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Constraint decision-making systems in engineering
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BOOK
Advances and challenges in P2P energy trading: A review of renewable integration and decarbonisation in Ireland
Peer-to-peer (P2P) energy trading has emerged as a promising model for decentralised energy markets, allowing consumers to trade electricity directly. This paper explores the advances and challenges in P2P energy trading, with a historical review of its global development and a particular focus on Ireland. Despite technical advancements, several constraints hinder widespread adoption. Ireland lacks a clear legal framework to support P2P energy trading, creating regulatory uncertainty. Additionally, user acceptance remains low due to limited awareness, trust issues, and the complexities associated with participation. These challenges, combined with grid constraints and pricing uncertainties, have slowed progress. This paper shows that while P2P energy trading offers a decentralised, consumer-driven alternative to traditional energy markets, its success in Ireland will depend on regulatory evolution, technological diversification, and increased consumer engagement.
Journal Article
The impact of public procurement on financial barriers to general and green innovation
This study investigates whether public procurement mitigates or exacerbates innovative enterprises’ financial constraints. We distinguish between general and environmentally beneficial innovative enterprises. Theory suggests that the treatment effects of public procurement, particularly when mediated by the demand-pull effect, may lower a company’s funding constraints for innovation. We test this theory with extended probit models allowing for endogenous treatment and selection. The findings reveal a significantly positive treatment effect of public procurement on the probability of facing financial constraints in both areas: general and environmentally beneficial innovative activities. Thus, the principal implications of this study are (1) that being an innovating SME exacerbates financial constraints and (2) that strengthening SMEs’ participation in European public tenders would not contribute to lowering SMEs’ financial constraints. On the contrary, complementary grants or other financial incentives might be necessary to substantially increase the SMEs’ bidding rates in public tenders.Plain English SummaryPublic procurement incre ases the chance of innovative firms, in particular SMEs, to face financial constraints. This study investigates whether public procurement mitigates or exacerbates financial constraints of enterprises with general or environmentally beneficial innovative activities. The principal implication is that owning a public procurement contract is no instrument to lower innovative firms’, in particular SMEs’, financial constraints. On the contrary, complementary grants or other financial incentives might be necessary to substantially increase the SMEs’ bidding rates in a public tender.
Journal Article
An adaptive NHC-assisted GNSS/INS integrated positioning method
Accurate positioning is essential for train operational efficiency and automation. Although GNSS/INS/Non-Holonomic Constraints (NHC) integration provides continuous navigation, enforcing NHC during train side-slip, vibration, or track irregularities introduces significant positioning errors. To resolve this, we propose an adaptive NHC-assisted GNSS/INS integrated positioning method. First, an EKF tightly couples GNSS and INS measurements. Crucially, we design an NHC validity detector that constructs a test statistic from NHC observation residuals. This statistic is continuously compared against a detection threshold: NHC constraints are selectively activated only when residuals indicate validity; otherwise, they are automatically disabled to prevent error contamination. Field tests on railway lines demonstrate that the adaptive strategy: reduces lateral positioning RMS error by 11.4% compared to forced-NHC approaches.
Journal Article
An integrated scheduling genetic algorithm based on process constraint matrix and family definition coding
To address the complex product-integrated scheduling problem, an improved genetic algorithm based on process constraint matrix and family definition is proposed. The algorithm features a coding method that accurately represents the processing sequence constraints in the product process tree and introduces a simplified method for defining families and sub-processes. On this basis, a hierarchical relationship matrix is derived from the constraint matrix. To resolve the issue of infeasible solutions arising from crossover and mutation operations, a family-based single-parent genetic improvement algorithm is designed. Experimental results validate the effectiveness of the proposed algorithm.
Journal Article
Learning to select SAT encodings for pseudo-Boolean and linear integer constraints
Many constraint satisfaction and optimisation problems can be solved effectively by encoding them as instances of the Boolean Satisfiability problem (SAT). However, even the simplest types of constraints have many encodings in the literature with widely varying performance, and the problem of selecting suitable encodings for a given problem instance is not trivial. We explore the problem of selecting encodings for pseudo-Boolean and linear constraints using a supervised machine learning approach. We show that it is possible to select encodings effectively using a standard set of features for constraint problems; however we obtain better performance with a new set of features specifically designed for the pseudo-Boolean and linear constraints. In fact, we achieve good results when selecting encodings for unseen problem classes. Our results compare favourably to AutoFolio when using the same feature set. We discuss the relative importance of instance features to the task of selecting the best encodings, and compare several variations of the machine learning method.
Journal Article
Assessing Hierarchical Leisure Constraints Theory after Two Decades
This article assesses the status of hierarchical leisure constraints theory (Crawford & Godbey, 1987; Crawford, Jackson, & Godbey, 1991) regarding many issues. Such issues include clarification and elaboration of some aspects of the original model, a review of studies which have used or examined the model and the extent to which they are confirmatory, critiques of the original model by various authors, and avenues for further research. Conclusions drawn include that the model is cross culturally relevant, that the model may examine forms of behavior other than leisure, and that, while research to date has been largely confirmatory, there is a high potential for the theory to be expanded in order to advance leisure constraints research to the next level.
Journal Article
A single-objective optimization model for power systems with the introduction of line-heavy load rate index constraints
The increasing penetration of new energy sources in new power systems has exacerbated the volatility and complexity of power system currents. Grid planning is facing higher challenges. Established grid planning models usually use the upper and lower limits of grid transmission capacity as constraints, but this may lead to long-term heavy load operation of certain lines and increase system risks. Therefore, this paper designs a line-heavy load rate constraint and establishes a single-objective optimization model for grid planning based on this constraint. Example analyses verify the effectiveness of adding line-heavy load rate constraints in planning and the reasonableness of the single-objective optimization model.
Journal Article
On the Relatedness and Nestedness of Constraints
The purpose of this opinion paper is providing a platform for explaining and discussing the relatedness and nestedness of constraints on the basis of four claims: (a) task constraints are distributed between the person and the environment and hence are relational variables, (b) being relational, task constraints are also emergent properties of the organism/environment system, (c) constraints are nested in timescales, and (d) a vast set of constraints are correlated through circular causality. Theoretical implications for improving the understanding of the constraints-led approach and practical applications for enhancing the manipulation of constraints in learning and training settings are proposed.
Journal Article
Numerical Solution of an Optimal Control Problem with Probabilistic and Almost Sure State Constraints
We consider the optimal control of a PDE with random source term subject to probabilistic or almost sure state constraints. In the main theoretical result, we provide an exact formula for the Clarke subdifferential of the probability function without a restrictive assumption made in an earlier paper. The focus of the paper is on numerical solution algorithms. As for probabilistic constraints, we apply the method of spherical radial decomposition. Almost sure constraints are dealt with a Moreau–Yosida smoothing of the constraint function accompanied by Monte Carlo sampling of the given distribution or its support or even just the boundary of its support. Moreover, one can understand the almost sure constraint as a probabilistic constraint with safety level one which offers yet another perspective. Finally, robust optimization can be applied efficiently when the support is sufficiently simple. A comparative study of these five different methodologies is carried out and illustrated.
Journal Article