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Publications

2021

A new model for location-allocation problem based on sectorization

Authors
Teymourifar, Aydin; Rodrigues, Ana Maria; Ferreira, José Soeiro;

Publication
Engineering World

Abstract
Many models have been proposed for the location-allocation problem. In this study, based on sectorization concept, we propose a new single-objective model of this problem, in which, there is a set of customers to be assigned to distribution centres (DCs). In sectorization problems there are two important criteria as compactness and equilibrium, which can be defined as constraints as well as objective functions. In this study, the objective function is defined based on the equilibrium of distances in sectors. The concept of compactness is closely related to the accessibility of customers from DCs. As a new approach, instead of compactness, we define the accessibility of customers from DCs based on the covering radius concept. The interpretation of this definition in real life is explained. As another contribution, in the model, a method is used for the selection of DCs, and a comparison is made with another method from the literature, then the advantages of each are discussed. We generate benchmarks for the problem and we solve it with a solver available in Python’s Pulp library. Implemented codes are presented in brief.

2021

Preface

Authors
Gruschka N.; Antunes L.F.C.; Rannenberg K.; Drogkaris P.;

Publication
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Abstract

2021

Hybrid stochastic/robust optimization model for resilient architecture of distribution networks against extreme weather conditions

Authors
Shahbazi, A; Aghaei, J; Pirouzi, S; Shafie khah, M; Catala, JPS;

Publication
INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS

Abstract
This paper expresses the planning model of the backup distributed generation (DG) and lines hardening and tie lines in distribution networks according to resilient architecture (RA) strategy under natural disaster conditions such as earthquakes and floods. Indeed, the proposed deterministic problem of resilient distribution system planning considers the minimization of the daily investment, operation and resiliency (repair and load shedding) costs as objective functions subject to constraints of AC power flow equations, system operation limits, planning and operation model of backup DG and hardening and tie lines, as well as network reconfiguration formulation. The problem formulation is based on a mixed integer non-linear programming (MINLP) model, which is converted to a mixed integer linear programming (MILP) model on the basis of Benders decomposition (BD) approach using linearization approaches to achieve the optimal solution with the lower computational efforts and error. Besides, a hybrid stochastic/robust optimization (HSRO) based on the bounded uncertainty-based robust optimization (BURO) and a scenario-based stochastic optimization is used to model the uncertainties of load, energy price and availability of the network equipment under the extreme weather conditions. Finally, the proposed RA strategy is applied on 33-bus and 119-bus distribution test systems to investigate its capabilities in different case studies.

2021

Robotic grasping: from wrench space heuristics to deep learning policies

Authors
de Souza, JPC; Rocha, LF; Oliveira, PM; Moreira, AP; Boaventura Cunha, J;

Publication
ROBOTICS AND COMPUTER-INTEGRATED MANUFACTURING

Abstract
The robotic grasping task persists as a modern industry problem that seeks autonomous, fast implementation, and efficient techniques. Domestic robots are also a reality demanding a delicate and accurate human-machine interaction, with precise robotic grasping and handling. From decades ago, with analytical heuristics, to recent days, with the new deep learning policies, grasping in complex scenarios is still the aim of several works' that propose distinctive approaches. In this context, this paper aims to cover recent methodologies' development and discuss them, showing state-of-the-art challenges and the gap to industrial applications deployment. Given the complexity of the related issue associated with the elaborated proposed methods, this paper formulates some fair and transparent definitions for results' assessment to provide researchers with a clear and standardised idea of the comparison between the new proposals.

2021

PLAY for LEARNING: Serious Games to Assist Learning of Basic Didactic Concepts: A Pilot Study

Authors
Rocha, T; Barroso, J;

Publication
HCI in Games: Serious and Immersive Games - Third International Conference, HCI-Games 2021, Held as Part of the 23rd HCI International Conference, HCII 2021, Virtual Event, July 24-29, 2021, Proceedings, Part II

Abstract
In this paper, the study of the design and implementation of a gamebased application for learning new basic concepts and/or re-learning these concepts within a cognitive rehabilitation perspective, is presented. Specifically, in this first version, the topics considered were: colours, animals, objects, and vehicles. The solution was developed to be usable and accessible to two user groups, children with special education needs and seniors in need of cognitive training and/or rehabilitation. The two main goals are: (1) to develop a game-based interface for the two specific user groups – children with special educational needs and seniors; (2) and, assess user engagement and acceptance. To achieve the first goal a universal design methodology was followed. For the later, we performed a preliminary usability assessment. Specifically, a Cognitive Walkthrough reinforced with a post-test semi-structured interviews was conducted. Overall results showed a good user engagement and acceptance. The gamebased solution seemed to facilitated children’ apprenticeship of basic contents and the helped in the cognitive rehabilitation by the seniors. The preliminary results indicated the solution could be used as an assistive tool, in a special education or in rehabilitation contexts, with tutors, teachers or clinicians; but also, in a more without obstruction and autonomous interaction, at home. © Springer Nature Switzerland AG 2021.

2021

Allocation of FCLs in Transmission Networks with High Penetration of DGs: A Two-Stage Approach

Authors
Jarrahi, MA; Roozitalab, F; Arefi, MM; Mohammadi, M; Javadi, MS; Catalao, JPS;

Publication
2021 INTERNATIONAL CONFERENCE ON SMART ENERGY SYSTEMS AND TECHNOLOGIES (SEST)

Abstract
Fault current limiters (FCLs) are getting high-degree of attention since they can properly overcome the transient conditions of modern power systems. FCLs have the ability to limit the short-circuit currents before reaching to its maximum value so that they can be cut off by the available switches. In fact, FCLs show negligible resistance in the normal operation, but their resistance suddenly increases with a short-circuit and prevents it from rising. The technical and economic benefits of FCLs in power systems depend on their number, locations and optimal structural parameters. In this paper, a two-stage approach is proposed for determining the number, location and impedance of FCLs in the transmission network with high penetration of distributed generations (DGs). The suggested algorithm determines the number and locations of FCLs in the first step using a sensitivity based technique and the value of FCL impedance is chosen in the second step utilizing an optimization objective function. The improved grey wolf optimizer (IGWO) is developed to solve the optimization problem which its main objective is reducing the short-circuit level of the network. The proposed approach is assessed on the IEEE-30 bus transmission network considering the effects of different kind of DGs. The results shown that FCLs can significantly reduce the short-circuit level of the network along with other advantages.

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