REVIEW OF LITERATURE
Shift Work Shift work is an employment practice designed to make use of, or provide service across, all 24 hours of the clock each day of the week. The practice typically sees the day divided into "shifts", set periods of time during which different groups of workers take up their posts. The term "shift work" includes both long-term night shifts and work schedules in which employees change or rotate shifts. Once considered a manufacturing issue, shift work occurs today in many industries and fields. Law enforcement, military, security, healthcare, retail, restaurants, hospitality, service stations, grocery stores, transportation, fire stations, convenience stores, customer service call centres, newspapers, media, and any
…show more content…
As a firefly’s attractiveness is proportional to the light intensity seen by adjacent fireflies, we can now define the variation of attractiveness β with the distance r by β = β_0 e^(-γr^2 ) where β_(0 )is the attractiveness at r = 0. The movement of a firefly i is attracted to another more attractive firefly j is determined by x_i^(t+1) = x_i^t+β_0 e^(-γr_ij^2 ) (x_j^t-x_i^t )+α_t ϵ_i^t where the second term is due to the attraction. The third term is randomization with α_t being the randomization parameter, and ϵ_i^t is a vector of random numbers drawn from a Gaussian distribution or uniform distribution at time t. If β_0 = 0, it becomes a simple random walk. On the other hand, if γ = 0, it reduces to a variant of particle swarm optimisation. Furthermore, the randomization ϵ_i^t can be extended to other distributions such as L´evy flights. The parameter γ characterizes the variation of attractiveness, and its value is important in determining the speed of convergence and how the algorithm behaves. In practice, γ = O(1) is determined by the characteristic length Г of the system to be optimized. Thus, it typically varies from 0.1 to