Abstract

Abstract
Nowadays, it has been observed an increasing awareness and understanding on the subject of sustainable companies and business models, addressing multi-disciplinary approaches that cover not only economical problems, but also social and environmental challenges. Supply chains and especially collaborative networks managers are increasingly aware of these sustainability issues, continuously seeking to meet current human needs while preserving environmental safety. Only this way, focusing on its sustainable growing, it is possible to preserve companies' steadiness. In order to achieve this goal, sustainable networks must ensure that each partner is fully aligned and committed with economic, environmental and social axes that rule the network operational behaviour. Nevertheless, in order to achieve this level of maturity within such complex and turbulent environments, organisations need to improve the quality of their performance assessment approaches, integrating the different sustainability perspectives. To accomplish this, it is critical to establish specific indicators responsible to formalise and evaluate partners' behaviour, according to well-identified objectives, as well as fuse this information in a comprehensive and user-friendly way. This paper presents a new approach, based on a fuzzy logic-based algorithm, for sustainable network performance and risk assessment. © 2016 Inderscience Enterprises Ltd.

Abstract
This paper analyzes the optimal planning and operation of aggregated distributed energy resources (DER) with participation in the electricity market. Aggregators manage their portfolio of resources in order to obtain the maximum benefit from the grid, while participating in the day-ahead wholesale electricity market. The goal of this paper is to propose a model for aggregated DER systems planning, considering its participation in the electricity market and its impact on the market price. The results are the optimal planning and management of DER systems, and the appropriate energy transactions for the aggregator in the wholesale day-ahead market according to the size of its aggregated resources. A price-maker approach based on representing the market competitors with residual demand curves is followed, and the impact on the price is assessed to help in the decision of using price-maker or price-taker approaches depending on the size of the aggregated resources. A deterministic programming problem with two case studies (the average scenario and the most likely scenario from the stochastic ones), and a stochastic one with a case study to account for the market uncertainty are described. For both models, market scenarios have been built from historical data of the Spanish system. The results suggest that when the aggregated resources have enough size to follow a price-maker approach and the uncertainty of the markets is considered in the planning process, the DER systems can achieve up to 50% extra economic benefits, depending on the market share, compared with a non aggregated business-as-usual approach (not implementing DER systems).

Abstract

Abstract
This survey presents a literature review on the machine and control systems applied in friction stir welding (FSW) with a special focus on the new trends, i.e., using robots and force control. The physical process of FSW is described and the main parameters that are relevant to select a machine and establish a control system are highlighted. The paper reviews in detail the role of the following parameters of a given machine for FSW: force, stiffness, accuracy, sensing, decision-making and flexibility capabilities. They will be compared in terms of the different machines, namely the conventional machine tools, dedicated FSW machines, parallel kinematic robots, and articulated robots. It is stated that articulated arm robots have enormous potentialities in the industrialization of the process, but they also have important limitations namely related to positional accuracy. A quality FSW weld produced by a robot depends on the fine tuning of some process parameters and force/motion control capabilities. Control systems can deal with these limitations. The different approaches to the control systems applied in FSW are presented and their advantages/drawbacks are discussed.

Abstract
Destination image is critical for the development of tourism, particularly for islands where the scarcity of resources requires special care in focusing on the few determinants the islands have. This paper aims to describe the most perceived image determinants by tourists of Cape Verde. Based on a convenience sample of 627 international tourists, a second order factor analysis model was validated through the model fit measures. Despite a scarcity of resources, the results suggest that the image of Cape Verde is a multidimensional construct comprising five factors: natural attractions, man-made attractions, amenities, culture and price. Among these, the man-made and natural attractions as well as amenities are the most important image determinants for Cape Verde. Potentially there is a plurality of dimensions to be appreciated in the positioning process. Challenging many studies which have almost exclusively emphasised the attractions of natural resources, the tourism sector of this destination can offer a major and more flexible competitive advantage. The results may be helpful to other African countries which share similar developmental constraints with Cape Verde. © 2017 Nova Science Publishers, Inc.