Search

Recently, content dissemination has become more and more important for opportunistic social networks. The challenges of opportunistic content dissemination result from random movement of nodes and uncertain positions of a destination, which seriously affect the efficiency of content dissemination. In this paper, we firstly construct time-varying interest communities based on the temporal and spatial regularities of users. Next, we design a content dissemination algorithm on the basis of time-varying interest communities. Our proposed content dissemination algorithm can run in O(nlog⁡n) time. Finally, the comparisons between the proposed content dissemination algorithm and state-of-the-art content dissemination algorithms show that our proposed content dissemination algorithm can (a) keep high query success rate, (b) reduce the average query latency, (c) reduce the hop count of a query, and (d) maintain low system overhead.

Assistive technologies can significantly increase older adults' independent living if these technologies are designed to meet their needs and abilities. This study investigates conditions and present possibilities for assistive technology to provide physical and cognitive support to older adults in a specific domestic task, which is cooking a meal at home. The empirical material consists of six video recordings of adults aged 65 and over preparing a meal in their kitchen. The study unpacks the complexity of kitchen tasks, from the physical interactions involved to the temporal and spatial alignment of objects and goals in the kitchen. We focus on a) Physical manipulation, such as chopping, opening packages, and moving objects around the kitchen, b) Organisation and coordination, including switching, synchronising and monitoring cooking tasks, and c) Reorchestration and reorganisation in the form of inserting additional tasks, and rearranging tools and ingredients when adjustments need to be made in the cooking process. The study outlines design principles for operational and organisational interventions to support cooking a meal for independent living. The study concludes with discussing design implications for conversational user interfaces in the kitchen, and the significance of assistive kitchen technologies for ageing in place.

Calcite veins precipitated in the Estamariu thrust during two tectonic events are studied in order to (i) decipher the temporal and spatial relationships between deformation and fluid migration in a long-lived thrust and (ii) determine the influence of basement rocks on the fluid chemistry during deformation. Structural and petrological observations constrain the relative timing of fluid migration and vein formation, whilst geochemical analyses (13C, 18O, 87Sr=86Sr, clumped isotope thermometry, and elemental composition) applied to the related calcite cements and host rocks indicate the fluid origin, pathways, and extent of fluid rock interaction. The first tectonic event, recorded by calcite cements Cc1a and Cc2, is attributed to the Alpine reactivation of the Estamariu thrust. Analytical data indicate that these cements precipitated from heated meteoric fluids (temperatures in the range of 50 to 100 C) that had interacted with basement rocks (87Sr=86Sr 0.71) before upflowing through the thrust zone. The second tectonic event, attributed to the Neogene extension, is characterized by the reactivation of the Estamariu thrust and the formation of normal faults and shear fractures sealed by calcite cements Cc3, Cc4, and Cc5. Analytical data indicate that cements Cc3 and Cc4 precipitated from hydrothermal fluids (temperatures between 130 and 210 C and between 100 and 170 C, respectively) that had interacted with basement rocks (87Sr=86Sr 0.71) and been expelled through fault zones during deformation. In contrast, cement Cc5 probably precipitated from meteoric waters that likely percolated from the surface through small shear fractures. The comparison between our results and already published data in other structures from the southern Pyrenees suggests that regardless of the origin of the fluids and the tectonic context, basement rocks have a significant influence on the fluid chemistry, particularly on the 87Sr=86Sr ratio. Accordingly, the cements precipitated from fluids that have interacted with basement rocks have significantly higher 87Sr=86Sr ratios (0.710) with respect to those precipitated from fluids that have interacted with the sedimentary cover (0.710), which involves younger and less radiogenic rocks. © 2020 Copernicus GmbH. All rights reserved., This research was carried out within the framework of the DGICYT Spanish project PGC2018-093903-B-C22 (Ministerio de Ciencia, Innovación y Universidades/Agencia Estatal de Investigación/Fondo Europeo de Desarrollo Regional, Unión Europea) and the Grup Consolidat de Recerca “Geologia Sedimentària” (2017-SGR-824). The PhD research of DML is supported by the FPI2016 (BES-2016-077214) Spanish program from MINECO.

Free-electron lasers provide a source of x-ray pulses short enough and intense enough to drive nonlinearities in molecular systems. Impulsive interactions driven by these x-ray pulses provide a way to create and probe valence electron motions with high temporal and spatial resolution. Observing these electronic motions is crucial to understand the role of electronic coherence in chemical processes. A simple nonlinear technique for probing electronic motion, impulsive stimulated x-ray Raman scattering (ISXRS), involves a single impulsive interaction to produce a coherent superposition of electronic states. We demonstrate electronic population transfer via ISXRS using broad bandwidth (5.5eV full width at half maximum) attosecond x-ray pulses produced by the Linac Coherent Light Source. The impulsive excitation is resonantly enhanced by the oxygen 1s→2π^{*} resonance of nitric oxide (NO), and excited state neutral molecules are probed with a time-delayed UV laser pulse.

The widespread use of nanostructures and nanomaterials has opened up a whole new realm of challenges in thermal management, but also leads to possibilities for energy conversion, storage, and generation, in addition to numerous other technological applications. At the microscale and below, standard thermal measurement techniques reach their limits, and several novel methods have been developed to overcome these limitations. Among the most recent, contactless photothermal methods have been widely used and have proved their advantages in terms of versatility, temporal and spatial resolution, and even sensitivity in some situations. Among them, thermoreflectance and Raman thermometry have been used to measure the thermal properties from bulk materials to thin films, multilayers, suspended structures, and nanomaterials. This Tutorial presents the principles of these two techniques and some of their most common implementations. It expands to more advanced systems for spatial mapping and for probing of non-Fourier thermal transport. Finally, this paper concludes with discussing the limitations and perspectives of these techniques and future directions in nanoscale thermometry. I. INTRODUCTION, ICN2 is supported by the Severo Ochoa program from the Spanish Research Agency (AEI, Grant No. SEV-2017-0706) and by the CERCA Programme/Generalitat de Catalunya. ICN2 authors acknowledge support from the Spanish MICINN Project SIP (No. PGC2018-101743-B-I00) and the H2020 European FET Open project PHENOMEN (No. GA 713450). E.C.-A. acknowledges financial support from EU Project NANOPOLY (No. GA 289061). The NTNU authors are supported by the Research Council of Norway through the FRINATEK Project No. 251068 with the title: “Engineering Metal-Polymer Interface for Enhanced Heat Transfer.”

The Peruvian anchovy (Engraulis ringens) is the most important small pelagic of the Humboldt Current System (HCS), supporting the largest mono-specific fishery in the world. The spatial behavior of this species tends to be very dynamic at different spatial scales, influenced mostly by its biomass level and environmental factors. The aim of this study was to analyze temporal and spatial fluctuations in anchovy spatial distribution off Peru, based and modeled on acoustic data, focusing on large- and meso-scale spatial structures. We employed data from 41 scientific surveys (1994–2016) and Bayesian hierarchical spatial models to obtain the anchovy's spatial distribution, allowing us to identify spatial structures at specific scales. Our results showed similar temporal trends in the number of mesoscale structures, their areas and anchovy density, exhibiting altogether two breakpoints in the time series: ~1999 and ~2013. The last period (2013–2016) was similar to the earlier one (1994–1999), in terms of low values of mesoscale structure indicators. On the other hand, we identified four spatial scenarios differentiated by the aggregative behavior, which were highly influenced by seasons and El Nino events. Each scenario had recurrent, or fidelity, areas placed in different locations. For instance, for the ‘El Nino scenario’ a particularly coastal recurrent area was identified, which might be a refuge zone for this species during these unfavorable events. Finally, we assessed differences in biomass estimates of each scenario. The highest biomass values were estimated for the ‘Summer favorable scenario’ and the lowest ones for the ‘El Nino scenario’, which supports the MacCall's basin hypothesis for this species. This study expands the current knowledge of the Peruvian anchovy and it is a first step to understand the effects on this species of the last El Nino events (2014–2016) that occurred in the northern Humboldt Current System.

Straipsnyje svarstoma, kas įvyksta, kai geomokslo terminas antropocenas įsiterpia į etinį diskursą. Teigiama, kad geologinio laiko skalės ir globalios erdvės pasirodymas etinėje savivokoje liudija išsiplėtusį mūsų atsakomybės lauką, tačiau sykiu ši atsakomybė tampa tokia pat efemeriška, kaip ir žmogaus pastanga įsivaizduoti daugiamilijoninę laiko atkarpą. Aptariant keletą išsikristalizavusių strategijų – technologinį-vadybinį ekologinių problemų sprendimą kuriant įvairius geoinžinerijos projektus ir jiems priešingas aplinkosaugines iniciatyvas, akcentuojančias bioįvairovės svarbą, – siekiama išsiaiškinti, ar jos sudaro sąlygas steigtis etiniam subjektui ir etiniam veiksmui. Gretinant Timothy Clarko ir Jacques’o Derrida pozicijas svarstoma, ar žmogiško „lokalaus“, „betarpiško“ veiksmo krizė, atsiradusi dėl įtampos tarp lokalios ir globalios perspektyvų ir neleidžianti aiškiai nuspręsti, koks veiksmas būtų tinkamesnis ekologinės katastrofos akivaizdoje, yra antropoceno etikos negalimybės, ar, priešingai, jos galimybės sąlyga. This article deals with the question what happens when the term “Anthropocene”, originating from geoscience, is incorporated into ethical discourse. The author argues that the appearance of geological time scales and global space in ethical self-perception testifies the extension of the field of our responsibility, but at the same time this responsibility becomes as ephemeral as the human effort to imagine a multimillion-time span. By discussing two strategies that have been crystallized – technological-managerial solutions to ecological problems implemented through the development of various geoengineering projects and environmental initiatives that emphasize the importance of biodiversity – the author seeks to determine whether they allow for the establishment of an ethical subject and ethical action. Comparing Timothy Clark’s and Jacques Derrida’s positions, the author discusses whether the crisis of human “local”, “immediate” action, resulting from the tension between local and global perspectives and precluding a clear decision on what would be more appropriate in the face of the ecological catastrophe, is a condition of impossibility of ethics in the Anthropocene or, quite the reverse, its possibility.

In recent years Mobile Network Operators (MNOs) worldwide are extensively deploying LTE networks in different spectrum bands and utilising different bandwidth configurations. Initially, the deployment is coverage oriented with macro cells using the lower LTE spectrum bands. As the offered traffic (i.e. the requested traffic from the users) increases the LTE deployment evolves with macro cells expanded with additional capacity boosting LTE carriers in higher frequency bands complemented with micro or small cells in traffic hotspot areas. For MNOs it is crucial to use the LTE spectrum assets, as well as the installed network infrastructure, in the most cost efficient way. The dynamic spectrum allocation (DSA) aims at (de)activating the available LTE frequency carriers according to the temporal and spatial traffic variations in order to increase the overall LTE system performance in terms of total network capacity by reducing the interference. This paper evaluates the DSA potential of achieving the envisaged performance improvement and identifying in which system and traffic conditions the DSA should be deployed. A self-optimised network (SON) DSA algorithm is also proposed and evaluated. The evaluations have been carried out in a hexagonal and a realistic site-specific urban macro layout assuming a central traffic hotspot area surrounded with an area of lower traffic with a total size of approximately 8 × 8 km2. The results show that up to 47 % and up to 40 % possible DSA gains are achievable with regards to the carried system load (i.e. used resources) for homogenous traffic distribution with hexagonal layout and for realistic site-specific urban macro layout, respectively. The SON DSA algorithm evaluation in a realistic site-specific urban macro cell deployment scenario including realistic non-uniform spatial traffic distribution shows insignificant cell throughput (i.e. served traffic) performance gains. Nevertheless, in the SON DSA investigations, a gain of up to 25 % has been observed when analysing the resource utilisation in the non-hotspot cells.

Quantum fluids of light are an emerging tool employed in quantum many-body physics. Their amazing properties and versatility allow using them in a wide variety of fields including gravitation, quantum information and simulation. However the implications of the quantum nature of light in the nonlinear optical propagation are still missing many features. We theoretically predict classical spontaneous squeezing of a photon fluid in a nonlocal nonlinear medium. By using the so called Gamow vectors, we show that the quadratures of a coherent state get squeezed and that a maximal squeezing power exists. Our analysis holds true for temporal and spatial optical propagation in highly nonlocal regime. These results open a new scenario in quantum photon fluids and may lead to novel applications in fields like metrology and analogues of quantum gravity., 6 pages, 2 figures

In our increasingly connected and instrumented world, live data recording the interactions between people, systems, and the environment is available in various domains, such as telecommunciations and social media. This data often takes the form of a temporally evolving graph, where entities are the vertices and the interactions between them are the edges. An important feature of this graph is that the number of edges it has grows continuously, as new interactions take place. We call such graphs interaction graphs. In this paper we study the problem of storing interaction graphs such that temporal queries on them can be answered efficiently. Since interaction graphs are append-only and edges are added continuously, traditional graph layout and storage algorithms that are batch based cannot be applied directly. We present the design and implementation of a system that caches recent interactions in memory, while quickly placing the expired interactions to disk blocks such that those edges that are likely to be accessed together are placed together. We develop live block formation algorithms that are fast, yet can take advantage of temporal and spatial locality among the edges to optimize the storage layout with the goal of improving query performance. We evaluate the system on synthetic as well as real-world interaction graphs, and show that our block formation algorithms are effective for answering temporal neighborhood queries on the graph. Such queries form a foundation for building more complex online and offline temporal analytics on interaction graphs. © 1989-2012 IEEE.

In the present study, breakdown characteristics of a glass fiber reinforced plastic (GFRP) with different salt deposit densities (SDD) under standard lightning impulse (LI)/ switching impulse (SI) voltages are studied. Optical emission during discharge process and the discharge current are measured simultaneously. It is observed that flashover voltage (FOV) reduces with increase in salt deposit density on GFRP material under LI/SI (irrespective of the polarity of applied voltage) voltages. It is also observed that irrespective of level of SDD, the FOV is less with SIV compared with LIV. FOV under negative SIV is less compared with positive SIV. Optical emission corresponding to Na I emission at 589 nm in discharge plasma follows the discharge current profile and also the lifetime of Na I emission is high under switching impulse compared with lightning impulse voltages. Na I emission in the discharge plasma sustains for a longer period in case of negative switching impulse voltages. Plasma temperature is estimated using emission lines and it is observed that the local temperature during discharge process is high under negative switching impulse voltage. With increase in salt deposit density, the optical emission spectrum of GFRP material in addition of Na I line at 589 nm is observed. Laser induced breakdown spectroscopy (LIBS) technique is proposed and demonstrated for the detection of a salt deposit on a GFRP material from a standoff distance of 1 m. In addition, temporal and spatial profile of laser induced plasma on the polluted GFRP material is used to quantify the salt deposit. Laser fluence less than 5 J/cm 2 is ideally suited to rank the severity of a salt deposit on GFRP material at an incident laser wavelength of 1064 nm.

Boundary layers are subject to favorable and adverse pressure gradients because of both the temporal and spatial components of the pressure gradient. The adverse pressure gradient may cause the flow to separate. In a closed loop unsteady tunnel we have studied the initiation of separation in unsteady flow past a constriction (bluff body) in a channel. We have proposed two important scalings for the time when boundary layer separates. One is based on the local pressure gradient and the other is a convective time scale based on boundary layer parameters. The flow visualization using a dye injection technique shows the flow structure past the body. Nondimensional shedding frequency (Strouhal number) is calculated based on boundary layer and momentum thicknesses. Strouhal number based on the momentum thickness shows a close agreement with that for flat plate and circular cylinder. � 2013 Elsevier Ltd.

SUMMARYThe incursion of influenza A(H1N1)pdm09 virus was detected by Norway's active serosurveillance of its pig population in 2009. Since then, surveillance data from 2010 to 2014 revealed that 54% of 5643 herd tests involving 1567 pig herds and 28% of 23 036 blood samples screened positive for antibodies against influenza A virus. Positive herds were confirmed to have influenza A(H1N1)pdm09 virus infection by haemagglutination inhibition test. In 50% of positive herd tests, ⩾60% of the sampled pigs in each herd had antibodies against influenza A(H1N1)pdm09 virus. This within-herd animal seroprevalence did not vary for type of production, herd size or year of test. The overall running mean of national herd seroprevalence, and annual herd incidence risks fluctuated narrowly around the means of 45% and 32%, respectively, with the highest levels recorded in the three densest pig-producing counties. The probability of a herd being seropositive varied in the five production classes, which were sow pools, multiplier herds, conventional sow herds, nucleus herds, and fattening herds in descending order of likelihood. Large herds were more likely to be seropositive. Seropositive herds were highly likely to be seropositive the following year. The study shows that influenza A(H1N1)pdm09 virus is established in the Norwegian pig population with recurrent and new herd infections every year with the national herd seroprevalence in 2014 hovering at around 43% (95% confidence interval 40–46%).

The urban traffic network has temporal and spatial characteristics whose changing conditions have often unpredictable effects on the flow of loads that include passengers and freight. As a result, the current traffic network is unbalanced, leading to high and low peaks of traffic in both time and space. The freight transportation chain can utilize these high and low peaks in the road and rail network in order to utilize more effectively available capacity. The purpose of this paper is to develop a coordinated multimodal dynamic freight load balancing (MDFLB) system to balance freight loads across the rail and road network. The MDFLB system collects and updates information from all the shipping companies and assigns freight loads to the available carriers using an optimization model while taking into account current and predicted dynamical changes in the associated networks. Since the freight loads can change the assumed states of the network, namely, the link travel times, which could then render the solution of the optimization problem no longer optimum, an iterative approach is considered involving online network simulation models. The simulation models are used to test and modify the optimization-based load balancing solution and estimate the new states of the network used by the optimizer. This feedback iterative approach guarantees that the overall cost function is non-increasing and it stops when it converges to a minimum or when a stopping criterion is satisfied depending on the time horizon of interest. A simulation case study that focuses on distribution of freight in an area that includes the two major sea ports in Southern California is used to demonstrate the effectiveness of the proposed coordinated MDFLB. © 2015 IEEE. 17 2 356 366

In recent years Mobile Network Operators (MNOs) worldwide are extensively deploying LTE networks in different spectrum bands and utilising different bandwidth configurations. Initially, the deployment is coverage oriented with macro cells using the lower LTE spectrum bands. As the offered traffic (i.e. the requested traffic from the users) increases the LTE deployment evolves with macro cells expanded with additional capacity boosting LTE carriers in higher frequency bands complemented with micro or small cells in traffic hotspot areas. For MNOs it is crucial to use the LTE spectrum assets, as well as the installed network infrastructure, in the most cost efficient way. The dynamic spectrum allocation (DSA) aims at (de)activating the available LTE frequency carriers according to the temporal and spatial traffic variations in order to increase the overall LTE system performance in terms of total network capacity by reducing the interference. This paper evaluates the DSA potential of achieving the envisaged performance improvement and identifying in which system and traffic conditions the DSA should be deployed. A self-optimised network (SON) DSA algorithm is also proposed and evaluated. The evaluations have been carried out in a hexagonal and a realistic site-specific urban macro layout assuming a central traffic hotspot area surrounded with an area of lower traffic with a total size of approximately 8 × 8 km2. The results show that up to 47 % and up to 40 % possible DSA gains are achievable with regards to the carried system load (i.e. used resources) for homogenous traffic distribution with hexagonal layout and for realistic site-specific urban macro layout, respectively. The SON DSA algorithm evaluation in a realistic site-specific urban macro cell deployment scenario including realistic non-uniform spatial traffic distribution shows insignificant cell throughput (i.e. served traffic) performance gains. Nevertheless, in the SON DSA investigations, a gain of up to 25 % has been observed when analysing the resource utilisation in the non-hotspot cells. © 2015 Author(s).

As infrastructure networks become more complex and intertwined, the relevance of network interdependency research is increasingly evident. Interconnected networks bring about efficiencies during normal operations but also come with risks of cascading failures with disaster events. An adequate understanding of network interdependencies and realistic multi-system modeling capabilities enable the exploration of practical operation strategies and mitigation efforts applicable to existing or future coupled networked systems. This paper examines recent efforts in quantifying infrastructure network interdependencies through spatial and time-series analyses to reveal the heterogeneity and complexity in their coupling. Furthermore, a combined spatial-temporal methodology is recommended for the future calibration and validation of theoretical and computational models of interdependent networks of networks that support resilience assessment. Example case studies are demonstrated using data derived from the 2010 Chilean Earthquake in the Talcahuano-Concepcion region and the 2010-2011 Canterbury-Christchurch earthquake sequence in New Zealand. The case studies highlight the richness in coupling strengths across infrastructure systems, both as a function of time and geographical extent. Insights for design, control, and resilience enhancement of coupled networks are also derivable from joint spatial-temporal analyses of infrastructure interdependencies and their evolution.

Life Cycle Analysis (LCA) has recently emerged as a powerful tool for assessing the environmental impact of materials, systems and processes used in building construction. With its ability to clarify the ambiguities of the conventional wisdom related to sustainable practices, LCA provides quantifiable results encompassing every environmental effect associated with the "cradle to grave" journey of a product. To make better use of LCA results in decision making, normalization is recommended following the impact assessment step. Normalization is a step carried out in order to compare results of every indicator under the LCA impact categories with some temporal and spatial reference. The objective of this paper is to present a framework for calculating the normalization factors for the State of Qatar with reference to annual total emissions or resource consumption per capita. The data required to perform this task is identified along with its sources and any possible gaps. These gaps are addressed using the appropriate methods in order to develop guidelines for establishing a comprehensive record of emissions and resource consumption for the State of Qatar. As a result, the proposed framework will be used to calculate normalization factors for impact categories chosen by the Qatar Green Building Council (QGBC) as the basis for the Qatari LCA database currently under development. Scopus

[Departement_IRSTEA]Territoires [TR1_IRSTEA]SYNERGIE [Departement_IRSTEA]Territoires [TR1_IRSTEA]SYNERGIEISBN : 978-163266234-7; National audience; Georeferenced databases contain a huge volume of temporal and spatial data. They are notably used in environmental analysis. Several works address the problem of mining those data, but none are able to take into account the richness of the data and especially their spatial and temporal dimensions. In this paper, we focus on the extraction of a new kind of spatiotemporal patterns which consider the relationship between spatial objects and also various geographical scales. We propose an algorithm, STR_PrefixGrowth, which can be applied on a huge amont of data. The proposed method is evaluated on hydrological data collected on the Saône basin during the last 19 years. Our experiments emphasize the contribution of our approach toward the existing methods.; Les bases de données géoréférencées contiennent un important volume de données temporelles et spatiales. Elles sont par exemple particulièrement utilisées dans le cadre d'analyses environnementales. Plusieurs méthodes ont été proposées pour l'exploration de telles bases de données, mais aucune ne permet d'exploiter toute la richesse des données, en particulier leurs dimensions spatiales et temporelles. Dans cet article, nous introduisons un nouveau type de motifs spatio-temporels considérant les relations entre objets spatiaux mais aussi les différentes échelles géographiques. Nous proposons un algorithme d'extraction de motifs STR_PrefixGrowth applicable sur un important volume de données. Nous traitons un exemple de données hydrobiologiques collectées sur le bassin de la Saône durant les 19 dernières années. Les expérimentations menées soulignent l'intérêt de notre méthode par rapport aux méthodes existantes.