The principle of XML and its application in the JDF process

JDF provides a mechanism that can control all production processes. JDF's task is to process the information flow from the beginning to the end of the job and to link MIS and production equipment. It is important that JDF can perform both of these tools regardless of the tool used. Tasks. Unlike other live ticket formats, JDF allows you to describe all the processes required to complete production, from job ordering to finished product shipping. Each process is converted into a node. The entire work is described as a tree of nodes. All nodes are grouped together to describe the required products. Each node is defined as input and output.

JDF is an open standard for all semi-automated business and production programs. It is used to implement smooth information exchange between different systems and applications, and it tries to integrate the entire printing and publishing industry, including on-demand printing companies and e-commerce companies. The advantage of JDF is that it can provide a bridge between the various parts of the printing workflow (from customer ordering to production of finished products). It also enables the smooth exchange of information between MIS (Management Information System) and the generation service department, as well as the timely and effective communication of customer opinions and production status.

JDF describes the entire work as a hierarchical network of operations. Nodes are connected by a consumption input and a product output. The output of each node will be the input of further processing in sequence. The final result is that all the output composites will get the desired result. Finished product. JDF embeds individual actions into the macro process, making it part of the overall system structure.

Figure 3 tree structure node breakdown

JDF can be used to handle any size of business, from small jobs to large jobs. JDF can reduce the configuration costs for implementing communication between different provider systems. At the same time it can also help complete every aspect of printed jobs, from manufacturing to transportation.

Sixth, operational processing level
The JDF job consists of a series of nodes that specify the production steps. The nodes are connected by input and output and arranged in a hierarchical tree structure. The nodes describe the final product and different parts of the production, such as the cover and insert in Figure 3. . The tree information contained in the nodes becomes more detailed and accurate. Each child node defines a component of production and has a series of unique features, such as different media, different physical dimensions, or different color requirements. The nodes represent a set of operations required to produce parts of the product. Each node near the tip of the branch represents a separate operation. The child node cover and inserts in the example all have very different requirements. Therefore, the two nodes need to better describe the activity elements in a broad sense, and there are black and white pages and color pages on the inner page. This requires different methods of operation, and further branching is necessary.

Figure 4 JDF tree structure hierarchy

Because the output resources of many JDF nodes are input resources of other nodes at the same time, many nodes do not start working until their resources are all in place, which means that the nodes need to work in a well-defined order. For example, the output resource plate of the plate making process is the input resource required for the next printing process. In the JDF hierarchical tree structure, the upper node represents a higher level and more abstract operation, and the opposite approaching the bottom represents a more detailed and specific operation. The operation. In particular, the nodes near the top of the tree only represent the meaning of the various components of the product. The leaf node provides specific detailed operation instructions for the device.

In this hierarchical structure of node trees, nodes are connected to the service chain by their respective resources. The output resource of one node is the input resource of the next node. This relationship is called resource connection. With a resource connection, you can build a complex business network.

Because the output resources of many JDF nodes are input resources of other nodes at the same time, many nodes do not start working until their resources are all in place, which means that the nodes need to work in a well-defined order. For example, the output resource plate of the plate making process is the input resource required for the next printing process. In the JDF hierarchical tree structure, the upper node represents a higher level and more abstract operation, and the opposite approaching the bottom represents a more detailed and specific operation. The operation. In particular, the nodes near the top of the tree only represent the meaning of the various components of the product. The leaf node provides specific detailed operation instructions for the device.

In this hierarchical structure of node trees, nodes are connected to the service chain by their respective resources. The output resource of one node is the input resource of the next node. This relationship is called resource connection. With a resource connection, you can build a complex business network.

Figure 5 JDF tree/network diagram

The business connection in JDF does not clearly indicate that the nodes do not have abstract schedules and instructions. For example, the color printing node must be before the RIP node, but it is implicitly defined in the exchange of input and output. Business network, all business execution is driven by these compliance, a resource compliance may contain multiple business path scripts, MIS uses the relevant local constraints to determine the appropriate solution, so MIS write JDF job proxy server It should also be consistent with these local constraints, such as the predominance of prepress software, prepress equipment and printing distance, print load and delivery time, etc. should be taken into account. All these factors come together to describe the production process. To help the proxy server define the workflow, JDF provides four different types of basic service routing mechanisms that can be combined in any combination:

· Continuous processing (overall resources are continuous production and consumption, the simplest business chain)

· Overlap processing (simultaneous production and consumption of resources)

Parallel processing (resource decomposition control and sharing)

Iterative processing (recursive loop iterations to generate resources)

Seventh, MIS integration

To co-ordinate the equipment of different manufacturers requires a great deal of effort. Although the XML language has the ability to encode multiple languages, it is not completely available. Moreover, the biggest and most important obstacle in the printing workflow is that there is a big problem in communication between the management information system (MIS) responsible for planning and controlling work and the production service system responsible for the operation. In other words, there is no automatic, coordinated, effective two-way communication between these two aspects. All the data listed in the plan, arrangement, processing results, work status and job tracking must be passed from the production department to the MIS. MIS can process the information provision instructions.

Figure 6

JDF provides a mechanism for controlling and tracking jobs for natural production systems, and provides information delivery services between MIS and production. During the execution of jobs, the results of each processing process are stored for better tracking. The system defines a series of standard information, information formats, and equipment implementation agreements. It also provides a range of information. The minimum acceptance amount is zero. In the absence of information selection, the controller must check the JDF to determine the outcome of the processing. In addition to information capacity, JDF includes different audit records for each process, which provides details of the processing plan and actual results. Most devices will choose to support different levels of information capacity.

The equipment must support the command function. If the equipment selects the command function, the controller can issue instructions to interrupt the current work, restart a job or change the priority of the work. In addition to communication, JDF can also support the controller to collect each process. The execution data is transmitted to the tracking system for use by a job accounting system.
In addition, the entire job information can be transmitted to a job accounting system. The system then checks the audit record to determine the cost of the entire job. Each individual project manager selects one or more operations to complete each individual job. At the beginning of the first version, JDF was unrelated to the equipment provider. This ensures that all providers can use the JDF development system, and that no provider is at a disadvantage in the competition.

JDF defines a message architecture that includes message formats, semantics, and communication protocols. The JDF driver uses this architecture to communicate information with systems that control production equipment. System providers also have greater flexibility in choosing message mechanisms. JDF provides a good opportunity for MIS integration.

Eight, JDF library and simulator

In cooperation with Wuppertal University and Heidelberg, the Java class library for writing and interpreting JDF has been implemented. The library will be announced by the CIP4 Alliance as a common resource repository for members of the CIP4 so that the open source library-based agents, controllers, and equipment can be effectively developed.

Figure 7

At the top of the library there is a Java-based simulation tool used to model the JDF workflow. This tool was also developed by the Wuppertal University. Users can use the WEB interface to put the JDF into the hot folder as the output information of the simulator and process the information. Through JDF to different production resources, these simulation resources can be processed on a single computer or as a distributed system (based on TCP/IP). When the simulator runs discrete events, the generated production status, error information, etc. will be used as work messages. Is sent to the controller, in the future even "real" JDF controller is integrated into the simulation environment for testing.

Figure 8

In this way, advanced methods for testing new agents, new controllers, and new devices will be implemented so that early testing does not require a real production environment.

Nine, Conclusions and Prospects

XML can realize independent computer system inter-funding