44,381 research outputs found
On Small Satellites for Oceanography: A Survey
The recent explosive growth of small satellite operations driven primarily
from an academic or pedagogical need, has demonstrated the viability of
commercial-off-the-shelf technologies in space. They have also leveraged and
shown the need for development of compatible sensors primarily aimed for Earth
observation tasks including monitoring terrestrial domains, communications and
engineering tests. However, one domain that these platforms have not yet made
substantial inroads into, is in the ocean sciences. Remote sensing has long
been within the repertoire of tools for oceanographers to study dynamic large
scale physical phenomena, such as gyres and fronts, bio-geochemical process
transport, primary productivity and process studies in the coastal ocean. We
argue that the time has come for micro and nano satellites (with mass smaller
than 100 kg and 2 to 3 year development times) designed, built, tested and
flown by academic departments, for coordinated observations with robotic assets
in situ. We do so primarily by surveying SmallSat missions oriented towards
ocean observations in the recent past, and in doing so, we update the current
knowledge about what is feasible in the rapidly evolving field of platforms and
sensors for this domain. We conclude by proposing a set of candidate ocean
observing missions with an emphasis on radar-based observations, with a focus
on Synthetic Aperture Radar.Comment: 63 pages, 4 figures, 8 table
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Towards a business model for cellular network and telecommunication operators: a theoretical framework
Cellular networks and telecommunications bring major change to the way businesses are conducted.
Mobility has become one of the main priorities for users and this has impacted on cellular networks and telecommunication operators (CNTOs). However, entrants into the cellular industry have been confounded primarily by inexistent or weak Business Models (BMs). Designing a BM for a CNTO is
complex and requires multiple actors to balance different and often conflicting design requirements. Nevertheless, most research about CNTOs has been technically oriented and has mainly addressed the technological and engineering issues related to their infrastructure. Less attention has been given to
the business model of CNTOs. Hence, there is a need to enhance our ability to determine what
constitutes the optimal and most viable business model to meet the various strategic objectives and
goals for these CNTOs. In this paper an overview of research into the cellular business model and the main issues to be resolved is provided. In particular, the authors propose guidelines as a basis on which to develop a more comprehensive definition which may lead to a consensus. Moreover, a generic model (V4 Model) is proposed for the BM of these companies based on value proposition, value architecture, value network and value finance
Space program: Space debris a potential threat to Space Station and shuttle
Experts estimate that more than 3.5 million man-made objects are orbiting the earth. These objects - space debris - include whole and fragmentary parts of rocket bodies and other discarded equipment from space missions. About 24,500 of these objects are 1 centimeter across or larger. A 1-centimeter man-made object travels in orbit at roughly 22,000 miles per hour. If it hit a spacecraft, it would do about the same damage as would a 400-pound safe traveling at 60 miles per hour. The Government Accounting Office (GAO) reviews NASA's plans for protecting the space station from debris, the extent and precision of current NASA and Defense Department (DOD) debris-tracking capabilities, and the extent to which debris has already affected shuttle operations. GAO recommends that the space debris model be updated, and that the findings be incorporated into the plans for protecting the space station from such debris. GAO further recommends that the increased risk from debris to the space shuttle operations be analyzed
A2THOS: Availability Analysis and Optimisation in SLAs
IT service availability is at the core of customer satisfaction and business success for todayâs organisations. Many medium-large size organisations outsource part of their IT services to external providers, with Service Level Agreements describing the agreed availability of outsourced service components. Availability management of partially outsourced IT services is a non trivial task since classic approaches for calculating availability are not applicable, and IT managers can only rely on their expertise to fulfil it. This often leads to the adoption of non optimal solutions. In this paper we present A2THOS, a framework to calculate the availability of partially outsourced IT services in the presence of SLAs and to achieve a cost-optimal choice of availability levels for outsourced IT components while guaranteeing a target availability level for the service
The future of UAS: standards, regulations, and operational experiences [workshop report]
This paper presents the outcomes of "The Future of UAS: Standards, Regulations and Operational Experiences" workshop, held on the 7th and 8th of December, 2006 in Brisbane, Queensland, Australia. The goal of the workshop was to identify recent international activities in the Unmanned Airborne Systems (UAS) airspace integration problem. The workshop attracted a broad cross-section of the UAS community, including: airspace and safety regulators, developers, operators and researchers. The three themes of discussion were: progress in the development of standards and regulations, lessons learnt from recent operations, and advances in new technologies. This paper summarises the activities of the workshop and explores the important outcomes and trends as perceived by the authors
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