Cookies
O website necessita de alguns cookies e outros recursos semelhantes para funcionar. Caso o permita, o INESC TEC irá utilizar cookies para recolher dados sobre as suas visitas, contribuindo, assim, para estatísticas agregadas que permitem melhorar o nosso serviço. Ver mais
Aceitar Rejeitar
  • Menu
Publicações

Publicações por SYSTEM

2022

First-mile logistics parcel pickup: Vehicle routing with packing constraints under disruption

Autores
Gimenez Palacios, I; Parreno, F; Alvarez Valdes, R; Paquay, C; Oliveira, BB; Carravilla, MA; Olivera, JF;

Publicação
TRANSPORTATION RESEARCH PART E-LOGISTICS AND TRANSPORTATION REVIEW

Abstract
First-mile logistics tackles the movement of products from retailers to a warehouse or distri-bution centre. This first step towards the end customer has been pushed by large e-commerce platforms forming extensive networks of partners and is critical for fast deliveries. First-mile pickup requires efficient methods different from those developed for last-mile delivery, among other reasons due to the complexity of cargo features and volume - increasing the relevance of advanced packing methods. More importantly, the problem is essentially dynamic and the pickup process, in which the vehicle is initially empty, is much more flexible to react to disruptions arising when the vehicles are en route. We model the static first-mile pickup problem as a vehicle routing problem for a hetero-geneous fleet, with time windows and three-dimensional packing constraints. Moreover, we propose an approach to tackle the dynamic problem, in which the routes can be modified to accommodate disruptions - new customers' demands and modified requests of known customers that are arriving while the initially established routes are being covered. We propose three reactive strategies for addressing the disruptions depending on the number of vehicles available, and study their results on a newly generated benchmark for dynamic problems. The results allow quantifying the impact of disruptions depending on the strategy used and can help the logistics companies to define their own strategy, considering the characteristics of their customers and products and the available fleet.

2022

The two-dimensional cutting stock problem with usable leftovers: mathematical modelling and heuristic approaches

Autores
do Nascimento, DN; Cherri, AC; Oliveira, JF;

Publicação
OPERATIONAL RESEARCH

Abstract
Different variations of the classic cutting stock problem (CSP) have emerged and presented increasingly complex challenges for scientists and researchers. One of these variations, which is the central subject of this work, is the two-dimensional cutting stock problem with usable leftovers (2D-CSPUL). In these problems, leftovers can be generated to reduce waste. This technique has great practical importance for many companies, with a strong economic and environmental impact. In this paper, a non-linear mathematical model and its linearization are proposed to represent the 2D-CSPUL. Due to the complexity of the model, a heuristic procedure was also proposed. Computational tests were performed with instances from the literature and randomly generated instances. The results demonstrate that the proposed model and the heuristic procedure satisfactorily solve the problem, proving to be adequate and beneficial tools when applied to real situations.

2022

Variable fixing heuristics for the capacitated multicommodity network flow problem with multiple transport lines, a heterogeneous fleet and time windows

Autores
Guimaraes, LR; de Sousa, JP; Prata, BD;

Publicação
TRANSPORTATION LETTERS-THE INTERNATIONAL JOURNAL OF TRANSPORTATION RESEARCH

Abstract
In this paper, we investigate a new variant of the multi-commodity network flow problem, taking into consideration multiple transport lines and time windows. This variant arises in a city logistics environment, more specifically in a long-haul passenger transport system that is also used to transport urban freight. We propose two mixed integer programming models for two objective functions: minimization of network operational costs and minimization of travel times. Since the problems under study are NP-hard, we propose three size reduction heuristics. In order to assess the performance of the proposed algorithms, we carried out computational experiments on a set of synthetic problem instances. We use the relative percentage deviation as performance criterion. For the cost objective function, a LP-and-Fix algorithm outperforms other methods in most tested instances, but for the travel time, a hybrid method (size reduction with LP-and-Fix algorithm) is, in general, better than other approaches.

2022

The impact of video lecture capture on student attainment and achievement of intended learning outcomes

Autores
Remiao, F; Carmo, H; Gomes, M; Silva, R; Costa, VM; Carvalho, F; Bastos, MD;

Publicação
PHARMACY EDUCATION

Abstract
Background: The multimedia capturing of live lectures has increased within higher education institutions, even in the pre-COVID-19 period. Despite student satisfaction, the video lecture capture (VLC) influence on students' attainment and achievement of intended learning outcomes is controversial. Methods: To explore the impact of VLC, a cross-sectional study across 2016/17 (n=209 students) and 2017/18 (n=206 students) was conducted in the course of Mechanistic Toxicology in Pharmaceutical Education. Results: The results showed that 73% and 90% of the assessed students entirely viewed the videos of theoretical (550 minutes) and practical/laboratory classes (250 minutes), respectively. VLC impacted student attainment and the achievement of intended learning outcomes on the capacity to understand the subjects and apply knowledge. Conclusion: The effectiveness of VLC is to be considered under the framework of constructive alignment and the specificities of the course.

2022

Portuguese textile association fostering the internationalisation of small and medium-sized enterprises

Autores
Costa, E; Soares, AL; de Sousa, JP; Elo, M; Silva, SCE;

Publicação
INTERNATIONAL JOURNAL OF ENTREPRENEURSHIP & SMALL BUSINESS

Abstract
The support and influence of industrial business associations (IBAs) for the internationalisation process of small and medium-sized enterprises (SMEs) is questioned. This qualitative case study on the textile industry in Portugal illustrates how SMEs are influenced by their IBA. Findings suggest that it has a preponderant role in supporting the international expansion of associated SMEs. Particularly, the promotion and organisation of trade fairs seem to foster first entries and continuous international expansion in the same way the IBA seems to influence their foreign market selection. However, SMEs feel that the IBA’s work could still be improved by their facilitating more matchmaking processes, promoting collaborations, improving their seizing of available internationalisation opportunities, and providing more information about agents and distributors in foreign markets. Thus, we can say that, despite the internet and global opportunities that firms can directly benefit from, the role of IBAs is still relevant for SME’s internationalisation, and there is still room for improvement.

2022

On the use of sociotechnical systems design in industry: digital transformation processes and artifacts

Autores
Rebentisch E.S.; Soares A.L.; Rhodes D.H.; Zimmermann R.A.; Cardoso J.L.F.P.;

Publicação
CEUR Workshop Proceedings

Abstract
Digital transformation is a broad description of efforts to introduce new technologies within and across organizations with the potential to revolutionize the way they function and perform. Digital transformation may be addressed at multiple levels of analysis, and this paper focuses on the enterprise level. This includes the organization, its people, systems, tools and technologies, and suppliers and partners that combined create valued outcomes that sustain the enterprise and advance its objectives. Collectively, this is a complex sociotechnical system (STS), and digital transformation is an intervention in a STS of potentially profound scope. Classical STS theory emerged from analysis of individuals and work groups and principles have been defined for the design of work systems at that level. We explore how STS design principles may be applied to the enterprise-level challenges associated with digital transformation. We present an enterprise-level framework that describes a process and methods that are consistent with STS design principles and illustrates how existing systems analysis methods and artifacts may be used to design an enterprise level STS. We review some artifacts employed in digital transformation efforts, including enterprise reference architectures, to better understand how they might function as means to foster communication and collaboration across multiple disciplines and domains in the STS design process.

  • 90
  • 388