Evolution of product line architectures

Product-line architectures, i.e. a software architecture and component set shared by a family of products, represents a promising approach to achieving reuse of software. Several companies are initiating or have recently adopted a product-line architecture. However, little experience is available with respect to the evolution of the products, the software components and the software architecture. Due to the higher level of interdependency between the various software assets, software evolution is a more complex process. We identified characterization of software product lines based on dimensions of primary assets, views on the organization and on assets life cycle stages and after that introduced categorizations of the evolution of the requirements, the software architecture and the software components. Our work is focused on analyzing different ways of managing modifications during architecture evolution.Eje: Bases de datosRed de Universidades con Carreras en Informática (RedUNCI

Development tools for mobile devices in market price information systems

There are already several applications on mobile devices that can be useful in agriculture. For example: GPS-enabled map software, individual cattle identification and tracking software and even complex agricultural systems. These are just beginning to spread in the Hungarian agrifood sector. The possibility of using for agribusiness of mobile internet and mobile tools is increasing. Mobile tools are really suitable for tasks like inspecting the evolution of prices of agricultural products. One of our application development is a mobile extension to access the Market Price Information System run by the Hungarian Agricultural Economics Research Institute. The accessibility of information demanded by market actors can be ensured effectively by using mobile tools. The biggest limitation for PDA is screen size. If it is getting smaller from full screen to PDA-sized and yet further to mobile phone dimensions, user performance drops. The main reason for this is that smaller screens make it more difficult for a user to make good judgements about the usefulness of any particular information. The development methods and tools help us to solve one part of these problems

SDN Access Control for the Masses

The evolution of Software-Defined Networking (SDN) has so far been predominantly geared towards defining and refining the abstractions on the forwarding and control planes. However, despite a maturing south-bound interface and a range of proposed network operating systems, the network management application layer is yet to be specified and standardized. It has currently poorly defined access control mechanisms that could be exposed to network applications. Available mechanisms allow only rudimentary control and lack procedures to partition resource access across multiple dimensions. We address this by extending the SDN north-bound interface to provide control over shared resources to key stakeholders of network infrastructure: network providers, operators and application developers. We introduce a taxonomy of SDN access models, describe a comprehensive design for SDN access control and implement the proposed solution as an extension of the ONOS network controller intent framework

Stellar Collisions and the Interior Structure of Blue Stragglers

Collisions of main sequence stars occur frequently in dense star clusters. In open and globular clusters, these collisions produce merger remnants that may be observed as blue stragglers. Detailed theoretical models of this process require lengthy hydrodynamic computations in three dimensions. However, a less computationally expensive approach, which we present here, is to approximate the merger process (including shock heating, hydrodynamic mixing, mass ejection, and angular momentum transfer) with simple algorithms based on conservation laws and a basic qualitative understanding of the hydrodynamics. These algorithms have been fine tuned through comparisons with the results of our previous hydrodynamic simulations. We find that the thermodynamic and chemical composition profiles of our simple models agree very well with those from recent SPH (smoothed particle hydrodynamics) calculations of stellar collisions, and the subsequent stellar evolution of our simple models also matches closely that of the more accurate hydrodynamic models. Our algorithms have been implemented in an easy to use software package, which we are making publicly available (see http://vassun.vassar.edu/~lombardi/mmas/). This software could be used in combination with realistic dynamical simulations of star clusters that must take into account stellar collisions.Comment: This revised version has 37 pages, 13 figures, 4 tables; submitted to ApJ; for associated software package, see http://vassun.vassar.edu/~lombardi/mmas/ This revised version presents additional comparisons with SPH results and slightly improved merger recipe

A model comparison to predict heat transfer during spot GTA welding

The present work deals with the estimation of the time evolution of the weld fusion boundary. This moving boundary is the result of a spot GTA welding process on a 316L stainless steel disk. The estimation is based on the iterative regularization method. Indeed, the three problems: direct, in variation and adjoint, classically associated with this method, are solved by the finite element method in a two-dimensional axisymmetric domain. The originality of this work is to treat an experimental estimation of a front motion using a model with a geometry including only the solid phase. In this model, the evolution of this solid domain during the fusion is set with the ALE moving mesh method (Arbitrary Lagrangian Eulerian). The numerical developments are realized with the commercial code Comsol Multiphysics® coupled with the software Matlab®. The estimation method has been validated in a previous work using theoretical data ([1]). The experimental data, used here for this identification are, temperatures measured by thermocouples in the solid phase, the temporal evolution of the melt pool boundary observed at the surface by a fast camera and the maximal dimensions of the melted zone measured on macrographs. These experimental data are also compared with numerical results obtained from a heat and fluid flow model taking into account surface tension effects, Lorentz forces and the deformation of the melt pool surface under arc pressure

Symbolic computation of conservation laws for nonlinear partial differential equations in multiple space dimensions

A method for symbolically computing conservation laws of nonlinear partial differential equations (PDEs) in multiple space dimensions is presented in the language of variational calculus and linear algebra. The steps of the method are illustrated using the Zakharov-Kuznetsov and Kadomtsev-Petviashvili equations as examples. The method is algorithmic and has been implemented in Mathematica. The software package, ConservationLawsMD.m, can be used to symbolically compute and test conservation laws for polynomial PDEs that can be written as nonlinear evolution equations. The code ConservationLawsMD.m has been applied to (2+1)-dimensional versions of the Sawada-Kotera, Camassa-Holm, and Gardner equations, and the multi-dimensional Khokhlov-Zabolotskaya equation.Comment: 26 pages. Paper will appear in Journal of Symbolic Computation (2011). Presented at the Special Session on Geometric Flows, Moving Frames and Integrable Systems, 2010 Spring Central Sectional Meeting of the American Mathematical Society, Macalester College, St. Paul, Minnesota, April 10, 201

Between the Lines: documenting the multiple dimensions of computer supported collaborations

When we consider the possibilities for the design and evaluation of Computer Supported Collaborative Learning (CSCL) we probably constrain the CS in CSCL to situations in which learners, or groups of learners collaborate with each other around a single computer, across a local intranet or via the global internet. We probably also consider situations in which the computer itself acts as a collaborative partner giving hints and tips either with or without the addition of an animated pedagogical agent. However, there are now many possibilities for CSCL applications to be offered to learners through computing technology that is something other than a desktop computer, such as the TV or a digital toy. In order to understand how such complex and novel interactions work, we need tools to map out the multiple dimensions of collaboration using a whole variety of technologies. This paper discusses the evolution of a documentation technique for collaborative interactions from its roots in a situation where a single learner is collaborating with a software learning partner, through its second generation: group use of multimedia, to its current test-bed: young children using digital toys and associated software. We will explore some of the challenges these different learning situations pose for those involved in the evaluation of collaborative learning