8,393 research outputs found
Executable assertions and flight software
Executable assertions are used to test flight control software. The techniques used for testing flight software; however, are different from the techniques used to test other kinds of software. This is because of the redundant nature of flight software. An experimental setup for testing flight software using executable assertions is described. Techniques for writing and using executable assertions to test flight software are presented. The error detection capability of assertions is studied and many examples of assertions are given. The issues of placement and complexity of assertions and the language features to support efficient use of assertions are discussed
Evolution of Ada technology in the flight dynamics area: Implementation/testing phase analysis
An analysis is presented of the software engineering issues related to the use of Ada for the implementation and system testing phases of four Ada projects developed in the flight dynamics area. These projects reflect an evolving understanding of more effective use of Ada features. In addition, the testing methodology used on these projects has changed substantially from that used on previous FORTRAN projects
Efficient and Playful Tools to Teach Unix to New Students
Teaching Unix to new students is a common tasks in many higher schools. This
paper presents an approach to such course where the students progress
autonomously with the help of the teacher. The traditional textbook is
complemented with a wiki, and the main thread of the course is a game, in the
form of a treasure hunt. The course finishes with a lab exam, where students
have to perform practical manipulations similar to the ones performed during
the treasure hunt. The exam is graded fully automatically. This paper discusses
the motivations and advantages of the approach, and gives an overall view of
the tools we developed. The tools are available from the web, and open-source,
hence re-usable outside the Ensimag.Comment: ITiCSE, Darmstadt : Germany (2011
Boundary Condition Adjustment Methods And Systems
Methods and systems for reactor lattice depletion are disclosed. One exemplary method, among others, comprises the steps of defining a reactor eigenvalue, the reactor eigenvalue being a specified ratio of actual neutron production to loss in the reactor; producing a lattice eigenvalue, the lattice eigenvalue being an estimated ratio of neutron production to loss in the lattice; and adjusting a boundary condition of the lattice to cause convergence of the lattice eigenvalue and the reactor eigenvalue in order to produce at least one physics parameter.Georgia Tech Research Corporatio
Expanding atmosphere models for SSS spectra of novae
Super Soft Source (SSS) spectra are powered by nuclear burning on the surface
of a white dwarf. The released energy causes a radiatively-driven wind that
leads to a radially extended atmosphere around the white dwarf. Significant
blue shifts in photospheric absorption lines are found in the spectra of novae
during their SSS phase, being an evidence of continued mass loss in this phase.
We present spherically symmetric PHOENIX models that account for the expansion
of the ejecta. A comparison to a plane parallel, hydrostatic atmosphere model
demonstrates that the mass loss can have a significant impact on the model
spectra. The dynamic model yields less pronounced absorption edges, and harder
X-ray spectra are the result. Therefore, lower effective temperatures are
needed to explain the observed spectra. Although both types of models are yet
to be fine-tuned in order to accurately determine best fit parameters, the
implications on the chemical abundances are going in opposite directions. With
the expanding models the requirement for strong depletion of the crucial
elements that cause these edges is now avoidable.Comment: 4 pages, accepted for A
A gentle transition from Java programming to Web Services using XML-RPC
Exposing students to leading edge vocational areas of relevance such as Web Services can be difficult. We show a lightweight approach by embedding a key component of Web Services within a Level 3 BSc module in Distributed Computing. We present a ready to use collection of lecture slides and student activities based on XML-RPC. In
addition we show that this material addresses the central topics in the context of web services as identified by Draganova (2003)
A conceptual model for megaprogramming
Megaprogramming is component-based software engineering and life-cycle management. Magaprogramming and its relationship to other research initiatives (common prototyping system/common prototyping language, domain specific software architectures, and software understanding) are analyzed. The desirable attributes of megaprogramming software components are identified and a software development model and resulting prototype megaprogramming system (library interconnection language extended by annotated Ada) are described
The C++0x "Concepts" Effort
C++0x is the working title for the revision of the ISO standard of the C++
programming language that was originally planned for release in 2009 but that
was delayed to 2011. The largest language extension in C++0x was "concepts",
that is, a collection of features for constraining template parameters. In
September of 2008, the C++ standards committee voted the concepts extension
into C++0x, but then in July of 2009, the committee voted the concepts
extension back out of C++0x.
This article is my account of the technical challenges and debates within the
"concepts" effort in the years 2003 to 2009. To provide some background, the
article also describes the design space for constrained parametric
polymorphism, or what is colloquially know as constrained generics. While this
article is meant to be generally accessible, the writing is aimed toward
readers with background in functional programming and programming language
theory. This article grew out of a lecture at the Spring School on Generic and
Indexed Programming at the University of Oxford, March 2010
A practical approach to object based requirements analysis
Presented here is an approach developed at the Unisys Houston Operation Division, which supports the early identification of objects. This domain oriented analysis and development concept is based on entity relationship modeling and object data flow diagrams. These modeling techniques, based on the GOOD methodology developed at the Goddard Space Flight Center, support the translation of requirements into objects which represent the real-world problem domain. The goal is to establish a solid foundation of understanding before design begins, thereby giving greater assurance that the system will do what is desired by the customer. The transition from requirements to object oriented design is also promoted by having requirements described in terms of objects. Presented is a five step process by which objects are identified from the requirements to create a problem definition model. This process involves establishing a base line requirements list from which an object data flow diagram can be created. Entity-relationship modeling is used to facilitate the identification of objects from the requirements. An example is given of how semantic modeling may be used to improve the entity-relationship model and a brief discussion on how this approach might be used in a large scale development effort
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