diff --git a/README.md b/README.md
index 55f4c0c..41acf51 100644
--- a/README.md
+++ b/README.md
@@ -15,10 +15,28 @@ pip3 install roslibpy
 https://pypi.python.org/pypi/service_identity
 ```
 
+## Building docker image
+```bash
+sudo docker build -t rosgraph_monitor:0.1 .
+sudo docker run -it rosgraph_monitor:0.1
+//once inside the image
+roscore
+```
+In a new terminal
+```bash
+sudo docker ps -l
+// check for NAMES
+sudo docker exec -it NAME bash
+//once inside the image
+source /graph_ws/devel/setup.bash
+rosrun rosgraph_monitor monitor
+```
+
+
 ## Running the system  
 ```
 roslaunch rosbridge_server rosbridge_websocket.launch
 roslaunch rosgraph_monitor demo.launch
 python3 src/rosgraph_monitor/nav_model.py
 rosservice call /load_observer "name: 'NavObserver'"
-```
+```
\ No newline at end of file
diff --git a/docker/Dockerfile b/docker/Dockerfile
new file mode 100644
index 0000000..fc07740
--- /dev/null
+++ b/docker/Dockerfile
@@ -0,0 +1,16 @@
+FROM osrf/ros:melodic-desktop-bionic
+
+RUN apt-get update \
+    && apt-get install -y git \
+                          python-catkin-tools                           
+
+RUN mkdir -p /graph_ws/src 
+WORKDIR /graph_ws/src
+RUN git clone --depth=1 -b nav_observer https://github.com/ipa-hsd/rosgraph_monitor/
+RUN git clone --depth=1 -b SoSymPaper https://github.com/ipa-nhg/ros_graph_parser
+
+WORKDIR /graph_ws/
+RUN rosdep install --from-paths src --ignore-src -r -y
+RUN . /opt/ros/melodic/local_setup.sh \
+    && catkin build \
+    && . devel/local_setup.sh
diff --git a/docker/ros_entrypoint.sh b/docker/ros_entrypoint.sh
new file mode 100644
index 0000000..5f6588a
--- /dev/null
+++ b/docker/ros_entrypoint.sh
@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+set -e
+
+# setup ros environment
+source "graph_ws/devel/setup.bash"
+exec "$@"
\ No newline at end of file
diff --git a/src/rosgraph_monitor/observer.py b/src/rosgraph_monitor/observer.py
index fc1fda9..9b39ccf 100644
--- a/src/rosgraph_monitor/observer.py
+++ b/src/rosgraph_monitor/observer.py
@@ -57,11 +57,15 @@ def _stopped(self):
 
 class ServiceObserver(Observer):
     def __init__(self, name, service_name=None, service_type=None, loop_rate_hz=1):
+        super(ServiceObserver, self).__init__(name, loop_rate_hz)
         self.name = service_name
         self.type = service_type
         self.client = None
-        self.start_service()
-        super(ServiceObserver, self).__init__(name, loop_rate_hz)
+        try:
+            self.start_service()
+        except:
+            print("{} service not started".format(self.name))
+            super.__del__()
 
     def start_service(self):
         try:
@@ -89,10 +93,10 @@ def diagnostics_from_response(self, response):
 
 class TopicObserver(Observer):
     def __init__(self, name, loop_rate_hz, topics):
+        super(TopicObserver, self).__init__(name, loop_rate_hz)
         self._topics = topics
         self._id = ""
         self._num_topics = len(topics)
-        super(TopicObserver, self).__init__(name, loop_rate_hz)
 
     # Every derived class needs to override this
     def calculate_attr(self, msgs):
diff --git a/src/rosgraph_monitor/parser.py b/src/rosgraph_monitor/parser.py
index bb106cc..1f40e6d 100644
--- a/src/rosgraph_monitor/parser.py
+++ b/src/rosgraph_monitor/parser.py
@@ -34,7 +34,8 @@ def __init__(self, model, isFile=True):
         # CSB = Close Square Bracket ]
 
         OCB, CCB, ORB, CRB, SQ, OSB, CSB = map(Suppress, "{}()'[]")
-        name = SQ + Word(printables, excludeChars="{},'") + SQ
+        name = Optional(SQ) + Word(printables,
+                                   excludeChars="{},'") + Optional(SQ)
 
         real = Combine(Word(nums) + '.' + Word(nums))
 
@@ -99,6 +100,11 @@ def __init__(self, model, isFile=True):
         _from = Keyword("From").suppress()
         _to = Keyword("To").suppress()
 
+        # global parameters Def
+        _g_parameters = Keyword("Parameters").suppress()
+        _g_parameter = Keyword("Parameter").suppress()
+        _type = Keyword("type").suppress()
+
         listStr << delimitedList(Group(OCB + delimitedList(values) + CCB))
         mapStr << (OSB + delimitedList(Group(OCB + delimitedList((Group(
             sglQuotedString.setParseAction(removeQuotes) + Suppress(":") + values))) + CCB)) + CSB)
@@ -148,6 +154,11 @@ def __init__(self, model, isFile=True):
         topic_connections = (_topic_connections + OCB +
                              OneOrMore(topic_connection + Optional(",").suppress()) + CCB)
 
+        g_parameter = Group(_g_parameter + OCB + _name + name("param_name") +
+                            _type + name("value_type") + param_value("param_value") + CCB)
+        g_parameters = (_g_parameters + OCB +
+                      OneOrMore(g_parameter + Optional(",").suppress()) + CCB)
+
         interface = Group(
             _interface +
             OCB +
@@ -165,8 +176,9 @@ def __init__(self, model, isFile=True):
             OCB + \
             _name + name("system_name") + \
             _component + ORB + \
-            OneOrMore(interface + Optional(",").suppress())("interfaces") + \
-            CRB + Optional(topic_connections)("topic_connections") + CCB
+            OneOrMore(interface + Optional(",").suppress())("interfaces") + CRB \
+            + Optional(topic_connections)("topic_connections") \
+            + Optional(g_parameters)("global_parameters") + CCB
         self._model = model
         self._isFile = isFile
 
@@ -177,6 +189,7 @@ def _parse_from_file(self):
         self._result = self.rossystem_grammar.parseFile(self._model)
 
     def parse(self):
+        self._result = ParseResults()
         try:
             if self._isFile:
                 self._parse_from_file()