SlideShare a Scribd company logo
Machine Learning-1
Presented by Skillslash
What is MC Learning
www.skillslash.com
The subfield of computer science that “gives computers the ability to learn
without being explicitly programmed”.
(Arthur Samuel, 1959)
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, 1997)
Using data for answering
questions
High Bias and Low Variance
(Low Flexibility)
Low Bias and High Variance
(Too Flexibility)
Low Bias and High Variance
(Balanced Flexibility)
Bias Error:
The bias is known as the difference between the prediction of the values by the ML model and the correct
value. Being high in biasing gives a large error in training as well as testing data.
Variance Error:
Variance is the amount that the estimate of the target function will change if different training data was
used.
www.skillslash.com
Types of Machine Learning
Supervised Learning vs Unsupervised Learning
Un-Supervised Learning
Clustering
Regression vs Classification
Semi Supervised Learning
Types of Supervised ML
Supervise
d
Unsupervise
d
Reinforceme
nt
Output is a discrete variable
(e.g.,
Defaulter and Non Defaulter
Spam and non spam
Purchaser Non Purchaser)
Classificatio
n
Regressio
n
Output is continuous (e.g.,
price of house,
temperature)
www.skillslash.com
www.skillslash.com
Supervise
d
Unsupervise
d
Reinforceme
nt
www.skillslash.com
www.skillslash.com
Types of Machine Learning
Problems
Supervise
d
Unsupervise
d
Reinforceme
nt
Supervise
d
Is this a cat or a dog?
Are these emails spam or not?
Unsupervised
Predict the market value of houses, given the
square meters, number of rooms,
neighborhood, etc.
Reinforcement
Learn through examples of which we know
the desired output (what we want to
predict).
Types of Machine Learning
Problems
Unsupervise
d
Supervised
There is no desired output. Learn something
about the data. Latent relationships.
I want to find anomalies in the credit card
usage patterns of my customers.
Reinforcement
I have photos and want to put them in
20 groups.
www.skillslash.com
Types of Machine Learning
Problems
Unsupervise
d
Supervise
d
Reinforceme
nt
Useful for learning structure in the data
(clustering), hidden correlations, reduce
dimensionality, etc.
www.skillslash.com
Environment gives feedback via a
positive or negative reward signal.
Unsupervised
Reinforceme
nt
Supervise
d
An agent interacts with an environment and
watches the result of the interaction.
Types of Machine Learning
Problems
www.skillslash.com
Data Gathering
60
Might depend on human work
• Manual labeling for supervised learning.
• Domain knowledge. Maybe even experts.
May come for free, or “sort of”
• E.g., Machine Translation.
The more the better: Some algorithms need large amounts of data
to be useful (e.g., neural networks).
The quantity and quality of data dictate the model accuracy
www.skillslash.com
Data Preprocessing
61
Is there anything wrong with the data?
• Missing values
• Outliers
• Bad encoding (for text)
• Wrongly-labeled examples
• Biased data
• Do I have many more samples of one
class than the rest?
Need to fix/remove data?
www.skillslash.com
Feature Engineering
62
What is a feature?
A feature is an individual measurable
property of a phenomenon being
observed
Our inputs are represented by a set of
features.
To classify spam email, features could be:
• Number of words that have been
ch4ng3d
like this.
• Language of the email
Buy ch34p drugs
from the
ph4rm4cy now :)
:) :)
(2, 0, 3)
Feature
engineerin
g
www.skillslash.com
Feature Engineering
63
Extract more information from existing data, not adding “new” data
per-se
• Making it more useful
• With good features, most algorithms can learn
faster It can be an art
• Requires thought and knowledge of the
data Two steps:
• Variable transformation (e.g., dates into weekdays,
normalizing)
www.skillslash.com
Algorithm Selection & Training
64
Supervise
d
• Linear classifier
• Naive Bayes
• Support Vector Machines
(SVM)
• Decision Tree
• Random Forests
• k-Nearest Neighbors
• Neural Networks (Deep
learning)
Unsupervise
d
• PCA
• t-SNE
• k-mean
s
• DBSCAN
Reinforcemen
t
• SARSA–λ
• Q-Learnin
g
www.skillslash.com
65
THE MACHINE LEARNING FRAMEWORK
y = f(x)
● Training: given a training set of labeled examples {(x1
,y1
), …,
(xN
,yN
)}, estimate the prediction function f by minimizing the
prediction error on the training set
● Testing: apply f to a never before seen test example x and
output the predicted value y = f(x)
output prediction
function
Image
feature
www.skillslash.com
Goal of training: making the correct prediction as often as
possible
• Incremental improvement:
• Use of metrics for evaluating performance and comparing
solutions
• Hyperparameter tuning: more an art than a science
Algorithm Selection & Training
66
Predic
t
Adjus
t
www.skillslash.com
Summary
67
• Machine Learning is intelligent use of data to answer questions
• Enabled by an exponential increase in computing power and
data availability
• Three big types of problems: supervised, unsupervised,
reinforcement
• 5 steps to every machine learning solution:
1. Data Gathering
2. Data Preprocessing
3. Feature Engineering
4. Algorithm Selection & Training
5. Making Predictions www.skillslash.com
Generalization
● How well does a learned model generalize from the data it
was trained on to a new test set?
Training set (labels known) Test set (labels
unknown)
Generalization
● Components of generalization error
○ Bias: how much the average model over all training sets differ from the true
model?
■ Error due to inaccurate assumptions/simplifications made by the model
■ Using very less features
○ Variance: how much models estimated from different training sets differ from
each other
● Underfitting: model is too “simple” to represent all the relevant class
characteristics
○ High bias and low variance
○ High training error and high test error
● Overfitting: model is too “complex” and fits irrelevant characteristics
(noise) in the data
○ Low bias and high variance
○ Low training error and high test error
Bias-Variance Trade-off
• Models with too few parameters are
inaccurate because of a large bias (not
enough flexibility).
• Bias can also come due to wrong
assumption.
• Lead to Train error
• Models with too many parameters are
inaccurate because of a large variance
(too much sensitivity to the sample).
• Lead to Test Error
www.skillslash.com
THANK YOU
www.skillslash.com
Machine Learning - Lecture1.pptx.pdf
Machine Learning - Lecture1.pptx.pdf
Machine Learning - Lecture1.pptx.pdf
Machine Learning - Lecture1.pptx.pdf
Machine Learning - Lecture1.pptx.pdf
Machine Learning - Lecture1.pptx.pdf
Machine Learning - Lecture1.pptx.pdf
Machine Learning - Lecture1.pptx.pdf
Machine Learning - Lecture1.pptx.pdf
Machine Learning - Lecture1.pptx.pdf
Machine Learning - Lecture1.pptx.pdf
Machine Learning - Lecture1.pptx.pdf
Machine Learning - Lecture1.pptx.pdf
Machine Learning - Lecture1.pptx.pdf
Machine Learning - Lecture1.pptx.pdf
Machine Learning - Lecture1.pptx.pdf
Machine Learning - Lecture1.pptx.pdf
Machine Learning - Lecture1.pptx.pdf

More Related Content

Similar to Machine Learning - Lecture1.pptx.pdf

Introduction to Machine Learning.pptx
Introduction to Machine Learning.pptxIntroduction to Machine Learning.pptx
Introduction to Machine Learning.pptx
Dr. Amanpreet Kaur
 
Introduction to ML (Machine Learning)
Introduction to ML (Machine Learning)Introduction to ML (Machine Learning)
Introduction to ML (Machine Learning)
SwatiTripathi44
 
introduction to machine learning
introduction to machine learningintroduction to machine learning
introduction to machine learning
Johnson Ubah
 
Supervised learning techniques and applications
Supervised learning techniques and applicationsSupervised learning techniques and applications
Supervised learning techniques and applications
Benjaminlapid1
 
Machine Learning by Rj
Machine Learning by RjMachine Learning by Rj
ML basics.pptx
ML basics.pptxML basics.pptx
ML basics.pptx
PriyadharshiniG41
 
MachineLearning_AishwaryaCR
MachineLearning_AishwaryaCRMachineLearning_AishwaryaCR
MachineLearning_AishwaryaCR
Aishwarya C Ramachandran
 
Optimal Model Complexity (1).pptx
Optimal Model Complexity (1).pptxOptimal Model Complexity (1).pptx
Optimal Model Complexity (1).pptx
MurindanyiSudi1
 
Machine learning with ADA Boost
Machine learning with ADA BoostMachine learning with ADA Boost
Machine learning with ADA Boost
Aman Patel
 
Machine Learning course in Chandigarh Join
Machine Learning course in Chandigarh JoinMachine Learning course in Chandigarh Join
Machine Learning course in Chandigarh Join
asmeerana605
 
Tech meetup Data Driven - Codemotion
Tech meetup Data Driven - Codemotion Tech meetup Data Driven - Codemotion
Tech meetup Data Driven - Codemotion
antimo musone
 
It's Machine Learning Basics -- For You!
It's Machine Learning Basics -- For You!It's Machine Learning Basics -- For You!
It's Machine Learning Basics -- For You!
To Sum It Up
 
Introduction to machine learning-2023-IT-AI and DS.pdf
Introduction to machine learning-2023-IT-AI and DS.pdfIntroduction to machine learning-2023-IT-AI and DS.pdf
Introduction to machine learning-2023-IT-AI and DS.pdf
SisayNegash4
 
Machine Learning Chapter one introduction
Machine Learning Chapter one introductionMachine Learning Chapter one introduction
Machine Learning Chapter one introduction
ARVIND SARDAR
 
Intro to machine learning
Intro to machine learningIntro to machine learning
Intro to machine learning
Akshay Kanchan
 
Machine Learning - Deep Learning
Machine Learning - Deep LearningMachine Learning - Deep Learning
Machine Learning - Deep Learning
Adetimehin Oluwasegun Matthew
 
Machine Learning 2 deep Learning: An Intro
Machine Learning 2 deep Learning: An IntroMachine Learning 2 deep Learning: An Intro
Machine Learning 2 deep Learning: An Intro
Si Krishan
 
Rahul_Kirtoniya_11800121032_CSE_Machine_Learning.pptx
Rahul_Kirtoniya_11800121032_CSE_Machine_Learning.pptxRahul_Kirtoniya_11800121032_CSE_Machine_Learning.pptx
Rahul_Kirtoniya_11800121032_CSE_Machine_Learning.pptx
RahulKirtoniya
 
Machine Learning Interview Questions
Machine Learning Interview QuestionsMachine Learning Interview Questions
Machine Learning Interview Questions
Rock Interview
 
Unit-1.ppt
Unit-1.pptUnit-1.ppt
Unit-1.ppt
ASrinivasReddy3
 

Similar to Machine Learning - Lecture1.pptx.pdf (20)

Introduction to Machine Learning.pptx
Introduction to Machine Learning.pptxIntroduction to Machine Learning.pptx
Introduction to Machine Learning.pptx
 
Introduction to ML (Machine Learning)
Introduction to ML (Machine Learning)Introduction to ML (Machine Learning)
Introduction to ML (Machine Learning)
 
introduction to machine learning
introduction to machine learningintroduction to machine learning
introduction to machine learning
 
Supervised learning techniques and applications
Supervised learning techniques and applicationsSupervised learning techniques and applications
Supervised learning techniques and applications
 
Machine Learning by Rj
Machine Learning by RjMachine Learning by Rj
Machine Learning by Rj
 
ML basics.pptx
ML basics.pptxML basics.pptx
ML basics.pptx
 
MachineLearning_AishwaryaCR
MachineLearning_AishwaryaCRMachineLearning_AishwaryaCR
MachineLearning_AishwaryaCR
 
Optimal Model Complexity (1).pptx
Optimal Model Complexity (1).pptxOptimal Model Complexity (1).pptx
Optimal Model Complexity (1).pptx
 
Machine learning with ADA Boost
Machine learning with ADA BoostMachine learning with ADA Boost
Machine learning with ADA Boost
 
Machine Learning course in Chandigarh Join
Machine Learning course in Chandigarh JoinMachine Learning course in Chandigarh Join
Machine Learning course in Chandigarh Join
 
Tech meetup Data Driven - Codemotion
Tech meetup Data Driven - Codemotion Tech meetup Data Driven - Codemotion
Tech meetup Data Driven - Codemotion
 
It's Machine Learning Basics -- For You!
It's Machine Learning Basics -- For You!It's Machine Learning Basics -- For You!
It's Machine Learning Basics -- For You!
 
Introduction to machine learning-2023-IT-AI and DS.pdf
Introduction to machine learning-2023-IT-AI and DS.pdfIntroduction to machine learning-2023-IT-AI and DS.pdf
Introduction to machine learning-2023-IT-AI and DS.pdf
 
Machine Learning Chapter one introduction
Machine Learning Chapter one introductionMachine Learning Chapter one introduction
Machine Learning Chapter one introduction
 
Intro to machine learning
Intro to machine learningIntro to machine learning
Intro to machine learning
 
Machine Learning - Deep Learning
Machine Learning - Deep LearningMachine Learning - Deep Learning
Machine Learning - Deep Learning
 
Machine Learning 2 deep Learning: An Intro
Machine Learning 2 deep Learning: An IntroMachine Learning 2 deep Learning: An Intro
Machine Learning 2 deep Learning: An Intro
 
Rahul_Kirtoniya_11800121032_CSE_Machine_Learning.pptx
Rahul_Kirtoniya_11800121032_CSE_Machine_Learning.pptxRahul_Kirtoniya_11800121032_CSE_Machine_Learning.pptx
Rahul_Kirtoniya_11800121032_CSE_Machine_Learning.pptx
 
Machine Learning Interview Questions
Machine Learning Interview QuestionsMachine Learning Interview Questions
Machine Learning Interview Questions
 
Unit-1.ppt
Unit-1.pptUnit-1.ppt
Unit-1.ppt
 

Recently uploaded

一比一原版(UofM毕业证)明尼苏达大学毕业证成绩单
一比一原版(UofM毕业证)明尼苏达大学毕业证成绩单一比一原版(UofM毕业证)明尼苏达大学毕业证成绩单
一比一原版(UofM毕业证)明尼苏达大学毕业证成绩单
ewymefz
 
做(mqu毕业证书)麦考瑞大学毕业证硕士文凭证书学费发票原版一模一样
做(mqu毕业证书)麦考瑞大学毕业证硕士文凭证书学费发票原版一模一样做(mqu毕业证书)麦考瑞大学毕业证硕士文凭证书学费发票原版一模一样
做(mqu毕业证书)麦考瑞大学毕业证硕士文凭证书学费发票原版一模一样
axoqas
 
社内勉強会資料_LLM Agents                              .
社内勉強会資料_LLM Agents                              .社内勉強会資料_LLM Agents                              .
社内勉強会資料_LLM Agents                              .
NABLAS株式会社
 
Best best suvichar in gujarati english meaning of this sentence as Silk road ...
Best best suvichar in gujarati english meaning of this sentence as Silk road ...Best best suvichar in gujarati english meaning of this sentence as Silk road ...
Best best suvichar in gujarati english meaning of this sentence as Silk road ...
AbhimanyuSinha9
 
Criminal IP - Threat Hunting Webinar.pdf
Criminal IP - Threat Hunting Webinar.pdfCriminal IP - Threat Hunting Webinar.pdf
Criminal IP - Threat Hunting Webinar.pdf
Criminal IP
 
一比一原版(CU毕业证)卡尔顿大学毕业证成绩单
一比一原版(CU毕业证)卡尔顿大学毕业证成绩单一比一原版(CU毕业证)卡尔顿大学毕业证成绩单
一比一原版(CU毕业证)卡尔顿大学毕业证成绩单
yhkoc
 
一比一原版(UVic毕业证)维多利亚大学毕业证成绩单
一比一原版(UVic毕业证)维多利亚大学毕业证成绩单一比一原版(UVic毕业证)维多利亚大学毕业证成绩单
一比一原版(UVic毕业证)维多利亚大学毕业证成绩单
ukgaet
 
Empowering Data Analytics Ecosystem.pptx
Empowering Data Analytics Ecosystem.pptxEmpowering Data Analytics Ecosystem.pptx
Empowering Data Analytics Ecosystem.pptx
benishzehra469
 
一比一原版(RUG毕业证)格罗宁根大学毕业证成绩单
一比一原版(RUG毕业证)格罗宁根大学毕业证成绩单一比一原版(RUG毕业证)格罗宁根大学毕业证成绩单
一比一原版(RUG毕业证)格罗宁根大学毕业证成绩单
vcaxypu
 
Criminal IP - Threat Hunting Webinar.pdf
Criminal IP - Threat Hunting Webinar.pdfCriminal IP - Threat Hunting Webinar.pdf
Criminal IP - Threat Hunting Webinar.pdf
Criminal IP
 
原版制作(Deakin毕业证书)迪肯大学毕业证学位证一模一样
原版制作(Deakin毕业证书)迪肯大学毕业证学位证一模一样原版制作(Deakin毕业证书)迪肯大学毕业证学位证一模一样
原版制作(Deakin毕业证书)迪肯大学毕业证学位证一模一样
u86oixdj
 
一比一原版(UniSA毕业证书)南澳大学毕业证如何办理
一比一原版(UniSA毕业证书)南澳大学毕业证如何办理一比一原版(UniSA毕业证书)南澳大学毕业证如何办理
一比一原版(UniSA毕业证书)南澳大学毕业证如何办理
slg6lamcq
 
一比一原版(NYU毕业证)纽约大学毕业证成绩单
一比一原版(NYU毕业证)纽约大学毕业证成绩单一比一原版(NYU毕业证)纽约大学毕业证成绩单
一比一原版(NYU毕业证)纽约大学毕业证成绩单
ewymefz
 
一比一原版(Bradford毕业证书)布拉德福德大学毕业证如何办理
一比一原版(Bradford毕业证书)布拉德福德大学毕业证如何办理一比一原版(Bradford毕业证书)布拉德福德大学毕业证如何办理
一比一原版(Bradford毕业证书)布拉德福德大学毕业证如何办理
mbawufebxi
 
Chatty Kathy - UNC Bootcamp Final Project Presentation - Final Version - 5.23...
Chatty Kathy - UNC Bootcamp Final Project Presentation - Final Version - 5.23...Chatty Kathy - UNC Bootcamp Final Project Presentation - Final Version - 5.23...
Chatty Kathy - UNC Bootcamp Final Project Presentation - Final Version - 5.23...
John Andrews
 
一比一原版(CBU毕业证)卡普顿大学毕业证如何办理
一比一原版(CBU毕业证)卡普顿大学毕业证如何办理一比一原版(CBU毕业证)卡普顿大学毕业证如何办理
一比一原版(CBU毕业证)卡普顿大学毕业证如何办理
ahzuo
 
一比一原版(TWU毕业证)西三一大学毕业证成绩单
一比一原版(TWU毕业证)西三一大学毕业证成绩单一比一原版(TWU毕业证)西三一大学毕业证成绩单
一比一原版(TWU毕业证)西三一大学毕业证成绩单
ocavb
 
一比一原版(CBU毕业证)卡普顿大学毕业证成绩单
一比一原版(CBU毕业证)卡普顿大学毕业证成绩单一比一原版(CBU毕业证)卡普顿大学毕业证成绩单
一比一原版(CBU毕业证)卡普顿大学毕业证成绩单
nscud
 
一比一原版(ArtEZ毕业证)ArtEZ艺术学院毕业证成绩单
一比一原版(ArtEZ毕业证)ArtEZ艺术学院毕业证成绩单一比一原版(ArtEZ毕业证)ArtEZ艺术学院毕业证成绩单
一比一原版(ArtEZ毕业证)ArtEZ艺术学院毕业证成绩单
vcaxypu
 
Sample_Global Non-invasive Prenatal Testing (NIPT) Market, 2019-2030.pdf
Sample_Global Non-invasive Prenatal Testing (NIPT) Market, 2019-2030.pdfSample_Global Non-invasive Prenatal Testing (NIPT) Market, 2019-2030.pdf
Sample_Global Non-invasive Prenatal Testing (NIPT) Market, 2019-2030.pdf
Linda486226
 

Recently uploaded (20)

一比一原版(UofM毕业证)明尼苏达大学毕业证成绩单
一比一原版(UofM毕业证)明尼苏达大学毕业证成绩单一比一原版(UofM毕业证)明尼苏达大学毕业证成绩单
一比一原版(UofM毕业证)明尼苏达大学毕业证成绩单
 
做(mqu毕业证书)麦考瑞大学毕业证硕士文凭证书学费发票原版一模一样
做(mqu毕业证书)麦考瑞大学毕业证硕士文凭证书学费发票原版一模一样做(mqu毕业证书)麦考瑞大学毕业证硕士文凭证书学费发票原版一模一样
做(mqu毕业证书)麦考瑞大学毕业证硕士文凭证书学费发票原版一模一样
 
社内勉強会資料_LLM Agents                              .
社内勉強会資料_LLM Agents                              .社内勉強会資料_LLM Agents                              .
社内勉強会資料_LLM Agents                              .
 
Best best suvichar in gujarati english meaning of this sentence as Silk road ...
Best best suvichar in gujarati english meaning of this sentence as Silk road ...Best best suvichar in gujarati english meaning of this sentence as Silk road ...
Best best suvichar in gujarati english meaning of this sentence as Silk road ...
 
Criminal IP - Threat Hunting Webinar.pdf
Criminal IP - Threat Hunting Webinar.pdfCriminal IP - Threat Hunting Webinar.pdf
Criminal IP - Threat Hunting Webinar.pdf
 
一比一原版(CU毕业证)卡尔顿大学毕业证成绩单
一比一原版(CU毕业证)卡尔顿大学毕业证成绩单一比一原版(CU毕业证)卡尔顿大学毕业证成绩单
一比一原版(CU毕业证)卡尔顿大学毕业证成绩单
 
一比一原版(UVic毕业证)维多利亚大学毕业证成绩单
一比一原版(UVic毕业证)维多利亚大学毕业证成绩单一比一原版(UVic毕业证)维多利亚大学毕业证成绩单
一比一原版(UVic毕业证)维多利亚大学毕业证成绩单
 
Empowering Data Analytics Ecosystem.pptx
Empowering Data Analytics Ecosystem.pptxEmpowering Data Analytics Ecosystem.pptx
Empowering Data Analytics Ecosystem.pptx
 
一比一原版(RUG毕业证)格罗宁根大学毕业证成绩单
一比一原版(RUG毕业证)格罗宁根大学毕业证成绩单一比一原版(RUG毕业证)格罗宁根大学毕业证成绩单
一比一原版(RUG毕业证)格罗宁根大学毕业证成绩单
 
Criminal IP - Threat Hunting Webinar.pdf
Criminal IP - Threat Hunting Webinar.pdfCriminal IP - Threat Hunting Webinar.pdf
Criminal IP - Threat Hunting Webinar.pdf
 
原版制作(Deakin毕业证书)迪肯大学毕业证学位证一模一样
原版制作(Deakin毕业证书)迪肯大学毕业证学位证一模一样原版制作(Deakin毕业证书)迪肯大学毕业证学位证一模一样
原版制作(Deakin毕业证书)迪肯大学毕业证学位证一模一样
 
一比一原版(UniSA毕业证书)南澳大学毕业证如何办理
一比一原版(UniSA毕业证书)南澳大学毕业证如何办理一比一原版(UniSA毕业证书)南澳大学毕业证如何办理
一比一原版(UniSA毕业证书)南澳大学毕业证如何办理
 
一比一原版(NYU毕业证)纽约大学毕业证成绩单
一比一原版(NYU毕业证)纽约大学毕业证成绩单一比一原版(NYU毕业证)纽约大学毕业证成绩单
一比一原版(NYU毕业证)纽约大学毕业证成绩单
 
一比一原版(Bradford毕业证书)布拉德福德大学毕业证如何办理
一比一原版(Bradford毕业证书)布拉德福德大学毕业证如何办理一比一原版(Bradford毕业证书)布拉德福德大学毕业证如何办理
一比一原版(Bradford毕业证书)布拉德福德大学毕业证如何办理
 
Chatty Kathy - UNC Bootcamp Final Project Presentation - Final Version - 5.23...
Chatty Kathy - UNC Bootcamp Final Project Presentation - Final Version - 5.23...Chatty Kathy - UNC Bootcamp Final Project Presentation - Final Version - 5.23...
Chatty Kathy - UNC Bootcamp Final Project Presentation - Final Version - 5.23...
 
一比一原版(CBU毕业证)卡普顿大学毕业证如何办理
一比一原版(CBU毕业证)卡普顿大学毕业证如何办理一比一原版(CBU毕业证)卡普顿大学毕业证如何办理
一比一原版(CBU毕业证)卡普顿大学毕业证如何办理
 
一比一原版(TWU毕业证)西三一大学毕业证成绩单
一比一原版(TWU毕业证)西三一大学毕业证成绩单一比一原版(TWU毕业证)西三一大学毕业证成绩单
一比一原版(TWU毕业证)西三一大学毕业证成绩单
 
一比一原版(CBU毕业证)卡普顿大学毕业证成绩单
一比一原版(CBU毕业证)卡普顿大学毕业证成绩单一比一原版(CBU毕业证)卡普顿大学毕业证成绩单
一比一原版(CBU毕业证)卡普顿大学毕业证成绩单
 
一比一原版(ArtEZ毕业证)ArtEZ艺术学院毕业证成绩单
一比一原版(ArtEZ毕业证)ArtEZ艺术学院毕业证成绩单一比一原版(ArtEZ毕业证)ArtEZ艺术学院毕业证成绩单
一比一原版(ArtEZ毕业证)ArtEZ艺术学院毕业证成绩单
 
Sample_Global Non-invasive Prenatal Testing (NIPT) Market, 2019-2030.pdf
Sample_Global Non-invasive Prenatal Testing (NIPT) Market, 2019-2030.pdfSample_Global Non-invasive Prenatal Testing (NIPT) Market, 2019-2030.pdf
Sample_Global Non-invasive Prenatal Testing (NIPT) Market, 2019-2030.pdf
 

Machine Learning - Lecture1.pptx.pdf

  • 2. What is MC Learning www.skillslash.com The subfield of computer science that “gives computers the ability to learn without being explicitly programmed”. (Arthur Samuel, 1959) 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, 1997) Using data for answering questions
  • 3.
  • 4.
  • 5.
  • 6.
  • 7.
  • 8.
  • 9.
  • 10.
  • 11.
  • 12.
  • 13.
  • 14.
  • 15.
  • 16.
  • 17.
  • 18.
  • 19.
  • 20.
  • 21.
  • 22.
  • 23.
  • 24.
  • 25.
  • 26.
  • 27.
  • 28.
  • 29.
  • 30.
  • 31.
  • 32.
  • 33.
  • 34.
  • 35.
  • 36.
  • 37.
  • 38.
  • 39.
  • 40. High Bias and Low Variance (Low Flexibility) Low Bias and High Variance (Too Flexibility) Low Bias and High Variance (Balanced Flexibility)
  • 41. Bias Error: The bias is known as the difference between the prediction of the values by the ML model and the correct value. Being high in biasing gives a large error in training as well as testing data. Variance Error: Variance is the amount that the estimate of the target function will change if different training data was used.
  • 43. Supervised Learning vs Unsupervised Learning
  • 44.
  • 45.
  • 50. Types of Supervised ML Supervise d Unsupervise d Reinforceme nt Output is a discrete variable (e.g., Defaulter and Non Defaulter Spam and non spam Purchaser Non Purchaser) Classificatio n Regressio n Output is continuous (e.g., price of house, temperature) www.skillslash.com
  • 52.
  • 55. Types of Machine Learning Problems Supervise d Unsupervise d Reinforceme nt Supervise d Is this a cat or a dog? Are these emails spam or not? Unsupervised Predict the market value of houses, given the square meters, number of rooms, neighborhood, etc. Reinforcement Learn through examples of which we know the desired output (what we want to predict).
  • 56. Types of Machine Learning Problems Unsupervise d Supervised There is no desired output. Learn something about the data. Latent relationships. I want to find anomalies in the credit card usage patterns of my customers. Reinforcement I have photos and want to put them in 20 groups. www.skillslash.com
  • 57. Types of Machine Learning Problems Unsupervise d Supervise d Reinforceme nt Useful for learning structure in the data (clustering), hidden correlations, reduce dimensionality, etc. www.skillslash.com
  • 58. Environment gives feedback via a positive or negative reward signal. Unsupervised Reinforceme nt Supervise d An agent interacts with an environment and watches the result of the interaction. Types of Machine Learning Problems www.skillslash.com
  • 59.
  • 60. Data Gathering 60 Might depend on human work • Manual labeling for supervised learning. • Domain knowledge. Maybe even experts. May come for free, or “sort of” • E.g., Machine Translation. The more the better: Some algorithms need large amounts of data to be useful (e.g., neural networks). The quantity and quality of data dictate the model accuracy www.skillslash.com
  • 61. Data Preprocessing 61 Is there anything wrong with the data? • Missing values • Outliers • Bad encoding (for text) • Wrongly-labeled examples • Biased data • Do I have many more samples of one class than the rest? Need to fix/remove data? www.skillslash.com
  • 62. Feature Engineering 62 What is a feature? A feature is an individual measurable property of a phenomenon being observed Our inputs are represented by a set of features. To classify spam email, features could be: • Number of words that have been ch4ng3d like this. • Language of the email Buy ch34p drugs from the ph4rm4cy now :) :) :) (2, 0, 3) Feature engineerin g www.skillslash.com
  • 63. Feature Engineering 63 Extract more information from existing data, not adding “new” data per-se • Making it more useful • With good features, most algorithms can learn faster It can be an art • Requires thought and knowledge of the data Two steps: • Variable transformation (e.g., dates into weekdays, normalizing) www.skillslash.com
  • 64. Algorithm Selection & Training 64 Supervise d • Linear classifier • Naive Bayes • Support Vector Machines (SVM) • Decision Tree • Random Forests • k-Nearest Neighbors • Neural Networks (Deep learning) Unsupervise d • PCA • t-SNE • k-mean s • DBSCAN Reinforcemen t • SARSA–λ • Q-Learnin g www.skillslash.com
  • 65. 65 THE MACHINE LEARNING FRAMEWORK y = f(x) ● Training: given a training set of labeled examples {(x1 ,y1 ), …, (xN ,yN )}, estimate the prediction function f by minimizing the prediction error on the training set ● Testing: apply f to a never before seen test example x and output the predicted value y = f(x) output prediction function Image feature www.skillslash.com
  • 66. Goal of training: making the correct prediction as often as possible • Incremental improvement: • Use of metrics for evaluating performance and comparing solutions • Hyperparameter tuning: more an art than a science Algorithm Selection & Training 66 Predic t Adjus t www.skillslash.com
  • 67. Summary 67 • Machine Learning is intelligent use of data to answer questions • Enabled by an exponential increase in computing power and data availability • Three big types of problems: supervised, unsupervised, reinforcement • 5 steps to every machine learning solution: 1. Data Gathering 2. Data Preprocessing 3. Feature Engineering 4. Algorithm Selection & Training 5. Making Predictions www.skillslash.com
  • 68. Generalization ● How well does a learned model generalize from the data it was trained on to a new test set? Training set (labels known) Test set (labels unknown)
  • 69. Generalization ● Components of generalization error ○ Bias: how much the average model over all training sets differ from the true model? ■ Error due to inaccurate assumptions/simplifications made by the model ■ Using very less features ○ Variance: how much models estimated from different training sets differ from each other ● Underfitting: model is too “simple” to represent all the relevant class characteristics ○ High bias and low variance ○ High training error and high test error ● Overfitting: model is too “complex” and fits irrelevant characteristics (noise) in the data ○ Low bias and high variance ○ Low training error and high test error
  • 70.
  • 71.
  • 72. Bias-Variance Trade-off • Models with too few parameters are inaccurate because of a large bias (not enough flexibility). • Bias can also come due to wrong assumption. • Lead to Train error • Models with too many parameters are inaccurate because of a large variance (too much sensitivity to the sample). • Lead to Test Error