How to determine initial values in Kalman Filter
but the output signal in the paper is much smoother than my output and


I don't know which paper we're referring to, but it's far from uncommon that you'd smoothen your output for plotting – it would be adequate to specify how you did that, but notice that this sadly doesn't mean everyone adheres to that practice.


  vertical axis is different in my case


that might just be a scaling error, and is not necessarily bad. Again, we don't know which paper is about and whether you're working on exactly the same data, but the fact alone that your line is much thinner and looks like it has more points indicates that they applied some smoothing and/or normalization.


  I think that is because of Kalman filter initialization; initial state and predict.


I don't see indications for that. On the contrary, assuming things converge, I'd say your initial state is fine.