时间：2011-08-27 23:38来源：蓝天飞行翻译 作者：航空 点击：次
|
Medium Access Control See Time Division Multiple Access. The medium access control is an additional layer between the data link control layer and the physical layer. The purpose of this layer is to allocate the medium to the various users. There are two extremes among the many strategies in which access is allocated. One is the "free-for-all" approach in which each user will transmit, hoping there will be no interference from other users. The other extreme is the "perfectly scheduled" approach in which there is some order in which users send their information over the media. Medium Frequency The set of frequencies between 300 kHz and 3 MHz. Megahertz A unit of frequency equal to 1,000,000 hertz. Memory Psychological construction representing the repository of knowledge held in the brain. The human memory is divided into s Short-term sensory store (SM), sometimes refereed to as the Working Memory (WM) and Long Term Memory (LTM). (Atkinson & Shiffrin, 1968). Mental Abilities The operations of the mind which are the fundamental, basic - and to some degree abstract - capacities and processes of perceiving, thinking, and deciding. Mental model A model representing the relationships and assumptions about a system held in a person's mind. Mental models are often correct in system structure, but frequently draw wrong conclusions about system behaviour. The picture or concept that is formed in the human mind when no other model is available. Mental Picture The actual MP of the situation represents a moment-to-moment snapshot of the actual situation as represented by the brain. It is based on the Mental Model and the actually perceived external cues. A series of Mental Pictures represents the actual Mental Model including the actual parameterisation. Message Unit of transmitted information over the communication facilities. An ASTERIX message is called a Data Block; A communication sent from one location to another and comprising an integral number of fields. Message Assurance The SITA technical acknowledgement used in PETAL to emulate a LACK capability for uplink messages. Message Fields An assigned area of a message containing specified elements of data. Message Format The disposition and structure of the message fields which constitute a message. |
