Empirical Study of Homogeneous and Heterogeneous Ensemble Models for Software Development Effort Estimation

Table 2

Investigated homogeneous and heterogeneous ensemble models.

Ensemble type	Base learner(s)	Combination type	Combination rule	Abbreviation
Homogeneous	MLP	Linear	Averaging	HM-MLP-[Avg]
			Weighted averaging	HM-MLP-[WtAvg]
		Nonlinear	MLP	HM-MLP-[MLP]
			SVR	HM-MLP-[SVR]
			FIS-FCM	HM-MLP-[FIS-FCM]
			FIS-SC	HM-MLP-[FIS-SC]
			ANFIS-FCM	HM-MLP-[ANFIS-FCM]
			ANFIS-SC	HM-MLP-[ANFIS-SC]
	SVR	Linear	Averaging	HM-SVR-[Avg]
			Weighted averaging	HM-SVR-[WtAvg]
		Nonlinear	MLP	HM-SVR-[MLP]
			SVR	HM-SVR-[SVR]
			FIS-FCM	HM-SVR-[FIS-FCM]
			FIS-SC	HM-SVR-[FIS-SC]
			ANFIS-FCM	HM-SVR-[ANFIS-FCM]
			ANFIS-SC	HM-SVR-[ANFIS-SC]
	ANFIS	Linear	Averaging	HM-ANFIS-[Avg]
			Weighted averaging	HM-ANFIS-[WtAvg]
		Nonlinear	MLP	HM-ANFIS-[MLP]
			SVR	HM-ANFIS-[SVR]
			FIS-FCM	HM-ANFIS-[FIS-FCM]
			FIS-SC	HM-ANFIS-[FIS-SC]
			ANFIS-FCM	HM-ANFIS-[ANFIS-FCM]
			ANFIS-SC	HM-ANFIS-[ANFIS-SC]
Heterogeneous	MLP, SVR, and ANFIS	Linear	Averaging	HT-(MLP, SVR, ANFIS)-[Avg]
			Weighted averaging	HT-(MLP, SVR, ANFIS)-[WtAvg]
		Nonlinear	MLP	HT-(MLP, SVR, ANFIS)-[MLP]
			SVR	HT-(MLP, SVR, ANFIS)-[SVR]
			FIS-FCM	HT-(MLP, SVR, ANFIS)-[FIS-FCM]
			FIS-SC	HT-(MLP, SVR, ANFIS)-[FIS-SC]
			ANFIS-FCM	HT-(MLP, SVR, ANFIS)-[ANFIS-FCM]
			ANFIS-SC	HT-(MLP, SVR, ANFIS)-[ANFIS-SC]