Abstract
Reliability models rarely incorporate the uncertainty that is present in most of the reliability parameters, which is an important limitation for the managers of production system. This paper presents a fuzzy-probabilistic methodology that was developed to analyse production systems. The methodology employs probabilistic theory to represent the stochastic behaviour of the failure and repair processes and fuzzy sets to represent uncertainty in the parameters. This approach is based on a fuzzy reliability analysis from which is possible to obtain the fuzzy downtime function of a system in a given period of analysis. This function is a crucial element to obtain two performance measures: a financial measure (the fuzzy cost concerning failures of a production system) and a quality of service measure (the fuzzy frequency of failure on deliveries), as it will be illustrated in the final part of the paper through a practical example.

Abstract
The paper presents a methodology for the analysis of just-in-time production systems that are expected to deliver a fixed quantity of parts to its customers on a periodical basis, and whose equipment is submitted to random failure and repair processes. The methodology is based on the determination of the density function of T-H, the cumulated halting time of the production system between deliveries. The paper firstly shows how this function can be obtained from the internal structure of the system and individual equipment failure processes. Then, it shows how the reliability of the deliveries, and several production costs, e.g., extra work, delivery failures penalties, loss of sales profit, and safety stocks, may be assessed using this function. The practical application and usefulness of the methodology is illustrated in the final part of the paper for a typical production system of the automotive industry.

Abstract
This paper describes a mathematical formulation for the active/reactive dispatch in electricity markets, including a number of issues present in market models used in several countries. Traditional market approaches are implemented considering a sequence of activities namely in terms of active power dispatch and ancillary services. However, these two problems are coupled in the sense that dispatching reactive power is not independent from the active power scheduling of generators. The proposed model admits that it is known the purely economic pool dispatch together with bilateral contracts and then it aims at dispatching reactive resources considering voltage and branch limit constraints and constraints reflecting the alternator capability curve. As a sub-result, this formulation also outputs nodal active and reactive marginal prices that can be useful to build tariff schemes. Finally, the paper includes a case study based on the IEEE 30 bus/41 branch system to illustrate the obtained results and their interest for electricity markets.

Abstract
This paper presents a mathematical formulation for the active/reactive dispatch in electricity markets, recognizing that the typical sequential activities organized in terms of pool markets and the dispatch of ancillary services may lead to economic inefficiencies or technical difficulties. The developed model admits that it is known the purely economic pool dispatch and then it aims at dispatching reactive resources considering voltage and branch limit constraints and constraints reflecting the alternator capability curve. We also admitted that some constraints have a soft nature and used a symmetrical fuzzy decision formulation to model this aspect within an SLP based algorithm. Finally, the paper includes a case study based on the IEEE 24 bus/38 branch system to illustrate the results obtained with the developed approach. © Copyright KTH 2006.

Abstract
This paper presents a mathematical formulation for the active/reactive dispatch in electricity markets, recognizing that the typical sequential activities organized in terms of pool markets and the dispatch of ancillary services may lead to economic inefficiencies or technical difficulties. The developed model admits that it is known the purely economic pool dispatch and then it aims at dispatching reactive resources considering voltage and branch limit constraints and constraints reflecting the alternator capability curve. We also admitted that some constraints have a soft nature and used a symmetrical fuzzy decision formulation to model this aspect within an SLP based algorithm. Finally, the paper includes a case study based on the IEEE 24 bus/38 branch system to illustrate the results obtained with the developed approach.

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.