199 research outputs found
The use of fusion/real time centers by law enforcement
Discusses the use of fusion centers as a way to effectively gather, analyze and share information among law enforcement agencies
A global-scale screening of non-native aquatic organisms to identify potentially invasive species under current and future climate conditions
The threat posed by invasive non-native species worldwide requires a global approach to identify which introduced species are likely to pose an elevated risk of impact to native species and ecosystems. To inform policy, stakeholders and management decisions on global threats to aquatic ecosystems, 195 assessors representing 120 risk assessment areas across all six inhabited continents screened 819 non-native species from 15 groups of aquatic organisms (freshwater, brackish, marine plants and animals) using the Aquatic Species Invasiveness Screening Kit. This multi-lingual decision-support tool for the risk screening of aquatic organisms provides assessors with risk scores for a species under current and future climate change conditions that, following a statistically based calibration, permits the accurate classification of species into high-, medium- and low-risk categories under current and predicted climate conditions. The 1730 screenings undertaken encompassed wide geographical areas (regions, political entities, parts thereof, water bodies, river basins, lake drainage basins, and marine regions), which permitted thresholds to be identified for almost all aquatic organismal groups screened as well as for tropical, temperate and continental climate classes, and for tropical and temperate marine ecoregions. In total, 33 species were identified as posing a ‘very high risk’ of being or becoming invasive, and the scores of several of these species under current climate increased under future climate conditions, primarily due to their wide thermal tolerances. The risk thresholds determined for taxonomic groups and climate zones provide a basis against which area-specific or climate-based calibrated thresholds may be interpreted. In turn, the risk rankings help decision-makers identify which species require an immediate ‘rapid’ management action (e.g. eradication, control) to avoid or mitigate adverse impacts, which require a full risk assessment, and which are to be restricted or banned with regard to importation and/or sale as ornamental or aquarium/fishery enhancement. © 2021 The Authors. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Lance Lloyd" is provided in this record*
Examples of Gaussian cluster computation
We give simple examples that illustrate the principles of one-way quantum
computation using Gaussian continuous-variable cluster states. In these
examples, we only consider single-mode evolutions, realizable via linear
clusters. In particular, we focus on Gaussian single-mode transformations
performed through the cluster state. Our examples highlight the differences
between cluster-based schemes and protocols in which special quantum states are
prepared off-line and then used as a resource for the on-line computation.Comment: 15 pages, 3 figure
Estuary environmental flows assessment methodology for Victoria
This report sets out a method to determine the environmental water requirements of estuaries in Victoria. The estuary environmental flows assessment method (EEFAM) is a standard methodology which can be applied consistently across Victorian estuaries.The primary objective of EEFAM is to define a flow regime to maintain or enhance the ecological health of an estuary. The method is used to inform Victorian water resource planning processes.The output of EEFAM is a recommended flow regime for estuaries. This recommendation is developed from the known dependence of the estuary’s flora, fauna, biogeochemical and geomorphological features on the flow regime. EEFAM is an evidence-based methodology. This bottom-up or ‘building block’ approach conforms to the asset-based approach of the Victorian River Health Strategy and regional river health strategies.EEFAM is based on and expands on FLOWS, the Victorian method for determining environmental water requirements in rivers. The list of tasks has been modified and re-ordered in EEFAM to reflect environmental and management issues specific to estuaries. EEFAM and FLOWS can be appliedsimultaneously to a river and its estuary as part of a whole-of-system approach to environmental flow requirements. Like the FLOWS method, EEFAM is modular, and additional components can be readily incorporated
Non-Gaussian states for continuous variable quantum computation via Gaussian maps
We investigate non-Gaussian states of light as ancillary inputs for
generating nonlinear transformations required for quantum computing with
continuous variables. We consider a recent proposal for preparing a cubic phase
state, find the exact form of the prepared state and perform a detailed
comparison to the ideal cubic phase state. We thereby identify the main
challenges to preparing an ideal cubic phase state and describe the gates
implemented with the non-ideal prepared state. We also find the general form of
operations that can be implemented with ancilla Fock states, together with
Gaussian input states, linear optics and squeezing transformations, and
homodyne detection with feed forward, and discuss the feasibility of continuous
variable quantum computing using ancilla Fock states.Comment: 8 pages, 6 figure
A Comparative Study of Efficient Initialization Methods for the K-Means Clustering Algorithm
K-means is undoubtedly the most widely used partitional clustering algorithm.
Unfortunately, due to its gradient descent nature, this algorithm is highly
sensitive to the initial placement of the cluster centers. Numerous
initialization methods have been proposed to address this problem. In this
paper, we first present an overview of these methods with an emphasis on their
computational efficiency. We then compare eight commonly used linear time
complexity initialization methods on a large and diverse collection of data
sets using various performance criteria. Finally, we analyze the experimental
results using non-parametric statistical tests and provide recommendations for
practitioners. We demonstrate that popular initialization methods often perform
poorly and that there are in fact strong alternatives to these methods.Comment: 17 pages, 1 figure, 7 table
Quantum optical coherence can survive photon losses: a continuous-variable quantum erasure correcting code
A fundamental requirement for enabling fault-tolerant quantum information
processing is an efficient quantum error-correcting code (QECC) that robustly
protects the involved fragile quantum states from their environment. Just as
classical error-correcting codes are indispensible in today's information
technologies, it is believed that QECC will play a similarly crucial role in
tomorrow's quantum information systems. Here, we report on the first
experimental demonstration of a quantum erasure-correcting code that overcomes
the devastating effect of photon losses. Whereas {\it errors} translate, in an
information theoretic language, the noise affecting a transmission line, {\it
erasures} correspond to the in-line probabilistic loss of photons. Our quantum
code protects a four-mode entangled mesoscopic state of light against erasures,
and its associated encoding and decoding operations only require linear optics
and Gaussian resources. Since in-line attenuation is generally the strongest
limitation to quantum communication, much more than noise, such an
erasure-correcting code provides a new tool for establishing quantum optical
coherence over longer distances. We investigate two approaches for
circumventing in-line losses using this code, and demonstrate that both
approaches exhibit transmission fidelities beyond what is possible by classical
means.Comment: 5 pages, 4 figure
Continuous Variable Quantum Cryptography using Two-Way Quantum Communication
Quantum cryptography has been recently extended to continuous variable
systems, e.g., the bosonic modes of the electromagnetic field. In particular,
several cryptographic protocols have been proposed and experimentally
implemented using bosonic modes with Gaussian statistics. Such protocols have
shown the possibility of reaching very high secret-key rates, even in the
presence of strong losses in the quantum communication channel. Despite this
robustness to loss, their security can be affected by more general attacks
where extra Gaussian noise is introduced by the eavesdropper. In this general
scenario we show a "hardware solution" for enhancing the security thresholds of
these protocols. This is possible by extending them to a two-way quantum
communication where subsequent uses of the quantum channel are suitably
combined. In the resulting two-way schemes, one of the honest parties assists
the secret encoding of the other with the chance of a non-trivial superadditive
enhancement of the security thresholds. Such results enable the extension of
quantum cryptography to more complex quantum communications.Comment: 12 pages, 7 figures, REVTe
Disease-driven Reduction in Human Mobility Influences Human-Mosquito Contacts and Dengue Transmission Dynamics
Heterogeneous exposure to mosquitoes determines an individual’s contribution to vector-borne pathogen transmission. Particularly for dengue virus (DENV), there is a major difficulty in quantifying human-vector contacts due to the unknown coupled effect of key heterogeneities. To test the hypothesis that the reduction of human out-of-home mobility due to dengue illness will significantly influence population-level dynamics and the structure of DENV transmission chains, we extended an existing modeling framework to include social structure, disease-driven mobility reductions, and heterogeneous transmissibility from different infectious groups. Compared to a baseline model, naïve to human pre-symptomatic infectiousness and disease-driven mobility changes, a model including both parameters predicted an increase of 37% in the probability of a DENV outbreak occurring; a model including mobility change alone predicted a 15.5% increase compared to the baseline model. At the individual level, models including mobility change led to a reduction of the importance of out-of-home onward transmission (R, the fraction of secondary cases predicted to be generated by an individual) by symptomatic individuals (up to -62%) at the expense of an increase in the relevance of their home (up to +40%). An individual’s positive contribution to R could be predicted by a GAM including a non-linear interaction between an individual’s biting suitability and the number of mosquitoes in their home (\u3e10 mosquitoes and 0.6 individual attractiveness significantly increased R). We conclude that the complex fabric of social relationships and differential behavioral response to dengue illness cause the fraction of symptomatic DENV infections to concentrate transmission in specific locations, whereas asymptomatic carriers (including individuals in their pre-symptomatic period) move the virus throughout the landscape. Our findings point to the difficulty of focusing vector control interventions reactively on the home of symptomatic individuals, as this approach will fail to contain virus propagation by visitors to their house and asymptomatic carriers
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