Aalto University

About: Aalto University is a education organization based out in Espoo, Finland. It is known for research contribution in the topics: Computer science & Context (language use). The organization has 9969 authors who have published 32648 publications receiving 829626 citations. The organization is also known as: TKK & Aalto-korkeakoulu.

Fifty Years of Artificial Reverberation

Abstract: The first artificial reverberation algorithms were proposed in the early 1960s, and new, improved algorithms are published regularly. These algorithms have been widely used in music production since the 1970s, and now find applications in new fields, such as game audio. This overview article provides a unified review of the various approaches to digital artificial reverberation. The three main categories have been delay networks, convolution-based algorithms, and physical room models. Delay-network and convolution techniques have been competing in popularity in the music technology field, and are often employed to produce a desired perceptual or artistic effect. In applications including virtual reality, predictive acoustic modeling, and computer-aided design of acoustic spaces, accuracy is desired, and physical models have been mainly used, although, due to their computational complexity, they are currently mainly used for simplified geometries or to generate reverberation impulse responses for use with a convolution method. With the increase of computing power, all these approaches will be available in real time. A recent trend in audio technology is the emulation of analog artificial reverberation units, such as spring reverberators, using signal processing algorithms. As a case study we present an improved parametric model for a spring reverberation unit.

The Dynamic Pivot Mechanism

Abstract: We consider truthful implementation of the socially e¢ cient allocation in an independent private-value environment in which agents receive private information over time. We propose a suitable generalization of the pivot mechanism, based on the marginal contribution of each agent. In the dynamic pivot mechanism, the ex-post incentive and ex-post participation constraints are satis…ed for all agents after all histories. In an environment with diverse preferences it is the unique mechanism satisfying ex-post incentive, ex-post participation and e¢ cient exit conditions. We develop the dynamic pivot mechanism in detail for a repeated auction of a single object in which each bidder learns over time her true valuation of the object. We show that the dynamic pivot mechanism is equivalent to a modi…ed second price auction.

Healable, Stable and Stiff Hydrogels: Combining Conflicting Properties Using Dynamic and Selective Three-Component Recognition with Reinforcing Cellulose Nanorods

Abstract: Nanocomposite hydrogels are prepared combining polymer brush-modified ‘hard’ cellulose nanocrystals (CNC) and ‘soft’ polymeric domains, and bound together by cucurbit[8]uril (CB[8]) supramolecular crosslinks, which allow dynamic host–guest interactions as well as selective and simultaneous binding of two guests, i.e., methyl viologen (the first guest) and naphthyl units (the second guest). CNCs are mechanically strong colloidal rods with nanometer-scale lateral dimensions, which are functionalized by surface-initiated atom transfer radical polymerization to yield a dense set of methacrylate polymer brushes bearing naphthyl units. They can then be non-covalently cross-linked through simple addition of poly(vinyl alcohol) polymers containing pendant viologen units as well as CB[8]s in aqueous media. The resulting supramolecular nanocomposite hydrogels combine three important criteria: high storage modulus (G′ > 10 kPa), rapid sol–gel transition (<6 s), and rapid self-healing even upon aging for several months, as driven by balanced colloidal reinforcement as well as the selectivity and dynamics of the CB[8] three-component supramolecular interactions. Such a new combination of properties for stiff and self-healing hydrogel materials suggests new approaches for advanced dynamic materials from renewable sources.