The second difficulty is the basic idea of text to visualized scene is very simple but the concrete method and the step are undefined and the algorithm and the data structure of every step are undefined also . Every reasonable approach is possible .

其二在于从文字生成可视化场景在于基本的思想简单，但是具体的方法和步骤 不 固定，每一个文字到场景生成过程中的算法和 数据结构不明确，任何合理的做法都是可能的。

Artificial immune network clustering is often ineffective when there is noise or undefined cluster boundary in the data .

当 数据集聚类边界 不 清晰或存在噪声干扰时，人工免疫网络聚类算法通常无法获得有效的聚类划分。

Undefined factors during the prediction of oil and gas by seismic exploration include selection of seismic attributes selection of predicting algorithm environmental noises and surveying errors of raw data .

地震油气预测中的 不 确定性因素包括地震属性选取、预测算法选择、环境噪声及原始 数据观测误差等。