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关键词： 分布式计算机系统  

ISBN: (纸本)9787121428111

摘要： 本书首先介绍什么是分布式系统、分布式系统带来的挑战，以及如何对分布式系统进行建模。接着介绍了分布式数据的基础知识，包括数据分区技术、数据复制技术、CAP定理、一致性模型和隔离级别。本书还介绍了分布式系统的核心算法——Paxos和Raft算法，不仅补充了大量图示进行讲解，还从零实现了一个Paxos算法。此外，本书分析了常见的分布式事务，并讨论了分布式系统中的时间问题，整理了一些实际发生的编程陷阱。最后结合一些对工业界产生重大影响的论文或开源系统，学习前人在设计大型分布式系统时的思路、取舍和创新。

关键词： ride-sharing platform   differential pricing   two-sided markets   price fairness  

摘要： Ride-sharing platforms, such as Uber and Didi Chuxing, widely use differential pricing strategies to encourage platform participation. However, it remains unclear whether differential pricing strategies in ride sharing are reasonable when users care about price fairness. Moreover, platforms face a unique dilemma when considering differential pricing: should it be used for customers, drivers, or both? On the demand side, platforms must deal with taxi competition, while the supply side contends with government regulation;it is this dilemma that motivates our work. Using a stylized model that includes price fairness, market conditions, and government policies, we consider four ride-sharing platform pricing strategies: uniform pricing, differential customer pricing, differential driver pricing, and bilateral differential pricing. We present results from three perspectives. For platforms, we obtain feasible regions in all four pricing strategies. If the maximal number of potential drivers is below certain thresholds, a platform will use differential driver pricing. Conversely, differential customer pricing is optimal when the maximal number of potential drivers is sufficiently large. Moreover, when customers have stronger fairness concerns, platforms tend to use differential driver pricing to reduce competition. From the government perspective, when a platform charges customers differently, the government can achieve a win-win solution for sustainable development and market stability by setting a proper taxi rate. Interestingly, we find that, for the demand and supply sides, an increase in fairness concerns may hurt customers and drivers under certain conditions.

关键词： biological-based measures   driver drowsiness detection   hybrid-based measures   image-based measures   vehicle-based measures  

摘要： Continuous advancements in computing technology and artificial intelligence in the past decade have led to improvements in driver monitoring systems. Numerous experimental studies have collected real driver drowsiness data and applied various artificial intelligence algorithms and feature combinations with the goal of significantly enhancing the performance of these systems in real-time. This paper presents an up-to-date review of the driver drowsiness detection systems implemented over the last decade. The paper illustrates and reviews recent systems using different measures to track and detect drowsiness. Each system falls under one of four possible categories, based on the information used. Each system presented in this paper is associated with a detailed description of the features, classification algorithms, and used datasets. In addition, an evaluation of these systems is presented, in terms of the final classification accuracy, sensitivity, and precision. Furthermore, the paper highlights the recent challenges in the area of driver drowsiness detection, discusses the practicality and reliability of each of the four system types, and presents some of the future trends in the field.

标准号: T/CAPE 10102-2022

标准号: T/CAPE 10103-2022

关键词： 机械设备   维修管理   运作状态  

摘要： 随着科学技术的进步和生产的不断发展,机械设备在企业固定资产中的比重不断增大,企业要想进行生产活动,机械设备是物质技术的基础,也是影响企业产能的重要因素之一,因此,应重视机械设备的维护管理工作.现代机械设备高速化、多功能化、精密化等特点,使得机械设备的成本不断增加,企业应最大限度地降低机械设备的寿命周期费用,提高设备的综合效益,从而提升企业的经济效益.因此,加强企业机械设备的管理工作已经成为企业管理的一项重要任务.企业做好机械设备的修理维护,保证设备优良的运作状态对企业产能的提升、生产的安全运转,以及提高经济效益都有着十分重大的意义.

关键词： 电力机械设备   电力设备管理   机械设备管理  

摘要： 电力机械设备维持着电力企业正常的运营生产,其高效化、无故障的运行是电力生产的基础保障.但是在电力机械设备的管理中,出现了一些问题,由于新设备与新技术的引进,增加了设备数量且提高了技术水平,而管理制度建设滞后,以及相关的管理人员设备知识、技术、素质水平不一,影响到设备管理的成效.所以,电力企业需深入探寻设备管理中存在的问题,针对问题的出处进行管理制度、人员的培养,以及管理力度的强化,以此来全面提升电力机械设备管理的成效,保障自身的生产效能.

关键词： Ecosystem services   Recreation   Social perceptions   Social media   Temporary waterways  

摘要： The undervaluation of the ecosystem services that temporary waterways provide to human wellbeing is one of the most important threats for the conservation and management of these ecosystems. Recreational services might be particularly undervalued in temporary waterways, as there is some evidence that social perceptions and attitudes towards rivers and streams may depend on their flow permanency. The objective of this study was to determine if the recreational use (here considered as an indicator of social perceptions) of temporary wa-terways differs from the recreational use of perennial waterways. We analysed the recreational use of temporary and perennial waterways in a Mediterranean basin using geotagged photographs (with temporal and spatial-coordinate metadata) that were uploaded during the period 2003-2020 on the outdoor recreational website Wikiloc, as well as on Google Earth. The observed recreational activity in each type of waterway was compared with the expected activity, estimated from the proportion of temporary and perennial waterways in the basin, considering the accessibility from both paved and unpaved roads, proximity to populations and flow permanency were significant drivers of recreational activities associated with waterways, thus confirming our two hypotheses of a negative bias towards temporary *** is the first study of our knowledge reporting evidence on the role of flow permanency on the social perception towards waterways. The undervaluation of temporary wa-terways is one of their major threats, and we must activity design and implement management actions to change this social perception from educational activities at schools to restoration actions. (c) 2021 Elsevier B.V. All rights reserved.

关键词： Land degradation   Land degradation neutrality   Driving force   Central Asia  

摘要： Land degradation has become one of the most critical environmental and socioeconomic issues in the world, particularly in Central Asia. Moreover, the realization of Land Degradation Neutrality (LDN) in Central Asia faces enormous challenges in achieving the global Sustainable Development Goal 15.3 (SDG 15.3). It is critical to monitor land degradation and assess its drivers in Central Asia. In this study, an Optimal Land Degradation Index (OLDI) was established as a new index for monitoring land degradation using a constrained optimization algorithm. The spatiotemporal characteristics of LDN were monitored in Central Asia. Further analysis explored the driving force of land degradation in different areas. The results showed that 7.22% and 15.33% of the total land area exhibited land improvement and land degradation, respectively. According to abrupt change analysis, mutation changes in the OLDI were observed in 2005, 2012 and 2015. At the subnational scale, most regions in Central Asia have not achieved the goal of LDN. The residual analysis highlighted the drivers of spatial differences in land degradation performance in Central Asia. Drought was the main driving force affecting land degradation by the compound effect of decreased precipitation and increased temperature on the Ustyurt Plateau, while 24.01% of the land degradation areas resulted from anthropogenic disturbances and were mainly distributed in the areas surrounding the Aral Sea. The results also indicated that 72.56% of the land improvement areas resulted from human activities and were mainly concentrated in the Balkhash Lake Delta and the Amudarya Delta. In Central Asia, the realization of SDG 15.3 by 2030 remains a severe challenge. Restoration measures should be prioritized in land degradation areas in Central Asia to implement the LDN initiative, especially around the Aral Sea. (c) 2021 Elsevier B.V. All rights reserved.