Reify Your Collection Queries for Modularity and Speed!

Modularity and efficiency are often contradicting requirements, such that programers have to trade one for the other. We analyze this dilemma in the context of programs operating on collections. Performance-critical code using collections need often to be hand-optimized, leading to non-modular, brittle, and redundant code. In principle, this dilemma could be avoided by automatic collection-specific optimizations, such as fusion of collection traversals, usage of indexing, or reordering of filters. Unfortunately, it is not obvious how to encode such optimizations in terms of ordinary collection APIs, because the program operating on the collections is not reified and hence cannot be analyzed. We propose SQuOpt, the Scala Query Optimizer--a deep embedding of the Scala collections API that allows such analyses and optimizations to be defined and executed within Scala, without relying on external tools or compiler extensions. SQuOpt provides the same "look and feel" (syntax and static typing guarantees) as the standard collections API. We evaluate SQuOpt by re-implementing several code analyses of the Findbugs tool using SQuOpt, show average speedups of 12x with a maximum of 12800x and hence demonstrate that SQuOpt can reconcile modularity and efficiency in real-world applications.Comment: 20 page

OpenPING: A Reflective Middleware for the Construction of Adaptive Networked Game Applications

The emergence of distributed Virtual Reality (VR) applications that run over the Internet has presented networked game application designers with new challenges. In an environment where the public internet streams multimedia data and is constantly under pressure to deliver over widely heterogeneous user-platforms, there has been a growing need that distributed VR applications be aware of and adapt to frequent variations in their context of execution. In this paper, we argue that in contrast to research efforts targeted at improvement of scalability, persistence and responsiveness capabilities, much less attempts have been aimed at addressing the flexibility, maintainability and extensibility requirements in contemporary distributed VR platforms. We propose the use of structural reflection as an approach that not only addresses these requirements but also offers added value in the form of providing a framework for scalability, persistence and responsiveness that is itself flexible, maintainable and extensible. We also present an adaptive middleware platform implementation called OpenPING1 that supports our proposal in addressing these requirements

Metaphor, Objects, and Commodities

This article is a contribution to a symposium that focuses on the ideas of Margaret Jane Radin as a point of departure, and particularly on her analyses of propertization and commodification. While Radin focuses on the harms associated with commodification of the person, relying on Hegel's idea of alienation, we argue that objectification, and in particular objectification of various features of the digital environment, may have important system benefits. We present an extended critique of Radin's analysis, basing the critique in part on Gadamer's argument that meaning and application are interrelated and that meaning changes with application. Central to this interplay is the speculative form of analysis that seeks to fix meaning, contrasted with metaphorical thought that seeks to undermine some fixed meanings and create new meanings through interpretation. The result is that speculative and metaphorical forms are conjoined in an interactive process through which new adaptations emerge. Taking this critique an additional step, we use examples from contemporary intellectual property law discourse to demonstrate how an interactive approach, grounded in metaphor, can yield important insights

Synthesizing Short-Circuiting Validation of Data Structure Invariants

This paper presents incremental verification-validation, a novel approach for checking rich data structure invariants expressed as separation logic assertions. Incremental verification-validation combines static verification of separation properties with efficient, short-circuiting dynamic validation of arbitrarily rich data constraints. A data structure invariant checker is an inductive predicate in separation logic with an executable interpretation; a short-circuiting checker is an invariant checker that stops checking whenever it detects at run time that an assertion for some sub-structure has been fully proven statically. At a high level, our approach does two things: it statically proves the separation properties of data structure invariants using a static shape analysis in a standard way but then leverages this proof in a novel manner to synthesize short-circuiting dynamic validation of the data properties. As a consequence, we enable dynamic validation to make up for imprecision in sound static analysis while simultaneously leveraging the static verification to make the remaining dynamic validation efficient. We show empirically that short-circuiting can yield asymptotic improvements in dynamic validation, with low overhead over no validation, even in cases where static verification is incomplete

Design for Improving Hospital Stroke Unit Processes: Reducing Complex Systems Failures Leading to Adverse Patient Outcomes

This paper describes recent research involving a user-focused design analysis of in-hospital residential treatment for stroke patients. The focus of the research was to identify positive and negative design heuristics associated with addressing poor performance, errors and failures of patient care associated with current designs of hospital systems processes being inadequate to address actual levels of system complexity. The research findings are based on an in–depth case study following a single patient through a stroke unit in a medium scale hospital of (approximately 280 acute beds overall) with 26 stroke unit beds. The case study involved over 200 hours of observations over nine weeks and liaison with hospital and family over the four months of the patient’s stay in hospital. The findings suggest an explanation for the lack of effective advantage so far shown for integrated care as compared to conventional multidisciplinary care. In essence, they suggest that integrated stroke care and multidisciplinary care are both subject to similar serious systemic organisational failures that in effect reduce outcomes of both to a similar compromised position. The paper concludes with three design heuristics for improving stroke unit outcomes via improving the design of stroke unit organisational systems. These proposed heuristics may be of benefit more widely in hospital system design for improved outcomes. Keywords: Hospital System Design, Design Strategies, User-Based Assessment, Case Study, Viable System Model</p

Educational Technology and Teacher Education: Barriers and Gates in South America

Historically, Educational Technology (EdTech) and Teacher Education (TE) have shared a conflicted relationship, particularly where practicing teachers have not been trained in ET in a manner so that they are able to coherently and efficiently incorporate the new educational technology into their classrooms and schools. In Latin America’s diverse scenario, our analysis is focused on a scenario consisting of Argentina and Uruguay. In this scenario, we identify the social and cultural context where teacher education and teaching practice take place, the EdTech-related programs with the greatest impact, and the “barriers” hindering access to and the application of EdTech, as well as the “bridges” or “gates” that facilitate their effective incorporation to teaching and learning both at schools and in teacher education. Lastly, we propose some courses of action to reduce these barriers and widen the gates connecting EdTech and school settings.Fil: Constantino, Gustavo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Antropología Filosófica y Cultural; Argentin

Communities in university mathematics

This paper concerns communities of learners and teachers that are formed, develop and interact in university mathematics environments through the theoretical lens of Communities of Practice. From this perspective, learning is described as a process of participation and reification in a community in which individuals belong and form their identity through engagement, imagination and alignment. In addition, when inquiry is considered as a fundamental mode of participation, through critical alignment, the community becomes a Community of Inquiry. We discuss these theoretical underpinnings with examples of their application in research in university mathematics education and, in more detail, in two Research Cases which focus on mathematics students' and teachers' perspectives on proof and on engineering students' conceptual understanding of mathematics. The paper concludes with a critical reflection on the theorising of the role of communities in university level teaching and learning and a consideration of ways forward for future research

On Fragments and Geometry: The International Legal Order as Metaphor and How it Matters

This article engages the narrative of fragmentation in international law by asserting that legal academics and professionals have failed to probe more deeply into ‘fragmentation’ as a concept and, more specifically, as a spatial metaphor. The contention here is that however central fragmentation has been to analyses of contemporary international law, this notion has been conceptually assumed, ahistorically accepted and philosophically under-examined. The ‘fragment’ metaphor is tied historically to a cartographic rationality – and thus ‘reality’ – of all social space being reducible to a geometric object and, correspondingly, a planimetric map. The purpose of this article is to generate an appreciation among international lawyers that the problem of ‘fragmentation’ is more deeply rooted in epistemology and conceptual history. This requires an explanation of how the conflation of social space with planimetric reduction came to be constructed historically and used politically, and how that model informs representations of legal practices and perceptions of ‘international legal order’ as an inherently absolute and geometric. This implies the need to dig up and expose background assumptions that have been working to precondition a ‘fragmented’ characterization of worldly space. With the metaphor of ‘digging’ in mind, I draw upon Michel Foucault’s ‘archaeology of knowledge’ and, specifically, his assertion that epochal ideas are grounded by layers of ‘obscure knowledge’ that initially seem unrelated to a discourse. In the case of the fragmentation narrative, I argue obscure but key layers can be found in the Cartesian paradigm of space as a geometric object and the modern States’ imperative to assert (geographic) jurisdiction. To support this claim, I attempt to excavate the fragment metaphor by discussing key developments that led to the production and projection of geometric and planimetric reality since the 16th century