Calibration Research Papers - Academia.edu (original) (raw)

A new procedure for the calibration of an articulated arm coordinate measuring machine (AACMM) is presented in this paper. First, a self-calibration algorithm of four laser trackers (LTs) is developed. The spatial localization of a... more

A new procedure for the calibration of an articulated arm coordinate measuring machine (AACMM) is presented in this paper. First, a self-calibration algorithm of four laser trackers (LTs) is developed. The spatial localization of a retroreflector target, placed in different positions within the workspace, is determined by means of a geometric multilateration system constructed from the four LTs. Next, a nonlinear optimization algorithm for the identification procedure of the AACMM is explained. An objective function based on Euclidean distances and standard deviations is developed. This function is obtained from the captured nominal data (given by the LTs used as a gauge instrument) and the data obtained by the AACMM and compares the measured and calculated coordinates of the target to obtain the identified model parameters that minimize this difference. Finally, results show that the procedure presented, using the measurements of the LTs as a gauge instrument, is very effective by ...

This paper presents a non-intrusive system that gives the illusion of a 3D immersive and interactive environment with 2D projectors. The user does not need to wear glasses, nor to watch a (limited) screen. The virtual world is all around... more

This paper presents a non-intrusive system that gives the illusion of a 3D immersive and interactive environment with 2D projectors. The user does not need to wear glasses, nor to watch a (limited) screen. The virtual world is all around him, drawn on the floor. As the user is himself immersed in the virtual world, there is no need for a proxy like an avatar; he can move inside the virtual environment freely. Moreover, the I-see-3D system allows a user to manipulate virtual objects with his own body, making interactions with the virtual world very intuitive. Giving the illusion of 3D requires to render images in such a way that the deformation of the image projected on the floor is taken into account, as well as the position of the user’s “eye” in its virtual world. The resulting projection is neither perspective nor orthographic. Nevertheless, we describe how this can be implemented with the standard OpenGL pipeline, without any shader. Our experiments demonstrate that our system i...

Interest in the development of functions that estimate the likelihood of an individual suffering a future cardiovascular disease (CVD) event has increased in recent times (e.g. Framingham sheets, SCORE-Systematic COronary Risk Estimation,... more

Interest in the development of functions that estimate the likelihood of an individual suffering a future cardiovascular disease (CVD) event has increased in recent times (e.g. Framingham sheets, SCORE-Systematic COronary Risk Estimation, PROCAM, etc.). However, the estimates of absolute risk may show substantial variations between different populations, because of geographical, cultural, social, behavioural and genetic differences, as well as various methodological issues related to the predictive models employed. We sought to calibrate the SCORE equations to the Greek population. We used the SCORE system that offers an estimation of total fatal CVD risk in "high" and "low" CVD risk European countries. The project pulls together a pool of datasets from 12 European countries and 2.7 million person-years of observation. A mathematical procedure to adjust the risk estimates for individual countries was applied, based on local mortality and risk factor prevalence da...

Summary. A precise and sensitive chromogenic assay for the measurement of very low levels of factor VIII (FVIII) in plasma has been developed. The assay is based on modifications of a commercially available chromogenic assay. The... more

Summary. A precise and sensitive chromogenic assay for the measurement of very low levels of factor VIII (FVIII) in plasma has been developed. The assay is based on modifications of a commercially available chromogenic assay. The modifications include reduction of sample final dilution factor and prolongation of the development period. The modified assay allows accurate and precise measurement of FVIII in the range of 0.001–0.02 IU mL−1. The detection limit is 0.0005 IU mL−1 and the quantitation limit is 0.0015 IU mL−1. This assay can be used in research and to study the clinical efficacy of low circulating levels of FVIII in haemophilia A patients.

Classically, the end point detection during fluid bed drying has been performed using indirect parameters, such as the product temperature or the humidity of the outlet drying air. This paper aims at comparing those classic methods to... more

Classically, the end point detection during fluid bed drying has been performed using indirect parameters, such as the product temperature or the humidity of the outlet drying air. This paper aims at comparing those classic methods to both in-line moisture and solid-state determination by means of Process Analytical Technology (PAT) tools (Raman and NIR spectroscopy) and a mass balance approach. The six-segmented fluid bed drying system being part of a fully continuous from-powder-to-tablet production line (ConsiGma™-25) was used for this study. A theophylline:lactose:PVP (30:67.5:2.5) blend was chosen as model formulation. For the development of the NIR-based moisture determination model, 15 calibration experiments in the fluid bed dryer were performed. Six test experiments were conducted afterwards, and the product was monitored in-line with NIR and Raman spectroscopy during drying. The results (drying endpoint and residual moisture) obtained via the NIR-based moisture determinati...

Fuzzy Logic has been proposed for information representation and manipulation in databases, being the current tendency to study mechanisms of flexible querying to traditional databases. SQLf has been one of the efforts in this tendency.... more

Fuzzy Logic has been proposed for information representation and manipulation in databases, being the current tendency to study mechanisms of flexible querying to traditional databases. SQLf has been one of the efforts in this tendency. On the other hand, there are many different dialects of SQL. There are two major standards: ANSI (American National Standards Institute) SQL and an updated

A sensitive and specific HPLC–ESI-MS/MS method for the direct determination of glucosamine in human plasma has been developed and validated. Plasma samples were analyzed after a simple, one-step protein precipitation clean-up with... more

A sensitive and specific HPLC–ESI-MS/MS method for the direct determination of glucosamine in human plasma has been developed and validated. Plasma samples were analyzed after a simple, one-step protein precipitation clean-up with trichloroacetic acid using a polymer-based amino high-performance liquid chromatography (HPLC) column and a water/acetonitrile mobile phase elution gradient, with d-[1-13C]glucosamine as the internal standard. Detection was performed by mass spectrometry, using an electrospray source and employing multiple reaction monitoring to separately monitor glucosamine and the internal standard. The limit of quantification of the method was 10 ng/ml of glucosamine and the calibration curve showed a good linearity up to 1000 ng/ml. The precision (R.S.D.) and the accuracy (bias) of the method at the limit of quantification were 13.8 and 4.0%, respectively, and the mean recovery of glucosamine at three concentration levels was 101.6 ± 5.7%. The method was applied for the determination of glucosamine concentrations in human plasma samples collected from untreated healthy volunteers and, in a separate bioavailability study, to evaluate plasma glucosamine pharmacokinetics profiles after oral administration of crystalline glucosamine sulfate.

Thermal cameras are used in research laboratories to measure tissue temperature during laser irradiation. This study was an evaluation of the accuracy of a 3–5 μm thermal camera and two 8–12 μm cameras in detecting the maximum... more

Thermal cameras are used in research laboratories to measure tissue temperature during laser irradiation. This study was an evaluation of the accuracy of a 3–5 μm thermal camera and two 8–12 μm cameras in detecting the maximum temperatures of small targets. The size of the targets was within the range of laser spot diameters which are used for vessel welding, angioplasty, and dermatology. The response to a sharp thermal edge was measured and analyzed for the three cameras, which had a scanning rate of 30 frames per second. The response of the 3–5 μm camera to reference black body targets of different sizes was also studied.It was found that the detector system required an average of 2.44 μs to reach 90% of maximum step response for the 8–12 μm system and 5.85 μs for the 3–5 μm system. With a 3×5 telescope and a 9.5 inch focal distance close-up lens, the 3–5 μm camera underestimated the temperature of targets smaller than 2.0 mm because of its slow detector response. Although the 8–12 μm camera provides more accurate measurements due to its faster detector response, it still underestimates the temperature of targets smaller than 900 μm, when similar magnification and focal distance are used.Methods to compensate for the inaccuracies are discussed, including empirical correction factors and the inverse filtering technique.

Abstract. Donation payment mechanisms are well suited for some contingent valuation studies. In an effort to better understand the discrepancy that has been consistently found between actual and hypothetical donations, we investigate an... more

Abstract. Donation payment mechanisms are well suited for some contingent valuation studies. In an effort to better understand the discrepancy that has been consistently found between actual and hypothetical donations, we investigate an approach to estimating actual ...

Interaction thermodynamics between warfarin, a very popular anticoagulant, and Sudlow I binding site of human (HSA) or bovine (BSA) serum albumin have been examined in strictly controlled experimental conditions (HEPES buffer 50 mM, pH... more

Interaction thermodynamics between warfarin, a very popular anticoagulant, and Sudlow I binding site of human (HSA) or bovine (BSA) serum albumin have been examined in strictly controlled experimental conditions (HEPES buffer 50 mM, pH 7.4 and 25 °C) by means of isothermal titration calorimetry (ITC), fluorescence spectrometry (FS) and frontal analysis capillary electrophoresis (FA/CE). Each technique is based on measurements of a different property of the biochemical system, and then the results allow a critical discussion about the suitability of each approach to estimate the drug-protein binding parameters. The strongest interaction step is properly evaluated by the three assayed approaches being the derived binding constants strongly consistent: from 4 × 104 to 7 × 104 for HSA and from 0.8 × 105 to 1.2 × 105 for BSA. Binding enthalpy variations also show consistent results: -5.4 and -5.6 Kcal/mol for HSA and -4.3 and -3.7 Kcal/mol for BSA, as measured by ITC and FS, respectively...

Colour is the first attribute subject to consumer perception in determining food quality and, in many cases, this is the only possible mean to qualify product at purchase. For this reason, the description of colour by analytical methods... more

Colour is the first attribute subject to consumer perception in determining food quality and, in many cases, this is the only possible mean to qualify product at purchase. For this reason, the description of colour by analytical methods is fundamental in food processing control. Computer vision systems acquire RGB data which are device-dependent and sensitive to the different lightning. Therefore, they are not directly useful for colour evaluation to mimic human vision. On the contrary, traditional colorimeters, which adopt CIELab coordinates, work in human-oriented colour space where euclidean distance between two different colours (∆E) is well related to the difference perceived by human sight. Nevertheless, vision systems have many advantages as the capability of acquiring larger areas of the food surface and the easiness of implementation in automated plants at low costs. Neural networks, trained on a set of selected colour samples, can approximate RGB to L*a*b* relationships to characterise the colour of food samples under test. The aim of this paper is to present a rapid method based on neural networks for the calibration of a CCD (Charge-Coupled Device) camera colour acquisition system to obtain reliable L*a* b* information. Preliminary results concerning the influence of the composition of the training test and the camera settings (aperture and time of exposure) on the reliability and accuracy of the colour measurement system are also discussed.