5 research outputs found
Testing for covarience stationarity in the FTSE all index
No full textSummary. The paper investigates the proposition that the UK FTSE All-share index returns, during the period from January 2nd, 1970, to October 17th, 1997, are covariance stationary. The null hypothesis of variance constancy is rejected by using the Loretan and Phillips test statistic. An intervention model in the spirit of Box and Tiao is used to filter the effects of the 1973 oil crisis and the 1987 market crash on the variance of the returns. We then apply the Loretan and Phillips test statistic to the residuals from the intervention model. The results suggest that the null hypothesis of constant variance is not rejected, indicating that the initial rejection of the null hypothesis for the original data was due to the oil crisis and market crash. This implies that financial times series can be assumed covariance stationary if properly filtered of the effects of known periods of trouble.</p
Proof of Collaborative Contribution — A consensus protocol that incentivizes contribution with applications to distributed solar energy generation
No full textProof of Collaborative Contribution — A consensus protocol that incentivizes contribution with applications to distributed solar energy generatio
SIM-P - A Simplified Consensus Protocol Simulator: Applications to Proof of Reputation-X and Proof of Contribution
No full textBlockchain is a distributed ledger in which participating users with varying levels of trust agree on the ledger's content using a consensus mechanism called consensus protocols. There has been a rising interest in the design of consensus protocols since they play a central role in blockchain architecture. However, many recently proposed consensus protocols lack experimental verification which hampers the possible deployment of these protocols in real-world blockchain networks. In this article, we propose a simple tool called simplified consensus protocol simulator (SIM-P) that can accurately simulate the behavior of these consensus protocols with ease. It is an agent-based stochastic simulator that relies on the sequential Monte Carlo method to model how block publishers are selected. The likelihood of each node (represented as agents) being selected as a block publisher is represented by independent trials in a binomial experiment. We provide a base SIM-P model that simulates Proof of Work (PoW) for benchmarking purposes. The PoW model also serves as the basic structure of the simulator that can be adapted to other protocols. We showcase the flexibility of SIM-P by proposing two additional simulation models for Proof of Reputation-X and Proof of Contribution, both of which lack experimental verification in their original design specifications. We show how the simulator can be used to produce vital metrics, such as throughput, resistance against the 51% attack, and energy consumption. We verify the accuracy of SIM-P by comparing PoW's simulated results with theoretical estimates and historical Bitcoin data
A New Hash Function Based on Chaotic Maps and Deterministic Finite State Automata
No full textIn this paper, a new chaos-based hash function is proposed based on a recently proposed structure known as the deterministic chaotic finite state automata (DCFSA). Out of its various configurations, we select the forward and parameter permutation variant, due to its desirable chaotic properties. These properties are analogous to hash function requirements such as diffusion, confusion and collision resistance. The proposed hash function consists of six machine states and three simple chaotic maps. This particular structure of DCFSA can process larger message blocks (leading to higher hashing rates) and optimizes its randomness. The proposed hash function is analyzed in terms of various security aspects and compared with other recently proposed chaos-based hash functions to demonstrate its efficiency and reliability. Results indicate that the proposed hash function has desirable statistical characteristics, elevated randomness, optimal diffusion and confusion properties as well as flexibility
Cultural heritage discourses and Europeanisation : discursive embedding of cultural herigate in Europe of the regions
No full textIn dit onderzoek wordt erfgoed gezien als objecten waar een zekere betekenis aan wordt toegekend. Die betekenissen staan hier centraal en niet de objecten zelf. Sommige objecten krijgen die Europese relevantie, omdat ze vaak als Europees erfgoed worden bestempeld, voor andere objecten is dat bijvoorbeeld minder duidelijk en hebben de betekenis van nationaal of regionaal erfgoed. Dit proces van betekenisgeving staat centraal in dit proefschrift. Een drietal INTERREG projecten is geselecteerd als case studies (uit Litouwen, Griekenland en Nederland
