Approximating the Normal Sample Median Distribution in Process Control

The present work aims to propose an approximation of the sample median distribution with a normal parent distribution. Although the mean is usually used as the central tendency measure for normal samples, the median has also been used in engineering, process control in particular. The proposed method approximates the normal sample median distribution only using the normal distribution function. It outperforms Castagliola’s method for small samples and serves as an alternative approximation for trading off accuracy against computational complexity for large samples.

Environmental Risk of Gas Hydrates Exploitation in Tibetan Plateau Permafrost

Gas hydrate samples were collected in Muli area (Qinghai Province, China) of Tibetan Plateau permafrost, which is the first discovery of gas hydrate in Chinese permafrost and in the low to middle latitude permafrost of the world. Although the exploitation of gas hydrate in Tibetan Plateau permafrost has lots of important significance, environmental risks including permafrost and alpine meadow ecosystem degeneration, global climate influence, and environmental pollution would take place in the exploitation process. In order to avoid or decrease the risk, safe and dependable exploitation technique, carbon capture and storage technology, engineering process control, legislation and emergency preparatory scheme should be put into practice.