Summer 2011 (TA)
- Research: Gram Matrix approximation
- Recap:
- Problem: kerenl methods gram matrix is $O(N^2)$, which is computational and memory usage infiseable for large-scale datasets
- Prevoius Work:
- Low rank matrix approximation:
- using EginDecomposition: Optimal solution but reqiures <math>O(N^3)</math> computation to constuct the low rank matix
- Solution: use Nysrom therorem to approximate the eigen decomposition of the matrix which reqiures <math>O(m^2N)</math> where m << N.
- Low rank matrix approximation:
- Recap:
- Problem: In this methods in despite of reduce the computation complexity still we need <math>O(N^2)</math> to store the matrix, so the next method reduce both computation and memory.
- Efficient implementation for computing the kernel matrix:
- Using Spatial Indexing:
- Efficient implementation for computing the kernel matrix:
using Z-order, H-order, Td-tress and other spatial indexing techniques to order the points in the space and then use sliding window where the kernel function computed only between points in that wiondow.
- Problems: reqiures <math>O(NlogN)</math> as preprocessing to order the points, fails for very hight dimentional Data and hard to parallel
So we proposed a method that works fine foy large-scale and highly dimentinla data, overcome or pervoius work drwobbacks, easy to parallel, reqiures linear time preprocessing and reduce the computation and memory usae down form quadratic to subquadratic:
- Using Spatial Hashing or Locality sensitive hashing:
where the kerenl function and the cluster methods works on the buckets indicusally.
- LSH families :
- Random projection
- Hamming distance
- Eclidean Distance
- Cosine Distance
- Problem: assumes data uniforly distubuted solution:
- Spectral Hasing
- Random projection
- LSH families :
General Problem for random projection, it' doesnt take care of data comes in a kerenel space, Solution
- Kerenalized LSH
- Recap: Comparing differnt LSH families
Spring 2011 (TA/RA)
- Courses:
- CMPT 885: Special Topics in Computer Architecture
- CMPT 886: Special Topics in Operating Systems
Fall 2010 (FAS-GF/RA)
- Courses:
- CMPT 705: Design/Analysis Algorithms
- CMPT 820: Multimedia Systems
- Worked on Gram matrix approximation, High Performance/large scale application case studies
Summer 2010 (TA)
- Worked on large Scale Kernel methods
Spring 2010 (RA)
- Courses:
- CMPT 768: Sound Synthesis
- Worked on Locality sensitive hashing families and their applications and implementations