NLP-WordPrediction

Two Shiny applications:

• single word prediction: https://kamfonas.shinyapps.io/NLP_App1/
• Dynamic list prediction: https://kamfonas.shinyapps.io/NLP_App/

• Type or paste a partial sentence in the input text box and click on the buton to predict next word
• One next word prediction is returned
• Application is under 1GB and loads with default settings
• A delay is experienced if the server needs to be restarted
• If the input textbox is empty, the user sees an error message.
• To manage space:
  • Only top-1 ranking prediction is retained in the model
  • Certain N-grams that result in equivalent predictions from the next lower (N-1)-gram were eliminated

• Predictions are generated reactively as text is typed.
• If the last character is a space, the next word is predicted.
• Predictions are filtered so they match the prefix after each character typed.
• A prioritized list of predictions is returned. The user can control its length or show all predictions by setting the length to zero.
• Ranks and scores of the predictions are included.
• The server takes over a minute to start but predictions are fast, keeping up with typing new characters.

• Based on example data from Blogs, Twits and News
• The text was preprocessed as follows:
  • Breakdown into sentences
  • Eliminate white space and convert to lower case
  • Expand contractions (like it’s, hasn’t etc.)
  • Replace start of sentences, numerics, URLs, E-Mail addresses etc. with special generic tokens.

• N-grams are generated and conditional probabilities calculated from counts.
• A simple back-off model is used from 4-grams to bi-grams until match is found