摘要：In order to improve the prediction precision of the safety performance function （SPF） of freeway basic segments, design and crash data of 640 segments are collected from different institutions. Three negative binomial （NB） regression models and three generalized negative binomial （GNB） regression models are built to prove that the interactive influence of explanatory variables plays an important role in fitting goodness. The effective use of the GNB model in analyzing the interactive influence of explanatory variables and predicting freeway basic segments is demonstrated. Among six models, the two models （one is the NB model and the other is the GNB model. ） which consider the interactive influence of the annual average daily traffic （AADT） and length are more reasonable for predicting results. Furthermore, a comprehensive study is carried out to prove that when considering the interactive influence, the NB and GNB models have almost the same fitting performance in estimating the crashes, among which the GNB model is slightly better for prediction performance.

摘要：摄影师、设计师、插画师、艺术家和数字画家都会用到Photoshop，但同时各有侧重。初学者常因为软件的功能强大望而却步。在接下来的文章中，我们带领大家处理一幅人像作品，然后进行抠图和背景更换，通过简明的操作和描述，来打消大家的恐惧感。

摘要：本文介绍了Linux crash Dump的设计与实现方法。Linux crash Dump提供了一种保存系统在发生crash时内存映象的能力。通过对Dump结果的分析,可以有效地帮助诊断系统出错的原因。本文介绍了如何进行crash Dump,以及Dump的数据的组织和保存方法等。

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