Trajectory Theory Research Articles

Optimization and Control Strategies for Mechanical Vehicle Trajectory Research

With the rapid advancement of contemporary transportation and automation technology, the optimization of mechanical vehicle trajectories and control strategies have gradually become a focal area of research. Precise trajectory optimization not only enhances the driving efficiency of vehicles but also significantly reduces energy consumption and safety hazards. This paper reviews the basic theory of mechanical vehicle motion trajectories, focusing on the methods of trajectory optimization and control strategies. It covers model-based trajectory optimization, data-driven optimization methods, and various control strategies. Through an analysis of existing research, it points out the challenges and prospects of applying trajectory optimization and control strategies in complex environments.

Enhancing cathode design by considering complex motion and variations of electric field distribution in counter-rotating electrochemical machining

The counter-rotating electrochemical machining (CRECM) shows unique potential in the machining of thin-walled rotating parts with complex convex structures. CREM realizes the shaping of complex convex structures through the relative rotation of the cathode and anode. The complex motion pattern and electric field distribution make it difficult to apply the existing cathode design methods to CRECM. To solve this problem, the matrix equations of cathode motion based on the kinematics and the electric field simulation model are established. The motion trajectories and edge contours at different angles are analyzed. The rotational overlap theory of motion trajectories under the windows at different angles is proved. Besides, the relationship between electric field distribution and the convex structure forming under different angle windows is studied, and the fundamental reason for deviations occurs when the convex profile is rotated to coincide is revealed. Therefore, a prediction model of the sidewall dissolution is established to correct this deviation, thereby deriving a high-precision design formula for the cathode windows of the high convex structures. By designing a cathode with oval-like windows to curry out CRECM experiments, the array-arranged (30 × 5) circular high convex structure with a maximum roundness error of 0.065 mm is successfully fabricated.

Bilingualism and second-order theory of mind development in autistic children over time: Longitudinal relations with language, executive functions, and intelligence.

Theory of Mind has long been studied as a core weakness in autism spectrum disorder due to its relationship with social reciprocity, while bilingualism has been shown to compensate for autistic individuals' mentalizing weaknesses. However, our knowledge of the Theory of Mind developmental trajectories of bilingual and monolingual autistic children, as well as of the factors related to Theory of Mind development in autism spectrum disorder is still limited. The current study has examined first- and second-order Theory of Mind skills in 21 monolingual and 21 bilingual autistic children longitudinally across three time points, specifically at ages 6, 9, and 12, and also investigated associations between Theory of Mind trajectories and trajectories of the children's language, intelligence and executive function skills. The results reveal that bilingual autistic children outperformed their monolingual peers in second-order Theory of Mind at ages 9 and 12, and that intelligence and, especially, expressive vocabulary skills played a pivotal role in advancing bilingual autistic children's second-order Theory of Mind development. On the other hand, monolingual autistic children only managed to capitalize on their language and intelligence resources at age 12. The findings highlight the importance of investigating bilingualism effects on autistic children's advanced cognitive abilities longitudinally.

Determining the coordinates of unmanned aerial vehicles

The purpose of the work was to develop a method for determining unmanned aerial vehicles’ (UAVs) coordinates, trajectory and parameters of their spatial movements by means of kinematic projection. The paper analyses the use of technologies for determining coordinates and spatial movements of aircraft trajectories. The principle of the kinematic scheme of fixing moving objects by means of orthogonal and kinematic design has been developed. The principle scheme of determining UAV coordinates by kinematic projection was studied. The theoretical mathematical dependencies of the determination and calculations of the coordinates of spatial movements of unmanned aerial vehicles have been practically verified. The main object of research in this work was the theory of kinematic design as a means of graphically displaying the patterns of spatial movements of objects. The subject of the study was the specific features of searching and recording the trajectories of spatial movements of unmanned aerial vehicles in order to determine the coordinates of their instantaneous location in space. In the process of conducting theoretical and experimental research, methods and techniques of physical and mathematical modelling of fast-moving processes and mathematical statistics of analysis and classification of their results were used. The basis of the experimental study was the theory of mapping coordinates and trajectories of spatial movements of moving objects by means of graphic geometry when combining classical orthogonal design with dynamic features of kinematic design. For an objective assessment of the results of the theoretical and experimental study of the dynamics of objects moving in space, the classical theory of research planning with a mathematical apparatus for processing their results was used. Graphical models of UAV coordinate fixation were made with the use of computer technology and the AutoCAD graphic editor software.

Conditional Dynamics in Heterodyne Detection of Superradiant Lasing with Incoherently Pumped Atoms.

In this Letter, we use quantum trajectory theory to simulate heterodyne detection of narrow bandwidth superradiant lasing from an incoherently excited atomic ensemble. To this end, we describe the system dynamics and account for stochastic measurement backaction by second-order mean-field theory. Our simulations show how heterodyne measurements break the phase symmetry, and initiate the atomic coherence with a random phase and a long temporal phase coherence. More importantly, our theory allows direct simulation of experimental procedures for extraction of spectral information which do not lend themselves to evaluation with the quantum regression theorem.

Quantum-fluctuation asymmetry in multiphoton Jaynes–Cummings resonances

We explore the statistical behavior of the light emanating from a coherently driven Jaynes–Cummings (JC) oscillator operating in the regime of multiphoton blockade with two monitored output channels causing the loss of coherence at equal rates. We do so by adopting an operational approach that draws the particle and wave aspects of the forward-scattered radiation together, building upon the relationship between quantum optical correlation functions and conditional measurements. We first derive an analytical expression of the intensity cross-correlation function at the peak of the two-photon JC resonance to demonstrate the breakdown of detailed balance. The application of the quantum trajectory theory in parallel with the quantum regression formula subsequently uncovers various aspects of temporal asymmetry in the quantum fluctuations characterizing the cascaded process through which a multiphoton resonance is established and read out. We find that monitoring different quadratures of the cavity field in conditional homodyne detection affects the times waited between successive photon counter “clicks,” which in turn trigger the sampling of the homodyne current. Despite the fact that the steady-state cavity occupation is of the order of a photon, monitoring of the developing bimodality also impacts the ratio between the emissions directed along the two decoherence channels.

Postpartum recovery after severe maternal morbidity in Kilifi, Kenya: a grounded theory of recovery trajectories beyond 42 days

IntroductionThe burden of severe maternal morbidity is highest in sub-Saharan Africa, and its relative contribution to maternal (ill) health may increase as maternal mortality continues to fall. Women’s perspective of...

Examining the communication work of women whohave tested BRCA-positive: "I feel this responsibility to letpeopleknow".

Inheriting a pathogenic variant in the BRCA1 or BRCA2 gene considerably increases a woman's risk levels for developing breast and ovarian cancer. In addition to serious physical health implications, women with a BRCA pathogenic variant may face psychosocial challenges, including those related to navigating the often demanding process of communicating about topics regarding BRCA with family and other social network members. Based on in-depth interviews with 24 women who tested BRCA-positive, we found that-consistent with the conceptualization of communication work articulated by Donovan-Kicken etal. (2012) as an extension of the theory of illness trajectories (Corbin & Strauss, 1988)-the labor of communicating about BRCA genetic risk entails (a) duties, (b) challenges, (c) strategies, and (d) shared work. Within each category, our results illuminate particular characteristics of communication work for women who have tested BRCA-positive, which are commonly tied to the profound health consequences that a pathogenic variant may have for them and, potentially, for their genetic relatives. Our findings offer useful theoretical implications regarding communication work in this context. Furthermore, our results yield valuable practical insight for genetic counselors and other health care professionals regarding the struggles that can accompany communication work for women who have tested BRCA-positive as well as the strategies that participants reported using to manage or avoid these challenges.

Proposal for a Hypothetical Learning Path Using GeoGebra in Learning Numerical Sequences

A hypothetical learning path is proposed for the teaching-learning of numerical sequences in second grade secondary school students, it is theoretically based in a Duval’s Theory of Semiotic Representation Registers and methodologically based on GeoGebra & Hypothetical Learning Path. It is intended to contribute to this field of mathematics given that there are not many the works in this regard, a fact that motivates the facilitation of better perspectives for students in learning the mathematical object numerical sequences. According to the hypothetical learning trajectory theory, each stage of learning requires a series of preconditions and appropriate instructional approaches so that the individual can progress. These stages include: 1) Acquisition of basic knowledge 2) Application of skills 3) Automation 4) Integration. It is concluded that it must be applied in the classroom to know the effectiveness of this trajectory.

Why is hospital discharge so difficult? Reconsidering patient trajectories in theory and practice: Insights from an ethnographic study of transitions in hip fracture care

This paper combines translational mobilisation theory and assemblage thinking to elaborate the patient trajectory concept. Deploying ethnographic research on transitions in hip fracture care in Wales (2014–2016), it describes and explains the structures and logics that condition transition interfaces, how transition infrastructures enact patients and with what effects. Comparative analysis of transition in three distinctive assemblages offers new insights into the challenges of hospital discharge and opportunities for research and improvement.

Lie Algebraic Quantum Phase Reduction.

We introduce a general framework of phase reduction theory for quantum nonlinear oscillators. By employing the quantum trajectory theory, we define the limit-cycle trajectory and the phase according to a stochastic Schrödinger equation. Because a perturbation is represented by unitary transformation in quantum dynamics, we calculate phase response curves with respect to generators of a Lie algebra. Our method shows that the continuous measurement yields phase clusters and alters the phase response curves. The observable clusters capture the phase dynamics of individual quantum oscillators, unlike indirect indicators obtained from density operators. Furthermore, our method can be applied to finite-level systems that lack classical counterparts.

Reduction of cone-beam CT artifacts in a robotic CBCT device using saddle trajectories with integrated infrared tracking.

Cone beam computed tomography (CBCT) is widely used in many medical fields. However, conventional CBCT circular scans suffer from cone beam (CB) artifacts that limit the quality and reliability of the reconstructed images due to incomplete data. Saddle trajectories in theory might be able to improve the CBCT image quality by providing a larger region with complete data. Therefore, we investigated the feasibility and performance of saddle trajectory CBCT scans and compared them to circular trajectoryscans. We performed circular and saddle trajectory scans using a novel robotic CBCT scanner (Mobile ImagingRing (IRm); medPhoton, Salzburg, Austria). For the saddle trajectory, the gantry executed yaw motion up to using motorized wheels driving on the floor. An infrared (IR) tracking device with reflective markers was used for online geometric calibration correction (mainly floor unevenness). All images were reconstructed using penalized least-squares minimization with the conjugate gradient algorithm from RTK with voxel size. A disk phantom and an Alderson phantom were scanned to assess the image quality. Results were correlated with the local incompleteness value represented by , which was calculated at each voxel as a function of the source trajectory and the voxel's 3D coordinates. We assessed the magnitude of CB artifacts using the full width half maximum (FWHM) of each disk profile in the axial center of the reconstructed images. Spatial resolution was also quantified by the modulation transfer function at 10% (MTF10). When using the saddle trajectory, the region without CB artifacts was increased from 43 to 190mm in the SI direction compared to the circular trajectory. This region coincided with low values for . When was larger than 0.02, we found there was a linear relationship between the FWHM and . For the saddle, IR tracking allowed the increase of MTF10 from 0.37 to 0.98 lp/mm. We achieved saddle trajectory CBCT scans with a novel CBCT system combined with IR tracking. The results show that the saddle trajectory provides a larger region with reliable reconstruction compared to the circular trajectory. The proposed method can be used to evaluate other non-circulartrajectories.

Well blowout Flame's thermal radiation prediction under environmental wind based on multi-point heat sources and inverse analysis

This study addresses the inadequacy of traditional multi-point source thermal radiation models in predicting the thermal radiation of gas well blowout fires under windy conditions. Initially, a Computational Fluid Dynamics (CFD) approach for predicting thermal radiation from well blowout jet flames was developed and validated against existing literature. Subsequently, the impact of wind on the thermal radiation of well blowout flames was thoroughly analyzed based on CFD model. Next, a novel predictive model for the center trajectory of well blowout flames under wind conditions was introduced based on CFD numerical simulation results and non-reactive jet trajectory theory. Building upon this, a novel prediction method of well blowout flame's thermal radiation under wind condition was proposed based on weighted multi-point sources model. Finally, the weights within proposed model were refined using an inverse optimization technique, specifically the Conjugate Gradient Global Optimization Algorithm, while also establishing a correlation between the optimal weight and the operating condition parameters of well blowout fires. Results indicated that the average difference between the thermal radiation values computed by the proposed method and those derived from numerical simulations was less than 10%. And the proposed model demonstrates clear superiority, particularly in terms of accuracy and convenience compared with traditional multi-point source model and single point source model. This research offers a practical and effective method for predicting thermal radiation from well blowout flames under wind conditions, which was of great significance for well blowout fire's disposal and rescue.

A quantum trajectory picture of single photon absorption and energy transport in photosystem II.

We use quantum trajectory theory to study the dynamics of the first step in photosynthesis for a single photon interacting with photosystem II (PSII). By considering individual trajectories we are able to look beyond the ensemble average dynamics to compute the PSII system evolution conditioned upon individual photon counting measurements. Measurements of the transmitted photon beam strongly affects the system state, since detection of an outgoing photon confirms that the PSII must be in the electronic ground state, while a null measurement implies it is in an excited electronic state. We show that under ideal conditions, observing the null result transforms a state with a low excited state population to a state with nearly all population contained in the excited states. We study the PSII dynamics conditioned on such photon counting for both a pure excitonic model of PSII and a more realistic model with exciton-phonon coupling to a dissipative phononic environment. In the absence of such coupling, we show that the measured fluorescence rates show oscillations constituting a photon-counting witness of excitonic coherence. Excitonic coupling to the phonon environment has a strong effect on the observed rates of fluorescence, damping the oscillations. Addition of non-radiative decay and incoherent transitions to radical pair states in the reaction center to the phononic model allows extraction of a quantum efficiency of 92.5% from the long-time evolution, consistent with bulk experimental measurements.

Living with Parkinson’s in England during and beyond COVID-19 restrictions: a longitudinal qualitative study

Objectives Government-enforced lockdown restrictions associated with preventing the spread of the COVID-19 virus had a series of unintended, negative effects. One group of individuals whose physical and mental health was significantly and disproportionately impacted were those with Parkinson’s. However, research has been mainly cross-sectional, with no previous study qualitatively following up participants through both lockdowns and the easing of restrictions. Consequently, this study aimed to provide a detailed understanding of the experience of lockdowns and the easing of restrictions on the physical and mental health of people with Parkinson’s. Method Data from semi-structured interviews collected at four time points across an 18-month period (May 2020 – September 2021) from the same participants (six men and four women) were analysed using interpretative phenomenological analysis. Results Three themes were derived: (1) Wrestling with a Parkinson’s identity, agency and control during the pandemic; (2) The encroachment and acceleration of a Parkinson’s future; and (3) Recalibrating priorities from COVID-19 to Parkinson’s. Conclusion As currently the only published study to provide an in-depth longitudinal analysis with this population, we used a more dynamic theoretical account, Strauss and Corbin’s theory of illness trajectories, to understand the findings and suggest ways of supporting individuals with Parkinson’s in this stage of the pandemic. The scale and breadth of the support needed is a significant challenge for current statutory systems.

An orthotropic continuum model with substructure evolution for describing bone remodeling: an interpretation of the primary mechanism behind Wolff's law.

We propose a variational approach that employs a generalized principle of virtual work to estimate both the mechanical response and the changes in living bone tissue during the remodeling process. This approach provides an explanation for the adaptive regulation of the bone substructure in the context of orthotropic material symmetry. We specifically focus upon the crucial gradual adjustment of bone tissue as a structural material that adapts its mechanical features, such as materials stiffnesses and microstructure, in response to the evolving loading conditions. We postulate that the evolution process relies on a feedback mechanism involving multiple stimulus signals. The mechanical and remodeling behavior of bone tissue is clearly a complex process that is difficult to describe within the framework of classical continuum theories. For this reason, a generalized continuum elastic theory is employed as a proper mathematical context for an adequate description of the examined phenomenon. To simplify the investigation, we considered a two-dimensional problem. Numerical simulations have been performed to illustrate bone evolution in a few significant cases: the bending of a rectangular cantilever plate and a three-point flexure test. The results are encouraging because they can replicate the optimization process observed in bone remodeling. The proposed model provides a likely distribution of stiffnesses and accurately represents the arrangement of trabeculae macroscopically described by the orthotropic symmetry directions, as supported by experimental evidence from the trajectorial theory.

Toward a Theory of Long-Term Post-Initial Public Offering Growth Trajectories

Toward a Theory of Long-Term Post-Initial Public Offering Growth Trajectories

표집변이성에 대한 추론 능력 함양을 위한 학습 경로 설계 연구

Our understanding of statistical inference is based on our understanding of the concept of sampling variability. In this study, we aimed to explore learning trajectory that would help students meaningfully construct concepts related to sampling variability under this assumption. For this purpose, in this study, based on hypothetical learning trajectory theory, we designed a learning trajectory that is expected to develop students’ reasoning about sampling variability. We qualitatively analyzed the results of a teaching experiment conducted for a group of preparatory teachers according to the guidance of the learning trajectory designed in this study. As a result, The participants were able to generate the hypothesis that sample medians obtained through a random sampling process were normally distributed around the population median. The participants were then able to generate the hypothesis that the larger the sample size, the smaller the range of distribution of the sample median. Furthermore, it is possible to generate the hypothesis that the center of the distribution of the sample median is determined by the population median, and the range of the distribution of the sample median is determined by the sample size and the interquartile range of the population. In addition, based on the results of retrospective analysis of the difference between the hypothetical learning trajectory and the actual learning trajectory, we proposed a modification of the initially designed hypothetical learning trajectory.

Increasing the accuracy of finding the coordinates of sea mines by means of kinematic design

The issue of demining reservoirs, rivers and sea raids and ports, which is relevant for Europe during the period of active deployment of military confrontations on its territory, is considered. Only in the maritime territorial waters of Ukraine and in the water areas of its freshwater reservoirs and rivers, during the year of the war, the enemy laid up to a thousand different mines. Demining of the Ukrainian water spaces of the sea, reservoirs and rivers is an important social and economic problem, the solution of which does not tolerate delay and waiting for the full end of hostilities.
 The purpose of the work is the development of principle schemes for optimizing the spatial movements of search and mine clearance vessels and the creation of algorithms for calculating the precise coordinates of the spatial location of floating, anchor and bottom mines by means of kinematic design.
 The research methodology was the application of the theory of mapping coordinates and trajectories of spatial movements of moving objects by means of graphic geometry, taking into account the specifics and dynamic features of kinematic design.
 A schematic diagram of the spatial location of search trawlers and UAVs or auxiliary search floats when searching for mines has been developed. Mathematical dependencies have also been established for the precise calculation of the coordinates of detected mines based on the data of the applied theory and kinematic design schemes. For the search for floating mines, the optimal trajectory of search movements of unmanned aerial vehicles along the Archimedean spiral is proposed. The optimal number of aircraft that search for floating mines at the same time has been determined. As one of the most effective options for the disposal of mines, their detonation with warheads dropped from an aerial liquidator drone has been proposed.
 The main result of the study is the creation of a methodology for calculating the refined coordinates of the search for floating, anchor and bottom mines in combination with the optimization of the trajectories of the search movements of aerial and floating search vehicles along the Archimedean spiral. This ensures not only a 25-30% increase in surveyed and demined areas, but also a proportional saving of fuel due to a reduction in the number of crossings of search trawlers. It has been established that at speeds of spatial movements of search aircraft or auxiliary floating means of 5÷5.5 m/s, using the proposed search scheme, it is possible to survey up to 6 square kilometers of sea water area every hour. At the same time, it is possible to save up to a third of the cost of expensive fuel due to the reduction of movements of the trawler boat.

Types of work young adults perform to adjust to a cancer diagnosis and treatment.

e24179 Background: Patients and their caregivers perform work (i.e., demanding and arduous labor that takes resources and coordination to address) to manage their illness, relationships, and lives. A growing body of psychosocial research has investigated the communication work performed by young adults (18-39 years old at diagnosis; YAs) and their caregivers as they adjust to cancer treatment and survivorship. However, to our knowledge, no studies have examined how the four types of work identified through Theory of Illness Trajectories (i.e., everyday, illness-related, biographical, and communication) interact within cancer survivorship. Thus, the study purpose was to investigate how and why YAs describe their efforts to manage life along the cancer trajectory as work or labor. Methods: We conducted a qualitative secondary analysis leveraging three separate qualitative interview datasets that sought to describe and explain similar psychosocial aspects of the YA cancer experience. Two specific interview questions: 1) “What advice would you give to another person your age who received a similar diagnosis?” and 2) “What did you learn from your cancer experience that you wish you knew when you were diagnosed?” shaped our thematic analysis. We applied the Theory of Illness Trajectories in the open coding phase, where everyday-life work referred to recurring existing responsibilities (e.g., employment, childcare); illness work related to cancer-management tasks like taking medication and seeing physicians; biographical work involved one’s cognitive efforts to reconstruct their identity, and communication work involved the demanding use of communication to manage identities, share information, or solicit support. During axial coding, each author reviewed one-third of the data individually, making note of units that could be classified as themes related to each type of work. Results: A total of 112 participants completed qualitative interviews across the three studies. Most (71%) were female, and mean age was 26 years. Most received a diagnosis of lymphoma (33.0%), leukemia (17.9%), and breast cancer (11.6%). Data analyses are still ongoing; we are currently meeting regularly to reach consensus on our axial codes. Our final abstract will include findings from our selective coding phase, which will allow us to examine comparisons and interactions between types of work. Conclusions: Additional goals of our innovative qualitative secondary analysis are to a) to identify the most salient subtypes of biographical, illness-related, everyday, and communication work in the YA cancer context and b) to better understand how the four types of work described by theory of illness trajectories interact and whether they facilitate or hinder the performance of additional types of work.