Future manufacturing systems need to cope with frequent changes and disturbances. As such, their control requires constant adaptation and high flexibility. Holonic manufacturing is a highly distributed control paradigm that promises to handle these problems successfully. It is based on the concept of autonomous cooperating agents, called 'holons'. This paper gives an overview of the holonic reference architecture for manufacturing systems as developed at PMA-KULeuven. This architecture, called PROSA, consists of three types of basic holons: order holons, product holons, and resource holons. They are structured using the object-oriented concepts of aggregation and specialisation. Staff holons can be added to assist the basic holons with expert knowledge. The resulting architecture has a high degree of self-similarity, which reduces the complexity to integrate new components and enables easy reconfiguration of the system. PROSA shows to cover aspects of both hierarchical as well as heterarchical control approaches. As such, it can be regarded as a generalisation of the two former approaches. More importantly, PROSA introduces significant innovations: the system structure is decoupled from the control algorithm, logistical aspects can be decoupled from technical ones, and PROSA opens opportunities to achieve more advanced hybrid control algorithms.

Optical analysis of hydrogenated amorphous silicon (a-Si:H) solar cells with a periodic texture applied to the interfaces was carried out by two-dimensional optical simulator. The optical simulator solves the electromagnetic wave equations by means of finite element method using triangular elements for the discretization of space. The periodic texture with rectangular-like shape acts as a diffraction grating which scatters light into selective angles and thus gives a potential for significant prolongation of optical paths in thin absorber layers of the cells. Optimization of the geometrical parameters (period, height and duty-cycle) of the periodic texture was carried out in order to obtain the highest photocurrent from a-Si:H solar cells. The a-Si:H solar cell with the optimal periodic texture parameters (period of 300 nm, height of 300 nm and duty cycle of 50%) and the absorber layer thickness of 300 nm generates up to 35% more photocurrent in comparison to the cell with flat interfaces. The optical analysis demonstrates that the optimal periodic texture in the a-Si:H solar cell results in the best trade-off between the antireflection effect at front interfaces, light scattering efficiency and the absorption losses at realistic metal back contact.

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A new phase-transition mastering (PTM) process was developed for Blu-ray Disc read-only memory (BD-ROM) mastering. Results obtained with both a 266 and 405 nm laser beam recorder (LBR) are discussed in this paper. The feasibility of BD-ROM mastering was successfully demonstrated on both LBRs. With the insight that 25 Gbytes BD-ROM can be mastered with a 405 nm wavelength LBR, the availability of the 266 nm wavelength LBR opened the route to explore PTM of near-field data densities. First experiments indicate that the PTM process is also suitable for mastering data densities beyond 25 Gbytes data density.