Yan Rongguo, Guo Xudong
School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, P.R. China.
Comput Methods Biomech Biomed Engin. 2013;16(6):660-8. doi: 10.1080/10255842.2011.631527. Epub 2012 Jan 31.
The computational fractal dimension of human colonic pressure activity acquired by a telemetric capsule robot under normal physiological conditions was studied using the box-counting method. The fractal dimension is a numeric value that quantifies to measure how rough the signal is from nonlinear dynamics, rather than its amplitude or other linear statistical features. The colonic pressure activities from the healthy subject during three typical periods were analysed. The results showed that the activity might be fractal with a non-integer fractal dimension after it being integrated over time using the cumsum method, which was never revealed before. Moreover, the activity (after it being integrated) acquired soon after wakening up was the roughest (also the most complex one) with the largest fractal dimension, closely followed by that acquired during sleep with that acquired long time after awakening up (in the daytime) ranking third with the smallest fractal dimension. Fractal estimation might provide a new method to learn the nonlinear dynamics of human gastrointestinal pressure recordings.
采用盒计数法研究了遥测胶囊机器人在正常生理条件下获取的人体结肠压力活动的计算分形维数。分形维数是一个数值，用于从非线性动力学角度量化测量信号的粗糙程度，而非其幅度或其他线性统计特征。分析了健康受试者在三个典型时期的结肠压力活动。结果表明，使用累积求和法对活动随时间积分后，其可能具有非整数分形维数的分形特征，这是此前从未揭示过的。此外，醒来后不久获取的活动（积分后）最粗糙（也是最复杂的），分形维数最大，其次是睡眠期间获取的活动，白天醒来很久后获取的活动分形维数最小，排名第三。分形估计可能为了解人体胃肠压力记录的非线性动力学提供一种新方法。
