ݠन۞ (Machine Learning)
• “The field of study that gives computers the ability to learn
without being explicitly programmed.” - Arthur Samuel
• “A computer program is said to learn from experience E
with respect to some class of tasks T and performance
measure P, if its performance at tasks in T, as measured by
P, improves with experience E.” - Tom Mitchell
• : ߄قѱਸ فח ஹೊఠ
- E = ߄قѱਸ فח ҃
- T = ߄قѱਸ فח ೯ਤ
- P = ஹೊఠо ౸ ߄قਸ ӡ ഛܫ
Linear Regression
• y = a * x + b
- x: և(ಣ)
- y: оѺ
- h(x) ৬ э അೞӝب ೣ (hypothesis, оࢸ)
- ৬ э അ
• Training dataܳ learning algorithmী ਊ, h ܳ ҳೣ!
• h ܳ ਊೞৈ x ী ೠ Ѿҗч (y) ܳ ஏ оמ
Linear Regression Gradient Descent
• Bowl-shaped convex function
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Linear Regression Gradient Descent
• Iterationਸ ా೧ ୭ਸ ইх
(for fixed , this is a function of x) (function of the parameters )
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Linear Regression Gradient Descent
(for fixed , this is a function of x) (function of the parameters )
(for fixed , this is a function of x) (function of the parameters )
(for fixed , this is a function of x) (function of the parameters )
(for fixed , this is a function of x) (function of the parameters )
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Linear Regression Gradient Descent
(for fixed , this is a function of x) (function of the parameters )
(for fixed , this is a function of x) (function of the parameters )
(for fixed , this is a function of x) (function of the parameters )
(for fixed , this is a function of x) (function of the parameters )
Neural Network - Back Propagation
• Back propagation
Layer 1 Layer 2 Layer 3 Layer 4
Intuition: “error” of node in layer .
For each output unit (layer L = 4)