Calculus has been used in solving many scientific and engineering problems. For optimization problems, however, the differential calculus technique sometimes has a drawback when the objective function is step-wise, discontinuous, or multi-modal, or when decision variables are discrete rather than continuous. Thus, researchers have recently turned their interests into metaheuristic algorithms that have been inspired by natural phenomena such as evolution, animal behavior, or metallic annealing. This book especially focuses on a music-inspired metaheuristic algorithm, harmony search. Interestingly, there exists an analogy between music and optimization: each musical instrument corresponds to each decision variable; musical note corresponds to variable value; and harmony corresponds to solution vector. Just like musicians in Jazz improvisation play notes randomly or based on experiences in order to find fantastic harmony, variables in the harmony search algorithm have random values or previously-memorized good values in order to find optimal solution.

The average lifespan of a house is somewhere around 100 years. During that time it will see many mutations in household composition and related spatial rituals. Designers are therefore faced with the task of giving form to something that is constantly subject to change. Many studies into flexibility focus on the changeable, on movable partitions and variation in the internal layout. The present study takes not the changeable but the permanent as its departure-point. The permanent--i.e. the more durable component of the house or building--constitutes the frame within which change can take place, while the frame defines the generic space, the space in which change can occur.