attribute_sim_dep       Simulate the Attributes with the Assumption of
                        Dependent Attributes
attribute_sim_ind       Simulate the Attributes with the Assumption of
                        Independent Attributes
demand_sim              Simulate the demand for new products
npd_data_sim            Simulate the demand and attributes for new
                        products
npdsim_bass             Calculate the Bass probability
shape_sim               Generate the shape of demand
shape_sim_bass          Generate generic Bass shapes
shape_sim_ig            Generate generic shapes for the introduction
                        and growth phases
shape_sim_random        Generate random (Bass, Trapezoidal or
                        Triangular) shapes
shape_sim_trapezoid     Generate trapezoidal shapes
shape_sim_triangle      Generate triangular shapes
