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Publications

2022

2-echelon lastmile delivery with lockers and occasional couriers

Authors
Dos Santos, AG; Viana, A; Pedroso, JP;

Publication
TRANSPORTATION RESEARCH PART E-LOGISTICS AND TRANSPORTATION REVIEW

Abstract
We propose a new approach for the lastmile delivery problem where, besides serving as collecting points of orders for customers, parcel lockers are also used as transshipment nodes in a 2-echelon delivery system. Moreover, we consider that a customer (occasional courier) visiting a locker may accept a compensation to make a delivery to another customer on their regular traveling path. The proposed shared use of the locker facilities - by customers that prefer to self-pick up their orders, and also as a transfer deposit for customers that prefer home delivery - will contribute to better usage of an already available storage capacity. Furthermore, the use of occasional couriers (OCs) brings an extra layer of flexibility to the delivery process and may positively contribute to achieving some environmental goals: although non-consolidation of deliveries may, at first sight, seem negative, by only considering OCs that would go to the locker independently of making or not a delivery on their way home, and their selection being constrained by a maximum detour, the carbon footprint can be potentially reduced when compared to that of dedicated vehicles. We present a mixed-integer linear programming formulation for the problem that integrates three delivery options - depot to locker, depot to locker followed by final delivery by a professional fleet, and depot to locker followed by final delivery by an OC. Furthermore, to assess the impact of OCs' no show on the delivery process, we extend the formulation to re-schedule the delivery of previous undelivered parcels, and analyze the impact of different no-show rates. Thorough computational experiments show that the use of OCs has a positive impact both on the delivery cost and on the total distance traveled by the dedicated fleets. Experiments also show that the negative impact of no-shows may be reduced by using lockers with higher capacities.

2022

Visual notations in container orchestrations: an empirical study with Docker Compose

Authors
Piedade, B; Dias, JP; Correia, FF;

Publication
SOFTWARE AND SYSTEMS MODELING

Abstract
Container orchestration tools supporting infrastructure-as-code allow new forms of collaboration between developers and operatives. Still, their text-based nature permits naive mistakes and is more difficult to read as complexity increases. We can find few examples of low-code approaches for defining the orchestration of containers, and there seems to be a lack of empirical studies showing the benefits and limitations of such approaches. We hypothesize that a complete visual notation for Docker-based orchestrations could reduce the effort, the error rate, and the development time. Therefore, we developed a tool featuring such a visual notation for Docker Compose configurations, and we empirically evaluated it in a controlled experiment with novice developers. The results show a significant reduction in development time and error-proneness when defining Docker Compose files, supporting our hypothesis. The participants also thought the prototype easier to use and useful, and wanted to use it in the future.

2022

Planeamento e contolo da produção: uma visão integrada

Authors
Ávila, Paulo; Bastos, João; Cavaco, Ismael;

Publication

Abstract
Este livro é o resultado do arranjo e compilação de textos didáticos produzidos ou adaptados pelos seus autores para apoio a unidades curriculares dos mestrados em Engenharia Mecânica - Gestão Industrial e Engenharia Eletrotécnica e Computadores – Sistemas de Planeamento Industrial, do Instituto Superior de Engenharia do Politécnico do Porto. Esses textos foram revistos e reorganizados, com vista, não só a manterem a função original de ajuda à formação de estudantes afetos a esta área do conhecimento, como também a constituírem uma referência de conhecimentos para quem deseje iniciar-se nestes temas; procuram ainda ser uma base de consulta e informação para engenheiros ou outros profissionais com funções na gestão da produção. O livro percorre os marcos mais significativos da trajetória histórica da gestão da produção, com particular foco no planeamento e controlo da produção, procurando interpretar e tornar compreensível a sua evolução, e relevando, sempre que oportuno, a influência da tecnologia nos modelos de gestão, e sua interligação. Começa por uma referência à tipologia dos sistemas de produção no capítulo I e aborda, no capítulo II, as principais funções do planeamento, programação e controlo da produção em contexto MRP, normalmente considerada uma visão mais clássica do tema. Outras duas aproximações com expressividade, a Teoria das Restrições e o JIT/Lean, são abordadas nos capítulos III e IV respetivamente. No capítulo V, o livro finaliza o seu conteúdo com uma breve referência a sistemas de informação empresariais, particularmente vocacionados para contextos de produção. Os autores expressam o seu agradecimento a todos os colegas, alunos e editor, que, com os seus contributos, permitiram chegar ao documento que agora disponibilizamos. Esperamos que lhe seja útil, prezado leitor, que suscite em si a mesma satisfação que o seu longo processo de compilação nos proporcionou, e que possa vir a ser, em próxima revisão, enriquecido com as valiosas críticas, sempre bem-vindas, que haja por bem dedicar-lhe.

2022

Joint Energy and Performance Aware Relay Positioning in Flying Networks

Authors
Rodrigues, H; Coelho, A; Ricardo, M; Campos, R;

Publication

Abstract
<div>Unmanned Aerial Vehicles (UAVs) have emerged as suitable platforms for transporting and positioning communications nodes on demand, including Wi-Fi Access Points and cellular Base Stations. This paved the way for the deployment of flying networks capable of temporarily providing wireless connectivity and reinforcing coverage and capacity of existing networks. Several solutions have been proposed for the positioning of UAVs acting as Flying Access Points (FAPs). Yet, the positioning of Flying Communications Relays (FCRs) in charge of forwarding the traffic to/from the Internet has not received equal attention. In addition, state of the art works are focused on optimizing both the flying network performance and the energy-efficiency from the communications point of view, leaving aside a relevant component: the energy spent for the UAV propulsion.</div><div>We propose the Energy and Performance Aware relay Positioning (EPAP) algorithm. EPAP defines target performance-aware Signal-to-Noise Ratio (SNR) values for the wireless links established between the FCR UAV and the FAPs and, based on that, computes the trajectory to be completed by the FCR UAV so that the energy spent for the UAV propulsion is minimized. EPAP was evaluated in terms of both the flying network performance and the FCR UAV endurance, considering multiple networking scenarios. Simulation results show gains up to 25% in the FCR UAV endurance, while not compromising the Quality of Service offered by the flying network.</div>

2022

Lung Segmentation in CT Images: A Residual U-Net Approach on a Cross-Cohort Dataset

Authors
Sousa, J; Pereira, T; Silva, F; Silva, MC; Vilares, AT; Cunha, A; Oliveira, HP;

Publication
APPLIED SCIENCES-BASEL

Abstract
Lung cancer is one of the most common causes of cancer-related mortality, and since the majority of cases are diagnosed when the tumor is in an advanced stage, the 5-year survival rate is dismally low. Nevertheless, the chances of survival can increase if the tumor is identified early on, which can be achieved through screening with computed tomography (CT). The clinical evaluation of CT images is a very time-consuming task and computed-aided diagnosis systems can help reduce this burden. The segmentation of the lungs is usually the first step taken in image analysis automatic models of the thorax. However, this task is very challenging since the lungs present high variability in shape and size. Moreover, the co-occurrence of other respiratory comorbidities alongside lung cancer is frequent, and each pathology can present its own scope of CT imaging appearances. This work investigated the development of a deep learning model, whose architecture consists of the combination of two structures, a U-Net and a ResNet34. The proposed model was designed on a cross-cohort dataset and it achieved a mean dice similarity coefficient (DSC) higher than 0.93 for the 4 different cohorts tested. The segmentation masks were qualitatively evaluated by two experienced radiologists to identify the main limitations of the developed model, despite the good overall performance obtained. The performance per pathology was assessed, and the results confirmed a small degradation for consolidation and pneumocystis pneumonia cases, with a DSC of 0.9015 +/- 0.2140 and 0.8750 +/- 0.1290, respectively. This work represents a relevant assessment of the lung segmentation model, taking into consideration the pathological cases that can be found in the clinical routine, since a global assessment could not detail the fragilities of the model.

2022

A Highly Customizable Information Visualization Framework

Authors
Spínola, L; Silva, DC; Reis, LP;

Publication
Computational Science - ICCS 2022 - 22nd International Conference, London, UK, June 21-23, 2022, Proceedings, Part II

Abstract
The human brain can quickly become overwhelmed by the amounts of data computers can process. Consequently, data abstraction is necessary for a user to grasp information and identify valuable patterns. Data is usually abstracted in a pictorial or graphical format. Nowadays, users demand more personalization from the systems they use. This work proposes a user-centered framework that aims to ease creating visualizations for the developers of a platform while offering the end-user a highly customizable experience. The conceptualized solution was prototyped and tested to ensure the information about the data is transmitted to the user in a quick and effective manner. The results of a user study showed that users are pleased with the usability of the prototype and prove that they desire control over the configuration of their visualizations. This work not only confirmed the usefulness of previously explored personalization options for visual representations, but also explored promising new personalization options. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

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