The Yale shooting problem is a conundrum or scenario in formal situational logic on which early logical solutions to the frame problem fail. The name of this problem comes from a scenario proposed by its inventors, Steve Hanks and Drew McDermott, working at Yale University when they proposed it. In this scenario, Fred (later identified as a turkey) is initially alive and a gun is initially unloaded. Loading the gun, waiting for a moment, and then shooting the gun at Fred is expected to kill Fred. However, if inertia is formalized in logic by minimizing the changes in this situation, then it cannot be uniquely proved that Fred is dead after loading, waiting, and shooting. In one solution, Fred indeed dies; in another (also logically correct) solution, the gun becomes mysteriously unloaded and Fred survives. Technically, this scenario is described by two fluents (a fluent is a condition that can change truth value over time): a l i v e {\displaystyle alive} and l o a d e d {\displaystyle loaded} . Initially, the first condition is true and the second is false. Then, the gun is loaded, some time passes, and the gun is fired. Such problems can be formalized in logic by considering four time points 0 {\displaystyle 0} , 1 {\displaystyle 1} , 2 {\displaystyle 2} , and 3 {\displaystyle 3} , and turning every fluent such as a l i v e {\displaystyle alive} into a predicate a l i v e ( t ) {\displaystyle alive(t)} depending on time. A direct formalization of the statement of the Yale shooting problem in logic is the following one: a l i v e ( 0 ) {\displaystyle alive(0)} ¬ l o a d e d ( 0 ) {\displaystyle \neg loaded(0)} t r u e → l o a d e d ( 1 ) {\displaystyle true\rightarrow loaded(1)} l o a d e d ( 2 ) → ¬ a l i v e ( 3 ) {\displaystyle loaded(2)\rightarrow \neg alive(3)} The first two formulae represent the initial state. The third formula formalizes the effect of loading the gun at time 1 {\displaystyle 1} . The fourth formula formalizes the effect of shooting at Fred at time 2 {\displaystyle 2} . This is a simplified formalization in which action names are neglected and the effects of actions are directly specified for the time points in which the actions are executed. See situation calculus for details. The formulae above, while being direct formalizations of the known facts, do not suffice to correctly characterize the domain. Indeed, ¬ a l i v e ( 1 ) {\displaystyle \neg alive(1)} is consistent with all these formulae, although there is no reason to believe that Fred dies before the gun has been shot. The problem is that the formulae above only include the effects of actions, but do not specify that all fluents not changed by the actions remain the same. In other words, a formula a l i v e ( 0 ) ≡ a l i v e ( 1 ) {\displaystyle alive(0)\equiv alive(1)} must be added to formalize the implicit assumption that loading the gun only changes the value of l o a d e d {\displaystyle loaded} and not the value of a l i v e {\displaystyle alive} . The necessity of a large number of formulae stating the obvious fact that conditions do not change unless an action changes them is known as the frame problem. An early solution to the frame problem was based on minimizing the changes. In other words, the scenario is formalized by the formulae above (that specify only the effects of actions) and by the assumption that the changes in the fluents over time are as minimal as possible. The rationale is that the formulae above enforce all effect of actions to take place, while minimization should restrict the changes to exactly those due to the actions. In the Yale shooting scenario, one possible evaluation of the fluents in which the changes are minimized is the following one. This is the expected solution. It contains two fluent changes: l o a d e d {\displaystyle loaded} becomes true at time 1 and a l i v e {\displaystyle alive} becomes false at time 3. The following evaluation also satisfies all formulae above. In this evaluation, there are still two changes only: l o a d e d {\displaystyle loaded} becomes true at time 1 and false at time 2. As a result, this evaluation is considered a valid description of the evolution of the state, although there is no valid reason to explain l o a d e d {\displaystyle loaded} being false at time 2. The fact that minimization of changes leads to wrong solution is the motivation for the introduction of the Yale shooting problem. While the Yale shooting problem has been considered a severe obstacle to the use of logic for formalizing dynamical scenarios, solutions to it have been known since the late 1980s. One solution involves the use of predicate completion in the specification of actions: in this solution, the fact that shooting causes Fred to die is formalized by the preconditions: alive and loaded, and the effect is that alive changes value (since alive was true before, this corresponds to alive becoming false). By turning this implication into an if and only if statement, the effects of shooting are correctly formalized. (Predicate completion is more complicated when there is more than one implication involved.) A solution proposed by Erik Sandewall was to include a new condition of occlusion, which formalizes the “permission to change” for a fluent. The effect of an action that might change a fluent is therefore that the fluent has the new value, and that the occlusion is made (temporarily) true. What is minimized is not the set of changes, but the set of occlusions being true. Another constraint specifying that no fluent changes unless occlusion is true completes this solution. The Yale shooting scenario is also correctly formalized by the Reiter version of the situation calculus, the fluent calculus, and the action description languages. In 2005, the 1985 paper in which the Yale shooting scenario was first described received the AAAI Classic Paper award. In spite of being a solved problem, that example is still sometimes mentioned in recent research papers, where it is used as an illustrative example (e.g., for explaining the syntax of a new logic for reasoning about actions), rather than being presented as a problem.
Auto-defrost
Auto-defrost, automatic defrost or self-defrosting is a technique which regularly defrosts the evaporator in a refrigerator or freezer. Appliances using this technique are often called frost free, frostless, or no-frost. == Mechanism == The defrost mechanism in a refrigerator heats the cooling element (evaporator coil) for a short period of time and melts the frost that has formed on it. The resulting water drains through a duct at the back of the unit. Defrosting is controlled by an electric or electronic timer. For every 6, 8, 10, 12 or 24 hours of compressor operation, it turns on a defrost heater for 15 minutes to half an hour. The defrost heater, having a typical power rating of 350W to 600W, is often mounted just below the evaporator in top and bottom-freezer models. It can also be located below and in the middle of the evaporator in side-by-side models. It may be protected from short circuits by means of fusible links. In older refrigerators, the timer runs continuously. In newer designs, the timer only runs while the compressor runs, so the longer the refrigerator door is closed, the less time the heater will run for and the more energy is saved. A defrost thermostat opens the heater circuit when the evaporator temperature rises above a preset temperature, 40°F (5°C) or more, thereby preventing excessive heating of the freezer compartment. The defrost timer is such that either the compressor or the defrost heater is on, but not both at the same time. Inside the freezer, air is circulated by means of one or more fans. In a typical design cold air from the freezer compartment is ducted to the fresh food compartment and circulated back into the freezer compartment. Air circulation helps sublimate any ice or frost that may form on frozen items in the freezer compartment. While defrosting, this fan is stopped to prevent heated-up air from reaching the food compartment. Instead of the normal cooling elements being embedded in the freezer liner, auto-defrost elements are behind or beneath the liner. This allows them to be heated for short periods of time to dispose of frost, without heating the contents of the freezer. Alternatively, some systems use the hot gas in the condenser to defrost the evaporator. This is done by means of a circuit that is cross-linked by a three-way valve. The hot gas quickly heats up the evaporator and defrosts it. This system is primarily used in commercial applications such as ice-cream displays. == Application == While this technique was originally applied to the refrigerator compartment, it was later used for freezer compartment as well. A combined refrigerator/freezer which applies self-defrosting to the refrigerator compartment only is usually called "partial frost free" or semi-automatic defrost (some brands call these "Auto Defrost" while Frigidaire referred to their semi-automatic models as "Cycla-Matic," Kelvinator often named these models as "Cyclic Defrost" ). These refrigerators usually have a pan underneath where water from the melted frost in the refrigerator section evaporates. Freezers with automatic defrosting and combined refrigerator/freezer units which also apply self defrosting to their freezer compartment are called "frost free". The latter usually feature an air connection between the two compartments with the air passage to the refrigerator compartment regulated by a damper. By this means, a controlled portion of the air coming from the freezer reaches the refrigerator. Some older models have no air circulation between their freezer and refrigerator sections. Instead, they use an independent cooling system (for example: an evaporator coil with a defrost heater and a circulating fan in the freezer and a cold-plate or open-coil evaporator in the refrigerator. "Frost-Free" refrigerator/freezer units usually use a heating element to defrost their evaporators, a pan to collect and evaporate water from the frost that melts from the cold plate and/or evaporator coil, a timer which turns off the compressor and turns on the defrost element usually from once to 4 times a day for periods usually ranging from 15 to 30 minutes, a defrost limiter thermostat that turns off the heating element before the temperature rises too much while the timer is still in its defrost phase. Some models also feature a drain heater to prevent ice from blocking the drain. Other early types of refrigerators also use hot gas defrost instead of electric heaters. These reverse the evaporator and condenser sides for the defrost cycle. Some newer refrigerator/freezer models have a computer that monitors how many times each door is opened and uses this data to control defrost scheduling thereby reducing power use. == Advantages == No need to manually defrost the frost buildup, therefore power consumption will not increase with time. Food packaging is easier to see. Most frozen food will not stick together. Smells are limited, especially in total frost-free appliances because the air always circulates. Better temperature management. == Disadvantages == The system can be more expensive to run when usage is high and if the fan continues or starts to run when the door is opened. A thermal cutout safety device is required to prevent overheating of the heating element. Increased electrical and mechanical complexity compared to a basic upright freezer or chest freezer, making it more prone to component failure. The temperature of the freezer contents rises during the defrosting cycles, especially if there is a light load in the freezer. This can cause "freezer burn" on articles placed in the freezer, from partially defrosting, then re-freezing On hot, humid days condensation will sometimes form around the refrigerator doors. Defrosting may not be completed by the time the defrost timer cycles back to normal operation (especially in hot, humid conditions with frequent door openings), leaving ice/frost on the evaporator coils. This condition can lead to "icing" which will interfere with the operation of the refrigerator. In laboratories, self-defrosting freezers must not be used to store certain delicate reagents such as enzymes, because the temperature cycling can degrade them. In addition, water can evaporate out of containers that do not have a very tight seal, altering the concentration of the reagents. Self-defrosting freezers should never be used to store flammable chemicals.
FoundationDB
FoundationDB is a free and open-source multi-model distributed NoSQL database owned by Apple Inc. with a shared-nothing architecture. The product was designed around a "core" database, with additional features supplied in "layers." The core database exposes an ordered key–value store with transactions. The transactions are able to read or write multiple keys stored on any machine in the cluster while fully supporting ACID properties. Transactions are used to implement a variety of data models via layers. The FoundationDB Alpha program began in January 2012 and concluded on March 4, 2013, with their public Beta release. Their 1.0 version was released for general availability on August 20, 2013. On March 24, 2015, it was reported that Apple has acquired the company. A notice on the FoundationDB web site indicated that the company has "evolved" its mission and would no longer offer downloads of the software. On April 19, 2018, Apple open sourced the software, releasing it under the Apache 2.0 license. == Main features == The main features of FoundationDB include the following: Ordered key–value store In addition to supporting standard key-based reads and writes, the ordering property enables range reads that can efficiently scan large swaths of data. Transactions Transaction processing employs multiversion concurrency control for reads and optimistic concurrency for writes. Transactions can span multiple keys stored on multiple machines. ACID properties FoundationDB guarantees serializable isolation and strong durability via redundant storage on disk before transactions are considered committed. Layers Layers map new data models, APIs, and query languages to the FoundationDB core. They employ FoundationDB's ability to update multiple data elements in a single transaction, ensuring consistency. An example is their SQL layer. Commodity clusters FoundationDB is designed for deployment on distributed clusters of commodity hardware running Linux. Replication FoundationDB stores each piece of data on multiple machines according to a configurable replication factor. Triple replication is the recommended mode for clusters of 5 or more machines. Scalability FoundationDB is designed to support horizontal scaling through the addition of machines to a cluster while automatically handling data replication and partitioning. Systems supported FoundationDB supports packages for Linux, Windows, and macOS. The Linux version supports production clusters, while the Windows and macOS versions support local operation for development purposes. Configurations on Amazon EC2 are also supported. Programming language bindings FoundationDB supports language bindings for Python, Go, Ruby, Node.js, Java, PHP, and C, all of which are made available with the product. == Design limitations == The design of FoundationDB results in several limitations: Long transactions FoundationDB does not support transactions running over five seconds. Large transactions Transaction size cannot exceed 10 MB of total written keys and values. Large keys and values Keys cannot exceed 10 kB in size. Values cannot exceed 100 kB in size. == History == FoundationDB, headquartered in Vienna, Virginia, was started in 2009 by Nick Lavezzo, Dave Rosenthal, and Dave Scherer, drawing on their experience in executive and technology roles at their previous company, Visual Sciences. In March 2015 the FoundationDB Community site was updated to state that the company had changed directions and would no longer be offering downloads of its product. The company was acquired by Apple Inc., which was confirmed March 25, 2015. On April 19, 2018, Apple open sourced the software, releasing it under the Apache 2.0 license.
Cybernetic Serendipity
Cybernetic Serendipity was an exhibition of cybernetic art curated by Jasia Reichardt, shown at the Institute of Contemporary Arts, London, England, from 2 August to 20 October 1968, and then toured across the United States. Two stops in the United States were the Corcoran Annex (Corcoran Gallery of Art), Washington, D.C., from 16 July to 31 August 1969, and the newly opened Exploratorium in San Francisco, from 1 November to 18 December 1969. == Content == One part of the exhibition was concerned with algorithms and devices for generating music. Some exhibits were pamphlets describing the algorithms, whilst others showed musical notation produced by computers. Devices made musical effects and played tapes of sounds made by computers. Peter Zinovieff lent part of his studio equipment - visitors could sing or whistle a tune into a microphone and his equipment would improvise a piece of music based on the tune. Another part described computer projects such as Gustav Metzger's self-destructive Five Screens With Computer, a design for a new hospital, a computer programmed structure, and dance choreography. The machines and installations were a very noticeable part of the exhibition. Gordon Pask produced a collection of large mobiles (Colloquy of Mobiles (1968)) with interacting parts that let the viewers join in the conversation. Many machines formed kinetic environments or displayed moving images. Bruce Lacey contributed his radio-controlled robots and a light-sensitive owl. Nam June Paik was represented by Robot K-456 and televisions with distorted images. Jean Tinguely provided two of his painting machines. Edward Ihnatowicz's biomorphic hydraulic ear (Sound Activated Mobile (SAM, 1968)) turned toward sounds and John Billingsley's Albert 1967 turned to face light. Wen-Ying Tsai presented his interactive cybernetic sculptures of vibrating stainless-steel rods, stroboscopic light, and audio feedback control. Several artists exhibited machines that drew patterns that the visitor could take away, or involved visitors in games. Cartoonist Rowland Emett designed the mechanical computer Forget-me-not, which was commissioned by Honeywell. Another section explored the computer's ability to produce text - both essays and poetry. Different programs produced Haiku, children's stories, and essays. One of the first computer-generated poems, by Alison Knowles and James Tenney, was included in the exhibition and catalogue. Computer-generated movies were represented by John Whitney's Permutations and a Bell Labs movie on their technology for producing movies. Some samples included images of tesseracts rotating in four dimensions, a satellite orbiting the Earth, and an animated data structure. Computer graphics were also represented, including pictures produced on cathode ray oscilloscopes and digital plotters. There was a variety of posters and graphics demonstrating the power of computers to do complex (and apparently random) calculations. Other graphics showed a simulated Mondrian and the iconic decreasing squares spiral that appeared on the exhibition's poster and book. The Boeing Company exhibited their use of wireframe graphics. The innovative computer-generated sculpture, Quad 1, was displayed at the Cybernetic Serendipity exhibit. Created by the American abstract expressionist sculptor, Robert Mallary, in 1968, Quad 1 is widely believed to be the world's first Computer Aided Design sculpture. Keith Albarn & Partners contributed to the design of the exhibition. Reflecting the prominence of music in the show, a ten-track album Cybernetic Serendipity Music was released by the ICA to accompany the show. Artists featured included Iannis Xenakis, John Cage, and Peter Zinovieff, a detail of whose graphic score for 'Four Sacred April Rounds’ (1968) was used as the cover artwork. == Attendance == Time magazine noted that there had been 40,000 visitors to the London exhibition. Other reports suggested visitor numbers were as high as 44,000 to 60,000. However, the ICA did not accurately count visitors. == After-effects == The exhibition provided the energy for the formation of British Computer Arts Society which continued to explore the interaction between science, technology and art, and put on exhibitions (for example Event One at the Royal College of Art). Several pieces were purchased by the Exploratorium in 1971, some of which are on display to this day. In 2014 the ICA held a retrospective exhibition Cybernetic Serendipity: A Documentation which included documents, installation photographs, press reviews and publications and a series of discussions in one of which Peter Zinovieff took part. To coincide with the exhibition, Cybernetic Serendipity Music was re-released as a limited-edition vinyl LP by The Vinyl Factory. The Victoria and Albert Museum marked the 50th anniversary with an exhibition in 2018 entitled "Chance and Control: Art in the Age of Computers". The V&A exhibition included many works by artists who featured in the original ICA show, plus related ephemera. "Chance and Control" subsequently toured to Chester Visual Arts and Firstsite, Colchester. In 2020, The Centre Pompidou exhibited the replica of Gordon Pask's 1968 Colloquy of Mobiles, reproduced by Paul Pangaro and TJ McLeish in 2018. In 2022 the Australian National University's School of Cybernetics launched the school by presenting an exhibition Australian Cybernetic: a point through time. The exhibition included works from Cybernetic Serendipity (1968), Australia ‘75: Festival of Creative Arts and Science (1975), and contemporary pieces curated by the School of Cybernetics. In describing Reichardt's Cybernetic Serendipity exhibition the school stated that it "represented points of expanding the cybernetic imagination" and was a "ground-breaking" "glimpse of a future in which computers were entangled with people and cultures, and through this she fashioned a blueprint for the future of computing that has since inspired generations".
MinID
MinID is an electronic login system used to secure a range of internet services in the Norwegian public sector. The communication done with MinID is encrypted to secure information from unauthorized usage. Everyone registered in the Norwegian Population Register over the age of 13 years can create a public ID with MinID. As of April 2010, more than 2 million people living in Norway had created user accounts with MinID. To create a public ID, PIN-codes from the Norwegian Tax Administration are needed. == Purpose == The purpose of MinID is to communicate an electronic identity, so that users are authorized to use electronic services, in a secure way. MinID has a user database where social security numbers and PIN-codes are saved. MinID can be used to access more than 50 online services from various Norwegian public agencies, including the Norwegian Labour and Welfare Administration, the Directorate of Taxes and the State Educational Loan. == Controller == The Norwegian Digitalisation Agency (Digdir) is the controller of the personal data handled by MinID. The Norwegian Digitalisation Agency (Norwegian: Digitaliseringsdirektoratet) or Digdir is a government agency subordinate to the Ministry of Digitalisation and Public Governance. It is responsible for help the public sector achieve quality, efficiency, user friendliness, openness and participation, as well as helping the public sector be organized and led in a good way with good intersectoral cooperation. == User profile == Users of MinID have a user profile that contains their mobile phone number and/or e-mail address. This data is used to administrate MinID use. The e-mail address is needed in order to send the user a temporary password if he or she forgets the password. The phone number is needed in order to send an SMS-code at log in or a temporary password if the user forgets the password. == Transparency, correction and deletion == According to the law users can claim full access of the handling of their own personal data. Users also have the right to information about how this data are handled and saved, and how they can correct or delete inaccurate data. Users can at any time choose to delete themselves as a user of MinID. The user profile will then be deleted from the MinID user database. == Extradition to others == MinID passes on the user's social security number and chosen language to the public services he or she logs on to, so that the user can go to other public services without a new login.
Caspio
Caspio, Inc. is an American software company providing a low-code platform for building cloud-based business applications. Founded in 2000 by Frank Zamani, the company is headquartered in Sunnyvale, California, with operations in Poland, the Philippines, and Spain. Caspio’s platform allows organizations to create online database applications and workflow tools without extensive coding. == History == Caspio was founded by Frank Zamani in 2000. The company initially focused on simplifying custom cloud applications and reducing development time and cost as compared to traditional software development. Caspio released the first version of its platform, Caspio Bridge, in 2001. In 2014, Caspio released a HIPAA-Compliant Edition of its low-code application development platform. Caspio also released an EU General Data Protection Regulation (GDPR) Compliance Edition of its low-code application development platform in 2016. Caspio's second European Software Development Center opened in Kraków, Poland in 2017. In 2019, Forrester Research listed Caspio and three other platforms in its highest of four ranked tiers of twelve low-code platforms for business developers based on rankings of offerings and strategy at that time. Caspio also opened data centers in Montreal, Canada and India in 2020.
Vx-underground
vx-underground, also known as VXUG, is an educational website about malware and cybersecurity. It claims to have the largest online repository of malware. The site was launched in May, 2019 and has grown to host over 35 million pieces of malware samples. On their account on Twitter, VXUG reports on and verifies cybersecurity breaches. == Reception == Kim Crawley compared the site to VirusTotal and states that vx-underground is more susceptible to suspicion for law enforcement. == Data breach reports == In May 2024, the International Baccalaureate organizations faced allegations over supposed breaches in their IT infrastructure after an incident of examination leaks. Upon inspecting leaked data, VXUG were the first to report that the breach seemed legitimate on the morning of May 6.