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Reduced Gradient Bubble Model
The reduced gradient bubble model (RGBM) is an algorithm developed by Bruce Wienke for calculating decompression stops needed for a particular dive profile. It is related to the Varying Permeability Model. but is conceptually different in that it rejects the gel-bubble model of the varying permeability model. It is used in several dive computers, particularly those made by Suunto, Aqwary, Mares, HydroSpace Engineering, and Underwater Technologies Center. It is characterised by the following assumptions: blood flow (perfusion) provides a limit for tissue gas penetration by diffusion; an exponential distribution In probability theory and statistics, the exponential distribution or negative exponential distribution is the probability distribution of the distance between events in a Poisson point process, i.e., a process in which events occur continuousl ... of sizes of bubble seeds is always present, with many more small seeds than large ones; bubbles are permeable to gas trans ... [...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] |
Bruce Wienke
The reduced gradient bubble model (RGBM) is an algorithm developed by Bruce Wienke for calculating decompression stops needed for a particular dive profile. It is related to the Varying Permeability Model. but is conceptually different in that it rejects the gel-bubble model of the varying permeability model. It is used in several dive computers, particularly those made by Suunto, Aqwary, Mares, HydroSpace Engineering, and Underwater Technologies Center. It is characterised by the following assumptions: blood flow (perfusion) provides a limit for tissue gas penetration by diffusion; an exponential distribution In probability theory and statistics, the exponential distribution or negative exponential distribution is the probability distribution of the distance between events in a Poisson point process, i.e., a process in which events occur continuousl ... of sizes of bubble seeds is always present, with many more small seeds than large ones; bubbles are permeable to gas trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decompression Stop
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 f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dive Profile
A dive profile is a description of a diver's pressure exposure over time. It may be as simple as just a depth and time pair, as in: "sixty for twenty," (a bottom time of 20 minutes at a depth of 60 feet) or as complex as a second by second graphical representation of depth and time recorded by a personal dive computer. Several common types of dive profile are specifically named, and these may be characteristic of the purpose of the dive. For example, a Professional diving, working dive at a limited location will often follow a constant depth (square) profile, and a Recreational diving, recreational dive is likely to follow a multilevel profile, as the divers start deep and work their way up a reef to get the most out of the available breathing gas. The names are usually descriptive of the graphic appearance. The intended dive profile is useful as a Dive planning, planning tool as an indication of the risks of decompression sickness and oxygen toxicity for the exposure, to calcul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
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] |
Suunto
Suunto Oy is a Finland, Finnish company that manufactures and markets sports watches, dive computers, compasses and precision instruments. Headquartered in Vantaa, Finland, Suunto employs more than 300 people worldwide, and its products are sold in over 100 countries. Although globally active, the headquarters is placed next to the factory, in which most of the work stages are still handcrafted. Suunto was a subsidiary of Amer Sports, owned since 2019 by the Chinese group Anta Sports, with sister brands Wilson Sporting Goods, Wilson, Atomic Skis, Atomic, Sports Tracker, Salomon Group, Salomon, Precor, Arc'teryx. In May 2022, Chinese technology company Liesheng acquired Suunto from Amer Sports. The company's name comes from the Finnish word , meaning "direction" or "path", or in navigation, "bearing" or "heading". History In 1932 the company's founder, Tuomas Vohlonen, a surveyor by profession, applied for a patent for a unique method of filling and sealing a lightweight compa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mares (scuba Equipment)
Mares is a manufacturer of scuba equipment. Founded in 1949 by Ludovico Mares in Rapallo, Italy, the company initially made diving masks and spearguns. It has since expanded to become one of the largest scuba manufacturers, having merged with US manufacturer Dacor. Products The Mares product range includes the following products: * Diving regulators - Both first stage and second stage regulators * Dive computers * Instruments - compasses, pressure gauges, Personal computer interfaces for their dive computers and watches * B.C.D.s * Diving Wear – including wetsuits, drysuits and rash guards * Fins * Diving masks and snorkels * Accessories - Their accessories line includes dive torches, knives, surface marker buoys, diving sportswear, bags, weight belts, hangers, dry boxes, etc. In 2019, Mares entered the rebreather A rebreather is a breathing apparatus that absorbs the carbon dioxide of a user's exhaled breath to permit the rebreathing (recycling) of the substantia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfusion
Perfusion is the passage of fluid through the circulatory system or lymphatic system to an organ (anatomy), organ or a tissue (biology), tissue, usually referring to the delivery of blood to a capillary bed in tissue. Perfusion may also refer to fixation via perfusion, used in histological studies. Perfusion is measured as the rate at which blood is delivered to tissue, or volume of blood per unit time (blood volumetric flow rate, flow) per unit tissue mass. The SI unit is m3/(s·kg), although for human organs perfusion is typically reported in ml/min/g. The word is derived from the French verb ''perfuser'', meaning to "pour over or through". All animal tissues require an adequate blood supply for health and life. Poor perfusion (malperfusion), that is, ischemia, causes health problems, as seen in cardiovascular disease, including coronary artery disease, cerebrovascular disease, peripheral artery disease, and many other conditions. Tests verifying that adequate perfusion exists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffusion
Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical potential. It is possible to diffuse "uphill" from a region of lower concentration to a region of higher concentration, as in spinodal decomposition. Diffusion is a stochastic process due to the inherent randomness of the diffusing entity and can be used to model many real-life stochastic scenarios. Therefore, diffusion and the corresponding mathematical models are used in several fields beyond physics, such as statistics, probability theory, information theory, neural networks, finance, and marketing. The concept of diffusion is widely used in many fields, including physics (Molecular diffusion, particle diffusion), chemistry, biology, sociology, economics, statistics, data science, and finance (diffusion of people, ideas, data and price v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exponential Distribution
In probability theory and statistics, the exponential distribution or negative exponential distribution is the probability distribution of the distance between events in a Poisson point process, i.e., a process in which events occur continuously and independently at a constant average rate; the distance parameter could be any meaningful mono-dimensional measure of the process, such as time between production errors, or length along a roll of fabric in the weaving manufacturing process. It is a particular case of the gamma distribution. It is the continuous analogue of the geometric distribution, and it has the key property of being memoryless. In addition to being used for the analysis of Poisson point processes it is found in various other contexts. The exponential distribution is not the same as the class of exponential families of distributions. This is a large class of probability distributions that includes the exponential distribution as one of its members, but also includ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Scott Haldane
John Scott Haldane (; 2 May 1860 – 14/15 March 1936) was a Scottish physician physiologist and philosopher famous for intrepid self-experimentation which led to many important discoveries about the human body and the nature of gases. He also experimented on his son, the celebrated and polymathic biologist J. B. S. Haldane, even when he was quite young. Haldane locked himself in sealed chambers breathing potentially lethal cocktails of gases while recording their effect on his mind and body. Haldane visited the scenes of many mining disasters and investigated their causes. When the Germans used poison gas in World War I, Haldane went to the front at the request of Lord Kitchener and attempted to identify the gases being used. One outcome of this was his invention of a respirator, known as the black veil. Haldane's investigations into decompression sickness resulted in the concept of staged decompression, and the first reasonably reliable decompression tables, and his m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
