| 1. |
- Bures, Miroslav, et al.
(author)
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PatrIoT: IoT Automated Interoperability and Integration Testing Framework
- 2021
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In: IEEE International Conference on Software Testing Verification and Validation. - : IEEE. ; , s. 454-459
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Conference paper (peer-reviewed)abstract
- With the rapid growth of the contemporary Internet of Things (IoT) market, the established systems raise a number of concerns regarding the reliability and the potential presence of critical integration defects. In this paper, we present a PatrIoT framework that aims to provide flexible support to construct an effective IoT system testbed to implement automated interoperability and integration testing. The framework allows scaling from a pure physical testbed to a simulated environment using a number of predefined modules and elements to simulate an IoT device or part of the tested infrastructure. PatrIoT also contains a set of reference example testbeds and several sets of example automated tests for a smart street use case.
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| 2. |
- Büntgen, Ulf, et al.
(author)
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Recent European drought extremes beyond Common Era background variability
- 2021
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In: Nature Geoscience. - : Springer Science and Business Media LLC. - 1752-0894 .- 1752-0908. ; 14:4, s. 190-196
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Journal article (peer-reviewed)abstract
- Europe's recent summer droughts have had devastating ecological and economic consequences, but the severity and cause of these extremes remain unclear. Here we present 27,080 annually resolved and absolutely dated measurements of tree-ring stable carbon and oxygen (delta C-13 and delta O-18) isotopes from 21 living and 126 relict oaks (Quercus spp.) used to reconstruct central European summer hydroclimate from 75 bce to 2018 ce. We find that the combined inverse delta C-13 and delta O-18 values correlate with the June-August Palmer Drought Severity Index from 1901-2018 at 0.73 (P < 0.001). Pluvials around 200, 720 and 1100 ce, and droughts around 40, 590, 950 and 1510 ce and in the twenty-first century, are superimposed on a multi-millennial drying trend. Our reconstruction demonstrates that the sequence of recent European summer droughts since 2015 ce is unprecedented in the past 2,110 years. This hydroclimatic anomaly is probably caused by anthropogenic warming and associated changes in the position of the summer jet stream. European summer droughts in recent years are anomalously severe compared with those of the previous 2,000 years, according to a synthesis of annually resolved tree-ring carbon and oxygen isotope records.
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| 3. |
- Büntgen, Ulf, et al.
(author)
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Tree-Ring Amplification of the Early Nineteenth-Century Summer Cooling in Central Europe
- 2015
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In: Journal of Climate. - 0894-8755 .- 1520-0442. ; 28:13, s. 5272-5288
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Research review (peer-reviewed)abstract
- Annually resolved and absolutely dated tree-ring chronologies are the most important proxy archives to reconstruct climate variability over centuries to millennia. However, the suitability of tree-ring chronologies to reflect the “true” spectral properties of past changes in temperature and hydroclimate has recently been debated. At issue is the accurate quantification of temperature differences between early nineteenth-century cooling and recent warming. In this regard, central Europe (CEU) offers the unique opportunity to compare evidence from instrumental measurements, paleomodel simulations, and proxy reconstructions covering both the exceptionally hot summer of 2003 and the year without summer in 1816. This study uses 565 Swiss stone pine (Pinus cembra) ring width samples from high-elevation sites in the Slovakian Tatra Mountains and Austrian Alps to reconstruct CEU summer temperatures over the past three centuries. This new temperature history is compared to different sets of instrumental measurements and state-of-the-art climate model simulations. All records independently reveal the coolest conditions in the 1810s and warmest after 1996, but the ring width–based reconstruction overestimates the intensity and duration of the early nineteenth-century summer cooling by approximately 1.5°C at decadal scales. This proxy-specific deviation is most likely triggered by inflated biological memory in response to reduced warm season temperature, together with changes in radiation and precipitation following the Tambora eruption in April 1815. While suggesting there exists a specific limitation in ring width chronologies to capture abrupt climate perturbations with increased climate system inertia, the results underline the importance of alternative dendrochronological and wood anatomical parameters, including stable isotopes and maximum density, to assess the frequency and severity of climatic extremes.
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| 4. |
- Čejka, Tomáš, et al.
(author)
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Predicted climate change will increase the truffle cultivation potential in central Europe
- 2020
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1
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Journal article (peer-reviewed)abstract
- Climate change affects the distribution of many species, including Burgundy and Perigord truffles in central and southern Europe, respectively. The cultivation potential of these high-prized cash crops under future warming, however, remains highly uncertain. Here we perform a literature review to define the ecological requirements for the growth of both truffle species. This information is used to develop niche models, and to estimate their cultivation potential in the Czech Republic under current (2020) and future (2050) climate conditions. The Burgundy truffle is already highly suitable for cultivation on similar to 14% of agricultural land in the Czech Republic (8486 km(2)), whereas only similar to 8% of the warmest part of southern Moravia are currently characterised by a low suitability for Perigord truffles (6418 km(2)). Though rising temperatures under RCP8.5 will reduce the highly suitable cultivation areas by 7%, the 250 km(2) (3%) expansion under low-emission scenarios will stimulate Burgundy truffles to benefit from future warming. Doubling the moderate and expanding the highly suitable land by 352 km(2) in 2050, the overall cultivation potential for Perigord truffles will rise substantially. Our findings suggest that Burgundy and Perigord truffles could become important high-value crops for many regions in central Europe with alkaline soils. Although associated with uncertainty, long-term investments in truffle cultivation could generate a wide range of ecological and economic benefits.
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| 5. |
- Fronzek, Stefan, et al.
(author)
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Classifying multi-model wheat yield impact response surfaces showing sensitivity to temperature and precipitation change
- 2018
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In: Agricultural Systems. - : Elsevier BV. - 0308-521X. ; 159, s. 209-224
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Journal article (peer-reviewed)abstract
- Crop growth simulation models can differ greatly in their treatment of key processes and hence in their response to environmental conditions. Here, we used an ensemble of 26 process-based wheat models applied at sites across a European transect to compare their sensitivity to changes in temperature (-2 to +9°C) and precipitation (-50 to +50%). Model results were analysed by plotting them as impact response surfaces (IRSs), classifying the IRS patterns of individual model simulations, describing these classes and analysing factors that may explain the major differences in model responses.The model ensemble was used to simulate yields of winter and spring wheat at four sites in Finland, Germany and Spain. Results were plotted as IRSs that show changes in yields relative to the baseline with respect to temperature and precipitation. IRSs of 30-year means and selected extreme years were classified using two approaches describing their pattern.The expert diagnostic approach (EDA) combines two aspects of IRS patterns: location of the maximum yield (nine classes) and strength of the yield response with respect to climate (four classes), resulting in a total of 36 combined classes defined using criteria pre-specified by experts. The statistical diagnostic approach (SDA) groups IRSs by comparing their pattern and magnitude, without attempting to interpret these features. It applies a hierarchical clustering method, grouping response patterns using a distance metric that combines the spatial correlation and Euclidian distance between IRS pairs. The two approaches were used to investigate whether different patterns of yield response could be related to different properties of the crop models, specifically their genealogy, calibration and process description.Although no single model property across a large model ensemble was found to explain the integrated yield response to temperature and precipitation perturbations, the application of the EDA and SDA approaches revealed their capability to distinguish: (i) stronger yield responses to precipitation for winter wheat than spring wheat; (ii) differing strengths of response to climate changes for years with anomalous weather conditions compared to period-average conditions; (iii) the influence of site conditions on yield patterns; (iv) similarities in IRS patterns among models with related genealogy; (v) similarities in IRS patterns for models with simpler process descriptions of root growth and water uptake compared to those with more complex descriptions; and (vi) a closer correspondence of IRS patterns in models using partitioning schemes to represent yield formation than in those using a harvest index.Such results can inform future crop modelling studies that seek to exploit the diversity of multi-model ensembles, by distinguishing ensemble members that span a wide range of responses as well as those that display implausible behaviour or strong mutual similarities.
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| 6. |
- Klima, Matej, et al.
(author)
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Selected Code-Quality Characteristics and Metrics for Internet of Things Systems
- 2022
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In: IEEE Access. - : IEEE. - 2169-3536. ; 10, s. 46144-46161
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Journal article (peer-reviewed)abstract
- Software code is present on multiple levels within current Internet of Things (IoT) systems. The quality of this code impacts system reliability, safety, maintainability, and other quality aspects. In this paper, we provide a comprehensive overview of code quality-related metrics, specifically revised for the context of IoT systems. These metrics are divided into main code quality categories: Size, redundancy, complexity, coupling, unit test coverage and effectiveness, cohesion, code readability, security, and code heterogeneity. The metrics are then linked to selected general quality characteristics from the ISO/IEC 25010:2011 standard by their possible impact on the quality and reliability of an IoT system, the principal layer of the system, the code levels and the main phases of the project to which they are relevant. This analysis is followed by a discussion of code smells and their relation to the presented metrics. The overview presented in the paper is the result of a thorough analysis and discussion of the author’s team with the involvement of external subject-matter experts in which a defined decision algorithm was followed. The primary result of the paper is an overview of the metrics accompanied by applicability notes related to the quality characteristics, the system layer, the level of the code, and the phase of the IoT project.
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| 7. |
- Trnka, Miroslav, et al.
(author)
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Priority questions in multidisciplinary drought research
- 2018
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In: Climate Research (CR). - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 75, s. 241-260
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Journal article (peer-reviewed)abstract
- Addressing timely and relevant questions across amultitude of spatio-temporal scales,state-of-the-art interdisciplinary drought research will likely increase in importance under projectedclimate change. Given the complexity of the various direct and indirect causes and consequences of adrier world, scientific tasks need to be coordinated efficiently. Drought-related research endeavorsranging from individual projects to global initiatives therefore require prioritization. Here, wepresent 60 priority questions for optimizing future drought research. This topical catalogue reflectsthe experience of 65 scholars from 21 countries and almost 20 fields of research in both naturalsciences and the humanities. The set of drought-related questions primarily covers drought monitoring,impacts, forecasting, climatology, adaptation, as well as planning and policy. The questionshighlight the increasingly important role of remote sensing techniques in drought monitoring, importanceof drought forecasting and understanding the relationships between drought parametersand drought impacts, but also challenges of drought adaptation and preparedness policies.
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