【正文】 ct Page 47 Observation on How Human Brain Does Thinking ? Human beings often invoke latent variables to explain regularities that we observe. ? Example 1 ? Observe Regularity: ? Beers, Diapers often bought together in early evening ? Hypothesize (latent) cause: ? There must be a mon (latent) cause ? Identify the cause and explain regularity ? Shopping by Father of Babies on the way home from work ? Based on our understanding of the world Page 48 ? Example 2 ? Background: At night, watch lighting throw windows of apartments in big buildings ? Observe Regularity: ?Lighting from several apartments were changing in brightness and color at the same times and in perfect synchrony. ? Hypothesize mon (latent) cause: ?There must be a (late) mon cause ? Identify the cause and explain the phenomenon: ? People watching the same TV channel. ?Based on understanding of the world Observation on How Human Brain Does Thinking Page 49 Back to Ancient Time ? Observe Regularity ? Several symptoms often occur together ? ?intolerance to cold?, ?cold limbs?, and ?cold lumbus and back? ? Hypothesize mon latent cause: ? There must be a mon latent cause ? Identify the cause ? Answer based on understanding of world at that time, primitive ? Conclusion: Yang deficiency (陽虛 ) ? Explanation: Yang is like the sun, it warms your body. If you don?t have enough of it, feel cold. Page 50 Back to Ancient Time ? Regularity observed: ? Several symptoms often occur together ? Tidal fever (潮熱 )， heat sensation in palm and feet (手足心熱 ), palpitation (心慌心跳 ), thready and rapid pulse (脈細數(shù) ) ? Hypothesize mon latent cause: ? There must be a mon latent cause ? Identify the cause and explain the regularirt ? Yin deficiency causing internal heart (陰虛內(nèi)熱 ) ? Yin and Yang should be in balance. If Yin is in deficiency, Yang will be in excess relatively, and hence causes heat. Page 51 Traditional Chinese Medicine (TCM) ? Claim ? TCM Theories = Statistical Regularities + Subjective Interpretations ? How to justify the claim Page 52 A Case Study ? We collected a data set about kidney deficiency (腎虛 ) ? 35 symptom variables, 2600 records Page 53 Result of Data Analysis ? Y0Y34: manifest variables from data ? X0X13: latent variables introduced by data analysis ? Structure interesting, supports TCM?s theories about various symptoms. Page 54 Other TCM Data Sets ? From Beijing U of TCM, 973 project ? Depression ? Hepatitis B ? Chronic Renal Failure ? COPD ? Menopause ? China Academy of TCM ? Subhealth ? Diabetes ? In all cases, results of LT analysis match relevant TCM Theories Page 55 Result on the Depression Data Page 56 Significance ? Conclusion ? TCM Theories = Statistical Regularities + Subjective Interpretations ? Significance ? TCM theories are partially based on objective facts ?Boast user confidence ? Can help to lay a modern statistical foundation for TCM ?Systematically identify statistical regularities about occurrence of symptoms, find natural partitions ?Establish objective and quantitative diagnosis standards ?Assist in doubleblind experiments for evaluate and improve the efficacy of TCM treatment Page 57 Outline ? Traditional Uses ? Structure Discovery ? Density Estimation ? Classification ? Clustering ? An HKUST Project