- 行业: Printing & publishing
- Number of terms: 178089
- Number of blossaries: 0
- Company Profile:
McGraw Hill Financial, Inc. is an American publicly traded corporation headquartered in Rockefeller Center in New York City. Its primary areas of business are financial, publishing, and business services.
A computer system in which computational and data resources are made available simultaneously to a number of users. Users access the system through terminal devices, normally on an interactive or conversational basis. A multiaccess computer system may consist of only a single central processor connected directly to a number of terminals (that is, a star configuration), or it may consist of a number of processing systems which are distributed and interconnected with each other as well as with the user terminals.
Industry:Science
A computer virus is a computer program that is designed to replicate itself from file to file or from disk to disk. Viruses comprise the same basic instructions and program logic that constitute application programs, such as word processors, games, or spreadsheets. However, the computer virus is designed to spread itself without the user's knowledge, while normal applications are designed to provide a useful function. Computer viruses are written by people, and they must be intentionally designed and programmed to self-replicate. However, once a computer virus has been introduced into a system, it is capable of spreading without the aid of a human.
Industry:Science
A computer which, among existing general-purpose computers at any given time, is superlative, often in several senses: highest computation rate, largest memory, or highest cost. Predominantly, the term refers to the fastest “number crunchers,” that is, machines designed to perform numerical calculations at the highest speed that the latest electronic device technology and the state of the art of computer architecture allow.
Industry:Science
A computer-programming methodology that focuses on data items rather than processes. Traditional software development models assume a top-down approach. A functional description of a system is produced and then refined until a running implementation is achieved. The refinement process breaks each system function down into subfunctions which combine to implement the higher-level function. The emphasis of the approach is on the transformation of inputs to outputs. Data structures (and file structures) are proposed and evaluated based on how well they support the functional models.
Industry:Science
A concept developed by the Italian economist Vilfredo Pareto (sometimes called the 20-80 rule) describing the frequency distribution of an empirical relationship fitting the skewed concentration of a variate-values pattern. The phenomenon wherein a small percentage of a population accounts for a large percentage of a particular characteristic of that population is an example of Pareto's law. When the data are plotted graphically, the result is called a maldistribution curve. To take a specific case, an analysis of a manufacturer's inventory might reveal that less than 15% of the component part items account for over 90% of the total annual usage value. Other analyses may show that a small percentage of suppliers account for most of the late or substandard deliveries; a few engineers get most of the patents; a few employees are responsible for most of the quality rejects, errors, accidents, absences, thefts, and so on.
Industry:Science
A concept in product design, sometimes referred to as ease of use or user-friendliness, that is related directly to the quality of the product and indirectly to the productivity of the work force. Customer surveys show that product quality is broken down into six components (in descending order of importance): reliability, durability, ease of maintenance, usability, trusted or brand name, and price. Ease of maintenance and usability both relate to product usability. Reliability also has a component of usability to it. If a product is too difficult to use and thus appears not to work properly, the customer may think that it has malfunctioned. Consequently, the customer may return the product to the store not because it is unreliable but because it does not work the way the customer thinks it should.
Industry:Science
A concept related to the flow of heat from one object or region of space to another. The term refers not only to the senses of hot and cold but to numerical scales and thermometers as well. Fundamental to the concept are the absolute scale and absolute zero and the relation of absolute temperatures to atomic and molecular motions.
Industry:Science
A concept which can predict or explain the stereochemistry of certain types of reactions in organic chemistry. It is also described as the conservation of orbital symmetry, and is named for its developers, R. B. Woodward and Roald Hoffmann. The rule applies to a limited group of reactions, called pericyclic, which are characterized by being more or less concerted (that is, one-step, without a distinct intermediate between reactants and products) and having a cyclic arrangement of the reacting atoms of the molecule in the transition state. Most pericyclic reactions fall into one of three major classes, examples of which will illustrate the use of the rule.
Industry:Science
A concrete, metal, or timber structure that is relatively high for its length and width. Towers are constructed for many purposes, including the support of electric power transmission lines, radio and television antennas, and rockets and missiles prior to launching.
Industry:Science
A condition caused by the thickening of ligaments and tendon sheaths at the wrist, with consequent compression of the median nerve at the palm. Affected individuals report numbness, tingling, and pain in the hand; the discomfort often becomes worse at night or after use of the hand. A physical examination of the injured hand during the early stages of the syndrome often reveals no abnormality. With more severe nerve compression, the individual experiences sensory loss over some or all of the digits innervated by the median nerve (thumb, index finger, middle finger, and ring finger) and weakness of thumb movement.
Industry:Science
