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This article takes the geological disasters of avalanches and landslides in the upper mountain of a mine in Guizhou Province as an example, and uses discrete and finite element numerical analysis methods to establish two-dimensional and three-dimensional numerical calculation models of slumped mass. The change process of the stability coefficient of the upper slope of the coal mine under the action of underground excavation is calculated, and the formation mechanism of the collapse body is analyzed from the aspects of displacement, stress and strain of the mountain instability. The research results show that the underground mining activities of coal mines under natural conditions have an impact on the stability of the upper mountain. When the local underground coal mining activities are close to the mountain, the mining activities have little effect on the stability of the mountain. However, when the mining activities are carried out in the lower part of the mountain, its influence on the stability of the mountain gradually increases, which shows that underground mining activities are one of the main factors leading to the occurrence of avalanche disasters in the upper mountain of a mine in Guizhou Province.

This study stems from a furniture factory producing products by cutting and splicing operations. We formulate the problem into an assignment-based model, which reflects the problem accurately, but is intractable, due to a large number of binary variables and severe symmetry in the solution space. To overcome these drawbacks, we reformulate the problem into a clustering-assignment-based model (and its variation), which provides lower (upper) bounds of the assignment-based model. According to the classification of the board types, we categorize the instances into three cases: Narrow Board, Wide Board, and Mixed Board. We prove that the clustering-assignment-based model can obtain the optimal schedule for the original problem in the Narrow Board case. Based on the lower and upper bounds, we develop an iterative heuristic to solve instances in the other two cases. We use industrial data to evaluate the performance of the iterative heuristic. On average, our algorithm can generate high-quality solutions within a minute. Compared with the greedy rounding heuristic, our algorithm has obvious advantages in terms of computational efficiency and stability. From the perspective of the total costs and practical metrics, our method reduces costs by 20.90% and cutting waste by 4.97%, compared with a factory's method. [ABSTRACT FROM AUTHOR]

In the context of anomalous global climate change and the frequent occurrence of droughts and floods, studying trends in the conversion rate between precipitable water vapor (PWV) and actual precipitation in a certain region can help in analyzing the causes of these natural disasters. This paper examines the variation trend in the conversion rate between PWV and actual precipitation on a monthly scale in Hubei from 1960 to 2020. To estimate historical PWV data, we propose a new method for estimating PWV using water vapor pressure based on the RF algorithm. The new method was evaluated by radiosonde data and improved the accuracy by 1 mm over the traditional method in Hubei. Based on this method, we extrapolate the monthly average PWV in Hubei from 1960 to 2020 and analyze the conversion rate between PWV and precipitation during this period. Our results showed that there was no obvious cyclical pattern in the conversion rate in either the longitude or latitude directions. In Hubei, where the topography varies significantly in the longitude direction, the conversion rate is influenced by topography, with the smallest conversion rate being in the transition zone between the mountainous region of western Hubei and the Jianghan Plain. In the latitudinal direction, the conversion rate decreases with increasing latitude. [ABSTRACT FROM AUTHOR]

We study the product design problem where a decision maker selects the features of a product from a set of feasible options. We focus on two widely studied objectives in this field, that is, the share of choice (SOC) and buyers' welfare (BW). The two objectives are vulnerable to different types of customer preference misspecification, that is, deviation from the nominal utility distribution and effects of outliers, respectively. We formulate a distributionally robust optimization (DRO) SOC maximization model and a winsorized BW maximization model to obtain robust solutions to the two problems. Interestingly, we show that the two robust models are equivalent in a certain sense—for appropriate choices of robustness parameters, both models return the same solution. This observation has important ramifications. For instance, it indicates that a product designed to yield higher BW is more robust to the deviation from the nominal utility distribution for the SOC problem, while that with higher SOC is less sensitive to the effect of outliers for the BW problem. Last but not least, we use the equivalence to develop a new approach to solve the DRO model for the SOC problem, using a version of the winsorized BW model. Extensive numerical experiments demonstrate the superior performance of the proposed approach. [ABSTRACT FROM AUTHOR]

Shortening the lead time for Product Development (PD) provides enterprises with a competitive advantage. Given the iterative nature of PD projects, two aspects are regularly considered to shorten the PD lead time, that is, conducting faster or fewer iterations. However, executing faster iterations usually causes more iterations and vice versa. Therefore, suitable coordination between faster and fewer iterations is necessary to minimize the PD lead time. We investigate this coordination from a strategic perspective, whereby a PD project is considered as a sequence of stages and characterized by the design rates and rework probabilities of those stages. We model the coordination as a decision to choose the appropriate design rates for each stage, wherein the rework probabilities are negatively related to the design rates. An absorbing Markov process is applied to calculate the expected lead time of a PD project. Further, we formulate a geometric programming model to determine the optimal design rates of the stages with respect to the minimal expected lead time. Several insights are extracted from the model to provide general guidance on the coordination, including the effect of the acceptance check rate of the project, rework risk of the stages on the optimal design rates, and decomposability of the coordination. Inspired by these insights, an efficient heuristic algorithm is designed. The algorithm performs well in numerical experiments, which in turn validates the insights. Additionally, a field case proves the effectiveness of our model. Compared with the current policy, 12.25% of the PD lead time is saved through appropriate coordination between faster and fewer iterations. [ABSTRACT FROM AUTHOR]

A study was performed on the effects of bilateral eyestalk ablation on signal transduction pathways of ion regulation of Litopenaeus vannamei. The study included three treatments (starvation group, bilateral eyestalk ablation, and starvation and bilateral eyestalk ablation) in addition to a control group. The shrimp were sampled at 0, 12, 24, and 48 h. Results showed that the ablation of bilateral eyestalk had significant effects on the contents of three kinds of biogenic amines (BAs), cyclic guanosine monophosphate (cGMP), and the activities of three kinds of ion-transport enzymes ( P < 0.05). According to these results, bilateral eyestalk ablation had significant effects on the ion signal pathway of L. vannamei. The same changes were observed in 5-hydroxytryptamine (5- HT) contents, Na+-K+- ATPase, and HCO3−- ATPase activities, suggesting that crustacean hyperglycemic hormone ( CHH) regulated the changes in ion-transport enzymes, mediated by BAs and cGMP. The specific pathways may be 5-HT → cGMP → Na+-K+-ATPase, HCO3−-ATPase, and BAs → cGMP → V-ATPase. 5- HT contents, Na+-K+- ATPase, and HCO3−- ATPase activities in the starvation group were ultimately higher than those in the bilateral eyestalk ablation group, while the cyclic adenosine monophosphate (cAMP) contents increased slightly. Study results suggested that under the situation of bilateral eyestalk ablation, the shrimp could also use feed or its metabolites to increase 5- HT or cAMP contents to regulate the Na+-K+-ATPase and HCO3−-ATPase activities in gills. [ABSTRACT FROM AUTHOR]