Optimization techniques are used to find the best solution among a set of feasible alternatives that satisfies the specified constraints and objectives. In engineering design and decision making, optimization techniques are widely used to improve performance, reduce cost, and enhance efficiency. Some popular optimization techniques used in engineering design and decision making are:

**Linear Programming (LP):**LP is a mathematical technique used to optimize a linear objective function subject to linear constraints. LP is used to solve problems with a large number of variables and constraints, such as transportation planning, resource allocation, and production scheduling.**Nonlinear Programming (NLP):**NLP is a technique used to optimize nonlinear objective functions subject to nonlinear constraints. NLP is used in problems where the objective function or constraints are nonlinear, such as design optimization, portfolio optimization, and parameter estimation.**Multi-objective Optimization:**Multi-objective optimization is a technique used to optimize multiple objectives simultaneously subject to constraints. Multi-objective optimization is used in problems where there are conflicting objectives, such as minimizing cost while maximizing performance, or maximizing reliability while minimizing weight.**Genetic Algorithms (GA):**GA is a search algorithm inspired by the principles of evolution and natural selection. GA is used to find the optimal solution by generating a population of candidate solutions and applying genetic operators such as mutation, crossover, and selection to evolve the population towards better solutions. GA is used in problems where the search space is large and complex, such as design optimization, scheduling, and control.**Particle Swarm Optimization (PSO):**PSO is a metaheuristic optimization technique inspired by the social behavior of birds or fish. PSO is used to optimize a problem by iteratively moving a swarm of particles towards the optimal solution. PSO is used in problems where the search space is continuous and high-dimensional, such as engineering design, control, and scheduling.**Simulated Annealing (SA):**SA is a stochastic optimization technique inspired by the physical process of annealing. SA is used to find the global optimum by iteratively perturbing the solution and accepting the perturbation based on a probability function. SA is used in problems where the objective function has many local optima, such as optimization of energy systems, engineering design, and scheduling.

These techniques can be combined and customized to solve specific engineering design and decision-making problems. Choosing the right optimization technique depends on the specific problem, constraints, and objectives.