638,495 research outputs found
Identity-based tracking of products and product data in changing networks
The paper addresses a subject of high relevance for small and medium sized enterprises (SMEs) participating in today's changing supply chains. Product-centric application development and using design patterns to link related web-services directly to the electronic identity of products are proposed. To identify and track products the ID@URI identification scheme is advocated. The scheme combines serial numbers and URLs to produce globally unique product identifiers. The TraSer-project aiming at implementing an open-source solution platform for product centric web-services has been started this year. Based on the first phase of the project the paper also outlines differences and advantages of the TraSer-approach compared to other existing approaches
GlycoPep Grader: A web-based utility for assigning the composition of N-linked glycopeptides
GlycoPep Grader (GPG) is a freely-available software tool designed to accelerate the process of accurately determining glycopeptide composition from tandem mass spectrometric data. GPG relies on the identification of unique dissociation patterns shown for high mannose, hybrid, and complex N-linked glycoprotein types, including patterns specific to those structures containing fucose or sialic acid residues. The novel GPG scoring algorithm scores potential candidate compositions of the same nominal mass against MS/MS data through evaluation of the Y1 ion and other peptide-containing product ions, across multiple charge states, when applicable. In addition to evaluating the peptide portions of a given glycopeptide, the GPG algorithm predicts and scores product ions that result from unique neutral losses of terminal glycans. GPG has been applied to a variety of glycoproteins, including RNase B, asialofetuin and transferrin, and the HIV envelope glycoprotein, CON-S gp140 CFI. The GPG software is implemented predominantly in PostgreSQL, with PHP as the presentation tier, and is publically accessible online. Thus far, the algorithm has identified the correct compositional assignment from multiple candidate N-glycopeptides in all tests performed
The flexible coefficient multinomial logit (FC-MNL) model of demand for differentiated products
We show FC-MNL is flexible in the sense of Diewert (1974), thus its parameters can be chosen to match a well-defined class of possible own- and cross-price elasticities of demand. In contrast to models such as Probit and Random Coefficient-MNL models, FC-MNL does not require estimation via simulation; it is fully analytic. Under well-defined and testable parameter restrictions, FC-MNL is shown to be an unexplored member of McFaddenâs class of Multivariate Extreme Value discrete-choice models. Therefore, FC-MNL is fully consistent with an underlying structural model of heterogeneous, utility-maximizing consumers. We provide a Monte-Carlo study to establish its properties and we illustrate the use by estimating the demand for new automobiles in Italy
Improving institutional memory on challenges and methods for estimation of pig herd antimicrobial exposure based on data from the Danish Veterinary Medicines Statistics Program (VetStat)
With the increasing occurrence of antimicrobial resistance, more attention
has been directed towards surveillance of both human and veterinary
antimicrobial use. Since the early 2000s, several research papers on Danish pig
antimicrobial usage have been published, based on data from the Danish
Veterinary Medicines Statistics Program (VetStat). VetStat was established in
2000, as a national database containing detailed information on purchases of
veterinary medicine. This paper presents a critical set of challenges
originating from static system features, which researchers must address when
estimating antimicrobial exposure in Danish pig herds. Most challenges
presented are followed by at least one robust solution. A set of challenges
requiring awareness from the researcher, but for which no immediate solution
was available, were also presented. The selection of challenges and solutions
was based on a consensus by a cross-institutional group of researchers working
in projects using VetStat data. No quantitative data quality evaluations were
performed, as the frequency of errors and inconsistencies in a dataset will
vary, depending on the period covered in the data. Instead, this paper focuses
on clarifying how VetStat data may be translated to an estimation of the
antimicrobial exposure at herd level, by suggesting uniform methods of
extracting and editing data, in order to obtain reliable and comparable
estimates on pig antimicrobial consumption for research purposes.Comment: 25 pages, including two Appendices (pages not numbered). Title page,
including abstract, is on page 1. Body of text, including references,
abbreviation list and disclaimers for conflict of interest and funding, are
on pages 2-18. Two figures embedded in the text on pages 3 and 5. Appendix 1
starts on page 19, and Appendix 2 on page 2
Towards Automated Performance Bug Identification in Python
Context: Software performance is a critical non-functional requirement,
appearing in many fields such as mission critical applications, financial, and
real time systems. In this work we focused on early detection of performance
bugs; our software under study was a real time system used in the
advertisement/marketing domain.
Goal: Find a simple and easy to implement solution, predicting performance
bugs.
Method: We built several models using four machine learning methods, commonly
used for defect prediction: C4.5 Decision Trees, Na\"{\i}ve Bayes, Bayesian
Networks, and Logistic Regression.
Results: Our empirical results show that a C4.5 model, using lines of code
changed, file's age and size as explanatory variables, can be used to predict
performance bugs (recall=0.73, accuracy=0.85, and precision=0.96). We show that
reducing the number of changes delivered on a commit, can decrease the chance
of performance bug injection.
Conclusions: We believe that our approach can help practitioners to eliminate
performance bugs early in the development cycle. Our results are also of
interest to theoreticians, establishing a link between functional bugs and
(non-functional) performance bugs, and explicitly showing that attributes used
for prediction of functional bugs can be used for prediction of performance
bugs
An Analysis of Optical Contributions to a Photo-Sensor's Ballistic Fingerprints
Lens aberrations have previously been used to determine the provenance of an
image. However, this is not necessarily unique to an image sensor, as lens
systems are often interchanged. Photo-response non-uniformity noise was
proposed in 2005 by Luk\'a\v{s}, Goljan and Fridrich as a stochastic signal
which describes a sensor uniquely, akin to a "ballistic" fingerprint. This
method, however, did not account for additional sources of bias such as lens
artefacts and temperature.
In this paper, we propose a new additive signal model to account for
artefacts previously thought to have been isolated from the ballistic
fingerprint. Our proposed model separates sensor level artefacts from the lens
optical system and thus accounts for lens aberrations previously thought to be
filtered out. Specifically, we apply standard image processing theory, an
understanding of frequency properties relating to the physics of light and
temperature response of sensor dark current to classify artefacts. This model
enables us to isolate and account for bias from the lens optical system and
temperature within the current model.Comment: 16 pages, 9 figures, preprint for journal submission, paper is based
on a thesis chapte
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Digitizing mass spectrometry data to explore the chemical diversity and distribution of marine cyanobacteria and algae.
Natural product screening programs have uncovered molecules from diverse natural sources with various biological activities and unique structures. However, much is yet underexplored and additional information is hidden in these exceptional collections. We applied untargeted mass spectrometry approaches to capture the chemical space and dispersal patterns of metabolites from an in-house library of marine cyanobacterial and algal collections. Remarkably, 86% of the metabolomics signals detected were not found in other available datasets of similar nature, supporting the hypothesis that marine cyanobacteria and algae possess distinctive metabolomes. The data were plotted onto a world map representing eight major sampling sites, and revealed potential geographic locations with high chemical diversity. We demonstrate the use of these inventories as a tool to explore the diversity and distribution of natural products. Finally, we utilized this tool to guide the isolation of a new cyclic lipopeptide, yuvalamide A, from a marine cyanobacterium
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