Separation of Reliability and Secrecy in Rate-Limited Secret-Key Generation

For a discrete or a continuous source model, we study the problem of secret-key generation with one round of rate-limited public communication between two legitimate users. Although we do not provide new bounds on the wiretap secret-key (WSK) capacity for the discrete source model, we use an alternative achievability scheme that may be useful for practical applications. As a side result, we conveniently extend known bounds to the case of a continuous source model. Specifically, we consider a sequential key-generation strategy, that implements a rate-limited reconciliation step to handle reliability, followed by a privacy amplification step performed with extractors to handle secrecy. We prove that such a sequential strategy achieves the best known bounds for the rate-limited WSK capacity (under the assumption of degraded sources in the case of two-way communication). However, we show that, unlike the case of rate-unlimited public communication, achieving the reconciliation capacity in a sequential strategy does not necessarily lead to achieving the best known bounds for the WSK capacity. Consequently, reliability and secrecy can be treated successively but not independently, thereby exhibiting a limitation of sequential strategies for rate-limited public communication. Nevertheless, we provide scenarios for which reliability and secrecy can be treated successively and independently, such as the two-way rate-limited SK capacity, the one-way rate-limited WSK capacity for degraded binary symmetric sources, and the one-way rate-limited WSK capacity for Gaussian degraded sources.Comment: 18 pages, two-column, 9 figures, accepted to IEEE Transactions on Information Theory; corrected typos; updated references; minor change in titl

Suspicious Spirits, Flexible Minds: When Distrust Enhances Creativity

Considering that distrust is a core element of human interaction, it has received surprisingly little scientific attention. This research contributes to filling this gap by investigating distrust’s influence on creativity. Intuitively as well as in light of prior research, distrust and creativity appear incompatible. The social consequences of distrust include reluctance to share information, a quality detrimental to creativity in social settings. At the same time, the cognitive concomitants of distrust bear resemblance to creative cognition: Distrust seems to foster thinking about non-obvious alternatives to potentially deceptive appearances. This tendency resembles cognitive flexibility, which is conducive to creativity. These cognitive underpinnings of distrust hold the provocative implication that distrust may foster creativity. Mirroring these contradictory findings, I suggest that the social vs. cognitive consequences of distrust have diverging implications for creativity. I address this question in Study 1 by introducing private/public as a moderating variable for effects of distrust on creativity. Consistent with distrust’s social consequences, subliminal distrust (vs. trust) priming had detrimental effects on creative generation presumed to be public. Consistent with distrust’s cognitive consequences, though, the opposite emerged in private. Study 2 replicated a beneficial effect of distrust on private creative generation with a different priming method. Studies 3 and 4 showed increased category inclusiveness vs. increased remote semantic spread after distrust priming. The latter findings are consistent with enhanced cognitive flexibility as a consequence of distrust. Taken together, these results provide evidence for the creativity-enhancing potential of distrust and suggest cognitive flexibility as the process in question

Explaining Levels of Customer Satisfaction with First Contact with Jobcentre Plus: results of qualitative research with Jobcentre Plus Staff

This report is a follow up to the First Contact Customer Survey (Research Report 504). As a result of ongoing difficulties accessing data for sampling purposes, the initial plan to undertake qualitative follow-up research with customers was abandoned in favour of research with staff to explore process-related issues which might explain customer responses. The research was undertaken in September and October 2008 and included telephone interviews with senior staff combined with face-to-face interviews and structured observations with staff in Contact Centres, Jobcentres and Benefit Delivery Centres in four Jobcentre Plus regions. Findings relate specifically to staff perceptions of customer satisfaction with first contact

Taking Politics at Face Value: How Features Expose Ideology

Previous studies using computer vision neural networks to analyze facial images have uncovered patterns in the feature extracted output that are indicative of individual dispositions. For example, Wang and Kosinski (2018) were able to predict the sexual orientation of a target from his or her facial image with surprising accuracy, while Kosinski (2021) was able to do the same in regards to political orientation. These studies suggest that computer vision neural networks can be used to classify people into categories using only their facial images.However, there is some ambiguity in regards to the degree to which these features extracted from facial images incorporate facial morphology when used to make predictions. Critics have suggested that a subject’s transient facial features, such as using makeup, having a tan, donning a beard, or wearing glasses, might be subtly indicative of group belonging (Agüera y Arcas et al., 2018). Further, previous research in this domain has found that accurate image categorization can occur without utilizing facial morphology at all, instead relying upon image brightness, color dominance, or the background of the image to make successful classifications (Leuner, 2019; Wang, 2022). This dissertation seeks to bring some clarity to this domain. Using an application programming interface (API) for the popular social networking site Twitter, a sample of nearly a quarter million images of ideological organization followers was created. These images were followers of organizations supportive of, or oppositional to, the polarizing political issues of gun control and immigration. Through a series of strong comparisons, this research tests for the influence of facial morphology in image categorization. Facial images were converted into point and mesh coordinate representations of the subjects’ faces, thus eliminating the influence of transient facial features. Images were able to be classified using facial morphology alone at rates well above chance (64% accuracy across all models utilizing only facial points, 62% using facial mesh). These results provide the strongest evidence to date that images can be categorized into social categories by their facial morphology alone