Summary

HandWiki is the world's largest wiki-style encyclopedia dedicated to science, technology and computing. It allows you to create and edit articles as long as you have external citations and login account. In addition, this is a content management environment that can be used for collaborative editing of original scholarly content, such as books, manuals, monographs and tutorials.

Expand All
Entries
Topic Review
Belt Machine
In computer engineering and in programming language implementations, a belt machine is a real or emulated computer that uses a first in, first out (FIFO) queue rather than individual machine processor registers to evaluate each sub-expression in the program. A belt computer is programmed with an instruction set that specifies arguments explicitly but results implicitly. The common alternative to belt machines are register machines, in which each instruction explicitly names the specific registers to use for locations of operand arguments and results. Belt machines are related to stack machines, which specify both arguments and results implicitly using a pushdown stack. Other alternatives are accumulator machines, which have only one visible general-purpose temp register, and memory-to-memory machines, which have no visible temp registers. A belt machine implements temporary storage with a fixed-length FIFO queue, or belt by analogy to a conveyor belt. The operands of the arithmetic logic units (ALUs) and other functional units may be taken from any position on the belt, and the result from the computation is dropped (stored) in the front position of the belt, advancing the belt to make room. As the belt is fixed length, drops in the front are matched by older operands falling off the back; pushed-off operands become inaccessible and must be explicitly saved if still needed for later work. Most operations of the instruction set work only with data on the belt, not on data registers or main memory cells. For a typical instruction like add, both argument operands come from explicitly named positions on the belt, and the result is dropped on the front, ready for the next instruction. Operations with multiple results simply drop more values at the belt front. Most belt instructions are encoded as just an operation code (opcode) and two belt positions, with no added fields to specify a result register, memory address, or literal constant. This encoding is easily extended to richer operations with more than two inputs or more than one result. Constant operands are dropped by separate load immediate instructions. All access of program variables in main random-access memory (RAM) is segregated into separate load or store instructions containing one memory address, or some way to calculate that address from belt operands. All belt machines have variants of the load/store opcodes to access local variables and the heap. This can be by offsets, from a pointer on the belt, or from various special-purpose base registers. Similarly, there will be instructions to branch to an address taken from the belt, along with branches relative to the program counter.
  • 1.0K
  • 20 Oct 2022
Topic Review
Ethereum
Ethereum is a decentralized, open-source blockchain with smart contract functionality. Ether (ETH or Ξ) is the native cryptocurrency of the platform. Among cryptocurrencies, Ether is second only to Bitcoin in market capitalization. Ethereum was conceived in 2013 by programmer Vitalik Buterin. Additional founders of Ethereum included Gavin Wood, Charles Hoskinson, Anthony Di Iorio and Joseph Lubin. In 2014, development work began and was crowdfunded, and the network went live on 30 July 2015. Ethereum allows anyone to deploy permanent and immutable decentralized applications onto it, with which users can interact. Decentralized finance (DeFi) applications provide a broad array of financial services without the need for typical financial intermediaries like brokerages, exchanges, or banks, such as allowing cryptocurrency users to borrow against their holdings or lend them out for interest. Ethereum also allows users to create and exchange NFTs, which are unique tokens representing ownership of an associated asset or privilege, as recognized by any number of institutions. Additionally, many other cryptocurrencies utilize the ERC-20 token standard on top of the Ethereum blockchain and have utilized the platform for initial coin offerings. A series of upgrades called Ethereum 2.0 includes a transition to proof of stake and aims to increase transaction throughput by using sharding.
  • 22.7K
  • 20 Oct 2022
Topic Review
Elie Bursztein
Elie Bursztein (born 1 June 1980) leads the anti-abuse research team at Google.[r 1] He is best known for his research on anti-fraud and abuse,[r 2] his novel attacks against web service and video games and his work on applied cryptography.[p 1][p 2] Prior to Google Bursztein was a post-doctoral fellow in computer science at Stanford University, where he focused on CAPTCHAs security[p 3][p 4] and usability.[p 5][p 6]
  • 1.4K
  • 20 Oct 2022
Topic Review
Varidnaviria
Varidnaviria is a realm of viruses that includes all DNA viruses that encode major capsid proteins that contain a vertical jelly roll fold. The major capsid proteins (MCP) form into pseudohexameric subunits of the viral capsid, which stores the viral deoxyribonucleic acid (DNA), and are perpendicular, or vertical, to the surface of the capsid. Apart from this, viruses in the realm also share many other characteristics, such as minor capsid proteins (mCP) with the vertical jelly roll fold, an ATPase that packages viral DNA into the capsid, and a DNA polymerase that replicates the viral genome. Varidnaviria was established in 2019 based on the shared characteristics of the viruses in the realm. There are two groups of viruses in Varidnaviria: viruses that have a double vertical jelly roll (DJR) folds in the MCP, assigned to the kingdom Bamfordvirae, and viruses that have a single vertical jelly roll (SJR) fold in the MCP, assigned to the kingdom Helvetiavirae. The DJR-MCP lineage is thought to be descended from the SJR-MCP lineage via a gene fusion event, and the SJR-MCP shows a close relation to nucleoplasmins, pointing to a possible origin of the realm's jelly roll fold MCP. Most identified eukaryotic DNA viruses belong to Varidnaviria. Marine viruses in the realm are highly abundant worldwide and are important in marine ecology. Many animal viruses in the realm are associated with disease, including adenoviruses, poxviruses, and the African swine fever virus. Poxviruses have been prominent in the history of medicine, especially smallpox, caused by Variola virus, which was the target of the first vaccine and which later became the first disease eradicated. The realm also notably includes giant viruses that are physically larger and contain a much larger number of genes than typical viruses.
  • 1.6K
  • 20 Oct 2022
Topic Review
One Instruction Set Computer
A one instruction set computer (OISC), sometimes called an ultimate reduced instruction set computer (URISC), is an abstract machine that uses only one instruction – obviating the need for a machine language opcode. With a judicious choice for the single instruction and given infinite resources, an OISC is capable of being a universal computer in the same manner as traditional computers that have multiple instructions.:55 OISCs have been recommended as aids in teaching computer architecture:327:2 and have been used as computational models in structural computing research.
  • 885
  • 20 Oct 2022
Topic Review
Extremophiles in Biotechnology
Extremophiles in biotechnology is the application of organisms that thrive in extreme environments to biotechnology. Extremophiles are organisms that thrive in the most volatile environments on the planet and it is due to their talents that they haven begun playing a large role in biotechnology. These organisms live everywhere from environments of high acidity or salinity to areas with limited or no oxygen are places they call home. Scientists show keen interest in organisms with rare or strange talents and in the past 20-30 years extremophiles have been at the forefront with thousands of researchers delving into their abilities. The area in which there has been the most talk, research, and development in relation to these organisms is biotechnology. Scientists around the globe are either extracting DNA to modify genomes or directly using extremophiles to complete tasks. Thanks to the discovery and interest in these organisms the enzymes used in PCR were found, making the rapid replication of DNA in the lab possible. Since they gained the spotlight researchers have been amassing databases of genome data for the hopes that new traits and abilities can be used to further biotechnical advancements Everything from the biodegradation of waste to the production of new fuels is on the horizon with the developments made in the field of biotechnology. There are many different kinds of extremophiles with each kind favoring a different environment. These organisms have become more and more important to biotechnology as their genomes have been uncovered, revealing a plethora of genetic potential. Currently the main uses of extremophiles lies in processes such as PCR, biofuel generation and biomining, but there are many other smaller scale operations at play. There are also labs that have identified what they wish to do with extremophiles, but haven't been able to fully achieve their goals. While these large scale goals have not yet been met the scientific community is working towards their completion in hope of creating new technologies and processes.
  • 1.1K
  • 20 Oct 2022
Topic Review
Ringed Seals and Climate Change
Ringed seals are the smallest and most abundant member of the seal family that live in the Arctic and Sub-Arctic regions. The average life span of a ringed seal is 40 years, with a diet based mainly on Arctic cod and planktonic crustaceans. Typically about 5 feet (1.5 m) long, the ringed seal is known to be solitary with their main predator being polar bears. Recently, however, the biggest predator to ringed seals has been the changing temperature in the Arctic and the detrimental changes to sea ice that follow. With declines in snowpack and sea ice due to warming ocean and atmospheric temperatures, survival has become tougher for ringed seals in the Arctic and Sub-Arctic regions. Yet ringed seals are also potentially projected to thrive due to warming, considering the early extinction of their predators. Climate change is sure to change the fate of all ringed seals in the coming years for better or worse.
  • 1.6K
  • 20 Oct 2022
Topic Review
Ideas of Reference and Delusions of Reference
Ideas of reference and delusions of reference describe the phenomenon of an individual experiencing innocuous events or mere coincidences and believing they have strong personal significance. It is "the notion that everything one perceives in the world relates to one's own destiny", usually in a negative and hostile manner. In psychiatry, delusions of reference form part of the diagnostic criteria for psychotic illnesses such as schizophrenia, delusional disorder, bipolar disorder (during the elevated stages of mania), as well as schizotypal personality disorder. To a lesser extent, it can be a hallmark of paranoid personality disorder, as well as body dysmorphic disorder. Such symptoms can also be caused by intoxication, such as stimulants like methamphetamine.
  • 7.4K
  • 20 Oct 2022
Topic Review
Functional Attitude Theory
Functional attitude theory (FAT) suggests that beliefs and attitudes are influential to various psychological functions. Attitudes can be influential on many processes such as being utilitarian (useful), social, relating to values, or a reduction of cognitive dissonance. They can be beneficial and help people interact with the world. In the late 1950s when psychoanalysis and behaviorism reigned supreme as the foci of psychological studies, Smith, Bruner, and White (1956) and Katz (1960) separately and independently developed typologies of human attitudes in relation to the functions to which they believed the attitudes served. This theory proposes that attitudes are held by individuals because they are important and integral to psychological functioning. The function of an attitude is more important than whether the attitude is accurate or correct.
  • 2.5K
  • 20 Oct 2022
Topic Review
NASA Robots
NASA (National Aeronautics and Space Administration) robots are robotic devices used to aid, augment, or substitute for astronauts in order to do difficult or rote tasks such as repairs in dangerous environments (such as those with radiation or micrometeorite risks), routine procedures (video capture), etc.
  • 1.4K
  • 20 Oct 2022
  • Page
  • of
  • 863

Other Entry Collections

>>