Effect Of Different Trajectories Research Articles

Trajectories of Loneliness During Adolescence Predict Subsequent Symptoms of Depression and Positive Wellbeing

There is a need to identify the outcomes of changes in loneliness during adolescence, and to consider this within a multidimensional framework of loneliness. This study considered the effects of different trajectories of change in Isolation Loneliness and in Friendship Loneliness upon both positive wellbeing and symptoms of depression. To achieve this, 1782 (43% female; 12.92 years old at the start of the study, SD = 1.60) young people took part in a longitudinal study with four data points across 2 years. Four Isolation Loneliness trajectories and five Friendship Loneliness trajectories were identified. Youth who experienced low levels of Isolation Loneliness that subsequently increased appear to be at particular risk for poor outcomes. Similarly, initially high levels of Friendship Loneliness that decreased rapidly, or which began at a low level and only increased marginally, seem to also be a risk. Loneliness is a multi-dimensional construct and its development during adolescence impacts upon young people’s depressive symptomatology and positive mental wellbeing.

Investigating the Effects of Polynomial Trajectories on Energy Consumption of Quadrotors

This article focuses on investigating the effect of quadrotor's trajectory, especially polynomial trajectories, on its energy consumption. First, model-free expressions for power and energy quotients are introduced to relate quadrotor's power and energy directly to its acceleration. This allows to qualitatively estimate quadrotor's energy consumption and compare the effect of different trajectories on energy consumption of identical or different quadrotors independent of quadrotor's manufacturing specifications. Then, polynomial trajectories are analytically investigated for rest-to-rest 1-D scenarios. Scenarios in 3-D with arbitrary kinematic boundary conditions are analyzed via Monte Carlo Simulations with a sample of 10 000 sets of arbitrary boundary conditions. Polynomial trajectories are compared to energy-minimized trajectories in the literature. The results show that increasing the degree of the polynomial increases quadrotor's energy consumption. Moreover, this article suggests using minimum acceleration trajectories as energy-efficient polynomial trajectories. Finally, the results are validated experimentally.

Stiffness-based trajectory planning of a 6-DOF cable-driven parallel manipulator

The stiffness of the cable-driven parallel manipulator is usually poor because of the cable flexibility, and the existing methods on trajectory planning mainly take the minimum time and the optimal energy into account, not the stiffness. To solve it, the effects of different trajectories on stiffness are studied for a six degree-of-freedom cable-driven parallel manipulator, according to the kinematic model and the dynamic model. The condition number and the minimum eigenvalue of the dimensionally homogeneous stiffness matrix are selected as performance indices to analyze the stiffness changes during the motion. The simulation experiments are implemented on a six degree-of-freedom cable-driven parallel manipulator, to study the stiffness of three different trajectory planning approaches such as S-type velocity profile, quintic polynomial, and trigonometric function. The accelerations of different methods are analyzed, and the stiffness performances for the methods are compared after planning the point-to-point straight and the curved trajectories. The simulation results indicate that the quintic polynomial and S-type velocity profile have the optimal performance to keep the stiffness stable during the motion control and the travel time of the quintic polynomial can be optimized sufficiently while keeping stable.

Exploring future agricultural development and biodiversity in Uganda, Rwanda and Burundi: a spatially explicit scenario-based assessment

Competition for land is increasing as a consequence of the growing demands for food and other commodities and the need to conserve biodiversity and ecosystem services. Land conversion and the intensification of current agricultural systems continues to lead to a loss of biodiversity and trade-offs among ecosystem functions. Decision-makers need to understand these trade-offs in order to better balance different demands on land and resources. There is an urgent need for spatially explicit information and analyses on the effects of different trajectories of human-induced landscape change in biodiversity and ecosystem services. We assess the potential implications of a set of plausible socio-economic and climate scenarios for agricultural production and demand and model-associated land use and land cover changes between 2005 and 2050 to assess potential impacts on biodiversity in Uganda, Rwanda and Burundi. We show that different future socio-economic scenarios are consistent in their projections of areas of high agricultural development leading to similar spatial patterns of habitat and biodiversity loss. Yet, we also show that without protected areas, biodiversity losses are higher and that expanding protected areas to include other important biodiversity areas can help reduce biodiversity losses in all three countries. These results highlight the need for effective protection and the potential benefits of expanding the protected area network while meeting agricultural production needs.

Trajectory Analysis Using Static Patches for Magnetic Particle Imaging

Magnetic particle imaging (MPI) is an imaging technique based on the determination of magnetic material by moving a field-free point along specified trajectories, which are used to sample the field of view. Due to technical and safety reasons, the field of view is limited in size. To enlarge the size of the field of view, trajectory patches are used, which are sampled separately and combined consecutively to an entire field of view. The aim of this paper is to analyze the effect of different trajectories combined with the patch approach. In addition, an empiric study is performed to analyze the influence of overlapped patches on each trajectory combined with cutoff as postprocessing method. As a follow-up, a new patch formation of the radial trajectory based on a phase shift between each of the patches is introduced. Finally, it can be shown that the Lissajous trajectory, which is commonly used for MPI, provides appropriate results. However, the results of overlapped patches with a circular trajectory increase spatial resolution.

ESWC: Efficient Scheduling for the Mobile Sink in Wireless Sensor Networks with Delay Constraint

This paper exploits sink mobility to prolong the network lifetime in wireless sensor networks where the information delay caused by moving the sink should be bounded. Due to the combinational complexity of this problem, most previous proposals focus on heuristics and provable optimal algorithms remain unknown. In this paper, we build a unified framework for analyzing this joint sink mobility, routing, delay, and so on. We discuss the induced subproblems and present efficient solutions for them. Then, we generalize these solutions and propose a polynomial-time optimal algorithm for the origin problem. In simulations, we show the benefits of involving a mobile sink and the impact of network parameters (e.g., the number of sensors, the delay bound, etc.) on the network lifetime. Furthermore, we study the effects of different trajectories of the sink and provide important insights for designing mobility schemes in real-world mobile WNNs.

Chronology of postural and focal component of muscular activity during manual wheelchair propulsion initiation: effect of different trajectories and velocities

Chronology of postural and focal component of muscular activity during manual wheelchair propulsion initiation: effect of different trajectories and velocities

Suture Button Suspension following Trapeziectomy in a Cadaver Model

The safety and the effects of different trajectories on thumb motion of suture-button suspensionplasty post-trapeziectomy are not known. In a cadaveric model, thumb range of motion, trapeziectomy space height, and distance between the device and nerve to the first dorsal interosseous muscle (first DI) were measured for proximal and distal trajectory groups. Proximal trajectory was defined as a suture button angle directed from the thumb metacarpal to the second metacarpal at a trajectory less than 60° from the horizontal; distal trajectory was defined as a suture button angle directed from the thumb metacarpal to the second metacarpal at a trajectory of greater than 60° from the horizontal (Fig.1). There were no significant differences in range of motion and trapeziectomy space height between both groups. The device was significantly further away from the nerve to the first DI in the proximal trajectory group compared to the distal trajectory group, but was still safely away from the nerve in both groups (greater than 1cm). These results suggest that the device placement in either a proximal or distal location on the second metacarpal will yield similar results regarding safety and thumb range of motion.

Needle insertion into soft tissue: A survey

Needle insertion in soft tissue has attracted considerable attention in recent years due to its application in minimally invasive percutaneous procedures such as biopsies and brachytherapy. This paper presents a survey of the current state of research on needle insertion in soft tissue. It examines the topic from several aspects, e.g. modeling needle insertion forces, modeling tissue deformation and needle deflection during insertion, robot-assisted needle insertion, and the effect of different trajectories on tissue deformation. All studies show that the axial force of a needle during insertion in soft tissue is the summation of different forces distributed along the needle shaft such as stiffness force, frictional force and cutting force. Some studies have modeled these forces. The force data in some procedures is used for identifying tissue layers as the needle is inserted or for path planning. Needle deflection and tissue deformation are major problems for accurate needle insertion and attempts have been made to model them. Using current models several insertion techniques have been developed which are briefly reviewed in this paper.

Control of soft tissue deformation during robotic needle insertion

Accurate needle insertion into soft, inhomogeneous tissue is of practical interest because of its importance in percutaneous therapies. In procedures that involve multiple needle insertions such as transrectal ultrasound‐guided prostate brachytherapy, it is important to reduce tissue deformation before puncture and during needle insertion. In order to reduce this deformation, we have studied the effect of different trajectories for a 2‐DOF (degrees of freedom) robot performing needle insertion in soft tissue. To obtain an optimum trajectory, we have compared tissue indentation and frictional forces for different trajectories. According to the results of our experiments, infinitesimal force per tissue displacement is a useful parameter for online trajectory update. In addition, the results show that axial rotation can reduce tissue indentation before puncture and frictional forces after puncture. Our proposed position/force controller is shown to provide considerable improvement in performance with regard to minimizing tissue deformation before puncture.