who called the stages of development psychosexual stages
Psychosexual development In Freudian psychology, psychosexual development is a central element of the psychoanalytic sexual drive theory, that human beings, from birth, possess an instinctual libido (sexual energy) that develops in five stages. Each stage – the oral, the anal, the phallic, the latent, and the genital – is characterized by the erogenous zone that is the source of the libidinal drive. Sigmund Freud proposed that if the child experienced sexual frustration in relation to any psychosexual developmental stage, he or she would experience anxiety that would persist into adulthood as a neurosis, a functional mental disorder.[1][2]
Systems development life cycle The SDLC adheres to important phases that are essential for developers, such as planning, analysis, design, and implementation, and are explained in the section below. It includes evaluation of present system, information gathering, feasibility study and request approval. A number of SDLC models have been created: waterfall, fountain, spiral, build and fix, rapid prototyping, incremental, synchronize and stabilize. The oldest of these, and the best known, is the waterfall model: a sequence of stages in which the output of each stage becomes the input for the next. These stages can be characterized and divided up in different ways, including the following:[7]