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Publications

Publications by SYSTEM

2025

Deep Learning-Driven Integration of Multimodal Data for Material Property Predictions

Authors
Costa, V; Oliveira, JM; Ramos, P;

Publication
COMPUTATION

Abstract
Advancements in deep learning have revolutionized materials discovery by enabling predictive modeling of complex material properties. However, single-modal approaches often fail to capture the intricate interplay of compositional, structural, and morphological characteristics. This study introduces a novel multimodal deep learning framework for enhanced material property prediction, integrating textual (chemical compositions), tabular (structural descriptors), and image-based (2D crystal structure visualizations) modalities. Utilizing the Alexandriadatabase, we construct a comprehensive multimodal dataset of 10,000 materials with symmetry-resolved crystallographic data. Specialized neural architectures, such as FT-Transformer for tabular data, Hugging Face Electra-based model for text, and TIMM-based MetaFormer for images, generate modality-specific embeddings, fused through a hybrid strategy into a unified latent space. The framework predicts seven critical material properties, including electronic (band gap, density of states), thermodynamic (formation energy, energy above hull, total energy), magnetic (magnetic moment per volume), and volumetric (volume per atom) features, many governed by crystallographic symmetry. Experimental results demonstrated that multimodal fusion significantly outperforms unimodal baselines. Notably, the bimodal integration of image and text data showed significant gains, reducing the Mean Absolute Error for band gap by approximately 22.7% and for volume per atom by 22.4% compared to the average unimodal models. This combination also achieved a 28.4% reduction in Root Mean Squared Error for formation energy. The full trimodal model (tabular + images + text) yielded competitive, and in several cases the lowest, error metrics, particularly for band gap, magnetic moment per volume and density of states per atom, confirming the value of integrating all three modalities. This scalable, modular framework advances materials informatics, offering a powerful tool for data-driven materials discovery and design.

2025

Towards a Framework for Service Quality Improvement in Startup Companies

Authors
Feversani, DP; de Castro, MV; Marcos, E; Teixeira, JG;

Publication
PROCEEDINGS OF THE 58TH HAWAII INTERNATIONAL CONFERENCE ON SYSTEM SCIENCES

Abstract
Startups are vital to the economy and the digital future and are creators of around 50% of new jobs. Some studies indicate that around 90% of startups fail in their first months, mainly because they focus on launching products or services without adequate market validation. In addition, they have little or no experience in organisational management and lack the resources to apply quality models, which hinders their ability to face the challenges of a highly volatile and competitive environment. Therefore, this paper proposes the LightStartup framework, focused on startups in the service sector. LightStartup provides a lightweight, consistent and formalised process model, a process assessment model and a maturity model based on the ISO/IEC 33000 standard. LightStartup accompanies companies in transitioning from an informal management style to a formal and long-lasting management system, covering the management of services, people, customers and organisational governance.

2025

The dual role of customer-citizen engagement for sustainability

Authors
de Matos, MA; Patrício, L; Teixeira, JG;

Publication
JOURNAL OF SERVICE THEORY AND PRACTICE

Abstract
Purpose Citizen engagement plays a crucial role in transitioning to sustainable service ecosystems. While customer engagement has been extensively studied in service research, citizen engagement has received significantly less attention. By synthesizing customer and citizen engagement literatures, this study develops an integrated framework to conceptually clarify the dual role of customer-citizen engagement for sustainability. Design/methodology/approach This study builds on a systematic literature review of customer engagement literature in service research and citizen engagement literature. Following a theory synthesis approach, we qualitatively analyzed 126 articles to develop an integrated conceptual framework of customer-citizen engagement for sustainability through a process of abductive reasoning. Findings The analysis showed that customer engagement and citizen engagement literatures have developed mostly separately but provide complementary views. While the customer engagement literature has traditionally focused on business-related facets, such as engagement with brands, the citizen perspective broadens the engagement scope to other citizens, communities and society in general. The integrated framework highlights the interplay between citizen and customer roles and the impact of their relationships with multiple objects on sustainability. Originality/value This integrated framework contributes to advancing our understanding of customer-citizen engagement, broadening the scope of subject-object engagement by examining the interplay between these roles in how they engage for sustainability and moving beyond the traditional dyadic perspective to a multi-level perspective of service ecosystems. This framework also enables the development of a set of research directions to advance the understanding of engagement in sustainable service ecosystems.

2025

Biomimicry for sustainability: Upframing service ecosystems

Authors
Gallan, S; Alkire, L; Teixeira, JG; Heinonen, K; Fisk, P;

Publication
AMS Review

Abstract
Amidst an urgent need for sustainability, novel approaches are required to address environmental challenges. In this context, biomimicry offers a promising logic for catalyzing nature’s wisdom to address this complexity. The purpose of this research is to (1) establish a biomimetic understanding and vocabulary for sustainability and (2) apply biomimicry to upframe service ecosystems as a foundation for sustainability. Our research question is: How can the principles of natural ecosystems inform and enhance the sustainability of service ecosystems? The findings highlight upframed service ecosystems as embodying a set of practices that (1) promote mutualistic interactions, (2) build on local biotic and abiotic components supporting emergence processes, (3) leverage (bio)diversity to build resilience, (4) foster resource sharing for regeneration, and (5) bridge individual roles to optimize the community rather than individual well-being. Our upframed definition of a service ecosystem is a system of resource-integrating biotic actors and abiotic resources functioning according to ecocentric principles for mutualistic and regenerative value creation. The discussion emphasizes the implications of this upframed definition for sustainability practices, advocating for a shift in understanding and interacting with service ecosystems. It emphasizes the potential for immediate mutualistic benefits and long-term regenerative impacts. © Academy of Marketing Science 2025.

2025

Structuring Complex System for Digital Twin Development: A Systematic Scoping Review

Authors
Ghanbarifard, R; Almeida, AH; Azevedo, A;

Publication
IEEE ACCESS

Abstract
Complex systems, characterised by high interconnectedness and unpredictability, demand structured approaches to support decision-making, system integration, and operational efficiency. This study aims to develop a comprehensive understanding of these systems to facilitate the implementation of Digital Twins (DTs) in Complex Operations Environments (COEs). A Systematic Literature Review (SLR), following PRISMA methodology, is conducted and complemented by a grounded theory approach to identify, organise, and synthesise system characteristics. The result is a hierarchical conceptualisation comprising eight core categories that capture the essential dimensions of complexity, including: Process and System Interoperability, Human Relationships, Behaviour/Nature, Products and Services, Multi-processes, Performance, System Structure, and Management and Skill Requirements. This framework offers a structured foundation for designing and implementing DT-based decision support in COEs.

2025

A 3D printing nesting algorithm with dynamic collision constraints

Authors
Rocha, P; Ramos, AG; Silva, E;

Publication
INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH

Abstract
Additive Layer Manufacturing, particularly Fused Deposition Modelling, faces significant batch loss risks during production. The traditional Concurrent Printing Mode produces all parts simultaneously (layer-by-layer, bottom-to-top), efficiently using printing space but risking complete batch failure if problems occur. In contrast, Sequential Printing Mode produces one part at a time, reducing the risk of total batch loss but utilising printing space less efficiently. In this work, we propose an algorithm that, given a set of parts, performs the nesting of the parts for Concurrent Printing Mode, and for the first time, for the Sequential Printing Mode. A no-fit polygon based approach is used to handle geometry between pairs of parts by using multiple horizontal 2D layer projections of 3D parts, to ensure non-overlapping constraints and prevent machine-part collisions. A Greedy Randomized Adaptive Search Procedure is proposed, tested and benchmarked against a commercial software, using a new set of real-world instances. The approach shows the ability to find high-quality solutions. The approach significantly reduces the number of batches, minimises waste, reduces manufacturing time, and promotes parts quality.

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