diff --git a/.github/workflow/install_learnware_with_source.yaml b/.github/workflow/install_learnware_with_source.yaml
index bfe4e9c..e9589e3 100644
--- a/.github/workflow/install_learnware_with_source.yaml
+++ b/.github/workflow/install_learnware_with_source.yaml
@@ -1,4 +1,4 @@
-name: Test leanrnware from pip
+name: Test leanrnware from source code
 
 on:
   push:
diff --git a/learnware/specification/__init__.py b/learnware/specification/__init__.py
index 0bb0502..28100e7 100644
--- a/learnware/specification/__init__.py
+++ b/learnware/specification/__init__.py
@@ -1,3 +1,3 @@
 from .utils import generate_stat_spec
 from .base import Specification, BaseStatSpecification
-from .table import RKMEStatSpecification
+from .regular import RKMEStatSpecification
diff --git a/learnware/specification/base.py b/learnware/specification/base.py
index 655e5a4..1c340fa 100644
--- a/learnware/specification/base.py
+++ b/learnware/specification/base.py
@@ -15,11 +15,8 @@ class BaseStatSpecification:
         """
         self.type = type
 
-    def generate_stat_spec_from_data(self, **kwargs):
-        """Construct statistical specification from raw dataset
-        - kwargs may include the feature, label and model
-        - kwargs also can include hyperparameters of specific method for specifaction generation
-        """
+    def generate_stat_spec(self, **kwargs):
+        """Construct statistical specification"""
         raise NotImplementedError("generate_stat_spec_from_data is not implemented")
 
     def save(self, filepath: str):
diff --git a/learnware/specification/regular/__init__.py b/learnware/specification/regular/__init__.py
new file mode 100644
index 0000000..64fe041
--- /dev/null
+++ b/learnware/specification/regular/__init__.py
@@ -0,0 +1 @@
+from .table import RKMEStatSpecification
diff --git a/learnware/specification/regular/base.py b/learnware/specification/regular/base.py
new file mode 100644
index 0000000..48a7e1f
--- /dev/null
+++ b/learnware/specification/regular/base.py
@@ -0,0 +1,13 @@
+from ..base import BaseStatSpecification
+
+
+class RegularStatsSpecification(BaseStatSpecification):
+    def generate_stat_spec(self, **kwargs):
+        self.generate_stat_spec_from_data(**kwargs)
+
+    def generate_stat_spec_from_data(self, **kwargs):
+        """Construct statistical specification from raw dataset
+        - kwargs may include the feature, label and model
+        - kwargs also can include hyperparameters of specific method for specifaction generation
+        """
+        raise NotImplementedError("generate_stat_spec_from_data is not implemented")
diff --git a/learnware/specification/table/__init__.py b/learnware/specification/regular/table/__init__.py
similarity index 100%
rename from learnware/specification/table/__init__.py
rename to learnware/specification/regular/table/__init__.py
diff --git a/learnware/specification/table/rkme.py b/learnware/specification/regular/table/rkme.py
similarity index 99%
rename from learnware/specification/table/rkme.py
rename to learnware/specification/regular/table/rkme.py
index 9769800..32dea8d 100644
--- a/learnware/specification/table/rkme.py
+++ b/learnware/specification/regular/table/rkme.py
@@ -20,8 +20,8 @@ try:
 except ImportError:
     _FAISS_INSTALLED = False
 
-from ..base import BaseStatSpecification
-from ...logger import get_module_logger
+from ..base import RegularStatsSpecification
+from ....logger import get_module_logger
 
 logger = get_module_logger("rkme")
 
@@ -30,7 +30,7 @@ if not _FAISS_INSTALLED:
     logger.warning('Please run "conda install -c pytorch faiss-cpu" first.')
 
 
-class RKMEStatSpecification(BaseStatSpecification):
+class RKMEStatSpecification(RegularStatsSpecification):
     """Reduced Kernel Mean Embedding (RKME) Specification"""
 
     def __init__(self, gamma: float = 0.1, cuda_idx: int = -1):
diff --git a/learnware/specification/system/__init__.py b/learnware/specification/system/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/learnware/specification/system/heter_table.py b/learnware/specification/system/heter_table.py
new file mode 100644
index 0000000..ae24a1c
--- /dev/null
+++ b/learnware/specification/system/heter_table.py
@@ -0,0 +1,15 @@
+from ..base import BaseStatSpecification
+
+
+class HeterMapTableSpecification(BaseStatSpecification):
+    def generate_stat_spec(self, **kwargs):
+        pass
+
+    def save(self, filepath: str):
+        pass
+
+    def load(self, filepath: str):
+        pass
+
+    def dist(self, other_spec):
+        pass
diff --git a/learnware/specification/utils.py b/learnware/specification/utils.py
index c3693b7..5f1a689 100644
--- a/learnware/specification/utils.py
+++ b/learnware/specification/utils.py
@@ -4,7 +4,7 @@ import pandas as pd
 from typing import Union
 
 from .base import BaseStatSpecification
-from .table import RKMEStatSpecification
+from .regular import RKMEStatSpecification
 from ..config import C