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Systems

Systems is an international, peer-reviewed, open access journal on systems theory in practice, including fields such as systems engineering management, systems based project planning in urban settings, health systems, environmental management and complex social systems, published monthly online by MDPI.
The International Society for the Systems Sciences (ISSS) is affiliated with Systems and its members receive a discount on the article processing charges.
Quartile Ranking JCR - Q1 (Social Sciences, Interdisciplinary)

All Articles (3,008)

Big data service providers (BDSPs) play a critical role in supporting the digital transformation of closed-loop supply chains (CLSCs). However, as the number of CLSC members increases, traditional coordination contracts become complex in the big data era, which challenges effective collaboration and contract implementation. To address this issue, this paper investigates the profit coordination problem in a CLSC with a BDSP, with the aim of lowering the contract implementation threshold and facilitating flexible adjustment of contract terms. This study applies the variational inequality method to derive the necessary conditions under which a CLSC with the participation of a BDSP achieves maximum system profit. The results indicate that these necessary conditions are as follows. First, the wholesale price is equal to the unit cost of new products. Second, the optimal payment level is positively correlated with production volume, unit cost savings, the BDSP marketing effort sensitivity coefficient, and the BDSP recycling effort sensitivity coefficient, while it is negatively correlated with the retail price sensitivity coefficient, the recycling price sensitivity coefficient, and the big data service cost coefficient.

1 January 2026

Operational Process of the CLSC. Note: The dashed line shows the indirect effect of BDSP’s service effort level on the retailer through increased demand.

Data-Driven Efficiency Analysis of EU Higher Education Systems Using Stochastic Frontier Models

  • Ioana-Alexandra Râlea,
  • Carmen Pintilescu and
  • Ștefănescu Iulia-Oana
  • + 1 author

This study investigates the efficiency of higher education systems across the 27 Member States of the European Union during the period 2017–2022, addressing increasing policy interest in data-driven decision support and optimization techniques for performance evaluation in education systems. Efficiency is assessed using Stochastic Frontier Analysis, an optimization-based econometric approach, applied to multiple output dimensions relevant to learning analytics: alignment between graduates’ skills and labour market requirements, scientific productivity measured by published articles, and the number of higher education graduates. The model incorporates key input variables, including the student–teacher ratio, public expenditure per student, research and development expenditure, and the number of academic staff, while controlling for real gross domestic product per capita. To support integrated efficiency measurement and information-based decision-making, multidimensional outcomes are aggregated into composite efficiency indices using entropy-based weighting. The results reveal substantial cross-country heterogeneity in efficiency across EU higher education systems, identifying a cluster of high-performing countries that consistently optimize scientific output and graduate production. Financial resources and academic staff availability emerge as significant drivers of efficiency, while skill matching to labour market demand remains a persistent structural challenge. By combining Stochastic Frontier Analysis with entropy-based aggregation, this study provides a robust data-driven decision support framework for efficiency assessment, offering valuable insights for education policy design, resource allocation, and learning-oriented system optimization.

31 December 2025

Accurate imputation of missing pavement-condition data is critical for proactive infrastructure management, yet it is complicated by spatial non-stationarity—deterioration patterns and data quality vary markedly across regions. This study proposes a Spatially Gated Mixture-of-Experts (SG-MoE) imputation model that explicitly encodes spatial heterogeneity by (i) clustering road segments using geographic coordinates and (ii) supervising a gating network to route each sample to region-specialized expert regressors. Using a large-scale national pavement management database, we benchmark SG-MoE against a strong baseline under controlled missingness mechanisms (MCAR: missing completely at random; MAR: missing at random; MNAR: missing not at random) and missing rates (10–50%). Across scenarios, SG-MoE consistently matches or improves upon the baseline; the largest gains occur under MCAR and the challenging MNAR setting, where spatial specialization reduces systematic underestimation of high crack-rate sections. The results provide practical guidance on when spatially aware ensembling is most beneficial for infrastructure imputation at scale. We additionally report comparative results under three missingness mechanisms. Across five random seeds, SG-MoE is comparable to the single LightGBM baseline under MCAR/MAR and achieves its largest gains under MNAR (e.g., sMAPE improves by 0.82 points at 10% MNAR missingness).

31 December 2025

Adaptive traffic signal control is a critical component of intelligent transportation systems, and multi-agent deep reinforcement learning (MARL) has attracted increasing interest due to its scalability and control efficiency. However, existing methods have two major drawbacks: (i) they are largely driven by current and historical traffic states, without explicit forecasting of upcoming traffic conditions, and (ii) their coordination mechanisms are often weak, making it difficult to model complex spatial dependencies in large-scale road networks and thereby limiting the benefits of coordinated control. To address these issues, we propose TG-MADDPG, which integrates short-term traffic prediction with a graph attention network (GAT) for regional signal control. A WT-GWO-CNN-LSTM traffic forecasting module predicts near-future states and injects them into the MARL framework to support anticipatory decision-making. Meanwhile, the GAT dynamically encodes road-network topology and adaptively captures inter-intersection spatial correlations. In addition, we design a reward based on normalized pressure difference to guide cooperative optimization of signal timing. Experiments on the SUMO simulator across synthetic and real-world networks under both off-peak and peak demands show that TG-MADDPG consistently achieves lower average waiting times, shorter queue lengths, and higher cumulative rewards than IQL, MADDPG, and GMADDPG, demonstrating strong effectiveness and generalization.

31 December 2025

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Theoretical Issues on Systems Science
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Theoretical Issues on Systems Science

Editors: Gianfranco Minati, Alessandro Giuliani, Andrea Roli
Decision Making and Policy Analysis in Transportation Planning
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Decision Making and Policy Analysis in Transportation Planning

Editors: Mahyar Amirgholy, Jidong J. Yang

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Systems - ISSN 2079-8954