tailieunhanh - Building Web Reputation Systems- P6

Building Web Reputation Systems- P6:Today’s Web is the product of over a billion hands and minds. Around the clock and around the globe, people are pumping out contributions small and large: full-length features on Vimeo, video shorts on YouTube, comments on Blogger, discussions on Yahoo! Groups, and tagged-and-titled bookmarks. User-generated content and robust crowd participation have become the hallmarks of Web . | model is activated by a specific input arriving as a message to the model. Input gets the ball rolling. Based on the requirements of custom reputation processes there can be many different forms of input but a few basic input patterns provide the common basic structure. Typical inputs. Normally every message to a reputation process must contain several items the source the target and an input value. Often the contextual claim name and other values such as a timestamp and a reputation process ID also are required for the reputation system to initialize calculate and store the required state. Reputation statements as input. Our diagramming convention shows reputation statements as inputs. That s not always strictly accurate it s just shorthand for the common method in which the application creates a reputation statement and passes a message containing the statement s context source claim and target to the model. Don t confuse this notational convention with the case when a reputation statement is the target of an input message which is always represented as a embedded miniature version of the target reputation statement. See Reputation Targets What or Who Is the Focus of a Claim on page 25. Periodic inputs. Sometimes reputation models are activated on the basis of an input that s not reputation based such as a timer that will perform an external data transform. At present this grammar provides no explicit mechanism for reputation models to spontaneously wake up and begin executing and this has an effect on mechanisms such as those detailed in Freshness and decay on page 63. So far in our experience spontaneous reputation model activation is not necessary and keeping this constraint out has simplified high-performance implementations. However there is no particular universal requirement for this limitation. Output Many reputation models terminate without explicitly returning a value to the application at all. Instead they store the output asynchronously in reputation