YouTubers’ networking activities during the 2016 South Korea earthquake

While YouTube has become an important social networking platform for risk and crisis communications, research into its role and use during environmental disasters has not been conducted. The present study investigates how Korean YouTubers reacted during the 2016 Gyeongju earthquakes. Two kinds of data were collected from the most popular YouTube clips on the earthquake (from AfreecaTV and YonHap news): the most frequently used words in the replies to the comments and the networked forums among YouTubers. Findings suggest that YouTube has become a channel for quickly increasing public awareness of crises and for promoting safety strategies. InDegree Centralization is higher in professional videos. Hierarchy measure’s value is one, which means the reply-to network is not two-way. There is sparse close-knittedness in amateur videos. Community clusters emerge in amateur videos over time. The results also reveal that YouTubers on AfreecaTV are more likely to express emotional opinions than their counterparts on YonHap news are.     

Modularization of hybrid censoring schemes and its application to unified progressive hybrid censoring

In this paper, a structural analysis of hybrid censoring models is presented. This new modularization approach to hybrid censoring models enables a convenient derivation of distributional results. For instance, it allows to derive the exact distribution of the MLEs under an exponential assumption for very complex hybrid scenarios. In order to illustrate the benefit of this idea, we apply it to four new unified progressive hybrid censoring schemes. They are extensions of already proposed unified Type-I/II/III/IV hybrid censoring schemes to progressively Type-II censored data. The resulting analysis shows that the modularization approach provides a powerful, efficient, and elegant tool to study even more complex hybrid censoring models.     

Application of Fuzzy Risk Analysis for Selecting Critical Processes in Implementation of SPC with a Case Study

Fuzzy risk analysis is widely used in risk assessment of components by linguistic terms. Fuzzy numbers are used to quantify the associated uncertainty. This study employs fuzzy risk analysis to evaluate processes for implementing statistical process control (SPC) in a specified manufacturing system. To reach this goal, fuzzy risk analysis has been applied based on both ranking and similarity of generalized trapezoidal fuzzy numbers in a stepwise procedure. Therefore, a new approach has been introduced for fuzzy risk analysis of processes to overcome the shortcomings of previous fuzzy risk analysis approaches. As a result, fuzzy risk analysis is used as a decision making technique to select critical processes under uncertainty. Also, the application of the proposed SPC implementation algorithm is illustrated in the manufacturing line of a car battery factory.     

The Coordinated Effect of a Merger with Balanced Sharing of Collusive Profits

It is hard to assess the coordinated effect of mergers in solid and convincing fashion, in part because economic theory deals mainly with the sustainability of tacit collusion and generally does not explore the conditions that foster collusion in the first place. Also the most popular schemes of collusion (Joint profit maximization and Nash Bargaining) proposed by the economic literature seem at odds with the evidence recorded on cartels and with the practical attitude of entrepreneurs. In this scenario the recent version of the Horizontal Merger Guidelines contained the interesting suggestion to pay attention to the process - parallel behaviour – which leads to collusive equilibria. Working on the same intuition we propose an approach based on the idea that firms can always find a feasible collusive agreement, for every possible value of the factor which discounts future profits. Assuming that in order to collude, firms demand the fair sharing of collusive gains, we exploit the egalitarian property of grim trigger strategies when all incentive compatibility constraints are binding. This approach suggests using three indicators to determine whether and how a merger affects the probability of collusion. An application of this approach to a real-world case (the AT&T/T-Mobile merger) is provided.