scholarly journals Development of an Estimation Instrument of Acoustic Lens Properties for Medical Ultrasound Transducers

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Hojong Choi ◽  
Jongseon Johnson Jeong ◽  
Jungsuk Kim
Keyword(s):  
Attenuation Coefficient ◽  
Cost Estimation ◽  
Measurement Errors ◽  
Low Cost ◽  
Accurate Information ◽  
Ultrasound Transducers ◽  
Medical Ultrasound ◽  
Acoustic Lens ◽  
Pass Through ◽  
Lens Material

In medical ultrasound transducers, the transmission mode (pass-through) approach has been used to estimate the characteristics of the acoustic lens. However, it is difficult to measure the acoustic lens properties with high precision because of human, systemic, or mechanical measurement errors. In this paper, we propose a low-cost estimation instrument for acoustic lens properties connected with a customized database. In the instrument, three-axis and one-axis transmitting and material fixtures accurately align the transmitting and receiving transducers separately. Through the developed instrument, we obtained a precise standard deviation of the attenuation coefficient and velocity of the acoustic lens material of 0.05 dB/cm and 2.62 m/s, respectively. Additionally, the simultaneous alignment between the fixtures is controllable with developed programs, thus generating very accurate information of the acoustic lens about the testing ultrasound transducer. In our instrument, the database could support users in managing the result data efficiently. User programs developed using LabVIEW provide the capability to obtain precise values of the attenuation coefficient and velocity, which represent the fundamental material characteristics of the acoustic lens of the medical ultrasound transducers. The developed review program of the customized database can also search the acoustic lens information and store the experimental results.

scholarly journals A New Optical Sensor Based on Laser Speckle and Chemometrics for Precision Agriculture: Application to Sunflower Plant-Breeding

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4652
Author(s):  
Maxime Ryckewaert ◽  
Daphné Héran ◽  
Emma Faur ◽  
Pierre George ◽  
Bruno Grèzes-Besset ◽  
...  
Keyword(s):  
Precision Agriculture ◽  
Measurement Errors ◽  
Low Cost ◽  
Laser Speckle ◽  
Average Error ◽  
Accurate Information ◽  
Promising Tool ◽  
Cost Constraints ◽  
Speckle Patterns ◽  
Set Up

New instruments to characterize vegetation must meet cost constraints while providing accurate information. In this paper, we study the potential of a laser speckle system as a low-cost solution for non-destructive phenotyping. The objective is to assess an original approach combining laser speckle with chemometrics to describe scattering and absorption properties of sunflower leaves, related to their chemical composition or internal structure. A laser diode system at two wavelengths 660 nm and 785 nm combined with polarization has been set up to differentiate four sunflower genotypes. REP-ASCA was used as a method to analyze parameters extracted from speckle patterns by reducing sources of measurement error. First findings have shown that measurement errors are mostly due to unwilling residual specular reflections. Moreover, results outlined that the genotype significantly impacts measurements. The variables involved in genotype dissociation are mainly related to scattering properties within the leaf. Moreover, an example of genotype classification using REP-ASCA outcomes is given and classify genotypes with an average error of about 20%. These encouraging results indicate that a laser speckle system is a promising tool to compare sunflower genotypes. Furthermore, an autonomous low-cost sensor based on this approach could be used directly in the field.

scholarly journals Satellite-Based Personal UV Dose Estimation

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 268
Author(s):  
Todd C. Harris ◽  
Laurent Vuilleumier ◽  
Claudine Backes ◽  
Athanasios Nenes ◽  
David Vernez
Keyword(s):  
Measurement Errors ◽  
Low Cost ◽  
Public Health Research ◽  
Mobile App ◽  
Population Exposure ◽  
Dose Estimation ◽  
Annual Dose ◽  
Significant Step ◽  
Uv Dose ◽  
Dosimetry Measurement

Epidemiology and public health research relating to solar ultraviolet (UV) exposure usually relies on dosimetry to measure UV doses received by individuals. However, measurement errors affect each dosimetry measurement by unknown amounts, complicating the analysis of such measurements and their relationship to the underlying population exposure and the associated health outcomes. This paper presents a new approach to estimate UV doses without the use of dosimeters. By combining new satellite-derived UV data to account for environmental factors and simulation-based exposure ratio (ER) modelling to account for individual factors, we are able to estimate doses for specific exposure periods. This is a significant step forward for alternative dosimetry techniques which have previously been limited to annual dose estimation. We compare our dose estimates with dosimeter measurements from skiers and builders in Switzerland. The dosimetry measurements are expected to be slightly below the true doses due to a variety of dosimeter-related measurement errors, mostly explaining why our estimates are greater than or equal to the corresponding dosimetry measurements. Our approach holds much promise as a low-cost way to either complement or substitute traditional dosimetry. It can be applied in a research context, but is also fundamentally well-suited to be used as the basis for a dose-estimating mobile app that does not require an external device.

scholarly journals Real-time GNSS precise point positioning for low-cost smart devices

GPS Solutions ◽  
2021 ◽  
Vol 25 (2) ◽  
Author(s):  
Liang Wang ◽  
Zishen Li ◽  
Ningbo Wang ◽  
Zhiyu Wang
Keyword(s):  
Carrier Phase ◽  
Measurement Errors ◽  
Precise Point Positioning ◽  
Low Cost ◽  
Smart Devices ◽  
Dual Frequency ◽  
Static Mode ◽  
Phase Measurements ◽  
Positioning Errors ◽  
Point Positioning

AbstractGlobal Navigation Satellite System raw measurements from Android smart devices make accurate positioning possible with advanced techniques, e.g., precise point positioning (PPP). To achieve the sub-meter-level positioning accuracy with low-cost smart devices, the PPP algorithm developed for geodetic receivers is adapted and an approach named Smart-PPP is proposed in this contribution. In Smart-PPP, the uncombined PPP model is applied for the unified processing of single- and dual-frequency measurements from tracked satellites. The receiver clock terms are parameterized independently for the code and carrier phase measurements of each tracking signal for handling the inconsistency between the code and carrier phases measured by smart devices. The ionospheric pseudo-observations are adopted to provide absolute constraints on the estimation of slant ionospheric delays and to strengthen the uncombined PPP model. A modified stochastic model is employed to weight code and carrier phase measurements by considering the high correlation between the measurement errors and the signal strengths for smart devices. Additionally, an application software based on the Android platform is developed for realizing Smart-PPP in smart devices. The positioning performance of Smart-PPP is validated in both static and kinematic cases. Results show that the positioning errors of Smart-PPP solutions can converge to below 1.0 m within a few minutes in static mode and the converged solutions can achieve an accuracy of about 0.2 m of root mean square (RMS) both for the east, north and up components. For the kinematic test, the RMS values of Smart-PPP positioning errors are 0.65, 0.54 and 1.09 m in the east, north and up components, respectively. Static and kinematic tests both show that the Smart-PPP solutions outperform the internal results provided by the experimental smart devices.

scholarly journals Terrain Analysis of Biu Plateau, for Road Transport Development, Borno State, Nigeria

2014 ◽  
Vol 6 (2) ◽  
pp. 28
Author(s):  
Ikusemoran Mayomi ◽  
John Abdullahi ◽  
Anthony Dami
Keyword(s):  
Information Technologies ◽  
Low Cost ◽  
Road Transport ◽  
Accurate Information ◽  
Terrain Analysis ◽  
Road Transportation ◽  
Digital Elevation ◽  
Human Energy ◽  
Road Planning ◽  
Steep Slopes

Among all the means of transportation, road has been described as the most important, probably because of its flexibility and its low cost in terms of construction, maintenance and usage. However, in Nigeria, road is considered to be the most dangerous means of transportation because of their bad nature such as sharp bends, narrow bridges, steep slopes and other related problems which are associated with the terrain where these roads are constructed. Road transportation therefore needs proper planning and development through the use of geo-information technologies that would ease accessibility reduces human energy and yet brings reliable and accurate information on the terrain. In this paper, Ilwis 3.5 was used to create Digital Elevation Modelling (DEM), Shadowing, 3-Dimentional View, Slope maps and river direction maps of Biu plateau to analyze the use of GIS on road planning and development on the plateau. It was revealed that the technique has great capabilities of terrain analysis as features which are deemed humanly impossible to assess are viewed as if one is at the scene which may enhance quick analysis on road transportation. It was therefore, recommended that all the stake holders in road transportation should employ the use of this geo-information techniques in terrain analysis to ease transport planning and development in the area.

Development of the Low Cost Harmonic and Power Instrument by Using Fourier Series Method with Microcontroller

2014 ◽  
Vol 492 ◽  
pp. 519-525
Author(s):  
Napat Watjanatepin ◽  
Chaiyant Boonmee ◽  
Yutthana Kantaphayao
Keyword(s):  
Fourier Series ◽  
Power Factor ◽  
Measurement Errors ◽  
Single Phase ◽  
Low Cost ◽  
Electrical Power ◽  
Quality Measurement ◽  
Series Method ◽  
Electrical Parameters ◽  
Fourier Series Method

The objective of this paper is to present the application of microcontroller dsPIC30F6012A to measure the harmonics current and electrical power by using the Fourier series method to calculate the electrical parameters. This design is to develop the low cost harmonics instrument and to focus on working with the single phase AC system. The prototype was then developed to measure the harmonics current and power factor, and the result was compared with the standard instrument. The result is that most electrical parameters have the measurement errors of less than 4.0%. However, this idea could be developed so that it applies in the related work with the power quality measurement.

Urinalysis

Nursing OSCEs ◽  
2012 ◽  
Author(s):  
Jane Lovegrove
Keyword(s):  
Chemical Analysis ◽  
Low Cost ◽  
Microscopic Investigation ◽  
Accurate Information ◽  
Clinical Settings ◽  
Acute Care Setting ◽  
Urethral Meatus ◽  
Naked Eye ◽  
Nurse Students ◽  
Diagnostic Reagent

Urinalysis simply means analysis of urine. It is an easily performed investigation that can detect a wide variety of abnormalities within a few minutes at low cost. Urinalysis is an investigation which all nurses should be competent to perform and is identified by the NMC (2007) as being an example of an essential skill nurse students should be competent to perform before entering their branch programme. Urinalysis may be performed in a wide variety of clinical settings. It should be performed on every patient entering the acute care setting. Additionally, the National Confidential Enquiry into Patient Outcome and Death (NCEPOD (2009), stresses the need for urinalysis to be performed on all emergency admissions to an acute hospital. It may also be performed in outpatient and general practice clinics, and community areas. To obtain the most accurate information from the test, students need to know how to obtain and assess a sample of urine and be aware of factors that may influence the reliability of the investigation. Urine may be tested in three different ways. ● Macroscopic urinalysis, ● Microscopic urinalysis, ● Chemical analysis. Macroscopic and chemical analysis are the investigations performed in the clinical setting which may be tested by OSCE. Microscopic investigation requires samples to be sent to a laboratory. Macroscopic analysis is the analysis of the urine by the naked eye. Chemical analysis may be performed by use of a plastic diagnostic reagent strip or ‘dipstick’ which contains small pads of chemicals which react to substances that may be found in urine. For purposes of testing urine at random, clients are asked to urinate into a clean but not sterile dry container with no precautions regarding contamination. In females in particular this may result in samples being contaminated by vaginal fluids, such as blood or mucus. Due to the risk of contamination a mid-stream specimen of urine may be required if an abnormality is found in a random sample. A mid-stream specimen requires cleaning of the external urethral meatus prior to urination, passing the first half of the bladder contents into the lavatory, and passing the second part of the urine flow into a sterile container.

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