34 resultados para Logic of proofs
em BORIS: Bern Open Repository and Information System - Berna - Suiça
Resumo:
The Logic of Proofs~LP, introduced by Artemov, encodes the same reasoning as the modal logic~S4 using proofs explicitly present in the language. In particular, Artemov showed that three operations on proofs (application~$\cdot$, positive introspection~!, and sum~+) are sufficient to mimic provability concealed in S4~modality. While the first two operations go back to G{\"o}del, the exact role of~+ remained somewhat unclear. In particular, it was not known whether the other two operations are sufficient by themselves. We provide a positive answer to this question under a very weak restriction on the axiomatization of LP.
Resumo:
OBJECT Current data show a favorable outcome in up to 50% of patients with World Federation of Neurosurgical Societies (WFNS) Grade V subarachnoid hemorrhage (SAH) and a rather poor prediction of worst cases. Thus, the usefulness of the current WFNS grading system for identifying the worst scenarios for clinical studies and for making treatment decisions is limited. One reason for this lack of differentiation is the use of "negative" or "silent" diagnostic signs as part of the WFNS Grade V definition. The authors therefore reevaluated the WFNS scale by using "positive" clinical signs and the logic of the Glasgow Coma Scale as a progressive herniation score. METHODS The authors performed a retrospective analysis of 182 patients with SAH who had poor grades on the WFNS scale. Patients were graded according to the original WFNS scale and additionally according to a modified classification, the WFNS herniation (hWFNS) scale (Grade IV, no clinical signs of herniation; Grade V, clinical signs of herniation). The prediction of poor outcome was compared between these two grading systems. RESULTS The positive predictive values of Grade V for poor outcome were 74.3% (OR 3.79, 95% CI 1.94-7.54) for WFNS Grade V and 85.7% (OR 8.27, 95% CI 3.78-19.47) for hWFNS Grade V. With respect to mortality, the positive predictive values were 68.3% (OR 3.9, 95% CI 2.01-7.69) for WFNS Grade V and 77.9% (OR 6.22, 95% CI 3.07-13.14) for hWFNS Grade V. CONCLUSIONS Limiting WFNS Grade V to the positive clinical signs of the Glasgow Coma Scale such as flexion, extension, and pupillary abnormalities instead of including "no motor response" increases the prediction of mortality and poor outcome in patients with severe SAH.
Resumo:
Horizontal coordination, where actors join together to accomplish a common task, has been applauded for its output legitimacy. However, such processes often face challenges due to opposition from local actors who raise concerns about democratic legitimacy and accountability. Moving beyond a logic of effectiveness, we aim to show how and why other forms of legitimacy such as input and throughput dimensions also affect horizontal coordination, in addition to output criteria. Beyond the assumed positive relationship between coordination and effectiveness, we additionally expect horizontal coordination to be (a) impeded by local actors' fear of losing democratic legitimacy; and (b) fostered by accountability in terms of the steering capacity of the state. A comparative case study analysis of water supply structures at the regional level in Switzerland shows, in contrast to our expectation, that effectiveness has mixed impacts on horizontal coordination. Rather than being solely a positive factor for horizontal coordination, certain output criteria such as financial redistribution are found to be a key hindrance. We also find that democratic legitimacy may, indeed, impede horizontal coordination whereas increased accountability positively affects such coordination.
Resumo:
Lipsky’s seminal concept of street-level bureaucrats (SLBs) focuses on their role as public servants. However, in the course of new modes of governance, private actors have gained an additional role as implementation agents. We explore the logic of private SLBs during the implementation of the Swiss Ordinance on Veterinary Medicinal Products (OVMP) where veterinarians are simultaneously implementing agents, policy addressees, and professionals with economic interests. We argue that, because of contradictory reference systems, it is problematic for the output performance if an actor is simultaneously the target group of a policy and its implementing agent.
Resumo:
The liberalization process of the Swiss telecommunications sector follows a logic of ‘autonomous adaptation’ to the regulations of the European Union (EU). Switzerland, which is not a Member State of the EU, voluntarily adapts to the European policy without being for- mally required to do so (Sciarini et al., 2004). This process went hand in hand with the partial privatization of the legal statute and assets of the former monopolist and with the re-regulation of the liberalized telecommunications sector.
Resumo:
In this article, we introduce the probabilistic justification logic PJ, a logic in which we can reason about the probability of justification statements. We present its syntax and semantics, and establish a strong completeness theorem. Moreover, we investigate the relationship between PJ and the logic of uncertain justifications.
Resumo:
Clinicians believe that psychosocial factors play a causal role in the etiology of many forms of functional dysphonia (FD). But for decades, all attempts to confirm such causation have failed. This paper aims to show the logic of this failure, to discuss the possibilities of employing psychology in therapy nonetheless, and to encourage clinicians to use their psychosocial knowledge and skills. The failure to confirm psychic and social factors as causal in the etiology of FD is basically a consequence of a principal shortcoming of evidence-based medicine (EBM). As the gold standard for validity, reliability, and objectivity in medical research, EBM is based on calculability and hence the processing of quantitative data. But life paths and life situations are best or sometimes only expressible in qualitative, experiential, and idiographic terms. Thus EBM-guided evaluation undervalues most psychosocial studies. This report of an experienced multidisciplinary voice team proposes alternative pathways for integrating psychosocial knowledge into the diagnosis and the treatment of FD. The difference between the fields of activity of psychotherapists and speech-language pathologists is discussed, and the latter group is shown the potential benefits of using more of their psychosocial knowledge and skills.
Resumo:
Justification Logic is a framework for reasoning about evidence and justification. Public Announcement Logic is a framework for reasoning about belief changes caused by public announcements. This paper develops JPAL, a dynamic justification logic of public announcements that corresponds to the modal theory of public announcements due to Gerbrandy and Groeneveld. JPAL allows us to reason about evidence brought about by and changed by Gerbrandy--Groeneveld-style public announcements.
Resumo:
It is not clear what a system for evidence-based common knowledge should look like if common knowledge is treated as a greatest fixed point. This paper is a preliminary step towards such a system. We argue that the standard induction rule is not well suited to axiomatize evidence-based common knowledge. As an alternative, we study two different deductive systems for the logic of common knowledge. The first system makes use of an induction axiom whereas the second one is based on co-inductive proof theory. We show the soundness and completeness for both systems.
Resumo:
Gaining economic benefits from substantially lower labor costs has been reported as a major reason for offshoring labor-intensive information systems services to low-wage countries. However, if wage differences are so high, why is there such a high level of variation in the economic success between offshored IS projects? This study argues that offshore outsourcing involves a number of extra costs for the ^his paper was recommended for acceptance by Associate Guest Editor Erran Carmel. client organization that account for the economic failure of offshore projects. The objective is to disaggregate these extra costs into their constituent parts and to explain why they differ between offshored software projects. The focus is on software development and maintenance projects that are offshored to Indian vendors. A theoretical framework is developed a priori based on transaction cost economics (TCE) and the knowledge-based view of the firm, comple mented by factors that acknowledge the specific offshore context The framework is empirically explored using a multiple case study design including six offshored software projects in a large German financial service institution. The results of our analysis indicate that the client incurs post contractual extra costs for four types of activities: (1) re quirements specification and design, (2) knowledge transfer, (3) control, and (4) coordination. In projects that require a high level of client-specific knowledge about idiosyncratic business processes and software systems, these extra costs were found to be substantially higher than in projects where more general knowledge was needed. Notably, these costs most often arose independently from the threat of oppor tunistic behavior, challenging the predominant TCE logic of market failure. Rather, the client extra costs were parti cularly high in client-specific projects because the effort for managing the consequences of the knowledge asymmetries between client and vendor was particularly high in these projects. Prior experiences of the vendor with related client projects were found to reduce the level of extra costs but could not fully offset the increase in extra costs in highly client-specific projects. Moreover, cultural and geographic distance between client and vendor as well as personnel turnover were found to increase client extra costs. Slight evidence was found, however, that the cost-increasing impact of these factors was also leveraged in projects with a high level of required client-specific knowledge (moderator effect).