diff --git a/models/DTRAM/InventoryManagement.model b/models/DTRAM/InventoryManagement.model
new file mode 100644
index 0000000..578d56c
--- /dev/null
+++ b/models/DTRAM/InventoryManagement.model
@@ -0,0 +1,7 @@
+channel ItemRegistration {
+	out inventory(itemDB:Map, registerItem(itemId:Str, itemName:Str, quantity:Int)) = insert(itemDB, itemId, {"count": quantity, "name": itemName})
+}
+
+channel ReceivingOrShipping(itemId:Str) {
+	out inventory.{itemId}.count(prev_quantity:Int, receiveOrShip(quantity:Int)) = prev_quantity + quantity
+}
diff --git a/models/DTRAM/InventoryManagementCheckMinus.model b/models/DTRAM/InventoryManagementCheckMinus.model
new file mode 100644
index 0000000..e5c88d5
--- /dev/null
+++ b/models/DTRAM/InventoryManagementCheckMinus.model
@@ -0,0 +1,9 @@
+channel ItemRegistration {
+	out inventory(itemDB:Map, registerItem(itemId:Str, itemName:Str, quantity:Int)) = insert(itemDB, itemId, {"count": quantity, "name": itemName})
+}
+
+channel ReceivingOrShipping(itemId:Str) {
+	out inventory.{itemId}.count(prev_quantity:Int, receiveOrShip(quantity:Int)) = if(prev_quantity + quantity >= 0, 
+																						prev_quantity + quantity, 
+																						prev_quantity)
+}
diff --git a/models/DTRAM/InventoryManagementShippingReceiving.model b/models/DTRAM/InventoryManagementShippingReceiving.model
new file mode 100644
index 0000000..75888eb
--- /dev/null
+++ b/models/DTRAM/InventoryManagementShippingReceiving.model
@@ -0,0 +1,11 @@
+channel ItemRegistration {
+	out inventory(itemDB:Map, registerItem(itemId:Str, itemName:Str, quantity:Int)) = insert(itemDB, itemId, {"count": quantity, "name": itemName})
+}
+
+channel Receiving(itemId:Str) {
+	out inventory.{itemId}.count(prev_quantity:Int, receive(quantity:Int)) = prev_quantity + quantity
+}
+
+channel Shipping(itemId:Str) {
+	out inventory.{itemId}.count(prev_quantity:Int, ship(quantity:Int)) = prev_quantity - quantity
+}
diff --git a/models/DTRAM/SimpleTwitter.model b/models/DTRAM/SimpleTwitter.model
new file mode 100644
index 0000000..486fafb
--- /dev/null
+++ b/models/DTRAM/SimpleTwitter.model
@@ -0,0 +1,7 @@
+channel Signup {
+	out accounts(accountDB:Map, signUp(accountId:Str, name:Str)) = insert(accountDB, accountId, {"name": name, "tweets": nil})
+}
+
+channel Tweet(accountId:Str) {
+	out accounts.{accountId}.tweets(tweetList:List, tweet(contents:Str)) = append(tweetList, contents)
+}
diff --git a/models/DTRAM/SimpleTwitterChangeName.model b/models/DTRAM/SimpleTwitterChangeName.model
new file mode 100644
index 0000000..b206e97
--- /dev/null
+++ b/models/DTRAM/SimpleTwitterChangeName.model
@@ -0,0 +1,11 @@
+channel Signup {
+	out accounts(accountDB:Map, signUp(accountId:Str, name:Str)) = insert(accountDB, accountId, {"name": name, "tweets": nil})
+}
+
+channel Tweet(accountId:Str) {
+	out accounts.{accountId}.tweets(tweetList:List, tweet(contents:Str)) = append(tweetList, contents)
+}
+
+channel ChangeName(accountId:Str) {
+	out accounts.{accountId}.name(prevNamr:Str, changeName(name:Str)) = name
+}
diff --git a/models/DTRAM/SimpleTwitterDuplicateCheck.model b/models/DTRAM/SimpleTwitterDuplicateCheck.model
new file mode 100644
index 0000000..07de300
--- /dev/null
+++ b/models/DTRAM/SimpleTwitterDuplicateCheck.model
@@ -0,0 +1,9 @@
+channel Signup {
+	out accounts(accountDB:Map, signUp(accountId:Str, name:Str)) = if(contains(accountDB, accountId), 
+																		accountDB, 
+																		insert(accountDB, accountId, {"name": name, "tweets": nil}))
+}
+
+channel Tweet(accountId:Str) {
+	out accounts.{accountId}.tweets(tweetList:List, tweet(contents:Str)) = append(tweetList, contents)
+}