Complex Network of Aviation E-Services in the Belt and Road Initiative: A Heuristic Study of Small Data based on Block Modeling

ABSTRACT

The aviation e-service system is an important part of support for business communication in regions covered by Belt and Road initiative. In exploring the role of airline companies in this system, we examine the structure of the network, which consists of airlines interconnections based on small data of individual attributes of aviation companies in aviation e-services, and study these interconnections across different groups using block modeling. The heuristic solution of airline companies in development of international communication and cooperation is further discussed. Among our policy implications for global managers, we suggest the enhancement of cross-regional cooperation among airlines.     

Addressing the sustainable development through sustainable procurement: What factors resist the implementation of sustainable procurement in Pakistan?

Sustainable Public Procurement is an integral part of sustainable development because of ever increasing government expenditures. Most of the developing countries lack the required infrastructure which may support public sector sustainability. The aim of this study is to assess the critical factors which resist the implementation of sustainable procurement in public sector of Pakistan. We used Interpretive Structural Model to investigate and rank the interrelationships among different factors of sustainable procurement. With the help of literature and Likert scale instrument, we found twelve key barriers that resist sustainable procurement implementation. We also examined tender documents of 75 different public sector universities of Pakistan but found absence of sustainability element in the documents. External factors namely government legislation and stakeholders' pressure are found most critical barriers as compared to inter organizational factors. The study is also important to highlight the hurdles in the way of sustainable development. First, the government must introduce rules and regulations to implement the sustainable procurement. Stakeholders and donors must put pressure on organizations for adopting sustainable procurement. Sustainability education should be made mandatory part of curriculum and employees should be given regular training on sustainability. Further, public procurement policies at government and institutional levels are required to be revisited towards a circular economy.     

From rationality to hyperreality: paradigm poker

This paper, following McGoun's (1997) seminal article comparing the economy of financial securities to a hyperreal poker game, argues that finance and accounting researchers should take the “linguistic turn” that has rejuvenated theory and research in many, if not most, of the social science and humanities in recent decades. In general terms, this means following Ludwig Wittgenstein's language game paradigm rather than Karl Popper's scientific deductive hypothesis testing methodology. The paper illustrates this by drawing on some of Jean Baudrillard's' ideas, particularly his concept of hyperreality and his phases of the image theoretic.The paper presents a poststructuralist genealogical analysis of the radical ruptures and reformulation of the meaning attributed to the accounting sign of earnings over the feudal, counterfeit, production, and simulation eras. It concludes that, as with many other signs in contemporary society, the earnings sign no longer has any relationship with, nor does it any longer refer to, any real or intrinsic profit but instead floats ungrounded in today's financial economy.The paper recommends that researchers in finance and accounting adopt paradigms from literary theory, semiotics, linguistics, and semiology rather than continue to rely on economics-based theory, which has lost its power for explaining and predicting happenings in today's financial economy of self-referencing models and images.     

Diffusion of Products with Limited Supply and Known Expiration Date

In this paper, we provide a model for diffusion of products, which are available in limited quantity until a known expiration date, after which the unsold products have no value. We consider the case of a performing arts company. The model development is built on the foundation of classical product diffusion model by Bass (1969) and the psychological effect known as the scarcity principle (Cialdini, 1985). Our empirical analysis results show that the proposed model can provide significant improvement in prediction of the products characterized by the scarcity effect.     

物流合理配送问题的多阶段建模优化求解方法

简述了现有货物配装问题在实际应用中的缺陷,并针对货物配送问题,提出了多阶段建模优化求解方法,并应用于实例中。实例证明该方法所求得的最优解更具合理性和实际意义。     

林产品市场模型文献综述

关于林产品市场的数量研究开始于上个世纪50年代。早期的研究主要以时间序列数据为主。近几十年来,由于经济理论在林产品市场模型中的应用,模型估计方法的改进,以及详细数据的获得,林产品市场模型越来越完善。文章对近几十年来出现的主要建模方法,及其应用作一回顾,并对这些方法的优缺点作简单的比较。     

Robustness issues in multilevel regression analysis

A multilevel problem concerns a population with a hierarchical structure. A sample from such a population can be described as a multistage sample. First, a sample of higher level units is drawn (e.g. schools or organizations), and next a sample of the sub‐units from the available units (e.g. pupils in schools or employees in organizations). In such samples, the individual observations are in general not completely independent. Multilevel analysis software accounts for this dependence and in recent years these programs have been widely accepted. Two problems that occur in the practice of multilevel modeling will be discussed. The first problem is the choice of the sample sizes at the different levels. What are sufficient sample sizes for accurate estimation? The second problem is the normality assumption of the level‐2 error distribution. When one wants to conduct tests of significance, the errors need to be normally distributed. What happens when this is not the case? In this paper, simulation studies are used to answer both questions. With respect to the first question, the results show that a small sample size at level two (meaning a sample of 50 or less) leads to biased estimates of the second‐level standard errors. The answer to the second question is that only the standard errors for the random effects at the second level are highly inaccurate if the distributional assumptions concerning the level‐2 errors are not fulfilled. Robust standard errors turn out to be more reliable than the asymptotic standard errors based on maximum likelihood.     

三维激光扫描仪在地形测量中的应用

文章从三维激光扫描仪在测量中的作用入手,详细介绍了三维激光扫描仪的工作原理和三维激光扫描系统,并说明了三维激光扫描仪配套三维数据处理软件的功能,着重介绍了三维数据的处理方法:点云的连接、特征线的提取、对地物的三维建模(TIN建模),在TIN建模中,介绍了狄洛尼三角网的构网方法。     

Preventing HIV in injection drug users: exploring the tradeoffs between interventions

Injection drug users (IDUs) transmit the human immunodeficiency virus (HIV) via both needle sharing and sex. Available interventions for this population have varying costs and effectiveness and focus on different risk behaviors. In this analysis, we look at two interventions. One is inexpensive, broad-based and provides modest risk reductions (street outreach (SO)); the other is narrowly focused, expensive and relatively effective (methadone maintenance). This analysis explores the effects of population risk behavior, intervention effectiveness, intervention costs, and decision constraints when allocating funds between these two interventions to maximize effectiveness. We develop a model of the spread of HIV, dividing IDUs into susceptibles (uninfected) and infectives, and separately portraying sex and injection risk. We simulate the epidemic in New York City for time periods from the mid-1980s to the early 1990s, and incorporate the behavioral effects of two interventions performed singly or in combination to find the allocation that maximizes the number of infections averted in the IDUs and their noninjecting sex partners, assuming interventions have increasing marginal costs. We find that the optimal allocation nearly always involves spending the maximum allowable amount on SO. This result is largely insensitive to variations in risk parameters, intervention efficacy, or cost. The model's structure, however, makes clear that many factors contribute to this insensitivity, namely the scope of the interventions, the dual drug/sex nature of HIV risk in the population, the asymmetry of sexual risk for men and women, and the potential benefits to nonIDUs.     

在工程项目管理中实施过程管理的研究

传统的建设过程彼此分裂的特性，严重影响着工程建设的效率性和有效性。本文结合过程管理的思想，分析工程项目实施和管理的系统过程，探讨工程项目管理过程的识别与建立，并在此基础上提出建立工程项目管理的过程模型的方法。