Tallinn University of Technology

About: Tallinn University of Technology is a education organization based out in Tallinn, Estonia. It is known for research contribution in the topics: European union & Oil shale. The organization has 3688 authors who have published 10313 publications receiving 145058 citations. The organization is also known as: Tallinn Technical University & Tallinna Tehnikaülikool.

Designing a Smart-Contract Application Layer for Transacting Decentralized Autonomous Organizations

Abstract: This keynote paper addresses existing problems with traditional non-machine readable contracts that are based on trust. Such contracts have mostly a ceremonial purpose between transacting business parties and when conflicts occur, traditional contracts are often not enforcible. On the other hand, so called smart contracts that are machine readable and supported by blockchain-technology transactionalities, do not require qualitative trust between contracting parties as blockchain establish instead a quantitative notion of trust. However, currently existing smart-contract solutions that equip the protocol layer on top of blockchains with Turing-complete programming languages, lead to the false claim by industry practitioners they can manage smart contracts successfully. Instead, it is important to start considering the currently missing application layer for smart contracts.

Two- and three-dimensional computation of solitary wave runup on non-plane beach

Abstract: . Solitary wave runup on a non-plane beach is studied analytically and numerically. For the theoretical approach, nonlinear shallow-water theory is applied to obtain the analytical solution for the simplified bottom geometry, such as an inclined channel whose cross-slope shape is parabolic. It generalizes Carrier-Greenspan approach for long wave runup on the inclined plane beach that is currently used now. For the numerical study, the Reynolds Averaged Navier-Stokes (RANS) system is applied to study soliton runup on an inclined beach and the detailed characteristics of the wave processes (water displacement, velocity field, turbulent kinetic energy, energy dissipation) are analyzed. In this study, it is theoretically and numerically proved that the existence of a parabolic cross-slope channel on the plane beach causes runup intensification, which is often observed in post-tsunami field surveys.

Recursive coalgebras from comonads

Abstract: The concept of recursive coalgebra of a functor was introduced in the 1970s by Osius in his work on categorical set theory to discuss the relationship between wellfounded induction and recursively specified functions. In this paper, we motivate the use of recursive coalgebras as a paradigm of structured recursion in programming semantics, list some basic facts about recursive coalgebras and, centrally, give new conditions for the recursiveness of a coalgebra based on comonads, comonad-coalgebras and distributive laws of functors over comonads. We also present an alternative construction using countable products instead of coffee comonads.

The Reduced Cross-Section Method for Evaluation of the Fire Resistance of Timber Members: Discussion and Determination of the Zero-Strength Layer

Abstract: The reduced cross-section method (RCSM) is included in Eurocode 5 (EN-1995-1-2) for the design of timber members in fire conditions. The method considers the strength and stiffness reduction beneath the charred layer by adding an additional depth (known as the ‘zero-strength’ layer) to the charring depth. The zero-strength layer is one of the key parameters for the fire design of timber members. Recently, some concerns have been raised that the zero-strength layer might be non-conservative in some applications. This paper presents the background to the RCSM, followed by a short discussion on the mechanical assumptions, simplifications and possible limitations of the method itself. Further, it discusses determination of the zero-strength layer thickness for members in bending, tension and compression, and provides guidelines on the use of standard experimental tests to determine this quantity. For demonstration of the determination procedure, the results of fire tests in bending, tension and compression were analysed following the described procedure. Results show that the zero-strength layer exceeds the value used in practice, indicate that the method of Eurocode 5 may be non-conservative and should be revised.