ATOM. The Agent-based Team Organization Methodology (ATOM) is based on a workflow concept that combines bottom-up task negotiation with top-down goal assignment. The management services take the form of agents that perform actions in a workflow from the perceived current situation towards a goal, the desired end-situation. The structure of an agent resembles a control systems feedback loop (see Figure 31), and the actions it places in short-term workflows are delegated to operational resources.
ATOM. The smallest amount of an element which has the properties of that element. The atom consists of a central nucleus containing neutrons and protons, around which electrons move in orbits. atomic number The number of protons in the atomic nucleus , and hence the number of electrons on an electrically neutral atom. Determines chemical properties of element. Symbol Z. atomic weight The weight of an atom expressed in atomic mass units (amu). One amu is one twelfth of the mass of a stable atom of carbon, 12C. attenuation The process by which a beam of radiation is reduced in intensity when passing through matter. It is the combination of absorption and scattering processes attenuation coefficient, µ The negative exponent of the exponential equation for the attenuation of radiation passing a distance x through a substance of density . A fraction µdx of the radiation beam is removed in passing through a thin layer of thickness dx. If dx is expressed as a length, then µ is the linear attenuation coefficient, usually tabulated in units of cm-1. If dx is expressed as a mass per unit area, then the mass attenuation coefficient µ/ is used, tabulated in units of cm2.g-1. Auger electron Electron emitted from the atom, after a nuclear transformation by electron capture or internal conversion leaves a vacancy in an electron shell. Some of the resulting characteristic x-rays (see below) impart their energy to orbital electrons which are emitted instead. Auger electrons are numerous and low energy. background radiation Radiation from the natural environment, including cosmic rays and radiation from the naturally radioactive elements, both outside and inside the bodies of humans and animals. xxxxxxxxx (Bq) The SI unit of activity, equal to one nuclear transformation per second. beta particles (or beta rays) A particle with an electric charge of + or - 1, emitted from a nucleus during radioactive decay. A negatively charged beta particle is identical to an electron. A positively charged beta particle is called a positron. Beta particles are easily stopped by a thin sheet of metal or plastic. bioassay The collection and analysis of samples of tissue and body fluids to determine the amount of radioactive material in the body. biological half life The time required for the amount of a substance in an organ, tissue or the whole body to be reduced by half through physiological processes of elimination. Does not include reduction through radioactive decay. Bremsstrahlung Electroma...
