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251.
Guido Boella Dov M. Gabbay Valerio Genovese Leendert van der Torre 《Studia Logica》2009,92(3):395-436
We study access control policies based on the says operator by introducing a logical framework called Fibred Security Language (FSL) which is able to deal with features like
joint responsibility between sets of principals and to identify them by means of first-order formulas. FSL is based on a multimodal
logic methodology. We first discuss the main contributions from the expressiveness point of view, we give semantics for the
language both for classical and intuitionistic fragment), we then prove that in order to express well-known properties like
‘speaks-for’ or ‘hand-off’, defined in terms of says, we do not need second-order logic (unlike previous approaches) but a decidable fragment of first-order logic suffices. We
propose a model-driven study of the says axiomatization by constraining the Kripke models in order to respect desirable security properties, we study how existing
access control logics can be translated into FSL and we give completeness for the logic. 相似文献
252.
The issue of representing access control requirements continues to demand significant attention. The focus of researchers
has traditionally been on developing particular access control models and policy specification languages for particular applications.
However, this approach has resulted in an unnecessary surfeit of models and languages. In contrast, we describe a general
access control model and a logic-based specification language from which both existing and novel access control models may
be derived as particular cases and from which several approaches can be developed for domain-specific applications. We will
argue that our general framework has a number of specific attractions and an implication of our work is to encourage a methodological
shift from a study of the particulars of access control to its generalities. 相似文献
253.
254.
Two studies investigated whether the importance and valence of a target person's achievement outcome affect (a) the intensity of surprise an observer feels about the actual outcome and (b) the role surprise plays in the motivation of the search for a causal explanation for the target's outcome. The present experiments involved conditions controlling for the confounds among outcome valence, importance, and surprise. Both studies revealed that surprise intensity was affected by outcome valence and importance so that an important negative outcome elicits the highest surprise and unimportant success elicited the second highest surprise. Causal search was strong only after (unexpected) important failures. Results are explained in terms of an extended expectancy-disconfirmation approach. 相似文献
255.
Guido Gainotti 《Neuropsychology review》2017,27(2):134-145
This paper reviews some controversies concerning the original and revised versions of the ‘hub-and-spoke’ model of conceptual representations and their implication for abstraction capacity levels. The ‘hub-and-spoke’ model, which is based on data gathered in patients with semantic dementia (SD), is the most authoritative model of conceptual knowledge. Patterson et al.’s (Nature Reviews Neuroscience, 8(12), 976-987, 2007) classical version of this model maintained that conceptual representations are stored in a unitary ‘amodal’ format in the right and left anterior temporal lobes (ATLs), because in SD the semantic disorder cuts across modalities and categories. Several authors questioned the unitary nature of these representations. They showed that the semantic impairment is ‘multi-modal’only in the advanced stages of SD, when atrophy affects the ATLs bilaterally, but that impariments can be modality-specific in lateralised (early) stages of the disease. In these cases, SD mainly affects lexical-semantic knowledge when atrophy predominates on the left side and pictorial representations when atrophy prevails on the right side. Some aspects of the model (i.e. the importance of spokes, the multimodal format of representations and the graded convergence of modalities within the ATLs), which had already been outlined by Rogers et al. (Psychological Review, 111(1), 205–235, 2004) in a computational model of SD, were strengthened by these results. The relevance of these theoretical problems and of empirical data concerning the neural substrate of concrete and abstract words is discussed critically. The conclusion of the review is that the highest levels of abstraction are due more to the structuring influence of language than to the format of representations. 相似文献
256.
Guido Alessandri Enrico Perinelli Evelina De Longis Valentina Rosa Annalisa Theodorou Laura Borgogni 《Anxiety, stress, and coping》2017,30(6):630-646
Background and objectives: A long research tradition has investigated the impact of stress on university students by assuming that individuals have a limited reservoir of resources, and that negative events and circumstances progressively drain resources thereby producing exhaustion. A recent research tradition, instead, has focused on the detrimental consequences of discrepant levels of implicit (ISE) and explicit (ESE) self-esteem on the development of stress-related symptoms. The present research attempted to merge the aforementioned approaches, with the aim of explaining significant predictors of stress.Design: Within the framework of a Longitudinal Structural Equation Model, we followed a moderated-mediated approach.Method: A sample of university students (N?=?209; 66% females) completed a questionnaire battery including measures of ISE, ESE, perceptions of negative events, and emotional exhaustion. Participants were assessed once a week for eight consecutive weeks.Results: ISE significantly moderated the relationship between ESE and negative events; in turn, the latter significantly predicted emotional exhaustion. Monte Carlo method for assessing mediation showed that negative events significantly mediated the relationship between incongruent self-esteem and emotional exhaustion.Conclusions: The detrimental role of incongruent self-esteem has been corroborated. Practical implications and suggestions for future research dealing with stress in a university setting were provided. 相似文献
257.
Gian Vittorio Caprara Nancy Eisenberg Guido Alessandri 《Journal of Happiness Studies》2017,18(2):353-371
The present study examined in a stringent developmental model whether positivity, conceptualized as a pervasive mode of appraising, viewing, and perceiving life from a positive stance, predicts chronic positive affectivity across time or vice versa. Participants [263 participants (47 % males)], aged 15.5 at the beginning of the study and 23.5 at the end, reported on measures of positivity and dispositional positive affect four times. Longitudinal findings corroborated the posited paths of relations, with positivity significantly predicting positive affectivity across time rather than vice versa. 相似文献
258.
The understanding of the eating disorders (EDs) anorexia (AN) and bulimia nervosa (BN) has undergone remarkable advancements in the past decade. Most studies that have been done in AN show brain gray and white matter volume loss during the ill state that, at least in part, remit with recovery. Similar patterns occur for brain phospholipids assessed using magnet resonance spectroscopy (MRS). Imaging studies have been used to provide functional information regarding serotonin neuroreceptor dynamics, regional cerebral blood flow, or cerebral glucose metabolism. Such studies have implicated cingulate, frontal, temporal, and parietal regions in AN. Investigators have found that challenges such as food and body image distortions may activate some of these regions, raising the possibility that such studies may shed light on puzzling AN symptoms, such as body image distortions or extremes of appetitive behaviors. Emerging data suggest these disturbances persist after recovery from AN, suggesting the possibility that these are traits that may create a vulnerability to develop an ED. While fewer studies have been done in BN or binge eating disorder, there may be disturbances of serotonin metabolism in similar brain regions. Taken together, these findings give promise for future investigations with the hope of delineating brain pathways that contribute to the etiology of EDs 相似文献
259.
The article outlines the studies conducted in Italy on the history of psychology since the 1970s, with particular attention to those elaborated in the 1990s. Reference is made to the institutions, authors, congresses, and other initiatives that in the course of 3 decades have promoted the growth of the history of psychology, and a review is presented of the principal research themes undertaken by scholars. An attempt has been made to identify the principal historiographic tendencies and to illustrate the passage from a sort of "positivistic" historiography to an orientation that could be considered multifactorial or one of complexity, attentive to both the internal and the external components of the scientific enterprise, although with a propensity for the history of ideas. 相似文献
260.
Van Steendam G Dinnyés A Mallet J Meloni R Casabona CR González JG Kure J Szathmáry E Vorstenbosch J Molnár P Edbrooke D Sándor J Oberfrank F Cole-Turner R Hargittai I Littig B Ladikas M Mordini E Roosendaal HE Salvi M Gulyás B Malpede D 《Science and engineering ethics》2006,12(4):731-793
This paper reports on the meeting of the Sounding Board of the EU Reprogenetics Project that was held in Budapest, Hungary, 6-9 November 2005. The Reprogenetics Project runs from 2004 until 2007 and has a brief to study the ethical aspects of human reproductive cloning and germline gene therapy. Discussions during The Budapest Meeting are reported in depth in this paper as well as the initiatives to involve the participating groups and others in ongoing collaborations with the goal of forming an integrated network of European resources in the fields of ethics of science. 相似文献