Skip to content
Free planNo credit card requiredStart writing
AI for Research home
AI for Research home
Dashboard
Sign inGet started

Search 250 million research papers

Read the abstract, see who wrote it and who cites it, and get the citation in APA, MLA, Chicago or Harvard.

About 10,000 papers for “model composition”

Executable model composition

Carlos Rodríguez, Mario Sánchez, Jorge Villalobos · 2011

Modularizing concerns is a common strategy to lower application complexity: it results in modules that are easy to maintain, to adapt, and to replace. In some cases, these modules can also be expressed with very expressive concern-specific languages that manage high level concepts. On the other hand, modularization also requires tools and languages to describe the relations and interactions between concerns and to reconstruct the full application semantics. Ideally, these descriptions should be written using languages that work with the same concepts than the concern specific languages. Cumbia is a metamodel-based platform to build applications that support multiple concern specific languages. However, the composition and coordination mechanism between concerns depends on a too low level language called CCL: since it is built around very basic and generic coordination primitives, using the language requires a strong technical knowledge of the platform, and it is difficult to implement tools that offer meaningful validations on compositions. In this paper we propose a composition metamodel to characterize, at metamodel level, the composition and coordination of Cumbia models. By adopting this solution, the mentioned problems are solved, and domain experts can have a more active role in the creation of models for Cumbia-based applications.

Cited by 9

Model composition in model checking

Ingo Felscher, Wolfgang Thomas · RWTH Publications (RWTH Aachen) · 2014

Model-checking allows one to formally check properties of systems: these properties are modeled as logic formulas and the systems as structures like transition systems. These transition systems are often composed, i.e., they arise in form of products or sums. The composition technique allows us to deduce the truth of a formula in the composed system from "interface information": the truth of formulas for the component systems and information in which components which of these formulas hold. We are interested in identifying situations where the composition technique works in the context of model-checking (reachability properties, linear and branching time temporal logic) and, in these cases, how large the interface information can become. In the first main part of this thesis, we extend known results for synchronized products of transition systems by showing a composition theorem for finitely synchronized products and first-order logic (or modal logic) extended by regular reachability over a unary alphabet. We further show that the composition technique fails for two generalizations of the logic: in the general case of regular reachability and in the case of propositional dynamic logic over a unary alphabet. Furthermore, it fails for synchronized products which are not finitely synchronized. A known drawback of the composition technique is the growth of the size of the generated interface information in relation to the given formula. Göller, Jung and Lohrey have shown a non-elementary lower bound for this size in general for first-order logic (for products) and modal logic (for disjoint ordered sums). In the second and third part of this thesis, we look at combinations of logics and systems where we can avoid this. In the second part, we show a composition theorem for linear temporal logic (LTL) and disjoint ordered sums of words. A careful analysis shows that, here, the size of the interface information only grows at most exponential in the size of the given formula. In the third part, we generalize this composition technique to a disjoint ordered sum of trees and computation tree logic (CTL). Here, we deal with trees as components which are composed via a tree structure. We show a composition result for which the interface information grows exponentially in the size of the given formula and in the branching of the index tree structure.

Cited by 0Open access

Modelling: Model Composition KUN

Frits Va · 2004

In the development of timed automata technology over the last decade, emphasis has been placed mostly on the verification engine. Even though significant progress has been made in the contect of Ametist, the input language of tools such as Uppaal is still (relatively) restricted and supports

Cited by 0

Semantics Preserving Model Composition.

Jon Oldevik · 2007

Separation of concerns (SoC) and modularisation are well established strategies for managing complex specifications [1, 2]. However, although software is designed with SoC in mind, the language mechanisms at hand often lead to tangling and scattering of concerns. This has motivated a range of language extensions to support concern specification, such as aspects and subjects in programming and modelling. The current trend is modularisation of cross-cutting concerns into units, e.g. aspects, that can later be composed by some transformation process (composition/merging/weaving). An important issue in this process is how the semantics of the models/programs is preserved. The focus of this PhD work is on composition and configuration of software specifications from a modelling perspective. Standard mechanisms in modelling (e.g. in UML) provide composition and configuration with well understood characteristics. Examples from UML are class redefinitions, composite structures, composite states, structured activities, interaction decomposition, and package merge. This work goes beyond those by exploring modelling and composition of concerns at a collaboration level, focusing on their architecture and interaction dimensions. The semantics governing such compositions and their results is of particular interest in this regard. I will address how generative techniques can be used for implementing the compositions and guide semantics preservation. I will also address what semantics preservation means in different modelling and composition contexts. UML is used as the language for experimentation, as this is the de-facto standard for software modelling.

Cited by 0

Minimal-cut model composition

Tal Hassner, Lihi Zelnik‐Manor, George Leifman et al. · 2006

Constructing new, complex models is often done by reusing parts of existing models, typically by applying a sequence of segmentation, alignment and composition operations. Segmentation, either manual or automatic, is rarely adequate for this task, since it is applied to each model independently, leaving it to the user to trim the models and determine where to connect them. In this paper we propose a new composition tool. Our tool obtains as input two models, aligned either manually or automatically, and a small set of constraints indicating which portions of the two models should be preserved in the final output. It then automatically negotiates the best location to connect the models, trimming and stitching them as required to produce a seamless result. We offer a method based on the graph theoretic minimal cut as a means of implementing this new tool. We describe a system intended for both expert and novice users, allowing easy and flexible control over the composition result. In addition, we show our method to be well suited for a variety of model processing applications such as model repair, hole filling, and piecewise rigid deformations.

Cited by 14

Minimal-Cut Model Composition

T. Hassner, L. Zelnik-Manor, G. Leifman, R. Basri · 2005

Constructing new, complex models is often done by reusing parts of existing models, typically by applying a sequence of segmentation, alignment and composition operations. Segmentation, either manual or automatic, is rarely adequate for this task, since it is applied to each model independently, leaving it to the user to trim the models and determine where to connect them. In this paper we propose a new composition tool. Our tool obtains as input two models, aligned either manually or automatically, and a small set of constraints indicating which portions of the two models should be preserved in the final output. It then automatically negotiates the best location to connect the models, trimming and stitching them as required to produce a seamless result. We offer a method based on the graph theoretic minimal cut as a means of implementing this new tool. We describe a system intended for both expert and novice users, allowing easy and flexible control over the composition result. In addition, we show our method to be well suited for a variety of model processing applications such as model repair, hole filling, and piecewise rigid deformations.

Cited by 0

Model composition and sensitivity analyses.

Susan R. Sama (14345174), Rebecca Gore (9438392), Ann Z. Bauer (16378713) et al. · Figshare · 2023

<div><p>Introduction</p><p>The demographics of those developing severe coronavirus disease (COVID-19) outcomes are shifting to younger patients. In an observational study utilizing electronic health records from a Massachusetts group medical practice, we identified 5025 patients with confirmed COVID-19 from March 1 to December 18, 2020. Of these, 3870 were under 65 years of age. We investigated the hypothesis that pre-infection metabolic or immunologic dysregulation including polycystic ovary syndrome (PCOS) increased risk of serious COVID-19 outcomes in patients under 65 years of age.</p><p>Materials and methods</p><p>We compared those with COVID-19 related hospitalization or mortality to all other COVID-19 patients, using a case control approach. Using logistic regression and propensity score modeling, we evaluated risk of developing severe COVID-19 outcomes (hospitalization or death) in those with <i>pre-infection</i> comorbidities, metabolic risk factors, or PCOS.</p><p>Results</p><p>Overall, propensity score matched analyses demonstrated <i>pre-infection</i> elevated liver enzymes alanine aminotransferase (ALT) >40, aspartate aminotransferase (AST) >40 and blood glucose ≥215 mg/dL were associated with more severe COVID-19 outcomes, OR = 1.74 (95% CI 1.31, 2.31); OR = 1.98 (95% CI 1.52, 2.57), and OR = 1.55 (95% CI 1.08, 2.23) respectively. Elevated hemoglobin A1C or blood glucose levels were even stronger risk factors for severe COVID-19 outcomes among those aged < 65, OR = 2.31 (95% CI 1.14, 4.66) and OR = 2.42 (95% CI 1.29, 4.56), respectively. In logistic regression models, women aged < 65 with PCOS demonstrated more than a four-fold increased risk of severe COVID-19, OR 4.64 (95% CI 1.98, 10.88).</p><p>Conclusion</p><p>Increased risk of severe COVID-19 outcomes in those < age 65 with <i>pre-infection</i> indicators of metabolic dysfunction heightens the importance of monitoring pre-infection indicators in younger patients for prevention and early treatment. The PCOS finding deserves further investigation. Meanwhile women who suffer from PCOS should be carefully evaluated and prioritized for earlier COVID-19 treatment and vaccination.</p></div>

Cited by 0Open access

Simulation Model Composition using BOMs

Farshad Moradi, Peder Nordvaller, Rassul Ayani · 2006

Development of simulation models is a multi-disciplinary and time/resource consuming process. An approach to reduce the associated costs and improving the usability of the models is to compose simulation models through reuse of predefined and already existing, validated simulation components. Using this method the simulation model is built in a component-based fashion. The Base Object Model, BOM, is a new standard for defining reusable and composable simulation components. The introduction of BOMs into the simulation community opens up the possibility of component based simulation development approach that is faster and more efficient than today's simulation creation process. In this paper we describe a process that has been developed at the Swedish Defence Research Agency (FOI) with the aim to speed up and improve the development of simulation models. This process utilizes the BOM concept coupled with ontologies in simulation development, and employs SRML (Simulation Reference Markup Language) as a means to define a component based simulation on a high-level. We present our experimental results and findings based on our implementation of the proposed process. Our experience indicates that including ontological information in BOMs will further increase their usability

Cited by 26

A New Model of Composition

Verity Harte · 2002

Abstract This chapter, along with the next, focuses on the alternative model of composition that Plato develops to respond to the problems he has posed in his discussion of the rejected model. The focus here is first on the Parmenides, from which the outline of an alternative theory emerges, and then on the Theaetetus and the Sophist, from which some of the broader context of Plato's problem of composition is recovered within which his solution to the problem takes shape. Central to this solution is Plato's distinguishing of the part–whole relation from the relations of distinctness and, more importantly, of identity. On the alternative model, composition is restricted; it is ontologically committed or creative; and it centrally involves the existence of certain structural relations between the parts of a whole.

Cited by 0

Model composition and sequence information.

Kai Ehrenbolger (9585516), Nathan Jespersen (9585519), Himanshu Sharma (141539) et al. · Figshare · 2020

<p>Bolded and underlined sequences were modeled with side-chains while green regions were trimmed but still contain side-chain information. Sections indicated in yellow were modeled with poly-alanine structural elements, and the ubiquitin moiety of eL40 is indicated in blue.</p> <p>(PDF)</p>

Cited by 0Open access

Measuring Unemployment: A Composition Model

Fraser Jackson · Labour Employment and Work in New Zealand · 2015

In looking at statistics of the labour market, the labour force status categories are often considered as independent, but when expressed as proportions they are observations over a simplex of non-negative components summing to 1. This leads to serious deficiencies in the conventional tools of analysis, and a framework commonly referred to as compositional modelling has been developed to address them. This paper explores the application of these tools to labour force data and demonstrates simple consistent patterns between job search (unemployment) and current participation levels across both aggregate and age and gender sub populations. Unlike previous uses of composition models in labour market studies we use a simple transform with a direct interpretation for our analysis.

Cited by 0Open access