Hellenic Military Academy

About: Hellenic Military Academy is a education organization based out in Voula, Greece. It is known for research contribution in the topics: Computer science & Complex space. The organization has 36 authors who have published 97 publications receiving 541 citations.

The many facets of Poincare recurrence theorem of the logistic map

Abstract: Purpose – The purpose of this paper is to illustrate the many aspects of Poincare recurrence time theorem for an archetype of a complex system, the logistic map.Design/methodology/approach – At the beginning of the twentieth century, Poincare's recurrence theorem had revolutionized modern mechanics and statistical physics. However, this theorem did not attract considerable attention, at least from a numerical and computational point of view. In a series of relatively recent papers, Balakrishnan, Nicolis and Nicolis have addressed the recurrence time problem in a firm basis, introducing notation, theory, and numerical studies. Motivated by this call, the paper proposes to illustrate the many aspects of Poincare recurrence time theorem for an archetype of a complex system, the logistic map. The authors propose here in different tests and computations, each one illuminating the many aspects of the problem of recurrence. The paper ends up with a short discussion and conclusions.Findings – In this paper, the a...

Abductive Reasoning in 2D Geospatial Problems

Abstract: Spatial Analysis has been using so far Spatial Reasoning, but it mainly confines itself to spatial statistical analysis of the observed phenomena searching for pattern analysis, geostatistical indices etc. Researchers Shakarian P., Subrahmanian V. S., and Sapino M. L. are the first who examined the possibility of extending Spatial Analysis in finite, discretized, 2D space with the incorporation of Abductive Reasoning, which originates from the cognitive field of Artificial Intelligence, and is related to the analysis of causation of the phenomena under consideration. The new class of Geospatial Problems was named point-based Geospatial Abduction Problems (or point-based GAPs). They primarily focused on a version of GAPs named Improvised Explosive Devices Cache Detection Problem, or IED Cache Detection Problem, and they carried out experiments with real-world data from Baghdad. In this paper a technique which reduces the total computational cost in any version of point-based GAPs will be introduced, and an exact algorithm for the natural optimization problem of point-based GAPs will be presented along with its computational complexity results.

Region-Based Watermarking for Images

Abstract: Plain rotation, scaling, and/or translation (RST) of an image can lead to loss of watermark synchronization and thus authentication failure with standard techniques. The block-based approaches in particular, albeit strong against frequency and cropping attacks, are sensitive to geometric distortions due to the need for repositioning the blocks’ rectangular grid of reference. In this paper, we propose a block-based approach for watermarking image objects in a way that is invariant to RST distortions. With the term image object we refer to semantically contiguous parts of images that have a specific contour boundary. The proposed approach is based on shape information since the watermark is embedded in image blocks, the location and orientation of which are defined by Eulerian tours that are appropriately arranged in layers, around the object’s robust skeleton. The object’s robust skeleton is derived by its boundary after applying an extraction technique and not only is invariant to RST transformations but also to cropping, clipping, and other common deformation attacks, difficult to defend with current methods. Experiments using standard benchmark datasets demonstrate the advantages of the proposed scheme in comparison to alternative state-of-the-art methods.

Heterogeneity in Supply Chain Management: An Efficiency Approach

Abstract: Today’s organizations struggle for efficiency and effectiveness. Strategies involving collaboration between actors and integration of activity chains are reliant of factors that firms do not have direct ownership and control over. This has implications for strategizing, setting the goals and measuring performance. Efficiency and effectiveness are often used to describe performance. From a resource dependence perspective efficiency is defined as an internal standard of performance and effectiveness as an external standard of fit to various demands. This chapter attempts through a literature survey to search the main pillars and the determinant factors for efficiency in supply chain management and to present the effects in the competitiveness and the efficient level for an economy.