Add "Why JADN?" content to Background intro paragraph

imjadn-v1.0-cn03.md

@@ -5,9 +5,9 @@
 
 # Information Modeling with JADN Version 1.0
 
-## Committee Note 02
+## Committee Note 03
 
-## 19 November 2024
+## 11 December 2024
 
 #### This stage:
 https://docs.oasis-open.org/openc2/imjadn/v1.0/cn01/imjadn-v1.0-cn01.md (Authoritative) \
@@ -223,6 +223,117 @@ clarity regarding the goals that the eventual implementation must satisfy. This
 section provides the background for the creation of JADN as an information
 modeling language for a spectrum of applications.
 
+JADN complements existing schema languages such as JSON Schema and XSD while
+providing distinctive features that focus on accurate definition of the
+information of interest:
+
+ * Unambiguous definition of the meaning of information separate from its representation for transmission or storage
+ * Ready translation of JADN models to widely-used format such as JSON Schema and XML Schema that can then be used with common tooling for those formats
+ * Serialization rules for JSON and CBOR, easily extensible to other representations
+ * Conversion of representation between formats that preserves the underlying meaning
+ * Concise, readable format that accurately represents the information model and is readily translatable
+
+> _**TO-DO:** Update the music library information model to better support this
+> introductory example and update the excerpts here_
+
+An excerpt from the Digital Music Library example presented in full 
+in [Section 3.3.1](#331-digital-music-library)
+helps illustrate. Each music track in the library is described by a collection of metadata
+(present here in JADN Interface Definition Language [JIDL] format):
+
+```
+Track-Info = Record                          // information about the individual audio tracks
+   1 track_number     Integer                // track sequence number
+   2 title            String                 // track title
+   3 length           Integer{1..*}          // length of track in seconds; 
+                                             // anticipated user display is mm:ss; minimum length is 1 second
+   4 audio_format     Audio-Format           // format of the digital audio (enumeration)
+   5 featured_artist  Artist unique [0..*]   // optional notable guest performers 
+   6 track_art        Image optional         // each track can have optionally have individual artwork
+   7 genre            Genre                  // musical genre of the track (enumeration)
+```
+
+The JIDL presentation is concise and easily understood. Each element is defined
+by its meaning (e.g., the track number is an _integer_, not a string containing
+only digits). The details of `Artist`, `Image`, and other types referenced in
+this metadata record are defined in other similar structures. The JADN from which the
+JIDL is generated can be readily translated into JSON or XML schema forms for
+use with existing tooling for those formats but the readability of the JIDL format simplifies
+development, examination, and refinement of the model.
+
+> NOTE: Comments have been omitted from the JSON and XML schemas below for space reasons.
+
+**Track-Info in JSON Schema**
+```json
+    "Track-Info": {
+      "title": "Track Info",
+      "type": "object",
+      "additionalProperties": false,
+      "required": [
+        "track_number",
+        "title",
+        "length",
+        "audio_format",
+        "genre"
+      ],
+      "maxProperties": 100,
+      "properties": {
+        "track_number": {
+          "type": "integer",
+        },
+        "title": {
+          "type": "string",
+          "maxLength": 255
+        },
+        "length": {
+          "type": "integer",
+          "minimum": 1
+        },
+        "audio_format": {
+          "$ref": "#/definitions/Audio-Format",
+        },
+        "featured_artist": {
+          "type": "array",
+          "uniqueItems": true,
+          "minItems": 0,
+          "items": {
+            "$ref": "#/definitions/Artist",
+          }
+        },
+        "track_art": {
+          "$ref": "#/definitions/Image",
+        },
+        "genre": {
+          "$ref": "#/definitions/Genre",
+        }
+      }
+    },
+```
+<br><br>
+**Track-Info in XML Schema***
+```xml
+	<xs:complexType name="Track-Info">
+		<xs:sequence>
+			<xs:element id="track_info_track_number" name="track_number" type="jadn:Integer" minOccurs="1" />
+			<xs:element id="track_info_title" name="title" type="jadn:String" />
+			<xs:element id="track_info_length" name="length">
+				<xs:simpleType>
+					<xs:restriction base="jadn:Integer">
+						<xs:minInclusive value="1" />
+					</xs:restriction>
+				</xs:simpleType>
+			</xs:element>
+			<xs:element id="track_info_audio_format" name="audio_format" type="Audio-Format" />
+			<xs:element id="track_info_featured_artist" name="featured_artist" type="Artist" minOccurs="0" maxOccurs="unbounded" />
+			<xs:element id="track_info_track_art" name="track_art" type="Image" minOccurs="0" />
+			<xs:element id="track_info_genre" name="genre" type="Genre" />
+		</xs:sequence>
+	</xs:complexType>
+```
+
+The following sections examine the meaning of information and the value of
+information models in more detail.
+
 ### 1.1.1 Information Models and Data Models
 
 Internet Engineering Task Force (IETF) [RFC 3444](#rfc3444),
@@ -1044,24 +1155,7 @@ Table 3-2 summarizes the applicability of type options to JADN core types.
 
 ###### Table 3-2 -- Type Option Applicability
 
-|           | Binary | Boolean | Integer | Number | String | Array | ArrayOf | Map | MapOf | Record | Choice | Enumerated |
-|----------:|:------:|:-------:|:-------:|:------:|:------:|:-----:|:-------:|:---:|:-----:|:------:|:------:|:----------:|
-|        id |        |         |         |        |        |       |         |  X  |       |        |   X    |     X      |
-|     vtype |        |         |         |        |        |       |    X    |     |   X   |        |        |            |
-|     ktype |        |         |         |        |        |       |         |     |   X   |        |        |            |
-|      enum |        |         |         |        |        |       |         |     |       |        |        |     X      |
-|   pointer |        |         |         |        |        |       |         |     |       |        |        |     X      |
-|    format |   X    |         |    X    |   X    |   X    |   X   |         |     |       |        |        |            |
-|   pattern |        |         |         |        |   X    |       |         |     |       |        |        |            |
-|      minf |        |         |         |   X    |        |       |         |     |       |        |        |            |
-|      maxf |        |         |         |   X    |        |       |         |     |       |        |        |            |
-|      minv |   X    |         |    X    |        |   X    |   X   |    X    |  X  |   X   |   X    |        |            |
-|      maxv |   X    |         |    X    |        |   X    |   X   |    X    |  X  |   X   |   X    |        |            |
-|    unique |        |         |         |        |        |       |    X    |     |       |        |        |            |
-|       set |        |         |         |        |        |       |    X    |     |       |        |        |            |
-| unordered |        |         |         |        |        |       |    X    |     |       |        |        |            |
-|    extend |        |         |         |        |        |   X   |         |  X  |       |   X    |   X    |     X      |
-|   default |        |         |         |        |        |       |         |     |       |        |        |            |
+![Table 3-2 -- Type Option Applicability](images/table-3-2.png)
 
 #### 3.1.1.3 Item Or Field Definitions
 
@@ -3206,6 +3300,7 @@ The following individuals have participated in the creation of this document and
 | imjadn-v1.0-cn01-wd02.md | 2023-11-07 | David Lemire | Administrative clean-up (PR #78) |
 | imjadn-v1.0-cn01-wd02.md | 2023-11-14 | David Lemire | Update diagrams (PR #81) and text (PR #82) to align w/JADN Spec changes |
 | imjadn-v1.0-cn03.md      | 2023-11-26 | David Lemire | Add example development JADN IM from JSON schema starting point (PR #xx), rename document for next CN version |
+| imjadn-v1.0-cn03.md      | 2023-12-11 | David Lemire | Add "Why JADN?" material in Section 1.1 (PR #88) |
 
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