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Varying Permeability Model
The Varying Permeability Model, Variable Permeability Model or VPM is an algorithm that is used to calculate the decompression needed for ambient pressure dive profiles using specified breathing gases. It was developed by D.E. Yount and others for use in professional and recreational diving. It was developed to model laboratory observations of bubble formation and growth in both inanimate and in vivo systems exposed to pressure. In 1986, this model was applied by researchers at the University of Hawaiʻi to calculate diving decompression tables. Several variations of the algorithm have been used in mobile and desktop dive planning software and om dive computers. Theoretical basis The VPM presumes that microscopic bubble nuclei always exist in water and tissues that contain water. Any nuclei larger than a specific "critical" size, which is related to the maximum dive depth (exposure pressure), will grow during decompression when the diver ascends. The VPM aims to minimize the to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algorithm
In mathematics and computer science, an algorithm () is a finite sequence of Rigour#Mathematics, mathematically rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algorithms are used as specifications for performing calculations and data processing. More advanced algorithms can use Conditional (computer programming), conditionals to divert the code execution through various routes (referred to as automated decision-making) and deduce valid inferences (referred to as automated reasoning). In contrast, a Heuristic (computer science), heuristic is an approach to solving problems without well-defined correct or optimal results.David A. Grossman, Ophir Frieder, ''Information Retrieval: Algorithms and Heuristics'', 2nd edition, 2004, For example, although social media recommender systems are commonly called "algorithms", they actually rely on heuristics as there is no truly "correct" recommendation. As an e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dive Computer
A dive computer, personal decompression computer or decompression meter is a device used by an underwater diver to measure the elapsed time and depth during a dive and use this data to calculate and display an ascent profile which, according to the programmed decompression algorithm, will give a low risk of decompression sickness. A secondary function is to record the dive profile, warn the diver when certain events occur, and provide useful information about the environment. Dive computers are a development from decompression tables, the diver's watch and depth gauge, with greater accuracy and the ability to monitor dive profile data in real time. Most dive computers use real-time ambient pressure input to a decompression algorithm to indicate the remaining time to the no-stop limit, and after that has passed, the minimum decompression required to surface with an acceptable risk of decompression sickness. Several algorithms have been used, and various personal conservatism fac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HeinrichsWeikamp
HeinrichsWeikamp, based in Germany, is a company that produces sports precision instruments for scuba diving including personal dive computers and oxygen partial pressure monitors for diving rebreathers. Their products: OSTC, OSTC Mk.2, OSTC 2N, OSTC3, OSTC4 and Frog are supported by Subsurface, free software for logging dives authored by Linus Torvalds. History HeinrichsWeikamp was founded by Matthias Heinrichs in 2004. Products All Heinrichs Weikamp products are manufactured in their Freiburg im Breisgau Freiburg im Breisgau or simply Freiburg is the List of cities in Baden-Württemberg by population, fourth-largest city of the German state of Baden-Württemberg after Stuttgart, Mannheim and Karlsruhe. Its built-up area has a population of abou ...-based facility. OSTC Series * OSTC diving computer The first dive computer created by HeinrichsWeikamp with a coloured display and an open source-based firmware. With Bluetooth data transfer and wireless Qi standard ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shearwater Research
Shearwater Research is a Canadian manufacturer of dive computers and rebreather electronics for technical diving. History In 2004, Shearwater Research was founded by Bruce Partridge who produced their products in a spare bedroom at his home. As of 2014, Shearwater was producing thousands of dive computers per year in a manufacturing facility with twenty employees. From the beginning the company sought to develop products that are simple to use and easy to read underwater. Shearwater Research began by building controller boards for the Innerspace Systems Corp (ISC) Megalodon rebreathers in 2004. There was a problem with the configuration and by the end of 2005, ISC was no longer offering the Shearwater electronics package. Since that time, the initial issues have been resolved and Shearwater electronics are again available for use on the ISC Megalodons. Shearwater decompression computers began with an implementation of the Bühlmann decompression algorithm with gradient factor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subsurface (software)
Linus Benedict Torvalds ( , ; born 28 December 1969) is a Finnish software engineer who is the creator and lead developer of the Linux kernel. He also created the distributed version control system Git. He was honored, along with Shinya Yamanaka, with the 2012 Millennium Technology Prize by the Technology Academy Finland "in recognition of his creation of a new open source operating system for computers leading to the widely used Linux kernel". He is also the recipient of the 2014 IEEE Computer Society Computer Pioneer Award and the 2018 IEEE Masaru Ibuka Consumer Electronics Award. Life and career Early years Torvalds was born in Helsinki, Finland, on 28 December 1969, the son of journalists Anna and Nils Torvalds, the grandson of statistician Leo Törnqvist and of poet Ole Torvalds, and the great-grandson of journalist and soldier Toivo Karanko. His parents were campus radicals at the University of Helsinki in the 1960s. His family belongs to the Swedish-speaki ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Society Of Mechanical Engineers
The American Society of Mechanical Engineers (ASME) is an American professional association that, in its own words, "promotes the art, science, and practice of multidisciplinary engineering and allied sciences around the globe" via "continuing education, training and professional development, codes and technical standard, standards, research, conferences and publications, government relations, and other forms of outreach." ASME is thus an engineering society, a standards organization, a research and development organization, an advocacy organization, a provider of training and education, and a nonprofit organization. Founded as an engineering society focused on mechanical engineering in North America, ASME is today multidisciplinary and global. ASME has over 85,000 members in more than 135 countries worldwide. ASME was founded in 1880 by Alexander Lyman Holley, Henry Rossiter Worthington, John Edison Sweet and Matthias N. Forney in response to numerous steam boiler pressure vessel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Sea Grant Program
The National Sea Grant College Program is a program of the National Oceanic and Atmospheric Administration (NOAA) within the U.S. Department of Commerce. It is a national network of 34 university-based Sea Grant programs involved in scientific research, education, training, and extension projects geared toward the conservation and practical use of the coasts, Great Lakes, and other marine areas. The program is administered by the National Oceanic and Atmospheric Administration (NOAA) with the national office located in Silver Spring, Maryland. There are Sea Grant programs located in every coastal and Great Lakes state as well as in Puerto Rico and Guam. The program was instituted in 1966 when Congress passed the National Sea Grant College Program Act. Sea Grant programs and colleges are not to be confused with land-grant colleges (a program instituted in 1862), space-grant colleges (instituted in 1988), or sun-grant colleges (instituted in 2003), although an institution may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Undersea And Hyperbaric Medical Society
The Undersea and Hyperbaric Medical Society (UHMS) is an organization based in the US which supports research on matters of hyperbaric medicine and physiology, and provides a certificate of added qualification for physicians with an unrestricted license to practice medicine and for limited licensed practitioners, at the completion of the Program for Advanced Training in Hyperbaric Medicine. They support an extensive library and are a primary source of information for diving and hyperbaric medicine physiology worldwide. History The Undersea Medical Society (UMS) grew from the close associations of a small group of scientists. These men realized after a series of ''International Symposia on Underwater Physiology'', initiated by the University of Pennsylvania and the Office of Naval Research that there was a need to stimulate in the field of undersea medicine. This group consisted of diving and aerospace Dr's Edward L. Beckman, Jack L. Kinsey, Christian J. Lambertsen, Walter F. Ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pressure
Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and even by industry. Further, both spellings are often used ''within'' a particular industry or country. Industries in British English-speaking countries typically use the "gauge" spelling. is the pressure relative to the ambient pressure. Various #Units, units are used to express pressure. Some of these derive from a unit of force divided by a unit of area; the International System of Units, SI unit of pressure, the Pascal (unit), pascal (Pa), for example, is one newton (unit), newton per square metre (N/m2); similarly, the Pound (force), pound-force per square inch (Pound per square inch, psi, symbol lbf/in2) is the traditional unit of pressure in the imperial units, imperial and United States customary units, US customary systems. Pressure ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dive Planning Software
Dive planning is the process of planning an underwater diving operation. The purpose of dive planning is to increase the probability that a dive will be completed safely and the goals achieved. Some form of planning is done for most underwater dives, but the complexity and detail considered may vary enormously. Professional diving operations are usually formally planned and the plan documented as a legal record that due diligence has been done for health and safety purposes. Recreational dive planning may be less formal, but for complex technical dives, can be as formal, detailed and extensive as most professional dive plans. A professional diving contractor will be constrained by the code of practice, standing orders or regulatory legislation covering a project or specific operations within a project, and is responsible for ensuring that the scope of work to be done is within the scope of the rules relevant to that work. A recreational (including technical) diver or dive group i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decompression Practice
To prevent or minimize decompression sickness, divers must properly plan and monitor decompression. Divers follow a decompression model to safely allow the release of excess inert gases dissolved in their body tissues, which accumulated as a result of breathing at ambient pressures greater than surface atmospheric pressure. Decompression models take into account variables such as depth and time of dive, breathing gasses, altitude, and equipment to develop appropriate procedures for safe ascent. Decompression may be continuous or staged, where the ascent is interrupted by stops at regular depth intervals, but the entire ascent is part of the decompression, and ascent rate can be critical to harmless elimination of inert gas. What is commonly known as no-decompression diving, or more accurately no-stop decompression, relies on limiting ascent rate for avoidance of excessive bubble formation. Staged decompression may include deep stops depending on the theoretical model used fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decompression Tables
There are several categories of decompression equipment used to help divers decompress, which is the process required to allow divers to return to the surface safely after spending time underwater at higher ambient pressures. Decompression obligation for a given dive profile must be calculated and monitored to ensure that the risk of decompression sickness is controlled. Some equipment is specifically for these functions, both during planning before the dive and during the dive. Other equipment is used to mark the underwater position of the diver, as a position reference in low visibility or currents, or to assist the diver's ascent and control the depth. Decompression may be shortened ("accelerated") by breathing an oxygen-rich "decompression gas" such as a nitrox blend or pure oxygen. The high partial pressure of oxygen in such decompression mixes produces the effect known as the oxygen window. This decompression gas is often carried by scuba divers in side-slung cylinde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
