How to Identify Boundary Conditions with Contrasty Metric?

Abstract

The boundary conditions (BCs) have shown great potential in requirements engineering because a BC captures the particular combination of circumstances, i.e., divergence, in which the goals of the requirement cannot be satisfied as a whole. Existing researches have attempted to automatically identify lots of BCs. Unfortunately, a large number of identified BCs make assessing and resolving divergences expensive. Existing methods adopt a coarse-grained metric, generality, to filter out less general BCs. However, the results still retain a large number of redundant BCs since a general BC potentially captures redundant circumstances that do not lead to a divergence. Furthermore, the likelihood of BC can be misled by redundant BCs resulting in costly repeatedly assessing and resolving divergences.In this paper, we present a fine-grained metric to filter out the redundant BCs. We first introduce the concept of contrasty of BC. Intuitively, if two BCs are contrastive, they capture different divergences. We argue that a set of contrastive BCs should be recommended to engineers, rather than a set of general BCs that potentially only indicates the same divergence. Then we design a post-processing framework (P P F c ) to produce a set of contrastive BCs after identifying BCs. Experimental results show that the contrasty metric dramatically reduces the number of BCs recommended to engineers. Results also demonstrate that lots of BCs identified by the state-of-the-art method are redundant in most cases. Besides, to improve efficiency, we propose a joint framework (J F c ) to interleave assessing based on the contrasty metric with identifying BCs. The primary intuition behind J F c is that it considers the search bias toward contrastive BCs during

Identifying Boundary Conditions with the Syntax and Semantic Information of Goals

“…For requirements engineers, it is more useful to assess the most general BCs to detect the cause of divergence, rather than assessing the less general ones that capture only partial situations. Definition 4 (Witness, Contrasty Metric [26]). Let 𝑓 be an LTL formula and 𝜙 a BC of the given scene 𝑆. 𝑓 is a witness of 𝜙 iff 𝜙 ∧ ¬𝑓 is not a BC of 𝑆.…”

“…For two BCs that are witnesses to each other, it is always better to choose the BC with the shorter formula length, as the conflict analysis would become easier. Compared to the generality metric, the contrasty metric can reduce more BCs [26], so that the requirement engineers can resolve the divergence more efficiently.…”

“…We compare and evaluate our method on the 15 different cases introduced in [6]. We compare our method with JFc (Joint framework to interleave filtering based on the contrast metric) proposed in [26], which is the state-of-art BC solver. 2 shows the comparison between our Syn-tacBC method and JFc on the 15 requirement cases.…”

“…al. presented the concept of contrastive BCs to reduce the number of redundant BCs generated from the above genetic approach [26]. The motivation comes from that two BCs 𝜑 1 , 𝜑 2 are contrastive if 𝜑 1 ∧ ¬𝜑 2 is not a BC and 𝜑 2 ∧ ¬𝜑 1 is not a BC.…”

“…However, current approaches seems to compute mostly the BCs less helpful, i.e., with the form of 𝜓 . Even the contrastive BCs computed in [26] cannot avoid such problem. Take the above example again, 𝜓 1 and 𝜓 2 are contrastive BCs, but they are less helpful than ℎ ∧ 𝑚.…”