课程文献中心 更多>>

关键词： CANDU机组   电机   故障   设备管理  

摘要： 本文主要分为4个部分,第一部分简单介绍了CANDU机组电机设备的基本概况,并介绍了设备预维策略,主要包括电机定期润滑、年度检查及解体检修等检修项目;第二部分统计两台机组缺陷种类及数量情况;第三部分介绍了两台机组缺陷主要原因及处理方式,并重点介绍了重要负荷电机缺陷处理情况;最后,总结了两台机组电机维护中存在的不足,及后续跟踪建议。通过以上介绍,对电机设备维护情况进行了大概了解,并对国内同行机组电机类设备管理工作起到参考与借鉴作用。

关键词： 经营特点   材料设备管理   路桥施工   岗位责任制   机械设备  

摘要： 路桥施工项目的不断增加,为路桥施工企业带来了更大的发展机遇。为保证企业自身实力以及竞争优势,企业纷纷加大了对材料设备管理工作的重视力度。通过对路桥施工经营特点的分析,对路桥施工企业材料设备管理举措展开深入性探讨,旨在提高企业材料设备管理水平,保证工程项目施工效率以及施工成本。

关键词： 建筑工程   施工项目   机械设备   管理   思路  

摘要： 机械设备是建筑工程项目开展过程中不可缺少的设备,在具体项目实施阶段做好机械设备的管理控制,有利于提高项目工程的质量。基于此本轮切合实际,在论述建筑工程施工项目机械设备管理现状的基础上,对提高工程机械设备管理的有效措施进行了深入研究,希望论述之后,可以给该领域的工作人员提供一些参考,以不断促进我国项目工程事业的发展。

关键词： PDCA管理   超声诊断设备   质量控制体系   管理质量  

摘要： 目的:构建基于PDCA管理理念的超声诊断设备质量控制体系,以提高超声诊断设备的服务质量。方法:医院超声科于2019年10月构建超声诊断设备质量控制体系,并基于PDCA管理理念优化管理,2019年4~9月为实施前,2019年10月~2020年3月为实施后,比较实施前后超声诊断设备的管理质量及医患双方满意度。结果:实施后超声诊断设备的设备运行管理、安全质量控制、设备定期维修管理等评分,均显著高于实施前(P<0.05)。实施后超声科诊断设备管理缺陷事件发生率,显著低于实施前(P<0.05)。实施后医务人员和患者的满意度,均显著高于实施前(P<0.05)。结论:基于PDCA管理构建超声诊断设备质量控制体系,能够有效提高设备的管理水平。

关键词： 口腔科医疗设备   管理   口腔综合治疗机   日常维护  

摘要： 随着经济的高速发展、生活水平的不断提升,近年来人们对口腔健康问题的重视程度显著提高。医疗设备作为口腔科诊疗服务开展的重要支柱,对其实施科学管理能够更好地延长设备的使用寿命,保障口腔疾病的临床诊治效果。该文立足于口腔科医疗设备管理现状,基于医院开源节流的现代办医理念,提出科学管理口腔科医疗设备的对策,同时以口腔综合治疗机为例,浅述该设备的日常维护方法。

摘要： The Indian Institute of Tropical Meteorology (IITM) has generated seasonal and extended range hindcast products for 1981-2008 and 2003-2016, respectively, using the IITM-Climate Forecast System (IITM-CFS) coupled model at various resolutions and configurations. Notably, our observational analysis suggests that for the 1981-2008 period, the tropical Indo-Pacific drivers, namely, the canonical El Nino-Southern Oscillation (ENSO), ENSO Modoki, and Indian Ocean Dipole (IOD). are significantly associated with the observed Kharif rice production (KRP) of various rice-growing Indian states. In this paper, using the available hindcasts, we evaluate whether these state-of-the-art retrospective forecasts capture the relationship of the KRP of multiple states with the local rainfall as well as the tropical Indo-Pacific drivers, namely, the canonical ENSO, ENSO Modoki, and the IOD. Using techniques of anomaly correlation, partial correlation, and pattern correlation, we surmise that the IITM-CFS successfully simulate the observed association of the tropical Indo-Pacific drivers with the local rainfall of many states during the summer monsoon. Significantly, the observed relationship of the local KRP with various climate drivers is predicted well for several Indian states such as United Andhra Pradesh, Karnataka, Odisha, and Bihar. The basis seems to be the model's ability to capture the teleconnections from the tropical Indo-Pacific drivers such as the IOD, canonical and Modoki ENSOs to the local climate, and consequently, the Kharif rice production.

关键词： Decision-making   Problem-solving   Cognitive task analysis   Cognitive work analysis   Driver behaviour   Railway   Work domain analysis   PEDESTRIAN BEHAVIOR  

摘要： The objective of this paper is to cast users of railway level crossings as flexible and adaptive decision-makers, and to apply a cognitive systems engineering approach to discover new behaviour-based insights for improving safety. Collisions between trains and road vehicles at railway level crossings/grade crossings remain a global issue. It is still far from apparent why drivers undertake some of the behaviours that lead to collisions, and there remains considerable justification for continuing to explore this issue with novel methods and approaches. In this study, 220 level crossing encounters by 22 car drivers were subject to analysis. Concurrent verbal protocols provided by drivers as they drove an instrumented vehicle around a pre-defined route were subject to content analysis and mapped onto Rasmussen's ion Decomposition Space. Three key results emerged. First, when they realise they are in a crossing environment, drivers' natural tendencies are to look for trains (even if not required), slow down (again, even if not required), and for their behaviour to be shaped by a wide variety of constraints and affordances (some, but not all, put there for that purpose by railway authorities). The second result is that expert decision-making in these situations does not describe a trajectory from high-level system purposes to low-level physical objects. Instead, drivers remain at intermediate and lower levels of system abstraction, with many loops and iterations. The final finding is that current level crossing systems are inadvertently constraining some desirable behaviours, affording undesirable ones, and that unexpected system elements are driving behaviour in ways not previously considered. Railway level crossings need to be designed to reveal their functional purpose much more effectively than at present.

关键词： Distributed file system   Cache policy   Submodular optimization   Distributed system   ALGORITHMS   KNAPSACK   STORAGE  

摘要： Nowadays, as the memory capacity of servers become larger and larger, distributed in-memory file systems, which enable applications to interact with data at fast speed, have been widely used. However, the existing distributed in-memory file systems still face the problem of low data access performance in small data reading, which seriously reduce their usefulness in many important big data scenarios. In this paper, we analyze the factors that affect the performance of reading in-memory files and propose a two-layer user space cache management mechanism: in the first layer, we cache data packet references to reduce frequent page fault interruptions (packet-level cache); in the second layer, we cache and manage small file data units to avoid redundant inter-process communications (object-level cache). We further design a fine-grained caching model based on the submodular function optimization theory, for efficiently managing the variable-length cache units with partially overlapping fragments on the client side. Experimental results on synthetic and real-world workloads show that compared with the existing cutting-edge systems, the first level cache can double the reading performance on average, and the second level cache can improve random reading performance by more than 4 times. Our caching strategies also outperform the cutting-edge cache algorithms over 20% on hit ratio. Furthermore, the proposed client-side caching framework idea has been adopted by the Alluxio open source community, which shows the practical benefits of this work.

关键词： Material productivity   Regional productivity   Domestic material consumption   European regions   Economic structures   RESEARCH-AND-DEVELOPMENT   MATERIAL FLOWS   SUSTAINABLE DEVELOPMENT   RESOURCE PRODUCTIVITY   GROWTH   PATTERNS   VARIETY   IMPACT   CHINA   UNION  

摘要： This paper provides an empirical investigation on the effects that regional economic structures exert on the socioeconomic determinants of material productivity. To this aim, first we develop a taxonomy of economic structures for more than 280 European regions that are classified in four overarching groups: agriculture-, in-dustry-, intermediate-and service-based economies. Second, we perform a panel analysis to explore the impact of economic structures on the relationship between socioeconomic drivers and material productivity, during the period 2006?2015. Our results validate the basic hypothesis of the paper, i.e. the structural relationship between material productivity and its driving factors varies according to the underlying economic structures of the re-gions. In particular, we found that: (1) an increase in affluence leads to greater material productivity gains in material-intensive regions rather than in areas with service-oriented economies; (2) the degree of urban agglomeration seems to be the most important driver for material productivity, and its leverage effect is bigger among already densely populated regions. Our findings suggest that the influence of socioeconomic factors on material productivity behaves differently according to the idiosyncratic features that regions exhibit. Such di-versity translates into different needs and opportunities that local policies should address by adopting a place -based perspective.

关键词： Truck   Naturalistic driving studies   Safety-critical events   Crashes   Injuries   Fatalities   CROSS-VALIDATION   BEHAVIOR   RISK  

摘要： The past decade has witnessed continuous growth of naturalistic driving studies (NDSs). When analysing NDS data, safety-critical events (SCEs) are commonly used as surrogates for safety, since actual crashes are very rare. However, the association between SCEs and crashes is not consistent in previous studies and has not been verified among commercial truck drivers. Based on routinely collected kinematic data from 31,828 truck drivers in a large commercial trucking company, this paper examines the association between four types of SCEs (headway, hard brake, collision mitigation, and rolling stability) and crashes, as well as injuries and fatalities. Compared to existing studies on the subject, that are based on up to about 2 million miles driven, our study involves an estimated 2.3 billion miles driven. Bayesian negative binomial models were applied to examine the association between three outcomes (crashes, injuries, and fatalities) and the four SCEs. It was found that a unit increase in the number of any type of SCEs per 10,000 miles was associated with 8.4% (95% credible interval (CI): 8.0?8.8%) increase in crashes per mile and 8.7% (95% CI: 4.8?13.6%) increase in the number of injuries per mile. The increase was different in different types of SCEs: 3.3% (95% CI: 2.6?4%) for headways, 8.1% (95% CI: 7.5?8.7%) for hard brakes, 50.4% (95% CI: 41.4?60%) for rolling stability, and 22.2% (95% CI: 19.8?24.5%) for collision mitigation. The results are consistent when stratified by different business units and driver types. This study provides statistically strong and robust evidence that SCEs are positively associated with crashes and injuries among commercial truck drivers. NDS and kinematic data routinely collected by trucking companies provide a promising opportunity for future data analytic research.