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Survival Tree01:19

Survival Tree

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Survival trees are a non-parametric method used in survival analysis to model the relationship between a set of covariates and the time until an event of interest occurs, often referred to as the "time-to-event" or "survival time." This method is particularly useful when dealing with censored data, where the event has not occurred for some individuals by the end of the study period, or when the exact time of the event is unknown.
 Building a Survival Tree
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Phylogenetic Trees03:21

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Phylogenetic trees come in many forms. It matters in which sequence the organisms are arranged from the bottom to the top of the tree, but the branches can rotate at their nodes without altering the information. The lines connecting individual nodes can be straight, angled, or even curved.
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Light Acquisition02:16

Light Acquisition

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In order to produce glucose, plants need to capture sufficient light energy. Many modern plants have evolved leaves specialized for light acquisition. Leaves can be only millimeters in width or tens of meters wide, depending on the environment. Due to competition for sunlight, evolution has driven the evolution of increasingly larger leaves and taller plants, to avoid shading by their neighbors with contaminant elaboration of root architecture and mechanisms to transport water and nutrients.
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Reducing Line Loss01:18

Reducing Line Loss

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In a three-phase circuit, line loss is an indicator of energy dissipated as heat due to the resistance of transmission lines. To address this, incorporating transformers into the system—a step-up transformer at the source and a step-down transformer at the load—is a strategic solution. Two three-phase transformers are introduced to improve this.
With a step-up transformer at the source, the voltage is increased, thereby reducing the current in the transmission lines since power loss...
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Accuracy, limits, and approximation01:28

Accuracy, limits, and approximation

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Accuracy, limits, and approximations are common in many fields, especially in engineering calculations. These concepts are imperative for ensuring that a given value is as close as possible to its true value.
Accuracy is defined as the closeness of the measured value to the true or actual value. In engineering mechanics, repeated measurements are taken during theoretical or experimental analyses to ensure that the result is precise and accurate.
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Basic Plant Anatomy: Roots, Stems, and Leaves02:27

Basic Plant Anatomy: Roots, Stems, and Leaves

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The primary organs of vascular plants are roots, stems, and leaves, but these structures can be highly variable, adapted for the specific needs and environment of different plant species.
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相关实验视频

Updated: Jun 17, 2025

Modeling the Functional Network for Spatial Navigation in the Human Brain
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Modeling the Functional Network for Spatial Navigation in the Human Brain

Published on: October 13, 2023

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更好的比-近似的树叶到树叶和连接增强增强.

Federica Cecchetto1, Vera Traub2, Rico Zenklusen1

  • 1Department of Mathematics, ETH Zurich, Zurich, Switzerland.

Mathematical programming
|August 12, 2024
PubMed
概括
此摘要是机器生成的。

我们为网络设计问题开发了一种简单的基于匹配的方法,特别是叶子对叶子连接增强问题 (CAP). 这种新方法实现了更好的近似系数,改进了CAP和TAP实例的现有技术.

关键词:
接近算法的近似算法组合优化的优化.连接增强 连接增强树的增强 树的增强

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LeafJ: An ImageJ Plugin for Semi-automated Leaf Shape Measurement
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LeafJ: An ImageJ Plugin for Semi-automated Leaf Shape Measurement

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Leaf Area Index Estimation Using Three Distinct Methods in Pure Deciduous Stands
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Leaf Area Index Estimation Using Three Distinct Methods in Pure Deciduous Stands

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相关实验视频

Last Updated: Jun 17, 2025

Modeling the Functional Network for Spatial Navigation in the Human Brain
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Modeling the Functional Network for Spatial Navigation in the Human Brain

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LeafJ: An ImageJ Plugin for Semi-automated Leaf Shape Measurement
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LeafJ: An ImageJ Plugin for Semi-automated Leaf Shape Measurement

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Leaf Area Index Estimation Using Three Distinct Methods in Pure Deciduous Stands
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Leaf Area Index Estimation Using Three Distinct Methods in Pure Deciduous Stands

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科学领域:

  • 计算机科学 计算机科学
  • 运营研究 运营研究
  • 算法设计 算法设计

背景情况:

  • 连接增大问题 (CAP) 和树增大问题 (TAP) 是网络设计的基本挑战.
  • 最近的研究重点是以低于2的因子进行近似算法,目前的最佳值为1.393.

研究的目的:

  • 介绍一种新的,简单的基于匹配的方法,用于CAP的叶子对叶子实例.
  • 改善特定的CAP和TAP问题类别的近似系数.

主要方法:

  • 一个新的基于匹配的算法,用于叶到叶的CAP实例.
  • 将新方法与现有技术和堆分析方法相结合.

主要成果:

  • 通过选择新解决方案和现有解决方案中更好的方法,实现了Leaf-to-Leaf CAP的近似.
  • 将TAP/CAP实例的非微不足道类的近似系数提高到1.29,超过了的值.

结论:

  • 新的基于匹配的方法为CAP和TAP提供了更简单的方法.
  • 改进的近似系数为1.29,代表了针对特定网络设计问题的重大进展.