Task Scheduling for Multiunit Parallel Test Using Mixed-Integer Linear Programming

Table 2

Parameters and variables used to formulate the optimal task scheduling problem.

Symbols	Description
R	is a set of various test resources, where I is the number of test resources
N	N is the total number of UUTs to be tested
T	; K is the number of test tasks for all UUTs, and represents the kth test task in all tasks
	is the set of test tasks for UUTn, Kn is the number of test tasks for UUTn, and represents the kth test task for UUTn
K	is the total number of test tasks for all UUTs
	Test time vector , and represents the time needed for test k
A	K × I task-resource dependency matrix; the (k ×i)th element if test k needs resource I, otherwise
	Task start time vector , and is a continuous variable that represents the start time of test k
y	K × K task sequence matrix; the (k1 × k2)th element if there is a technological sequence between tk1 and tk2, which means tk1 finishes before test tk1 begins, otherwise . y^0 is the prerequisite technological task sequence, which is defined by the test flowchart
x	K × J matrix; the (k × j)th element if the kth test task is assigned to thread j, otherwise . J is the total number of test threads