Steane-Enlargement of Quantum Codes from the Hermitian Curve

In this paper, we study the construction of quantum codes by applying Steane-enlargement to codes from the Hermitian curve. We cover Steane-enlargement of both usual one-point Hermitian codes and of order bound improved Hermitian codes. In particular, the paper contains two constructions of quantum codes whose parameters are described by explicit formulae, and we show that these codes compare favourably to existing, comparable constructions in the literature.Comment: 11 page

On Steane-Enlargement of Quantum Codes from Cartesian Product Point Sets

In this work, we study quantum error-correcting codes obtained by using Steane-enlargement. We apply this technique to certain codes defined from Cartesian products previously considered by Galindo et al. in [4]. We give bounds on the dimension increase obtained via enlargement, and additionally give an algorithm to compute the true increase. A number of examples of codes are provided, and their parameters are compared to relevant codes in the literature, which shows that the parameters of the enlarged codes are advantageous. Furthermore, comparison with the Gilbert-Varshamov bound for stabilizer quantum codes shows that several of the enlarged codes match or exceed the parameters promised by the bound.Comment: 12 page

Creating Conditions for Participation: Conflicts and Resources in Systems Design

User participation in design is a well recognized way of gaining more knowledge about work, and of improving the quality of the computer application to be designed. Yet many experiences with user participation were gained under circumstances quite different from those of corporations in the 1990's - in the Scandinavian collective resource projects. This paper will argue that a lot can still be learned from these projects, in particular when it comes to the creation of conditions for participation.The paper will present a recent project, the AT project, in order to discuss the concerns and conditions of participatory design projects today. This discussion seeks inspiration also in philosophical concerns regarding human development. The main message is that we shouldn't throw out the baby with the bath water, though certainly many aspects need to be rethought. The paper goes on to suggest that new alliances between groups in organizations, with due concern for their diversity of resources, and with constructive use of the conflicts inherent in the organization despite their fundamentally conflicting interests, may be a way forward in empowering organizations, making room for groups and individuals within them to act. The paper discusses experiences with ways of setting up design activities in such an environment

Re-framing Research in Human-Computer Interaction from the Point-of-View of Activity Theory?

Within human-computer interaction cognitive science is today the leading approach. Yet its position is threaded philosophically as well as from within the field. Most attempts to re-frame human-computer interaction from within the field are minor revisions to the traditional theoretical basis, still without much to say about real-life computer applications. In this paper I shall present and discuss an alternative approach based on activity theory.The following summarizes the theoretical anchor points:Activity is mediated. That artifacts mediate use means that we are normally not aware of them as such in use, they are transparent to us. Artifacts are seen as historical devices.Although collective, each activity is conducted through actions of individuals.Activities are not taking place in isolation but interwoven with other activities. Artifacts may be the instruments of a web of activities. The concepts of breakdowns and focus shifts are used in the further analysis of specific computer applications in use, and a mapping technique for such analysis is developed. Based on an example I take the first steps towards a more contex\-tualized analysis of human-computer interaction. The human activity framework has provided a vehicle for bringing together an overall analysis of work and use of computer technology with a detailed analysis of human-computer interaction. It provides a way of understanding the relations between the overall socio-political conditions of work and the specific use of the specific computer application in a specific situation. What actually goes on may be analysed from many different levels of activity, where the actual actors are different, and maybe even different from those who conduct the specific actions

Mediating Technical Platforms to Support the Development of Shared Work Practices

This paper discusses two examples of how shared technical support platforms are adapted and developed in organizations. One is support for object oriented design and programming, the other, production of documents in an office. These two cases represent longitudinal studies of the use, the adaptation and the development of these platforms. This development involved active mediation of platform coordinators who were users of the shared environment, at the same time as they possessed, and developed further, skills and procedures to undertake its continued development. The paper applies a developmental perspective in that its concern is how the technical platform and the work practices surrounding it, are developing over time, and how the technical and organizational conditions have been in support of or a hindrance to this development