L6 Flashcards

(37 cards)

1
Q

What are Parameters in the context of machine learning?

A

Values learned during training

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2
Q

What are Hyperparameters?

A

Set before training (like learning rate, number of neighbors, or regularization parameter C)

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3
Q

What is a Decision function?

A

Takes a dataset as input and gives a decision as output

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4
Q

What is the Loss function?

A

What you are trying to minimize for a single training example to achieve your objective (e.g. square loss)

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5
Q

What is a Cost function?

A

Average of your loss functions over the entire training set (e.g. mean square error)

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6
Q

What is a Training set used for?

A

Learn model parameters

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7
Q

What is a Validation set used for?

A

Tune hyperparameters

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8
Q

What is a Test set used for?

A

Evaluate final model performance

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9
Q

Why do we need SVMs?

A

To find the best line (or hyperplane) possible with the largest margin between classes

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10
Q

What does SVM stand for?

A

Support Vector Machine

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11
Q

What is the main goal of SVM in classification?

A

To separate classes with the widest possible gap or margin

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12
Q

What is the Margin in SVM?

A

The distance between the decision boundary and the closest data points (support vectors)

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13
Q

What are Support Vectors?

A

The data points closest to the boundary that define the position of the decision boundary

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14
Q

What is a Hard Margin SVM?

A

No errors allowed – aims to find a hyperplane that perfectly separates the classes without any misclassification

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15
Q

What is a Soft Margin SVM?

A

Allows some misclassification or overlap and measures how much an instance is allowed to violate the margin

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16
Q

What does hyperparameter C control in Soft Margin SVM?

A

Trade-off between margin size and classification errors

17
Q

True or False: A large C in SVM means more tolerance to errors.

18
Q

What is the decision function for a new data point in SVM?

A

If result ≥ 1 → positive class; If ≤ -1 → negative class; If in between → uncertain zone (margin)

19
Q

What type of problems do SVMs solve?

A

Convex quadratic optimization problems with linear constraints

20
Q

What is the kernel trick in SVM?

A

Projects data into a higher-dimensional space where it becomes linearly separable

21
Q

What is a Linear kernel used for?

A

Fast, simple, when data is already separable

22
Q

What does the RBF kernel offer?

A

Very flexible, works on complex data

23
Q

What is the purpose of the Gamma parameter in RBF kernels?

A

Controls how far a single point’s influence reaches

24
Q

What is One-vs-Rest (OvR) in multiclass classification?

A

One classifier per class vs all others

25
What is One-vs-One (OvO) in multiclass classification?
One classifier for every pair of classes
26
What is a One-Class SVM (OC-SVM) used for?
Learns from one class, useful for novelty or anomaly detection
27
What are the advantages of Linear SVMs?
Accuracy, works well on smaller cleaner datasets, can be more efficient
28
What are the disadvantages of Linear SVMs?
Not suited to larger datasets, less effective on noisier datasets
29
What is a key advantage of Kernel SVMs?
Allow for complex decision boundaries
30
What is a key disadvantage of Kernel SVMs?
Do not scale well with the number of samples
31
What is the role of preprocessing in SVMs?
Requires careful preprocessing of the data and tuning of the parameters
32
What is the meaning of Support Vectors in SVM?
Closest points to the margin
33
What does Margin refer to in SVM?
Distance between boundary and support vectors
34
What is a Hyperplane in SVM?
Decision boundary
35
What does parameter C control in SVM?
Trade-off between margin size and error
36
What is a Kernel in SVM?
Function that transforms data to higher dimensions
37
What does Gamma control in RBF kernels?
Influence of data points in RBF