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1

Comparing measurement correction of echo sounder in shallow-water area

Zheng Zhaoyong, Jiang Siyi, Zeng Weizhu

Acta Geophysica

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2022

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Vol. 70, no 4

1677--1686

EN

Error correction of echo sounder is very important for the accurate measurement of water-depth in shallow-water area. There are some issues in measuring the water depth, they are accuracy, resolution, inaccurate beamwidth of transmit and can be solved by the existing methodologies. In this article, comparing measurement is an efficient method for error correction of echo sounder. The most commonly used comparing methods are sounding poles, plumb-lines and thermohaline methods. However, the sounding poles method can only measure the water-depth less than 5 m as its limited by the length of measuring poles; the plumb-lines method cannot guarantee the accuracy of water-depth value as its difficult to determine whether the plumb-line falls vertically onto the water floor or into the underwater sediment; the thermohaline methods is time-consuming as its need lots of the temperature and salinity information for the correction of sound velocity. Based on these knowledge and experience, we put forward a comparator for comparing measurement of water-depth, which could adjust sound velocity of echo sounder for precisely measure actual water-depth of the survey area without complicated thermohaline correction work. The comparator method has practical implications for the quick error correction of echo sounder survey in shallow water area. The experimental results predict that the mistakes are easily caused by the complicated correction work which can be avoided and establishes that the water-depth measurement is more efficient.

2

Koncepcja zastosowania metody porównywania parami wykorzystującej ważoną relację przewyższania do porównania zarysów okrągłości

Adamczak S., Kmiecik-Sołtysiak U.

Mechanik

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2014

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R. 87, nr 8-9CD1

156-161

PL

Dotychczas w praktyce porównywanie zarysów okrągłości otrzymanych w wyniku pomiaru metodą odniesieniową z zarysem otrzymanym metodą bezodniesieniową (wzorcową) opierało się na wizualnej ocenie. Istnieją również koncepcje statystycznego porównywania przyrządów pomiarowych. Przedstawiono istotę metody porównywania parami wykorzystującej ważoną relację przewyższania do szacowania podobieństwa zarysów okrągłości. Do zastosowania metody konieczne jest dokonanie analizy harmonicznej, która umożliwia wyznaczenie zadanych parametrów rozwinięcia w trygonometryczny szereg Fouriera porównywanych zarysów.

EN

Profiles of the geometrical surface structure were compared mainly visually. Profiles of roundness are measured by V-block roundness measurement and radius change method (reference device). There are statistical methods for comparison of measuring instruments accuracy. The authors suggest application of method of paired comparisons with weighted mean to assimilate profiles of roundness. For the obtained profiles a harmonic analysis is performed applying the Fast Fourier Transform to determine the pre-defined parameters.

3

Measurement of tissue pressure with symptoms of compartment syndrome

Živéak J., Šimšik D.

Acta of Bioengineering and Biomechanics

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2002

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Vol. 4, nr 2

101-104

EN

The increase in the tissue pressure (TP) in the compartment can be due to the internal pressure (contusion, swelling, inflammation), or due to the external pressure (tight bandage, pneumatic splint). Injury and a deep thrombosis of a blood vessel lead to the stasis and subsequently to the lowering of arterial-venous gradient just the same as this associated with lowering of arterial medium pressure due to the shock with the excessive positioning of the extremity. Our aim was to establish the value of TP and thus to prevent the symptoms of the compartment syndrome. Tte above-mentioned problem can be solved by measuring the tissue pressure in a real time, where the approximation of an invasive and a non-invasive pressure is proved by a comparative measurement.