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  • 1.
    Andhäll, David
    et al.
    Örebro University, Örebro University School of Business.
    Thörn, Patrik
    Örebro University, Örebro University School of Business.
    Två sidor av samma mynt: Brand alliance bidrar till brand confusion i bankbranschen2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Bergslagens Sparbank as well as other independent(fristående) sparbanker have discoveredthat some of their customers can not separate them from Swedbank. Some customers maythus believe that they are the same bank. This study seeks factors that may contribute to thisproblem, and measures that can counteract. We refer to this problem as brand confusion andmainly have our focus on factors derived from brand alliance, but also from the companyitself and the banking industry. We use a qualitative method where we collect empirical datafrom interviews with four sparbanker. Strategic differences between them, allow us to seehow different factors can contribute to and or counteract brand confusion. This study showsthat the graphic profile, that includes the common symbol and colors, may have great impactwhen it comes to sparbankerna. However, the messy business history that includes thecomplex partner relationship could also have a great impact. Finally, we would also like tomention the importance of how all involving parties in a brand alliance communicates this. Ifit does not come through loud and clear to the customer that there is a partnership, strongsimilarities and ambiguities may affect customers to believe two companies are one and underthe same brand.

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  • 2.
    Arestav, Patrik
    et al.
    University of Gävle, Faculty of Education and Business Studies, Department of Business and Economic Studies, Business administration.
    Sjöstedt, Mikael
    University of Gävle, Faculty of Education and Business Studies, Department of Business and Economic Studies, Business administration.
    Vad avgör kvaliteten på hållbarhetsredovisningen?: Faktorer bakom beslut att tillämpa GRI:s standarder samt upplåta hållbarhetsredovisning för extern granskning2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syfte: Mycket av innehållet i hållbarhetsrapporter kan ses som marknadsföring från företagen som skriver om vilka ambitioner de har för sitt hållbarhetsarbete, men mindre om deras faktiska miljömässiga påverkan. Vi har därför försökt definiera en hållbarhetsrapports kvalitet och sedan studerat vilka faktorer som ligger bakom denna. Faktorer vi intresserat för oss är branschtillhörighet och styrelsesammansättning i form av andel kvinnor i styrelsen. 

    Studiens syfte: Vi ämnar studera vilka faktorer som påverkar kvaliteten i svenska företags hållbarhetsredovisningar. 

    Metod: Studien är utformad efter kvantitativ forskningsmetodik. Urvalet består av svenska börsnoterade företag. För att utröna om samband finns mellan kvaliteten på hållbarhetsrapporterna och våra valda faktorer har studien använt sig av binära logistiska regressionsmodeller. Data har samlats in via databasen Retriever samt genom företagens hållbarhetsrapporter och årsredovisningar. 

    Resultat & slutsats: Studien visar negativa samband mellan kvalité på hållbarhetsrapporter och branschtillhörighet i branscherna sjukvård och industri. Studiens resultat går delvis emot tidigare forskning då den inte finner signifikant positivt samband mellan branschtillhörighet i bransch med hög social och miljömässig påverkan och kvalité på hållbarhetsredovisning. Studien fann inget samband mellan andelelen kvinnor i styrelsen och kvalité på hållbarhetsredovisning. 

    Examensarbetets bidrag: Studien presenterar ett nytt sätt att operationalisera begreppet kvalitet på hållbarhetsredovisningar.

    Förslag till fortsatt forskning: Resultatet visade att en låg andel företag lät sina rapporter bli granskade, vilket för att fortsatt forskning som vill studera variansen inom denna variabel bör innehålla ett större urval. 

    Nyckelord: Hållbarhetsredovisning, GRI, extern granskning, branschtillhörighet, styrelsesammansättning 

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    Vad avgör kvaliteten på hållbarhetsredovisning
  • 3.
    Ovacikli, Aziz Kubilay
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering. Rubico Vibration Analysis AB.
    Pääjärvi, Patrik
    Leblanc, James
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Skewness as an objective function for vibration analysis of rolling element bearings2014In: 2013 8th International Symposium on Image and Signal Processing and Analysis (ISPA 2013: Trieste, Italy, 4-6 Sept. 2013, Piscataway, NJ: IEEE Communications Society, 2014, p. 462-466Conference paper (Refereed)
    Abstract [en]

    The scale invariant third order moment, skewness, is analysed as an objective function to an adaptive gradient ascent algorithm. The purpose is to achieve a spectrum at the filter output that can enable identification of possible bearing defect signatures which are impulsive and periodic. Harmonically related sinusoids are used to represent such signatures and to build a signal model allowing characterization of the objective surface of skewness, providing insight to its convergent behaviour. The results are supported with an experiment from an industry setting. Robustness of the proposed algorithm is demonstrated by examining the frequency spectrum resulting from the signal model.

  • 4.
    Ovacikli, Kubilay
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Carlson, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Pääjärvi, Patrik
    Rubico Vibration Analysis AB.
    Blind pulse compression through skewness maximization on overlapping echoes from thin layers2016In: IEEE Ultrasonics Symposium 2016, Tours France, September 18-21, 2016, Piscataway, NJ: IEEE conference proceedings, 2016, article id 7728571Conference paper (Refereed)
    Abstract [en]

    Pulse compression on overlapping echoes without knowledge of the pulse shape, transducer and propagation path impulse response is examined to provide valuable information about the sample structure in ultrasonic testing. A comparison against previous research is presented on two different levels of overlap severity with simulated signals. By exploiting the knowledge on the statistical characteristics of the signal of interest, an appropriate measure of merit, such as skewness, is maximized to promote impulsive occurrences to both extract the excitation signal and to enhance the impulse response of a material under test.

  • 5.
    Ovacikli, Kubilay
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering. Rubico Vibration Analysis AB.
    Pääjärvi, Patrik
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Leblanc, James
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Carlson, Johan E.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Uncovering harmonic content via skewness maximization: a Fourier analysis2014In: Proceedings of the 22nd European Signal Processing Conference (EUSIPCO 2014): Lisbon, Portugal, 1-5 Sept. 2014, Piscataway, NJ: IEEE Communications Society, 2014, p. 481-485, article id 6952135Conference paper (Refereed)
    Abstract [en]

    Blind adaptation with appropriate objective function results in enhancement of signal of interest. Skewness is chosen as a measure of impulsiveness for blind adaptation to enhance impacting sources arising from defective rolling bearings. Such impacting sources can be modelled with harmonically related sinusoids which leads to discovery of harmonic content with unknown fundamental frequency by skewness maximization. Interfering components that do not possess harmonic relation are simultaneously suppressed with proposed method. An experimental example on rolling bearing fault detection is given to illustrate the ability of skewness maximization in uncovering harmonic content.

  • 6. Pääjärvi, Patrik
    Adaptive blind deconvolution using third-order moments: exploiting asymmetry2005Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis focuses on the use of third-order statistics in adaptive blind deconvolution of asymmetric impulsive signals. Traditional methods are typically based on fourthorder moments, which can discriminate signals with heavy-tailed probability functions (i.e. `spiky' signals) from corresponding filtered versions. The work herein demonstrates that, by using third-order central moments, asymmetry in such signals (e.g. only positive `spikes') can be exploited to achieve faster convergence of algorithms and increased robustness to noise. The reasons for these benefits lie mainly in the use of error functions with lower polynomial orders, which leads to simpler gradient equations, improving the convergence rate. The increased robustness to noise is due to the fact that all odd-order statistics of symmetric signals (e.g. Gaussian noise) are zero. A previously known computationally simple, norm-constrained algorithm for gradient search is also examined. It is demonstrated that this algorithm accomplishes third-order moment maximization by gradient ascent, without the undesired e ect of increasing filter norm. Norm-constrained optimization is commonly achieved using periodic normalization of the filter vector, involving costly divides and square-root operations. The investigated algorithm requires significantly fewer operations, and uses only multiplications and additions, making it well suited for implementation on fixed-point digital signal processors. Numerical experiments, demonstrating the usefulness of the proposed methods, include blind deconvolution of sound from a diesel engine, and blind equalization of a synthetic ultra-wideband (UWB) communication channel.

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  • 7.
    Pääjärvi, Patrik
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Blind equalization using third-order moments2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The use of third-order moments in blind linear equalization has been studied with emphasis on their performance in on-line methods of low complexity. Blind equalization has widespread use in areas such as digital communications, acoustics, geophysical exploration, image processing and general measurement problems. The objective is to recover a desired, unknown source signal from distorted observations using a linear filter. In contrast to classical methods of deconvolution or trained equalization, no model of the distorting system or temporal observations of the source are assumed. Instead, knowledge of the higher-order source statistics are exploited to find an appropriate equalizer setting through some iterative numerical procedure. The application field and research area have traditionally focused on methods based on fourth-order statistics. Examples are various kurtosis-maximization approaches and the widely used constant modulus algorithm (CMA). While qualifying for blind methods, third-order statistics have attracted less attention, mainly due to the reason that they can only be used when the source signal is asymmetric, i.e.\ when the probability density is skewed. As a consequence of the more restricted usability of third-order methods, mostly experimental research results can be found, with little explanation for their performance. This work provides analytic and numerical results motivating why third-order methods should generally be chosen over their fourth-order counterparts when possible. It is shown that they possess improved convergence properties and robustness to noise, and that they lend themselves to efficient implementation on digital real-time hardware. These combined features make third-order methods an interesting option for on-line blind equalization.

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  • 8. Pääjärvi, Patrik
    et al.
    Leblanc, James
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Blind equalization of PPM signals using third-order moments2007In: 2007 IEEE 8th Workshop on Signal Processing Advances in Wireless Communications: SPAWC 2007, Helsinki, Finland, 17 - 20 June 2007, Piscataway, NJ: IEEE Communications Society, 2007Conference paper (Refereed)
    Abstract [en]

    In pulse-position modulation (PPM) signaling, the time location of short-duration pulses are used to convey information over a communication channel. For successful noncoherent reception, the channel duration must be short compared to the symbol interval. This paper analyzes the use of third moments in a blind adaptive equalizer setting to limit the effective delay spread of the channel. Results detail the global convergence properties of the proposed method, showing that the parameters approach ISI-free settings under general conditions.

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  • 9. Pääjärvi, Patrik
    et al.
    Leblanc, James
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Blind linear equalization of PPM signals using third-order moments2010In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 9, no 4, p. 1298-1302Article in journal (Refereed)
    Abstract [en]

    A novel blind equalization strategy for pulse position modulation (PPM) based on maximizing the third-order moment of the equalizer output is presented. Compared to traditional fourth-order (e.g. kurtosis-based) methods, third-order moments give faster convergence and are less sensitive to noise. This work demonstrates that the intersymbol interference that plagues typical indoor ultra wideband (UWB) channels can be combatted using a third-moment maximizing blind equalizer which could therefore provide a cold start-up for a decision-directed scheme. Adaptation is shown to be asymptotically globally convergent with increasing time-hopped PPM frame length. Simulation experiments compare the performance to standard fourth-order schemes in practical settings, taking into account the conditions of time-hopping,multiple-access interference and a realistic UWB channel model.

  • 10. Pääjärvi, Patrik
    et al.
    Leblanc, James
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Computationally efficient norm-constrained adaptive blind deconvolution using third-order moments2006In: 2006 IEEE International Conference on Acoustics, Speed [i.e. Speech] and Signal Processing: Toulouse, France, 14 - 19 May 2006, Piscataway, NJ: IEEE Communications Society, 2006, Vol. 3, p. 752-755Conference paper (Refereed)
    Abstract [en]

    Third-order central moments have been shown to be well suited as objective functions for blind deconvolution of impulsive signals. Online implementations of such algorithms may suffer from increasing filter norm, forcing adaptation under constrained filter norm. This paper extends a previously known efficient algorithm with self-stabilizing properties to the case of using a third-order moment objective function. New results herein use averaging analysis to determine adaptation stepsize conditions for asymptotic stability of the filter norm.

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  • 11. Pääjärvi, Patrik
    et al.
    Leblanc, James
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Skewness maximization for impulsive sources in blind deconvolution2004In: Norsig 2004: proceedings of the 6th Nordic Signal Processing Symposium : June 9-11, 2004, Espoo, Finland / [ed] Jarmo M.A. Tanskanen, Helsinki: Helsinki University of Technology , 2004, p. 304-307Conference paper (Refereed)
    Abstract [en]

    In blind deconvolution problems, a deconvolution filter is often determined in an iterative manner, where the filter taps are adjusted to maximize some objective function of the filter output signal. The kurtosis of the filter output is a popular choice of objective function. In this paper, we investigate some advantages of using skewness, instead of kurtosis, in situations where the source signal is impulsive, i.e. has a sparse and asymmetric distribution. The comparison is based on the error surface characteristics of skewness and kurtosis.

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    fulltext
  • 12.
    Pääjärvi, Patrik
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Leblanc, James P.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Online adaptive blind deconvolution based on third-order moments2005In: IEEE Signal Processing Letters, ISSN 1070-9908, E-ISSN 1558-2361, Vol. 12, no 12, p. 863-866Article in journal (Refereed)
    Abstract [en]

    Traditional methods for online adaptive blind deconvolution using higher order statistics are often based on even-order moments, due to the fact that the systems considered commonly feature symmetric source signals (i.e., signals having a symmetric probability density function). However, asymmetric source signals facilitate blind deconvolution based on odd-order moments. In this letter, we show that third-order moments give the benefits of faster convergence of algorithms and increased robustness to additive Gaussian noise. The convergence rates for two algorithms based on third- and fourth-order moments, respectively, are compared for a simulated ultra-wideband communication channel.

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    FULLTEXT01
1 - 12 of 12
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