Ranked sparsity: a cogent regularization framework for selecting and estimating feature interactions and polynomials

AStA Advances in Statistical Analysis - We explore and illustrate the concept of ranked sparsity, a phenomenon that often occurs naturally in modeling applications when an expected disparity exists...     

The Body in Mind: Mead's Embodied Cognition

This article highlights the role played by the body in the work of George Herbert Mead. For Mead, the social emergence of mind depends on human physiology. This is revealed through a detailed exploration of three thematic domains in his work: the organism–environment dyad, perception, and the manipulatory stage of the act. From this, I argue that Mead saw the body as constitutive of cognition and central to the development of mind and self. Present-day research supports this view and demonstrates Mead's relevance for understanding embodied cognition.     

Predicting the Daily Covariance Matrix for S&P 100 Stocks Using Intraday Data—But Which Frequency to Use?

This article investigates the merits of high-frequency intraday data when forming mean-variance efficient stock portfolios with daily rebalancing from the individual constituents of the S&P 100 index. We focus on the issue of determining the optimal sampling frequency as judged by the performance of these portfolios. The optimal sampling frequency ranges between 30 and 65 minutes, considerably lower than the popular five-minute frequency, which typically is motivated by the aim of striking a balance between the variance and bias in covariance matrix estimates due to market microstructure effects such as non-synchronous trading and bid-ask bounce. Bias-correction procedures, based on combining low-frequency and high-frequency covariance matrix estimates and on the addition of leads and lags do not substantially affect the optimal sampling frequency or the portfolio performance. Our findings are also robust to the presence of transaction costs and to the portfolio rebalancing frequency.     

Moral Aspects of Executive Leadership

This paper argues that the crisis in management is a crisis in leadership and that the heart of leadership is the moral challenge for managers to see themselves and others as colleagues and collaborators. The search for a new leadership paradigm is a call to foster the human spiritual dimension which respects the deepest concerns and values of everyone in the enterprise. Islamic beliefs and heritage provide a natural basis for transformational leadership and for implementing a paradigm shift which integrates spirituality and work. This revised version was published online in July 2006 with corrections to the Cover Date.     

Leaders' narrative sensemaking during LMX role negotiations: Explaining how leaders make sense of who to trust and when

This investigation supplements Leader–Member Exchange (LMX) theory by explaining how leaders make sense of whether and when to trust members throughout role negotiations. This conceptualization of leaders' trust of members describes how leaders emplot members in storylines characterized as predictably good, unpredictable, or predictably bad, and catalogs the formal communication practices indicative of those predictions. Forty working adults, who have reputations for being effective leaders, were interviewed. Constant comparative analysis revealed leaders attempted to produce stories with characterological coherence about members' character development throughout role negotiations. The Leader-to-Member Narrative Sensemaking of Trust (LMNST) concept describes how participants reported trusting and doubting (often simultaneously) their members by evoking combinations of seven narrative elements (i.e., selection, probation, escalation, confederation, jeopardy, redemption, and termination). The LMNST contributes to the leadership communication literature a way of viewing leaders' discourse about members through the lens of narrative logics.     

Chinese Women as Transnational Migrants: Gender and Class in Global Migration Narratives

This paper argues that the debates on transnationalism are gender implicit, and the discourse shaped by the emergence of Pacific Asian economies as key players in the global economy sees men as the dominant representative of these global forces. Belief in a real or imagined global bonding has become a dominant and problematic discourse that can empower some, while marginalizing others. It is important to examine how women of Chinese ancestry position themselves within their personal and global environments and to give agency to women in these narratives fashioned by tropes of global capitalism and world markets.
Women now outnumber male immigrants to the major immigration countries of Australia, the United States, and Canada, and this shift is due to the increased migration of women from Asian countries. Yet their position in transmigration and settlement patterns has largely been ignored. This paper argues that the global perspective of Chinese diasporic women has significant implications for both Western and non-Western global patterning. The site of the investigation is Australia in the post 1970s and the focus is on women of Chinese ancestry re-migrating from East and South-East Asia.     

Feddersen and Pesendorfer meet Ellsberg

The Condorcet Jury Theorem formalises the “wisdom of crowds”: binary decisions made by majority vote are asymptotically correct as the number of voters tends to infinity. This classical result assumes like-minded, expected utility maximising voters who all share a common prior belief about the right decision. Ellis (Theor Econo 11(3): 865–895, 2016) shows that when voters have ambiguous prior beliefs—a (closed, convex) set of priors—and follow maxmin expected utility (MEU), such wisdom requires that voters’ beliefs satisfy a “disjoint posteriors” condition: different private signals lead to posterior sets with disjoint interiors. Both the original theorem and Ellis’s generalisation assume symmetric penalties for wrong decisions. If, as in the jury context, errors attract asymmetric penalties then it is natural to consider voting rules that raise the hurdle for the decision carrying the heavier penalty for error (such as conviction in jury trials). In a classical model, Feddersen and Pesendorfer (Am Politi Sci Rev 92(1):23–35, 1998) have shown that, paradoxically, raising this hurdle may actually increase the likelihood of the more serious error. In particular, crowds are not wise under the unanimity rule: the probability of the more serious error does not vanish as the crowd size tends to infinity. We show that this “Jury Paradox” persists in the presence of ambiguity, whether or not juror beliefs satisfy Ellis’s “disjoint posteriors” condition. We also characterise the strictly mixed equilibria of this model and study their properties. Such equilibria cannot exist in the absence of ambiguity but may exist for arbitrarily large jury size when ambiguity is present. In addition to uninformative strictly mixed equilibria, analogous to those exhibited by Ellis (Theor Econo 11(3): 865–895, 2016), there may also exist strictly mixed equilibria which are informative about voter signals.