Why use waterfall model to develop a system in a certain army?

We see that more and more manufacturers take "people-oriented" and "ergonomic design" as the characteristics of their products for advertising, especially computers, furniture and other products that are in direct contact with the human body. In fact, ergonomics is an engineering science to solve such problems by making the design of machines and working and living environments suitable for people's physiological and psychological characteristics and making people work and live in comfortable and convenient conditions. Here we introduce the origin, application and development prospect of ergonomics. 1. The design of telephone is the beginning of ergonomics. When it comes to ergonomics, we should first introduce a person-Henry? Dreves (1903- 1972) is the founder of ergonomics. Dreves started as a stage designer, and 1929 set up its own industrial design office. He started to cooperate with Bell Company on 1930. Dreves insists that the design of industrial products should consider highly comfortable functionality and puts forward the design principle of "from the inside out". Bell Company initially thought that this way would make the telephone look too mechanized, but after his repeated arguments, the company agreed to design the telephone in his way. Since then, Dreyfus has forged an indissoluble bond with Bell Telephone Company for life. He is the most important designer who has influenced the modern telephone form. As we all know, Bell has been the largest telephone company and telephone manufacturer in the United States for a long time since Mr. Bell invented the telephone, and was basically not threatened by competition. Therefore, Dreves can pay less attention to the competitive effect of design in the market and pay more attention to the perfect functional design of telephone. Bell introduced the transverse discharge microphone for the first time in 1927, which changed the design of the longitudinal discharge microphone in the past. In 1937, Dreves put forward the design of combining the receiver and microphone into one. Although the model 300 phone designed by Dreves looks very old-fashioned today, this design is the first time to reduce the telephone that was divided into two parts in the past into a whole. Due to the success of this design, Bell signed a long-term design consulting contract with Dreves. In the early 1950s, the materials used to make telephones changed from metal to plastic, thus basically determining the modeling basis of modern telephones. By the end of 1950s, Dreves had designed 100 kinds of telephones. As a result, Dreyfus's telephone has entered thousands of households in the United States and the world and has become the basic facility of modern families. Drevis's other achievements in ergonomics are that since 1955, he has been working for John F. In a series of agricultural machinery developed by Deere Company, these designs are centered on establishing comfortable driving and working conditions based on ergonomics calculation and characterized by simple appearance, among which the design of parts related to human body meets the basic requirements of human body comfort, which is a very important progress and development of industrial design. Dreves's design belief is that the design must meet the basic requirements of the human body, and he thinks that the machine that adapts to people is the most efficient machine. After years of research, he summed up the data about the human body and the proportion and function of the human body. 1955 published the monograph "designing people" and collected a lot of ergonomics data. 196 1 year, he published the book "human scale", which laid the foundation in the field of industrial design, and Drevis became the first one. 2. The research direction of ergonomics has now developed into a multidisciplinary industrial design discipline. The core problem of the research is the coordination among people, machines and environment in different operations. Research methods and evaluation methods involve psychology, physiology, medicine, anthropometry, aesthetics and engineering technology. The purpose of the research is to guide the design and transformation of working instruments, working methods and working environment through the application of knowledge in various disciplines, so as to make the operation efficient and safe. Ergonomics originated from different disciplines and fields, and it is also facing the research and application in a wider field, because the man-machine environment problem is a universal problem in human production and life. The differences between disciplines and producing areas have also caused the long-term diversified coexistence of discipline names. There are mainly ergonomics (European formulation) and ergonomics (American formulation) in English, while there are also expressions such as ergonomics, ergonomics and ergonomics in Chinese. In China, "Ergonomics" is generally regarded as the standard name of this subject, while "Ergonomics" is more common. In a word, the study of man and ergonomics and man-machine relationship is the core content of this subject. The research of various branches of ergonomics made a breakthrough during the Second World War, because the development of complex weapons in the war suddenly aggravated the problem of man-machine coordination. For example, air combat and fighter planes put forward requirements for pilots' physical quality and intelligence, making it increasingly difficult to select and train personnel, making it necessary to add consideration to human factors in the design of aircraft instrument display, control tools and pilot seats, thus promoting the rapid development of related technologies and methods. Ergonomics has a wide range of applications, involving almost all aspects of human work and life. The main application directions are as follows: (1) Human working behavior anatomy and anthropometry; Work accidents, health and safety include anthropometry and workspace design; Research on posture and biomechanical load: bone and muscle management related to work; Healthy ergonomics; Safety culture and safety management; Safety culture evaluation and improvement (2) cognitive ergonomics and complex tasks; Study on cognitive skills and decision-making of environmental ergonomics: analysis of environmental conditions and factors; Work environment ergonomics (3) computer ergonomics; Display and control layout design; Man-machine interface design and evaluation software ergonomics: the design and layout of computer products and peripherals; Ergonomics research on office environment: man-machine interface form (4) Expert demonstration: multi-working environment; Investigation and research on expert argumentation of human reliability: legal ergonomics; Cause of injury; Human error and reliability research; Litigation support; (5) Industrial design and application of medical equipment; Study on the design and comfort of seating: classification and selection of furniture; Workload analysis; (6) Human resource management and ergonomics; Working procedures; Man-machine rules and practices; Manual workload (7) office ergonomics and design; Medical ergonomics office and office equipment design; Psychophysiology; Standards of conduct; Systematic analysis of three-dimensional human models (8); Product design and customers; Military system; Organizational psychology; Product reliability and safety; Clothing ergonomics; Three-dimensional human model; Army ergonomics: automatic speech recognition; (9) Ergonomics strategy; Socio-technical system; Violence assessment and motivation; (10) usability evaluation and testing; Usability audit; Usability assessment; Usability training; Testing and verification; Simulation and testing; Simulation study; Simulation and prototype; 3. Application Direction of Ergonomics Ergonomics as an engineering application discipline, the basic research object is people's work, often aiming at specific practical problems. Many of these truths are often very simple after understanding, but they are often difficult to find or ignored before understanding. The most common example is that teenagers' improper learning posture can lead to myopia. In order to prevent hunchback and myopia when writing, people have designed various posture correction devices to limit the bow and waist, so that students can keep a correct sitting posture when writing. These instruments may not satisfy students. The key to the problem is that people's eyes are forward on their faces, which is suitable for positive observation, while reading and writing require their faces to tilt downward. At this time, straightening their spine will inevitably lead to an increase in the bending angle of their necks. If you want to straighten your chest and neck, you have to roll your eyes down hard. In fact, a moderately hunched posture naturally formed in homework, in which the distortion of this angle is shared by the spine, neck and eyes, may be a posture more suitable for people's physiological characteristics. The reasonable solution to this problem is to make the desktop have a proper slope, and the chair seat should be designed as a waterfall front edge, so the corresponding table and chair design is the most important. Similar problems also appear in the posture of operating the computer. Under normal circumstances, the operator often hangs his arm forward to operate the keyboard and mouse. The arm suspension causes the static fatigue of the shoulder and neck, which brings inconvenience to the operator to lean back against the chair backrest. When the operator leaves the backrest and his arm is suspended, all the weight needs to be borne by the spine. The result is either back fatigue and pain, or the lumbar muscles give up the posture of sitting up straight and hunching over, or the wrist leans against the edge of the table, leading to carpal tunnel syndrome. Another example is the bus seat, or the upper part of the boss's chair backrest, which has a bulging convex hull. From the design point of view, this convex hull was originally used to cushion the concave part of the neck and make people's head and neck more comfortable. For most people in China, this kind of convex hull is often placed on the back of the head, which makes them have to bend their heads slightly when leaning back in their chairs. The problem arises because the design of these seats is imported from abroad, while the manufacturers completely copy the size. Because China people are smaller than westerners, this is the result. With the advent of the information society, computer human-computer interface has entered the era of communication and intelligent interaction, and natural human-computer interaction means such as voice-based applications and pens have begun to enter the practical stage. Such as computer touch screen, photoelectric pen input device, to achieve a natural and comfortable writing feel, similar to the feeling of moving a pen on paper. The pen can replace the mouse, and the user can complete the computer operation by tapping the touch screen with the computer pen; The pen can also replace the keyboard and write directly on the display screen; In addition, the problem of Chinese character recognition in Lian Bi with distorted Chinese characters has also been solved. There is also IBM's speech recognition technology, especially the Chinese speech recognition technology product Via Voice, which realizes "you can recognize it by looking at the computer". In this way, ordinary people without professional training can also communicate with you on the computer.