Gatedocument, Thesis of Data Mining

gate - gate

Typology: Thesis

2014/2015

Uploaded on 12/01/2015

waseem.hussain1
waseem.hussain1 🇵🇰

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Machine Learning Spring 2015
Solution Assignment 01
Max Marks: 55
Theory Component
1 Hypothesis Spaces
1.1 Question 1 (10 points)
1. Consider the origin of the square is point (a, b) and the side-length of the square is s, then:
h(x) = (+1 (ax1a+s)AND(bx2b+s)
1otherwise (1)
2. There are three parameters, a, b, s.
3. O(N3). There are three parameters, each can vary between (1, N).
4. The most general hypothesis will be one with paramters: a= 0, b = 0, s =N. There are
multiple hypotheses which can be considered most specific, all with parameter s= 1,0
aN, 0bN.
5. An axis aligned rectangle hypothesis would require 4 parameters, a, b, l, w, where (a, b) is
the origin of rectangle and l, w are the length and width of the rectangle, respectively.
An axis-aligned square hypothesis space is a special case of axis-aligned rectangles with
l=w=s. Therefore, every hypothesis that can be represented by axis-aligned squares can
be represented by axis-aligned rectangles as well but the vice-versa is not true. Therefore,
axis-aligned rectangle hypothesis is richer than axis-aligned squares.
2 Similarity measures
2.1 Question 2 (2 points)
1. Edit distance
2. Hamming distance
3. Jaccard distance
4. Cosine distance
Last 3 require our non-numeric data to be encoded either as sets or using 1-of-m encoding.
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Machine Learning Spring 2015

Solution Assignment 01

Max Marks: 55

Theory Component

1 Hypothesis Spaces

1.1 Question 1 (10 points)

  1. Consider the origin of the square is point (a, b) and the side-length of the square is s, then:

h(x) =

+1 (a ≤ x 1 ≤ a + s)AN D(b ≤ x 2 ≤ b + s) − 1 otherwise

  1. There are three parameters, a, b, s.
  2. O(N 3 ). There are three parameters, each can vary between (1, N ).
  3. The most general hypothesis will be one with paramters: a = 0, b = 0, s = N. There are multiple hypotheses which can be considered most specific, all with parameter s = 1, 0 ≤ a ≤ N, 0 ≤ b ≤ N.
  4. An axis aligned rectangle hypothesis would require 4 parameters, a, b, l, w, where (a, b) is the origin of rectangle and l, w are the length and width of the rectangle, respectively. An axis-aligned square hypothesis space is a special case of axis-aligned rectangles with l = w = s. Therefore, every hypothesis that can be represented by axis-aligned squares can be represented by axis-aligned rectangles as well but the vice-versa is not true. Therefore, axis-aligned rectangle hypothesis is richer than axis-aligned squares.

2 Similarity measures

2.1 Question 2 (2 points)

  1. Edit distance
  2. Hamming distance
  3. Jaccard distance
  4. Cosine distance

Last 3 require our non-numeric data to be encoded either as sets or using 1-of-m encoding.

2.2 Question 3 (3 points)

We can use L 0 distance because it counts number of disagreeing features in our sample.

3 Analysis of KNN

3.1 Question 4 (2 points)

There are two cases to be considered here: (i) when the query point lies outside the circle, (ii) when the query point lies inside the circle. When the query point lies inside the circle, from the diagram it is easy to see that the closest point to x will be a point on the circumference of the circle, xa, while the farthest point xb will be the point on the circumference at 180o^ from xa. Therefore, lc = dist(x, xc) − r, and uc = dist(x, xc) + r For the second case: the closest point, xa, may be the same point as x, therefore, lc = 0. The upper bound uc will be the same. Taken the above cases together, we can write lower bound as:

lc = max(0, d(x, xc) − r) (2)

3.2 Question 5 (2 points)

For this section we’ll work with tighter lower bound: la = d(x, xa) − r.

uc < lad(x, xc) + r < d(x, xa) − rd(x, xc) + 2r < d(x, xa)

3.3 Question 6 (6 points)

The prediction algorithm is very simple. Given a total of M of balls (B)(xc, r); c = 1 : M with radius r and the count of training points covered by each ball Nc, we first compute the