产业智能化与农民工就业质量的影响机理及提升路径

基于当前数字技术快速发展这一现实背景,利用2017-2019年中国家庭金融调查数据,实证检验了产业智能化对农民工就业质量的影响,并从创业、创新和互联网使用三个维度探索就业质量提升路径。研究表明：产业智能化对农民工就业质量具有“替代效应”和“智能化效应”,其中“替代效应”占主导地位,致使产业智能化通过降低农民工的工作稳定性和社会保障水平,阻碍高质量就业;异质性分析发现,第一代和外地农民工、社会资本和技能水平较低的农民工、从事常规性特征工作的农民工、处于东部以及劳动力保护较弱地区的农民工,其就业质量受产业智能化的负向影响更明显。提出促进创业、培养创新意识和提升互联网使用技能可以推进农民工把握新就业形态,从而缓解产业智能化对农民工就业质量的抑制作用、助力高质量就业。     

Consistency of maximum likelihood estimators in a large class of deconvolution models

We consider the maximum likelihood estimator $\hat{F}_n$ of a distribution function in a class of deconvolution models where the known density of the noise variable is of bounded variation. This class of noise densities contains in particular bounded, decreasing densities. The estimator $\hat{F}_n$ is defined, characterized in terms of Fenchel optimality conditions and computed. Under appropriate conditions, various consistency results for $\hat{F}_n$ are derived, including uniform strong consistency. The Canadian Journal of Statistics 41: 98–110; 2013 © 2012 Statistical Society of Canada     

Tail-Adaptive Location Rank Test for the Generalized Secant Hyperbolic Distribution

The generalized secant hyperbolic distribution (GSHD) was recently introduced as a modeling tool in data analysis. The GSHD is a unimodal distribution that is completely specified by location, scale, and shape parameters. It has also been shown elsewhere that the rank procedures of location are regular, robust, and asymptotically fully efficient. In this article, we study certain tail weight measures for the GSHD and introduce a tail-adaptive rank procedure of location based on those tail weight measures. We investigate the properties of the new adaptive rank procedure and compare it to some conventional estimators.     

Navigating norms and structures: young mothers’ pathways to economic independence

Understanding the complex relationships between childcare, education and work is crucial to acknowledging how young mothers express agency in their pathways to economic independence. Instead of considering them as a policy target group at risk for multiple reasons, this research reverses the perspective by focusing on young mothers’ agency in school and paid employment. The study is set in the Netherlands, where economic independence has become a focal point of social policy and practice, especially for young people. It explores how young mothers navigate norms and structures of education and employment, drawing on 18 months of participant observation and 41 semi-structured interviews with young mothers. Notions of ‘everyday’ and ‘bounded’ agency are used in analysing structural limitations (e.g. irregular working hours in ‘women’s jobs’, a lack of maternity leave at school) and norms (e.g. completing higher education and finding a good job versus being primary caretakers, enjoying children and being role models). School and workplace structures reinforce contradictory discourses of motherhood and economic independence. Young mothers exhibit agency in considering their options around job security, work experience, wages, student loans and spending time with children. In doing so, they navigate structural and normative collisions of economic independence and mothering.     

Career pathways for temporary workers: Exploring heterogeneous mobility dynamics with sequence analysis

Because temporary jobs are time-delimited, their implications for workers’ economic security depend not only on their current characteristics, but also their place in longer-term patterns of mobility. Past research has typically asked whether temporary jobs are a bridge to better employment or trap workers in ongoing insecurity, investigating this question by analyzing single transitions. We demonstrate that this approach is ill-suited to assessing the often more complex and turbulent employment patterns characteristic of temporary workers. Our analysis instead employs sequence methods to compare a representative sample of temporary workers’ month-by-month mobility patterns through 8 potential (non)employment states over five years. We derive a typology of trajectories and describe their relative precariousness in relation to employment stability and wage and earnings levels and growth. While some of the pathways correspond quite closely to frameworks used by past research, others reveal new and important distinctions. Multinomial logit models reveal job, employer, and worker characteristics associated with different pathways. Age, gender, and type of temporary work stand out as important factors shaping subsequent mobility patterns.     

基于随机p-鲁棒优化的国家血液战略储备库选址-库存模型

以往的救灾实践对建立国家血液战略储备体系提出了迫切要求。国家血液战略储备库的建设问题亟待解决。由于血液产品特性以及应急血液保障特性的存在，使得国家血液战略储备库的选址决策具有一定的复杂性。本文将问题定位为选址-库存问题。首先，以应急条件下血液保障及时度最高为目标，构建了一个不确定环境下考虑多情景、多血型、多阶段、带提前期、有容量限制、日常随机需求、有预算约束及协同定位的国家血液战略储备库选址-库存模型。同时，为了规避应急条件下的不确定风险，进一步构建了国家血液战略储备库选址-库存问题的随机p-鲁棒优化模型。该模型为离散非线性混合整数规划模型，难以快速精确求解。故基于模型性质，设计了相应的遗传算法。最后，设计了两组算例验证模型与算法的有效性。其中，第1组算例基于我国大陆地区31个省级血液中心与省级行政区的数据，并根据不同预算值给出6个算例，得到了国家血液战略储备库的选址-库存决策方案。第2组算例为6个不同规模的模拟算例，用来测试不同规模下的算法性能。算例结果表明：遗传算法的性能更好；鲁棒解与确定性模型最优值相差不大（最大差距≤1.08%），可降低不确定性导致的风险。实践中，可对本文所建模型稍作改进，应用于具有类似特征的易腐品（药品、粮食等）应急物资储备库选址-库存决策。     

Water cycle algorithm for solving the reliability-redundancy allocation problem with a choice of redundancy strategies

Abstract

This paper proposes a new mathematical model for the reliability-redundancy allocation problem (RRAP) with a choice of redundancy strategies. To maximize the reliability of a system, this model chooses the best redundancy strategy from among both active and standby ones for each subsystem. For those with a standby strategy, a continuous time Markov chain model is used to calculate the exact reliability values. In order to solve the proposed mixed-integer non-linear programing model, a powerful evolutionary algorithm, called water cycle algorithm (WCA), is developed and implemented on three famous benchmark problems. Finally, the results of different benchmark problems are compared with those previously reported to show the superiority of the proposed model and the efficiency of WCA.     

Get Full Text Research and the Search for Appropriate Copies

Abstract

A group of the largest academic publishers has launched a new service to simplify access to full-text research for users of discovery services and scholarly collaboration platforms. While this service aims to provide easy access to full-text articles using article-level entitlement information linked to institutions through Seamlessaccess.org, it also introduces ambiguity. The service allows for publishers to direct users to alternative versions when a full-text entitlement is not found for the user, though users may already be entitled to full text through providers that do not participate in the service. Depending on specific implementations, this could lead to further confusion and make it more difficult for users to find an appropriate copy.     

中国养老金:制度变革、问题清单与高质量发展

中国养老金制度经过近30多年来的深刻变革,从自我封闭的单位保障制走向开放式的社会保险制、从少数人的专利发展成为全体老年人的共同福祉、从单一责任主体走向多方分担责任、从单一层次走向多层次化,成为惠及所有老年人的社会保障制度,符合全球养老金制度发展的潮流与客观规律。但目前存在的理论认识误区、制度不统一、政策参数僵化、补充层次缺失及其导致的筹资失衡、待遇不公、预期紊乱、可持续性弱化和社会风险累积等问题正在日益显性化。这表明其仍是质量不高的制度安排。因此,中国养老金制度亟待走出逻辑混乱的思维定势与传统的路径依赖,通过明确公平建制理念、加快制度统一步伐、调适筹资责任分担机制、赋予相关参数弹性空间、理性推动多层次化等举措来为参与主体各方提供清晰稳定的预期,实现制度定型和高质量发展。