private void putLastKeywords() {
		//put the last time frame keywords into 
		
		/*//check if there are keywords in last time frame but not in this time frame 
		//(given the condition that there is space remaining)
		if(newKeywords.size()<Settings.keywordMax){
			for(String lastKey : Settings.TFHashtagFreq_last.keySet().toArray(new String[Settings.TFHashtagFreq_last.size()])){
				if(!newKeywords.contains(lastKey))
					newKeywords.add(lastKey);
			}
		}

		//kept for adding last time frame keywords
		if(Settings.TFHashtagFreq_last.size()!=0){
			Settings.TFHashtagFreq_last.clear();
		}
		Settings.TFHashtagFreq_last = new TreeMap<String,Integer>(TFFreq);*/
		int count = 0;
		String temp = "";
		if(TFFreq.size()<Settings.keywordMax){
			for(String lastKey : Settings.TFHashtagFreq_last.keySet().toArray(new String[Settings.TFHashtagFreq_last.size()])){
				if(!TFFreq.keySet().contains(lastKey)){
					TFFreq.put(lastKey,Settings.TFHashtagFreq_last.get(lastKey));
					TFFreq_sample.put(lastKey, Settings.TFHashtagFreq_sample_last.get(lastKey));
					count++;
					temp+=lastKey+", ";
				}
			}
		}
		System.out.printf("************ %3d ************ Added Last Frame Keywords: %s\n",count,temp);
		
		Settings.TFHashtagFreq_last.clear();
		Settings.TFHashtagFreq_sample_last.clear();
		
		//Settings.TFHashtagFreq_last = new TreeMap<String,Integer>(TFFreq);
		//Settings.TFHashtagFreq_sample_last = new TreeMap<String,double[]>(TFFreq_sample);
	}