Subject:
All Disciplines Arts & Humanities Biology & Life Sciences Business & Economics Chemistry & Materials Science Computer Science & Mathematics Engineering Environmental & Earth Sciences Medicine & Pharmacology Physical Sciences Public Health & Healthcare Social Sciences
Sort:
Hottest Latest Alphabetical (A-Z) Alphabetical (Z-A)
Type:
All Topic Review Biography
Topic Review
Multi-Environment Real-Time
Multi-Environment Real-Time (MERT), later renamed UNIX Real-Time (UNIX-RT), is a hybrid time-sharing and real-time operating system developed in the 1970s at Bell Labs for use in embedded minicomputers (especially PDP-11s). A version named Duplex Multi Environment Real Time (DMERT) was the operating system for the AT&T 3B20D telephone switching minicomputer, designed for high availability; DMERT was later renamed Unix RTR (Real-Time Reliable). A generalization of Bell Labs' time-sharing operating system Unix, MERT featured a redesigned, modular kernel that was able to run Unix programs and privileged real-time computing processes. These processes' data structures were isolated from other processes with message passing being the preferred form of interprocess communication (IPC), although shared memory was also implemented. MERT also had a custom file system with special support for large, contiguous, statically sized files, as used in real-time database applications. The design of MERT was influenced by Dijkstra's THE, Hansen's Monitor, and IBM's CP-67. The MERT operating system was a four-layer design, in decreasing order of protection: The standard supervisor was MERT/UNIX, a Unix emulator with an extended system call interface and shell that enabled the use of MERT's custom IPC mechanisms, although an RSX-11 emulator also existed.
  • 325
  • 27 Oct 2022
Topic Review
Transport Layer Security Security
This article discusses the security of the Transport Layer Security (TLS) internet protocol.
  • 747
  • 27 Oct 2022
Topic Review
Several Complex Variables
The theory of functions of several complex variables is the branch of mathematics dealing with complex-valued functions f(z1, z2, ... zn) on the space Cn of n-tuples of complex numbers. As in complex analysis, which is the case n = 1 but of a distinct character, these are not just any functions: they are supposed to be holomorphic or complex analytic, so that locally speaking they are power series in the variables zi. Equivalently, as it turns out, they are locally uniform limits of polynomials; or local solutions to the n-dimensional Cauchy–Riemann equations.
  • 437
  • 27 Oct 2022
Topic Review
IBM TopView
TopView is the first object-oriented, multitasking, and windowing, personal computer operating environment for PC DOS developed by IBM, announced in August 1984 and shipped in March 1985. TopView provided a text-mode (although it also ran in graphics mode) operating environment that allowed users to run more than one application at the same time on a PC. IBM demonstrated an early version of the product to key customers before making it generally available, around the time they shipped their new PC AT computer.
  • 355
  • 27 Oct 2022
Topic Review
Cyclic Quadrilateral
In Euclidean geometry, a cyclic quadrilateral or inscribed quadrilateral is a quadrilateral whose vertices all lie on a single circle. This circle is called the circumcircle or circumscribed circle, and the vertices are said to be concyclic. The center of the circle and its radius are called the circumcenter and the circumradius respectively. Other names for these quadrilaterals are concyclic quadrilateral and chordal quadrilateral, the latter since the sides of the quadrilateral are chords of the circumcircle. Usually the quadrilateral is assumed to be convex, but there are also crossed cyclic quadrilaterals. The formulas and properties given below are valid in the convex case. The word cyclic is from the Ancient Greek κύκλος (kuklos) which means "circle" or "wheel". All triangles have a circumcircle, but not all quadrilaterals do. An example of a quadrilateral that cannot be cyclic is a non-square rhombus. The section characterizations below states what necessary and sufficient conditions a quadrilateral must satisfy to have a circumcircle.
  • 2.5K
  • 27 Oct 2022
Topic Review
Bayesian Inference in Motor Learning
Bayesian inference is a statistical tool that can be applied to motor learning, specifically to adaptation. Adaptation is a short-term learning process involving gradual improvement in performance in response to a change in sensory information. Bayesian inference is used to describe the way the nervous system combines this sensory information with prior knowledge to estimate the position or other characteristics of something in the environment. Bayesian inference can also be used to show how information from multiple senses (e.g. visual and proprioception) can be combined for the same purpose. In either case, Bayesian inference dictates that the estimate is most influenced by whichever information is most certain.
  • 411
  • 27 Oct 2022
Topic Review
History of Programming Languages
History of Programming Languages (HOPL) is an infrequent ACM SIGPLAN conference. Past conferences were held in 1978, 1993, and 2007. The fourth conference was originally intended to take place in June 2020, but has been postponed.
  • 510
  • 27 Oct 2022
Topic Review
Network Medicine
Network medicine is the application of network science towards identifying, preventing, and treating diseases. This field focuses on using network topology and network dynamics towards identifying diseases and developing medical drugs. Biological networks, such as protein-protein interactions and metabolic pathways, are utilized by network medicine. Disease networks, which map relationships between diseases and biological factors, also play an important role in the field. Epidemiology is extensively studied using network science as well; social networks and transportation networks are used to model the spreading of disease across populations. Network medicine is a medically focused area of systems biology.
  • 418
  • 27 Oct 2022
Topic Review
Systems Theory in Anthropology
Systems theory in anthropology is an interdisciplinary, non-representative, non-referential, and non-Cartesian approach that brings together natural and social sciences to understand society in its complexity. The basic idea of a system theory in social science is to solve the classical problem of duality; mind-body, subject-object, form-content, signifier-signified, and structure-agency. System theory suggests that instead of creating closed categories into binaries (subject-object); the system should stay open so as to allow free flow of process and interactions. In this way the binaries are dissolved. Complex systems in nature—for example, ecosystems—involve a dynamic interaction of many variables (e.g. animals, plants, insects and bacteria; predators and prey; climate, the seasons and the weather, etc.) These interactions can adapt to changing conditions but maintain a balance both between the various parts and as a whole; this balance is maintained through homeostasis. Human societies are complex systems, as it were, human ecosystems. Early humans, as hunter-gatherers, recognized and worked within the parameters of the complex systems in nature and their lives were circumscribed by the realities of nature. But they couldn't explain complex systems. Only in recent centuries did the need arise to define complex systems scientifically. Complex systems theories first developed in math in the late 19th century, then in biology in the 1920s to explain ecosystems, then to deal with artificial intelligence (cybernetics), etc. Anthropologist Gregory Bateson is the most influential and earliest founder of system theory in social sciences. In the 1940s, as a result of the Macy conferences, he immediately recognized its application to human societies with their many variables and the flexible but sustainable balance that they maintain. Bateson describes system as "any unit containing feedback structure and therefore competent to process information." Thus an open system allows interaction between concepts and materiality or subject and the environment or abstract and real. In natural science, systems theory has been a widely used approach. Austrian biologist, Karl Ludwig von Bertalanffy, developed the idea of the general systems theory (GST). The GST is a multidisciplinary approach of system analysis.
  • 647
  • 27 Oct 2022
Topic Review
Health Service Executive Cyberattack
On 14 May 2021, the Health Service Executive (HSE) of the Republic of Ireland suffered a major ransomware cyberattack that caused all of its IT systems nationwide to be shut down. It was the most significant cybercrime attack on an Irish state agency. Bloomberg News reported that the attackers used the Conti ransomware. The group responsible was identified as a criminal gang known as Wizard Spider, believed to be operating from Russia. The same group is believed to have attacked the Department of Health with a similar cyberattack. On 19 May, the Financial Times reviewed private data for twelve individuals which had appeared online as a result of the breach, with admission records and test results present in one case.
  • 212
  • 27 Oct 2022
  • Page
  • of
  • 371
Featured Entry Collections
>>

Featured Books

>>
Encyclopedia of Social Sciences
Encyclopedia of COVID-19
Encyclopedia of Fungi
Encyclopedia of Digital Society, Industry 5.0 and Smart City
Video Production Service
Feedback