Smart system adaptability

Introduction

A general aim for high-tech system development is to improve system evolvability, i.e. the ability to easily adapt systems in response to evolution of technology, competition, and/or customer expectations. Systems should be easily modifiable to take advance of new hardware and software technologies and to respond quickly to changing customer expectations. Current development approaches specify the functionality of a system at design-time. Such approaches are not sufficiently adequate to develop systems that easily adapt to environmental or product usage fluctuations. A viable answer to these new challenges is genuine system adaptability; i.e. the ability of the system to adapt itself to fluctuations in the environment, the use of the product, etc.; naturally, these adaptations should not require an expensive and time-consuming product development cycle.

The Océ digital document printers as industrial reference case

The digital document printers from Océ belong to today’s complex machines and products. They are characterized by the following:

• The system is configured around a physical process.
• The system involves both soft real-time and hard real-time computation.
• The product has a long life time in the field, requiring a continuous flow of options for product extensions.
• The system has high productivity requirements combining throughput, reliability, availability, coupled to a low mean-time between failure and low downtime.
• Developing the system technology base is a long-lasting and severe investment. Changes in this technology base form a major interrupt in development and result in new generations of the product in the field.
• The life-cycle cost of either the system or the product generated by the system, are under severe pressure.
• The system requires a run-time configuration towards multiple users (e.g. configure the system towards specific user profiles).

For Océ, market reputation is typically based on productivity (effective number of pages per minute), reliability (always operational), quality consistency (constant high quality and color consistency), ease-of-use, and a highly competitive cost of ownership for their customers.

Many market trends influence the architecture and design of a digital printer: design time changes occur due to shifting market requirements. Gradually, changeability is also required during run-time, e.g. to cope with changes in the environment that influence printing quality and consistency or to cope with other new media.

Research challenge and approach

The challenges of creating adaptable systems are manifold:

• Develop appropriate approaches to model and analyze the adaptable properties of the system in its environment.
• What system quantities to use and how to measure them during operation?
• What are the guidelines, approaches, and constructs to develop adaptable software and hardware?
• The definition of an adaptability strategy, based on measurements, adaptability possibilities, product environment, etc.
• The design of the control of both software and hardware to adapt the system’s behavior according to the defined strategy.
• The system adaptation can lead to emergent inappropriate and unpredictable behavior. How to guarantee correct run-time system behavior?

The research thus has strong multi-disciplinary aspects, requiring expertise in different technical and scientific domains, including system measurements and model-based interpretation of measurement data, system and software architecture adaptability, adaptable resource usage and control strategies. To be successful, it is necessary to establish meaningful combinations of the analytic, modeling, and implementation techniques of the various disciplines.

The research activities will initially be guided by three lines of attention and tightly coupled to the Océ digital printers.

Data path design (i.e., the digital stages from network to print head with several types of image processing), covering:

• Trade-off analysis of different design alternatives on basis of appropriate modeling methods;
• Support of design decisions at an early stage of a development project;
• Investigation which modeling methods to use;
• Investigation of how to get usable results out of the models;
• Ensure usability of the approach in an industrial context by applying results in an industrial setting and within industrial constraints.

Adaptive control of physical layer (i.e., the control of the printing device itself), covering

• Adaptability in the physical layer of the system within a real-time constrained environment with much uncertainty from own devices, environment, print media, and user;
• Trade-off between model-based (white or grey box) and measurement-based (black-box, reinforcement learning) approaches; Decision at which level (physical, hardware, software) adaptability tasks have to be solved most efficiently and effectively;
• Development and prototyping of algorithms for adaptive control;
• Design of observers.

System level reasoning and design (i.e., the overall architecture of the adaptable system), covering

• Model-based interpretation of sensor data, taking into account changes to working conditions. A mixture of model-based diagnosis, probabilistic graphical models and decision theory will be applied;
• Definition of system-wide adaptability strategies for both the system life cycle (design time) and at system run-time;
• Definition of action plans for run-time adaptability;
• Dynamic software reconfiguration and parametrization;
• Software design for adaptability, including static and dynamic software verification to guarantee system integrity.

Partners and project organization

Octopus is a joint project of a consortium of industrial and academic partners. The Embedded Systems Institute (ESI) has the responsibility for project management and knowledge dissemination. Also, ESI Research Fellows coach and supplement the research activities of the academic partners.

Océ-Technologies B.V., the carrying industrial partner, provides the industrial challenge, expert knowledge in the domain of digital document printing systems (DDS), and specialized facilities, e.g. for experiments and prototyping. Océ provides professional document workflow and printing applications for office, print-room and transactions. Next to DDS printers, Océ is the global market leader in systems for the production and management of wide format technical documentation packages for architects, engineers, construction companies and manufacturers.

The academic partners are Delft University of Technology, Eindhoven University of Technology, Radboud University Nijmegen, and University of Twente. For part of the project time, researchers are co-located at the ESI facilities or at Océ in Venlo. Octopus started in July 2007, and is partly funded by the Dutch Government.

Publications

Octopus publications

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