Question : Select the correct characteristics of unsupervised learning
1. Unsupervised learning is that of trying to find hidden structure in unlabeled data 2. There is no error or reward signal to evaluate a potential solution 3. Access Mostly Uused Products by 50000+ Subscribers 4. Only 1 and 2 5. All 1,2 and 3
In machine learning, the problem of unsupervised learning is that of trying to find hidden structure in unlabeled data. Since the examples given to the learner are unlabeled, there is no error or reward signal to evaluate a potential solution. This distinguishes unsupervised learning from supervised learning and reinforcement learning.
Unsupervised learning is closely related to the problem of density estimation in statistics. However unsupervised learning also encompasses many other techniques that seek to summarize and explain key features of the data. Many methods employed in unsupervised learning are based on data mining methods used to preprocess [citation needed] data.
Question : Unsupervised learning can be used for bridging the causal gap between input and output observations 1. True 2. False
Correct Answer : Get Lastest Questions and Answer : With unsupervised learning it is possible to learn larger and more complex models than with supervised learning. This is because in supervised learning one is trying to find the connection between two sets of observations. The difficulty of the learning task increases exponentially in the number of steps between the two sets and that is why supervised learning cannot, in practice, learn models with deep hierarchies.
In unsupervised learning, the learning can proceed hierarchically from the observations into ever more abstract levels of representation. Each additional hierarchy needs to learn only one step and therefore the learning time increases (approximately) linearly in the number of levels in the model hierarchy.
If the causal relation between the input and output observations is complex -- in a sense there is a large causal gap -- it is often easier to bridge the gap using unsupervised learning instead of supervised learning. This is depicted in figure 3. Instead of finding the causal pathway from inputs to outputs, one starts building the model upwards from both sets of observations in the hope that in higher levels of abstraction the gap is easier to bridge. Notice also that the input and output observations are in symmetrical positions in the model.
Unsupervised learning can be used for bridging the causal gap between input and output observations. The latent variables in the higher levels of abstraction are the causes for both sets of observations and mediate the dependence between inputs and outputs.