Is it one break or ongoing permanent shocks that explains U.S. real GDP?

The relative importance of permanent versus cyclical shocks to GDP has been found to depend on the presence or absence of a single break in mean growth. We estimate unobserved components models conditional on a trend break having occurred in any specified quarter and use the Bayesian model averaging to combine the conditional estimates. We estimate a break occurred around 2006:1. Allowing for a break significantly reduces estimates of trend variance. However, enough spread remains in the posterior distribution to indicate that available data does not definitively settle the question of the relative importance of trend versus cycle.     

Evaluating intergenerational risks

Climate policies have stochastic consequences that involve a great number of generations. This calls for evaluating social risk (what kind of societies will future people be born into) rather than individual risk (what will happen to people during their own lifetimes). We respond to this call by proposing and axiomatizing probability adjusted rank-discounted critical-level generalized utilitarianism (PARDCLU) through a key axiom ensuring that the social welfare order both is ethical and satisfies first-order stochastic dominance. PARDCLU yields a new useful perspective on intergenerational risks, is ethical in contrast to discounted utilitarianism, and avoids objections that have been raised against other ethical criteria. We show that PARDCLU handles situations with positive probability of human extinction and is linked to decision theory by yielding rank-dependent expected utilitarianism—but with additional structure—in a special case.     

Evaluating information diffusion speed and its determinants in social media networks during humanitarian crises

The rapid diffusion of information is critical to combat the extreme levels of uncertainty and complexity that surround disaster relief operations. As a means of gathering and sharing information, humanitarian organizations are becoming increasingly reliant on social media platforms based on the Internet. In this paper, we present a field study that examines how effectively information diffuses through social media networks embedded in these platforms. Using a large dataset from Twitter during Hurricane Sandy, we first applied Information Diffusion Theory to characterize diffusion rates. Then, we empirically examined the impact of key elements on information propagation rates on social media. Our results revealed that internal diffusion through social media networks advances at a significantly higher speed than information in these networks coming from external sources. This finding is important because it suggests that social media networks are effective at passing information along during humanitarian crises that require urgent information diffusion. Our results also indicate that dissemination rates depend on the influence of those who originate the information. Moreover, they suggest that information posted earlier during a disaster exhibits a significantly higher speed of diffusion than information that is introduced later during more eventful stages in the disaster. This is because, over time, participation in the diffusion of information declines as more and more communications compete for attention among users.     

WHICH AGGLOMERATION EXTERNALITIES MATTER MOST AND WHY?

This paper revisits the ongoing discussion on the importance of agglomeration externalities – specifically specialization, diversity and competition effects – that may contribute to innovation, productivity and urban employment growth. Previous meta‐analyses suggested that the evidence on agglomeration externalities is strongly context‐specific. Expanding an earlier analysis of 31 articles, we seek to draw in this paper more robust conclusions by means of the statistical evidence for agglomeration externalities presented in 73 scientific articles, all building on the seminal work of Glaeser et al. (1992). Our results confirm that the heterogeneity among studies is huge and can only be partially accounted for by means of an ordered probit analysis. Additionally, some evidence of publication bias is found. We conclude that the conventional lines of inquiry in this literature may now have reached strongly diminishing returns. New lines of inquiry, using rich micro‐level data on firms and workers, dynamic general equilibrium models at the macro level, more attention for spatial and temporal variation in the impacts of agglomeration, and further investigations into the spatial scope of externalities are promising avenues for further research that can enhance our understanding of how agglomeration externalities continue to fuel our increasingly urbanized world.     

全货运航空公司单分配严格枢纽航线网络优化设计

针对全货运航空公司，研究其货运航线网络的构建问题。基于单分配严格枢纽航线网络，对传统模型进行改进。以各航线上货物的委托运输成本和自有机队的运输成本，取代传统的单位运输成本和折扣因子，考虑枢纽点的中转成本和载运率对路径选择的影响。结合航空货运夜航的特征考虑各机队夜间可用时间的限制，以总成本最小为目标，构建数学模型，采用LINGO优化软件求解，验证模型的有效性，为全货运航空公司构建货运航线网络提供参考。     

Classification of micro,small and medium enterprises (M-SME) based on their available levels of knowledge

This paper proposes a novel and practical method of classifying micro, small and medium enterprises (M-SME) based on their available levels of knowledge. This classification considers that the specific problems that dominate a company’s operations are related to the level of knowledge available. Therefore, identifying the dominant problem groups facing the company can enable an estimate of the level of knowledge available in the enterprise.Data from 2698 Mexican M-SMEs are used to identify operational problems. The main problem groups are obtained through a cluster analysis. The proposed classification consists of three levels of knowledge based on the interpretation of the dominant problem groups in each enterprise. Each of the 2698 Mexican M-SME are classified by a discriminant analysis.Nearly half of the M-SME are classified as having a lower level of available knowledge, and only 10% are classified with the highest level. No difference is observed between the size of the company and the level of available knowledge. This means that growth in the number of employees and sales of M-SMEs is not necessarily accompanied by an accumulation of knowledge that companies can use to improve their operations.     

The Organizational Innovation System: A systemic framework for radical innovation at the organizational level

Most research on innovation management at the organizational level has typically been focused on one specific innovation project phase or innovation management concept. This has resulted in many valuable insights, though scattered in different (innovation) research fields and studies. With the development of the Organizational Innovation System (OIS), we bring together important insights from the Innovation Systems, Open Innovation and other related fields into a guiding concept useful for both innovation managers developing (radical) innovations and innovation scholars. In this paper, we define the OIS and its key structural components, and discuss the identified functions and categories of potential imperfections. With the OIS, we provide a holistic, hands-on concept currently lacking in the open innovation approach. From the conceptualization, a framework for analysis is put forward which provides structure to the study of ongoing and finished innovation processes. Additionally, the development of the OIS is a first step in the development of a currently underdeveloped micro-level within the innovation systems perspective. The insights in OISs and the future insights derived from analytical efforts, will not only be beneficial for the performance of innovating organizations and organizational innovation systems but also for the performance of the higher, interconnected system levels.     

Service quality of airports' food and beverage retailers. A fuzzy approach

Nowadays the profitability of airports is largely based on non-aeronautical or commercial activities, and particularly on retail and food and beverage services. Further, researchers concur that shopping, eating and drinking in airports have to be considered an important part of tourists' experience and activities that can significantly enhance or damage the tourist destination image. Despite this, there is still little research that analyses how service quality (SQ) is perceived by passengers consuming food and beverages (F&B) in airport areas. This study aims to deepen the scientific debate on this topic. Specifically, this study applies fuzzy numbers with a sample of 551 passengers flying from Olbia-Costa Smeralda Airport (Sardinia Region, Italy) with the aim of determining how they perceive the SQ delivered by F&B retailers and whether age plays a determinant role in segmentation. Findings reveal which F&B features outperform others; furthermore, they show that age is a moderating factor in consumer satisfaction, with older passengers being less satisfied than their counterparts. This study adds knowledge to the literature devoted to SQ, applying a fuzzy number approach to the under-investigated research area related to F&B consumption in airport areas. Further, it provides information useful to airport managers on the features of F&B services that are most important in shaping consumer satisfaction, based also on their age. Limitations of the study are also discussed and suggestions for future research are given.     

Impact of a sustainable brand on improving business performance of airport enterprises: The case of Incheon International Airport

This research attempted to help understand brand management from a new perspective suited to the digital age. The purpose of this research is to empirically analyze direct and indirect influences on the relationships between sustainable brands and the enhancement of airport business performance by examining the relationships between social media, transparency, social responsibility, sustainable brand and airport business performance. For this testing, 304 questionnaires were collected from employees of Incheon International Airport. Results of the testing indicated that social media, transparency, and social responsibility had a significant influence on airport business performance through a sustainable brand. It was found that the mediation effect of a sustainable brand was significant as well. Results of this research are meaningful in that they provide implications and insights for enterprise brand management in the digital environment.     

Comparing efficiency of holding business model and individual management model of airports

This research compares the efficiency of holding business model to individual management model of airports, employing some robust non-parametric partial frontier-based methods to compare the statistical distributions of efficiency, under different scenarios, to find out which group of airports yields better global performance. The comparison between groups will follow a Malmquist index decomposition, which seems to be the most appropriate tool for within- and inter-group performance comparison. For this purpose, a sample of 145 airports from three continents is utilized. The results provide evidence that European airports are the most productive ones, and within this cluster, the individual management model presented a significant frontier shift with respect the holding cluster frontier, meaning that the former is much more productive than the latter.