384 research outputs found
Intrusion Detection via Artificial Immune System: a Performance-based Approach
No full textIn this paper, we discuss the design and engineering of a biologically-inspired, host-based intrusion detection system to protect computer networks. To this end, we have implemented an Artificial Immune System (AIS) that mimics the behavior of the biological adaptive immune system. The proposed AIS, consists of a number of running artificial white blood cells, which search, recognize, store and deny anomalous requests on individual hosts. The model monitors the system through analysing the set of parameters to provide a general information on its state — ill or not. When some parameters are discovered to have anomalous values, then the artificial immune system takes a proper action. To prove the effectiveness of the suggested model, an exhaustive test on the AIS is conducted, using a server running Apache, Mysql and OpenSSH, and results are reported. Four types of attacks were tested: remote buffer overflow, Distributed Denial of Service (DDOS), port scanning, and dictionary-attack. The test proved that our definition of self/non-self system components is quite effective in protecting host-based systems
Advancing Transparency: Connecting glass with heat – An experimental approach to the implementation of heat bonding into glass connection design for structural applications
No full textGlass is transparent and that differentiates it from most other building materials. As a result it has played a significant role in the development of architecture, given that its use is not only driven by its functionality as a protective layer, but by its ability to transmit light and hence define spaces. The use of glass has typically brought designers, engineers and builders to the limits of their abilities, whether this was driven by the processing and handling of the material, or the limitation in the understanding of its design capacity. The transparency of the material is of incredible value but it also poses challenges when working with glass; The way it is connected is always visible. As a result, the connections and connectivity of glass are one of the most important considerations when designing with it, both technically and architecturally and in particular for structural applications. In the past century, glass has increasingly been used as a structural component. However its inherent brittleness typically still requires opaque metal connections to transfer load. These connections define contemporary glass architecture – firstly, because they are immediately apparent in a transparent structure and, secondly, as they are part of the engineering design language. However, designers and architects are still aiming to increase the transparency of glass enclosures and structures, leading to a demand to further reduce the visibility of structural connections within the glass. This research aims to address the connectivity of glass through experimental testing of heat bonded glass-glass connections that form a fully transparent atomic bond. Applications for transparent connections are addressed through case studies that explore various novel transparent bonding techniques.A+BE I Architecture and the Built Environment No 9 (2022)Design of Construtio
Biologically Inspired Methods for Organizing Distributed Services on Sensor Networks
No full textWe propose to make use of a completely distributed way of implementing OS services for wireless sensor networks (WSN). I.e. instead of having an instance of the OS on each node of a WSN the services of the OS are distributed over the WSN. Of course this approach implies specific challenges. Two of them are discussed in the paper: Migration of services to nodes such that the overall communication costs are minimized and forming clusters with the tendency to concentrate service requests inside the clusters and at the same time minimizing intra-cluster communication. For both problems biologically inspired solutions are discussed. Service migration is mapped on an Ant Colony Optimization (ACO) technique while as a clustering heuristics Division of Labor in swarms of social insects is used
Deforestation effects on Amazon forest resilience
No full textThrough vegetation-atmosphere feedbacks, rainfall reductions as a result of Amazon deforestation could reduce the resilience on the remaining forest to perturbations and potentially lead to large-scale Amazon forest loss. We track observation-based water fluxes from sources (evapotranspiration) to sinks (rainfall) to assess the effect of deforestation on continental rainfall. By studying 21st century deforestation scenarios, we show that deforestation can reduce dry season rainfall by up to 20% far from the deforested area, namely, over the western Amazon basin and the La Plata basin. As a consequence, forest resilience is systematically eroded in the southwestern region covering a quarter of the current Amazon forest. Our findings suggest that the climatological effects of deforestation can lead to permanent forest loss in this region. We identify hot spot regions where forest loss should be avoided to maintain the ecological integrity of the Amazon forest
Integrate Online Model Checking into Distributed Reconfigurable System on Chip with Adaptable OS Services
No full textInternational audienceThis paper presents a novel flexible, dependable, and reliable operating system design for distributed reconfigurable system on chip. The dependability and reliability are achieved by integrating online model checking technique. Each OS service has different implementations which are further partitioned into small blocks. This operating system design allows the OS service to be adapted at runtime according to the given resource requirements and response time. Such adaptable services may be required by real time safety-critical applications. The flexibility introduced in executing adaptable OS services also gives rise to a potential safety problem. Thus, online model checking is integrated to the operating system so as to improve the dependability, reliability, and fault tolerance of these adaptable OS services
The DASE Tool: An Environment for the Development of Real-Time Applications
No full textIn this paper we discuss some design issues related to the handling of timing constraints in embedded systems and present a tool for the analysis of timing constraints at the architectural design level. Most design tools for real-time applications do not perform any kind of real-time analysis and do not allow the definition of explicit timing constraints. Our tool is aimed at real-time schedulability and performance analysis. It guides the decomposition of the application architecture into a set of hierarchical abstractions representing the active components and the cooperation among them (messages and/or use of shared resources). Deadlines can be specified between any couple of events. The real-time schedulability analysis requires a sufficiently accurate description of the (hardware) architecture, the mapping of the software components on the application nodes and the choice of the resource management algorithms
Dynamisch rekonfigurierbare Hardware als Basistechnologie für intelligente technische Systeme
No full textKorf S, Sievers G, Ax J, et al. Dynamisch rekonfigurierbare Hardware als Basistechnologie für intelligente technische Systeme. In: Gausemeier J, Dumitrescu R, Rammig F, Trächtler A, eds. Proceedings Wissenschaftsforum 2013 Intelligente Technische Systeme. HNI-Verlagsschriftenreihe. Vol 310. Paderborn: Heinz-Nixdorf-Inst., Univ. Paderborn; 2013: 79-90
Component case study of a self-optimizing RCOS/RTOS system. A reconfigurable network service
No full textGriese B, Oberthür S, Porrmann M. Component case study of a self-optimizing RCOS/RTOS system. A reconfigurable network service. In: Rettberg A, Zanella MC, Rammig FJ, eds. From Specification to Embedded Systems Application. IFIP On-Line Library in Computer Science . Vol 184. Boston, MA: Springer; 2005: 267-277.In highly dynamic scenarios a real-time communication/real-time operating system
(RCOS/RTOS), which can fulfill all upcoming demands of the application,
is normally very extensive. These RCOS/RTOS systems are heavy-weighted and
produce much overhead. System resources for an application or a system service
are often reserved for worst-case scenarios and are not usable for other applications.
We present a self-optimizing RCOS/RTOS with an integrated flexible
resource management. Our RCOS/RTOS adapts its services to the application
demands and redistributes temporarily unused resources to other applications
under hard real-time conditions. The benefit of our system is shown by means
of a self-optimizing communication service. The main building block of this
communication service is a reconfigurable dual-port Ethernet switch. Using dynamically
reconfigurable hardware to implement the switch enables an adaption
of the switch to changing requirements during run-time
Self-amplified Amazon forest loss due to vegetation-atmosphere feedbacks
No full textReduced rainfall increases the risk of forest dieback, while in return forest loss might intensify regional droughts. The consequences of this vegetation–atmosphere feedback for the stability of the Amazon forest are still unclear. Here we show that the risk of self-amplified Amazon forest loss increases nonlinearly with dry-season intensification. We apply a novel complex-network approach, in which Amazon forest patches are linked by observation-based atmospheric water fluxes. Our results suggest that the risk of self-amplified forest loss is reduced with increasing heterogeneity in the response of forest patches to reduced rainfall. Under dry-season Amazonian rainfall reductions, comparable to Last Glacial Maximum conditions, additional forest loss due to self-amplified effects occurs in 10–13% of the Amazon basin. Although our findings do not indicate that the projected rainfall changes for the end of the twenty-first century will lead to complete Amazon dieback, they suggest that frequent extreme drought events have the potential to destabilize large parts of the Amazon forest
Code associated with: Hansen, W.D., N.B Schwartz, A.P. Williams, K. Albrich, L.M. Kueppers, A. Rammig, C.P.O. Reyer, A.C. Staver, and R. Seidl. Global forests are influenced by legacies of past inter-annual temperature variability.
No full textThese files are associated with,
Hansen, W.D., N.B Schwartz, A.P. Williams, K. Albrich, L.M. Kueppers, A. Rammig, C.P.O. Reyer, A.C. Staver, and R. Seidl. 2022. Global forests are influenced by legacies of past inter-annual temperature variability. Environmental Research:Ecology 1, 011001.
Abstract:
Inter-annual climate variability (hereafter climate variability) is increasing in many forested regions with climate change. This variability could have larger near-term impacts on forests than decadal shifts in mean climate, but how forests will respond remains poorly resolved, particularly at broad scales. Individual trees and even forest communities often have traits and ecological strategies – the legacies of exposure to past variable conditions – that confer tolerance to subsequent climate variability. However, whether local legacies also shape global forest responses is unknown. Our objective was to assess how past and current climate variability influences global forest productivity. We hypothesized forests exposed to large climate variability in the past would better tolerate current climate variability than forests where past climate was relatively stable. We used historical (1950-1969) and contemporary (2000-2019) temperature, precipitation, and vapor pressure deficit and the remotely-sensed Enhanced Vegetation Index to quantify how historical and contemporary climate variability relate to patterns of contemporary forest productivity. Consistent with our hypothesis, forests exposed to large temperature variability in the past were more tolerant of contemporary temperature variability than forests where past temperatures were less variable. Forests were 19-fold less sensitive to contemporary temperature variability where historical inter-annual temperature variability was 0.66°C (2 standard deviations) greater than the global average historical temperature variability. We also found that larger increases in temperature variability between the two study periods often eroded the tolerance conferred by legacy effects of historical temperature variability. However, the hypothesis was not supported in the case of precipitation and vapor pressure deficit variability, potentially due to physiological tradeoffs inherent in how trees cope with dry conditions. We conclude that sensitivity of forest productivity to imminent increases in temperature variability may be partially predictable based on legacies of past conditions.
File list:
Processing_climate_data_final_1-21-2021.Rmd
Processing_EVI_NDVI_final_1-20-2021.Rmd
Processing_Modis_Landcover_final_1-20-2021.Rmd
Priming_analysis_sd_12-16-2021.Rmd
Spatial_runs_cluster_modern.1-30-2021.R
Spatial_runs_cluster_past.1-30-2021.R
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