121,849 research outputs found

    Combinations of Qualitative Winning for Stochastic Parity Games

    No full text
    We study Markov decision processes and turn-based stochastic games with parity conditions. There are three qualitative winning criteria, namely, sure winning, which requires all paths to satisfy the condition, almost-sure winning, which requires the condition to be satisfied with probability 1, and limit-sure winning, which requires the condition to be satisfied with probability arbitrarily close to 1. We study the combination of two of these criteria for parity conditions, e.g., there are two parity conditions one of which must be won surely, and the other almost-surely. The problem has been studied recently by Berthon et al. for MDPs with combination of sure and almost-sure winning, under infinite-memory strategies, and the problem has been established to be in NP cap co-NP. Even in MDPs there is a difference between finite-memory and infinite-memory strategies. Our main results for combination of sure and almost-sure winning are as follows: (a) we show that for MDPs with finite-memory strategies the problem is in NP cap co-NP; (b) we show that for turn-based stochastic games the problem is co-NP-complete, both for finite-memory and infinite-memory strategies; and (c) we present algorithmic results for the finite-memory case, both for MDPs and turn-based stochastic games, by reduction to non-stochastic parity games. In addition we show that all the above complexity results also carry over to combination of sure and limit-sure winning, and results for all other combinations can be derived from existing results in the literature. Thus we present a complete picture for the study of combinations of two qualitative winning criteria for parity conditions in MDPs and turn-based stochastic games

    Faster and Smaller Solutions of Obliging Games

    No full text
    Obliging games have been introduced in the context of the game perspective on reactive synthesis in order to enforce a degree of cooperation between the to-be-synthesized system and the environment. Previous approaches to the analysis of obliging games have been small-step in the sense that they have been based on a reduction to standard (non-obliging) games in which single moves correspond to single moves in the original (obliging) game. Here, we propose a novel, large-step view on obliging games, reducing them to standard games in which single moves encode long-term behaviors in the original game. This not only allows us to give a meaningful definition of the environment winning in obliging games, but also leads to significantly improved bounds on both strategy sizes and the solution runtime for obliging games

    A Multi-Language Comparison of Influences on Author Verification using Character N-Grams

    No full text
    We create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc

    Appropriate Similarity Measures for Author Cocitation Analysis

    No full text
    We provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis

    An overview of the mCRL2 toolset and its recent advances

    No full text
    The analysis of complex distributed systems requires dedicated software tools. The mCRL language and toolset have been developed to support such analysis. We highlight changes and improvements made to the toolset in recent years. On the one hand, these affect the scope of application, which has been broadened with extended support for data structures like infinite sets and functions. On the other hand, considerable progress has been made regarding the performance of our tools for state space generation and model checking, due to improvements in symbolic reduction techniques and due to a shift towards parity game-based solving. We also discuss the software architecture of the toolset, which was well suited to accommodate the above changes, and we address a number of case studies to illustrate the approach

    The vanishing author in computer-generated works: a critical analysis of recent Australian case law

    No full text
    Abstract The use of software is ubiquitous in the creation of many copyright works, yet the requirement in copyright law that every work have a human author who engages in independent intellectual effort means that its use may prevent copyright subsistence. Several recent Australian cases have refocused attention on authorship as an essential criterion of copyright subsistence, and these cases suggest that much computer-produced output may be authorless and thus lack copyright protection. This article, the first in a two-part series, analyses how each case deals with the question of authorship of computer-produced works and why the use of software diminishes copyright protection for a significant number of computer-generated works. The article critiques the application of conventional notions of human authorship developed in the pre-computer age to modern productions and suggests alternative approaches to authorship that satisfy both the major objectives of copyright policy and the need to adapt to the computer age. The article argues that, without a broader judicial approach to authorship of computer-generated works, Parliament must remedy the lacuna in protection for these ‘authorless’ works. Possible solutions for reform are suggested. In a forthcoming article, the author comprehensively examines those reform proposals

    Diffusive author(s), cohesive author: Analysis of S/N (1994)

    No full text
    This study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)

    The evolution of nursing in Australian general practice: a comparative analysis of workforce surveys ten years on

    No full text
    This article describes the current demographic and employment characteristics of Australian nurses working in general practice, and explores trends in their role over time. Abstract: Background Nursing in Australian general practice has grown rapidly over the last decade in response to government initiatives to strengthen primary care. There are limited data about how this expansion has impacted on the nursing role, scope of practice and workforce characteristics. This study aimed to describe the current demographic and employment characteristics of Australian nurses working in general practice and explore trends in their role over time. Methods In the nascence of the expansion of the role of nurses in Australian general practice (2003–2004) a national survey was undertaken to describe nurse demographics, clinical roles and competencies. This survey was repeated in 2009–2010 and comparative analysis of the datasets undertaken to explore workforce changes over time. Results Two hundred eighty four nurses employed in general practice completed the first survey (2003/04) and 235 completed the second survey (2009/10). Significantly more participants in Study 2 were undertaking follow-up of pathology results, physical assessment and disease specific health education. There was also a statistically significant increase in the participants who felt that further education/training would augment their confidence in all clinical tasks (p < 0.001). Whilst the impact of legal implications as a barrier to the nurses’ role in general practice decreased between the two time points, more participants perceived lack of space, job descriptions, confidence to negotiate with general practitioners and personal desire to enhance their role as barriers. Access to education and training as a facilitator to nursing role expansion increased between the two studies. The level of optimism of participants for the future of the nurses’ role in general practice was slightly decreased over time. Conclusions This study has identified that some of the structural barriers to nursing in Australian general practice have been addressed over time. However, it also identifies continuing barriers that impact practice nurse role development. Understanding and addressing these issues is vital to optimise the effectiveness of the primary care nursing workforce

    Encoding Monomorphic and Polymorphic Types

    No full text
    Many automatic theorem provers are restricted to untyped logics, and existing translations from typed logics are bulky or unsound. Recent research proposes monotonicity as a means to remove some clutter when translating monomorphic to untyped first-order logic. Here we pursue this approach systematically, analysing formally a variety of encodings that further improve on efficiency while retaining soundness and completeness. We extend the approach to rank-1 po lymorphism and present alternative schemes that lighten the translation of polymorphic symbols based on the novel notion of “cover”. The new encodings are implemented in Isabelle/HOL as part of the Sledgehammer tool. We include informal proofs of soundness and correctness, and have formalised the monomorphic part of this work in Isabelle/HOL. Our evaluation finds the new encodings vastly superior to previous schemes

    Equivalence checking of quantum protocols

    No full text
    Quantum Information Processing (QIP) is an emerging area at the intersection of physics and computer science. It aims to establish the principles of communication and computation for systems based on the theory of quantum mechanics. Interesting QIP protocols such as quantum key distribution, teleportation, and blind quantum computation have already been realised in the laboratory and are now in the realm of mainstream industrial applications. The complexity of these protocols, along with possible inaccuracies in implementation, demands systematic and formal analysis. In this paper, we present a new technique and a tool, with a high-level interface, for verification of quantum protocols using equivalence checking. Previous work by Gay, Nagarajan and Papanikolaou used model-checking to verify quantum protocols represented in the stabilizer formalism, a restricted model which can be simulated efficiently on classical computers. Here, we are able to go beyond stabilizer states and verify protocols efficiently on all input states
    corecore