【英文演讲】(运动的重要性)Importance of Sports

演讲者Jerry分享了运动的重要性,强调生命在于运动。他指出运动能缓解日常久坐带来的压力,提高大脑活力,改善睡眠质量,让生活更加多彩,并通过个人经历说明了运动对健康的具体益处。

Part One(mind mapping )

这里写图片描述

Part Two(speech content)

Opening remarks

Hello,Every body,I‘m jerry,I’m handsome and I’m cool. It’s my great honor to speak to you today, The title of my speech is the meaning of sports!

Benefit for sports

Life lies in movement. That said by one of China’s great man! it can be seen that sports is very very importment for us, for every body, every each people!Next, I’ll talk about the benefits of exercise! First,Every day we sat all day,Every single day we sat eight to ten hours at least,That make us tired and produce pressure! But sports can reduce our pressure,it can be relax our eys and brain,make our brain smart,If you keep exercising every day You’ll get smarter,more and more smart!

Second ,the sports is very importmant for our health,for our body! Every day , my neck and my back is very very sore! I can’t stand it ! So I decided to find a way to save my neck and back! that is Sports,I paid 900 yuan for a gym card,Three times a week,jason and me went to the gym ,and we train hard!in the end my back and neck did not sore!

Third,t Exercise has significantly improved my sleep quality! Whenever I finish exercising, I fall asleep very quickly in the night! and int the next morning,I’ll full of energy! and in the meanwhile,that make our life colorful!

How to love sports
On the one hand, If you don’t sleep well, you’re less study efficiency, you have neck and back pain, then you can try to exercise, and I sure that those negative things will go away~! and you will love it! One the other hand,you need a hobby aoout any sport,like basketball,football,pingpang,swim,fitness and so on! Let me give you an example,When I was in primary school, I played pingpang every day!and that make my eyes very good and I’m not nearsighted at all!

ending

Therefore, in order to have a good body, we should keep doing exercise !This is the end of my speech!Thank you all!

### SIMCA 模型中的变量重要性(Variable Importance) #### 背景介绍 SIMCA(Soft Independent Modeling of Class Analogy)是一种基于主成分分析(PCA)的分类方法,广泛应用于化学计量学领域。它通过对每类数据单独建立 PCA 模型来实现分类[^3]。在 SIMCA 中,变量的重要性可以通过多种方式评估,其中一种常用的方法是计算 **VIP 值**(Variable Importance in Projection),该指标能够反映每个变量对模型贡献的程度。 #### VIP 的定义与计算 VIP 是偏最小二乘法回归(PLS Regression)中常用的变量重要性度量之一,尽管其概念可以扩展到其他类型的建模技术。VIP 表示某个变量在整个 PLS 或类似模型中的全局重要性。具体而言: \[ \text{VIP}_j = \sqrt{\frac{t\sum_{a=1}^{A}\left(w_a^T R_y w_a\right)\left(v_jw_{aj}/s_a\right)}{\sum_{k=1}^{K}s_k}} \] 其中: - \( j \) 表示第 \( j \) 个变量; - \( A \) 表示潜变量的数量; - \( K \) 表示类别数量; - \( s_a \) 和 \( v_j \) 分别表示权重向量和得分矩阵的相关参数; 此公式用于衡量单个变量对整体模型性能的影响程度[^4]。 #### 变量重要性图的生成过程 为了生成 SIMCA 模型中的变量重要性图,以下是具体的流程描述: 1. 对于每一类数据分别构建独立的 PCA 模型。 2. 计算各变量在这些模型中的载荷值以及对应的方差解释率。 3. 利用上述 VIP 公式或其他相似算法综合评价各个变量的作用大小。 4. 将所得结果绘制成柱状图或者热力图形式展示出来以便直观理解哪些特征最为关键。 #### 解析注意事项 当观察到某些特定变量具有较高的 VIP 数值时,这表明它们可能是在区分不同组别间起到决定作用的关键因素。但是需要注意的是,仅仅依靠数值高低判断还不够全面,还需要结合专业知识背景进一步验证实际意义所在。 ```python import numpy as np from sklearn.cross_decomposition import PLSRegression def calculate_vip(model): t = model.x_scores_ w = model.x_weights_ q = model.y_loadings_ m, p = X.shape a = model.n_components vip = np.zeros((p,)) for i in range(a): weight = np.abs(q[i,:] * t[:,i].T @ t[:,i]) / np.linalg.norm(t[:,i])**2 vip += weight * sum(np.diag(model.y_loadings_.T @ model.coef_)) vip /= np.sqrt(m) return vip ``` 以上代码片段展示了如何利用 Python 实现基本的 VIP 计算逻辑。 #### 结论 综上所述,通过合理运用 VIP 方法可以帮助研究人员更好地理解和优化他们的 SIMCA 模型,并从中提取有价值的信息指导后续实验设计或决策制定工作。
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