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1.
《Risk analysis》2018,38(8):1634-1655
The work in the article presents the development of an application guide based on feedback and comments stemming from various railway actors on their practices of SIL allocation to railway safety‐related functions. The initial generic methodology for SIL allocation has been updated to be applied to railway rolling stock safety‐related functions in order to solve the SIL concept application issues. Various actors dealing with railway SIL allocation problems are the intended target of the methodology; its principles will be summarized in this article with a focus on modifications and precisions made in order to establish a practical guide for railway safety authorities. The methodology is based on the flowchart formalism used in CSM (common safety method) European regulation. It starts with the use of quantitative safety requirements, particularly tolerable hazard rates (THR). THR apportioning rules are applied. On the one hand, the rules are related to classical logical combinations of safety‐related functions preventing hazard occurrence. On the other hand, to take into account technical conditions (last safety weak link, functional dependencies, technological complexity, etc.), specific rules implicitly used in existing practices are defined for readjusting some THR values. SIL allocation process based on apportioned and validated THR values is finally illustrated through the example of “emergency brake” subsystems. Some specific SIL allocation rules are also defined and illustrated. 相似文献
2.
Andrian Liem 《International Journal of Social Research Methodology》2018,21(4):513-525
Sequential explanatory mixed method design is the most frequently applied in both health and social sciences literature. It is denoted by ‘QUAN → qual’ which represents the quantitative study occurs first and has greater weight in addressing the study’s aims, and the qualitative study follows to explain quantitative results. Despite the extensive use of sequential explanatory design, there are limited references to this design. Therefore, this methodological paper attempts to fill the gap by providing an illustration in developing a sequential explanatory interview schedule based on complementary-alternative medicine (CAM) study among clinical psychologists in Indonesia. The most important step to develop sequential explanatory interview schedule was the construction of aspects and questions that were immensely grounded on the most notable quantitative results. In this study, eight aspects of interview schedule were constructed after analyses of the nationwide survey. The interview schedule then piloted among participants with fairly similar characteristics to the participants in the main interviews. This process enhanced the quality of questions through feedback from participants and improved the interviewer’s skills through familiarization with questions. It is expected that this reflection report could be adopted as a practical guideline in developing interview schedule for sequential explanatory mixed method design, particularly in the field of psychology. 相似文献
3.
Michael Palm 《Cultural Studies》2018,32(4):582-599
The internet and other digital networks in the U.S. (and beyond) remain essentially an upgrade of the national telephone network built by AT&T over the first half of the twentieth century, and digital payment remains tethered to telephony at the level of infrastructure. Telephone history also continues to inform digital payment at the level of interface. Debit card readers feature a keypad nearly identical to those introduced (also by AT&T) to the dialling public a half-century ago on touch-tone telephones. In this essay I highlight the development of the touch-tone keypad as a transformative payment technology. There have been three great leaps forward in the history of telephone interface: the dial, the keypad and the touch screen. Each corresponds to a period of technological transformation in the telephone industry and society more broadly: the rotary dial and automation, touch-tone keypads and digitization, and touch screens and computerization. The successful careers of the dial and the keypad, especially when read in tandem, suggest that touch screens will alter the everyday economics of retail payment even more radically than its predecessors. I also describe a broader trajectory of digital naturalization, whereby telephone numbers have proliferated into a personal identification number, passwords and a plethora of personalized information. Payments increasingly circulate today as subsets of personal information within the vast sea of big data. Payment apps are demonstrating a capacity to reorganize retail transactions on a scale as vast as any technology since the cash register. The history of retail payment finds the point of sale heading from the till into shoppers’ pockets. As a result, consumers are increasingly shouldering the costs of purchasing, maintaining, upgrading and securing the technology used for everyday transactions. 相似文献
4.
The exponentially weighted moving average (EWMA) chart is often designed assuming the process parameters are known. In practice, the parameters are rarely known and need to be estimated from Phase I samples. Different Phase I samples are used when practitioners construct their own control chart's limits, which leads to the “Phase I between-practitioners” variability in the in-control average run length (ARL) of control charts. The standard deviation of the ARL (SDARL) is a good alternative to quantify this variability in control charts. Based on the SDARL metric, the performance of the EWMA median chart with estimated parameters is investigated in this paper. Some recommendations are given based on the SDARL metric. The results show that the EWMA median chart requires a much larger amount of Phase I data in order to reduce the variation in the in-control ARL up to a reasonable level. Due to the limitation of the amount of the Phase I data, the suggested EWMA median chart is designed with the bootstrap method which provides a good balance between the in-control and out-of-control ARL values. 相似文献
5.
Andrea Garcia Tapia Mildred Suarez Jose E. Ramirez‐Marquez Kash Barker 《Risk analysis》2019,39(9):2032-2053
Critical infrastructure networks enable social behavior, economic productivity, and the way of life of communities. Disruptions to these cyber–physical–social networks highlight their importance. Recent disruptions caused by natural phenomena, including Hurricanes Harvey and Irma in 2017, have particularly demonstrated the importance of functioning electric power networks. Assessing the economic impact (EI) of electricity outages after a service disruption is a challenging task, particularly when interruption costs vary by the type of electric power use (e.g., residential, commercial, industrial). In contrast with most of the literature, this work proposes an approach to spatially evaluate EIs of disruptions to particular components of the electric power network, thus enabling resilience‐based preparedness planning from economic and community perspectives. Our contribution is a mix‐method approach that combines EI evaluation, component importance analysis, and GIS visualization for decision making. We integrate geographic information systems and an economic evaluation of sporadic electric power outages to provide a tool to assist with prioritizing restoration of power in commercial areas that have the largest impact. By making use of public data describing commercial market value, gross domestic product, and electric area distribution, this article proposes a method to evaluate the EI experienced by commercial districts. A geospatial visualization is presented to observe and compare the areas that are more vulnerable in terms of EI based on the areas covered by each distribution substation. Additionally, a heat map is developed to observe the behavior of disrupted substations to determine the important component exhibiting the highest EI. The proposed resilience analytics approach is applied to analyze outages of substations in the boroughs of New York City. 相似文献
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7.
A smoothed bootstrap method is presented for the purpose of bandwidth selection in nonparametric hazard rate estimation for iid data. In this context, two new bootstrap bandwidth selectors are established based on the exact expression of the bootstrap version of the mean integrated squared error of some approximations of the kernel hazard rate estimator. This is very useful since Monte Carlo approximation is no longer needed for the implementation of the two bootstrap selectors. A simulation study is carried out in order to show the empirical performance of the new bootstrap bandwidths and to compare them with other existing selectors. The methods are illustrated by applying them to a diabetes data set. 相似文献
8.
在田野民族志和历史编纂学中,传记法是一种重要的叙事方式。本文从分析林耀华的作品入手,将其置于20世纪20年代以来的社会学和人类学思想脉络中,并在此基础上探讨传记法在中国历史和社会研究中的潜力与可能性。本文将谱系法、个人生命史和社会生命论归纳为“传记法三角”。在(扩展)谱系法和社会结构论的基础上,生命传记法可以呈现一个或多个人的生命历史,作为大历史中的片段。不过,现象学路径有其自身的限度,不能离开对中央政权本身和总体结构的考察。在“时势”和“社会结构”的变迁过程中呈现生命传记,才不会只是个体的故事,而有希望成为一种对中国“总体”社会生活的有力叙事方式。 相似文献
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10.
随着信息技术的发展,数字经济已经成为经济增长的"新引擎"。但由于缺乏权威的产业统计分类标准,学者们一直面临"数字经济研究缺乏数字依据"的尴尬境地。文章基于国家统计局公布并实施的《数字经济及其核心产业统计分类(2021)》中的分类标准,对各省份统计年鉴的数据进行重新整理,利用熵权法构建数字经济发展指数,测度了我国30个省份的数字经济发展水平,分析了各省份数字经济发展的差异以及时空特征。研究发现,2009—2019年我国数字经济产业发展迅猛,各项子产业都取得了长足的进步。相比较而言,数字要素驱动业发展速度略低于其他三个子产业;数字经济发展存在着明显的区域不平衡。东中部地区的数字经济发展状况明显优于西部地区,南方优于北方,而且区域不平衡有持续扩大趋势。 相似文献