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The Changing Nature of Feature Interaction. Luigi Logrippo Université du Québec en Outaouais With thanks to discussion with Tom Gray, Ken Turner, others. FI an outdated problem?. FI research and the FIW conference arose from an immediate and specific technological need
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The Changing Nature of Feature Interaction Luigi Logrippo Université du Québec en Outaouais With thanks to discussion with Tom Gray, Ken Turner, others...
FI an outdated problem? • FI research and the FIW conference arose from an immediate and specific technological need • Dealing with FIs in a very specific telephony architecture (IN) • Much of FI work has been targeted to this need • However researchers have been saying all along that this is a general problem
Will there still be FIs in VoIP? • Consider the following situations: • a telephone ringsback simultaneously free and busy • one can dial a new call when hearing busy • one can get connected to someone in her black list • anyone can dial in to an existing conversation • an event under the same preconditions can give sometimes a result, other times another result • If all this and more should be tolerated in VoIP, then no point looking for FI
The new importance of intentions • Since features are freely programmable in VoIP, then technologically there is no reason to worry about any of the above situations • Some users may want it that way, who knows... • FI must be taken to be undesirable effects of feature composition • What is undesirable depends on user intentions
Intentions, policies and their inconsistencies • Some intentions are explicitly stated, these are the policies • Some are implicit, expectations about system behavior • FI are inconsistencies in collections of • User policies • User intentions • That can occur in specific situations
Resolution in context (Tom Gray) • Application will be 'embedded' in the larger enterprise or social context. • Resolution must be done within the rules or expectations of that context • a call from a boss is important • a cold call from a saleman is not • for a lawyer, a call from a judge's office requires immediate attention • The designer must be aware of the sociological expectations that surround the human endeavor that application is supporting • This requires much customization
The world of web servicesFIs galore with a vengeance! • A phone can ring wrongly without much harm, but the purchase of an expensive item can’t be cancelled as easily! • Forwarding loops: much worse in effects and prevention! • E.g. loops of subcontracts can lead to disastrous economic effects • Interactions in contracts: policies of different users clash, thus making certain contracts impossible, perhaps for futile reasons... • Users must be made aware of clashes that may have certain types of consequences, must be hidden other types of clashes • Security gaps in access control can be the result of interactions