Model driven

  • 文章类型: Journal Article
    路径规划是机器人学的一个重要研究领域。与其他路径规划算法相比,快速探索随机树(RRT)算法同时具有搜索和随机抽样特性,因此具有更多的潜力来生成可以平衡全局最优和局部最优的高质量路径。本文回顾了2021-2023年基于RRT的改进算法的研究,包括理论改进和应用实现。在理论层面,分支战略改进,抽样策略的改进,后处理改进,突出显示了模型驱动的RRT,在应用层面,RRT在焊接机器人下的应用场景,装配机器人,搜索和救援机器人,手术机器人,自由漂浮的太空机器人,和检测机器人是详细的,最后,总结了RRT在理论和应用层面面临的诸多挑战。这篇综述表明,尽管基于RRT的改进算法在大规模场景中具有优势,实时性能,和不确定的环境,一些难以定量描述的策略可以基于模型驱动的RRT来设计,基于RRT的改进算法仍然存在难以设计超参数和泛化能力弱的问题,在实际应用层面,控制器等硬件的可靠性和准确性,执行器,传感器,通信,电源和数据采集效率都对大规模非结构化场景下RRT的长期稳定性提出了挑战。作为自主机器人的一部分,RRT路径规划性能的上限还取决于机器人的定位和场景建模性能,在多机器人协作中仍然存在架构和战略选择,除了必须面对的伦理和道德。为了解决上述问题,我相信多类型机器人协作,人机协作,实时路径规划,超参数的自整定,面向任务或应用场景的算法和硬件设计,高度动态环境中的路径规划是未来的发展趋势。
    Path planning is an crucial research area in robotics. Compared to other path planning algorithms, the Rapidly-exploring Random Tree (RRT) algorithm possesses both search and random sampling properties, and thus has more potential to generate high-quality paths that can balance the global optimum and local optimum. This paper reviews the research on RRT-based improved algorithms from 2021 to 2023, including theoretical improvements and application implementations. At the theoretical level, branching strategy improvement, sampling strategy improvement, post-processing improvement, and model-driven RRT are highlighted, at the application level, application scenarios of RRT under welding robots, assembly robots, search and rescue robots, surgical robots, free-floating space robots, and inspection robots are detailed, and finally, many challenges faced by RRT at both the theoretical and application levels are summarized. This review suggests that although RRT-based improved algorithms has advantages in large-scale scenarios, real-time performance, and uncertain environments, and some strategies that are difficult to be quantitatively described can be designed based on model-driven RRT, RRT-based improved algorithms still suffer from the problems of difficult to design the hyper-parameters and weak generalization, and in the practical application level, the reliability and accuracy of the hardware such as controllers, actuators, sensors, communication, power supply and data acquisition efficiency all pose challenges to the long-term stability of RRT in large-scale unstructured scenarios. As a part of autonomous robots, the upper limit of RRT path planning performance also depends on the robot localization and scene modeling performance, and there are still architectural and strategic choices in multi-robot collaboration, in addition to the ethics and morality that has to be faced. To address the above issues, I believe that multi-type robot collaboration, human-robot collaboration, real-time path planning, self-tuning of hyper-parameters, task- or application-scene oriented algorithms and hardware design, and path planning in highly dynamic environments are future trends.
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  • 文章类型: Journal Article
    自发性不良事件报告(SAER)数据库在上市后药物监测中发挥着至关重要的作用。然而,传统的无模型不相称性分析受到亚组和混杂因素调查不足的挑战.这些问题导致SAER数据挖掘中的严重低精度和偏差。
    提出了模型驱动报告赔率比(MD-ROR),以弥合SAER数据库和可解释模型之间的差距,以探索个体和混杂效应。MD-ROR以精心设计的模型为基础,而不是一个2×2的交叉表,用于估计AE-药物信号。因此,可以基于这些模型对个体效应和混杂效应进行参数化。我们采用了模拟数据和FDA不良事件报告系统(FAERS)数据库。
    模拟数据表明,通过MD-ROR估计的亚组效应是无偏且有效的。此外,与粗ROR相比,调整后的MD-ROR对混杂偏差表现出更大的稳健性。将我们的方法应用于FAERS数据库表明,与男性相比,女性中咪达唑仑引起的药物相互作用和心脏不良事件发生率更高。
    该研究强调,MD-ROR有望作为调查SAER数据库中个体和混杂效应的方法。
    UNASSIGNED: Spontaneous Adverse Event Reporting (SAER) databases play a crucial role in post-marketing drug surveillance. However, the traditional model-free disproportionality analysis has been challenged by the insufficiency in investigating subgroup and confounders. These issues result in significant low-precision and biases in data mining for SAER.
    UNASSIGNED: The Model-Driven Reporting Odds Ratio (MD-ROR) was proposed to bridge the gap between SAER database and explainable models for exploring individual and confounding effects. MD-ROR is grounded in a well-designed model, rather than a 2 × 2 cross table, for estimating AE-drug signals. Consequently, individual and confounding effects can be parameterized based on these models. We employed simulation data and the FDA Adverse Event Reporting System (FAERS) database.
    UNASSIGNED: The simulated data indicated the subgroup effects estimated by MD-ROR were unbiased and efficient. Moreover, the adjusted-MD-ROR demonstrated greater robustness against confounding biases than the crude ROR. Applying our method to the FAERS database suggested higher occurrences of drug interactions and cardiac adverse events induced by Midazolam in females compared to males.
    UNASSIGNED: The study underscored that MD-ROR holds promise as a method for investigating individual and confounding effects in SAER databases.
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  • 文章类型: Journal Article
    针对毫米波宽带系统中由于未能考虑“波束斜视”效应而导致低信噪比下估计精度低的问题,提出了一种基于模型驱动的毫米波大规模MIMO宽带系统信道估计方法。该方法考虑了“波束斜视”效应,并将迭代收缩阈值算法应用于深度迭代网络。首先,通过训练数据学习,将毫米波信道矩阵变换到具有稀疏特征的变换域,得到稀疏矩阵。其次,在波束域去噪阶段,提出了一种基于注意力机制的收缩阈值网络。网络根据特征自适应选择一组最佳阈值,可以应用于不同的信噪比,达到更好的去噪效果。最后,残差网络和收缩阈值网络联合优化,加快网络的收敛速度。仿真结果表明,在不同信噪比下,收敛速度提高了10%,信道估计精度平均提高了17.28%。
    Aiming at the problem of low estimation accuracy under a low signal-to-noise ratio due to the failure to consider the \"beam squint\" effect in millimeter-wave broadband systems, this paper proposes a model-driven channel estimation method for millimeter-wave massive MIMO broadband systems. This method considers the \"beam squint\" effect and applies the iterative shrinkage threshold algorithm to the deep iterative network. First, the millimeter-wave channel matrix is transformed into a transform domain with sparse features through training data learning to obtain a sparse matrix. Secondly, a contraction threshold network based on an attention mechanism is proposed in the phase of beam domain denoising. The network selects a set of optimal thresholds according to feature adaptation, which can be applied to different signal-to-noise ratios to achieve a better denoising effect. Finally, the residual network and the shrinkage threshold network are jointly optimized to accelerate the convergence speed of the network. The simulation results show that the convergence speed is increased by 10% and the channel estimation accuracy is increased by 17.28% on average under different signal-to-noise ratios.
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  • 文章类型: Journal Article
    基于空地集成网络(SGIN)的网络物理系统(CPS)使CPS能够突破空间中的地理限制。因此,为SGIN的新技术验证和网络安全策略评估提供测试平台是必要的。用户行为仿真技术能够有效支持测试平台的构建。鉴于内在的动态变化,不同的行为,和SGIN用户的大规模特征,提出了基于云平台的用户行为仿真技术。首先,设计了SGIN用户行为的动态仿真体系结构。然后,提出了群体用户行为模型实时驱动的正常用户行为仿真策略,这可以提高仿真的保真度。此外,采用流氓用户行为仿真技术,基于交通回放,执行安全评估。具体来说,本研究将虚拟互联网协议(IP)技术和epoll模型有效地集成在一起,以解决大规模仿真和计算开销之间的矛盾。实验结果表明,该策略满足多样化和高保真的动态用户行为仿真的要求,达到了正常用户10万级并发通信和流氓用户10万级并发攻击的仿真规模。
    Cyber-physical systems (CPSs) based on space-ground integrated networks (SGINs) enable CPSs to break through geographical restrictions in space. Therefore, providing a test platform is necessary for new technical verification and network security strategy evaluations of SGINs. User behavior emulation technology can effectively support the construction of a test platform. Given the inherent dynamic changes, diverse behaviors, and large-scale characteristics of SGIN users, we propose user behavior emulation technology based on a cloud platform. First, the dynamic emulation architecture for user behavior for SGINs is designed. Then, normal user behavior emulation strategy driven by the group user behavior model in real time is proposed, which can improve the fidelity of emulation. Moreover, rogue user behavior emulation technology is adopted, based on traffic replay, to perform the security evaluation. Specifically, virtual Internet Protocol (IP) technology and the epoll model are effectively integrated in this investigation to resolve the contradiction between large-scale emulation and computational overhead. The experimental results demonstrate that the strategy meets the requirement of a diverse and high-fidelity dynamic user behavior emulation and reaches the emulation scale of 100,000-level concurrent communication for normal users and 100,000-level concurrent attacks for rogue users.
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