31,854 research outputs found
Benefits of Location-Based Access Control:A Literature Study
Location-based access control (LBAC) has been suggested as a means to improve IT security. By 'grounding' users and systems to a particular location, \ud
attackers supposedly have more difficulty in compromising a system. However, the motivation behind LBAC and its potential benefits have not been investigated thoroughly. To this end, we perform a structured literature review, and examine the goals that LBAC can potentially fulfill, \ud
the specific LBAC systems that realize these goals and the context on which LBAC depends. Our paper has four main contributions:\ud
first we propose a theoretical framework for LBAC evaluation, based on goals, systems and context. Second, we formulate and apply criteria for evaluating the usefulness of an LBAC system. Third, we identify four usage scenarios for LBAC: open areas and systems, hospitals, enterprises, and finally data centers and military facilities. Fourth, we propose directions for future research:\ud
(i) assessing the tradeoffs between location-based, physical and logical access control, (ii) improving the transparency of LBAC decision making, and \ud
(iii) formulating design criteria for facilities and working environments for optimal LBAC usage
Cyber-Virtual Systems: Simulation, Validation & Visualization
We describe our ongoing work and view on simulation, validation and
visualization of cyber-physical systems in industrial automation during
development, operation and maintenance. System models may represent an existing
physical part - for example an existing robot installation - and a software
simulated part - for example a possible future extension. We call such systems
cyber-virtual systems.
In this paper, we present the existing VITELab infrastructure for
visualization tasks in industrial automation. The new methodology for
simulation and validation motivated in this paper integrates this
infrastructure. We are targeting scenarios, where industrial sites which may be
in remote locations are modeled and visualized from different sites anywhere in
the world.
Complementing the visualization work, here, we are also concentrating on
software modeling challenges related to cyber-virtual systems and simulation,
testing, validation and verification techniques for them. Software models of
industrial sites require behavioural models of the components of the industrial
sites such as models for tools, robots, workpieces and other machinery as well
as communication and sensor facilities. Furthermore, collaboration between
sites is an important goal of our work.Comment: Preprint, 9th International Conference on Evaluation of Novel
Approaches to Software Engineering (ENASE 2014
Geospatial Narratives and their Spatio-Temporal Dynamics: Commonsense Reasoning for High-level Analyses in Geographic Information Systems
The modelling, analysis, and visualisation of dynamic geospatial phenomena
has been identified as a key developmental challenge for next-generation
Geographic Information Systems (GIS). In this context, the envisaged
paradigmatic extensions to contemporary foundational GIS technology raises
fundamental questions concerning the ontological, formal representational, and
(analytical) computational methods that would underlie their spatial
information theoretic underpinnings.
We present the conceptual overview and architecture for the development of
high-level semantic and qualitative analytical capabilities for dynamic
geospatial domains. Building on formal methods in the areas of commonsense
reasoning, qualitative reasoning, spatial and temporal representation and
reasoning, reasoning about actions and change, and computational models of
narrative, we identify concrete theoretical and practical challenges that
accrue in the context of formal reasoning about `space, events, actions, and
change'. With this as a basis, and within the backdrop of an illustrated
scenario involving the spatio-temporal dynamics of urban narratives, we address
specific problems and solutions techniques chiefly involving `qualitative
abstraction', `data integration and spatial consistency', and `practical
geospatial abduction'. From a broad topical viewpoint, we propose that
next-generation dynamic GIS technology demands a transdisciplinary scientific
perspective that brings together Geography, Artificial Intelligence, and
Cognitive Science.
Keywords: artificial intelligence; cognitive systems; human-computer
interaction; geographic information systems; spatio-temporal dynamics;
computational models of narrative; geospatial analysis; geospatial modelling;
ontology; qualitative spatial modelling and reasoning; spatial assistance
systemsComment: ISPRS International Journal of Geo-Information (ISSN 2220-9964);
Special Issue on: Geospatial Monitoring and Modelling of Environmental
Change}. IJGI. Editor: Duccio Rocchini. (pre-print of article in press
Alcohol Availability and Violence: A Closer Look at Space and Time
Alcohol availability plays an important role in violence. Less is known about how spatiotemporal patterns of alcohol–violence association vary across time of day and across various crime types. This study examined whether and how the associations between on- and off-premise alcohol outlets and assaults, and between on- and off-premise alcohol outlets and robberies, vary across different times of day (morning, daytime, evening, and late night). This cross-sectional study used socioeconomic, alcohol license, and crime data from Milwaukee, Wisconsin, aggregated to US Census block groups and estimated spatially lagged maximum likelihood regression models that controlled for spatial dependence. On-premise outlets were negatively associated with evening assaults and positively associated with daytime and late-night robberies. Off-premise outlets were positively associated with evening assaults, late-night assaults, daytime robberies, and evening robberies. Spatiotemporal alcohol–violence associations vary across crime types and across time of day. On- and off-premise alcohol outlets play a unique role across four different temporal categories and across two violent crime types. These findings have the potential to inform theoretical explanations of the alcohol–violence relationship and may be beneficial when considering and designing custom-tailored local alcohol policy to reduce alcohol-related harm
What do we need to add to a social network to get a society? answer: something like what we have to add to a spatial network to get a city
Recent years have seen great advances in social network analysis. Yet, with a few exceptions, the
field of network analysis remains remote from social theory. As a result, much social network
research, while technically accomplished and theoretically suggestive, is essentially descriptive.
How then can social networks be linked to social theory ? Here we pose the question in its simplest
form: what must we add to a social network to get a society ? We begin by showing that one reason
for the disconnection between network theory and society theory is that because it exists in spacetime,
the concept of social network raises the issue of space in a way that is problematical for social
theory. Here we turn the problem on its head and make the problem of space in social network
theory explicit by proposing a surprising analogy with the question: what do you have to add to an
urban space network to get a city. We show first that by treating a city as a naïve spatial network in
the first instance and allowing it to acquire two formal properties we call reflexivity and nonlocality,
both mediated through a mechanism we call description retrieval, we can build a picture of the
dynamics processes by which collections of the buildings become living cities. We then show that
by describing societies initially as social networks in space-time and adding similar properties, we
can construct a plausible ontology of a simple human society
Biological control via "ecological" damping: An approach that attenuates non-target effects
In this work we develop and analyze a mathematical model of biological
control to prevent or attenuate the explosive increase of an invasive species
population in a three-species food chain. We allow for finite time blow-up in
the model as a mathematical construct to mimic the explosive increase in
population, enabling the species to reach "disastrous" levels, in a finite
time. We next propose various controls to drive down the invasive population
growth and, in certain cases, eliminate blow-up. The controls avoid chemical
treatments and/or natural enemy introduction, thus eliminating various
non-target effects associated with such classical methods. We refer to these
new controls as "ecological damping", as their inclusion dampens the invasive
species population growth. Further, we improve prior results on the regularity
and Turing instability of the three-species model that were derived in earlier
work. Lastly, we confirm the existence of spatio-temporal chaos
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