59 research outputs found

    Improved Brain-Storm Optimizer for Disassembly Line Balancing Problems Considering Hazardous Components and Task Switching Time

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    Disassembling discarded electrical products plays a crucial role in product recycling, contributing to resource conservation and environmental protection. While disassembly lines are progressively transitioning to automation, manual or human–robot collaborative approaches still involve numerous workers dealing with hazardous disassembly tasks. In such scenarios, achieving a balance between low risk and high revenue becomes pivotal in decision making for disassembly line balancing, determining the optimal assignment of tasks to workstations. This paper tackles a new disassembly line balancing problem under the limitations of quantified penalties for hazardous component disassembly and the switching time between adjacent tasks. The objective function is to maximize the overall profit, which is equal to the disassembly revenue minus the total cost. A mixed-integer linear program is formulated to precisely describe and optimally solve the problem. Recognizing its NP-hard nature, a metaheuristic algorithm, inspired by human idea generation and population evolution processes, is devised to achieve near-optimal solutions. The exceptional performance of the proposed algorithm on practical test cases is demonstrated through a comprehensive comparison involving its solutions, exact solutions obtained using CPLEX to solve the proposed mixed-integer linear program, and those of competitive peer algorithms. It significantly outperforms its competitors and thus implies its great potential to be used in practice. As computing power increases, the effectiveness of the proposed methods is expected to increase further

    Factors influencing householder self-evacuation in two Australian bushfires

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    The thesis investigated householder self-evacuation decision-making during bushfires in the Perth and Adelaide Hills in 2014 and 2015. It explored the factors that influenced householders’ decisions to evacuate, identified factors that predict self-evacuation and established the characteristics of self-evacuators. The Protective Action Decision Model (PADM) provided a conceptual framework for the research. Its theoretical and analytical usefulness in an Australian context, was assessed. A mixed methods research strategy was used involving quantitative telephone surveys of 457 bushfire-affected participants and face-to-face interviews of 109 participants in 59 households. The study concluded that environmental and social cues and warnings and householders’ perceptions of the threat, of hazard adjustments and of other stakeholders, influenced self-evacuation decision-making. Protective action perceptions, particularly the effectiveness of evacuating or not evacuating in protecting personal safety or property, were most important in predicting self-evacuation. Receipt of official warnings and the perception of likely impact of the bushfire on property were also important predictors. Undertaking long-run hazard adjustments, although not predictive of self-evacuation, was pivotal in shaping perceptions of the effectiveness of evacuating and remaining in protecting personal safety and property and indirectly influenced evacuation decisions. Seven archetypes that characterised householders’ self-evacuation attitudes and behaviour were identified. These included Threat, and Responsibility Deniers, Dependent, and Considered Evacuators, Community Guided and Experienced Independents all who took different decisional ‘rules of thumb’ and routes toward evacuating or remaining . The PADM needs to be split into two separate models to incorporate the influence of long-run hazard adjustments on protective action decision-making in an Australian bushfire. The findings suggest that future research on those who wait and see during a bushfire should take account of their decisional rules of thumb and that design and targeting of Australian bushfire safety policy should better account for self-evacuator characteristics

    Some constacyclic self-dual codes over the integers modulo 2m

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    AbstractIn this paper, we explore constacyclic self-dual codes over Z2m. We first characterize constacyclic self-dual codes over Zpm of any length. Then we determine the structure of η-constacyclic self-dual codes over Z2t, where η=−1 or −1+2t−1. This structure is used to find some constacyclic self-dual codes over Z2m

    Distribution and influencing factors of soil selenium and iodine in Limushan-Wanling, Qiongzhong area

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    Qiongzhong Limushan-Wanling area is located in the middle of Hainan Island, where has an abundance of selenium-rich and iodine-rich soil resources.The distribution characteristics of Se and I contents were analyzed based on the analysis results of soil samples in the topsoil (0-20 cm), middle-layer-soil(80-100 cm), and deep-soil (180-200 cm) of the study area.The correlation characteristics of Se and I in soil and their relationship with elevation potentially indicate that the input of rainfall to soil Se and I is a key factor leading to the enrichment of Se and I.By analyzing the correlation and change law between the contents of Se, I and the contents of pH, soil organic matter, Al2O3 and Fe2O3 in top, middle and deep layer soil, the enrichment and migration of Se and I in the vertical section of soil in the study area was summarized.These results can provide scientific basis for the efficient use of local high-quality land resources and provide new evidence for the study of soil Se source and migration
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