diff --git a/src/main/java/org/gcube/data/analysis/wps/CancelComputation.java b/src/main/java/org/gcube/data/analysis/wps/CancelComputation.java
index b97c2f7..adb626e 100644
--- a/src/main/java/org/gcube/data/analysis/wps/CancelComputation.java
+++ b/src/main/java/org/gcube/data/analysis/wps/CancelComputation.java
@@ -1,6 +1,5 @@
 package org.gcube.data.analysis.wps;
 
-import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@@ -14,9 +13,8 @@ import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
 import org.apache.commons.lang.StringUtils;
+import org.gcube.data.analysis.wps.processes.Processes;
 import org.n52.wps.commons.XMLUtil;
-import org.n52.wps.server.database.DatabaseFactory;
-import org.n52.wps.server.database.IDatabase;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -48,16 +46,16 @@ public class CancelComputation extends HttpServlet {
 		// id of result to retrieve.
 		String id = request.getParameter("id");
 		
-		LOGGER.debug("CANCEL COMPUTATION -> RETRIEVING ID " + id);
+		LOGGER.debug("CANCEL COMPUTATION -> RETRIEVING ID {}", id);
 		if (StringUtils.isEmpty(id)) {
 			errorResponse("id parameter missing", response);
 		} else {
-			LOGGER.debug("CANCEL COMPUTATION -> ID RETRIEVED " + id);
+			LOGGER.debug("CANCEL COMPUTATION -> ID {} RETRIEVED ", id);
 			if (!isIDValid(id)) {
 				errorResponse("id parameter not valid", response);
 			}
-			LOGGER.debug("CANCEL COMPUTATION -> ID IS VALID " + id);
-			IDatabase db = DatabaseFactory.getDatabase();
+			LOGGER.debug("CANCEL COMPUTATION -> ID {} IS VALID ",id);
+			/*IDatabase db = DatabaseFactory.getDatabase();
 			long len = db.getContentLengthForStoreResponse(id);
 			LOGGER.debug("CANCEL COMPUTATION -> INITIAL ID RESPONSE LENGTH " + len);
 			
@@ -78,8 +76,14 @@ public class CancelComputation extends HttpServlet {
 			} catch (Exception e) {
 				LOGGER.error("error in do get",e);
 			} finally {
-			}
+			}*/
+			if (Processes.getRunningProcesses().containsKey(id)){
+				boolean cancelled = Processes.getRunningProcesses().get(id).cancel();
+				if(!cancelled)
+					LOGGER.debug("CANCEL COMPUTATION -> process with id {} already cancelled ", id);
+			} else LOGGER.debug("CANCEL COMPUTATION -> no running process with id {} (probably it already finished) ", id);
 		}
+		
 	}
 
 	protected void errorResponse(String error, HttpServletResponse response) throws IOException {
diff --git a/src/main/java/org/gcube/data/analysis/wps/ExecuteRequest.java b/src/main/java/org/gcube/data/analysis/wps/ExecuteRequest.java
index 105aa98..571b562 100644
--- a/src/main/java/org/gcube/data/analysis/wps/ExecuteRequest.java
+++ b/src/main/java/org/gcube/data/analysis/wps/ExecuteRequest.java
@@ -598,6 +598,7 @@ public class ExecuteRequest extends Request implements IObserver {
 			}
 			if (algorithm instanceof AbstractEcologicalEngineMapper) {
 				((AbstractEcologicalEngineMapper) algorithm).setWpsExternalID(wpsid);
+				((AbstractEcologicalEngineMapper) algorithm).setObserver(GCubeObserver.getObserver());
 			}
 			
 			if (algorithm instanceof AbstractTransactionalAlgorithm) {
diff --git a/src/main/java/org/gcube/data/analysis/wps/GCubeObserver.java b/src/main/java/org/gcube/data/analysis/wps/GCubeObserver.java
new file mode 100644
index 0000000..63d543a
--- /dev/null
+++ b/src/main/java/org/gcube/data/analysis/wps/GCubeObserver.java
@@ -0,0 +1,38 @@
+package org.gcube.data.analysis.wps;
+
+import org.gcube.data.analysis.wps.processes.Processes;
+import org.gcube.dataanalysis.wps.statisticalmanager.synchserver.mapping.AbstractEcologicalEngineMapper;
+import org.gcube.dataanalysis.wps.statisticalmanager.synchserver.utils.Observable;
+import org.gcube.dataanalysis.wps.statisticalmanager.synchserver.utils.Observer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class GCubeObserver implements Observer{
+
+	private static final Logger LOGGER = LoggerFactory.getLogger(GCubeObserver.class);
+	
+	public static GCubeObserver getObserver(){
+		return instance;
+	}
+	
+	private static GCubeObserver instance = new GCubeObserver();
+		
+	private GCubeObserver(){}
+	
+	@Override
+	public void isFinished(Observable o) {
+		AbstractEcologicalEngineMapper algorithm = (AbstractEcologicalEngineMapper)o;
+		LOGGER.debug("computation with id {} finished",algorithm.wpsExternalID);
+		Processes.getRunningProcesses().remove(algorithm.wpsExternalID);		
+	}
+
+	@Override
+	public void isStarted(Observable o) {
+		AbstractEcologicalEngineMapper algorithm = (AbstractEcologicalEngineMapper)o;
+		LOGGER.debug("computation with id {} started",algorithm.wpsExternalID);
+		Processes.getRunningProcesses().put(algorithm.wpsExternalID,algorithm);	
+	}
+
+	
+	
+}
diff --git a/src/main/java/org/gcube/data/analysis/wps/processes/Processes.java b/src/main/java/org/gcube/data/analysis/wps/processes/Processes.java
index 78f1a5c..fd2f0b0 100644
--- a/src/main/java/org/gcube/data/analysis/wps/processes/Processes.java
+++ b/src/main/java/org/gcube/data/analysis/wps/processes/Processes.java
@@ -3,22 +3,15 @@ package org.gcube.data.analysis.wps.processes;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
-import java.util.WeakHashMap;
 
 import org.gcube.dataanalysis.wps.statisticalmanager.synchserver.utils.Cancellable;
 
 public class Processes {
 
-	private Map<String, Cancellable> runningProcesses = Collections.synchronizedMap(new HashMap<String, Cancellable>());
-	
-	private Map<String, Cancellable> cancelledProcesses = Collections.synchronizedMap(new WeakHashMap<String, Cancellable>());
+	private static Map<String, Cancellable> runningProcesses = Collections.synchronizedMap(new HashMap<String, Cancellable>());
 
-	public Map<String, Cancellable> getRunningProcesses() {
+	public static Map<String, Cancellable> getRunningProcesses() {
 		return runningProcesses;
 	}
 
-	public Map<String, Cancellable> getCancelledProcesses() {
-		return cancelledProcesses;
-	}
-	
 }
diff --git a/src/main/webapp/WEB-INF/README b/src/main/webapp/WEB-INF/README
index 61fbb2e..cbf1700 100644
--- a/src/main/webapp/WEB-INF/README
+++ b/src/main/webapp/WEB-INF/README
@@ -25,7 +25,7 @@ no. 654119), SoBigData (grant no. 654024);
 Version
 --------------------------------------------------
  
-1.0.0-SNAPSHOT (${maven.build.timestamp})
+1.0.0-SNAPSHOT (2017-07-12)
  
 Please see the file named "changelog.xml" in this directory for the release notes.