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BackgroundTemporal dynamics during the early adulthood transition among children in out-of-home care is a neglected research area, leaving the possibility of coping with childhood adversity over time a poorly understood topic.ObjectiveTo explore early adulthood education and employment trajectories among young adults who experienced out-of-home care during childhood and to examine how various care history factors predict these trajectories.ParticipantsWe use longitudinal birth cohort data comprising individual-level information from national registers of all children born in Finland in 1987 (N = 59,476, of whom 1893 were in care).Setting and methodsWe use trajectory clustering from a previous study on the 1987 birth cohort to compare trajectories between children in care and a propensity score–matched group of peers never in care. We investigated the association between care history factors and trajectories with multinomial logistic regression modeling.ResultsCompared with the matched peer group, children in care were less likely to enter trajectories characterized by education and employment (38%) and more likely to enter trajectories involving early parenthood (14%) or long periods of fragmented social assistance benefit receipt and unemployment (21%). Those on early parenthood trajectories were almost exclusively women, whereas those receiving social assistance benefits and experiencing unemployment for lengthy periods were mostly men. Entering disadvantaged trajectories was associated with, inter alia, placement as an adolescent, residential care, and aging out of care.ConclusionThe study demonstrates the relevance of examining longitudinal trajectories in children in care’s early adulthood. Many young adults with care experience need support in education and employment beyond young adult age. 相似文献
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随着各种各样移动设备的普及,轨迹隐私保护问题变得日益严峻,作为轨迹隐私保护的一个方向,国内外开始慢慢建立起一些较为成熟的度量机制,常见的有基于k-匿名保护机制的隐私度量方法、基于跟踪的度量方法、针对特定匿名系统的轨迹隐私度量方法等。文章在现有研究的基础上构建了了一种基于假数据轨迹隐私保护技术的隐私度量标准,从发布假轨迹上点之间的关联性、发布数据所包含信息的精确度以及攻击者所拥有背景知识多少三个方面进行轨迹隐私保护度的全面度量。 相似文献
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The association between child sexual abuse (CSA) and risk for re-victimization is well-documented; however, less is known about the temporal progression of re-victimization experiences over the early life-course among CSA survivors, and whether this differs from that of those without known sexual abuse histories. This study investigated whether there are distinct temporal pathways of interpersonal re-victimization between the ages of 10–25 years among medically confirmed CSA cases, and considered whether abuse variables, re-victimization variables, and the presence of other adverse outcomes, were associated with heterogeneity in re-victimization pathways. The data were collected as part of a large-scale data-linkage study in which the medical records of 2759 cases of contact-CSA between 1964 and 1995 were linked, between 13 and 44 years following abuse, to police and public psychiatric databases; cases were compared to a matched community sample (n = 2677). Using a subsample of 510 (401 victims; 109 comparisons) individuals with an interpersonal (re)victimization history, we examined the aggregate ‘age-(re)victimization’ curves for CSA victims and comparisons, respectively. Further, we applied longitudinal latent class analysis to explore heterogeneity in re-victimization trajectories among abuse survivors across their early life-course. Four latent pathways were identified, labeled: Normative; Childhood-Limited; Emerging-Adulthood; and Chronic re-victimization trajectories. Older age at abuse, a criminal history, and mental health problems were uniquely predictive of membership to the more problematic and persistent re-victimization trajectories. Findings indicate that individuals exposed to CSA during adolescence may be particularly vulnerable to poorer re-victimization trajectories, characterized by multiple risk indices, and thus may warrant increased service provision. 相似文献
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针对6R型机械臂运动学进行了研究。首先采用D-H法建立机械臂关节坐标系并确定其连杆参数,应用MATLAB软件中的Robotics Toolbox仿真工具箱建立该机械臂模型,其次对机械臂进行轨迹规划研究和运动学仿真,最后,基于机械臂运动学模型应用可操作度指标分析机械臂的灵巧性能,本文阐述了机械臂运动学仿真的一般规律,由仿真得出的结果可知,本文的研究对于关节型机械臂的运动学仿真具有重要意义。 相似文献
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在解析几何中,详细讨论了平行于某一非渐近方向的一族弦的中点轨迹,有很多好的性质;通过对二次曲线过定点的弦的中点进行讨论,得出其轨迹方程,给出简单的应用,并得出几个较好的性质. 相似文献
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四轮全向机器人是一个复杂的四维冗余系统,其轨迹跟踪控制性能极易受到模型不确定性及外界干扰的影响。针对这一问题,本文提出一种基于动力学模型的四轮全向机器人滑模轨迹跟踪控制方法。首先,通过输入变换将复杂的四维冗余机器人系统模型转化为三维模型,然后针对模型不确定性及外界扰动,采用滑模控制算法进行轨迹跟踪控制。仿真结果表明,该方法能够有效抑制外界干扰,同时降低模型不确定性的影响,机器人能够很好地跟踪期望轨迹,跟踪速度快,跟踪精度高。 相似文献
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终端区航空器的异常轨迹检测是一个崭新的研究领域。异常轨迹检测常使用基于全局特征、轨迹片段、分类器的检测方法,后续又出现了基于划分、蚁群算法、轨迹模型、人工免疫等一系列的改进方法,各具特点。但是以上的方法在准确性、复杂度、评价方法等方面依然存在不足,需要进一步改进和创新。此领域具有良好的发展和应用前景。 相似文献
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A new approach to control the attitude of a quadrotor UAV in terms of the exponential coordinates is developed in this paper. The exponential coordinate is a minimal representation of the rotation matrix, but it can avoid singularities. Since the quadrotor UAV can be considered as a rigid body aircraft, the analytic closed-form expressions of a rigid body's attitude kinematics are derived from differential of exponential on SO(3). Furthermore, based on the exponential expressions of attitude kinematics, the controller of a fully actuated rigid body is designed using trajectory linearization control method. The overall attitude controller contains two loops, which are designed according to the torque equation and the angular velocity equation respectively. In the numerical simulation, the proposed attitude controller is compared to a controller in the Euler angles, showing that singularities induced by Euler angles are avoided by using exponential coordinates. The robustness test of the attitude controller is also demonstrated in the simulation. The simulation results indicate that the proposed method can be applied to the attitude tracking control of an aerial robot especially when the robot needs to make aggressive maneuverings. 相似文献
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本文提出了一种基于SIFT算法和相对定向直接解算方法的视觉定位匹配方法,可解决SIFT算法无法准确定位的问题。 SIFT算法通过构建尺度空间、检测极值点、确定关键点等步骤为含有位置信息的视觉图片序列生成关键特征点,然后,计算每个关键特征点周围图像区域的旋转不变纹理特征,并将其作为该关键特征点的描述,进行SIFT初匹配,利用得到的相匹配坐标进行相对定向直接解算,从而得到载体在运动中的位置坐标和运动轨迹。实验结果表明,本方法能够较为准确的得到物体在运动中的位置及其运动轨迹,误差较小,有很好的应用性。 相似文献