30,405 research outputs found
A thread-tag based semantics for sequence diagrams
The sequence diagram is one of the most popular behaviour modelling languages which offers an intuitive and visual way of describing expected behaviour of object-oriented software. Much research work has investigated ways of providing a formal semantics for sequence diagrams. However, these proposed semantics may not properly interpret sequence diagrams when lifelines do not correspond to threads of controls. In this paper, we address this problem and propose a thread-tag based sequence diagram as a solution. A formal, partially ordered multiset based semantics for the thread-tag based sequence diagrams is proposed
Correctness of an STM Haskell implementation
A concurrent implementation of software transactional memory in Concurrent Haskell using a call-by-need functional language with processes and futures is given. The description of the small-step operational semantics is precise and explicit, and employs an early abort of conflicting transactions. A proof of correctness of the implementation is given for a contextual semantics with may- and should-convergence. This implies that our implementation is a correct evaluator for an abstract specification equipped with a big-step semantics
Developing a Mathematical Model for Bobbin Lace
Bobbin lace is a fibre art form in which intricate and delicate patterns are
created by braiding together many threads. An overview of how bobbin lace is
made is presented and illustrated with a simple, traditional bookmark design.
Research on the topology of textiles and braid theory form a base for the
current work and is briefly summarized. We define a new mathematical model that
supports the enumeration and generation of bobbin lace patterns using an
intelligent combinatorial search. Results of this new approach are presented
and, by comparison to existing bobbin lace patterns, it is demonstrated that
this model reveals new patterns that have never been seen before. Finally, we
apply our new patterns to an original bookmark design and propose future areas
for exploration.Comment: 20 pages, 18 figures, intended audience includes Artists as well as
Computer Scientists and Mathematician
Combining SysML and AADL for the design, validation and implementation of critical systems
The realization of critical systems goes through multiple phases of specification, design, integration, validation, and testing. It starts from high-level sketches down to the final product. Model-Based Design has been acknowledged as a good conveyor to capture these steps. Yet, there is no universal solution to represent all activities. Two candidates are the OMG-based SysML to perform high-level modeling tasks, and the SAE AADL to perform lower-level ones, down to the implementation. The paper shares an experience on the seamless use of SysML and the AADL to model, validate/verify and implement a flight management system
Software Design Guidelines for Usability
For years, the Human Computer Interaction (HCI) community has crafted usability guidelines that clearly define what characteristics a software system should have in order to be easy to use. However, in the Software Engineering (SE) community keep falling short of successfully incorporating these recommendations into software projects. From a SE perspective, the process of incorporating usability features into software is not always straightforward, as a large number of these features have heavy implications in the underlying software architecture. For example, successfully including an “undo” feature in an application requires the design and implementation of many complex interrelated data structures and functionalities. Our work is focused upon providing developers with a set of software design patterns to assist them in the process of designing more usable software. This would contribute to the proper inclusion of specific usability features with high impact on the software design. Preliminary validation data show that usage of the guidelines also has positive effects on development time and overall software design quality
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