A computational analysis of the tournament equilibrium set

A recurring theme in the mathematical social sciences is how to select the “most desirable” elements given a binary dominance relation on a set of alternatives. Schwartz’s tournament equilibrium set (TEQ) ranks among the most intriguing, but also among the most enigmatic, tournament solutions proposed so far. Due to its unwieldy recursive definition, little is known about TEQ. In particular, its monotonicity remains an open problem to date. Yet, if TEQ were to satisfy monotonicity, it would be a very attractive solution concept refining both the Banks set and Dutta’s minimal covering set. We show that the problem of deciding whether a given alternative is contained in TEQ is NP-hard, and thus does not admit a polynomial-time algorithm unless P equals NP. Furthermore, we propose a heuristic that significantly outperforms the naive algorithm for computing TEQ.     

Building dynamic capabilities for digital transformation: An ongoing process of strategic renewal

In this qualitative study, we explore how incumbent firms in traditional industries build dynamic capabilities for digital transformation. Digital transformation has been defined as the use of new digital technologies, such as mobile, artificial intelligence, cloud, blockchain, and the Internet of things (IoT) technologies, to enable major business improvements to augment customer experience, streamline operations, or create new business models. In making sense of digital transformation, we discovered that leaders in various industry circles use the term inconsistently to describe various strategizing and organizing activities; in addition, the term has gained limited scholarly attention as a context for study of strategic change. Drawing on senior executives' experiences with leading digitalization projects at incumbent firms, we propose a process model comprising of nine microfoundations to reveal the generic contingency factors that trigger, enable, and hinder the building of dynamic capabilities for digital transformation. Our findings reveal that digital transformation is an ongoing process of using new digital technologies in everyday organizational life, which recognizes agility as the core mechanism for the strategic renewal of an organization's (1) business model, (2) collaborative approach, and eventually the (3) culture.     

Do individual investors learn from their mistakes?

Based on recent empirical evidence which suggests that as investors gain experience, their investment performance improves, we hypothesize that the specific mechanism through which experience translates into better investment returns is closely related to learning from investment mistakes. To test our hypotheses, we use an administrative dataset which covers the trading history of 19,487 individual investors. Our results show that underdiversification and the disposition effect do not decline as investors gain experience. However, we find that experience correlates with less portfolio turnover. We conclude that compared to other investment mistakes, it is relatively easy for individuals to identify and avoid costs related to excessive trading activity. When correlating experience with portfolio returns, we find that as investors gain experience, their portfolio returns improve. A comparison of returns before and after accounting for transaction costs reveals that this effect is related to learning from overtrading.     

Residents’ Reactions to Earthquake Early Warnings in Japan

This article empirically examines the effectiveness of earthquake early warning (EEW) in Japan based on experiences of residents who received warnings before earthquake shaking occurred. In Study 1, a survey (N = 299) was conducted to investigate residents’ experiences of, and reactions to, an EEW issued in Gunma and neighboring regions on June 17, 2018. The main results were as follows. (1) People's primary reactions to the EEW were mental, not physical, and thus motionless. Most residents stayed still, not for safety reasons, but because they were focusing on mentally bracing themselves. (2) Residents perceived the EEW to be effective because it enabled them to mentally prepare, rather than take physical protective actions, before strong shaking arrived. (3) In future, residents anticipate that on receipt of an EEW they would undertake mental preparation as opposed to physical protective actions. In Study 2, a survey (N = 450) was conducted on another EEW issued for an earthquake offshore of Chiba Prefecture on July 7, 2018. Results were in line with those of Study 1, suggesting that the findings described above are robust. Finally, given people's lack of impetus to undertake protective action on receipt of an EEW, this article discusses ways to enhance such actions.     

Internet Use and Volunteering: Relationships and Differences Across Age and Applications

VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations - The internet plays an important part in our daily lives. In this paper, we ask whether internet use is negatively related...     

Unknown outcomes,no guarantees: Lawrence Grossberg and experimentation

This article explores notions of experimentation embedded in Lawrence Grossberg’s writings. It begins by proposing that experimentation is a particularly relevant expression of the stakes of Grossberg’s research, and also one that embodies the ‘unknownness’ characteristic of rigorous intellectual work more broadly. By embracing unknownness in its contextual specificity (the shorthand for which is the phrase ‘without guarantees’), one seeks to open the present to a range of potential futures – a process requiring interdisciplinary collaboration and institutional risk-taking. This article then moves on to consider how Grossberg’s work brings to light the relationship between popular imagination and experimentation; that is, he understands the popular as a territory where people can be won for experimentation in paradoxically unknown but knowable futures. Finally, the piece heeds Grossberg’s warning against the fetishization of experimentation in certain political and theoretical formations, notably his repeated cautions against experimentation divorced from the specificity and requirements of the conjuncture. The article concludes by calling for a rigorous mapping of the terrain of Cultural Studies in order to foster and sustain the interdisciplinary, well-grounded experimentation to which its future must be bound.     

Improving sample size recalculation in adaptive clinical trials by resampling

Sample size calculations in clinical trials need to be based on profound parameter assumptions. Wrong parameter choices may lead to too small or too high sample sizes and can have severe ethical and economical consequences. Adaptive group sequential study designs are one solution to deal with planning uncertainties. Here, the sample size can be updated during an ongoing trial based on the observed interim effect. However, the observed interim effect is a random variable and thus does not necessarily correspond to the true effect. One way of dealing with the uncertainty related to this random variable is to include resampling elements in the recalculation strategy. In this paper, we focus on clinical trials with a normally distributed endpoint. We consider resampling of the observed interim test statistic and apply this principle to several established sample size recalculation approaches. The resulting recalculation rules are smoother than the original ones and thus the variability in sample size is lower. In particular, we found that some resampling approaches mimic a group sequential design. In general, incorporating resampling of the interim test statistic in existing sample size recalculation rules results in a substantial performance improvement with respect to a recently published conditional performance score.     

Strong shareholder rights,internal capital allocation efficiency,and the moderating role of market competition and external financing needs

Review of Managerial Science - This study investigates the effect of strong shareholder rights on the internal capital allocation efficiency of multi-segment firms and how market competition and...     

确保从研究到开发界面的有效管理 --R&D个体的知识转移管理

在技术密集型公司中一个重要的问题是构建"无隔层创新流程"(seamlessinnovationprocesses)."这里无发明"(not-invented-here,NIH)综合症和其它的障碍严重影响着研究和开发之间知识和技术的有效转移.由于存在着保守型结构、过时的转移设备以及下游职能定位模糊等原因,知识转移经常失败.从研究到开发产生障碍的原因主要有以下几方面:职能分割、地理位置、专业偏好和文化背景等.首先,我们在25家公司做了100多次的半结构性访谈;然后,我们在技术密集型产业做深入的案例研究.改进从研究到开发的界面总是围绕着R&D个体展开.我们通过对ABB、Hitachi、IBM、Kao、Unisys以及xerox等公司的案例分析,得出了一些成功的实践经验.我们得出这样的结论:从研究到开发界面的有效管理通过对管理R&D个体的知识转移获得.     

Keep it simple: estimation strategies for ordered response models with fixed effects

By running Monte Carlo simulations, we compare different estimation strategies of ordered response models in the presence of non-random unobserved heterogeneity. We find that very simple binary recoding schemes deliver parameter estimates with very low bias and high efficiency. Furthermore, if the researcher is interested in the relative size of parameters the simple linear fixed effects model is the method of choice.