Viviendo a Pesar de la Crisis: Algoritmo Bühlmann (Decompression Algorithm) del Dr. Albert Alois Bühlmann

Muy buenas,

A ver, ya que estamos (https://viviendoapesardelacrisis.blogspot.com/2023/05/shearwater-teric-swift-smart-ai.html):

https://en.wikipedia.org/wiki/Albert_A._B%C3%BChlmann

https://en.wikipedia.org/wiki/B%C3%BChlmann_decompression_algorithm

ZH-L 16 (1986):
-ZH-L 16 or ZH-L 16 A (air, nitrox): The experimental set of parameters published in 1986.
-ZH-L 16 B (air, nitrox): The set of parameters modified for printed dive table production, using slightly more conservative “a” values for tissue compartments #6, 7, 8 and 13.
-ZH-L 16 C (air, nitrox): The set of parameters with more conservative “a” values for tissue compartments #5 to 15. For use in dive computers.
-ZH-L 16 (helium): The set of parameters for use with helium.
-ZH-L 16 ADT MB: set of parameters and specific algorithm used by Uwatec for their trimix-enabled computers. Modified in the middle compartments from the original ZHL-C, is adaptive to diver workload and includes Profile-Determined Intermediate Stops. Profile modification is by means of "MB Levels", personal option conservatism settings, which are not defined in the manual.

Velocidad de ascenso:

Ascent rates:
Ascent rate is intrinsically a variable, and may be selected by the programmer or user for table generation or simulations, and measured as real-time input in dive computer applications.
The rate of ascent to the first stop is limited to 3 bar per minute for compartments 1 to 5, 2 bar per minute for compartments 6 and 7, and 1 bar per minute for compartments 8 to 16. Chamber decompression may be continuous, or if stops are preferred they may be done at intervals of 1 or 3 m.

Gradient Factors:

Gradient factors (GF):
Gradient factors are a calculation trick (Erik C. Baker) that consists of taking a percentage of each M-Value (e.g. 90%) in order to increase conservatism (shorter duration without mandatory stops, longer and/or deeper stops) by reducing the maximum amount of neutral (inert) gas (e.g. nitrogen) accepted when approaching the surface (Maximum Value of each tissue compartment at... 9 m, 6 m, 3 m, surface).
It is generally possible to define two GFs: GFlow and GFhigh. GFlow applies to the first (deepest) stop, GFhigh to the last stop (closest to the surface). Any intermediate GFs (between GFlow and GFhigh) are calculated by linear interpolation.
For dives without mandatory stops, only GFhigh is used, even if a GFlow is defined.
Twin GFs (e.g. 80/80) have the same effect as artificially increasing dive time (the time taken into account is greater than the actual time). When using printed dive tables, it is like an "impromptu addition of extra increments of depth and time beyond those actually required by the dive, universally known as Jesus-factoring".
Asymmetric GFs (e.g. 30/70) can be used to force deep stops. Deep stops can be defined as follows: “one or more voluntary or empirically derived decompression stops that are deeper than any prescribed by the algorithm utilized”.[21]
GFs can be implemented in dive computers in three ways:
-with a preset mode (e.g. L0, L1, L2 ... or P0, P1, P2 ...) corresponding to a decreasing pair of GFs: 90/90; 85/85; 80/80... ;
-leaving GFlow and GFhigh free for input;
-by including in the algorithm a modification of the GFs according to the diver's behaviour (profile, ascent speed, etc.).
In all cases, the choice of GF values is arbitrary.
The term "ZH-L 16 with GF" is misleading. It may give the impression that there is a specific set of parameters for use with GFs. There isn't. Any set of parameters with M-Values (ZH-L, US-Navy, Hahn, RGBM, Comex...) can be used with GF.

Shearwater:

https://www.shearwater.com/wp-content/uploads/2012/08/Shearwater-GF-V3.pdf

Garmin:

https://www.garmin.com/en-US/garmin-technology/dive-science/In-dive-features/buhlmann/

Suunto:

https://www.suunto.com/es-es/Asistencia/faq-articles/eon-core-and-steel/como-instalo-el-algoritmo-de-buceo-buhlmann-en-mi-eon-steel/

https://www.suunto.com/es-es/Asistencia/Asistencia-de-productos/suunto_eon_steel_black/suunto_eon_steel_black/caracteristicas/algoritmos-de-descompresion/

Validation of algorithms used in commercial off-the-shelf dive computer:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6355308/

Introduction:
Whilst the US Navy has been very systematic about validating Navy dive computer algorithms, there has been little documented or published evidence of rigorous testing of the algorithms in commercial off-the-shelf dive computers. This paper reports the evaluation of four algorithms used in these − Bühlmann ZHL-16C; VPM-B; Suunto-RGBM; EMC-20H − by comparison with US Navy experimental dives with known decompression sickness outcomes.

Methods:
Three specific tests were developed to test the algorithms' ability to mitigate decompression sickness: Total decompression time; no stop times and first stop depth. Output of commercial decompression algorithms were compared to either the probability of decompression sickness (PDCS) results from US Navy man-trials or statistical models derived from PDCS data. The algorithms were first tested with default conservative factors, then these factors were adjusted if the tests were not initially passed. The last verification step was to compare the output of the wrist computer with that of the full desktop algorithm.

Results:
This testing indicated that, whilst none of the four passed all of the proposed tests with factory-default conservatism, ZHL-16C and Suunto-RGBM could be made to pass by adjusting user-defined settings.

OVERALL ASSESSMENT:
The assessment results are summarised in Table 3. Based on an initial analysis, it can be inferred reasonably that none of the four algorithms evaluated passed all of the tests with default settings. ZHL-16C could be adjusted to pass all of the tests with GF-Hi < = 70 and GF-Lo > = 55. Suunto-RGBM could be made to pass all of the tests by simply turning off the deep stop option, which is easily done on the wrist unit tested. VPM-B could be adjusted to prescribe sufficient TDT (the required conservatism factor depends on the depth-bottom time of the dive) but could not be adjusted to pass the first significant stop test; the first stop was always too deep. EMC-20H could be tuned to pass the TDT test (conservatism ∼ 50%) and the first stop test (conservatism < 5%) independently, but not simultaneously.