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Fifty years of multi-objective optimization and decision-making : From mathematical programming to evolutionary computation
No full textWe review major developments in multi-objective optimization over the past decades. Although mathematical foundations and basic concepts have been established earlier, substantial progress in methods for constructing and identifying preferred solutions started in the late 1950s. We classify these approaches into two broad categories: mathematical programming-based and population-based. The former originated in the late 1950s, and its growth accelerated from the 1970s onward. We differentiate between approaches dealing with problems that operate in a continuous solution space and combinatorial problems where some variables are restricted to integer values. Population-based approaches flourished in the 1990s. Our focus is on evolutionary computation techniques that either aim to discover the entire Pareto front or incorporate the decision maker's preferences to select the most favorable solution(s) or bias the search toward preferred regions. For all categories, we discuss those approaches that, in our opinion, have made major impacts. We examine current research trends and speculate on future directions in the field
Dynamic response of grain rotation and slipping system activity in Al6014 tailor heat treated blank after non-uniform loading via crystal plasticity finite element method
No full textPlastic instability and premature failure during the forming of tailor heat-treated blank (THTB) can be probably inhibited by the introduction of a non-uniformly distributed pressure (NUDP) field due to the reduction of pressure localization on the heat-treated zone (HTZ). Nevertheless, the inherent complex thermal and mechanical loading conditions of such a process exhibit the underlying challenges in revealing its potential physical mechanisms. In this work, the deformation mechanisms of Al6014 THTB under NUPD are systematically investigated via the crystal plasticity finite element method, aiming to establish the dynamic response between the lattice structure, crystallographic orientation, and slip system activity at the microscopic level and the macroscopic plastic behaviors. The evolution of the slip system normal of the representative grains indicates that as compared to uniformly distributed pressure, NUDP can enhance grain rotation in the as-received zone and HTZ, leading to a higher fraction of grains with rotation angles (ξ) deviating from ξ = 0°. Besides, the evolution of slip system activity and cumulative shear strain rate suggests that when NUDP is introduced, the normal pressure on the HTZ is decreased, leading to the reduced increasing rate of slip system activation in each loading transient and the enhanced probability of simultaneous activation of multiple slip systems. This can promote the multi-directional slip activation within the HTZ, but maintain the limited dislocation movement and propagation rate so that significant grain rotation and intergranular deformation are suppressed. Accordingly, the duration of plastic shear strain accumulation is prolonged, which can mitigate the strain localization in the HTZ and improve the macroscopic forming limit. The new insights into the relationships between the microstructure evolution and mechanical response of Al6014 THTB under complex load conditions may facilitate process control
Operations & Supply Chain Management : Principles and Practice
Get PDFOperations and Supply Chain Management (OSCM) has continually evolved, incorporating a broad array of strategies, frameworks, and technologies to address complex challenges across industries. This encyclopedic article provides a comprehensive overview of contemporary strategies, tools, methods, principles, and best practices that define the field’s cutting-edge advancements. It also explores the diverse environments where OSCM principles have been effectively implemented. The article is meant to be read in a nonlinear fashion. It should be used as a point of reference or first-port-of-call for a diverse pool of readers: academics, researchers, students, and practitioners
Designing play into urban environments : strategic-level challenges and best practice in Bradford and Tower Hamlets, UK
No full textChildren have a fundamental need to play and be physically active for their health and wellbeing. Cities, enacted through both built environment and strategic policies, have the potential to enhance or restrict urban physically active play. But cities have densification pressures, and space and infrastructural support for children’s outdoor play are often a low priority. As part of a project scoping ways to ‘design-in’ physically active play in two urban areas of England, we report on the strategic challenges and opportunities that shape urban children’s outdoor play. Policy analysis and fieldwork capturing the views and experiences of policy stakeholders representing public health, play, greenspaces, inclusion, corporate strategy, and urban design in Tower Hamlets and Bradford demonstrates both the extent of barriers to improving playable spaces and some ways to shift the policy mindset. Recommendations concern the need for effective alignment and coordination across policy areas; to establish cross-departmental collaboration; the development of a robust local evidence base; and the importance of ambitious and motivated stakeholders
Numerical study on waste heat recovery characteristics of non-Newtonian thermally hydrolyzed sewage sludge using dimpled tubes
Get PDFFollowing high-temperature thermal hydrolysis treatment, the sewage sludge contains substantial quantities of recoverable waste heat. Enhancing the waste heat recovery efficiency from this thermally hydrolyzed sludge can significantly reduce the operational costs of wastewater treatment plants. This study investigates the performance and entropy generation characteristics of waste heat recovery from thermally hydrolyzed sewage sludge with non-Newtonian fluid properties using dimpled tubes through numerical simulations. The experimental results demonstrate that dimpled tubes exhibit superior waste heat recovery efficiency compared to smooth tubes. Overall, the ellipsoidal dimpled tubes exhibit superior Performance Evaluation Criteria (PEC) values compared to spherical configurations, whereas spherical dimpled tubes demonstrate better entropy production performance. Specifically, under the same geometric parameters, the Nusselt number (Nu) and friction factor (f) of ellipsoidal dimpled tubes are 1.63–1.92 times and 2.65–3.32 times of smooth tubes, respectively, with a maximum PEC value of 1.39. Under the same geometric parameters compared to smooth tubes, the entropy generation is reduced by up to 50 % for spherical dimpled tubes. Furthermore, the results indicate that the relative influence of dimple geometric parameters on various performances exhibits a hierarchy of depth > number > pitch. These results provide valuable insights into the complex interplay between geometric parameters and non-Newtonian fluid flow characteristics
Six‐Component Electromagnetic Wave Measurements of Sprite‐Associated Lightning
Get PDFPlain Language Summary: Sprites are Transient Luminous Events above thunderclouds that tend to occur after intense lightning activity. The lightning emits electromagnetic waves that can be recorded hundreds of kilometres away. The electromagnetic waves are composed out of six different components. Here we report for the first time the simultaneous measurement of all six components. It is found that all the six components are well related to each other with very high precision. For the deployment of arrays with a large number of measurement instruments, it is therefore possible to choose horizontal electric field measurements which are cost‐effective and logistically convenient, in particular in harsh environments. At the same time, such array experiments can be used as a pathfinder mission for the planned deployment of an astronomical array on the far side of the moon to detect celestial objects which cannot be measured at the surface of the Earth
Book review: Corporate Restructuring Law in Flux, edited by Jennifer Payne and Kristin van Zwieten
Get PDFTask modulation of visual category selectivity at physical and conceptual levels : An ERP study
No full textVisual perception emerges from dynamic interactions between bottom‑up sensory input and top‑down, task‑driven expectations. This study tested whether task‑related ERP modulations during object categorization depend on low‑level category‑specific features—specifically the amplitude spectrum (AS)—or whether they arise independent of these features. Participants viewed grayscale images of animals and vehicles with either intact or equalized AS, each paired with an “X” or “O.” They performed either a category‑relevant task (animal vs. vehicle) or a category‑irrelevant task (“X” vs. “O”). Task demands influenced visual processing at multiple stages. P1 category selectivity emerged only for intact AS stimuli under category-relevant task demands, indicating sensitivity to low-level structure. In contrast, P2/N2 differences were present across AS and task conditions, although their magnitude was modulated, consistent with higher-level category representations. The lack of sustained early effects raises questions about how sensory evidence is transformed across processing stages. Manipulating category relevance revealed task modulation beyond response-format effects, showing how top-down goals shape both early sensory and later category-level processing as reflected in distinct visual ERP components
Age of Correct Sensing in Sensing-and-Then-Transmit ISAC Networks
Get PDFThis paper investigates the sensing-and-then-transmit (SAT) integrated sensing and communication (ISAC) network, where a multi-functional base station (MBS) senses the target's state and then transmits the sensed results to the receiving node (RN). To measure the timeliness of the SAT process, we define a novel metric called Age of Correct Sensing (AoCS). To enhance the system's AoCS, we propose a pipelined SAT ISAC (P-SAT ISAC) paradigm, where the MBS simultaneously transmits individual beams to perform sensing and communication. We derive the mathematical expression of the probability of detection (PD), the probability of false alarm (PFA), and the probability of communication outage (PCO), based on which, the AoCS of the P-SAT ISAC is quantified. Furthermore, we formulate an expected AoCS minimization problem by optimizing the power splitting factor for sensing and communication to explore the achievable lower bound of AoCS. Then, the minimum expected AoCS is found by developing a linear search based algorithm. Simulation results validate the theoretical analysis on PD, PFA, and PCO, and also show the impact of system parameters on them, as well as the minimum achievable expected AoCS. Compared with the existing alternating SAT ISAC (A-SAT ISAC), our proposed P-SAT ISAC achieves an average reduction in expected AoCS of 38.97%, demonstrating the efficiency of the proposed pipelined sensing and communication paradigm in improving system timeliness
Visioning to support early-stage sustainable servitization
Get PDFServitization - the process by which manufacturers integrate services into their product offerings - presents significant opportunities to advance sustainability objectives for both producers and customers. However, the early-stage visioning process, during which initial ideas for future service offerings are developed, still remains underexplored. This gap is critical, as an unclear early vision can undermine the servitization efforts and limit their sustainability impact. This paper presents the case of a multinational machine manufacturer developing a sustainability-oriented servitization strategy to explore the central question: How can early-stage visioning for sustainability-driven servitization be practically facilitated? Employing a single case study methodology, the research follows a four-step process grounded in sensemaking theory to examine how manufacturers can identify and shape environmentally focused service offerings. The four steps include:(1)opportunity mapping, which identifies potential service-based sustainability initiatives; (2) value proposition design, where these opportunities are transformed into a coherent service vision;(3) an outside-in perspective, incorporating insights from peer manufacturers to build ambition and confidence; and (4) force-field analysis, used to translate the emerging vision into an actionable implementation plan.Data were collected through interviews and workshop observations and examined using a thematic analysis process. Our findings highlight key challenges manufacturers face during early-stage visioning, including limited customer insights, a lack of shared vocabulary, and uncertainty about market viability. We also show how targeted interventions can overcome these challenges, thereby advancing opportunities for driving sustainable innovation.The findings contribute to servitization theory by examining early-stage visioning, particularly in the context of sustainability. They also extend the application of sensemaking theory, not just as a lens for interpretation but as a structured guide for research and action. The study further demonstrates how targeted interventions can help overcome common barriers, facilitating sustainable innovation through servitization