81 research outputs found
On the Unification of Megamodels
Through the more and more widespread application of model-driven engineering (MDE) and the increasing diversity in applied modeling paradigms within single projects, there is an increasing need to capture not only models in isolation but also their relations.This paper is a survey on techniques capturing such relations, such as megamodels or macromodels, based on existing scientific literature. Therefore, we consider various definitions of these techniques. We further examine characteristics of the different techniques.We will propose a unified core definition of a megamodel that captures the core properties of megamodels and which can be extended to the needs of the different applications of megamodels.Finally, we give an outlook on arising application areas for megamodels
Improved Flexibility and Scalability by Interpreting Story Diagrams
In this paper, we present an interpreter for Story Diagrams working on Eclipse Modeling Framework (EMF) models. The interpreter provides a more flexible and, under certain circumstances, a more scalable solution than the compiled Java code generated from Story Diagrams by Fujaba. of Dynamic EMF even allows the evolution of meta models at runtime. Story Diagrams can now be modeled and executed within Eclipse. They can be modified and re-executed by the Story Diagram interpreter immediately without recompiling the source code and restarting the application. Our implementation also supports higher-order transformations by using Story Diagrams to modify other Story Diagrams. generation is not applicable, like running systems. While interpretation obviously results in performance drawbacks, we demonstrate that the Story Diagram interpreter is able to improve the performance in certain worst-case situations compared to the average generated code. This is achieved by a dynamic ordering of the matching process, which considers the actual number of elements in an association at runtime. Such a dynamic ordering can minimize the matching effort considerably. In contrast, Fujaba generated code uses a static matching strategy. Whereas the Fujaba Story Diagrams have potentially high performance fluctuations, the performance of the Story Diagram interpreter is steadier and more scalable compared to the generated Java code
Navigating Across Non-Navigable Ecore References via OCL
The Eclipse Modeling Framework (EMF) and its meta-meta model Ecore support uni-directional and bi-directional references. It is quite common that references are defined uni-directionally only because of saving storage space or separating meta models, which is problematic when implementing Object Constraint Language (OCL) constraints that require navigation against the direction of uni-directional references. This is essential for certain approaches, e.g., incremental evaluation of OCL constraints on models shown by Altenhofen et al. that is used in SAP's Modeling Infrastructure (MOIN). In this paper, we present an approach that overcomes the aforementioned issue by providing navigation across non-navigable Ecore references via OCL. We further discuss different alternative solutions and briefly describe the realization that was outcome of a project in cooperation with the SAP AG
Investigating the influence of long-axial versus short-axial field of view PET/CT on stage migration in lymphoma and non-small cell lung cancer.
OBJECTIVES
The objective of this study was to evaluate the influence of a long-axial field-of-view (LAFOV) on stage migration using a large single-centre retrospective cohort in lymphoma and non-small cell lung cancer (NSCLC).
METHODS
A retrospective study is performed for patients undergoing PET/computed tomography (CT) on either a short-axial field-of-view (SAFOV) or LAFOV PET/CT system for the staging of known or suspected NSCLC or for therapeutic response in lymphoma. The primary endpoint was the Deauville therapy response score for patients with lymphoma for the two systems. Secondary endpoints were the American Joint Committee on Cancer stage for NSCLC, the frequency of cN3 and cM1 findings, the probability for a positive nodal staging (cN1-3) for NSCLC and the diagnostic accuracy for nodal staging in NSCLC.
RESULTS
One thousand two hundred eighteen records were screened and 597 patients were included for analysis (N = 367 for lymphoma and N = 291 for NSCLC). For lymphoma, no significant differences were found in the proportion of patients with complete metabolic response versus non-complete metabolic response Deauville response scores (P = 0.66). For NSCLC no significant differences were observed between the two scanners for the frequency of cN3 and cM1 findings, for positive nodal staging, neither the sensitivity nor the specificity.
CONCLUSIONS
In this study use of a LAFOV system was neither associated with upstaging in lymphoma nor NSCLC compared to a digital SAFOV system. Diagnostic accuracy was comparable between the two systems in NSCLC despite shorter acquisition times for LAFOV
Population Pharmacokinetics of Liposomal Amphotericin B in Immunocompromised Children
BACKGROUND
Liposomal amphotericin B (LAmB) is widely used in the treatment of invasive fungal disease (IFD) in adults and children. There are relatively limited PK data to inform optimal dosing in children that achieves systemic drug exposures comparable to those of adults.
OBJECTIVES
To describe the pharmacokinetics of LAmB in children aged 1-17 years with suspected or documented IFD.
METHODS
Thirty-five children were treated with LAmB at dosages of 2.5-10 mg kg(-1) daily. Samples were taken at baseline and at 0.5-2.0 hourly intervals for twenty-four hours after receipt of the first dose (n=35 patients) and on the final day of therapy (n=25 patients). LAmB was measured using high performance liquid chromatography (HPLC). The relationship between drug exposure and development of toxicity was explored.
RESULTS
An evolution in PK was observed during the course of therapy resulting in a proportion of patients (n=13) having significantly higher maximum serum concentration (Cmax) and area under the concentration time curve (AUC0-24) later in the course of therapy, without evidence of drug accumulation (Cmin accumulation ratio, AR < 1.2). The fit of a 2-compartment model incorporating weight and an exponential decay function describing volume of distribution best described the data. There was a statistically significant relationship between mean AUC0-24 and probability of nephrotoxicity (OR 2.37; 95% CI 1.84-3.22, p=0.004).
CONCLUSIONS
LAmB exhibits nonlinear pharmacokinetics. A third of children appear to experience a time-dependent change in PK, which is not explained by weight, maturation or observed clinical factors
An 18-34-GHz dynamic frequency divider based on 0.2-μm AlGaAs/GaAs/AlGaAs quantum-well transistors
The design and performance of a dynamic frequency divider was presented. This digital IC demonstrates the ability of the authors' AlGaAs/GaAs/AlGaAs quantum-well FETs with gate lengths of 0.2 μm. Stable operation was achieved in the frequency range from 18 GHz up to 34 GHz with a power consumption of 250 mW. To the authors' knowledge, this is the best result ever reported for HEMT circuits, and is similar to the frequency limit achieved by use of AlGaAs/GaAs HBTs
Digital dynamic frequency dividers for broad band application up to 60 GHz
A broadband dynamic frequency divider based on pseudomorphic Al0.2Ga0.8As/In0.25Ga0.75As MODFETs and passive loads is presented. Stable operation from 28 GHz up to 51 GHz with a power consumption of 440 mW could be shown. SPICE network simulation predicts operation in the 35 GHz - 60 GHz range for a divider circuit using an advanced E/D AlGaAs/InGaAs MODFET process
The Ocean is Losing its Breath: Declining Oxygen in the Worlds Ocean and Coastal Waters
'The Ocean is Losing its Breath' presents a summary of scientific experiments, observations and numerical models addressing the following questions: How has the oxygen content in the open ocean and coastal waters changed over the past century and through geological time? What are the mechanisms behind this oxygen decline? How is ocean oxygen content predicted to change over the rest of the twenty-first century? What are the consequences of low and declining oxygen concentrations in the marine environment? This document was prepared by a group of concerned scientists from across the world, the IOC expert group, the Global Ocean Oxygen Network GO2 NE, established in 2016, which is committed to providing a global and multidisciplinary view on deoxygenation, with a focus on understanding its various aspects and impacts
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