720 research outputs found

    An Interactive Tool to Explore and Improve the Ply Number of Drawings

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    Given a straight-line drawing Γ\Gamma of a graph G=(V,E)G=(V,E), for every vertex vv the ply disk DvD_v is defined as a disk centered at vv where the radius of the disk is half the length of the longest edge incident to vv. The ply number of a given drawing is defined as the maximum number of overlapping disks at some point in R2\mathbb{R}^2. Here we present a tool to explore and evaluate the ply number for graphs with instant visual feedback for the user. We evaluate our methods in comparison to an existing ply computation by De Luca et al. [WALCOM'17]. We are able to reduce the computation time from seconds to milliseconds for given drawings and thereby contribute to further research on the ply topic by providing an efficient tool to examine graphs extensively by user interaction as well as some automatic features to reduce the ply number.Comment: Appears in the Proceedings of the 25th International Symposium on Graph Drawing and Network Visualization (GD 2017

    Maximum flow-based formulation for the optimal location of electric vehicle charging stations

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    With the increasing effects of climate change, the urgency to step away from fossil fuels is greater than ever before. Electric vehicles (EVs) are one way to diminish these effects, but their widespread adoption is often limited by the insufficient availability of charging stations. In this work, our goal is to expand the infrastructure of EV charging stations, in order to provide a better quality of service in terms of user satisfaction (and availability of charging stations). Specifically, our focus is directed towards urban areas. We first propose a model for the assignment of EV charging demand to stations, framing it as a maximum flow problem. This model is the basis for the evaluation of user satisfaction with a given charging infrastructure. Secondly, we incorporate the maximum flow model into a mixed-integer linear program, where decisions on the opening of new stations and on the expansion of their capacity through additional outlets is accounted for. We showcase our methodology for the city of Montreal, demonstrating the scalability of our approach to handle real-world scenarios. We conclude that considering both spacial and temporal variations in charging demand is meaningful when solving realistic instances

    A Diagnostic Examination of the Eastern Ontario and Western Quebec Wintertime Convection Event of 28 January 2010

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    The priority of an operational forecast center is to issue watches, warnings, and advisories to notify the public about the inherent risks and dangers of a particular event. Occasionally, events occur that do not meet advisory or warning criteria, but still have a substantial impact on human life and property. Short-lived snow bursts are a prime example of such a phenomenon. While these events are typically characterized by small snow accumulations, they often cause very low visibilities and rapidly deteriorating road conditions, both of which are a major hazard to motorists. On the afternoon of 28 January 2010, two such snow bursts moved through the Ottawa River valley and lower St. Lawrence River valley, and created havoc on area roads, resulting in collisions and injuries. Using the National Centers for Environmental Prediction (NCEP) North American Regional Reanalysis (NARR), these snow bursts were found to be associated with an approaching strong upper-tropospheric trough and the passage of an arctic front. While convection or squall lines are not common in January in Canada, snow bursts are shown to be associated with strong quasigeostrophic forcing for ascent and low-level frontogenesis, in the presence of both convective and conditional symmetric instability. Finally, this paper highlights the need for the development of a standard subadvisory criterion warning of short-lived but high-impact winter weather events, which operational forecasters can issue and quickly disseminate to the general public

    Prenatal Diagnosis of Gómez-López-Hernández Syndrome.

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    Gómez-López-Hernández syndrome (GLHS), also known as cerebello-trigeminal-dermal dysplasia, is an extremely rare neurocutaneous disease, classically described by the triad of rhombencephalosynapsis (RES), bilateral focal alopecia, and trigeminal anesthesia. The clinical and radiographic spectrum of GLHS is now known to be broader, including craniofacial and supratentorial anomalies, as well as neurodevelopmental issues. Here, we present a case of antenatally diagnosed GLHS with RES, hydrocephaly, and craniofacial anomalies identified on ultrasound (low-set ears with posterior rotation, hypertelorism, midface hypoplasia, micrognathia, and anteverted nares) which were confirmed by autopsy after termination of pregnancy at 23 weeks of gestation. As no known genetic causes have been identified and the classical triad is not applicable to prenatal imaging, prenatal diagnosis of GLHS is based on neuroimaging and the identification of supporting features. In presence of an RES associated with craniofacial abnormalities in prenatal (brachycephaly, turricephaly, low-set ears, midface retrusion, micrognathia), GLHS should be considered as "possible" according to postnatal criteria

    Natural Language Watermarking and Tamperproofing

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    Two main results in the area of information hiding in natural language text are presented. A semantically-based scheme dramatically improves the information-hiding capacity of any text through two techniques: (i) modifying the granularity of meaning of individual sentences, whereas our own previous scheme kept the granularity fixed, and (ii) halving the number of sentences affected by the watermark. No longer a "long text, short watermark" approach, it now makes it possible to watermark short texts like wire agency reports. Using both the above-mentioned semantic marking scheme and our previous syntactically-based method hides information in a way that reveals any non-trivial tampering with the text (while re-formatting is not considered to be tampering---the problem would be solved trivially otherwise by hiding a hash of the text) with a probability 1--2 , n being its number of sentences and a small positive integer based on the extent of co-referencing

    Interventions for improving recovery from work

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    ObjectivesThis is a protocol for a Cochrane Review (intervention). The objectives are as follows:To compare the effectiveness of different individual interventions in recovery from work.info:eu-repo/semantics/publishedVersio

    Iraqi refugees in Egypt: an exploration of their mental health and psychosocial status

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    Thousands of Iraqis have settled in Egypt since 2003, escaping death threats, torture, kidnappings and military attacks to face uncertainty in their lives and increasing strain on the psychosocial challenges in their new lives. This explorative study describes the psychosocial stress faced by these Iraqi refugees in Egypt. Two hundred and four Iraqis in Egypt ¢lled in a checklist focussing on four groups of stress factors.The data provided by this study demonstrate the contribution of violence to Iraqi refugees'life from a number of sources. More than 56% have experienced multiple traumatic situations before immigration and the refugees themselves report major impacts on their health, mental health and socioeconomic demands. A motivated desire to return home was preferred by only one third of respondents

    Grid’BnB: A Parallel Branch and Bound Framework for Grids

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    The Wintertime Southern Hemisphere Split Jet: Structure, Variability, and Evolution

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    A persistent feature of the Southern Hemisphere upper-level time-mean flow is the presence of a split jet across the South Pacific east of Australia during the austral winter. The split jet is composed of the subtropical jet (STJ) on its equatorward branch and the polar front jet (PFJ) on its poleward branch. The NCEP-NCAR reanalysis is used to investigate the structure and evolution of the split jet. Results show that the presence/absence of the PFJ determines the degree of split flow, given that the STJ is a quasi-steady feature. A split-flow index (SFI) is developed to quantify the variability of the split jet, in which negative values represent strong split flow and positive values nonsplit flow. Correlations with teleconnection indices are investigated, with the SFI positively correlated to the Southern Oscillation index and negatively correlated to the Antarctic oscillation. The SFI is used to construct composites of heights, temperature, and wind for split-flow and non-split-flow days. The composites reveal that relatively cold conditions occur in the South Pacific in association with non-split-flow regimes, and split-flow regimes occur when relatively warm conditions prevail. In the latter situation cold air bottled up over Antarctica helps to augment the background tropospheric thickness gradient between Antarctica and the lower latitudes with a resulting increase in the thermal wind and the PFJ. It is surmised that frequent cold surges out of Antarctica moving into the South Pacific are associated with non-split-flow regimes. In this context, the variability of the split jet responds to large-scale baroclinic processes and is further modulated by synoptic-scale disturbances
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