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Publications

2025

The DDMRP Replenishment Model: An Assessment by Simulation

Authors
Fernandes, NO; Djabi, S; Thürer, M; Avila, P; Ferreira, LP; Carmo-Silva, S;

Publication
MATHEMATICS

Abstract
Demand-Driven Material Requirements Planning (DDMRP) has been proposed as a solution for managing uncertainty and variability in supply chains by combining decoupling, buffer management and demand-driven planning principles. A key element of DDMRP is its inventory replenishment model, which relies on dynamically adjusted inventory buffers rather than fixed stock levels. However, parameterization of these buffers often involves subjective choices, raising concerns about consistency and performance. This paper assesses the DDMRP replenishment model through discrete-event simulation of a multi-echelon, capacity-constrained production system. Two alternative formulations of the safety stock term in the red zone are compared: the original factor-based approach and a revised formula that incorporates measurable variability coefficients. While both safety stock formulations yield similar numerical results, the revised formula enhances transparency and reduces subjectivity. Assessing the impact of introducing a buffer for components in addition to a finished goods buffer further shows that the components buffer can reduce finished goods inventory requirements while maintaining service levels. These findings contribute to a better understanding of the DDMRP replenishment model, offering practical insights for parameter selection and supply chain design.

2025

RepliCo: Remote Collaboration over 3D Content in DeskVR through Miniature Replicas

Authors
Alves, N; Mendes, D; Rodrigues, R;

Publication
2025 INTERNATIONAL CONFERENCE ON GRAPHICS AND INTERACTION, ICGI

Abstract
Virtual Reality (VR) can be an excellent platform for collaborative work. However, standing in VR and gesturing in midair can be physically exhausting. We introduce RepliCo, a collaborative DeskVR approach focused on communication in the context of 3D content reviewing. Using an interactive surface and the world-in-miniature metaphor, it addresses common challenges in virtual collaboration, such as spatially referencing points of interest and user awareness. We conducted a user evaluation with 20 participants to assess the viability of our approach in both a large and a small environment. Results revealed that RepliCo efficiently allowed users to share points of interest in a user-friendly and physically undemanding manner. Although the larger model was identified as requiring more effort, there were few significant differences in task completion times, highlighting RepliCo's versatility.

2025

VR Training and Authoring Tool for Industrial Training Using Virtual Choreographies

Authors
Ferreira, A; Cassola, F;

Publication
Proceedings - 2025 IEEE International Symposium on Emerging Metaverse, ISEMV 2025

Abstract
Virtual Reality (VR) is a powerful tool for industrial training due to its capacity to simulate realistic, risk-free environments. However, creating VR training scenarios often requires significant technical expertise and large investments, limiting the technology's adoption. This paper presents a VR training platform that empowers trainers to author, test, and deliver immersive training procedures directly within a VR environment without writing code. It also gives trainees a place to practice and learn without consequences. A key feature is the integration of Virtual Choreographies, enabling trainers to define ordered procedures, record trainee attempts, more easily understand their actions, and automatically assess performance. A user study was conducted to evaluate usability, workflow clarity, and feature effectiveness. Results indicate strong usability and comprehension for non-expert users, and confirm the potential of Virtual Choreographies to guide and evaluate procedural training. The platform represents a step toward creating accessible, customizable VR training for industrial and educational settings. © 2025 IEEE.

2025

International Kidney Paired Donation Programs: Evolution and Practices of 4 Large Collaborations

Authors
Klimentova, X; Domínguez Gil, B; Viana, A; Manlove, D; Andersson, T; Ashkenazi, T; Berlakovich, GM; Böhmig, A; Burton, J; Coll Piera, E; Dittmer, I; Fiaschetti, P; Fronek, PJ; Hughes, PD; Ivo da Silva, M; Mor, E; Viklický, O; Weinreich, S; Ferrari, P;

Publication
Transplantation

Abstract
Kidney paired donation (KPD) programs are organized in various countries to facilitate the donation of kidneys from willing but incompatible donors by matching them with pairs in similar situations. These programs often struggle with an accumulation of difficult-to-match recipients and small pools of incompatible pairs. To address this, several international collaborations have emerged to expand the pool sizes and increase the number of transplants by “exchanging” donors’ kidneys across countries. We identified 4 established international KPD programs, each supported by protocols and agreements signed by the participating parties. Each program is presented separately, detailing its historical establishment, operational aspects, and statistics on pool characteristics and performance. Following this, we provide a comparative analysis of key aspects across the 4 programs. Each program has its unique context and specificities. Even though 3 of 4 collaborations started just before the COVID-19 pandemic, they have collectively facilitated >450 transplants. This underscores the importance of further developing these collaborations to share practices and experiences, and to facilitate more transplants, particularly for difficult-to-match recipients. Three of the 4 presented collaborations are either fully operated or led by European countries. This highlights the crucial role of ongoing international cooperation in the development of KPDs, in particular in Europe. By further promoting collaboration among countries, we can facilitate pan-European exchanges and improve access to live kidney transplants for patients in need. © 2025

2025

Re-planning e-Commerce Logistics Considering the Synergies Between Last-Mile Delivery Technologies

Authors
Silva, V; Fontes, T;

Publication
HUMAN-CENTRED TECHNOLOGY MANAGEMENT FOR A SUSTAINABLE FUTURE, VOL 2, IAMOT

Abstract
E-commerce popularity has increased the challenges of parcel deliveries, highlighting the urgency in addressing the sustainability of the last-mile, which is considered the most ineffective part of the supply chain and a source of environmental and social issues. Although different alternative last-mile technologies have already been proposed, they all imply complex trade-offs. This study explores how synergies between delivery technologies could improve last-mile logistics. It evaluates the trade-offs between electric vans, cargo bikes, and parcel lockers, and takes into account factors such as package size, consumer requirement, and urban context. The adoption of a combined delivery strategy suggests environmental and social benefits like the mitigation of congestion and emissions while ensuring advantages for companies due to streamlined operations and offering consumers a broader range of choices.

2025

Transversal Digital Marketing Curriculum Design

Authors
Pires, PB; Santos, JD; de Brito, PQ; Delgado, C;

Publication
MARKETING AND SMART TECHNOLOGIES, ICMARKTECH 2024, VOL 1

Abstract
The advent of new technologies has led to significant changes in the field of marketing, demanding a rethinking of existing knowledge and skills. This research proposes a set of transversal curricula in digital marketing. The methodology employed included an exploratory analysis of digital marketing courses offered at universities and major online platforms, focus groups, and interviews, conducted in four countries. The countries included in the study were Finland, Poland, the Netherlands, and Portugal. The findings indicated that an introductory course and specialization blocks would be beneficial. Social media, analytics, digital advertising, search engine optimization (SEO), digital marketing strategies, web content, e-mail marketing, customer experience, landing pages, user experience, leads, conversion rate optimization, and E-commerce were identified as the key subjects of study for the introductory course in digital marketing.

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