Electric and electronic products are required to pass through the certification on electrical safety performance before entering into the market in order to reduce electrical shock and electrical fire so as to protect the safety of people and property. The leakage current is the most important factor in testing the electrical safety performance and the test theory is based on the perception current effect and threshold. The traditional method testing the current threshold for perception only depends on the sensing of the human body and is affected by psychological factors. Some authors filter the effect of subjective sensation by using physiological and psychological statistical algorithm in recent years and the reliability and consistency of the experiment data are improved. We established an experiment system of testing the human body's current threshold for perception based on EEG feature analysis, and obtained 967 groups of data. We used wavelet packet analysis to detect α wave from EEG, and used FFT to do spectral analysis on α wave before and after the current flew through the human body. The study has shown that about 97.72% α wave energy changes significantly when electrical stimulation occurs. It is well proved that when the EEG feature identification is applied to test the human body current threshold for perception, and meanwhile α wave energy change and human body sensing are used together to confirm if the current flowing through the human body reaches the perception threshold, the measurement of the human body current threshold for perception could be carried out objectively and accurately.
ObjectiveTo evaluate whether and to what extent the new risk of bias (ROB) tool has been used in Cochrane systematic reviews (CSRs) on acupuncture. MethodsWe searched the Cochrane Database of Systematic Review (CDSR) in issue 12, 2011. Two reviewers independently selected CSRs which primarily focused on acupuncture and moxibustion. Then the data involving in essential information, the information about ROB (sequence generation, allocation concealment, blindness, incomplete outcome data, selective reporting and other potential sources of bias) and GRADE were extracted and statistically analyzed. ResultsIn total, 41CSRs were identified, of which 19 CSRs were updated reviews. Thirty-three were published between 2009 and 2011. 60.98% reviews used the Cochrane Handbook as their ROB assessment tool. Most CSRs gave information about sequence generation, allocation concealment, blindness, and incomplete outcome data, however, half of them (54.55%, 8/69) showed selective reporting or other potential sources of bias. Conclusion"Risk of bias" tools have been used in most CSRs on acupuncture since 2009. However, the lack of evaluation items still remains.