3,615 research outputs found

    Inversion of acoustical data from the SW06 experiment, using a statistical method for signal characterization

    Get PDF
    his paper presents an application of an acoustic signal characterization scheme for ocean acoustic tomography and geoacoustic inversions proposed by Taroudakis et al., using real data. The work is the first attempt to validate the proposed scheme with data taken from sea experiments. The data have been collected during the SW06 experiment held in the New Jersey Continental Shelf and the inversion results (sea-bed geoacoustic parameters and source range) are compared with those reported by Bonnel and Chapman. The comparison and the signal reconstruction using estimated values of the model parameters is satisfactory being an indication that the new signal characterization method can be used in practical applications of acoustical oceanography

    Nonlinear time-warping made simple: a step-by-step tutorial on underwater acoustic modal separation with a single hydrophone

    Get PDF
    © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Bonnel, J., Thode, A., Wright, D., & Chapman, R. Nonlinear time-warping made simple: a step-by-step tutorial on underwater acoustic modal separation with a single hydrophone. The Journal of the Acoustical Society of America, 147(3), (2020): 1897, doi:10.1121/10.0000937.Classical ocean acoustic experiments involve the use of synchronized arrays of sensors. However, the need to cover large areas and/or the use of small robotic platforms has evoked interest in single-hydrophone processing methods for localizing a source or characterizing the propagation environment. One such processing method is “warping,” a non-linear, physics-based signal processing tool dedicated to decomposing multipath features of low-frequency transient signals (frequency f  1 km). Since its introduction to the underwater acoustics community in 2010, warping has been adopted in the ocean acoustics literature, mostly as a pre-processing method for single receiver geoacoustic inversion. Warping also has potential applications in other specialties, including bioacoustics; however, the technique can be daunting to many potential users unfamiliar with its intricacies. Consequently, this tutorial article covers basic warping theory, presents simulation examples, and provides practical experimental strategies. Accompanying supplementary material provides matlab code and simulated and experimental datasets for easy implementation of warping on both impulsive and frequency-modulated signals from both biotic and man-made sources. This combined material should provide interested readers with user-friendly resources for implementing warping methods into their own research.This work was supported by the Office of Naval Research (Task Force Ocean, project N00014-19-1-2627) and by the North Pacific Research Board (project 1810). Original warping developments were supported by the French Delegation Generale de l'Armement

    Trans-dimensional inversion of modal dispersion data on the New England Mud Patch

    Get PDF
    © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Bonnel, J., Dosso, S. E., Eleftherakis, D., & Chapman, N. R. Trans-dimensional inversion of modal dispersion data on the New England Mud Patch. IEEE Journal of Oceanic Engineering, 45(1), (2020): 116-130, doi:10.1109/JOE.2019.2896389.This paper presents single receiver geoacoustic inversion of two independent data sets recorded during the 2017 seabed characterization experiment on the New England Mud Patch. In the experimental area, the water depth is around 70 m, and the seabed is characterized by an upper layer of fine grained sediments with clay (i.e., mud). The first data set considered in this paper is a combustive sound source signal, and the second is a chirp emitted by a J15 source. These two data sets provide differing information on the geoacoustic properties of the seabed, as a result of their differing frequency content, and the dispersion properties of the environment. For both data sets, source/receiver range is about 7 km, and modal time-frequency dispersion curves are estimated using warping. Estimated dispersion curves are then used as input data for a Bayesian trans-dimensional inversion algorithm. Subbottom layering and geoacoustic parameters (sound speed and density) are thus inferred from the data. This paper highlights important properties of the mud, consistent with independent in situ measurements. It also demonstrates how information content differs for two data sets collected on reciprocal tracks, but with different acoustic sources and modal content.10.13039/100000006-Office of Naval Research 10.13039/100007297-Office of Naval Research Globa

    Strategy and continuous improvement in small-to-medium Australian manufacturers

    Full text link
    While Australian firms have generally recognised the value of continuous improvement (CI) in improving performance, many have yet to develop systems to ensure that the efforts of the CI program are focussed on issues of strategic importance to the company. In fact, as recognised in operations management generally, CI activities can have a significant impact on the development of strategy as well as its implementation. The research reported here uses a CI mapping methodology to chart the relationship between CI and strategy in small- to medium-sized manufacturers. Analysis of the link between the firms’ strategies and CI programs indicates that most firms involved in the study made little attempt to link the two and some appear to be unaware of any need to do so. However, such findings seem to be dependent on company size, the maturity of the CI program and the competitive position of the firm. The paper also includes an examination of the role of operations and shopfloor CI in company strategy, particularly as related to SMEs

    Organisational and national culture : a study of overlap and interaction in the Literature

    Full text link
    Terms such as Globalisation and cross-cultural management are widely used by both organisational managers and academics. While it is the intention of academics and industry analysts to explain the phenomena and discover principles to guide the practitioners, human resource managers are dealing with the workplace changes implicit in these terms on an increasingly frequent basis. These managers are facing increasingly diverse workforces, and must cope with all the challenges and opportunities inherent in such diversity. This article presents a new approach to examining the key literature on organisational and national culture in three main areas. Firstly, areas of convergence between various theories on culture are identified. Secondly, the article illustrates and discusses where these theories diverge from each other. Thirdly, drawing on the principles discussed in the article, a framework of national culture is developed from existing literature that highlights the convergence found in existing models

    A learning laboratory approach for business improvement : the case of discontinuous innovation

    Full text link
    This paper considers the current situation within Australian manufacturing SMEs and their approaches to innovation and international competitive advantage. Using the viewpoint and language of complexity theory, we consider the variety of possibilities available to SMEs in this area. We then consider a particular international project on Discontinuous Innovation, how this has been deployed in Europe and Australia and the knowledge gained from our interactions with Australian SMEs to date around this project. Finally we consider the general development of a &ldquo;Learning Laboratory&rdquo; approach to working with SMEs and the differences required to make such approach successful in Europe and in different settings in Australia.<br /

    TQM and labour productivity in Jordanian industrial companies

    Full text link
    Reports on research to determine the degree of application of total quality management (TQM) philosophy and practices in industrial corporations in Jordan. Uses primary and secondary empirical data to examine the link between TQM and labour productivity. Survey responses were classified into two groups: high-TQM implementation and low-TQM implementation. Found that mean labour productivity measurements for high-TQM companies were significantly higher than for low-TQM companies over the period 1993-1998. Also, mean growth rates of labour productivity measurements for companies with high-level TQM were higher than for those with low-level TQM during this period. Regression analysis demonstrated a statistically significant positive relationship between TQM and labour productivity

    The interface between intrapreneurship, innovation and IT governance

    Full text link
    The purpose of this conceptual paper is to examine the links, as reported in the international literature, between intrapreneurship, innovativeness and IT governance within medium to large organizations. A cross disciplinary literature review was conducted and yielded a theoretical framework for identifying and understanding the critical elements underpinning and driving innovation and intrapreneurship performance and their relationship with key aspects of IT governance within organizations.<br /

    Pervasive limitations : innovating with ambient intelligence (AmI) technologies and restricted absorptive capacity in Australian SME manufacturers

    Full text link
    The last 25 years have seen rapid increases in the number and sophistication of technological and process innovations in large manufacturers, producing dramatic improvements in productivity and efficiency. However, smaller manufacturers&rsquo; adoption of such innovations has been uneven. Ambient Intelligence (AmI) technologies are being positioned as the next performance and productivity enhancing purchase for manufacturers. This paper defines and gives examples of AmI technologies in current use, summarises AmI technologies of potential interest to small and medium enterprise (SME) manufacturers, and identifies potential impacts of restricted absorptive capacity in SMEs on the adoption of AmI technologies. Comparing two SME manufacturers, one from Germany and one from Australia illustrates a potential application of generic AmI technology based business solutions to a range of SME manufacturers.<br /
    corecore