The MAC function Pelican 2.0

We present an update of the Pelican MAC function, called Pelican 2.0. Both versions have the Alred construction and are based on Rijndael. they are a factor 2.5 more efficient than CBC-MAC with Rijndael, while providing a comparable claimed security level. The difference between Pelican 2.0 and the original version is that the initial value changes from the all-zero string to another constant. The reason for this is the negative impact on security if key check values are available computed with a certain standard key check value algorithm that applies the block cipher to the zero string and takes as key check value its truncated output. The security impact of this on a number of standard MACs is studied in Cryptology ePrint Archive Report 2014/183 and the analysis carries over for Pelican

Wave-Slope Soaring of the Brown Pelican

We theoretically assess the energy savings associated with wave-slope soaring of the brown pelican over near-shoaling ocean surface waves. The steady, constant altitude flight of a pelican is analyzed as a control. The airflow induced by a passing wave, or the “wave-induced wind,” is theoretically analyzed for shallow water solitary waves. These waves are assumed to be well described by the KdV equation. We use potential flow theory to describe the wave- induced wind. Using a regular expansion of the Stokes stream function and the Green’s function for Laplace in 2D with Dirichlet boundary conditions, we obtain integral expressions for the horizontal and vertical components of the wave-induced wind in a frame of reference moving with the wave. The theory results in expressions wherein provided with the amplitude and period of an incoming swell, horizontal and vertical components of the wave-induced wind in a frame of reference moving with the wave are produced. Wave-slope soaring flight is analyzed over near-shoaling solitary waves on size scales corresponding to wind swell, with amplitude of 1m and period of 10s. We find an upper bound benefit of 57.6% decrease in required mechanical power output as compared with flight out of ground effect and 52.4% benefit as compared with standard ground effect flight. The theory in this work define sufficient evidence that wave- slope soaring could become a viable strategy for energy efficient flight of unmanned autonomous vehicles (UAVs)

An evaluation of emergent macrophytes and use among groups of aquatic taxa

Aquatic vegetation serves an important ecological role. Previous research on the interactions of macrophytes and aquatic organisms has focused primarily on submersed macrophytes due to their structural complexity and associated ecological impacts. However, the role of emergent vegetation is far less understood and often overlooked because they lack structural complexity. We evaluated 3 common emergent macrophytes and an open water habitat, and determined use among multiple aquatic taxa. Pelican Lake, Nebraska, USA, served as our study system because it is dominated by 3 emergent macrophytes: common cattail (Typha latifolia), softstem bulrush (Schoenoplectus tabernaemontani), and common reed (Phragmites australis). Juvenile fishes (yellow perch [Perca flavescens] and bluegill [Lepomis macrochirus]), zooplankton, and benthic macroinvertebrates were sampled concurrently in each habitat patch over 3 months (Aug, Sep, and Oct). We identified few clear or consistent overall patterns in habitat use among emergent vegetation species across these aquatic taxa. However, bluegill and some zooplankton taxa were more abundant in emergent vegetation compared to open water habitats. Conversely, habitat use for some macroinvertebrate taxa differed among emergent vegetation species. Our results suggest that managers could select from a variety of emergent vegetation species to address management objectives, while also balancing ecological and social tradeoffs

On the Security of Keyed Hashing Based on Public Permutations

Doubly-extendable cryptographic keyed functions (deck) generalize the concept of message authentication codes (MAC) and stream ciphers in that they support variable-length strings as input and return variable-length strings as output. A prominent example of building deck functions is Farfalle, which consists of a set of public permutations and rolling functions that are used in its compression and expansion layers. By generalizing the compression layer of Farfalle, we prove its universality in terms of the probability of differentials over the public permutation used in it. As the compression layer of Farfalle is inherently parallel, we compare it to a generalization of a serial compression function inspired by Pelican-MAC. The same public permutation may result in different universalities depending on whether the compression is done in parallel or serial. The parallel construction consistently performs better than the serial one, sometimes by a big factor. We demonstrate this effect using Xoodoo[3], which is a round-reduced variant of the public permutation used in the deck function Xoofff

Avian representations from prehistoric and medieval sites on the Maltese Islands

The aim of this publication is to catalogue the avian representations discovered in local prehistoric and medieval sites, to illustrate as many of these as possible and to register a hitherto unrecorded find of a miniature clay bird from Mnajdra (Qrendi, Malta) and of a North African oil lantern with a bird emblema on its disc.peer-reviewe

Small MACs from Small Permutations

The concept of lightweight cryptography has gained in popularity recently, also due to various competitions and standardization efforts specifically targeting more efficient algorithms, which are also easier to implement. One of the important properties of lightweight constructions is the area of a hardware implementation, or in other words, the size of the implementation in a particular environment. Reducing the area usually has multiple advantages like decreased production cost or lower power consumption. In this paper, we focus on MAC functions and on ASIC implementations in hardware, and our goal is to minimize the area requirements in this setting. For this purpose, we design a new MAC scheme based on the well-known Pelican MAC function. However, in an effort to reduce the size of the implementation, we make use of smaller internal permutations. While this certainly leads to a higher internal collision probability, effectively reducing the allowed data, we show that the full security is still maintained with respect to other attacks, in particular forgery and key recovery attacks. This is useful in scenarios which do not require large amounts of data. Our detailed estimates, comparisons, and concrete benchmark results show that our new MAC scheme has the lowest area requirements and offers competitive performance. Indeed, we observe an area advantage of up to 30% in our estimated comparisons, and an advantage of around 13% compared to the closest competitor in a concrete implementation

Out of the wilderness : a fourteenth-century English drawing of John the Baptist

London, British Library, MS Royal 10 B XIV contains a large drawing of St. John the Baptist that is both exceptional for its quality and iconographically unique. Not previously noticed by art historians, it constitutes an important addition to English art of the early to mid-fourteenth century. This paper explores the physical nature of the drawing, its bibliographical context (in a book of natural philosophy), the nature and meaning of its imagery, and its artistic context and associations, within the broader framework of its ownership and use by Benedictine monks of Saint Augustine's Abbey, Canterbury. The drawing is considered a symptom of a wider interest in the acquisition of manuscript illumination at the abbey during the first half of the fourteenth century. It can be dated to about 1335-40 and is thought to have been executed in southeast England or East Anglia, where the works of art to which it is closest in stylistic and iconographic terms were produced. The iconography includes a number of motifs rare or unparalleled in images of John the Baptist, including a figure of Salome beneath the saint's feet and, most remarkably, a monumental Gothic arch composed of living oak trees, which frames the saint. The detail and semantic richness of this imagery make it practically certain that the drawing was made as a focus of devotion, probably for the manuscript's first recorded owner, the Oxford scholar-monk John of Lingfield.Publisher PDFPeer reviewe

Reclaiming Female Relational Space: In Her Own Image by Eavan Bolan

Zadanie pt. „Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki” nr 885/P-DUN/2014 dofinansowane zostało ze środków MNiSW w ramach działalności upowszechniającej nauk