Qualitative and Quantitative Representing and Reasoning for Goals Satisfiability

Satisfiability representation and reasoning are important issues in goal-oriented requirements engineering.According to the uncertainty of subjective cognition during abstract qualitative concepts from quantitative universal set,this paper proposes a representation model based on the cloud model for goals satisfiability.The proposed model integrates randomness and fuzziness of subjective perception of goals satisfiability.It has qualitative semantic clarity as well as quantitative accuracy of goals satisfiability.On the basis of the model,the paper presents a reasoning approach based on the core idea of ordered weighted aggregation operators.This approach deduces satisfiability of parent goals between the minimal and maximal satisfiability of sub-goals which reflects the pecularity of human thinking and avoids absolute reasoning results based on pure logic "and" and "or".The main characteristics are analyzed through theorem proving and comparison experiments.Finally,conclusions are drawn and research directions are pointed out.