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481.
针对国内小型航空公司生产运行中的单基地线性航线结构特点,首次把飞行员疲劳问题与机组排班问题相结合,以周航班计划为基础,对传统机组排班指派模型进一步改进创新,研究基于疲劳度均衡的飞行机组排班指派模型。一是对机组飞行疲劳进行量化,确定飞行员疲劳程度计算模型;二是构建基于疲劳度均衡的机组排班指派模型;三是采取遗传算法求解;四是以现有航空公司的航班计划进行实例研究,并与原排班中当天飞行员的疲劳程度进行比较分析。结果证明,飞行员的疲劳程度得到了大量改善,且每名飞行员的疲劳程度与当天疲劳度均值的差异较小,飞行员的疲劳程度较稳定,故基于疲劳度均衡的机组指派模型研究是真实且有效的。 相似文献
482.
《Socio》2023
During the preparation before a hurricane makes landfall, affected individuals may be asked to evacuate. Large and small-scale evacuations can cause rapid increases in the demand for gasoline fuel. However, during a hurricane vessels carrying gas may be delayed and/or rerouted, adding to the difficulty of providing the necessary gas in affected areas. In this work, we determine alternate delivery locations and times for vessels carrying fuel that are scheduled to arrive and deliver fuel at ports impacted by an approaching hurricane. Motivated by Hurricane Irma in Florida, we develop a multi-period stochastic scheduling model that incorporates hurricane (weather) advisories, fuel delivery schedules, port storage capacities, and port docking capacities. Our model determines the best schedule based on two objectives: (1) minimize the total unmet demand at each port, and (2) minimize inequities in unmet demands among the ports. We also present a case study and a numerical experiment based on fuel delivery data from ports in Florida. Among our key findings is that port availability is the driving factor in determining feasible schedules for vessel gas deliveries. We also present a scheduling heuristic that dynamically adapts to weather advisories so as to minimize the impact of unmet demand in the affected areas. 相似文献
483.
484.
利用2006—2019年中国 30 个省区市的相关数据对区域经济发展水平系统和吸引外资能力系统进行综合评价,通过耦合协调度和 PVAR模型实证分析两系统间的耦合与互动发展特征。研究发现:2006—2019年经济发展水平和吸引外资能力均有明显改善,各省区市的系统耦合协调度为 0.11—0.61,呈平稳上升的态势;在空间上,耦合协调度的局部莫兰散点主要分布在一、三象限,说明大部分地区呈现“高?高”或“低?低”聚集的空间特征;在互动关系上,吸引外资能力受到区域经济发展水平的影响程度较大,而区域经济发展水平受到吸引外资能力的影响程度则相对较小。 相似文献
485.
In this paper, we propose a new explicit series expansion formula for the price of an arithmetic Asian option under the Black–Scholes model and Merton's jump-diffusion model. The method is based on an equivalence in law relation together with the diffusion operator integral method proposed by Heath and Platen. The method yields explicit series expansion formula for the Asian options' prices. The theoretical convergence of the expansion to the true value is established. We also consider the American Asian option (i.e., Amerasian option) and derive the corresponding expansion formula through the early exercise premium representation. Numerical results illustrate the accuracy and efficiency of the method as compared with benchmarks in the literature. 相似文献
486.
目的探讨自拟中药方剂养胃汤加减治疗慢性萎缩性胃炎患者的疗效。方法选取2018年11月至2019年11月营口市中医院收治的100例慢性萎缩性胃炎患者作为研究对象,随机分为胃复春片组与联合用药组,各50例。胃复春片组给予胃复春片,联合用药组在对照组治疗基础上采用自拟中药方剂养胃汤加减治疗,比较两组中医证候积分,炎症介质及胃泌素-17(G-17)、胃蛋白酶原Ⅰ(PGⅠ)、胃蛋白酶原Ⅱ(PGⅡ)水平,一氧化氮(NO)、超氧化物歧化酶(SOD)、丙二醛(MDA)水平及不良反应。结果治疗后联合用药组胃刺痛、胃脘胀满、食少纳呆、消瘦及乏力积分低于胃复春片组(P<0.05);治疗后,联合用药组CRP、TNF-α及IL-6水平低于胃复春片组(P<0.05),G-17、PGⅠ、PGⅡ高于胃复春片组(P<0.05);治疗后,联合用药组NO、SOD水平高于胃复春片组(P<0.05),MDA水平低于胃复春片组(P<0.05);两组不良反应发生率比较,差异无统计学意义(P>0.05)。结论自拟中药方剂养胃汤加减治疗慢性萎缩性胃炎能有效缓解患者症状,减轻机体炎症反应,未增加不良反应发生率。 相似文献
487.
488.
《Socio》2023
The demand for home care (HC) services has steadily been growing for two main types of services: healthcare and social care. If, for the former, caregivers' skills are of utter importance, in the latter caregivers are not distinguishable in terms of skills. This work focuses social care and models caregivers' synchronization as a means of improving human resources management. Moreover, in social care services, several visits need to be performed in the same day since patients are frequently alone and need assistance throughout the day. Depending on the patient's autonomy, some tasks have to be performed by two caregivers (e.g. assist bedridden patients). Therefore, adequate decision support tools are crucial for assisting managers (often social workers) when designing operational plans and to efficiently assign caregivers to tasks. This paper advances the literature by 1) considering teams of one caregiver that can synchronize to perform tasks requiring two caregivers (instead of having teams of two caregivers), 2) simultaneously modelling daily continuity of care and teams' synchronization, and 3) associating dynamic time windows to teams' synchronizations introducing scheduling flexibility while minimize service and travel times. These concepts are embedded into a daily routing and scheduling MIP model, deciding on the number of caregivers and on the number and type of teams to serve all patient tasks. The main HC features of the problem, synchronization and continuity of care, are evaluated by comparing the proposed planning with the current situation of a home social care service provider in Portugal. The results show that synchronization is the feature that most increases efficiency with respect to the current situation. It evidences a surplus in working time capacity by proposing plans where all requests can be served with a smaller number of caregivers. Consequently, new patients from long waiting lists can now be served by the “available” caregivers. 相似文献
489.
490.
《Socio》2023
With the increase in renewable energy generation and its problems related to output instability, storage systems must be implemented in parallel to account for this effect. Therefore, it is valuable to deepen the study of these technologies’ performances in their several application tiers, thus understanding the potential of each alternative, both per tier and as a whole. For this reason, a collaborative multi-criteria decision-aiding framework is proposed to rank the various available options in several layers of the energy storage market, constructed alongside experts and policy-makers from each tier that serve as actors of the decision-making process and using Portugal as a case study. Based on the Choquet multi-criteria preference aggregation model, to the best of the authors’ knowledge, this framework is an unprecedented application in the energy sector. Beyond a critical review of the results, a scenario analysis was performed to explore interesting future possibilities that may aid governments to make decisions in the search for an energy sustainable development. Chemical storage solutions, such as Hydrogen and Methane, as well as several electrochemical batteries, especially Lithium- and Nickel-based ones, were the standout energy storage solutions. Chemical storage was shown to have the desired characteristics for the Long-term grid tier. Meanwhile, batteries, including Redox Flow in the first case, have overperformed in the Microgrid and Mobility tiers. No standout solutions appeared in the Short-term grid tier. Unsurprisingly, the aforementioned chemical storage systems, batteries, and Hot Water have presented themselves as the most politically interesting technologies, due to their multipurpose uses and intrinsic characteristics. 相似文献