Abstract

Efficient management of natural disasters impose great research challenges to the current environmental crisis management systems in terms of both architecture and services. This is mainly due to the fact that a large amount of geospatial content is usually distributed, non-compliant to standards, and needs to be transmitted under a QoS guaranteed framework to support effective decision making either in case of an emergency or in advance planning. Incorporating real time capabilities in Web services, both in terms of dynamic configuration and service selection, is an open research agenda. The things get worst in geospatial context due to the huge amount of data transmitted from distributed sensors under heterogeneous platforms, making the need of synchronization an important issue. In this paper, we propose a flexible service oriented architecture for planning and decision support in environmental crisis management. The suggested architecture uses real time geospatial data sets and 3D presentation tools, integrated with added-value services, such as simulation models for assisting decision making in case of emergency. The proposed architectural framework goes beyond integration and presentation of static spatial data, to include real time middleware that is responsible for selecting the most appropriate method of the available geospatial content and service in order to satisfy the QoS requirements of users and/or application. A case study of a complete, real world implementation of the suggested framework dealing with forest fire crisis management system is also presented. FGCS - International Journal of Future Generation Computer Systems.

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Abstract

Software development has been acknowledged as a complicated problem-solving activity done in a complex, multi-dimensional space. People actively involved in software development need support in understanding and documenting not only the description of the software developed, but also the problem domain and the reasons behind decisions taken during evolution. Development methods do not provide such support, and researchers begin to explore the recording of reasoning in specific phases of software evolution. Several data models have been presented, aiming to support developers by maintaining a repository of deliberation elements of decisions taken during development; these models are usually supported by a special CASE tool that can be classified as a Software decision management system. Using experience gained in the development of large-scale applications in an industrial environment, and experimenting with prototype software design decision management systems, we introduce a conceptual logic-based meta-model that integrates software evolution process modelling with deliberation representation and decision factors. Our model enhances existing models by providing support throughout the whole software evolution, by capturing assumptions as real-world reasoning elements, and by maintaining a Knowledge Base of decision-making factors. A prototype Software Evolution Decision Support System is also presented in this paper.

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Abstract

As human constructions, networks and activities become more complex and interconnected, hazards may create cascading effects among structures and networks of any kind; in order to be as effective as possible, risk analysis research needs to consider there dependencies. In this respect, we need a common application-agnostic information infrastructure that integrates all kinds of relevant data and computational services, in a way that makes them available in a context of shared scenarios among researchers from different disciplines. Such an infrastructure is introduced in this paper as an information system architecture that satisfies requirements for sharing geo-referenced data and services. A graph for representing localized cascading effect scenarios for sharing scenarios and pipelining data processed by different disciplines is introduced. Experience from past relevant work for sharing geo-spatial data in Switzerland is also presented.

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Abstract

Volunteered Geographic Information (VGI) has been used in various scientific domains and applications. Surveying Engineering is a field that has not yet exploited concepts like data and service sharing and reuse. This paper aims to suggest a framework that will support data sharing in Surveying Engineering by creating an online spatio-temporal information repository for land surveying projects. A data model to meet the needs for Surveying Engineering applications and accuracy requirements is introduced to facilitate the sharing of VGI information among Surveying Engineers. A fully functional prototype system has been developed and used to apply the proposed methodology in a large scale study undertaken by the Greek Ministry of Culture which involves the mapping of the historic center of Athens as part of the Archaeological Cadastre project. Results coming from data analysis indicate a substantial (~60 %) error reduction and also significant productivity raise (~25 %), while at the same time, the collected data are structured and saved in an online database, accessible by community users—professional Surveying Engineers who can in turn contribute to further improve the available data and services according to the principles of VGI applications.

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Abstract

In recent years, Wireless Sensor Networks (WSNs) have rapidly evolved and now comprise a powerful tool in monitoring and observation of the natural environment, among other fields. The use of WSNs is critical in early warning systems, which are of high importance today. In fact, WSNs are adopted more and more in various applications, e.g. for fire or deformation detection. The optimum deployment of sensors is a multi-dimensional problem, which has two main components; network and positioning approach. Although lots of work has dealt with the issue, most of it emphasizes on mere network approach (communication, energy consumption) and not on the topography (positioning) of the sensors in achieving ideal geometry. In some cases, it is hard or even impossible to achieve perfect geometry in nodes’ deployment. The ideal and desirable scenario of nodes arranged in square or hexagonal grid would raise extremely the cost of the network, especially in unfriendly or hostile environments. In such environments the positions of the sensors have to be chosen among a list of possible points, which in most cases are randomly distributed. This constraint has to be taken under consideration during the WSN planning. Full geographical coverage is in some applications of the same, if not of greater, importance than the network coverage. Cost is a crucial factor at network planning and given that resources are often limited, what matters, is to cover the whole area with the minimum number of sensors. This paper suggests a deployment method for nodes, in large scale and high density WSNs, based on Centroidal Voronoi Tessellation (CVT). It approximates the solution through the geometry of the random points and proposes a deployment plan, for the given characteristics of the study area, in order to achieve a deployment as near as possible to the ideal one.

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Abstract

In this paper, we analyze the extended grid of cells topology with overlaps and its enhancement, with the aim to reduce cost and increase the response time of a monitoring network, which mainly acts as an early warning system. The proposed topology meets the specific problem requirements of large scale area coverage with high density sensor networks and provides a feasible and an efficient solution to it. This topology is applied in an expandable way, taking into consideration simulation results. The proposed network architecture combines the node signal attenuation with its localization for redundancy sake. The topology resembles the cellular phone network architecture, yet it is deployed according to WSN characteristics and limitations. It constitutes the fundamental – theoretical topology approach upon which elevation and trees location will be taken into consideration in the forthcoming research. As a result, an appropriate WSN topology with increased efficiency and reduced cost per particular area is proposed. What is more, estimations and quantitative analysis regarding network devices and installation procedure are performed.

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Abstract

Large Scale WSN deployment is considered to be a very complex operation in terms of both efficiency and cost. Sensor cost has never been low, not even today, though at the same time the large areas to be covered call for a huge number of wireless sensors. The complexity escalates when it comes to forest areas, as such areas consist of an assortment of different landscapes and terrains and therefore, they cannot be modeled in detail. In this paper a first approach to forest area classification is attempted, so that simulation models can describe the attenuation of the alarming signal and the corresponding connectivity in the classified area. A number of models produced by Shawn simulator are provided, for forest areas with dense and scant plantation of trees. The model that best converges to the real experiment metrics per area is determined and is therefore referenced as “the model” for the specific classified area. Provided the fact that the simulation model per classified area is granted, a step to the optimal sensor topology is performed, as the connectivity and path loss problem is mainly and in most cases linearly confined to distance variations. Recent Patents are also covered. The simulation models along with optimal sensor topologies can become a guide in Large Scale WSN deployment primarily for the areas classified as “dense” and “scant” in terms of plantation, with the aim to deploy a reliable WSN for environmental purposes.

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Abstract

Environment protection and preservation is an in season issue today, more than ever before. It has become a critical concern as the climate change threatens the sustainability of human societies; in this context exploitation of any technological advance in protecting the environment is more than welcome. Wireless sensor network applications appear as a promising technology, very helpful to many environmental applications. We compare the results of a common simulation scenario produced by the use of three well-known simulators. These results are also matched against measurements taken out of real world WSN measurements and monitoring in a forest environment, and specifically in a forest area with high vegetation density. In this context, conclusions and assessments are attempted on the maturity of these simulation and visualization tools for large-scale WSN deployments in such environments.

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