Abstract
This paper describes and evaluates the feasibility of control strategies to be adopted for the operation of a microgrid when it becomes isolated. Normally, the microgrid operates in interconnected mode with the medium voltage network; however, scheduled or forced isolation can take place. In such conditions, the microgrid must have the ability to operate stably and autonomously. An evaluation of the need of storage devices and load shedding strategies is included in this paper.

Abstract
A new concept to measure rotation angles based on a fiber-optic modal Mach-Zehnder interferometer is demonstrated by using a nonadiabatic taper cascaded with a long-period fiber grating. Information about the magnitude of the rotation angle can be obtained from the measurement of the interference pattern visibility, and under certain conditions it is also possible to obtain the sign of the rotation angle from the induced phase variation in the fiber interferometer. (c) 2006 Optical Society of America.

Abstract
Recent intrusion detection systems (IDS) use regular expressions instead of static patterns as a more efficient way to represent hazardous packet payload contents. This paper focuses on regular expressions pattern matching engines implemented in reconfigurable hardware. We present a Nondeterministic Finite Automata (NFA) based implementation, which takes advantage of new basic building blocks to support more complex regular expressions than the previous approaches. Our methodology is supported by a tool that automatically generates the circuitry for the given regular expressions, outputting VHDL representations ready for logic synthesis. Furthermore, we include techniques to reduce the area cost of our designs and maximize performance when targeting FPGAs. Experimental results show that our tool is able to generate a regular expression engine to match more than 500 IDS regular expressions (from the Snort ruleset) using only 25K logic cells and achieving 2 Gbps throughput on a Virtex2 and 2.9 on a Virtex4 device. Concerning the throughput per area required per matching non-Meta character, our design is 3.4 and 10x more efficient than previous ASIC and FPGA approaches, respectively.

Abstract
This chapter discusses the analysis of an enhanced collision resolution algorithm for the shared Ethernet networks, referred as the high priority binary exponential backoff (h-BEB). Such an algorithm allows for the coexistence of the Ethernet standard devices together with the modified (real-time) devices in the same network segment. Both the analytical and the simulation timing analysis show that the h-BEB algorithm assures a maximum access delay that is significantly smaller than that for the case of the standard Ethernet stations. Analyses of two cases were done. The analytical study for a heavily loaded network scenario shows that the maximum access delay for 95% of the messages is smaller than 1,86 ms. While, for more realistic load scenarios (intermediate load cases), the simulation analysis shows that the maximum access delay for 98% of the messages is always smaller than 1 ms. It also shows a nearly constant message transfer jitter, which is one order of magnitude smaller than the maximum access delay for 98% of the messages. The algorithm enables the traffic separation between the standard and the modified (real-time) stations, and is therefore able to guarantee a real-time communication behavior in the unconstrained traffic environments.

Abstract
Precomputed Radiance Transport (PRT) was introduced as a technique to enable interactive navigation and distant environmental real time relighting of rigid scenes. Evaluating radiance transport is, however, a computationally very demanding task, which precludes PRT's utilization during the model design phase, since the user must wait for long periods of time before being able to light and navigate within the model. This paper proposes and validates an approach to provide visual feedback to the user as soon as possible, within PRT context. By resorting to parallel processing and progressive refinement, the user is quickly presented with a lower lighting resolution of the virtual model. This is then progressively refined by incrementally increasing the number of incident directions taken into account on transport computations. PRT is, however, a complex algorithm that requires frequent collective communications of huge volumes of data, thus constraining the maximum achievable speedup on a parallel system. This issue is analysed and an alternative workload distribution is proposed and evaluated on a 12 node dual processor cluster. The final solution ensures a good resource utilization rate, reducing response times from dozens of seconds to a few hundred milliseconds. Copyright © 2006 by the Association for Computing Machinery, Inc.

Abstract
Purpose - To provide the basis for the development of a specific benchmarking methodology for the foundry industry. Design/methodology/approach - The methodology was developed with the support of the Portuguese Foundry Association (APF). The project was structured in two stages: developing the model for the performance assessment (including performance indicators specially designed for the foundry companies); and conducting a pilot benchmarking exercise in order to validate the model. Both stages received the contribution of eight relevant national foundries. Findings - Provides information about expectations of the benchmarking partners group. Make available a specific benchmarking model for assessing the foudries' performance based on critical factors. Provides foundry-oriented indicators. Confirms that benchmarking is a time-consuming tool, demanding continuous commitment of the top-managers. Research limitations/implications - A limitation of the study is the number of benchmarking partners (eight foundries). The statistical analysis of the results based on this small sample was not practicable, preventing the definition of the presumed causal relations between improvement practices and performance outcomes. Practical implications - The benchmarking model is now available at the APF. From now on, this institution can provide its members with a tool for promoting the co-operation among companies and to enhance and enlarge significantly the available information about this sector. This activity will, certainly, help to improve organisations' performance, upgrading the competitiveness of the metalcasting industry in Portugal. Originality/value - This paper helps the development of benchmarking in the metalcasting industry in which the number of published studies is very limited. © Emerald Group Publishing Limited.