Search results for "76"
showing 10 items of 2584 documents
Palaeoentomological study of the lacustrine oil-shales of the lower Miocene San Chils locality (Ribesalbes-Alcora Basin, Castellón province, Spain)
2020
For the first time, the study of the fossil record present in laminated bituminous dolostones from the San Chils locality, lower Miocene in age (ca. 19 Ma), located at the Ribesalbes-Alcora Basin, is addressed. The identification of 11 families and three genera belonging to six insect orders (Orthoptera, Thysanoptera, Hemiptera, Coleoptera, Hymenoptera and Diptera) has been carried out. Furthermore, ephippia of ladoceran crustaceans, one bird feather, vertebrate coprolites and plant remains have been found. The San Chils palaeodiversity has been compared to that of La Rinconada, a similar outcrop in the same basin and depositional unit. Both localities correspond to lacustrine deposits and …
A long-snouted late Eifelian arthrodire from Aragon (Spain)
2021
Carolowilhelmina geognostica Carls, 1995 is a large arthrodire (Placodermi) from the Tortodus kockelianus Conodont Zone, late Eifelian, in the Eastern Iberian Cordillera in southern Aragon. The somewhat incomplete but articulated skull is preserved, showing a long tubular rostral plate, very small postnasal plates, low toothless inferognathals, and a small, slender and flat parasphenoid. Supraorbital and central sensory lines meet their antimeres at the midline of the skull, forming a straight double line. Lines along the ventral surface of the rostral plate probably belong to the suborbital branches of the infraorbital sensory lines. The combination of characters of Carolowilhelmina points…
Nonlinear Feedback Control and Stability Analysis of a Proof-of-Work Blockchain
2017
In this paper a novel feedback controller and stability analysis of a blockchain implementation is developed by using a control engineering perspective. The controller output equals the difficulty adjustment in the mining process while the feedback variable is the average block time over a certain time period. The computational power (hash rate) of the miners is considered a disturbance in the model. The developed controller is tested against a simulation model with constant disturbance, step and ramp responses as well as with a high-frequency sinusoidal disturbance. Stability and a fast response is demonstrated in all these cases with a controller which adjusts it's output at every new blo…
Architecture Enabling Adaptation of Data Integration Processes for a Research Information System
2018
Abstract Today, many efforts have been made to implement information systems for supporting research evaluation activities. To produce a good framework for research evaluation, the selection of appropriate measures is important. Quality aspects of the systems’ implementation should also not be overlooked. Incomplete or faulty data should not be used and metric computation formulas should be discussed and valid. Correctly integrated data from different information sources provide a complete picture of the scientific activity of an institution. Knowledge from the data integration field can be adapted in research information management. In this paper, we propose a research information system f…
New metric products, movies, and 3D models from old stereopairs and their application to the in situ palaeontological site of Ambrona
2020
3D modelling tools from photographic pictures have experienced significant improvements in the last years. One of the most outstanding changes is the spread of the photogrammetric systems based on algorithms referred to as Structure from Motion (SfM) in contrast with the traditional stereoscopic pairs. Nevertheless, the availability of important collections of stereoscopic registers collected during past decades invites us to explore the possibilities for re-using these photographs in order to generate new multimedia products, especially due to the fact that many of the documented elements have been largely altered or even disappeared. This article analyses an example of application to the …
Robustly correlated key‐medical image for DNA‐chaos based encryption
2021
Abstract Medical images include confidential and sensitive information about patients. Hence, ensuring the security of these images is a crucial requirement. This paper proposes an efficient and secure medical image encryption‐decryption scheme based on deoxyribonucleic acid (DNA), one‐dimensional chaotic maps (tent and logistic maps), and hash functions (SHA‐256 and MD5). The first part of the proposed scheme is the key generation based on the hash functions of the image and its metadata. The key then is highly related and intensely sensitive to the original image. The second part is the rotation and permutation of the first two MSB bit‐plans of the medical image to reduce its black backgr…
AI-enabled adaptive learning systems: A systematic mapping of the literature
2021
Abstract Mobile internet, cloud computing, big data technologies, and significant breakthroughs in Artificial Intelligence (AI) have all transformed education. In recent years, there has been an emergence of more advanced AI-enabled learning systems, which are gaining traction due to their ability to deliver learning content and adapt to the individual needs of students. Yet, even though these contemporary learning systems are useful educational platforms that meet students’ needs, there is still a low number of implemented systems designed to address the concerns and problems faced by many students. Based on this perspective, a systematic mapping of the literature on AI-enabled adaptive le…
New client puzzle approach for DoS resistance in ad hoc Networks
2010
In this paper we propose a new client puzzle approach to prevent Denial of Service (DoS) attacks in ad hoc networks. Each node in the network first solves a computational problem and with the solution has to create and solve a client puzzle. By combining computational problems with puzzles, we improve the efficiency and latency of the communicating nodes and resistance in DoS attacks. Experimental results show the effectiveness of our approach.
Editorial for Special Issue “Fine Art Pattern Extraction and Recognition”
2021
Cultural heritage, especially the fine arts, plays an invaluable role in the cultural, historical, and economic growth of our societies [...]
Agreements regarding the property relations of transnational couples and their effects under the application of the twin regulations
2021
It is a true and verifiable fact that the family institution has evolved over recent decades in Europe and throughout the world, but not uniformly or at the same time. This is because it is influenced by social and cultural connotations specific to each State. All of which are respected under EU Regulations 2016/1103 and 2016/1104. This work analyses the Twins Regulations, that gives the couples the possibility of choosing the jurisdiction (art. 7) and applicable legal system underpinning the property consequences of the marriage and registered partnerships (art. 22.1). However, we try to show you these rules absolute freedom of choice is not granted to the parties, because this freedom is …