Auralization of Amplitude Modulated Helicopter Flyover Noise

Rotorcraft noise is an active field of study as the sound produced by these vehicles is often found to be annoying. A means to auralize rotorcraft flyover noise is sought to help understand the factors leading to annoyance. Previous work by the authors auralized a complete flyover event in which the source noise synthesis traversed a range of emission angles. The source noise definition process for the synthesis used helicopter flyover recordings. Although this process yielded both periodic and aperiodic (modulation) components at a set of discrete emission angles, only the periodic components were used in the previous work to synthesize the sound of the flyover event. In the current work, aperiodic amplitude modulation is incorporated into the source noise synthesis to improve its fidelity toward assessing rotorcraft noise annoyance. The method is demonstrated using ground recordings from a flight test of the AS350 helicopter for the source noise definition

On the Fate of Protests: Dynamics of Social Activation and Topic Selection Online and in the Streets

This chapter studies individual and network conditions for the emergence of large social protests in an agent-based model. We use two recent examples from Iran and Germany to inform the modeling process. In our agent-based model, people, who are interconnected in networks, interact and exchange their concerns on a finite number of topics. They may start to protest either because of their concern or because the fraction of protesters in their social contacts exceeds their protest threshold. In contrast to many other models of social protest, we also study the coevolution of topics of concern in the not (yet) protesting public. Given that often a small number of citizens starts a protest, its fate depends not only on the dynamics of social activation but also on the buildup of concern with respect to competing topics. Nowadays, this buildup happens decentralized through social media. The model reproduces characteristic patterns of the evolution of the two empirical cases of social protests in Iran and Germany. In particular, our results show that positions of agents with certain concern levels on certain topics within the networks are important for the fate of protests

Optimized sound diffusers based on sonic crystals using a multiobjective evolutionary algorithm

Sonic crystals have been demonstrated to be good candidates to substitute for conventional diffusers in order to overcome the need for extremely thick structures when low frequencies have to be scattered, however, their performance is limited to a narrow band. In this work, multiobjective evolutionary algorithms are used to extend the bandwidth to the whole low frequency range. The results show that diffusion can be significantly increased. Several cost functions are considered in the paper, on the one hand to illustrate the flexibility of the optimization and on the other hand to demonstrate the problems associated with the use of certain cost functions. A study of the robustness of the optimized diffusers is also presented, introducing a parameter that can help to choose among the best candidates. Finally, the advantages of the use of multiobjective optimization in comparison with conventional optimizations are discussed.This work was partially supported by the Spanish "Ministerio de Economia y Competitividad" under the projects TEC2015-68076-R and DPI2015-71443-R.Redondo, J.; Sánchez Pérez, JV.; Blasco, X.; Herrero Durá, JM.; Vorlander, M. (2016). Optimized sound diffusers based on sonic crystals using a multiobjective evolutionary algorithm. Journal of the Acoustical Society of America. 139(5):2807-2814. doi:10.1121/1.4948580S28072814139

openMat - Management of Acoustic Material (Meta-)Properties Using an Open Source Database Format

While most acoustic material properties are standardized today, the way of digitally storing such data is not. Commercial applications, internal developments and open-source solutions usually use their own proprietary file formats that make a data exchange practically impossible. This circumstance led to the foundation of openMat. This cooperative project aims at defining a standard for the storage of both standardized acoustic material properties and supplemental meta-information. In the current conceptual design, openMat supports the following material properties: absorption-, scattering- and diffusion coefficients as well as bidirectional transfer functions and complex impedances. In addition, meta properties are assignable to each material, e.g., multilingual material description, information on pricing and data acquisition, and additional files such as textures and 3D models. Using such meta-information makes the database already applicable during the early and graphical design stage of a room. The project proposes an Extensible Markup Language (XML) database format since XML is human- readable, machine-processable, and a de-facto standard today. However, the openMat project provides not only the database specification, but also a huge example library, plug-ins and an open source, platform- independent database editor with convenient graphical user interface and comprehensive manual. All content is freely available on the project site www.openMat.info

QPRT: a potential marker for follicular thyroid carcinoma including minimal invasive variant; a gene expression, RNA and immunohistochemical study

Background The differential diagnosis between follicular thyroid adenoma and minimal invasive follicular thyroid carcinoma is often difficult for several reasons. One major aspect is the lack of typical cytological criteria in well differentiated specimens. New marker molecules, shown by poly- or monoclonal antibodies proved helpful. Methods We performed global gene expression analysis of 12 follicular thyroid tumours (4 follicular adenomas, 4 minimal invasive follicular carcinomas and 4 widely invasive follicular carcinomas), followed by immunohistochemical staining of 149 cases. The specificity of the antibody was validated by western blot analysis Results In gene expression analysis QPRT was detected as differently expressed between follicular thyroid adenoma and follicular thyroid carcinoma. QPRT protein could be detected by immunohistochemistry in 65% of follicular thyroid carcinomas including minimal invasive variant and only 22% of follicular adenomas. Conclusion Consequently, QPRT is a potential new marker for the immunohistochemical screening of follicular thyroid nodules