903 research outputs found
Finitely generated free Heyting algebras via Birkhoff duality and coalgebra
Algebras axiomatized entirely by rank 1 axioms are algebras for a functor and
thus the free algebras can be obtained by a direct limit process. Dually, the
final coalgebras can be obtained by an inverse limit process. In order to
explore the limits of this method we look at Heyting algebras which have mixed
rank 0-1 axiomatizations. We will see that Heyting algebras are special in that
they are almost rank 1 axiomatized and can be handled by a slight variant of
the rank 1 coalgebraic methods
A modified BlĂzkaâtype respirometer for the study of swimming metabolism in fishes having deep, laterally compressed bodies or unusual locomotor modes
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73888/1/j.1095-8649.2000.tb00890.x.pd
Reinventing grounded theory: some questions about theory, ground and discovery
Grounded theoryâs popularity persists after three decades of broad-ranging critique. In this article three problematic notions are discussedââtheory,â âgroundâ and âdiscoveryââwhich linger in the continuing use and development of grounded theory procedures. It is argued that far from providing the epistemic security promised by grounded theory, these notionsâembodied in continuing reinventions of grounded theoryâconstrain and distort qualitative inquiry, and that what is contrived is not in fact theory in any meaningful sense, that âgroundâ is a misnomer when talking about interpretation and that what ultimately materializes following grounded theory procedures is less like discovery and more akin to invention. The procedures admittedly provide signposts for qualitative inquirers, but educational researchers should be wary, for the significance of interpretation, narrative and reflection can be undermined in the procedures of grounded theory
Acidithiobacillus thiooxidans secretome containing a newly described lipoprotein Licanantase enhances chalcopyrite bioleaching rate
The nature of the mineralâbacteria interphase where electron and mass transfer processes occur is a key element of the bioleaching processes of sulfide minerals. This interphase is composed of proteins, metabolites, and other compounds embedded in extracellular polymeric substances mainly consisting of sugars and lipids (Gehrke et al., Appl Environ Microbiol 64(7):2743â2747, 1998). On this respect, despite Acidithiobacilliâa ubiquitous bacterial genera in bioleaching processes (Rawlings, Microb Cell Fact 4(1):13, 2005)âhas long been recognized as secreting bacteria (Jones and Starkey, J Bacteriol 82:788â789, 1961; Schaeffer and Umbreit, J Bacteriol 85:492â493, 1963), few studies have been carried out in order to clarify the nature and the role of the secreted protein component: the secretome. This work characterizes for the first time the sulfur (meta)secretome of Acidithiobacillus thiooxidans strain DSM 17318 in pure and mixed cultures with Acidithiobacillus ferrooxidans DSM 16786, identifying the major component of these secreted fractions as a single lipoprotein named here as Licanantase. Bioleaching assays with the addition of Licanantase-enriched concentrated secretome fractions show that this newly found lipoprotein as an active protein additive exerts an increasing effect on chalcopyrite bioleaching rate
Cyber-physical energy systems modeling, test specification, and co-simulation based testing
The gradual deployment of intelligent and coordinated devices in the electrical power system needs careful investigation of the interactions between the various domains involved. Especially due to the coupling between ICT and power systems a holistic approach for testing and validating is required. Taking existing (quasi-) standardised smart grid system and test specification methods as a starting point, we are developing a holistic testing and validation approach that allows a very flexible way of assessing the system level aspects by various types of experiments (including virtual, real, and mixed lab settings). This paper describes the formal holistic test case specification method and applies it to a particular co-simulation experimental setup. The various building blocks of such a simulation (i.e., FMI, mosaik, domain-specific simulation federates) are covered in more detail. The presented method addresses most modeling and specification challenges in cyber-physical energy systems and is extensible for future additions such as uncertainty quantification
Hardware-in-the-loop assessment methods
The importance of using real-time simulation and hardware-in-the-loop techniques for the domain of power and energy systems is covered by this chapter. A brief overview of the main concepts is provided as well as a method for their integration into a holistic validation framework for testing smart grid systems. Also, corresponding reference implementations are outlined
An Integrated Research Infrastructure for Validating Cyber-Physical Energy Systems
Renewables are key enablers in the plight to reduce greenhouse gas emissions
and cope with anthropogenic global warming. The intermittent nature and limited
storage capabilities of renewables culminate in new challenges that power
system operators have to deal with in order to regulate power quality and
ensure security of supply. At the same time, the increased availability of
advanced automation and communication technologies provides new opportunities
for the derivation of intelligent solutions to tackle the challenges. Previous
work has shown various new methods of operating highly interconnected power
grids, and their corresponding components, in a more effective way. As a
consequence of these developments, the traditional power system is being
transformed into a cyber-physical energy system, a smart grid. Previous and
ongoing research have tended to mainly focus on how specific aspects of smart
grids can be validated, but until there exists no integrated approach for the
analysis and evaluation of complex cyber-physical systems configurations. This
paper introduces integrated research infrastructure that provides methods and
tools for validating smart grid systems in a holistic, cyber-physical manner.
The corresponding concepts are currently being developed further in the
European project ERIGrid.Comment: 8th International Conference on Industrial Applications of Holonic
and Multi-Agent Systems (HoloMAS 2017
Rough Sets Determined by Quasiorders
In this paper, the ordered set of rough sets determined by a quasiorder
relation is investigated. We prove that this ordered set is a complete,
completely distributive lattice. We show that on this lattice can be defined
three different kinds of complementation operations, and we describe its
completely join-irreducible elements. We also characterize the case in which
this lattice is a Stone lattice. Our results generalize some results of J.
Pomykala and J. A. Pomykala (1988) and M. Gehrke and E. Walker (1992) in case
is an equivalence.Comment: 18 pages, major revisio
- âŠ