Classification of Hungarian medieval silver coins using x-ray fluorescent spectroscopy and multivariate data analysis

A set of silver coins from the collection of Déri Museum Debrecen (Hungary) was examined by X-ray fluorescent elemental analysis with the aim to assign the coins to different groups with the best possible precision based on the acquired chemical information and to build models, which arrange the coins according to their historical periods. Results: Principal component analysis, linear discriminant analysis, partial least squares discriminant analysis, classification and regression trees and multivariate curve resolution with alternating least squares were applied to reveal dominant pattern in the data and classify the coins into several groups. We also identified those chemical components, which are present in small percentages, but are useful for the classification of the coins. With the coins divided into two groups according to adequate historical periods, we have obtained a correct classification (76-78%) based on the chemical compositions. Conclusions: X-ray fluorescent elemental analysis together with multivariate data analysis methods is suitable to group medieval coins according to historical periods. Keywords: X-ray fluorescence spectroscopy, Multivariate techniques, Coin, Silver, Middle age

Coins of the Eastern Gangas ruler Anantavarman Chodaganga

Attributing the coins of the Eastern Gangas is a difficult task because the coins do not name the ruler, but only are dated in what are thought to be regnal years. Many authors in the past have tended to attribute the coins to the most prominent king of the dynasty, Anantavarman Chodaganga (1078-1147) (hereafter AC), but without any real justification. 2 In a recent paper, I proposed a method of attribution, based on the regnal lengths of the different kings, which would assign a sizable group of the known coins to the last four kings of the dynasty. 3 Coins attributable on a sound basis to AC remained unknown

U.S. coins: forecasting change

Our next article talks about change-as in coins. Every year, the government produces about 70 new coins for every man, woman, and child. But the economy's need for coins can vary from year to year. So how do the U.S. Mint, which makes the coins, and the Federal Reserve, which distributes them, decide how many coins the economy needs? In "U.S. Coins: Forecasting Change," Dean Croushore highlights some facts about coins and describes how demand for change is forecast.Coinage

Quantum Walks with Entangled Coins

We present a mathematical formalism for the description of unrestricted quantum walks with entangled coins and one walker. The numerical behaviour of such walks is examined when using a Bell state as the initial coin state, two different coin operators, two different shift operators, and one walker. We compare and contrast the performance of these quantum walks with that of a classical random walk consisting of one walker and two maximally correlated coins as well as quantum walks with coins sharing different degrees of entanglement. We illustrate that the behaviour of our walk with entangled coins can be very different in comparison to the usual quantum walk with a single coin. We also demonstrate that simply by changing the shift operator, we can generate widely different distributions. We also compare the behaviour of quantum walks with maximally entangled coins with that of quantum walks with non-entangled coins. Finally, we show that the use of different shift operators on 2 and 3 qubit coins leads to different position probability distributions in 1 and 2 dimensional graphs.Comment: Two new sections and several changes from referees' comments. 12 pages and 12 (colour) figure

Coin migration within the euro area

This paper analyses how many euro coins outflow from Germany and which composition of coins is to be expected in the long run. To this end, a simple mathematical model is formulated and calibrated for €1 coins. The introduction of the euro coins in 2002 presented a unique opportunity to analyse the cross-border migration and the mixing process of coins in different euro-area countries. Based on research by Stoyan and depending on growth assumptions, the annual outflow of German €1 coins is calculated to lie somewhere between 4% and 5%. In the long run, the ratio of German €1 coins in Germany is likely to converge to around 50%. --Euro coins,coin volumes,mixing process

A survey of the material and intellectual consequences of trading in undocumented ancient coins : a case study on the North American trade

Ancient coins are among the most widely collected and demanded objects among American collectors of antiquities. A vocal lobby of ancient coin dealers/collectors has arisen to protect the importation of undocumented material into the United States and also seeks to make a distinction between antiquities trafficking and that in ancient coins. Coins are an equally important historical source and are no less important 'antiquities' than a Greek painted vase. I examine the scale of the trade in ancient coins in North America and address some points made by proponents of a continued unfettered ancient coin trade

Quantum Coins

One of the earliest cryptographic applications of quantum information was to create quantum digital cash that could not be counterfeited. In this paper, we describe a new type of quantum money: quantum coins, where all coins of the same denomination are represented by identical quantum states. We state desirable security properties such as anonymity and unforgeability and propose two candidate quantum coin schemes: one using black box operations, and another using blind quantum computation.Comment: 12 pages, 4 figure