Search results for: Matti Vilkko

Authors: Tomi Roinila, Aki Taskinen, Matti Vilkko

Abstract:

Switched-mode converters play now a significant role in modern society. Their operation are often crucial in various electrical applications affecting the every day life. Therefore, the quality of the converters needs to be reliably verified. Recent studies have shown that the converters can be fully characterized by a set of frequency responses which can be efficiently used to validate the proper operation of the converters. Consequently, several methods have been proposed to measure the frequency responses fast and accurately. Most often correlation-based techniques have been applied. The presented measurement methods are highly sensitive to external errors and system nonlinearities. This fact has been often forgotten and the necessary uncertainty analysis of the measured responses has been neglected. This paper presents a simple approach to analyze the noise and nonlinearities in the frequency-response measurements of switched-mode converters. Coherence analysis is applied to form a confidence interval characterizing the noise and nonlinearities involved in the measurements. The presented method is verified by practical measurements from a high-frequency switchedmode converter.

Keywords: Switched-mode converters, Frequency analysis, CoherenceAnalysis.

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Authors: Tingan Tang, Kimmo Karhu, Matti Hamalainen

Abstract:

Although in sustainable development field, innovative solutions have been sought worldwide by environmental groups, academia, governments and companies for many years, recently, citizens and communities have emerged as a new group and taken more and more active role in this field. Many scholars call for more research on the role of community and community innovation in sustainable development. This paper is to respond to the calls. In this paper, we first summarize a comprehensive set of innovation principles. Then, we do a qualitative cross case study by comparing three community innovation cases in three different areas of sustainable development according to the innovation principles. Finally, we summarize the case comparison and discuss the implications to sustainable development. A unified role model and innovation distribution map of community innovation are developed to better understand community innovation in sustainable development..

Keywords: Community innovation, grassroots innovation, sustainable development, sustainability.

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Authors: Omar D. Mohammed, Matti Rantatalo, Uday Kumar

Abstract:

In this paper an analytical crack propagation scenario is proposed which assumes that a crack propagates in the tooth root in both the crack depth direction and the tooth width direction, and which is more reasonable and realistic for non-uniform load distribution cases than the other presented scenarios. An analytical approach is used for quantifying the loss of time-varying gear mesh stiffness with the presence of crack propagation in the gear tooth root. The proposed crack propagation scenario can be applied for crack propagation modelling and monitoring simulation, but further research is required for comparison and evaluation of all the presented crack propagation scenarios from the condition monitoring point of view.

Keywords: Crack propagation, Gear tooth crack, Time varying gear mesh stiffness.

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Authors: Kalyankumar M. Matti, Chandrashekhar J. Savanurmath, Shivayogeppa B. Hinchigeri

Abstract:

A rare phenomenon of SDS-induced activation of a latent protease activity associated with the purified silkworm excretory red fluorescent protein (SE-RFP) was noticed. SE-RFP aliquots incubated with SDS for different time intervals indicated that the protein undergoes an obligatory breakdown into a number of subunits which exhibit autoproteolytic (acting upon themselves) and/or heteroproteolytic (acting on other proteins) activities. A strong serine protease activity of SE-RFP subunits on Bombyx mori nucleopolyhedrovirus (BmNPV) polyhedral protein was detected by zymography technique. A complete inhibition of BmNPV infection to silkworms was observed by the oral administration assay of the SE-RFP. Here, it is proposed that the SE-RFP prevents the initial infection of BmNPV to silkworms by obliterating the polyhedral protein. This is the first report on a silkworm red fluorescent protein that exhibits a protease activity on exposure to SDS. The present studies would help in understanding the antiviral mechanism of silkworm red fluorescent proteins.

Keywords: BmNPV, polyhedra, SE-RFP, SDS-induced protease activity, zymography.

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Authors: Maria Jokela, Matti Kutila, Jukka Laitinen, Florian Ahlers, Nicolas Hautière, TobiasSchendzielorz

Abstract:

It has been shown that in most accidents the driver is responsible due to being distracted or misjudging the situation. In order to solve such problems research has been dedicated to developing driver assistance systems that are able to monitor the traffic situation around the vehicle. This paper presents methods for recognizing several circumstances on a road. The methods use both the in-vehicle warning systems and the roadside infrastructure. Preliminary evaluation results for fog and ice-on-road detection are presented. The ice detection results are based on data recorded in a test track dedicated to tyre friction testing. The achieved results anticipate that ice detection could work at a performance of 70% detection with the right setup, which is a good foundation for implementation. However, the full benefit of the presented cooperative system is achieved by fusing the outputs of multiple data sources, which is the key point of discussion behind this publication.

Keywords: Smart roads, traffic monitoring, traffic scenedetection.

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