Abstract

Abstract

Abstract
This paper presents a modified negative selection algorithm for the diagnosis of disturbance in distribution electrical systems. This study analyzes voltage disturbances and high-impedance faults, based on three phase current and voltage electric measures, which are obtained at the substations. The principal application is to support operation decision aid during faults, as well as to supervise the protection system. To evaluate the performance of the proposed method, simulations were executed using the EMTP software for a distribution test system containing 134 bus. The results obtained were compared with the specialized literature.

Abstract
Production and distribution problems with perishable goods are common in many industries. For the sake of the competitiveness of the companies, the supply chain planning of products with restricted lifespan should be addressed with an integrated approach. Particularly, at the operational level, the sizing and scheduling of production lots have to be decided together with vehicle routing decisions to satisfy the customers. However, such joint decisions make the problems hard to solve for industries with a large product portfolio. This paper proposes an adaptive large neighbourhood search (ALNS) framework to tackle the problem. This metaheuristic is well known to be effective for vehicle routing problems. The proposed approach relies on mixed-integer linear programming models and tools. The ALNS outperforms traditional procedures of the literature, namely, exact methods and fix-and-optimize, in terms of quality of the solution and computational time of the algorithms. Nine in ten runs of ALNS yielded better solutions than traditional procedures, outperforming on average 12.7% over the best solutions provided by the latter methods.

Abstract
This paper presents an algorithm capable of generating smooth, feasible paths for an any-shape non-holonomic mobile robot, taking into account orientation restrictions, with the aim of navigating close to obstacles. Our contribution consists in an extension of the A* algorithm in a cell decomposition, where besides its position, the orientation of the platform is also considered when searching for a path. This is achieved by constructing 16 layers of orientations and only visiting neighbor layers when searching for the lowest cost. To simplify collision checking, the robot's footprint is used to inflate obstacles, yet, to allow the robot to find paths close to obstacles, the actual footprint of the robot must used. By discretizing the orientation space into layers and computing an oriented footprint for each layer, the actual footprint of the robot is used, increasing the configuration space without becoming computationally expensive. The path planning algorithm was developed under the EU-funded project CARLoS(1) and was implemented in a stud welding robot simulated within a naval industry environment, validating our approach.

Abstract
Purpose– The purpose of this paper is to characterize the knowledge flow between companies and universities based on national and sectoral systems of innovation perspective. It is argued here that high-tech sectors can describe a knowledge flow mainly based on scientific research, while sectors with lower technological impact may establish relations based on technical needs.Design/methodology/approach– A case study research was conducted in the horticulture and aerospace sectors in Brazil. Thirteen interviews were performed with chief executive officer’s and academic researchers from both fields.Findings– Results demonstrated differences in technology development and knowledge infrastructure when comparing both sectors, reflecting the impacts of national and sectoral systems of innovation. The horticulture sector presented technological limitations due to restricted eating habits, logistics, knowledge development at universities and difficulties on the establishment of partnerships between local companies and Embrapa, the main public research centre. Such restrictions limit academic activities while companies look for research partnerships abroad. Space industry also has limited technological development due to international embargoes and lack of research alignment between companies and universities. Companies end up developing research activities internally, usually funded by governmental tenders.Research limitations/implications– The horticulture sector has limitations, as it is not the main agriculture area in science and technology applications. Future studies may analyse areas like soy beans, sugar cane and coffee, which may present differences specially regarding sectoral systems of innovation.Originality/value– The finding of this paper may influence the review of sectoral innovation policies, improving the development of local research activities which may be a source of valuable knowledge to companies. It also demonstrates the importance of the knowledge flow to improve sector’s technology level.