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Operational Definition
An operational definition specifies concrete, replicable procedures designed to represent a construct. In the words of American psychologist S.S. Stevens (1935), "An operation is the performance which we execute in order to make known a concept." For example, an operational definition of "fear" (the construct) often includes measurable physiologic responses that occur in response to a perceived threat. Thus, "fear" might be operationally defined as specified changes in heart rate, galvanic skin response, pupil dilation, and blood pressure. Overview An operational definition is designed to model or represent a concept or theoretical definition, also known as a construct. Scientists should describe the operations (procedures, actions, or processes) that define the concept with enough specificity such that other investigators can replicate their research. Operational definitions are also used to define system states in terms of a specific, publicly accessible process of preparation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Definition
A definition is a statement of the meaning of a term (a word, phrase, or other set of symbols). Definitions can be classified into two large categories: intensional definitions (which try to give the sense of a term), and extensional definitions (which try to list the objects that a term describes).Lyons, John. "Semantics, vol. I." Cambridge: Cambridge (1977). p.158 and on. Another important category of definitions is the class of ostensive definitions, which convey the meaning of a term by pointing out examples. A term may have many different senses and multiple meanings, and thus require multiple definitions. In mathematics, a definition is used to give a precise meaning to a new term, by describing a condition which unambiguously qualifies what a mathematical term is and is not. Definitions and axioms form the basis on which all of modern mathematics is to be constructed. Basic terminology In modern usage, a definition is something, typically expressed in words, that attac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
West Gate Bridge
The West Gate Bridge is a steel, box girder, cable-stayed bridge in Melbourne, Victoria, Australia, spanning the Yarra River just north of its mouth into Port Phillip. It carries the West Gate Freeway and is a vital link between the inner city (CBD) and Melbourne's western suburbs, with the industrial suburbs in the west, and with the city of Geelong to the south-west. It is part of one of the busiest road corridors in Australia. The high span bridge was built to allow large cargo ships to access the docks in the Yarra River. The main river span is in length, and the height above the water is . The total length of the bridge is . It is the fifth-longest in Australia, the longest being Melbourne's Bolte Bridge at . The West Gate Bridge is twice as long as the Sydney Harbour Bridge and is one of the highest road decks in Australia, clearing the water at , with the Sydney Harbour Bridge clearing the water at . The bridge passes over Westgate Park, a large environmental and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Temperature Scale Of 1990
The International Temperature Scale of 1990 (ITS-90) is an equipment calibration standard specified by the International Committee of Weights and Measures (CIPM) for making measurements on the Kelvin and Celsius temperature scales. It is an approximation of thermodynamic temperature that facilitates the comparability and compatibility of temperature measurements internationally. It defines fourteen calibration points ranging from to ( to ) and is subdivided into multiple temperature ranges which overlap in some instances. ITS-90 is the most recent of a series of International Temperature Scales adopted by the CIPM since 1927. Adopted at the 1989 General Conference on Weights and Measures, it supersedes the International Practical Temperature Scale of 1968 (amended edition of 1975) and the 1976 "Provisional 0.5 K to 30 K Temperature Scale". The CCT has also published several online guidebooks to aid realisations of the ITS-90. The lowest temperature covered by the ITS-90 is 0.6 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nicolas Léonard Sadi Carnot
''Sous-lieutenant'' Nicolas Léonard Sadi Carnot (; 1 June 1796 – 24 August 1832) was a French mechanical engineer in the French Army, military scientist and physicist, and often described as the "father of thermodynamics". He published only one book, the ''Reflections on the Motive Power of Fire'' (Paris, 1824), in which he expressed the first successful theory of the maximum efficiency of heat engines and laid the foundations of the new discipline: thermodynamics. Carnot's work attracted little attention during his lifetime, but it was later used by Rudolf Clausius and Lord Kelvin to formalize the second law of thermodynamics and define the concept of entropy. Based on purely technical concerns, such as improving the performance of the steam engine, Sadi Carnot's intellect laid the groundwork for modern science technological designs, such as the automobile or jet engine. His father Lazare Carnot was an eminent mathematician, military engineer, and leader of the French Revo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temperature
Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied on various reference points and thermometric substances for definition. The most common scales are the Celsius scale with the unit symbol °C (formerly called ''centigrade''), the Fahrenheit scale (°F), and the Kelvin scale (K), the latter being used predominantly for scientific purposes. The kelvin is one of the seven base units in the International System of Units (SI). Absolute zero, i.e., zero kelvin or −273.15 °C, is the lowest point in the thermodynamic temperature scale. Experimentally, it can be approached very closely but not actually reached, as recognized in the third law of thermodynamics. It would be impossible to extract energy as heat from a body at that temperature. Temperature is important in all fields of natur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physics
Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular succession of events." Physics is one of the most fundamental scientific disciplines, with its main goal being to understand how the universe behaves. "Physics is one of the most fundamental of the sciences. Scientists of all disciplines use the ideas of physics, including chemists who study the structure of molecules, paleontologists who try to reconstruct how dinosaurs walked, and climatologists who study how human activities affect the atmosphere and oceans. Physics is also the foundation of all engineering and technology. No engineer could design a flat-screen TV, an interplanetary spacecraft, or even a better mousetrap without first understanding the basic laws of physic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Numerical Analysis
Numerical analysis is the study of algorithms that use numerical approximation (as opposed to symbolic computation, symbolic manipulations) for the problems of mathematical analysis (as distinguished from discrete mathematics). It is the study of numerical methods that attempt at finding approximate solutions of problems rather than the exact ones. Numerical analysis finds application in all fields of engineering and the physical sciences, and in the 21st century also the life and social sciences, medicine, business and even the arts. Current growth in computing power has enabled the use of more complex numerical analysis, providing detailed and realistic mathematical models in science and engineering. Examples of numerical analysis include: ordinary differential equations as found in celestial mechanics (predicting the motions of planets, stars and galaxies), numerical linear algebra in data analysis, and stochastic differential equations and Markov chains for simulating living ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artifact (observational)
In natural science and signal processing, an artifact or artefact is any error in the perception or representation of any information introduced by the involved equipment or technique(s). Computer science In ''computer science'', digital artifacts are anomalies introduced into digital signals as a result of digital signal processing. Microscopy In '' microscopy'', visual artifacts are sometimes introduced during the processing of samples into slide form. Econometrics In ''econometrics'', which trades on computing relationships between related variables, an artifact is a spurious finding, such as one based on either a faulty choice of variables or an over-extension of the computed relationship. Such an artifact may be called a ''statistical artifact''. For instance, imagine a hypothetical finding that presidential approval rating is approximately equal to twice the percentage of citizens making more than $50,000 annually; if 60% of citizens make more than $50,000 annually, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simulation
A simulation is the imitation of the operation of a real-world process or system over time. Simulations require the use of Conceptual model, models; the model represents the key characteristics or behaviors of the selected system or process, whereas the simulation represents the evolution of the model over time. Often, computers are used to execute the computer simulation, simulation. Simulation is used in many contexts, such as simulation of technology for performance tuning or optimizing, safety engineering, testing, training, education, and video games. Simulation is also used with scientific modelling of natural systems or human systems to gain insight into their functioning, as in economics. Simulation can be used to show the eventual real effects of alternative conditions and courses of action. Simulation is also used when the real system cannot be engaged, because it may not be accessible, or it may be dangerous or unacceptable to engage, or it is being designed bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duck Test
The duck test is a form of abductive reasoning, usually expressed as "If it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck." The test implies that a person can identify an unknown subject by observing that subject's habitual characteristics. It is sometimes used to counter abstruse arguments that something is not what it appears to be. History The French automaton maker Jacques de Vaucanson created a mechanical duck in 1738. The mechanical duck would quack, move its head to eat grain which it would appear to digest, and after a short time would excrete a mixture that looked and smelled like duck droppings. The irony is that while the phrase is often cited as proof of abductive reasoning, it is not proof, as the mechanical duck is still not a living duck. In popular culture Douglas Adams parodied this test in his book ''Dirk Gently's Holistic Detective Agency'': Monty Python also referenced the test in the Witch Logic scene i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subject-matter Expert
A subject-matter expert (SME) is a person who has authority, accumulated great knowledge in a particular field or topic and this level of knowledge is demonstrated by the person's degree, licensure, and/or through years of professional experience with the subject, i.e. a Doctor of Philosophy, PhD in chemistry could be easily declared as an SME in chemistry, or a person with a Second Class Radio Telegraph License (or equivalent) issued by the national licensing body (Federal Communications Commission in the United States, Ofcom in the UK, and National Telecommunications Commission in the Philippines, and other List_of_telecommunications_regulatory_bodies, authorities around the world) could be considered an SME in Morse_code, radio telegraph. A person with a master's degree in electronic engineering could be considered a subject matter expert in electronics, or a person with many years of experience in machining could be considered a subject matter expert in machining. The term is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Knowledge-based Engineering
Knowledge-based engineering (KBE) is the application of knowledge-based systems technology to the domain of manufacturing design and production. The design process is inherently a knowledge-intensive activity, so a great deal of the emphasis for KBE is on the use of knowledge-based technology to support computer-aided design (CAD) however knowledge-based techniques (e.g. knowledge management) can be applied to the entire product lifecycle. The CAD domain has always been an early adopter of software-engineering techniques used in knowledge-based systems, such as object-orientation and rules. Knowledge-based engineering integrates these technologies with CAD and other traditional engineering software tools. Benefits of KBE include improved collaboration of the design team due to knowledge management, improved re-use of design artifacts, and automation of major parts of the product lifecycle. Overview KBE is essentially engineering on the basis of knowledge models. A knowledge mode ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
