The specification of XML and technologies concerned with XML are now being discussed by W3C (World Wide Web Consortium). XML consists of the following three components.
・XML declaration
The XML declaration specifies the version of XML and the character code being used, An example of this is as follows:
・DTD (Document Type Definition)
DTD specifies the tag definition used for the XML instance to mark up a document.
・XML instance
The XML instance is the content of the XML document. It is referred to as the logical structure of the document, as well.
The markup language is intended to describe not only the content of the document but also the structure of the document. It uses "tags" to describe the document structure. The document is expressed by the set of elements which have a hierarchical structure in XML. The content is written between the start-tag and the end-tag of the element. The syntax of the element is as follows:
For example, the following is part of the XML instance which represents the title of the document.
In this example, the start-tag is "<title>", the content of the element is "Minutes of meeting" and the end-tag is "</title>". The basic structure of the DTD which specifies the tag is as follows:
The application using XML is generally built in the following steps:
Step 1: Definition of DTD
In the first step, the DTD which is used by the sender of the data (i.e. www server) as well as by the receiver of the data (i.e. client) is defined.
Step 2: Program on the server
This program operates on the server to make the XML instance. Various forms of the program can be considered depending on the application. The simplest way is to make the XML instance using the text editor directly. Another way is to make the XML instance by modifying the template that had been prepared beforehand. The most desirable way is to make the XML instance using a program which automatically generates the XML data using the data retrieved from the database.
Step 3: Program on the client
This program operates on the client to process the XML instance. In the same manner as in the case of the server, various types of this program can be considered depending on the application. The program can be easily prepared because the data structure can be easily retrieved from the XML instance using the XML parser.
3.2 Identification of the propeller data
Generally, it is not easy to select which data among the propeller design data is to be transmitted. However, the type of data can be restricted to that connected with the technical Rules of the classification society in this experiment because the aim of this experiment is to investigate the procedure of the plan approval process mentioned in 2.2. Therefore, the data to be transmitted has been decided with reference to the data stored in the machinery particulars database. The result is as follows:
1. Group A: common items
Manufacturer of propeller
2. Group B: propeller particulars
Kind of propeller, Fit method of propeller, Material of propeller, Number of blades, Diameter of propeller, Pitch of 0.7R, Boss ratio of propeller, Expanded aria ratio of propeller, Rake at tip of blade, Imaginary thickness of blade at propeller shaft centerline, Skew angle, Specified strength of propeller
3. Group C: ship particulars
Code of ice strengthening, Code of high speed craft, Engine output, Revolution of propeller, Breadth, Depth, Load draught, Block coefficient of ship
4. Group D: required values
Required thickness at 0.25R/required thickness at 0.35R, Required thickness at 0. 6R, Required thickness at root, Required thickness at 0.7R, Required thickness at 0.8R, Required thickness at 0.9R, Required thickness at tip
5. Group E: design data
Pitch of 0.25R/pitch of 0.35R, Blade width of 0.25R/Blade width of 0.35R, Blade thickness of 0.25R/Blade thickness of 0.35R, Pitch of 0.6R, Blade width of 0.6R, Blade thickness of 0.6R, Fillet radius of root, Blade thickness of 0.7R, Blade thickness of 0.8R, Blade thickness of 0.9R, Blade thickness of tip
6. Group F: force fitting of propeller
Kind of engine, Material code (A) of propeller shaft, Material code (B) of propeller shaft, Taper at the propeller shaft corn part, Mean radius of taper shaft, Mean radius of boss, Mean hollow radius of taper shaft, One half length of boss, Contact area of shaft and boss, Torsional vibratory torque, Rotational speed of resonant critical, Rate of R1 to R0, Rate of R2 to R0, Force pressure, KE, Value 1 in equation of KC, Value 2 in equation of KC, Value 1 in equation of L1 (minimum required travel of boss), Value 2 in equation of L1, Value 3 in equation of L1, Value in equation of L2 (maximum required travel of boss).
