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User readiness to interact with information systems - a human activity perspectiveSun, 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.
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Asymptotic Sum Rate Analysis Over Double Scattering Channels With MMSE Estimation and MRT PrecodingYe, 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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