# Questions tagged [smoothing]

Smoothing methods in data analysis, like splines or kernel smoothers, also regression smoothers like lowess.

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### How does Kneser Ney estimate ngrams with BOS without dividing by zero?

The recursive formula for (unmodified) Kneser Ney smoothing is (per Jurafsky08 3.40) $P_{KN}(w_i | h) = \frac{\text{max}(c_{KN}(h\ w_i) - d, 0)}{\sum_v c_{KN}(h \ v )} + \lambda(h) P_{KN}(w_i | h)$ ...
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### Assessing probability that one set of measurements extends the other with Kalman smoother

I have two sets of N-dimensional measurements following each other with a certain time gap in between. Let's name those sets $A$ and $B$, respectively. All observations have constant Gaussian white ...
12 views

### Why would you smooth a logical variable in a GAM?

I just used the gam.scope function in the R-package gam to create possible scopes of each explanatory variable of my model to ...
104 views

### Is it possible to use smooth functions as part of a nonlinear regression?

Background I am fitting nonlinear regressions with a single response and two predictors. I know the relationship between the response and each of the predictors, but I do not know how they interact. I ...
41 views

### Inferences with Filtered and Smoothed state estimates from a tracking problem

I am working on a synthetic tracking problem in a two-dimensional space, where the start and end positions are known and noisy measurements of the state variables are given at discrete time steps. As ...
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### How does lowess handle gaps in time series?

I have been using the lowess smoother to calculate trends for time series data for a while now but until now my data was always without gaps. I now have to work with data where there are quite large ...
1 vote
50 views

### Understanding Identifiability problem of multiple smooths in GAMs/Additive models

I am a beginner into additive models and GAMs, but have good enough knowledge of linear regression. I was going through this wikipedia article to understand more, but can't seem to understand the ...
1 vote
52 views

### Smoothing of GPS tracks - remove noise and stop-go clusters

I know there are several posts about this, but I could not find exactly what I need. I have GPS track data (from an underwater vehicle) for short intervals of 1 second (time-stamps on data). The data ...
1 vote
48 views

### Functional Data Analysis with Missing Data

I am trying to analyze a dataset containing several observations for n = 27. Unfortunately, not every participant answered the question every time, i.e., when plotting the graph it has holes in it. I ...
39 views

### GAM partial response plot interpretation

I've made the gam in the code below (in R), but I'm struggling to interpret the results. Specifically, the partial response plots for all but one of the variables is linear, and the CI lines cross in ...
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### Smoothing without losing data points

How would I smooth a series of data without losing the ends of a series? For example, if I have $i_1, i_2, \dots, i_n$, and I apply a moving average, I lose the start and end of the series ($i_1$ and \$...
1 vote
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### Kernel Smoothing for Time Series data

I have generated a time series data set of measurements that are a bit noisy and I want to apply kernel smoothing to the data. My time series data is not regular however, meaning that the time ...
268 views

### How 'by' factor works with 'fs' random smooth in gam?

I've a large dataset including a response bmk, a continuous predictor delay, a group factor (...
1 vote
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### Is there a statistically sound method of smoothing a data series without removing the edges?

Recently I've been plotting a lot of data, and often I find myself using a moving average to smooth out values that oscillate or otherwise fluctuate a lot. However, the problem with this is that it ...
62 views

### Assessing differences in slope of a loess (or any smoother) fit

I have continuous data for x (for example "time") and y with several groups. I would like to show/test that the slope of groupC changes over time (is positive and rises) while groups A and B ...
126 views

### Gam plots y-axis range is different for model that that from predict function

I got some idea about gam (generalized additive model) plot from a course of Noam Ross. However, I have several confusion and got stucked. I fit a logistic gam and can interpret by using ...
39 views

### The difference between smoothing problems in stochastic processes and statistics

I am taking a class and we are about to talk about Kalman filters and smoothing and I am trying to do some reading ahead. On the Wikipedia page for 'Smoothing (stochastic processes)' it says 'the ...
178 views

### Spline basis explicitly including a linear term; basis functions generated by the default call to "s()" function of mgcv package

I'm curious about the basis functions generated by the call to "s()" function with default parameter values, but even more specifically I'm curious about a smoother for a single variable ...
66 views

### Why smoothCon gives different estimates of smooths than mgcv?

I am learning gam by myself. I tried to find posts that can help me to finding and understanding smooth functions i.e., basis functions from gam using mgcv. From a ... 1 vote
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### GAM: covariate specific fits do not appear to match approximate significance of smooth terms

I have fit a GAM with two continuous independent variables and one discrete covariate with two levels ("gray" and "brown"). All variables are scaled and the model runs fine: ...
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### How to show that the gradient of the smoothed surrogate loss function leads to perceptron update?

This is about the contents of section 1.2.1 and 1.2.1.1 of the book "Neural Networks and Deep Learning: A Textbook". The link to the sections is here. The question arises from the following ...
67 views

### What is the name of this kind of smoothing?

Essentially, the code below produces something that is similar to a running mean, but instead of 0/1 weights on a window, it has gaussian weights centered at the x-position in consideration. I'm ...
1 vote