Improve Measurement Precision Research Articles

Gravimetric Method for Calibrating Flow Meter

What the earth obtain the energy annually is ten thousand times of the earth energy consumption at present,but the solar energy has a lower energy density on the earth’s surface .solar energy is the main source of all energy The experimental research was conducted for the heating performance utilizing the solar-assisted heat pump experimental platform. Experimental errors will be caused to flow meter by different measured media and long time usage In order to improve measurement precision and reduce the experimental errors, this test use gravimetric method to calibrate the LZB glass rotor meter and MCE08-787 cumulative flow meter of indoors and outdoors pipes. The paper also presents flow correction coefficient to guarantee both the accuracy and reliability of the experimental results.

Phase-contrast velocity mapping for highly diffusive fluids: Optimal bipolar gradient pulse parameters for hyperpolarized helium-3

In MR-velocity phase-contrast measurements, increasing the encoding bipolar gradient, i.e., decreasing the field of speed, usually improves measurement precision. However, in gases, fast diffusion during the bipolar gradient pulses may dramatically decrease the signal-to-noise ratio, thus degrading measurement precision. These two effects are contradictory. This work aims at determining the optimal sequence parameters to improve the velocity measurement precision. This work presents the theoretical optimization of bipolar gradient parameters (duration and amplitude) to improve velocity measurement precision. An analytical approximation is given as well as a numerical optimization. It is shown that the solution depends on the diffusion coefficient and T2 *. Experimental validation using hyperpolarized (3) He diluted in various buffer gases ((4) He, N2 , and SF6 ) is presented at 1.5 Tesla (T) in a straight pipe. Excellent agreement was found with the theoretical results for prediction of optimal field of speed and good agreement was found for the precision in measured velocity, but for SF6 buffered gas. The theoretical predictions were validated, providing a way to optimize velocity mapping in gases.

Object location fire precision test technology by using intersecting photoelectric detection target

To improve four across screens system measurement precision on flying projectile location, the new method that adds two incline screens to four intersecting screens system to form six intersecting screens was put forward and the flying object coordinate test model was set up. This method not only gains object coordinate but also measures object's pitching and azimuth angle that can amend coordinates and improve measurement precision. The differential methods were used to analyze their measure errors, which came from the angle of intersection screen, the thick of screen, the time and distance of measuring, and give out measure errors distributing. The experimental result shows the new measure method can improve measurement precision that meets test demand.

Test‐retest reliability of amygdala response to emotional faces

In the current study, we evaluated the test-retest reliability of amygdala response using an emotional face-matching task that has been widely used to examine pathophysiology and treatment mechanisms in psychiatric populations. Activation within the fusiform face area (FFA) was also examined. Twenty-seven healthy volunteers completed a variation of the face-matching paradigm developed by Hariri et al. (2000) at two time points approximately 90 days apart. Estimates of test-retest reliability of amygdala response to fearful faces were moderate, whereas angry and happy faces showed poor reliability. Test-retest reliability of the FFA was moderate to strong, regardless of facial affect. Collectively, these findings indicate that the reliability of the BOLD MR signal in the amygdala varies substantially by facial affect. Efforts to improve measurement precision, enlarge sample sizes, or increase the number of assessment occasions seem warranted.

Improved Interobserver Variability and Accuracy of Echocardiographic Visual Left Ventricular Ejection Fraction Assessment through a Self-Directed Learning Program Using Cardiac Magnetic Resonance Images

Although not recommended in isolation, visual estimation of echocardiographic ejection fraction (EF) is widely applied to confirm quantitative EF. However, interobserver variability for EF estimation has been reported to be as high as 14%. The aim of this study was to determine whether self-directed education could improve the accuracy and interobserver variability of visual estimation of EF and whether a multireader estimate improves measurement precision. Thirty-one participants provided single-point EF estimates for 30 echocardiograms with a spectrum of EFs, image quality, and clinical contexts in patients undergoing cardiac magnetic resonance (CMR) within 48 hours. Participants received their own case-by-case variance from CMR EF, and the 10 cases with the largest reader variability were discussed along with corresponding CMR images. Self-directed learning was undertaken by side-by-side review of echocardiographic and CMR images. Two months later, 20 new cases were shown to the same 31 participants, using the same methodology. The baseline interobserver variability of ±0.120 improved to ±0.097 after the intervention. EF misclassification (defined as ±0.05 of CMR EF) was reduced from 56% to 47% (P < .001), and the intervention also resulted in a decrease in the absolute difference between CMR and echocardiography for all cases and all readers (from 0.07 ± 0.01 to 0.06 ± 0.01, P = .0001). This improvement was most prominent for the readers with lower baseline accuracy. A combined physician-sonographer EF estimate improved the precision of EF determination by 25% compared with individual reads. In readers with varying levels of experience, a simple, mostly self-directed intervention modestly decreased interobserver variability and improved the accuracy of EF measurements. Combined physician-sonographer EF reporting improved the precision of EF estimates.

Influence of laser wavelength on the laser induced breakdown spectroscopy measurement of thin CuIn 1− xGaxSe2 solar cell films

Laser induced breakdown spectroscopy (LIBS) measurement of thin CuInxGa1−xSe2 (CIGS) films (1.2–1.9μm) with varying Ga to In ratios was carried out using the fundamental (1064nm) and second harmonic (532nm) wavelength Nd:YAG lasers (τ=5ns, spot diameter=150μm, top-hat profile) in air. The concentration ratios of Ga to In, xGa≡Ga/(Ga+In), of the CIGS samples ranged from 0.027 to 0.74 for which the band gap varied nearly proportionally to xGa from 0.96 to 1.42. It was found that the LIBS signal of 1064nm (1.17eV) wavelength laser was significantly influenced by xGa, whereas that of the 532nm (2.34eV) laser was consistent for all values of xGa. The observed dependency of the LIBS signal intensity on the laser wavelength was attributed to the large difference of photon energy of the two wavelengths that changed the absorption of incident laser energy by the film. The 532nm wavelength was found to be advantageous for multi-shot analysis that enabled depth profile analysis of the thin CIGS films and for improving measurement precision by averaging the multi-shot LIBS spectra.

Monitoring System of Battery Pack Based on PhotoMOS

To solve the problems of online monitoring system for high-voltage battery pack in series, this paper states the design of a practical interface circuit. The circuit consists of PhotoMOS, MCU and electrical switch. The PhotoMOS controlled by MCU could connect the measuring battery to measuring circuit, meanwhile the other batteries are physically isolated from the measuring circuit, and has no influence to the measuring circuit. This method effectively lowers the complexity of circuit, and improves measurement precision.

What did we learn about the Milky Way during the last decade, and what shall we learn using Gaia and LSST?

AbstractStudies of stellar populations have been reinvigorated during the last decade by the advent of large-area sky surveys such as SDSS, 2MASS, RAVE, and others. These data, together with theoretical and modeling advances, are revolutionizing our understanding of the nature of the Milky Way, and galaxy formation and evolution in general. The abundance of substructure in the multi-dimensional space of various observables, such as position, kinematics, and metallicity, is by now proven beyond doubt, and demonstrates the importance of mergers in the growth of galaxies. Unlike smooth models that involve simple components, the new data reviewed here clearly exhibit many irregular structures, such as the Sagittarius dwarf tidal stream and the Virgo and Pisces overdensities in the halo, and the Monoceros stream closer to the Galactic plane. These recent developments have made it clear that the Milky Way is a complex and dynamic structure, one that is still being shaped by the merging of neighboring smaller galaxies. Here we summarize developments over the last decade in our mapping of the stellar content of the Milky Way, as well as recent attempts to map the dark matter halo by Loebman et al. (2012) and ISM dust distribution by Berry et al. (2012). We also briefly discuss the next generation of wide-field sky surveys, exemplified by Gaia and LSST, which will improve measurement precision manyfold, and comprise billions of individual stars.

Single-photon pulsed-light indirect time-of-flight 3D ranging

"Indirect" time-of-flight is one technique to obtain depth-resolved images through active illumination that is becoming more popular in the recent years. Several methods and light timing patterns are used nowadays, aimed at improving measurement precision with smarter algorithms, while using less and less light power. Purpose of this work is to present an indirect time-of-flight imaging camera based on pulsed-light active illumination and a 32 × 32 single-photon avalanche diode array with an improved illumination timing pattern, able to increase depth resolution and to reach single-photon level sensitivity.

Special Display Instrument for Fiber Current Transformer

To meet the requirement of fiber current transformer, special display instrument was deigned. SCM and advanced signal process technology were adopted in the instrument, so that the output voltage signal of low voltage terminal can be utilized by instrument to display measured busbar current value real-time. Besides, section linearization and distinguish calibration methods were adopted to improve measurement precision of display instrument. The experiment results indicated that this instrument has virtues of reliability, high precision and low cost, importantly, it can come up to the 0.2 standard. So we can draw a conclusion that this instrument can meet the industrial requirement for display instrument.

The case for an international patient-reported outcomes measurement information system (PROMIS®) initiative

Patient-reported outcomes (PROs) play an increasingly important role in clinical practice and research. Modern psychometric methods such as item response theory (IRT) enable the creation of item banks that support fixed-length forms as well as computerized adaptive testing (CAT), often resulting in improved measurement precision and responsiveness. Here we describe and discuss the case for developing an international core set of PROs building from the US PROMIS® network.PROMIS is a U.S.-based cooperative group of research sites and centers of excellence convened to develop and standardize PRO measures across studies and settings. If extended to a global collaboration, PROMIS has the potential to transform PRO measurement by creating a shared, unifying terminology and metric for reporting of common symptoms and functional life domains. Extending a common set of standardized PRO measures to the international community offers great potential for improving patient-centered research, clinical trials reporting, population monitoring, and health care worldwide. Benefits of such standardization include the possibility of: international syntheses (such as meta-analyses) of research findings; international population monitoring and policy development; health services administrators and planners access to relevant information on the populations they serve; better assessment and monitoring of patients by providers; and improved shared decision making.The goal of the current PROMIS International initiative is to ensure that item banks are translated and culturally adapted for use in adults and children in as many countries as possible. The process includes 3 key steps: translation/cultural adaptation, calibration, and validation. A universal translation, an approach focusing on commonalities, rather than differences across versions developed in regions or countries speaking the same language, is proposed to ensure conceptual equivalence for all items. International item calibration using nationally representative samples of adults and children within countries is essential to demonstrate that all items possess expected strong measurement properties. Finally, it is important to demonstrate that the PROMIS measures are valid, reliable and responsive to change when used in an international context.IRT item banking will allow for tailoring within countries and facilitate growth and evolution of PROs through contributions from the international measurement community. A number of opportunities and challenges of international development of PROs item banks are discussed.

Exploration in Adjustment of AC Electric Bridge

One method called “low-order digit decided by high-order digit” is introduced to be applied to equilibrate AC electric bridge with two adjustable parameters frequently encountered in college physics experiment. The full verification of this method is discussed intuitionally. It is indicated that one can eliminate some disturbance of noise and improve measurement precision by using this method.

Design and Study of Resistance Wave Height Meter

This paper introduces the design principles for the resistance wave height meter and structure of hardware and software, madding brief elaborate on the functions and realization of each module. The system adopts a compensating lever method to exclude the impact of the solution conductivity on the system measurement results. The excitation source use bipolar pulse voltage, easing the dielectric polarization problem, so that the circuit is further simplified, improves measurement precision.

Design of Portable Instrument for the Concentration of Potassium Ions in Human Vitreous Humor to Estimate the Postmortem Interval

This paper presents a portable measurement system for the concentration of potassium ions in human vitreous humor. This system mainly consists of three units, which are ion selective electrode, STC89C52 microcontroller and 16-bit AD7705 analog-to-digital convertor. In order to improve measurement precision, temperature compensation was conducted by using DS18B20 temperature sensor to detect ambient temperature and processing data with compensation measures. This system was tested with potassium solution and the precision can reach up to 99.69%. It can measure in situ the concentration of potassium ions in human vitreous humor which can be used to estimate the postmortem interval. The measuring system presented in this paper is easy to operate and can also measure other ions by changing ISE and the value of feedback resistor of operational amplifier.

Galactic Stellar Populations in the Era of the Sloan Digital Sky Survey and Other Large Surveys

Studies of stellar populations, understood to mean collections of stars with common spatial, kinematic, chemical, and/or age distributions, have been reinvigorated during the past decade by the advent of large-area sky surveys such as the Sloan Digital Sky Survey, the Two-Micron All Sky Survey, the Radial Velocity Experiment, and others. We review recent analyses of these data that, together with theoretical and modeling advances, are revolutionizing our understanding of the nature of the Milky Way and galaxy formation and evolution in general. The formation of galaxies like the Milky Way was long thought to be a steady process leading to a smooth distribution of stars. However, the abundance of substructure in the multidimensional space of various observables, such as position, kinematics, and metallicity, is now proven beyond doubt and demonstrates the importance of mergers in the growth of galaxies. Unlike smooth models that involve simple components, the new data reviewed here clearly exhibit many irregular structures, such as the Sagittarius dwarf tidal stream and the Virgo and Pisces overdensities in the halo and the Monoceros stream closer to the Galactic plane. These recent developments have made it clear that the Milky Way is a complex and dynamic structure, one that is still being shaped by the merging of neighboring smaller galaxies. We also briefly discuss the next generation of wide-field sky surveys, such as SkyMapper, Panoramic Survey Telescope &amp; Rapid Response System, Global Astrometric Interferometer for Astrophysics, and the Large Synoptic Survey Telescope, which will improve measurement precision manyfold and include billions of individual stars. The ultimate goal, development of a coherent and detailed story of the assembly and evolutionary history of the Milky Way and other large spirals like it, now appears well within reach.

Internal Multiple-Scattering Hole-Enhanced Raman Spectroscopy: Improved Backscattering Fourier Transform Raman Sampling in Pharmaceutical Tablets Utilizing Cylindrical–Conical Holes

The benefits of Raman signal enhancement and improved measurement precision are demonstrated using 180° backscattering Fourier transform Raman (FT-Raman) spectroscopy from drilled cylindrical-conical holes within pharmaceutical tablet cores. Multiple scattering of the incident laser light within the holes results in an increased Raman signal due to the larger Raman sampling volume. This is important for overcoming typical sub-sampling issues encountered when employing FT-Raman backscattering of heterogeneous pharmaceutical tablets. Hole depth and diameter were found to be important experimental parameters and were optimized to yield the greatest signal enhancement. The FT-Raman spectra collected using backscattering from cylindrical-conical holes is compared to typical 180° backscattering from flat surfaces using tablet cores of Excedrin® and Vivarin®. Raman chemical images are used to establish a representative sampling area. We observe a three- to five-fold increase in the Raman intensity and a two-fold improvement in the measurement precision when sampling from cylindrical-conical holes rather than classic backscattering from flat tablet cores. Self-absorption effects on analyte band ratios are negligible in the fingerprint region but are more significant at the higher near-infrared (NIR) absorbances found in the C-H/O-H/-N-H stretching region. The sampling technique will facilitate developing quantitative FT-Raman methods for application to pharmaceutical tablets using the fingerprint spectral region.

Resolution of Acute Pain Following Discharge From the Emergency Department: The Acute Pain Trajectory

We demonstrate and evaluate a method for modeling acute pain resolution in individual patients over 6 days following an emergency department visit for an acutely painful condition. Five hundred and thirteen patients presenting with acutely painful conditions provided 11-point numerical ratings of pain intensity at discharge from an emergency department and daily thereafter for a total of 6 days. Latent growth curve modeling with a linear fit yielded measures of initial pain intensity (intercept) and rate of pain resolution (slope) for each individual patient. The linear fits provided good approximations of individual pain trajectories. The average patient had intercept of 6.57 with a slope of −.61. On Day 4, 54.6% of patients reported a pain level equal to or greater than 4. Classification of individual patients by slope revealed that 79% of the sample had the expected negative slope for acute pain resolution while 21% had flat or positive slopes, indicating lack of pain resolution or worsening of pain over time following discharge. The standard errors of measurement for the acute pain trajectories were markedly smaller than those for conventional pain ratings, indicating that the trajectory approach to pain measurement improves measurement precision. PerspectiveThe acute pain trajectory provides more information than conventional pain measurement and increases measurement precision. It provides a means of determining the efficacy of acute pain management in the emergency department. The rate of pain resolution is a potentially valuable outcome measure for controlled clinical trials.

Improving the Accuracy and Precision of Cognitive Testing in Mild Dementia

The CAMCOG, ADAS-cog, and MMSE, designed to grade global cognitive ability in dementia have inadequate precision and accuracy in distinguishing mild dementia from normal ageing. Adding neuropsychological tests to their scale might improve precision and accuracy in mild dementia. We, therefore, pooled neuropsychological test-batteries from two memory clinics (ns = 135 and 186) with CAMCOG data from a population study and 2 memory clinics (n = 829) and ADAS-cog data from 3 randomized controlled trials (n = 713) to estimate a common dimension of global cognitive ability using Rasch analysis. Item difficulties and individuals' global cognitive ability levels were estimated. Difficulties of 57 items (of 64) could be validly estimated. Neuropsychological tests were more difficult than the CAMCOG, ADAS-cog, and MMSE items. Most neuropsychological tests had difficulties in the ability range of normal ageing to mild dementia. Higher than average ability levels were more precisely measured when neuropsychological tests were added to the MMSE than when these were measured with the MMSE alone. Diagnostic accuracy in mild dementia was consistently better after adding neuropsychological tests to the MMSE. We conclude that extending dementia specific instruments with neuropsychological tests improves measurement precision and accuracy of cognitive impairment in mild dementia.

Dynamic Control of Adsorption Sensitivity for Photo-EMF-Based Ammonia Gas Sensors Using a Wireless Network

This paper proposes an adsorption sensitivity control method that uses a wireless network and illumination light intensity in a photo-electromagnetic field (EMF)-based gas sensor for measurements in real time of a wide range of ammonia concentrations. The minimum measurement error for a range of ammonia concentration from 3 to 800 ppm occurs when the gas concentration magnitude corresponds with the optimal intensity of the illumination light. A simulation with LabView-engineered modules for automatic control of a new intelligent computer system was conducted to improve measurement precision over a wide range of gas concentrations. This gas sensor computer system with wireless network technology could be useful in the chemical industry for automatic detection and measurement of hazardous ammonia gas levels in real time.

Ultrasonic characterization of a fluid layer using a broadband transducer

A measurement method is proposed for the ultrasonic characterization of a fluid layer, corresponding to the resin transfer molding (RTM) manufacturing process. The ultrasonic velocity and attenuation of the silicone oil are measured in three samples having different viscosities. The measurement method is established on the basis of the attenuation of ultrasonic waves in fluids. A correction of the beam diffraction is implemented to improve measurement precision. A single element transducer with central frequency of 15 MHz is used. The tested fluids simulate the industrial resin used to manufacture composite materials. When injecting this resin, its viscosity increases until it reaches a critical state of polymerization. In this paper we focus on ultrasonic characterization of three fluids representing three intermediate cases of fluid resin during its injection before reaching the polymerization state.