23 resultados para Quality Index
Resumo:
In this paper, we use ARIMA modelling to estimate a set of characteristics of a short-term indicator (for example, the index of industrial production), as trends, seasonal variations, cyclical oscillations, unpredictability, deterministic effects (as a strike), etc. Thus for each sector and product (more than 1000), we construct a vector of values corresponding to the above-mentioned characteristics, that can be used for data editing.
Resumo:
The present research is focused on the application of hyperspectral images for the supervision of quality deterioration in ready to use leafy spinach during storage (Spinacia oleracea). Two sets of samples of packed leafy spinach were considered: (a) a first set of samples was stored at 20 °C (E-20) in order to accelerate the degradation process, and these samples were measured the day of reception in the laboratory and after 2 days of storage; (b) a second set of samples was kept at 10 °C (E-10), and the measurements were taken throughout storage, beginning the day of reception and repeating the acquisition of Images 3, 6 and 9 days later. Twenty leaves per test were analyzed. Hyperspectral images were acquired with a push-broom CCD camera equipped with a spectrograph VNIR (400–1000 nm). Calibration set of spectra was extracted from E-20 samples, containing three classes of degradation: class A (optimal quality), class B and class C (maximum deterioration). Reference average spectra were defined for each class. Three models, computed on the calibration set, with a decreasing degree of complexity were compared, according to their ability for segregating leaves at different quality stages (fresh, with incipient and non-visible symptoms of degradation, and degraded): spectral angle mapper distance (SAM), partial least squares discriminant analysis models (PLS-DA), and a non linear index (Leafy Vegetable Evolution, LEVE) combining five wavelengths were included among the previously selected by CovSel procedure. In sets E-10 and E-20, artificial images of the membership degree according to the distance of each pixel to the reference classes, were computed assigning each pixel to the closest reference class. The three methods were able to show the degradation of the leaves with storage time.
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InsideFood explicitly aims at measuring food microstructure, the spatial distribution of food components within foods, with state of the art tomographic, spectroscopic and texture measurement techniques including X-ray micro-and nano CT, MRI,OCT, NMR, TRS and SRS, and acoustic emission. Nutritional quality (sugar and gluten free cereal products), sensory quality (texture of all foods) and safety (foreign material detection in cereal products) are considered. Online and inline techniques including NMR, MRI, TRS, SRS and X-ray imaging to visualise and monitor structure will be developed.
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Two experiments were conducted to determine the influence of duration of storage of soybean meal (SBM) on variables that define the quality of the protein fraction. Urease activity, protein dispersibility index (PDI), KOH protein solubility (KOHsol), and trypsin inhibitor activity were determined. In experiment 1, 8 samples of SBM, ranging in CP content from 55.4 to 56.5% DM, were collected from a US crushing plant at weekly intervals and analyzed at arrival to the laboratory and after 30, 60, 90, and 120 d of storage. In experiment 2, 7 samples of SBM, ranging in CP content from 49.0 to 55.0% DM, were collected from different Argentinean crushers and analyzed at arrival and after 24, 48, 80, and 136 wk of storage. In both experiments, samples were stored in hermetic glass containers in a laboratory room at 12 ± 2°C and a relative humidity of 70 ± 3%. Duration of storage did not affect urease activity or trypsin inhibitor activity values in either of the 2 experiments. However, PDI values decreased linearly with time of storage in both experiments (P menor que 0.001). Also, KOHsol decreased linearly (P menor que 0.05) with duration of storage in experiment 2 (long-term storage) but not in experiment 1(shorter term storage). Therefore, PDI values might not be adequate to compare protein quality of commercial SBM samples that have been stored for different periods of time. The KOHsol values are less affected by length of storage of the meals under current commercial practices.
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Material Culture and Quality of Urban Life
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This work proposes an optimization of a semi-supervised Change Detection methodology based on a combination of Change Indices (CI) derived from an image multitemporal data set. For this purpose, SPOT 5 Panchromatic images with 2.5 m spatial resolution have been used, from which three Change Indices have been calculated. Two of them are usually known indices; however the third one has been derived considering the Kullbak-Leibler divergence. Then, these three indices have been combined forming a multiband image that has been used in as input for a Support Vector Machine (SVM) classifier where four different discriminant functions have been tested in order to differentiate between change and no_change categories. The performance of the suggested procedure has been assessed applying different quality measures, reaching in each case highly satisfactory values. These results have demonstrated that the simultaneous combination of basic change indices with others more sophisticated like the Kullback-Leibler distance, and the application of non-parametric discriminant functions like those employees in the SVM method, allows solving efficiently a change detection problem.
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As the world becomes more urbanised, public transport in cities must seek to provide viable alternatives to individual car transport. At an urban level, interchanges in public transport networks provide easy transfers between and within different transport modes and facilitate seamless travel. This study proposes a methodological framework with which to identify the factors that travellers view as key elements of an urban transport interchange. An attitudinal survey was undertaken in order to collect information about users? needs and perceptions in the Moncloa interchange in Madrid, Spain. The results obtained from an Importance-Performance Analysis (IPA) show that aspects related to the signposting of different facilities and transport services, the internal design of the interchange and the surrounding area, and safety and security are the greatest strengths of the interchange.
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The study of service quality and its implication for transport contracts has several approaches in research and practical applications, where the main emphasis is the consideration of quality from the user's point of view, thus obtaining a customer satisfaction index as a measurement of the overall quality with no further implications for service providers. The main aim of this paper is to estimate the real economic impact of improving quality attributes for a bus operator. An application of the activity-based costing methodology is developed for a bus contract in Madrid, using quality data from surveys together with economic and performance information, and focusing on headway as a quality variable. Results show the consistency and practicality of this methodology, overcoming simplifications from traditional procedures. This method is a powerful tool in quality-based contracting as well as for effective investment in transport quality under poverty funding constraints