A data-synthesis-driven method for detecting and extracting vague cognitive regions     

Song Gao  Krzysztof Janowicz  Daniel R. Montello  Yingjie Hu  Jiue-An Yang  Grant McKenzie 《International journal of geographical information science》2017,31(6):1245-1271

Cognitive regions and places are notoriously difficult to represent in geographic information science and systems. The exact delineation of cognitive regions is challenging insofar as borders are vague, membership within the regions varies non-monotonically, and raters cannot be assumed to assess membership consistently and homogeneously. In a study published in this journal in 2014, researchers devised a novel grid-based task in which participants rated the membership of individual cells in a given region and contrasted this approach to a standard boundary-drawing task. Specifically, the authors assessed the vague cognitive regions of Northern California and Southern California. The boundary between these cognitive regions was found to have variable width, and region membership peaked not at the most northern or southern cells but at substantially less extreme latitudes. The authors thus concluded that region membership is about attitude, not just latitude. In the present work, we reproduce this study by approaching it from a computational fourth-paradigm perspective, i.e., by the synthesis of high volumes of heterogeneous data from various sources. We compare the regions which we identify to those from the human-participants study of 2014, identifying differences and commonalities. Our results show a significant positive correlation to those in the original study. Beyond the extracted regions themselves, we compare and contrast the empirical and analytical approaches of these two methods, one a conventional human-participants study and the other an application of increasingly popular data-synthesis-driven research methods in GIScience.  相似文献   

A Global Approach to the Spatial Diversity and Dynamics of Internet Domains   总被引：1，自引：0，他引：1       下载免费PDF全文

Krzysztof Janc 《Geographical review》2016,106(4):567-587

The objective of this paper is to describe the place of individual countries in digital space through the lens of Internet domains and specific websites. We will discuss the global geography of domains in reference to states and other entities of spatial organization, and changes in the positions of individual websites. These issues will be approached with an awareness of the significant changes taking place in the functioning of the Web, particularly cyberbalkanization. This study mainly used data from Alexa rankings, the best free source of information available on the behavior of Internet users. One conclusion is the clear U.S. dominance over other countries in relation to number of most popular domains. Despite the clear U.S. dominance, the BRIC countries—Brazil, Russia, India, and China—play an increasingly significant role in the geography of domains. The trends discussed in this article are related to the so‐called balkanization of the Internet. Regulations of its functioning and the growing importance of national websites and search engines have contributed to deepening the differences between Internet users in different countries.  相似文献   

Crowdsensing smart ambient environments and services   总被引：3，自引：1，他引：2       下载免费PDF全文

Blake Regalia  Grant McKenzie  Song Gao  Krzysztof Janowicz 《Transactions in GIS》2016,20(3):382-398

Whether it be Smart Cities, Ambient Intelligence, or the Internet of Things, current visions for future urban spaces share a common core, namely the increasing role of distributed sensor networks and the on‐demand integration of their data to power real‐time services and analytics. Some of the greatest hurdles to implementing these visions include security risks, user privacy, scalability, the integration of heterogeneous data, and financial cost. In this work, we propose a crowdsensing mobile‐device platform that empowers citizens to collect and share information about their surrounding environment via embedded sensor technologies. This approach allows a variety of urban areas (e.g., university campuses, shopping malls, city centers, suburbs) to become equipped with a free ad‐hoc sensor network without depending on proprietary instrumentation. We present a framework, namely the GeoTracer application, as a proof‐of‐concept to conduct multiple experiments simulating use‐case scenarios on a university campus. First, we demonstrate that ambient sensors (e.g. temperature, pressure, humidity, magnetism, illuminance, and audio) can help determine a change in environment (e.g. moving from indoors to outdoors, or floor changes inside buildings) more accurately than typical positioning technologies (e.g. global navigation satellite system, Wi‐Fi, etc.). Furthermore, each of these sensors contributes a different amount of data to detecting events. for example, illuminance has the highest information gain when trying to detect changes between indoors and outdoors. Second, we show that through this platform it is possible to detect and differentiate place types on a university campus based on inferences made through ambient sensors. Lastly, we train classifiers to determine the activities that a place can afford at different times (e.g. good for studying or not, basketball courts in use or empty) based on sensor‐driven semantic signatures.  相似文献   

Polymetallic sulfide ores hosted in Late Permian carbonate at the Alanish locality,northern Iraq: petrography and mineral chemistry     

Salih M. Awadh  Krzysztof Nejbert 《Arabian Journal of Geosciences》2016,9(9):540

Polymetallic sulfide ores (Zn, Pb, Fe, Cu, Ag, and Cd) found in the Alanish locality of northern Iraq are hosted by dolostone in the Late Permian Chia Zairi Formation. The Alanish locality is one of several Zn–Pb deposits that are widespread in northern Iraq, situated along the northern passive margin of the Arabian plate. This paper describes the ore deposit classification, mineral chemistry, and paragenetic sequence of the area and proposes an ore formation model. We report the presence of acanthite and greenockite for the first time in Iraq. A brine solution derived from the sedimentary basin formed the primary sulfide ore minerals (sphalerite, galena, acanthite, pyrite, chalcopyrite, greenockite, and marcasite). The pre-tectonic mineralization is characterized by replacement textures including (1) high-Fe, low-Zn, dark-colored, coarse-grained sphalerite; (2) deformed anisotropic coarse-grained galena; and, (3) idiomorphic cubes of crushed pyrite. Conversely, the post-tectonic mineralization is characterized by open-space filling textures, including (1) low-Fe, high-Zn, light-colored, fine aggregated sphalerite; (2) fine-grained galena; and, (3) the existence of acanthite and marcasite. Although galena is an Ag carrier, both mineralization phases contained non-argentiferous galena. Non-sulfides (smithsonite, cerussite, and goethite) have replaced older sulfides in many areas due to supergene process. Gangue minerals present are dolomite, calcite, barite, and siderite. Open spaces and cavity filling of small paleo-karsts, replacement, veins, and veinlets are common features of the ore body. Metals were sourced from brines generated in the sedimentary basin, whereas sulfur was derived from nearby evaporates. Sediment compaction and tectonic activity, probably during Late Cretaceous, were the driving forces that squeezed and moved ore-bearing fluids derived from the sedimentary basin. Multiple stages of ore-bearing fluids were epigenetically intruded into the Late Paleozoic dolostone, forming an epigenetic strata-bound Mississippi Valley-type deposit precipitated under a temperature of 120 °C, as indicated by the cadmium fractionation in sphalerite and galena. Dolomitization and tectonic activity provided the necessary permeability for accumulating ores. The main ore body is directly connected to a fault plane and to adjacent dolostone that is frequently fractured and brecciated.  相似文献   

Graupel growth and trajectories in a shallow cb cloud determined by a forced 1‐D model     

Mladjen Ćurić  Dejan Janc 《大气与海洋》2013,51(3):462-478

Abstract

A kinematic model is applied to graupel growth. The vertical velocity and ther‐modynamic field data are taken from the forced 1‐D time‐dependent model of Cb cloud developed by Curie and Jane (1988). The graupel embryo pocket was released at the height of the — 10°C isotherm. The influence of the forced lifting on further graupel growth and its trajectory is analysed by sensitivity experiments based on the amplitude of the forced lifting, and initial graupel radius, density and cloud droplet concentration for the forced lifting initiation time derived from the model and the forced lifting duration time that agreed with observations. In particular, the sensitivity analysis was carried out for the forced lifting initiation and duration times.

It is shown that for large values of the forced lifting amplitudes, the residence time of the graupel within cloud and the final graupel radius may be significantly larger compared with those in the non‐forced case. The residence time in a cloud can also be significantly larger for the smallest amplitude, whereas the final radius is rather insensitive owing to oscillations around the melting level. For some cases the forced lifting causes recycling inside the updraft, contrary to the results of previous non‐forced numerical models. The recycling mechanism is sensitive to the forced lifting duration time and the time interval between the graupel pocket injection in cloud and the initiation of the forced lifting. Initially the observed recycling mechanism is a consequence of the periodic forced lifting mechanism, but then combines with recycling of the Pflaum type (1980).  相似文献   

Numerical simulation of Cb cloud vorticity     

Mladjen &#x;uri&#x;  Dejan Janc  Vladan Vu kovi&#x; 《Atmospheric Research》2007,83(2-4):427-434

Vertical vorticity characteristics within individual cumulonimbus (Cb) cloud moving over complex terrain are investigated by cloud-resolving mesoscale model. Orography impact on vorticity is recognized by comparison of its characteristics within the storm moving over flat terrain under the same other conditions. In present study, two cases are considered: complex terrain case (referred to as CT case) and flat terrain case (referred to as FT case). A sensitivity study shows that orographical effects on vorticity are important. Main findings are:

– For CT case vortices produced by convective tilting of horizontal vortices are closer to each other and more stretched in form owing to valley configuration. The vortex with positive vorticity is mainly stronger in magnitude compared to its negative counterpart.

– Magnitudes of vorticities for CT case are greater at lowest levels and initial time intervals compared to those for FT case.

– For CT case the vortices with opposite signs of vorticity produced by precipitation appear later than in FT case. Their duration is shorter and they are weaker in intensity compared to those formed within a cloud over flat terrain.

– Complex terrain intensifies the splitting of simulated cloud.

Indications of competition between non-indigenous round goby and native flounder in the Baltic Sea     

Karlson  Agnes M. L.; Almqvist  Gustaf; Skora  Krzysztof E.; Appelberg  Magnus 《ICES Journal of Marine Science》2007,64(3):479-486

  相似文献   

EPR and magnetism of the nanostructured natural carbonaceous material shungite     

Maria Aldona Augustyniak-Jabłokow  Yurii V. Yablokov  Bartłomiej Andrzejewski  Wojciech Kempiński  Szymon Łoś  Krzysztof Tadyszak  Mikhail Y. Yablokov  Valentin A. Zhikharev 《Physics and Chemistry of Minerals》2010,37(4):237-247

The X-band EPR and magnetic susceptibility in the temperature range 4.2–300 K study of the shungite-I, natural nanostructured material from the deposit of Shunga are reported. Obtained results allow us to assign the EPR signal to conduction electrons, estimate their number, N _P, and evaluate the Pauli paramagnetism contribution to shungite susceptibility. A small occupation (~5%) of the localized nonbonding π states in the zigzag edges of the open-ended graphene-like layers and/or on σ (sp ^2+x ) orbitals in the curved parts of the shungite globules has been also revealed. The observed temperature dependence of the EPR linewidth can be explained by the earlier considered interaction of conduction π electrons with local phonon modes associated with the vibration of peripheral carbon atoms of the open zigzag-type edges and with peripheral carbon atoms cross-linking different nanostructures. The relaxation time T ₂ and diffusion time T _D are found to have comparable values (2.84 × 10⁻⁸ and 1.73 × 10⁻⁸ s at 5.2 K, respectively), and similar dependence on temperature. The magnetic measurements have revealed the suppression of orbital diamagnetism due to small amount of large enough fragments of the graphene layers.  相似文献   

The spatial distribution of deposited seeding material in the Earth boundary layer during weather modification     

M. ?uri?  D. Janc 《Meteorology and Atmospheric Physics》2012,118(1-2):31-36

Cloud seeding projects may have the time scale of half a century and cover the planetary-scale surface. Such activities among the positive also have negative consequences that include environmental pollution. Year after year cloud seeding over certain areas could produce large amounts of seeding agents washed out in precipitation. The sampling of these deposits is therefore important, but not applied in large space and time scales due to a high cost. As an alternative, the cloud seeding project measurements may be used for finding the deposit spatial pattern and locations of its maximum. In this study, we established the method for finding the spatial distribution of deposited silver iodide over a selected area after hail suppression using the observed characteristics of seeded hailstorms. The estimation of the silver iodide deposit maximum is 155?μg?m^?2 during a 6-year period. Our findings agree well with those obtained from sampling silver content in precipitation during the other convective cloud seeding experiments. On the other hand, our method gives an answer of where to place the samplers, and hence more detailed chemical analysis and monitoring can be done in the future. The proposed methodology may be applied for any other target area and cloud seeding scenario.  相似文献   

Dependence of accumulated precipitation on cloud drop size distribution     

Mladjen Ćurić  Dejan Janc  Katarina Veljović 《Theoretical and Applied Climatology》2010,102(3-4):471-481

Convective precipitation is the main cause of extreme rainfall events in small areas. Its primary characteristics are both large spatial and temporal variability. For this reason, the monitoring of accumulated precipitation fields (liquid and solid components) at the surface is difficult to carry out through the use of rain gauge networks or remote-sensing observations. Alternatively, numerical models seem to be the most powerful tool in simulating convective precipitation for various analyses and predictions. Due to a lack of comparisons between modelled and observed precipitation characteristics over a long period of time, we focus our research on comparisons between observations and three model samples of accumulated convective precipitation over a particular study area. We use a numerical cloud model with two model schemes involving the unified Khrgian–Mazin size distribution of cloud drops and a model scheme involving a monodisperse cloud droplet spectrum and the Marshall–Palmer size distribution for raindrops, respectively. For comparison, we have selected a study area with a sounding site. Our analysis shows that the model version with the Khrgian–Mazin size distribution exhibits a better agreement with the observed mean, median and range of extreme values of accumulated convective precipitation. Model simulations with the Khrgian–Mazin size distribution most closely match observations, with a correlation coefficient of 0.91. Use of the Marshall–Palmer size distribution, on the other hand, systemically underestimates the observed precipitation and has the lowest correlation coefficient among the methods, 0.83. Such an investigation is crucial to improve predictions of accumulated convective precipitation for various climatological and hydrological analyses and predictions.  相似文献