Intra-excitonic relaxation dynamics in ZnO

The temperature and carrier-density dependent excitonic relaxation in bulk ZnO is studied by means of time-resolved photoluminescence. A rate-equation model is used to analyze the population dynamics and the transitions between different exciton states. Intra-excitonic (n=1) to (n=2) relaxation is clearly identified at low excitation densities and lattice temperatures with a characteristic time constant of 6±0.5 ps

Optical properties of MgZnO alloys: Excitons and exciton-phonon complexes

The characteristics of the excitonic absorption and emission around the fundamental bandgap of wurtzite Mg(x)Zn(1-x)O grown on c-plane sapphire substrates by plasma assisted molecular beam epitaxy with Mg contents between x = 0 and x = 0.23 are studied using spectroscopic ellipsometry and photoluminescence (PL) measurements. The ellipsometric data were analyzed using a multilayer model yielding the dielectric function (DF). The imaginary part of the DF for the alloys exhibits a pronounced feature which is attributed to exciton-phonon coupling (EPC) similar to the previously reported results for ZnO. Thus, in order to determine reliable transition energies, the spectral dependence is analyzed by a model which includes free excitonic lines, the exciton continuum, and the enhanced absorption due to EPC. A line shape analysis of the temperature-dependent PL spectra yielded in particular the emission-related free excitonic transition energies, which are compared to the results from the DF line-shape analysis. The PL linewidth is discussed within the framework of an alloy disorder model

Analysis of a system of description of odors by means of four different multivariate statistical methods

In order to analyze the relationships among 32 descriptors of odors (notes), similarity coefficients were calculated using a data bank of 628 odoriferous products. The simple examination of the similarity matrix (32,32) has shown notes selectively and strongly associated (e.g. camphoraceous-piney and musky-powdery) and others less selectively associated (e.g. floral, green and herbaceous). This analysis was completed by four multivariate statistical methods. Non-linear mapping (NLM) proved to be more efficient than principal coordinates analysis for planar representation of olfactory notes, and has given results similar to those previously obtained using other data and other methods (similar disposition of notes around the central note ‘floral'). Furthermore, the ascending hierarchical taxonomy and the minimal spanning tree were coherent with the NLM representation. These three methods complete each other and constitute a convenient system to analyze odor description

Efficient compact linear programs for network revenue management

We are concerned with computing bid prices in network revenue management using approximate linear programming. It is well-known that affine value function approximations yield bid prices which are not sensitive to remaining capacity. The analytic reduction to compact linear programs allows the efficient computation of such bid prices. On the other hand, capacity-dependent bid prices can be obtained using separable piecewise linear value function approximations. Even though compact linear programs have been derived for this case also, they are still computationally much more expensive compared to using affine functions. We propose compact linear programs requiring substantially smaller computing times while, simultaneously, significantly improving the performance of capacity-independent bid prices. This simplification is achieved by taking into account remaining capacity only if it becomes scarce. Although our proposed linear programs are relaxations of the unreduced approximate linear programs, we conjecture equivalence and provide according numerical support. We measure the quality of an approximation by the difference between the expected performance of an induced policy and the corresponding theoretical upper bound. Using this paradigm in numerical experiments, we demonstrate the competitiveness of our proposed linear programs

WHY DO PEOPLE REJECT TECHNOLOGIES – A LITERATURE-BASED DISCUSSION OF THE PHENOMENA “RESISTANCE TO CHANGE” IN INFORMATION SYSTEMS AND MANAGERIAL PSYCHOLOGY RESEARCH

In 2008, Ford et al. (2008) pointed out for management research, that “it is time to expand our understanding of resistance to change”. Since 1947, when Kurt Lewin discuss the first time the concept of resistance to change within his field theory, managerial psychology researchers have extended, criticized, modified and re-conceptualized the understanding of employees‟ responses to change initiatives. Also information systems research has identified resistance to change as major reason for IT project failures. However, as our analysis in this paper shows, there are a lot of opportunities for IS research to research resistance to IT-induced change. Using a literature review the paper discusses different concepts of resistance to change from managerial psychology and IS research in order to provide a better understanding of resistance to IT-induced change. The paper highlights implications from managerial psychology research to update the understanding of resistance to change in information systems research

On Visitations

In seiner Monographie Transmitted Wounds. Media and the Mediation of Trauma entwickelt Amit Pinchevski die These, dass moderne Massenmedien Trauma sowohl übertragen als auch tilgen können und plädiert dafür, ‚Trauma‘ als moralische Kategorie zu verstehen. Die Publikation verbindet Gedächtnisstudien, medientheoretische Erkenntnisse und Technikgeschichte und streift klinische und psychologische Beiträge zum Begriff ‚Trauma‘. Damit verknüpft Pinchevski verschiedene Perspektiven auf Gewalt und Technik und leistet einen originellen und inspirierenden Beitrag zu diesen Disziplinen.In his monograph, Transmitted Wounds. Media and the Mediation of Trauma, Amit Pinchevski develops the thesis that modern mass media can transmit and obliterate trauma and pleads for using ‘trauma’ as a moral category. His work interlinks memory, communication and technology studies and touches upon clinical and psychological contributions to notions of ‘trauma.’ Combining numerous views on the echoes of violence and technology, Pinchevski contributes in an inventive and inspirational way to those disciplines.      &nbsp

This Was Fort Dade

Fort Dade was born on the twenty-third of December 1836. The announcement read: “A fort will be erected. . . on the Big Withlacoochee, at the point where the Fort King road crosses it, which will bear the name of the gallant and lamented Dade.

INFORMATION QUALITY DIMENSIONS: TWO EXPLORATORY CASE STUDIES WITH ENTERPRISE CONTENT MANAGEMENT SYSTEM USERS

Using two explorative case studies we theorize in this paper about information quality as one variable of the IS success model explaining user satisfaction. We derive four dimensions of information quality which have a diverse and unique impact on user satisfaction: information characteristics, information access and security, information format, and task-information fit. Moreover, we identify contextual factors such as the pace of information change and update, legal and compliance requirements, and employees’ skills which determine the importance of each dimensions for explaining user satisfaction. This more nuanced view of information quality as one component of the IS success model enables a better guidance of organizations in improving information quality to increase user satisfaction. There-fore, several organizational interventions are discussed that can be used to improve information quali-ty by focusing on each of the four unique information quality dimensions separately

The Internet as Additional Secondary Source – First empirical Results for Differentiating the Impact of Secondary Sources on the Intention to use IT

The research about adoption decisions in a household context brought the factor of secondary sources as part of a normative beliefs construct to explain an individual’s behavioral intention. The secondary sources included mass media as TV, radio and newspapers but not the largest global information medium, the internet. With billions of information provided by the internet in every minute it seems to be very likely that this factor depicts an important determinant for an individual’s IT adoption decision as well. So for this reason the aim of our paper is to propose a research model to integrate the explicit influence of the mass medium internet on an individual’s IT adoption decision and to discuss the relationship and interplay between attitude towards an information system, intention to use an information system and the secondary source “Internet”. Furthermore a research description how the influence can be validated is provided and first empirical results are presented