1,439 research outputs found
Is economic planning hypercomputational? The argument from Cantor diagonalisation
Murphy [26] argues that the diagonal argument of the number theorist Cantor can be used to elucidate issues that arose in the socialist calculation debate of the 1930s. In particular he contends that the diagonal argument buttresses the claims of the Austrian economists regarding the impossibility of rational planning.We challenge Murphyâs argument, both at the number theoretic level and from the standpoint of economic realism
Non-classical computing: feasible versus infeasible
Physics sets certain limits on what is and is not computable. These limits are very far from having been reached by current technologies. Whilst proposals for hypercomputation are almost certainly infeasible, there are a number of non classical approaches that do hold considerable promise. There are a range of possible architectures that could be implemented on silicon that are distinctly different from the von Neumann model. Beyond this, quantum simulators, which are the quantum equivalent of analogue computers, may be constructable in the near future
Personnel techniques necessary to maximize bio-barrier integrity at a Martian receiving laboratory
The planning of biological isolation measures for the Mars Surface Sample Return Mission is discussed in terms of personnel and organizational management. Deficiencies in past operation of the Lunar Receiving Laborator are analyzed. It was found that the failure to clearly define relationship among the government agencies involved and to effectively integrate their objectives and responsibilities was a major cause of Laboratory deficiencies. Possible solutions to these problems are presented for application to future missions
Advanced composites wing study program. Volume 1: Executive summary
The effort necessary to achieve a state of production readiness for the design and manufacturing of advanced composite wing structure is outlined. Technical assessment and program options are also reviewed for the wing study results
Predictive Energy Management of Islanded Microgrids with Photovoltaics and Energy Storage
Islanded microgrids powered primarily by photovoltaic (PV) arrays present a challenging control problem due to the intermittent production and the relatively close scale between the sources and the loads. Energy storage in such microgrids plays an important role in balancing supply with demand, and in extending operation during periods when the PV supply is not available or insufficient. The efficient operation of such microgrids requires effective management of all resources. A predictive energy management strategy can potentially avoid or effectively mitigate upcoming outages. This thesis presents an energy management system (EMS) for such microgrids. The EMS uses a predictive approach to set operational schedules in order to (a) prolong the supply to critical system loads and (2) minimize the chances and duration of system-wide outages, specifically through pre-emptive load shedding. Online weather forecast data has been combined with the PV system model to assess potential energy production over a 48 hour period. These predictions, along with load forecasts and a model of the energy storage system, are used to predict the state-of-charge of the storage devices and characterize potential power shortages. Pre-emptive load shedding is subsequently planned and executed to avert outages or minimize the duration of unavoidable outages. A bounding technique has also been proposed to account for uncertainties in estimates of the stored energy. The EMS has been implemented using an event-driven framework with network communication. The approach has been validated through simulations and experiments using recorded real-world solar irradiance data. The results show that the outage durations have been reduced by a factor of 87% to 100% for an example operating scenario, selected to demonstrate the features of the scheme. The impact of uncertainties in the prediction models has also been investigated, specifically for the PV system rating and the battery capacity. A technique has been developed to compensate for such uncertainties by analyzing the data streams from the source and storage units. The technique is applied to the developed EMS strategy, where it is able to shorten the total outage duration by a factor of 12% over a 42-day scenario exhibiting a variety of irradiance conditions
Physical constraints on hypercomputation
Many attempts to transcend the fundamental limitations to computability implied by the Halting Problem for Turing Machines depend on the use of forms of hypercomputation that draw on notions of infinite or continuous, as opposed to bounded or discrete, computation. Thus, such schemes may include the deployment of actualised rather than potential infinities of physical resources, or of physical representations of real numbers to arbitrary precision. Here, we argue that such bases for hypercomputation are not materially realisable and so cannot constitute new forms of effective calculability. A slightly amended version of this has now appeared in the journal Theoretical Computer Science A
Mitigating sampling error when measuring internet client IPv6 capabilities
Despite the predicted exhaustion of unallocated IPv4 addresses be- tween 2012 and 2014, it remains unclear how many current clients can use its successor, IPv6, to access the Internet. We propose a refinement of previous measurement studies that mitigates intrin- sic measurement biases, and demonstrate a novel web-based tech- nique using Google ads to perform IPv6 capability testing on a wider range of clients. After applying our sampling error reduction, we find that 6% of world-wide connections are from IPv6-capable clients, but only 1â2% of connections preferred IPv6 in dual-stack (dual-stack failure rates less than 1%). Except for an uptick around IPv6-day 2011 these proportions were relatively constant, while the percentage of connections with IPv6-capable DNS resolvers has in- creased to nearly 60%. The percentage of connections from clients with native IPv6 using happy eyeballs has risen to over 20
Initial learning scenarios based on the computational thinking evaluation for the course Programming fundamentals at INACAP
The paperâs objective is present the design and the planning of
initial learning scenarios for the course Programming
Fundamentals, from the evaluation of computational thinking to
new students of the careers Computer engineering and
Programmer analyst of the Technological University of Chile and
Training Center Technical respectively at INACAP, to favor the
motivation and autonomy of study through the recognition of
skills and the use of the instructional design of the face-to-face
course. The proposal is based on correspondence with three of five
change trends that integrated the educational model. Regarding
the Knowledge society, promote recognition of the individuality
of the student as a person who will do university studies, that is,
the scenarios respond to the fact that each person learns
differently. In the Training of competences, contribute with
preventive actions that the teacher communicates when there is a
lack of specific skills. Finally, in the Flexibility and articulation,
provide a diagnostic tool that favors the recognition of previous
competences to have an articulated beginning of studies based on
the needs of the student. Consequently, contribute to the
INACAPÂŽs educational model
Forage Quality of White Clover (\u3cem\u3eTrifolium Repens\u3c/em\u3e L.) X Caucasian Clover (\u3cem\u3eT.ambiguum\u3c/em\u3e Bieb.) Hybrids Over Three Harvest Years
Interspecific hybrids have been produced from crosses of white clover, a stoloniferous species with Caucasian clover, a rhizomatous species. Using white clover as the recurrent parent first and second generation backcross (BC1 and BC2) plants have been produced that have both rhizomes and stolons and are more drought tolerant than white clover (Marshall et al., 2001). Forage quality of these interspecific hybrids was investigated to determine whether introgression of the rhizomatous trait has any impact on forage quality
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