increased CV risk of T2DM patients. Extracellular vesicles (EV)s are membrane-coated nanoparticles released by virtually all living cells and are emerging as novel mediators of T2DM and its CV complications. As a matter of fact, several preclinical models suggest a key involvement of EVs in the initiation and/or progression of insulin resistance, β-cell dysfunction, diabetic dyslipidaemia, atherosclerosis, and other T2DM complications. In addition, preliminary findings also suggest that EV-associated molecular cargo, and in particular the miRNA repertoire, may provide with useful diagnostic and/or prognostic information for the management of T2DM. Here, we review the latest findings showing that EV biology is altered during the entire trajectory of T2DM, i.e. from diagnosis to development of CV complications. We also critically highlight the potential of this emerging research field, by describing both preclinical and clinical observations, and the limitations that must be overcome to translate the preclinical findings into the development of EV-based nano-diagnostic and/or nano-therapeutic tools. Finally, we summarize how two lifestyle changes known to prevent or limit T2DM, i.e. diet and exercise, affect EV number and composition, with a focus on the possible role of EVs contained in food in shaping metabolic responses, a promising approach still in its infancy.

Developments in National Cancer Control Programmes in Europe - Results From the Analysis of a Pan-European Survey.

IntroductionNational Cancer Control Programmes (NCCPs) provide a country’s policy framework for the development of cancer control, focussing on the reduction of cancer morbidity and mortality and improving quality of life of cancer patients.ObjectiveExploring and analysing to which extent some of the key elements of the European Guide for Quality National Cancer Control Programmes (Guide) are implemented in NCCPs in the EU.MethodsSurvey carried out through 30 countries, EU members, Iceland, Montenegro, Norway and Turkey, focussing on stakeholders’ participation, inclusion of all the envisaged chapters from the Guide as well as implementation and dissemination.ResultsThe results of the policy survey on European NCCPs carried out within Cancer Control Joint Action (CANCON JA) are presented. The response was 30 out of 35 countries. In total, 28 out of 30 countries, which completed the survey, had an NCCP or another cancer document. Cancer documents were mostly single documents, managed and supervised by the respective Ministries of Health and communicated to the public via websites and press. Nine documents were defined as programmes, eight as plans and six as strategies; in five countries, terminology was mixed. Regarding the content, recommended by the Guide from 2015, comprising ten chapter areas in three parts. Only 10 countries included in their NCCPs all elements suggested in the Guide.ConclusionBased on our results, we can see that a more comprehensive approach in the process of NCCPs is needed. Policy should focus on the development of instruments for efficient cancer management, which would encompass the entire trajectory of the cancer care from diagnosis to survivorship and supportive care.

Plasticity of Epididymal Adipose Tissue in Response to Diet-Induced Obesity at Single-Nucleus Resolution

Adipose tissues display a remarkable ability to adapt to the dietary status. Here, we have applied single-nucleus RNA-seq to map the plasticity of mouse epididymal white adipose tissue at single-nucleus resolution in response to high-fat-diet-induced obesity. The single-nucleus approach allowed us to recover all major cell types and to reveal distinct transcriptional stages along the entire adipogenic trajectory from preadipocyte commitment to mature adipocytes. We demonstrate the existence of different adipocyte subpopulations and show that obesity leads to disappearance of the lipogenic subpopulation and increased abundance of the stressed lipid-scavenging subpopulation. Moreover, obesity is associated with major changes in the abundance and gene expression of other cell populations, including a dramatic increase in lipid-handling genes in macrophages at the expense of macrophage-specific genes. The data provide a powerful resource for future hypothesis-driven investigations of the mechanisms of adipocyte differentiation and adipose tissue plasticity.

Simplified Modelling of Inclined Turbulent Dense Jets

An analytical approximation to the entire centerline trajectory of inclined round dense jets in dimensionless form is proposed, in terms of a fourth degree polynomial. The coefficients of the polynomial for a certain inclination angle can be easily obtained if the position of the maximum height and the return point are known. Experimental data of the authors are used to determine these coefficients for six inclination angles between 35° and 75°. The resulting trajectories are then compared to data of other investigators and found to be in good agreement. The variation of the polynomial coefficients with inclination angle is also studied. The proposed analytical expression allows for a straightforward computation of the trajectory length for any inclination angle in the range studied. It is found that the longest trajectory occurs for the 60° angle. The relation between the computed length and the measured minimum (centerline) dilutions at the location of maximum height and at the return point is examined. Finally, the laws governing the variation of the minimum dilution with the axial distance from the source are explored and similarities with the laws of simple jets and plumes are discussed.

Exploration of Statewide Fragmentation of Activity and Travel and a Taxonomy of Daily Time Use Patterns using Sequence Analysis in California

Sequence analysis is used in this paper to measure fragmentation in activity participation and travel. Fragmentation here is defined as the sequencing of many short and long activities and trips that happen in a personal daily schedule. Studying sequences of daily episodes (each activity at a place and each trip) is preferable over other techniques of studying activity–travel behavior because sequences include the entire trajectory of a person’s activity during a day while jointly considering the number of activities and trips, their ordering, and their durations. We first identify places visited and duration at each place on a minute-by-minute basis, then we derive representative daily behavior patterns using hierarchical clustering. Our study shows there are at least nine distinct daily patterns with different sequencing of activities and travel as well as travel time ratios and modal split. These patterns include typical commute to work or school, staying at home all day, or traveling extensively. As expected, day of the week plays a major role in the type of daily activity–travel patterns. Travel time ratios are also examined for each daily pattern and we find differences in the role played within each pattern between central city, suburban, exurban, and rural dwellers. In a comparison of couples, we find systematically higher fragmentation in households that have children and their parents are employed, with women showing higher fragmentation in the activity–travel patterns.

The future of health professions education: Emerging trends in the United States.

The future of health professions education: Emerging trends in the United States.

Trajectory Planning Based on Spatio-Temporal Map With Collision Avoidance Guaranteed by Safety Strip

Trajectory planning for the unmanned vehicle in the complex environment has always been a challenging task. Planned trajectory with the corresponding target velocity or acceleration sequence must be collision-free guaranteed and as comfortable as possible on the premise of obeying the traffic rules and interaction with other dynamic social vehicles. To meet this requirement, this paper proposes a framework for trajectory planning based on spatio-temporal map. Due to the time layer architecture in the map, the trajectory can be generated with velocity and acceleration simultaneously, and the whole trajectory is constrained within a `safety strip', resulting in an efficient and safety guaranteed trajectory. The framework is composed of three sections: rough search, fine optimization and safety strip-based collision avoidance. For rough search, we propose an improved A* algorithm implemented in the discrete time layer to find out the suboptimal states efficiently. In fine optimization, the B-spline curve is exploited to connect the searched states into a continuous trajectory. And the optimal control points of B-spline are further grouped into several segments, forming the safety strip which is actually the distribution space of the planned trajectory. If necessary, an adjustment will be applied to keep the strip away from the collision zone, making the entire trajectory completely collision-free. Experiments on both public dataset and self-driving simulator show that the proposed framework can adapt to different kinds of complex traffic scenes well.

Stability of an Elastically Supported Cylinder in a Circular Viscous Fluid Flow

A system consisting of two cylinders (the inner cylinder is elastically supported and the outer cylinder is rigidly fixed) and a circulation flow of viscous incompressible fluid between them is considered. In the equilibrium position the cylinders are coaxial and the inner one rotates at a constant angular velocity Ω. An expression is obtained of the force acting on the inner cylinder from the side of the fluid in the approximation of large Reynolds numbers at a small deviation of the inner cylinder from its equilibrium position. It is shown that the force has a hereditary character and depends on the entire trajectory of motion. The stability of the position of the inner elastically supported cylinder is studied in the linear approximation taking into account the hereditary force acting on the inner cylinder.

REAL-TIME SLAM FOR THE OFF-ROAD AUTONOMOUS DRIVING

Abstract. In this paper we propose a new SLAM algorithm that is robust to the changing environment of the countryside. The hardware part consists of two separate machine vision cameras, joined in stereo, and can be supplemented with LiDAR, IMU and GPS. We introduce a method that can be used to reliably calculate the position of a vehicle in natural environments. To estimate the pose and produce a three-dimensional reconstruction we use a stereo camera rig, inertial measurement unit and the global positioning system. While solving the problem of visual odometry in outdoor scenes we faced a number of difficulties, arising from high dynamic range, as well as the presence of a large number of "similar elements", such as leaves, grass, trees and etc. Under these conditions, it becomes difficult to match feature points in image sequences. HOG-based methods, such as SIFT, SURF and others often do not obtain good matching due to noise, lack of a sufficient number of gradients, and the presence of identical domains. Using neighborhood-based detectors such as DAISY often allows to identify the correct matches, but using them is worth it too expensive. These methods are very demanding on the computational resources and prone to drift. We needed a method that is less expensive, but at the same time provides sufficient accuracy in the trajectory estimation. Direct methods, such as optical flow calculating or direct image matching allow us to map point-to-point in these conditions with high reliability. They also have disadvantages that can be eliminated by using an IMU and modern algorithms. To improve the quality of the algorithms, we solve the reconstruction problem for several frames using the Levenberg-Marquardt optimization method for bundle adjustment. Each pass optimizes frames that are directly related to the last one, we use two threads that perform partial and full optimization of the entire trajectory using graphs to significantly increase the performance of the method.

Map matching based on multi-layer road index

This study develops a new map matching algorithm targeting off-line applications. The algorithm takes a holistic view of the entire GPS trajectory and finds its match by first dividing it into several segments. This segmentation is made possible through creating a multi-layer road index system for the original road network. For each segment, a global map matching strategy is employed to identify the best match. The algorithm is compared against three state-of-the-art map matching algorithms from the literature. To get ground truth data, we design and perform numerous test drives with predefined paths that have a total length of 234 km. GPS trajectories recorded during the test drives are used to evaluate the algorithms. Our numerical experiments show the proposed algorithm improves match efficiency by up to two order of magnitude compared to the benchmark algorithms. Importantly, it achieves this remarkable speedup with negligible losses in matching accuracy.