1,807 research outputs found
["In der Jungfernheide hinterm Pulvermagazin frequens"].
Journal ArticleWe provide a detailed description of an interleaved and heavily annotated copy of Florae Berolinensis Prodromus, a flora of Berlin published by the German apothecary and botanist Karl Ludwig Willdenow in 1787, which today is preserved at the Staatsbibliothek zu Berlin – Preußischer Kulturbesitz. We demonstrate that this is the copy that the author himself used and carried with him during his botanical excursions in and around Berlin to prepare a second edition of the work. By analyzing this document as paper technology, we reveal that even seemingly trifling aspects of its material organization enabled far-reaching biological research agendas that were not originally intended. The hybrid form of manuscript and printed book, used in field excursions, enabled a kind of natural-historical observation that was at once detailed and bound by strict (Linnaean) convention, a combination that inadvertently opened new research questions and suggested new objects of research. We thereby contribute to an understanding of the history of natural history that goes beyond the history of ideas and the intended uses of techniques, giving an example of how routine work on paper within a scientific tradition could generate innovation
The economics of mandatory security breach reporting to authorities
Legislators in many countries enact security breach notification regulation to address a lack of information security. The laws designate authorities to collect breach reports and advise firms. We devise a principal–agent model to analyze the economic effect of mandatory security breach reporting to authorities. The model assumes that firms (agents) have few incentives to unilaterally report breaches. To enforce the law, regulators (principals) can introduce security audits and sanction noncompliance. However, audits cannot differentiate between concealment and nescience of the agents. Even under optimistic assumptions regarding the effectiveness of mandatory security breach reporting to authorities in reducing individual losses, our model predicts that it may be difficult to adjust the sanction level such that breach notification laws generate social benefit
Encoding monomorphic and polymorphic types
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 un-typed 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 polymorphism 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 formalized the monomorphic part of this work in Isabelle/HOL. Our evaluation finds the new encodings vastly superior to previous schemes
Encoding monomorphic and polymorphic types
Most 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. 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 polymorphism and present alternative schemes that lighten
the translation of polymorphic symbols based on the novel notion of “cover”. The new encodings are implemented, and partly proved correct, in Isabelle/HOL. Our evaluation finds them vastly superior to previous schemes
A Proof Strategy Language and Proof Script Generation for Isabelle/HOL
We introduce a language, PSL, designed to capture high level proof strategies
in Isabelle/HOL. Given a strategy and a proof obligation, PSL's runtime system
generates and combines various tactics to explore a large search space with low
memory usage. Upon success, PSL generates an efficient proof script, which
bypasses a large part of the proof search. We also present PSL's monadic
interpreter to show that the underlying idea of PSL is transferable to other
ITPs.Comment: This paper has been submitted to CADE2
XWeB: the XML Warehouse Benchmark
With the emergence of XML as a standard for representing business data, new
decision support applications are being developed. These XML data warehouses
aim at supporting On-Line Analytical Processing (OLAP) operations that
manipulate irregular XML data. To ensure feasibility of these new tools,
important performance issues must be addressed. Performance is customarily
assessed with the help of benchmarks. However, decision support benchmarks do
not currently support XML features. In this paper, we introduce the XML
Warehouse Benchmark (XWeB), which aims at filling this gap. XWeB derives from
the relational decision support benchmark TPC-H. It is mainly composed of a
test data warehouse that is based on a unified reference model for XML
warehouses and that features XML-specific structures, and its associate XQuery
decision support workload. XWeB's usage is illustrated by experiments on
several XML database management systems
Mindfulness Training at School: A Way to Engage Adolescents with Sustainable Consumption?
A central challenge in research on education for sustainable consumption (ESC) is to develop new approaches to engage adolescents with sustainable consumption (SC) in a way that addresses not only the cognitive but also the socio-emotional and behavioral levels. Mindfulness-based interventions (MBIs) that foster awareness, (self-)reflection, and ethical values could potentially leverage learning processes in ESC. The present study was the first one to investigate the potential effects of a consumption-specific MBI on sustainable consumption behavior (SCB) in the areas of nutrition and clothing. The eight-week long intervention was carried out with 15-year old adolescents (N = 85) directly at school. A randomized pre-post waitlist control group design with mixed methods was applied. The study revealed the strong effects of the adapted MBI on precursors of SCB and further effects not directly related to but potentially conducive for SCB. Actual behavioral effects were minor. Substantial inter-individual differences and inconsistencies between qualitative and quantitative results imply case-related effects that do not allow generalizable conclusions to be drawn. Nevertheless, the results of this pilot study indicate that combining mindfulness training with ESC formats appears to be a feasible and fruitful approach to engage adolescents with SC. Future practice and research should consider more diverse target groups, other consumption areas, and longer periods for interventions and their evaluation.BMBF, 01UT1416A, Bildung für Nachhaltigen Konsum durch Achtsamkeitstraining - Teilprojekt 1 der TU Berlin: Achtsamkeitsforschung und Nachhaltiger KonsumBMBF, 01UT1416B, Bildung für Nachhaltigen Konsum durch Achtsamkeitstraining - Teilprojekt 2 der Leuphana Universität Lüneburg: Bildung für Nachhaltigen Konsu
Desynchronization and Wave Pattern Formation in MPI-Parallel and Hybrid Memory-Bound Programs
Analytic, first-principles performance modeling of distributed-memory
parallel codes is notoriously imprecise. Even for applications with extremely
regular and homogeneous compute-communicate phases, simply adding communication
time to computation time does often not yield a satisfactory prediction of
parallel runtime due to deviations from the expected simple lockstep pattern
caused by system noise, variations in communication time, and inherent load
imbalance. In this paper, we highlight the specific cases of provoked and
spontaneous desynchronization of memory-bound, bulk-synchronous pure MPI and
hybrid MPI+OpenMP programs. Using simple microbenchmarks we observe that
although desynchronization can introduce increased waiting time per process, it
does not necessarily cause lower resource utilization but can lead to an
increase in available bandwidth per core. In case of significant communication
overhead, even natural noise can shove the system into a state of automatic
overlap of communication and computation, improving the overall time to
solution. The saturation point, i.e., the number of processes per memory domain
required to achieve full memory bandwidth, is pivotal in the dynamics of this
process and the emerging stable wave pattern. We also demonstrate how hybrid
MPI-OpenMP programming can prevent desirable desynchronization by eliminating
the bandwidth bottleneck among processes. A Chebyshev filter diagonalization
application is used to demonstrate some of the observed effects in a realistic
setting.Comment: 18 pages, 8 figure
A Human-Oriented Term Rewriting System
© Springer Nature Switzerland AG 2019. We introduce a fully automatic system, implemented in the Lean theorem prover, that solves equality problems of everyday mathematics. Our overriding priority in devising the system is that it should construct proofs of equality in a way that is similar to that of humans. A second goal is that the methods it uses should be domain independent. The basic strategy of the system is to operate with a subtask stack: whenever there is no clear way of making progress towards the task at the top of the stack, the program finds a promising subtask, such as rewriting a subterm, and places that at the top of the stack instead. Heuristics guide the choice of promising subtasks and the rewriting process. This makes proofs more human-like by breaking the problem into tasks in the way that a human would. We show that our system can prove equality theorems simply, without having to preselect or orient rewrite rules as in standard theorem provers, and without having to invoke heavy duty tools for performing simple reasoning
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