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This matching may be assessed in the lung as a whole, or in individual or in sub-groups of gas-exchanging units in the lung. On the other side Ventilation-perfusion mismatch is the term used when the ventilation and the perfusion of a gas exchanging unit are not matched. The actual values in the lung vary depending on the position within the lung.
A ventilation/perfusion lung scan, also called a V/Q lung scan, or ventilation/perfusion scintigraphy, is a type of medical imaging using scintigraphy and medical isotopes to evaluate the circulation of air and blood within a patient's lungs, [1] [2] in order to determine the ventilation/perfusion ratio.
Furthermore, adequate achievement of ventilation and perfusion matching is essential as it ensures the continuous supply of oxygen and withdrawal of waste products from the body. Thus, strict regulation of ventilation and perfusion is needed for efficient gas exchange .
Different matching methods, such as velocity matching and position matching, are designed to improve the speed and accuracy of the alignment. Different factors will affect the accuracy of the transfer alignment, such as reference information delay, mounting error, sensor measurement error, lever-arm effect [ 2 ] and flexure of the carrier body.
Alpha-EM [5] ⊃ log-EM ⊃ basic competitive learning (vector quantization, VQ; or clustering). On the class of the vector quantization and competitive learning, he contributed to generate and identify the hierarchy of VQs. VQ ⇔ {batch mode VQ, and learning VQ} [8] ⊂ {harmonic competition} [7] ⊂ {multiple descent cost competition}. [8]
Vector quantization (VQ) is a classical quantization technique from signal processing that allows the modeling of probability density functions by the distribution of prototype vectors. Developed in the early 1980s by Robert M. Gray , it was originally used for data compression .
The VA-file approach is a special case of a compression based search, where each feature component is compressed uniformly and independently. The optimal compression technique in multidimensional spaces is Vector Quantization (VQ), implemented through clustering. The database is clustered and the most "promising" clusters are retrieved.
Matched filters find use in seismology to detect similar earthquake or other seismic signals, often using multicomponent and/or multichannel empirically determined templates. [15] Matched filtering applications in seismology include the generation of large event catalogues to study earthquake seismicity [ 16 ] and volcanic activity, [ 17 ] [ 18 ...