现代优化策略，例如进化算法，蚂蚁菌落算法，贝叶斯优化技术等。带有几个参数，可在优化过程中引导其行为。为了获得高性能算法实例，已经开发了自动化算法配置技术。最受欢迎的工具之一是IRACE，它可以评估顺序种族中的配置，利用迭代统计测试来丢弃性能不佳的配置。在比赛结束时，使用贪婪的截断选择，从未丢弃的幸存者配置中选择了一组精英配置。我们研究两种替代选择方法：一种是保持最佳幸存者，并从一组幸存者中随机选择其余配置，而另一个则应用熵以最大程度地提高精英的多样性。这些方法经过测试，用于调整蚂蚁菌落优化算法，以解决旅行销售人员问题以及二次分配问题，并为满足性问题调整精确的树搜索求解器。实验结果表明，与IRACE的默认选择相比，测试的基准测试结果有所改善。此外，获得的结果表明，非专业人士可以获得多种算法配置，这鼓励我们探索更广泛的解决方案以了解算法的行为。

Benchmarking is a key aspect of research into optimization algorithms, and as such the way in which the most popular benchmark suites are designed implicitly guides some parts of algorithm design. One of these suites is the black-box optimization benchmarking (BBOB) suite of 24 single-objective noiseless functions, which has been a standard for over a decade. Within this problem suite, different instances of a single problem can be created, which is beneficial for testing the stability and invariance of algorithms under transformations. In this paper, we investigate the BBOB instance creation protocol by considering a set of 500 instances for each BBOB problem. Using exploratory landscape analysis, we show that the distribution of landscape features across BBOB instances is highly diverse for a large set of problems. In addition, we run a set of eight algorithms across these 500 instances, and investigate for which cases statistically significant differences in performance occur. We argue that, while the transformations applied in BBOB instances do indeed seem to preserve the high-level properties of the functions, their difference in practice should not be overlooked, particularly when treating the problems as box-constrained instead of unconstrained.

每种算法选择旨在为给定的问题实例和给定的性能标准推荐一种或几种合适的算法，这些算法有望在特定设置中表现良好。选择是经典的离线完成的，使用有关问题实例或在专用功能提​​取步骤中从实例中提取的功能的公开可用信息。这忽略了算法在优化过程中积累的有价值的信息。在这项工作中，我们提出了一种替代性的在线算法选择方案，我们每次算法选择该方案。在我们的方法中，我们使用默认算法启动优化，在经过一定数量的迭代之后，从该初始优化器的观察到的轨迹中提取实例功能，以确定是否切换到另一个优化器。我们使用CMA-E作为默认求解器测试这种方法，以及六个不同优化器的投资组合作为可切换的潜在算法。与其他关于在线人均算法选择的最新工作相反，我们使用在第一个优化阶段累积的信息进行了第二个优化器。我们表明，我们的方法的表现优于静态算法选择。我们还基于探索性景观分析和分别对CMA-ES内部状态变量的探索性景观分析和时间序列分析进行比较。我们表明，这两种功能集的组合为我们的测试用例提供了最准确的建议，该建议是从可可平台的BBOB功能套件和Nevergrad平台的Yabbob Suite中获取的。

到目前为止，景观感知算法选择方法主要依靠景观特征提取作为预处理步骤，而与投资组合中优化算法的执行无关。这引入了许多实用应用的计算成本的重要开销，因为通过采样和评估手头的问题实例提取和计算功能，与优化算法在其搜索轨迹中所执行的功能类似。如Jankovic等人所建议的。 （EVOAPPS 2021），基于轨迹的算法选择可以通过从求解器在优化过程中对求解器进行采样和评估的点来计算景观特征来规避昂贵的特征提取问题。以这种方式计算的功能用于训练算法性能回归模型，然后在该模型上构建每运行算法选择器。在这项工作中，我们将基于轨迹的方法应用于五种算法的投资组合。我们研究了在固定的功能评估预算之后预测不同算法性能的情况下，性能回归和算法选择模型的质量和准确性。我们依靠使用相同功能评估的上述预算的一部分计算出的问题实例的景观特征。此外，我们考虑一次在求解器之间切换一次的可能性，这要求它们要热身启动，即当我们切换时，第二求解器继续使用第一个求解器收集的信息来继续适当地初始化优化过程。在这种新背景下，我们展示了基于轨迹的每算法选择的有前途的表现，并启动了温暖。

我们展示IohexPerimener，Iohprofiler项目的实验模块，旨在为基准测试迭代优化启发式提供易于使用和高度可定制的工具箱，例如进化和遗传算法，本地搜索算法，贝叶斯优化技术等。Iohexperimenter可以用作独立工具或作为基准管道的一部分，用于使用IOHPOFILER（如IOHANALYZER）的其他组件，该模块用于交互式性能分析​​和可视化。 iohExperimenter在优化问题和求解器之间提供了有效的接口，同时允许优化过程的粒度测井。这些日志与现有的交互式数据分析工具完全兼容，这显着加快了基准管道的部署。 iohexperimener的主要组成部分是构建定制的问题套件和各种日志记录选项的环境，允许用户转向数据记录的粒度。

基准和性能分析在理解迭代优化启发式（IOHS）的行为中发挥着重要作用，例如本地搜索算法，遗传和进化算法，贝叶斯优化算法等。然而，这项任务涉及手动设置，执行和分析实验单独的基础，这是艰苦的，可以通过通用和设计精心设计的平台来缓解。为此，我们提出了Iohanalyzer，一种用于分析，比较和可视化IOH的性能数据的新用户友好的工具。在R和C ++中实现，Iohanalyzer是完全开源的。它可以在Cran和GitHub上获得。 Iohanalyzer提供有关固定目标运行时间的详细统计信息以及具有实际值的Codomain，单目标优化任务的基准算法的固定预算性能。例如，在多个基准问题上的性能聚合是可能的，例如以经验累积分布函数的形式。 Iohanalyzer在其他性能分析包上的主要优点是其高度交互式设计，允许用户指定对其实验最有用的性能测量，范围和粒度，以及不仅分析性能迹线，还可以分析演变动态状态参数。 Iohanalyzer可以直接从主基准平台处理性能数据，包括Coco平台，JOVERRAD，SOS平台和iohExperenter。提供R编程接口，供用户更倾向于对实现的功能进行更精细的控制。

While the brain connectivity network can inform the understanding and diagnosis of developmental dyslexia, its cause-effect relationships have not yet enough been examined. Employing electroencephalography signals and band-limited white noise stimulus at 4.8 Hz (prosodic-syllabic frequency), we measure the phase Granger causalities among channels to identify differences between dyslexic learners and controls, thereby proposing a method to calculate directional connectivity. As causal relationships run in both directions, we explore three scenarios, namely channels' activity as sources, as sinks, and in total. Our proposed method can be used for both classification and exploratory analysis. In all scenarios, we find confirmation of the established right-lateralized Theta sampling network anomaly, in line with the temporal sampling framework's assumption of oscillatory differences in the Theta and Gamma bands. Further, we show that this anomaly primarily occurs in the causal relationships of channels acting as sinks, where it is significantly more pronounced than when only total activity is observed. In the sink scenario, our classifier obtains 0.84 and 0.88 accuracy and 0.87 and 0.93 AUC for the Theta and Gamma bands, respectively.

There are multiple scales of abstraction from which we can describe the same image, depending on whether we are focusing on fine-grained details or a more global attribute of the image. In brain mapping, learning to automatically parse images to build representations of both small-scale features (e.g., the presence of cells or blood vessels) and global properties of an image (e.g., which brain region the image comes from) is a crucial and open challenge. However, most existing datasets and benchmarks for neuroanatomy consider only a single downstream task at a time. To bridge this gap, we introduce a new dataset, annotations, and multiple downstream tasks that provide diverse ways to readout information about brain structure and architecture from the same image. Our multi-task neuroimaging benchmark (MTNeuro) is built on volumetric, micrometer-resolution X-ray microtomography images spanning a large thalamocortical section of mouse brain, encompassing multiple cortical and subcortical regions. We generated a number of different prediction challenges and evaluated several supervised and self-supervised models for brain-region prediction and pixel-level semantic segmentation of microstructures. Our experiments not only highlight the rich heterogeneity of this dataset, but also provide insights into how self-supervised approaches can be used to learn representations that capture multiple attributes of a single image and perform well on a variety of downstream tasks. Datasets, code, and pre-trained baseline models are provided at: https://mtneuro.github.io/ .

The ability to convert reciprocating, i.e., alternating, actuation into rotary motion using linkages is hindered fundamentally by their poor torque transmission capability around kinematic singularity configurations. Here, we harness the elastic potential energy of a linear spring attached to the coupler link of four-bar mechanisms to manipulate force transmission around the kinematic singularities. We developed a theoretical model to explore the parameter space for proper force transmission in slider-crank and rocker-crank four-bar kinematics. Finally, we verified the proposed model and methodology by building and testing a macro-scale prototype of a slider-crank mechanism. We expect this approach to enable the development of small-scale rotary engines and robotic devices with closed kinematic chains dealing with serial kinematic singularities, such as linkages and parallel manipulators.

This paper considers a combination of actuation tendons and measurement strings to achieve accurate shape sensing and direct kinematics of continuum robots. Assuming general string routing, a methodical Lie group formulation for the shape sensing of these robots is presented. The shape kinematics is expressed using arc-length-dependent curvature distributions parameterized by modal functions, and the Magnus expansion for Lie group integration is used to express the shape as a product of exponentials. The tendon and string length kinematic constraints are solved for the modal coefficients and the configuration space and body Jacobian are derived. The noise amplification index for the shape reconstruction problem is defined and used for optimizing the string/tendon routing paths, and a planar simulation study shows the minimal number of strings/tendons needed for accurate shape reconstruction. A torsionally stiff continuum segment is used for experimental evaluation, demonstrating mean (maximal) end-effector absolute position error of less than 2% (5%) of total length. Finally, a simulation study of a torsionally compliant segment demonstrates the approach for general deflections and string routings. We believe that the methods of this paper can benefit the design process, sensing and control of continuum and soft robots.