Robust active representation via ℓ2,p-norm constraints

2021 ◽  
pp. 107639
Author(s):  
Jiaoyan Zhao ◽  
Shuangyan Yi ◽  
Yongsheng Liang ◽  
Wei Liu ◽  
Xiaofeng Cao
2021 ◽  
Vol 4 ◽  
Author(s):  
Vasileios Ioakeimidis ◽  
Nareg Khachatoorian ◽  
Corinna Haenschel ◽  
Thomas A. Papathomas ◽  
Attila Farkas ◽  
...  

Abstract The hollow-mask illusion is an optical illusion where a concave face is perceived as convex. It has been demonstrated that individuals with schizophrenia and anxiety are less susceptible to the illusion than controls. Previous research has shown that the P300 and P600 event-related potentials (ERPs) are affected in individuals with schizophrenia. Here, we examined whether individual differences in neuroticism and anxiety scores, traits that have been suggested to be risk factors for schizophrenia and anxiety disorders, affect ERPs of healthy participants while they view concave faces. Our results confirm that the participants were susceptible to the illusion, misperceiving concave faces as convex. We additionally demonstrate significant interactions of the concave condition with state anxiety in central and parietal electrodes for P300 and parietal areas for P600, but not with neuroticism and trait anxiety. The state anxiety interactions were driven by low-state anxiety participants showing lower amplitudes for concave faces compared to convex. The P300 and P600 amplitudes were smaller when a concave face activated a convex face memory representation, since the stimulus did not match the active representation. The opposite pattern was evident in high-state anxiety participants in regard to state anxiety interaction and the hollow-mask illusion, demonstrating larger P300 and P600 amplitudes to concave faces suggesting impaired late information processing in this group. This could be explained by impaired allocation of attentional resources in high-state anxiety leading to hyperarousal to concave faces that are unexpected mismatches to standard memory representations, as opposed to expected convex faces.


Author(s):  
Christian Merkel ◽  
Mandy Viktoria Bartsch ◽  
Mircea A Schoenfeld ◽  
Anne-Katrin Vellage ◽  
Notger G Müller ◽  
...  

Visual working memory (VWM) is an active representation enabling the manipulation of item information even in the absence of visual input. A common way to investigate VWM is to analyze the performance at later recall. This approach, however, leaves uncertainties about whether the variation of recall performance is attributable to item encoding and maintenance or to the testing of memorized information. Here, we record the contralateral delay activity (CDA) - an established electrophysiological measure of item storage and maintenance - in human subjects performing a delayed orientation precision estimation task. This allows us to link the fluctuation of recall precision directly to the process of item encoding and maintenance. We show that for two sequentially encoded orientation items, the CDA amplitude reflects the precision of orientation recall of both items, with higher precision being associated with a larger amplitude. Furthermore, we show that the CDA amplitude for each item varies independently from each other, suggesting that the precision of memory representations fluctuates independently.


2016 ◽  
Author(s):  
◽  
Elijah Agyapong

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Over the years, scholars have examined representative bureaucracy as a viable means to achieve bureaucratic responsiveness in a democratic society. The theory argues that a diverse public service that mirrors the social demographics of its population in terms of gender, race, and ethnicity (passive representation) is more likely to be responsive to the needs of all citizens (active representation). While a substantial amount of empirical research exists, a comparative understanding of the theory is lacking in Africa. This study expands empirical research on the theory to Ghana, one of the successful democracies in Sub-Saharan Africa, and focuses specifically on female representation in education. The study accomplishes two primary objectives. First, it investigates whether passive representation of female teachers and school administrators would make the education bureaucracy more responsive to girls' education in Ghana. Second, it seeks to understand the mechanisms by which passive representation translates into active representation for female students in the Ghanaian context. The analysis of an administrative dataset on senior high schools within the 216 districts of Ghana revealed that passive representation of female teachers was positively associated with the performance of girls on math and science exit exams. More female students passed the math and science exams in districts that employed more female teachers. The relationship was statistically significant after controlling for other theoretically relevant factors. In order to better understand how passive representation leads to substantive benefits for female students, a comprehensive model was examined which incorporated social backgrounds, attitudes/role acceptance, and active representation. The model hypothesized that a teacher can assume the role of an advocate or a representative of girls' interests. Those who adopt the advocacy role, regardless of their social identities, will be more likely to make decisions or take actions that improve educational outcomes for female students. A random sample of 200 teachers in eight senior high schools within the Accra Metropolis of Ghana was surveyed about their attitudes toward girls' education. In addition, school superintendents and officials in the Ghana Education Service were interviewed to provide qualitative insights. The findings indicated that gender and perceived expectation from various stakeholders influenced the extent to which teachers perceived their roles as advocates of girls. Organizational socialization and the acceptance of impartial bureaucratic roles did not overwhelm the influence of gender and perceived role expectations on the advocacy role. However, adoption of the advocacy role rather than gender predicted the potential for active representation, measured as a teacher's self-reported behavior in terms of actively taking actions to address the educational needs of girls. The findings from this sample lend considerable support for the relationship between role perceptions and the potential for active representation. It suggests that the advocacy role mediates the relationship between passive and active representation. This study therefore provides a better understanding of how a representative bureaucracy can engender responsiveness to women's education in Ghana and the Sub-Saharan African region.


1999 ◽  
Vol 22 (2) ◽  
pp. 297-298
Author(s):  
R. Miller

Empirical evidence suggests that high frequency electrographic activity is involved in active representation of meaningful entities in the cortex. Theoretical work suggests that distributed cell assemblies also represent meaningful entities. However, we are still some way from understanding how these two are related. This commentary also makes suggestions for further investigation of the neural basis of language at the level of both words and sentence planning.


1996 ◽  
Vol 6 (4) ◽  
pp. 612-619 ◽  
Author(s):  
S. C. Baker ◽  
C. D. Frith ◽  
S. J. Frackowiak ◽  
R. J. Dolan

2002 ◽  
Vol 96 (3) ◽  
pp. 553-564 ◽  
Author(s):  
LAEL R. KEISER ◽  
VICKY M. WILKINS ◽  
KENNETH J. MEIER ◽  
CATHERINE A. HOLLAND

According to the theory of representative bureaucracy, passive representation among public employees will lead to active representation in bureaucratic outputs. Existing research demonstrates that the link between passive and active representation exists for race but not for sex. Past research on this topic has not, however, taken into account the contextual environment that affects whether sex will translate into gender and lead to active representation in the bureaucracy. In this paper, we create a framework that specifies the conditions that affect whether passive representation results in active representation for sex and then test this framework using the case of education. We find that passive representation of women in education leads to active representation and that the institutional context affects the extent to which this link between passive and active representation occurs.


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