Data structures and software tools for the computer aided design of control systems: a survey.

CAD software can be structured as a set of modular 'software tools' only if there is some agreement on the data structures which are to be passed between tools. Beyond this basic requirement, it is desirable to give the agreed structures the status of 'data types' in the language used for interactive design. The ultimate refinement is to have a data management capability which 'understands' how to manipulate such data types. In this paper the requirements of CACSD are formulated from the point of view of Database Management Systems. Progress towards meeting these requirements in both the DBMS and the CACSD community is reviewed. The conclusion reached is that there has been considerable movement towards the realisation of software tools for CACSD, but that this owes more to modern ideas about programming languages, than to DBMS developments. The DBMS field has identified some useful concepts, but further significant progress is expected to come from the exploitation of concepts such as object-oriented programming, logic programming, or functional programming.

The use of object oriented modelling and simulation tools in constraint satisfaction for embodiment design

The software package Dymola, which implements the new, vendor-independent standard modelling language Modelica, exemplifies the emerging generation of object-oriented modelling and simulation tools. This paper shows how, in addition to its simulation capabilities, it may be used as an embodiment design tool, to size automatically a design assembled from a library of generic parametric components. The example used is a miniature model aircraft diesel engine. To this end, the component classes contain extra algebraic equations calculating the overload factor (or its reciprocal, the safety factor) for all the different modes of failure, such as buckling or tensile yield. Thus the simulation results contain the maximum overload or minimum safety factor for each failure mode along with the critical instant and the device state at which it occurs. The Dymola "Initial Conditions Calculation" function, controlled by a simple software script, may then be used to perform automatic component sizing. Each component is minimised in mass, subject to a chosen safety factor against failure, over a given operating cycle. Whilst the example is in the realm of mechanical design, it must be emphasised that the approach is equally applicable to the electrical or mechatronic domains, indeed to any design problem requiring numerical constraint satisfaction.

Traceability applications based on Discovery Services

RFID, in its different forms, but especially following EPCglobal standards, has become a key enabling technology for many applications. An essential component to develop track and trace applications in a complex multi-vendor scenario are the Discovery Services. Although they are already envisaged as part of the EPCglobal network architecture, the functional definition and standardization of the Discovery Service is still at a very early stage. Within the scope of the BRIDGE project, a specification for the interfaces of Discovery Services has been developed, together with a prototype to validate the design and different models to enhance supply-chain control through track and trace applications. © 2008 IEEE.

Security considerations in the design and peering of RFID discovery services

There is growing interest in Discovery Services for locating RFID and supply chain data between companies globally, to obtain product lifecycle information for individual objects. Discovery Services are heralded as a means to find serial-level data from previously unknown parties, however more realistically they provide a means to reduce the communications load on the information services, the network and the requesting client application. Attempts to design a standardised Discovery Service will not succeed unless security is considered in every aspect of the design. In this paper we clearly show that security cannot be bolted-on in the form of access control, although this is also required. The basic communication model of the Discovery Service critically affects who shares what data with whom, and what level of trust is required between the interacting parties. © 2009 IEEE.

Breathers and thermal relaxation as a temporal process: A possible way to detect breathers in experimental situations

Breather stability and longevity in thermally relaxing nonlinear arrays is investigated under the scrutiny of the analysis and tools employed for time series and state reconstruction of a dynamical system. We briefly review the methods used in the analysis and characterize a breather in terms of the results obtained with such methods. Our present work focuses on spontaneously appearing breathers in thermal Fermi-Pasta-Ulam arrays but we believe that the conclusions are general enough to describe many other related situations; the particular case described in detail is presented as another example of systems where three incommensurable frequencies dominate their chaotic dynamics (reminiscent of the Ruelle-Takens scenario for the appearance of chaotic behavior in nonlinear systems). This characterization may also be of great help for the discovery of breathers in experimental situations where the temporal evolution of a local variable (like the site energy) is the only available/measured data. © 2005 American Institute of Physics.

A method for identifying scope and assumptions in developing and selecting methods and tools

This technical report describes a practical method consisting of a checklist and a supporting techniques for those planning or just starting to develop or select design tools and methods. The method helps to summarize and illustrate the envisaged tool or method by identifying its scope and the underlying assumptions. The resulting tool or method description clarifies the problem that is addressed, the approach and the possible implications, and can thus be used by a variety of people involved in assessing a tool or method in an early stage. For the developers themselves the method reveals how realistic the envisaged method or tool is, and whether the scope has to be narrowed.