diff --git a/gridappsd-python-lib/gridappsd/simulation.py b/gridappsd-python-lib/gridappsd/simulation.py
index c1b77bf..9a65592 100644
--- a/gridappsd-python-lib/gridappsd/simulation.py
+++ b/gridappsd-python-lib/gridappsd/simulation.py
@@ -42,11 +42,11 @@ def asdict(self):
 
 @dataclass
 class ModelCreationConfig(ConfigBase):
-    load_scaling_factor: str = field(default="1")
+    load_scaling_factor: float = field(default=1)
     schedule_name: str = field(default="ieeezipload")
-    z_fraction: str = field(default="0")
-    i_fraction: str = field(default="1")
-    p_fraction: str = field(default="0")
+    z_fraction: float = field(default=0)
+    i_fraction: float = field(default=1)
+    p_fraction: float = field(default=0)
     randomize_zipload_fractions: bool = field(default=False)
     use_houses: bool = field(default=False)
 
@@ -56,14 +56,28 @@ class ModelCreationConfig(ConfigBase):
 
 @dataclass
 class SimulationArgs(ConfigBase):
-    start_time: str = field(default="1655321830")
-    duration: str = field(default="300")
-    timestep_frequency: str = field(default="1000")
-    timestep_increment: str = field(default="1000")
+    start_time: int = field(default=1655321830)
+    duration: int = field(default=300)
+    publish_period: int = field(default=None)
+    interval: int = field(default=None)
     run_realtime: bool = field(default=True)
     pause_after_measurements: bool = field(default=False)
     simulation_name: str = field(default="ieee13nodeckt")
 
+    def __post_init_(self):
+        if self.run_realtime:
+            self.interval = 1
+            if not self.publish_period:
+                self.publish_period = 3
+        else:
+            if not self.interval:
+                self.interval = 60
+            if not self.publish_period:
+                self.publish_period = 60
+        if self.publish_period < self.interval:
+            raise RuntimeError("A simulation's publishing_period cannot be less than the simulation's timestep "
+                               f"interval. please make the publishing_period >= interval!")
+
 
 @dataclass
 class SimulatorArgs(ConfigBase):
diff --git a/gridappsd-python-lib/tests/test_simulation.py b/gridappsd-python-lib/tests/test_simulation.py
index 47dcceb..76dd8e2 100644
--- a/gridappsd-python-lib/tests/test_simulation.py
+++ b/gridappsd-python-lib/tests/test_simulation.py
@@ -16,50 +16,57 @@
 
 @pytest.fixture
 def createGadObject():
-   gad_user = os.environ.get('GRIDAPPSD_USER')
-   if gad_user is None:
-       os.environ['GRIDAPPSD_USER'] = 'system'
-   gad_password = os.environ.get('GRIDAPPSD_PASSWORD')
-   if gad_password is None:
-       os.environ['GRIDAPPSD_PASSWORD'] = 'manager'
-   return GridAPPSD()
+    gad_user = os.environ.get('GRIDAPPSD_USER')
+    if gad_user is None:
+        os.environ['GRIDAPPSD_USER'] = 'system'
+    gad_password = os.environ.get('GRIDAPPSD_PASSWORD')
+    if gad_password is None:
+        os.environ['GRIDAPPSD_PASSWORD'] = 'manager'
+    return GridAPPSD()
 
 @pytest.mark.integration
 def test_createSimulations(createGadObject):
-   gadObj = createGadObject
-   response = gadObj.query_model_info()
-   models = response.get("data", {}).get("models", {})
-   start_time = int(datetime(year=2025, month=1, day=1, hour=0, minute=0, second=0, microsecond=0, tzinfo=timezone.utc).timestamp())
-   simulationArgs = SimulationArgs(start_time=f"{start_time}",
-                                   duration="120",
-                                   run_realtime=False,
-                                   pause_after_measurements=False)
-   sim_config = SimulationConfig(simulation_config=simulationArgs)
-   modelsToRun = [
-       "49AD8E07-3BF9-A4E2-CB8F-C3722F837B62", # IEEE 13 Node Test Feeder
-       "C1C3E687-6FFD-C753-582B-632A27E28507"  # IEEE 123 Node Test Feeder
-   ]
-   for m in models:
-       if m.get("modelId") not in modelsToRun:
-           continue
-       line_name = m.get("modelId")
-       subregion_name = m.get("subRegionId")
-       region_name = m.get("regionId")
-       psc = PowerSystemConfig(Line_name=line_name,
-                               SubGeographicalRegion_name=subregion_name,
-                               GeographicalRegion_name=region_name)
-       sim_config.power_system_configs.append(psc)
-   sim_obj = Simulation(gapps=gadObj, run_config=sim_config)
-   def on_measurement(sim, ts, m):
-       global measurements_received
-       measurements_received += 1
-   def on_simulation_complete(sim):
-       global simulation_is_complete
-       simulation_is_complete = True
-   sim_obj.add_onmeasurement_callback(on_measurement)
-   sim_obj.add_oncomplete_callback(on_simulation_complete)
-   sim_obj.start_simulation()
-   while not simulation_is_complete:
-       time.sleep(1)
-   assert measurements_received == 1
-   gadObj.disconnect()
+    gadObj = createGadObject
+    response = gadObj.query_model_info()
+    models = response.get("data", {}).get("models", {})
+    start_time = int(datetime(year=2025,
+                              month=1,
+                              day=1,
+                              hour=0,
+                              minute=0,
+                              second=0,
+                              microsecond=0,
+                              tzinfo=timezone.utc).timestamp())
+    simulationArgs = SimulationArgs(start_time=f"{start_time}",
+                                    duration="120",
+                                    run_realtime=False,
+                                    pause_after_measurements=False)
+    sim_config = SimulationConfig(simulation_config=simulationArgs)
+    modelsToRun = [
+        "49AD8E07-3BF9-A4E2-CB8F-C3722F837B62", # IEEE 13 Node Test Feeder
+        "C1C3E687-6FFD-C753-582B-632A27E28507"  # IEEE 123 Node Test Feeder
+    ]
+    for m in models:
+        if m.get("modelId") not in modelsToRun:
+            continue
+        line_name = m.get("modelId")
+        subregion_name = m.get("subRegionId")
+        region_name = m.get("regionId")
+        psc = PowerSystemConfig(Line_name=line_name,
+                                SubGeographicalRegion_name=subregion_name,
+                                GeographicalRegion_name=region_name)
+        sim_config.power_system_configs.append(psc)
+    sim_obj = Simulation(gapps=gadObj, run_config=sim_config)
+    def on_measurement(sim, ts, m):
+        global measurements_received
+        measurements_received += 1
+    def on_simulation_complete(sim):
+        global simulation_is_complete
+        simulation_is_complete = True
+    sim_obj.add_onmeasurement_callback(on_measurement)
+    sim_obj.add_oncomplete_callback(on_simulation_complete)
+    sim_obj.start_simulation()
+    while not simulation_is_complete:
+        time.sleep(1)
+    assert measurements_received == 1
+    gadObj.disconnect()