The Effects of Multitasking on Operations Scheduling

This study considers a typical scheduling environment that is influenced by the behavioral phenomenon of multitasking. Under multitasking, the processing of a selected job suffers from interruption by other jobs that are available but unfinished. This situation arises in a wide variety of applications; for example, administration, manufacturing, and process and project management. Several classical solution methods for scheduling problems no longer apply in the presence of multitasking. The solvability of any scheduling problem under multitasking is no easier than that of the corresponding classical problem. We develop optimal algorithms for some fundamental and practical single machine scheduling problems with multitasking. For other problems, we show that they are computationally intractable, even though in some cases the corresponding problem in classical scheduling is efficiently solvable. We also study the cost increase and value gained due to multitasking. This analysis informs companies about how much it would be worthwhile to invest in measures to reduce or encourage multitasking.     

Keep Your Friends Close? Supply Chain Design and Disruption Risk

In this article, we evaluate the relationship between supply chain design decisions and supply chain disruption risk. We explore two supply chain design strategies: (i) the dispersion of supply chain partners to reduce supply chain disruption risk versus (ii) the co‐location of supply chain partners to reduce supply chain disruption risk. In addition, we assess supply chain disruption risk from three perspectives: the inbound material flow from the supplier (supply side), the internal production processes (internal), and the outbound material flow to the customer (customer side) as a disruption can occur at any of these locations. We measure disruption risk in terms of stoppages in flows, reductions in flow, close calls (disruptions that were prevented at the last minute), disruption duration (time until normal operation flow was restored), and the spread of disruptions all the way through the supply chain. We use seemingly unrelated regression (SUR) to analyze our data, finding that lead times, especially supply side lead times, are significantly associated with higher levels of supply chain disruption risk. We find co‐location with suppliers appears to have beneficial effects to the reduction of disruption duration, and, overall supply side factors have a higher impact when it comes to supply chain disruption risk than comparable customer side factors.     

Mixed-effects Models with Skewed Distributions for Time-varying Decay Rate in HIV Dynamics

After initiation of treatment, HIV viral load has multiphasic changes, which indicates that the viral decay rate is a time-varying process. Mixed-effects models with different time-varying decay rate functions have been proposed in literature. However, there are two unresolved critical issues: (i) it is not clear which model is more appropriate for practical use, and (ii) the model random errors are commonly assumed to follow a normal distribution, which may be unrealistic and can obscure important features of within- and among-subject variations. Because asymmetry of HIV viral load data is still noticeable even after transformation, it is important to use a more general distribution family that enables the unrealistic normal assumption to be relaxed. We developed skew-elliptical (SE) Bayesian mixed-effects models by considering the model random errors to have an SE distribution. We compared the performance among five SE models that have different time-varying decay rate functions. For each model, we also contrasted the performance under different model random error assumptions such as normal, Student-t, skew-normal, or skew-t distribution. Two AIDS clinical trial datasets were used to illustrate the proposed models and methods. The results indicate that the model with a time-varying viral decay rate that has two exponential components is preferred. Among the four distribution assumptions, the skew-t and skew-normal models provided better fitting to the data than normal or Student-t model, suggesting that it is important to assume a model with a skewed distribution in order to achieve reasonable results when the data exhibit skewness.     

新冠肺炎疫情突发期政策制定的特征分析与效果评价 ——基于江苏省疾病预防控制中心的田野观察

文章聚焦政策本身,采用在江苏省疾病预防控制中心进行田野观察的研究方法,收集新型冠状病毒肺炎（简称新冠肺炎）疫情突发期的政策并进行文本分析,主要讨论政策文本发布时间的分布态势、发布单位、发布形式和政策内容4个方面。研究发现,在新冠肺炎疫情突发期（2020年1月15日至1月31日）国家级和省级指导性文件数量锐增。以江苏省为例,省级政策发文单位单一、文本类型多为通知类,起到了应对突发公共卫生事件时的及时反馈、迅速应急以及布置指导的作用。政策发布主体联防联控的及时应对性以及对政策文本的长效性考虑上尚有欠缺。总结政策制定的规律、原则以及经验,提出公共卫生事件突发期的政策观念应从单一权威主义走向多元协作,政策导向应从“战”时应急转向“平战结合”,政策价值应从“短期”应急转向“常态化”指导。     

海河图书馆应用地下储能技术的可行性分析

海河图书馆是天津市海河开发规划确定的公建项目.按照天津市政府提出的建筑应达到"三步节能"的要求,该项目已被列入天津市节能建筑示范工程.     

袁宏道净土思想略论

明代著名辅教居士袁宏道,早年矢志参禅,洞有所入.然亦颇沾"狂禅"习气,一悟便休,不究如来之了义、不知达摩之玄机,空腹高心,卑视净土法门,甚至于呵佛骂祖、斥教遮相.所幸生死心切,故能触机猛省,毅然摒弃偏空之见,悟修并重,乘戒兼行,豁悟达摩祖师说罪福之皆虚与永明延寿和尚言万善之总是,均为祛迷拯溺之论,实无彼此抵牾之处.于是至诚归心净土,借念佛之警切提醒参禅之深心,复藉参门之洞彻坚固净土之信行.嗣后,为广利蹇滞浊界之群生,特别是为指示深陷宗教歧路和禅净宿疑而不能自拔之士,袁宏道更深入普贤愿海,博综经论,撰成《西方合论》十卷,力主净土诸经与《大方广佛华严经》、《法华经》的不分优劣,并融贯教理、广破邪疑,直开正信、径指趣归.     

Two-Group Classification Using Neural Networks*

Artificial neural networks are new methods for classification. We investigate two important issues in building neural network models; network architecture and size of training samples. Experiments were designed and carried out on two-group classification problems to find answers to these model building questions. The first experiment deals with selection of architecture and sample size for different classification problems. Results show that choice of architecture and choice of sample size depend on the objective: to maximize the classification rate of training samples, or to maximize the generalizability of neural networks. The second experiment compares neural network models with classical models such as linear discriminant analysis and quadratic discriminant analysis, and nonparametric methods such as k-nearest-neighbor and linear programming. Results show that neural networks are comparable to, if not better than, these other methods in terms of classification rates in the training samples but not in the test samples.     

习近平总书记关于高校体育工作重要论述的逻辑意蕴与实践路径

习近平总书记关于高校体育工作重要论述是新时代中华民族所认同体育文化的价值取向、精神气质、思维方式与行动纲要的总和,它是大学生思想教育工作发展创新的内在需要。高校通过以中华体育文化精神为基石,融入社会主义主流价值;优化体育文化育人环境,让体育文化叫好又叫座;深入挖掘体育文化活动内涵,打造经典体育文化品牌;丰富体育文化载体形式,使体育文化育人产生倍增效果,多种实践途径践行习近平总书记关于高校体育工作的重要论述,促推中华民族体育强国梦的实现。     

What is Integration? A Comparative View from Immigrants and Municipal Policy

The ongoing project of citizenship construction in societies receiving international immigration demands a perspective that takes into account the interests, views and needs of all socio-demographic groups, including those of newcomers as potential new citizens. We interviewed representatives of 16 immigrant associations operating in the Spanish autonomous community of Galicia, reviewed immigration policy in 13 Spanish (Galician) municipalities, and interviewed 20 municipal government staff members who put these into practice. With this research, we aim to explore the perspectives of immigrants with respect to their own integration and to examine how these compare with local policies designed to facilitate these processes. By comparing the immigrant representatives' perceptions with local policy discourses and practice, our study reveals how local integration practice is not only inconsistent with its own policy discourse but also fails to consider and include immigrants' own understandings of what integration means and how it can be achieved.