User requirements support


ESCUDO-CLOUD provides a new approach for supporting users in cloud plan selection.

At the heart of the approach is an expressive and powerful, yet simple and user-friendly, language offering simple constructs enabling users to demand requirements that cloud plans should satisfy, and which can correspond to:

  • Simple conditions (e.g., `provider in {GoGo}’)
  • Disjunction of conditions (e.g., ‘ANY(provider in {Amaron}, location in {EU})’ )
  • Conjunction of conditions (e.g. ‘ALL(provider in {GoGo}, location in {EU})’ ) 
  • Implication among conditions (e.g., ‘IF(provider in {GoGo}) THEN (location in {EU})’ )
  • Exclusion of combinations of conditions (e.g., ‘FORBID(provider in {GoGo}, location in {EU})’ )
  • Satisfaction of at least a subset of conditions (e.g., ‘AT-LEAST(2, {provider in {Ghost}, location in {EU}, encryption in {3DES}})’ )
  • Limitation of combinations of conditions (e.g., ‘AT-MOST (2, {provider in {Ghost}, location in {EU}, encryption in {3DES}})’ )

In addition, users can also express preferences on:

  • attribute values, by prioritizing values an individual attribute can take (e.g., for attribute encryption `AES > DES’)
  • attributes, by assigning weights to attributes (e.g., w(encryption)=2, w(location)=1).

A plan is considered acceptable for a user if it satisfies all the requirements stated by the user. Acceptable plans can then be ranked based on the user’s preferences (ordering plans based on their closeness to the ideal plan reflected by preferences).

The approach provides the base for a brokerage system that evaluates available cloud offers by cloud service providers against user requirements and preferences, and 1) determines which plans are acceptable for the user, 2) ranks them according to the user’s preferences.

 

cloud selection framework

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