content: /* 
   * Copyright (C) 2015 Adrien Guille <adrien.guille@univ-lyon2.fr>
   *
   * This program is free software: you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation, either version 3 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
   */
  package main.java.fr.ericlab.sondy.algo.eventdetection;
  
  import main.java.fr.ericlab.sondy.core.app.AppParameters;
  import main.java.fr.ericlab.sondy.core.structures.Event;
  import main.java.fr.ericlab.sondy.algo.Parameter;
  import main.java.fr.ericlab.sondy.core.utils.HashMapUtils;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Set;
  import main.java.fr.ericlab.sondy.core.structures.Events;
  
  /**
   *
   *   @author Adrien GUILLE, ERIC Lab, University of Lyon 2
   *   @email adrien.guille@univ-lyon2.fr
   */
  public class PeakyTopics extends EventDetectionMethod {
      double minTermSupport = 0.0001;
      double maxTermSupport = 0.01;
      
      public PeakyTopics(){
          super();
          parameters.add(new Parameter("minTermSupport",minTermSupport+""));
          parameters.add(new Parameter("maxTermSupport",maxTermSupport+""));
      }
  
      @Override
      public String getName() {
          return "Peaky Topics";
      }
  
      @Override
      public String getCitation() {
          return "<li><b>Peaky Topics:</b> David A. Shamma, Lyndon Kennedy, Elizabeth F. Churchill (2011) Peaks and persistence: modeling the shape of microblog conversations, In Proceedings of the 2011 ACM Conference on Computer Supported Cooperative Work (CSCW), pp. 355-358</li>";
      }
      
      @Override
      public String getDescription() {
          return "Identifies highly localized events using a normalized term frequency based metric";
      }
  
      @Override
      public void apply() {
          double minTermOccur = parameters.getParameterValue("minTermSupport") * AppParameters.dataset.corpus.messageCount;
          double maxTermOccur = parameters.getParameterValue("maxTermSupport") * AppParameters.dataset.corpus.messageCount;
          Map<Event,Double> scores = new HashMap<>();
          for(int i = 0; i < AppParameters.dataset.corpus.vocabulary.size(); i++){
              String term = AppParameters.dataset.corpus.vocabulary.get(i);
              if(term.length()>1 && !AppParameters.stopwords.contains(term)){
                  double tf = 0, cf = 0;
                  int peakIndex = 0;
                  for(int j = AppParameters.timeSliceA; j < AppParameters.timeSliceB; j++){
                      cf += AppParameters.dataset.corpus.termFrequencies[i][j];
                      if(AppParameters.dataset.corpus.termFrequencies[i][j]>tf){
                          tf = AppParameters.dataset.corpus.termFrequencies[i][j];
                          peakIndex = j;
                      }
                  }
                  if(cf > minTermOccur && cf < maxTermOccur){
                      scores.put(new Event(term,AppParameters.dataset.corpus.convertTimeSliceToDay(peakIndex)+","+AppParameters.dataset.corpus.convertTimeSliceToDay(peakIndex+1)+""), tf/cf);
                  }
              }
          }
          scores = HashMapUtils.sortByDescValue(scores);
          Set<Map.Entry<Event, Double>> entrySet = scores.entrySet();
          events = new Events();
          for (Map.Entry<Event, Double> entry : entrySet) {
              events.list.add(entry.getKey());
          }
          events.setFullList();
      }
  }
  