Search Results (6)

Production rescheduling involves re-optimizing production schedules in response to disruptions that render the initial schedule inefficient or unfeasible. This process requires simultaneous consideration of multiple objectives to develop new schedules that are both efficient and stable. However, existing review papers have paid limited attention to the multi-objective optimization techniques employed in this context. To address this gap, this paper presents a systematic literature review on multi-objective production rescheduling, examining diverse shop-floor environments. Adhering to the PRISMA guidelines, a total of 291 papers were identified. From this pool, studies meeting the inclusion criteria were selected and analyzed to provide a comprehensive overview of the problems tackled, dynamic events managed, objectives considered, and optimization approaches discussed in the literature. This review highlights the primary multi-objective optimization methods used in relation to rescheduling strategies and the dynamic disruptive events studied. Findings reveal a growing interest in this research area, with “a priori” and “a posteriori” optimization methods being the most commonly implemented and a notable rise in the use of the latter. Hybridized algorithms have shown superior performance compared to standalone algorithms by leveraging combined strengths and mitigating individual weaknesses. Additionally, “interactive” and “Pareto pruning” methods, as well as the consideration of human factors in flexible production systems, remain under-explored. Full article

The World Bank has reported that over one billion individuals have a disability, implying that almost fifteen percent of the global inhabitants are susceptible to undergoing levels of discrimination, especially in employment. This issue may prevail on a manufacturing shop floor, whereby a wave of standardisation dominates such as in the design of shop floor workstations. Despite advances made in the literature, people with disabilities are still siloed from manufacturing. Consequently, the aim of this research work was to analyse literature’s current state of the art on the design of workstations for operators with disabilities within the context of Industry 5.0, where sustainability, human-centricity, and resilience are upheld. The study employed a systematic review of 69 publications from Scopus and Google Scholar published between 2013 and 2023, adhering to the updated PRISMA guidelines to identify the major research gaps. The review contributes an understanding of the current academic and industrial limitations such as the absence of social applicability of Industry 4.0 technology, the rift between academic knowhow and industrial implementation, and the lack of alignment with the sustainable development goals (SDGs). Additionally, the review uncovered an absence in work bridging four disciplines together: workstation design, Industry 5.0, sustainability, and disability. An unprecedented understanding of the interdependency between all four disciplines within the remit of smart, sustainable, and inclusive manufacturing workstations is contributed. This review proposes directions amidst the four most relevant SDGs—SDGs 8, 9, 10, and 12 to the topic. Full article

With the spread of the Industry 4.0 concept, implementing Artificial Intelligence approaches on the shop floor that allow companies to increase their competitiveness in the market is starting to be prioritized. Due to the complexity of the processes used in the industry, the inclusion of a real-time Quality Prediction methodology avoids a considerable number of costs to companies. This paper exposes the whole process of introducing Artificial Intelligence in plastic injection molding processes in a company in Portugal. All the implementations and methodologies used are presented, from data collection to real-time classification, such as Data Augmentation and Human-in-the-Loop labeling, among others. This approach also allows predicting and alerting with regard to process quality loss. This leads to a reduction in the production of non-compliant parts, which increases productivity and reduces costs and environmental footprint. In order to understand the applicability of this system, it was tested in different injection molding processes (traditional and stretch and blow) and with different materials and products. The results of this document show that, with the approach developed and presented, it was possible to achieve an increase in Overall Equipment Effectiveness (OEE) of up to 12%, a reduction in the process downtime of up to 9% and a significant reduction in the number of non-conforming parts produced. This improvement in key performance indicators proves the potential of this solution. Full article

The digital twin is currently recognized as a key technology allowing the digital representation of a real-world system. In smart manufacturing, the digital twin enables the management and analysis of physical and digital processes, products, and people in order to foster the sustainability of their lifecycles. Although past research addressed this topic, fragmented studies, a lack of a holistic view, and a lack of in-depth knowledge about digital twin concepts and structures are still evident in the domain of the shop floor digital twin. Manufacturing companies need an integrated reference framework that fits the main components of both physical and digital space. On the basis of a systematic literature review, this research aims to investigate the characteristics of the digital twin for shop floor purposes in the context of smart manufacturing. The “hexadimensional shop floor digital twin” (HexaSFDT) is proposed as a comprehensive framework that integrates all the main components and describes their relationships. In this way, manufacturing organizations can rely on an inclusive framework for supporting their journey in understanding the shop floor digital twin from a methodological and technological viewpoint. Furthermore, the research strengthens the reference literature by collecting and integrating relevant contributions in a unique framework. Full article

There is a need for knowledge of how the spatial features of the urban environment can shape the potential for safe streets and a gender inclusive society. This research reveals the relationship between a built environment’s spatial features, the presence of various types of people, and gender-based sexual violence in the public space of four neighborhoods in Rotterdam. Detailed sexual violence data are obtained from the police on a street resolution level for correlation with the spatial data on a micro and macro scale level (the space syntax method) and registrations regarding human behavior on streets at different time periods. Pooled Poisson regression models were created to explain the number of sexual violence reports per street and per block. The result is that there are correlations between the occurrence of sexual crimes, the number of people and women on the streets, local spatial integration, the land use of streets, and temporal aspects. Non-residential streets are safe during the day but become dangerous at night, and mixed land use is safer than mono-functional areas. A high degree of inter-visibility for entrances generates high degree of natural surveillance, resulting in greater safety on streets. A residential street with higher flow of people has fewer incidents than mono-functional commercial blocks. Commercial blocks have higher numbers of incidents at night due to the lack of natural surveillance from windows on the ground floor after shops close. Full article

Feasibility studies have been performed on ingots with reduced hot-top heights for the cost-effective hot forging of heavy ingots. The quality of the heavy ingots is generally affected by internal voids, which have been known to be accompanied by inclusions and segregation. To guarantee the expected mechanical performance of the forged products, these voids should be closed and eliminated during the hot open die forging process. Hence, to effectively control the internal voids, the optimum hot-top height and forging schedules need to be determined. In order to improve the utilization ratio of ingots, the ingot hot-top height needs to be minimized. To investigate the effect of the reduced hot-top height on the forged products, shaft and bar products have been manufactured via hot forging of ingots having various hot-top heights. From the operational results, the present work suggests effective forging processes to produce acceptable shaft and bar products using ingots having reduced hot tops. The mechanical properties of shop-floor products manufactured from ingots with reduced hot tops have also been measured and compared with those of conventional ingot products. Full article