Matrix factorizations for quantum complete intersections

We introduce twisted matrix factorizations for quantum complete intersections of codimension two. For such an algebra, we show that in a given dimension, almost all the indecomposable modules with bounded minimal projective resolutions correspond to such matrix factorizations.Comment: 13 page

Determining wood chip size: image analysis and clustering methods

One of the standard methods for the determination of the size distribution of wood chips is the oscillating screen method (EN 15149- 1:2010). Recent literature demonstrated how image analysis could return highly accurate measure of the dimensions defined for each individual particle, and could promote a new method depending on the geometrical shape to determine the chip size in a more accurate way. A sample of wood chips (8 litres) was sieved through horizontally oscillating sieves, using five different screen hole diameters (3.15, 8, 16, 45, 63 mm); the wood chips were sorted in decreasing size classes and the mass of all fractions was used to determine the size distribution of the particles. Since the chip shape and size influence the sieving results, Wang’s theory, which concerns the geometric forms, was considered. A cluster analysis on the shape descriptors (Fourier descriptors) and size descriptors (area, perimeter, Feret diameters, eccentricity) was applied to observe the chips distribution. The UPGMA algorithm was applied on Euclidean distance. The obtained dendrogram shows a group separation according with the original three sieving fractions. A comparison has been made between the traditional sieve and clustering results. This preliminary result shows how the image analysis-based method has a high potential for the characterization of wood chip size distribution and could be further investigated. Moreover, this method could be implemented in an online detection machine for chips size characterization. An improvement of the results is expected by using supervised multivariate methods that utilize known class memberships. The main objective of the future activities will be to shift the analysis from a 2-dimensional method to a 3- dimensional acquisition process

Design for limit stresses of orange fruits (Citrus sinensis) under axial and radial compression as related to transportation and storage design

This article employed the Hertz contact stress theory and the finite element method to evaluate the maximum contact pressure and the limit stresses of orange fruit under transportation and storage. The elastic properties of orange fruits subjected to axial and axial contact were measured such that elastic limit force, elastic modulus, Poisson’s ratio and bioyield stress were obtained as 18 N, 0.691 MPa, 0.367, 0.009 MPa for axial compression and for radial loading were 15.69 N, 0.645 MPa, 0.123, 0.010 MPa. The Hertz maximum contact pressure was estimated for axial and radial contacts as 0.036 MPa. The estimated limiting yield stress estimated as von Mises stresses for the induced surface stresses of the orange topologies varied from 0.005 MPa–0.03 MPa. Based on the distortion energy theory (DET) the yield strength of orange fruit is recommended as 0.03 MPa while based on the maximum shear stress theory (MSST) is 0.01 MPa for the design of orange transportation and storage system

Morphological variation on tomato leaves due to different nitrogen contents

Elliptic Fourier Analysis (EFA) is a method used to quantify shape differences.  It mathematically describes the entire shape of an object by transforming the contour into Fourier coefficients, used as variables for statistical analysis, and involving the fitting of some type of curve to the object outline.  Generally, the shape of agricultural products such as fruit, vegetables, grain and in addition other organs of plant is one of the most important factors for their classification and grading in relation to commercial quality and organoleptic properties.  The aim of this study is to quantify the morphological variation of the shape of tomato leaves in response to their different nitrogen (N) content using the EFA coefficients, the fractal geometry and the perimeter ratio in combination with the Partial Least Squares Discriminant Analysis (PLS-DA).  The analyses were realized on a tomato crop where each sample was chemically analyzed at the laboratory to establish the N content.  The leaves (168) were divided into 3 groups following different N concentrations.  Results suggest no relation between leaves lengths and N concentration is present following the Kruskal-Wallis performed with a p=0.735.  The PLS-DA performing on the EFA coefficients, fractal index and perimeter ratio shows a high sensitivity, sensibility, and reduced mean classification error (82.3%, 81.07% and 18.3% respectively).  The percentages of the correct classification in the model resulted to be 69.29% while the independent test equal to 56.1%.  This study demonstrated the relation between leaf shape and N content (expressed in 3 concentration groups).Keywords: Tomato leaf, elliptic Fourier analysis, fractal index, perimeter ratio, partial least squares discriminant analysis

Intermodal vs. conventional logistic of refrigerated products: a case study from Southern to Northern Europe

Most of perishable goods, such as fruit and vegetables, are transported in Europe by truck and clogging up the main road networks. The increasing demand for freight transport and the environmental concerns all indicate the necessity to embrace new means of transport such as the intermodal one. The intermodal transport uses swap bodies and reefer containers that allow for the use of interchangeable truck, train, and ship to reduce direct and external costs. Nowadays, the utilization of exclusive truck transport is due to its considerable flexibility and often to the disregard of the motor vehicle regulations during transport. This research aims to analyze some essential readjustments that must be made in order to increase efficiency in the logistic of refrigerated fruit and vegetables. To do so, some hypotheses were analyzed and formulated in which the strategic use of the truck was recognized and inserted as part of an intermodal transport system. The transport options of a combined use of ships and trains in association with trucks were evaluated with respect to the current prevalent solution of exclusive use of trucks. Such options were evaluated by comparing them under different itineraries hypotheses (from south Italy, Sicily to Germany, Munich) on the base of costs and transit-times parameters. This was done mainly throughout interviewing sector-relevant transport operators. The results of the comparison between the intermodal and conventional transport was shown to be economically more convenient with respect to both legal and illegal transport by exclusive truck transport, presenting lower per unit costs (swap body or semi-trailer, containing the same amount of goods). Moreover, the intermodal solution scores equal or higher transit times in the comparison with the “transit by regulation compliance” and much higher transit times if compared with the “illegal” option. Therefore, the regulation compliance aspect would partially promote the use of intermodal options in a future fair competition. In addition, besides reducing the direct costs, it produces several other positive effects in terms of external costs to the society such as to reduce road crashes, noises, atmospheric emissions and greenhouse effect. A more efficient system should plan an integrated system of arrival and departure organizing together the schedules of ships and trains dedicated to perishable goods and increasing the transported amounts. Furthermore, another idea is to stipulate commercial agreements with train operators, applying a reduction on the base price, by ensuring the delivery of a block train for an arranged period.   Keywords: Intermodal, freight logisticcentre, truck haulage, rail hub; terminal

Neinvazivna metoda za utvrđivanje organski gajene ribe

U poslednjih nekoliko godina, prisutne su drugačije tendencije u akvakulturi, koje pre svega imaju za cilj plasiranje novih proizvoda, od kojih je jedan i riba gajena u organskoj akvakulturi. Razlikovanje ribe gajene u organskoj akvakulturi od one gajene na konvencionalni način je teško, ali se razlika može napraviti preko njenog izgleda. U ovom eksperimentu brancin je hranjen konvencionalnom i organskom hranom i u toku gajenja, pravljene su fotografije primeraka. Nakon kalibracije boje, određene su merne tačke na svakoj fotografiji, a nakon toga su geometrijskim i morfometrijskim metodama dobijene RGB matrice. Tako dobijena matrica (195x135,225) je prvobitno analizirana korišćenjem 50-50 MANOVA metode, a nakon toga su urađeni diskriminantna analiza i na kraju dendrogram. Svi uzorci su klasifikovani korišćenjem tri diskriminantna modela. Tako je dendrogram sa ukupno 9 različitih klasa pokazao da se ribe koje su gajene u organskoj akvakulturi slične ribama uzorkovanim iz prirodnih populacija. Rezultati su pokazali i da dve grupe riba, hranjenih različitim komercijalnim hranama u ovom eksperimentu, jedne u organskoj, a druge u konvencionalnoj akvakulturi mogu biti prepoznate po boji njihovog tela. Šta više, što duže vremena ribe provedu u jednom od ova dva načina gajenja, to se boja njihovog tela više razlikuje. Deo tela koji pokazuje najveće promene u boji jeste glava, koja je značajno svetlije boje u grupi riba gajenih u organskoj akvakulturi. Tako je dokazano da analiza boje tela može biti iskorišćena za razlikovanje riba koje su gajene u drugačijim uslovima korišćenjem različitih protokola i načina gajenja. Međutim, ovaj zaključak se može primeniti samo na ove, konkretne podatke, ne može biti generalizovan i ne može se primeniti na sve ribe gajene u organskoj akvakulturi

An Advanced Colour Calibration Method for Fish Freshness Assessment: a Comparison Between Standard and Passive Refrigeration Modalities

Freshness represents a pivotal aspect in fish product for both security and quality. Its evaluation still represents the key factor driving the consumer' choices. Fish appearance is affected by many different factors that demand the contribution of different disciplines to be understood: from the physical and optical properties to the slaughtering and post-slaughtering conditions. An innovative preservation system is represented by the Passive Refrigeration PRS (TM) developed for the preservation and transport of perishable food products. Scientific methods for product freshness evaluation may be conveniently divided into two categories: sensorial and instrumental. In this study, an instrumental method of colour calibration and discrimination is proposed at pilot scale for automatic evaluation of gilthead seabream (Sparus aurata) freshness. We propose a non-destructive method based on the colorimetric imaging of the whole external body of seabreams to evaluate through multivariate partial least squares which approach the differences in the freshness preservation under four refrigeration modalities. The matrix of the independent variables is represented by RGB values for each pixel belonging to an extracted region of interest (129,633 values). The dependent variable is composed by two dummy variable corresponding to fresh (T-0) or non-fresh (T-2) individuals. T-1 individuals were used as external test. The results quantified significant colorimetric differences between fresh and non-fresh fish. All fish used to create the model (T-0 and T-2) were correctly classified as fresh or non-fresh, while external test individuals (T-1) were all classified as fresh. The proposed imaging method merges different image analysis techniques: (a) colorimetric calibration, (b) morphometric superimposition and (c) partial least square discriminant analysis modelling. This innovative and non-destructive approach allows the automatic assessment of fish freshness

Multivariate forecasting model to optimize management of grape downy mildew control

Aim of this study was to develop a forecasting model for Plasmopara viticola to achieve rational disease management and to reduce the use of copper treatments in organic farming. Starting from meteo-climatic, agronomic and phytopathological data a partial least squares discriminant analysis was developed. Three different strategies were compared: treatments according to the established organic agricultural practice (standard); treatments according to the predictive model and untreated control where no fungicides against downy mildew were applied. The modelling approach was divided into three phases: 1) model calibration; 2) field testing and 3) a posteriori model performance evaluation. The prediction was separately considered and modelled for: i) disease onset and ii) disease progress. The results for phase 1 show a percentage of correct classification equal to 91.8 % for the disease onset with 3 days elapsed between the prediction of first potential attack and disease onset and to 91.23 % for disease progress. In field testing phase the percentage of correct classification was equal to about 81 % for both the analysed years (2009 and 2010). In the phase 3 the percentages were quietly higher for the 2009. The number of fungicide applications on the partial least squares discriminant analysis model was almost half compared with standard schedule both in 2009 and 2010. Finally this approach showed the possibility to reduce fungicidal treatments and to avoid applying copper not essential for disease control representing a first step in the model validation