Robust panel unit root tests for cross-sectionally dependent multiple time series

Robust panel unit root tests are developed for cross-sectionally dependent multiple time series. The tests have limiting null distributions derived from standard normal distributions. A Monte Carlo experiment shows that the tests have better finite sample robust performance than existing tests. Some Latin American real exchange rates revealing many outlying observations are analyzed to check the purchasing power parity (PPP) theory.     

海外石油工程项目设备进出口清关模式选择

海外石油工程项目设备进出口两种清关模式各有利弊。结合具体案例，分析了设备进出口清关模式选择时要考虑的因素，探讨了设备进出口模式选择方案的优化途径。     

浅谈新形式下的高校物资采购工作

本文从高校物资采购的特点、存在的问题进行分析,结合我国高校的实际,提出了高校物资采购工作中一些措施和方法,实施阳光采购工程,提高资金的使用效率。     

基于ERP管控视角下的纺织企业缝隙成本优化

探讨基于ERP管控视角下纺织企业缝隙成本优化的问题。通过分析纺织行业特性与成本管理现状,发现在生产流程中存在缝隙成本,这些缝隙成本单位价值较小,但是数量巨大,汇聚起来相当可观。介绍了ERP的营业成本优化方案及ERP系统成本控制的效果。指出:由于企业成本管理制度设计不合理、财务业务流程不规范、全面预算没有被严格执行,管理粗放造成了纺织企业缝隙成本过高。认为:要降低纺织企业成本,减少缝隙成本,关键在于精细化管理,利用企业资源计划可有效控制成本、预防风险,实现纺织企业经济利益最大化。     

A general quantity discount and supplier selection mixed integer programming model

Recently, new models and heuristics for exploiting quantity discounts have been proposed that are applicable in classical purchasing as well as in an e-business environment and can be implemented as part of an advanced planning system. These models can now handle both the single- and multi-item case with fixed cost to be shared among several products ordered at the same point in time from a single supplier. Furthermore, the supplier selection problem is addressed, i.e., how to best exploit quantity discounts over time offered by several suppliers. Last but not least, additional constraints on the buyer’s or on the supplier’s side may be included. While so far only purpose-built heuristics have been proposed for this generalized problem, we present a linear mixed integer programming (MIP) model, which not only represents the all-units discount but also the incremental discount case. Furthermore, the objective function chosen resolves (former) conflicts among proponents of a purely cost oriented and a cash flow oriented modeling approach. Computational tests show that our model yields near optimal solutions within a given CPU time limit by making use of a standard MIP solver.     

基于Struts和Hibernate的电子申购系统

通过对现代物资申购作业的系统分析，在J2EE的B／S应用架构下，以Struts作为表现层框架、Hibernate作为数据持久层框架，设计了一个电子申购系统。并利用柔性构件技术、XML数据标准和Java语言实现。该系统效率高、职责明确、反馈快捷、方便，并具有良好的可扩展性、实用性和可维护性。     

Customer engagement behaviour on social commerce platforms: An empirical study

Web 2.0 applications and social media have transformed e-commerce into a new business paradigm, which is called social commerce. This development has changed the customers’ role and has empowered them by placing them in a unique position for influencing other buyers and providing guidance in purchasing decisions. Although a substantial amount of research has been conducted on customer behaviour, the understanding of the factors that influence customer engagement behaviour is limited, particularly in the social commerce context. This limitation is due to a lack of theoretical models for explaining such behaviour. In this study, the important factors that drive customer engagement on social commerce platforms are extracted from the literature. Drawing from social support theory, social presence theory, uses and gratifications theory, and the information system success model, we propose a new model for social commerce customer engagement. A survey-based empirical study with 203 respondents was conducted. The results demonstrated that customer engagement behaviour is strongly determined by social interaction, technological factors (interactivity and system quality), and motivational factors (hedonic and utilitarian motivations and perceived value). Among these factors, perceived value and social interaction had the most significant impacts on customer engagement behaviour on social commerce platforms. The theoretical and practical implications of the findings are discussed.     

民营书商参与高校图书现采工作探析

从民营书商参与图书现采的背景出发,分析了民营书商参与图书现采的优缺点,并对其未来的发展趋势提出了看法。     

An efficient optimal algorithm for the quantity discount problem in material requirement planning

An optimal algorithm based on branch-and-bound approach is presented in this paper to determine lot sizes for a single item in material requirement planning environments with deterministic time-phased demand and constant ordering cost with zero lead time, where all-units discounts are available from vendors and backlog is not permitted. On the basis of the proven properties of optimal order policy, a tree-search procedure is presented to construct the sequence of optimal orders. Some useful fathom rules have been proven, which make the algorithm very efficient. To compare the performance of this algorithm with the other existing optimal algorithms, an experimental design with various environments has been developed. Experimental results show that the performance of our optimal algorithm is much better than the performance of other existing optimal algorithms. Considering computational time as the performance measure, this algorithm is considered the best among the existing optimal algorithms for real problems with large dimensions (i.e. large number of periods and discount levels).     

Retracted: Antecedents and Consequences of Gender Swapping in Online Games

This study examines the reasons underlying gender swapping and its impacts on online gaming behavior. While previous studies considered gender swapping to be an abnormal or rare exception in one's self‐presentation, this study hypothesized that people swap genders as a rational choice based on practical benefits. An online survey was conducted with 318 male players of MMORPGs in Korea. Players swapped gender in games to gain benefits from other players under the condition of anonymity rather than to represent their own gender identity. Men playing female avatars displayed more socially amiable behaviors conventionally characterized as more feminine. Moreover, players were more willing to purchase virtual goods to decorate their gender swapped avatars, mediated by their emotional attachment to their avatar.