Software development process | EPFL Graph Search

In software engineering, a software development process is a process of planning and managing software development. It typically involves dividing software development work into smaller, parallel, or sequential steps or sub-processes to improve design and/or product management. It is also known as a software development life cycle (SDLC). The methodology may include the pre-definition of specific deliverables and artifacts that are created and completed by a project team to develop or maintain an application. Most modern development processes can be vaguely described as agile. Other methodologies include waterfall, prototyping, iterative and incremental development, spiral development, rapid application development, and extreme programming. A life-cycle "model" is sometimes considered a more general term for a category of methodologies and a software development "process" is a more specific term to refer to a specific process chosen by a specific organization. F

Extension of the nodal code DYN3D to SFR applications

Evgeny Nikitin

DYN3D is a well-established Light Water Reactor (LWR) simulation tool and is being extended for safety analyses of Sodium cooled Fast Reactors (SFRs) at the Helmholtz-Zentrum Dresden-Rossendorf. This thesis focuses on the first stage of the development process, that is, the extension and application of DYN3D for steady-state and transient SFR calculations on reactor core level. In contrast to LWRs, the SFR behavior is especially sensitive to thermal expansions of the reactor components. Therefore, a new thermal-mechanical module accounting for thermal expansions is implemented into DYN3D. At first step, this module is capable of treating two important thermal expansion effects occurring within the core, namely axial expansion of fuel rods and radial expansion of diagrid. In order to perform nodal calculations with DYN3D, pre-generated homogenized few-group cross sections (XS) are necessarily needed. Therefore, prior to the development of thermal expansion models, a general methodology for XS generation is established for SFR nodal calculations based on the use of the Monte Carlo code Serpent. The new methodological developments presented in this thesis are verified against the Monte Carlo solutions of Serpent. Two SFR cores are used for testing: the large oxide core of the OECD/NEA benchmark and a smaller core from the Phenix end-of-life tests. Finally, the extended DYN3D is validated against selected IAEA benchmark tests on the Phenix end-of-life experiments that contain both steady-state and transient calculations. The contribution to the SFR-related developments at the HZDR, as presented in this thesis, makes it possible of performing steady-state and transient calculations for SFRs on reactor core level by using DYN3D. With this study, the basis of the next stage of DYN3D developments is established, that is, the up-scale of SFR analysis to system level can continue by coupling with a sodium capable thermal-hydraulic system code.

EPFL2019

Limits of Seamlessness in Object-Oriented Software Development

Seamlessness is a promise often used to promote object orientation, and the use of object orientation in the different domains and in the different stages of the software development process has brought great improvements in seamlessness. Where can we find seamlessness? And are there different kinds of seamlessness? In this paper we look at seamlessness starting with the different models found in large software developments. To give a common base for the discussion a model architecture is presented and different aspects of seamlessness are defined. We then show on a general level, where object orientation has already brought some seamlessness, where it will hopefully bring a higher degree of seamlessness in the future and where it cannot bring seamlessness due to restrictions inherent to the model architecture. The emphasis of the discussion is not to present a complete theoretical treatment but rather to help software developers to judge the many claims about seamlessness.

1994

Extension of the nodal code DYN3D to SFR applications

Evgeny Nikitin

EPFL2019