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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

User readiness to interact with information systems - a human activity perspective

Sun, Jun 30 October 2006 (has links)
This study focuses on how and why people become ready to interact with certain information systems (IS) based on their previous experiences with the same and/or similar systems. User-system interaction can be regarded as a mediated and collaborative human activity between a user and a system with the motive of transforming raw information into useful outcome. Using Activity Theory as a paradigm, this study conceptualizes a user-system interaction model that specifies the mediating relationships involved. Based on the user-system interaction model, this study proposes a psychological construct, Information System Interaction Readiness (ISIR), that indicates how an individual is prepared and willing to interact with a system within a user context. This construct advances a developmental view of how previous IS experiences may affect user future behavior. Compared with other constructs as predictors of user behavior, such as computer self-efficacy and intention to use, ISIR takes how IS user behavior is mediated into account. To operationalize and measure the ISIR construct, this study develops a measurement instrument for ISIR using the technique of facet analysis and the semantic differential scale type. To explore how user experiences with a system lead to the formation of ISIR, this study identifies the psychological antecedents of ISIR. This enables the discussion of how general IS capabilities, including interactivity, personalization and context-awareness, may affect ISIR through these antecedents. Because ISIR is a user-, system- and context-specific construct, this study also identifies and discusses the personal and situational factors that may affect ISIR. Putting all these relationships together results in a research framework of ISIR. To validate the ISIR measurement instrument and test the ISIR research framework, several laboratory studies were conducted. The results indicated that the ISIR instrument was valid and the ISIR framework was sound. Finally, the contributions and limitations of this study are discussed.
2

Asymptotic Sum Rate Analysis Over Double Scattering Channels With MMSE Estimation and MRT Precoding

Ye, Jia 04 1900 (has links)
This thesis investigates the performance of a multi-user multiple-input single- output (MISO) system considering maximum ratio transmission (MRT) downlink precoding. The transmitted signal from the base station (BS) to each user is as- sumed to experience the double scattering channel. We adopt the minimum-mean- square-error (MMSE) channel estimator for the proposed model. Within this setting, we are interested in deriving tight approximations of the ergodic rate assuming the number of BS antennas, users, and scatterers grow large with the same pace. Under the special multi-keyhole channels, these deterministic equivalents are expressed in more simplified closed-form expressions. The simplified expressions reveal that unlike the standard Rayleigh channel in which the SINR grows as as O(N/k), the SINR associated with a multi-keyhole channel scales as O(S/N). This particularly shows that the K reaped gains of the large-scale MIMO over double scattering channels do not linearly increase with the number of antennas and are limited by the number of scatterers. We further show that the derived asymptotic results match the simulation results closely under moderate system dimensions and provide some useful insights into the interplay between N, K and S.

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