527,625 research outputs found
Interactive Visualization of the Building of University of Economics â Varna via 3D Modeling
The object of this paper is presenting the University of Economics â Varna, using a 3D model with 3Ds MAX. Created in 1920, May 14, University of Economics - Varna is a cultural institution with a place and style of its own. With the emergence of the three-dimensional modeling we entered a new stage of the evolution of computer graphics. The main target is to preserve the historical vision, to demonstrate forward-thinking and using of future-oriented approaches
On the dynamical evolution of 2002 VE68
Minor planet 2002 VE68 was identified as a quasi-satellite of Venus shortly
after its discovery. At that time its data-arc span was only 24 days, now it is
2,947 days. Here we revisit the topic of the dynamical status of this
remarkable object as well as look into its dynamical past and explore its
future orbital evolution which is driven by close encounters with both the
Earth-Moon system and Mercury. In our calculations we use a Hermite integration
scheme, the most updated ephemerides and include the perturbations by the eight
major planets, the Moon and the three largest asteroids. We confirm that 2002
VE68 currently is a quasi-satellite of Venus and it has remained as such for at
least 7,000 yr after a close fly-by with the Earth. Prior to that encounter the
object may have already been co-orbital with Venus or moving in a classical,
non-resonant Near-Earth Object (NEO) orbit. The object drifted into the
quasi-satellite phase from an L4 Trojan state. We also confirm that, at
aphelion, dangerously close encounters with the Earth (under 0.002 AU, well
inside the Hill sphere) are possible. We find that 2002 VE68 will remain as a
quasi-satellite of Venus for about 500 yr more and its dynamical evolution is
controlled not only by the Earth, with a non-negligible contribution from the
Moon, but by Mercury as well. 2002 VE68 exhibits resonant (or near resonant)
behavior with Mercury, Venus and the Earth. Our calculations indicate that an
actual collision with the Earth during the next 10,000 yr is highly unlikely
but encounters as close as 0.04 AU occur with a periodicity of 8 years.Comment: 12 pages, 17 figures, accepted for publication in MNRAS (figures
scaled-down
The object of fashion : methodological approaches to the history of fashion
This essay considers the role of artefacts in the historical study of dress and fashion and suggests the existence of three different approaches. The field of history of dress and costume has a long tradition going back to the nineteenth century. It adopts the methodologies of art history and considers artefacts as central to the analysis of different periods and themes. In the last few decades the emergence of fashion studies has been interpreted as a distancing from artefacts. It is here claimed that fashion studies brought theoretical rigour and embraced a deductive methodology of analysis in which artefacts still played an important function. The final part of this essay introduces the reader to what I call the material culture of fashion, a hybrid methodology borrowed from anthropology and archeology in which the object is central in the study of social, cultural and economic practices that are time specific. It shows in particular the challenges and paybacks of such an approach
Exploring Maintainability Assurance Research for Service- and Microservice-Based Systems: Directions and Differences
To ensure sustainable software maintenance and evolution, a diverse set of activities and concepts like metrics, change impact analysis, or antipattern detection can be used. Special maintainability assurance techniques have been proposed for service- and microservice-based systems, but it is difficult to get a comprehensive overview of this publication landscape. We therefore conducted a systematic literature review (SLR) to collect and categorize maintainability assurance approaches for service-oriented architecture (SOA) and microservices. Our search strategy led to the selection of 223 primary studies from 2007 to 2018 which we categorized with a threefold taxonomy: a) architectural (SOA, microservices, both), b) methodical (method or contribution of the study), and c) thematic (maintainability assurance subfield). We discuss the distribution among these categories and present different research directions as well as exemplary studies per thematic category. The primary finding of our SLR is that, while very few approaches have been suggested for microservices so far (24 of 223, ?11%), we identified several thematic categories where existing SOA techniques could be adapted for the maintainability assurance of microservices
Pattern Reification as the Basis for Description-Driven Systems
One of the main factors driving object-oriented software development for
information systems is the requirement for systems to be tolerant to change. To
address this issue in designing systems, this paper proposes a pattern-based,
object-oriented, description-driven system (DDS) architecture as an extension
to the standard UML four-layer meta-model. A DDS architecture is proposed in
which aspects of both static and dynamic systems behavior can be captured via
descriptive models and meta-models. The proposed architecture embodies four
main elements - firstly, the adoption of a multi-layered meta-modeling
architecture and reflective meta-level architecture, secondly the
identification of four data modeling relationships that can be made explicit
such that they can be modified dynamically, thirdly the identification of five
design patterns which have emerged from practice and have proved essential in
providing reusable building blocks for data management, and fourthly the
encoding of the structural properties of the five design patterns by means of
one fundamental pattern, the Graph pattern. A practical example of this
philosophy, the CRISTAL project, is used to demonstrate the use of
description-driven data objects to handle system evolution.Comment: 20 pages, 10 figure
- âŠ