Pre-stimulus beta oscillations within left posterior sylvian regions impact auditory temporal order judgment accuracy.

Both neural and behavioral responses to stimuli are influenced by the state of the brain immediately preceding their presentation, notably by pre-stimulus oscillatory activity. Using frequency analysis of high-density electroencephalogram coupled with source estimations, the present study investigated the role of pre-stimulus oscillatory activity in auditory spatial temporal order judgments (TOJ). Oscillations within the beta range (i.e. 18-23Hz) were significantly stronger before accurate than inaccurate TOJ trials. Distributed source estimations identified bilateral posterior sylvian regions as the principal contributors to pre-stimulus beta oscillations. Activity within the left posterior sylvian region was significantly stronger before accurate than inaccurate TOJ trials. We discuss our results in terms of a modulation of sensory gating mechanisms mediated by beta activity.

The Gaussian assumption in second-order estimation problems in digital communications

This paper deals with the goodness of the Gaussian assumption when designing second-order blind estimationmethods in the context of digital communications. The low- andhigh-signal-to-noise ratio (SNR) asymptotic performance of the maximum likelihood estimator—derived assuming Gaussiantransmitted symbols—is compared with the performance of the optimal second-order estimator, which exploits the actualdistribution of the discrete constellation. The asymptotic study concludes that the Gaussian assumption leads to the optimalsecond-order solution if the SNR is very low or if the symbols belong to a multilevel constellation such as quadrature-amplitudemodulation (QAM) or amplitude-phase-shift keying (APSK). On the other hand, the Gaussian assumption can yield importantlosses at high SNR if the transmitted symbols are drawn from a constant modulus constellation such as phase-shift keying (PSK)or continuous-phase modulations (CPM). These conclusions are illustrated for the problem of direction-of-arrival (DOA) estimation of multiple digitally-modulated signals.

Motion estimation using higher-order statistics

The objective of this paper is to introduce a fourth-order cost function of the displaced frame difference (DFD) capable of estimatingmotion even for small regions or blocks. Using higher than second-orderstatistics is appropriate in case the image sequence is severely corruptedby additive Gaussian noise. Some results are presented and compared to those obtained from the mean kurtosis and the mean square error of the DFD.

Wigner higher-order spectra: definition, properties, computation and application to transient signal analysis

The Wigner higher order moment spectra (WHOS)are defined as extensions of the Wigner-Ville distribution (WD)to higher order moment spectra domains. A general class oftime-frequency higher order moment spectra is also defined interms of arbitrary higher order moments of the signal as generalizations of the Cohen’s general class of time-frequency representations. The properties of the general class of time-frequency higher order moment spectra can be related to theproperties of WHOS which are, in fact, extensions of the properties of the WD. Discrete time and frequency Wigner higherorder moment spectra (DTF-WHOS) distributions are introduced for signal processing applications and are shown to beimplemented with two FFT-based algorithms. One applicationis presented where the Wigner bispectrum (WB), which is aWHOS in the third-order moment domain, is utilized for thedetection of transient signals embedded in noise. The WB iscompared with the WD in terms of simulation examples andanalysis of real sonar data. It is shown that better detectionschemes can be derived, in low signal-to-noise ratio, when theWB is applied.

Second-order parameter estimation

This work provides a general framework for the design of second-order blind estimators without adopting anyapproximation about the observation statistics or the a prioridistribution of the parameters. The proposed solution is obtainedminimizing the estimator variance subject to some constraints onthe estimator bias. The resulting optimal estimator is found todepend on the observation fourth-order moments that can be calculatedanalytically from the known signal model. Unfortunately,in most cases, the performance of this estimator is severely limitedby the residual bias inherent to nonlinear estimation problems.To overcome this limitation, the second-order minimum varianceunbiased estimator is deduced from the general solution by assumingaccurate prior information on the vector of parameters.This small-error approximation is adopted to design iterativeestimators or trackers. It is shown that the associated varianceconstitutes the lower bound for the variance of any unbiasedestimator based on the sample covariance matrix.The paper formulation is then applied to track the angle-of-arrival(AoA) of multiple digitally-modulated sources by means ofa uniform linear array. The optimal second-order tracker is comparedwith the classical maximum likelihood (ML) blind methodsthat are shown to be quadratic in the observed data as well. Simulationshave confirmed that the discrete nature of the transmittedsymbols can be exploited to improve considerably the discriminationof near sources in medium-to-high SNR scenarios.

Market entry order and competitive advantage of the firm

A firm that wishes to launch a new product to the market is faced with a difficult task of deciding what the best moment for the launch is. Timing may also be critical when a firm plans to adopt new processes or intends to head for new markets. The critical question the firm needs to tackle is whether it will try to reach the so-called first-mover advantage by acting earlier than its rivals. The first-mover position may reward the entrant with various opportunities to gain competitive advantage over later movers. However, there are also great risks involved in the early market entry, and sometimes the very first entrant fails even before the followers enter the market. The follower, on the other hand, may be able to free-ride on the earlier entrants' investments and gain from the languished uncertainties that characterize the new markets. According to the current understanding the occurrence of entry order advantages depends not only on the mechanism and attributes in the firm's environment that provide the initial opportunities but also on the firm's ability to capitalize on these advantage opportunities. This study contributes to this discussion by analyzing the linkages between the asset base of the firm, characteristics of the operating environment and the firm's entry timing orientation. To shed light on the relationship between the entry timing strategy and competitive advantage, this study utilizes the concept of entry timing orientation. The rationale for choosing this type of approach arises from the inability of previously employed research tools to reach the underlying factors that result in entry timing advantage. The work consists of an introductory theoretical discussion on entry timing advantages and of four research publication. The empirical findings support the understanding that entry timing advantage is related to the characteristics of the firm's operating environment but may also be related to firm-specific factors. This in turn suggests that some of the traditional ways of detecting and measuring first-mover advantage - which to some extent ignore these dimensions - may be outdated.

Ground-state order and spin-lattice coupling in tetrahedral spin systems Cu2Te2O5X2 (X = Br or Cl)

High-resolution ac susceptibility and thermal conductivity measurement on Cu2Te2O5X2 (X=Br,Cl) single crystals are reported. For Br-sample, sample dependence prevents one from distinguishing between possibilities of magnetically ordered and spin-singlet ground states. In Cl-sample a three-dimensional transition at 18.5 K is accompanied by almost isotropic behavior of susceptibility and almost switching behavior of thermal conductivity. Thermal conductivity studies suggest the presence of a tremendous spin-lattice coupling characterizing Cl- but not Br-sample. Below the transition Cl-sample is in a complex magnetic state involving AF order but also the elements consistent with the presence of a gap in the excitation spectrum.

Item master management in the engineer-to-order supply chain

Diplomityöntavoitteena on tutkia, kuinka nimiketiedon hallinnalla voidaan parantaa kustannustehokkuutta projektiohjautuvassa toimitusketjussa. Työn kohdeyritys on Konecranes Oyj:n tytäryhtiö Konecranes Heavy Lifting Oy. Nimiketiedon hallinta liittyy läheisesti tuotetiedon hallintaan. Teoriaosassa käsitellään toimitusketjuympäristön tekijöitä, modulaarisuuden ja asiakaskohtaisuuden ongelmallisuutta sekä informaatiovirran vaikutuksia eri toiminnoissa. Yritysosassa vertaillaan konsernitason kahta liiketoiminta-aluetta strategiavalintojen, tuotteiden modulaarisuuden sekä tilaus-toimitusprosessissa liikkuvan nimikeinformaation perusteella. Diplomityön tuloksena annetaan suuntaviivat; nimikemassan eheytykseen, strategisten nimikkeiden tunnistamiseen ja määrittämiseen, nimikkeiden hallintaan sekä master-datan sijoittamiseen tietojärjestelmäympäristöön.

Development of Order-Delivery Process in Purchasing

Diplomityön tavoitteena oli kehittää Fazer Suklaan oston tilaus-toimitusprosesseja, jotta raaka-aineet ja pakkausmateriaalit pystytään hoitamaan mahdollisimman tehokkaasti. Ensin selvitettiin kirjallisuuden avulla tilaus-toimitusprosessin päävaiheet ja niihin vaikuttavat tekijät. Empiirisessä osassa lähdettiin liikkeelle käymällä läpi Fazer Suklaan oston nykytilanne, joka tehtiin ostajille suunnatun aikaselvityksen, haastatteluiden ja nykyisten tilaus-toimitusprosessien kuvaamisen avulla. Tavoitetilanteen rakentaminen aloitettiin ostettavien materiaalien ja toimittajien luokittelemisella. Tämän perusteella nämä materiaalit voitiin jakaa kolmen eri tilaus toimitusprosessin alle. Automaattisessa tilaus-toimitusprosessissa eri vaiheet automatisoidaan yhdessäavain toimittajien kanssa. Puoliautomaattinen prosessi perustuu systeemiin, jossa toimittaja näkee internetin kautta Fazerin tuotantosuunnitelman ja tekee tämän perusteella materiaalien täydennykset. Yksinkertaisessa prosessissa ostoarvoltaan alhaiset materiaalit hoidetaan mahdollisimman lähellä käyttöpistettä ja prosessin vaiheet tehdään mandollisimman pienellä työmäärällä. Tavoiteprosessien implementoinnilla todettiin suurimmiksi eduiksi prosessivaiheiden vähentyminen ja manuaalisen työn automatisoituminen. Tätä kautta saatiin prosessin eri vaiheiden työmäärää vähennettyä, sekä alennettua varastotasoja ja näin tilaus toimitusprosessin kokonaiskustannuksia pystyttiin pienentämään.

Interhemispheric coupling between the posterior sylvian regions impacts successful auditory temporal order judgment.

Accurate perception of the temporal order of sensory events is a prerequisite in numerous functions ranging from language comprehension to motor coordination. We investigated the spatio-temporal brain dynamics of auditory temporal order judgment (aTOJ) using electrical neuroimaging analyses of auditory evoked potentials (AEPs) recorded while participants completed a near-threshold task requiring spatial discrimination of left-right and right-left sound sequences. AEPs to sound pairs modulated topographically as a function of aTOJ accuracy over the 39-77ms post-stimulus period, indicating the engagement of distinct configurations of brain networks during early auditory processing stages. Source estimations revealed that accurate and inaccurate performance were linked to bilateral posterior sylvian regions activity (PSR). However, activity within left, but not right, PSR predicted behavioral performance suggesting that left PSR activity during early encoding phases of pairs of auditory spatial stimuli appears critical for the perception of their order of occurrence. Correlation analyses of source estimations further revealed that activity between left and right PSR was significantly correlated in the inaccurate but not accurate condition, indicating that aTOJ accuracy depends on the functional decoupling between homotopic PSR areas. These results support a model of temporal order processing wherein behaviorally relevant temporal information--i.e. a temporal 'stamp'--is extracted within the early stages of cortical processes within left PSR but critically modulated by inputs from right PSR. We discuss our results with regard to current models of temporal of temporal order processing, namely gating and latency mechanisms.

La Milícia Nacional de Lleida al Trienni Liberal

En aquest treball d'investigació dedicat a la Milícia Nacional de la ciutat de Lleida durant el Trienni Liberal s'ha pretés estudiar la seva implantació, l'evolució, la dinàmica interna i la composició socioprofessional dels seus membres. La Milícia a l'inici del període liberal va tenir dificultats per formar-se. Aquest fet ens va indicar que no hi havia molt individus amb tendència liberal i que la major part de la població treballava en l'àmbit agrari, o sigui, no hi havia gaire comerç i els individus dedicats a les professionals liberals o no eren molts quantitativament o no tenien massa poder polític i econòmic. Tot i que la consolidació i l'actuació del bàndol reialista va potenciar l'organització de la Milícia a la ciutat lleidatana. Per aturar l'avanç dels seguidors absolutistes, l'abril de l'any 1821 es va crear una nova milícia, aquesta vegada de caire voluntari. La Milícia Local va triomfar perquè la seva principal característica residia en el voluntarietat. Les persones que es van apuntar ho van fer per motius derivats de les seves pròpies conviccions polítiques. Finalment apuntar que la Milícia Nacional a Lleida a les darreries del règim liberal va aconseguir mantenir el poder constitucional fins l'arribada dels Cent Mil Fills de Sant Lluis.