Academic literature on the topic 'Ommunication Systems'

Sharing and exploitation of information resources across a diverse organisation can confer a significant competitive advantage but also can be a substantial challenge in coordinating across structural and specialisation boundaries. This challenge reflects the difficulties traditionally associated with lateral relations, which were recognised by classical organisational theorists but are more pronounced with the emergence of information as a critical resource. Notwithstanding the benefits of information sharing across the organisation, the classical concept of specialisation remains fundamental to organisational theory; thus there is potential for friction between requirements for specialisation and coordination. This research therefore examines information management arrangements to balance specialisation and coordination in a diverse organisation. The research takes advantage of organisational and systems theory literature to appreciate complex information management requirements in terms of differentiation/cohesion and integration/coupling of organisational elements. Information management???s business and technology perspectives define the conceptual framework, within which gaps in the literature are identified and become the focus of the research. The two key research areas are the opportunities enabled by technology for business integration through collaborative decision-making and the management of organisation-wide information technology infrastructure. Collaborative decision-making is an integrating mechanism that can provide balance between specialisation and coordination contingent upon the nature of decision tasks and their organisational context. Propositions associated with an adaptive approach to collaborative decision-making were tested in laboratory experiments, with positive support for the contingency model albeit constrained by individual cognitive variances. Organisations increasingly are adopting centralised approaches to the provision of IT services, with IT governance as an integrating mechanism and a need for multiple business-IT alignments to add value according to the differentiation required by organisational elements. Propositions relating to the adaptation of IT management arrangements based upon organisational characteristics were tested using a multi- iv -discipline approach, which resulted in support for the model although practical difficulties were experienced in the action research component. This research provides a framework for maintaining effective variety of information capabilities commensurate with the diverse organisation???s mission and environment, while also exploiting the synergies and economies of shared information resources for holistic benefits.

This thesis proposes a novel approach for the synthesis of delays for timed systems, in particular in the framework oftimed automata, a model for verifying real-time systems. Our approach relies on the following inverse method: given a reference valuation of the parameters, we synthesize a constraint on the parameters, guaranteeing the same timeabstract linear behavior as for the reference valuation. This gives a criterion of robustness to the system. By iterating this inverse method on various points of a bounded parameter domain, we are then able to partition the parametric space into good and bad zones, with respect to a given property one wants to verify. This gives a behavioral cartography of the system. This method extended to probabilistic systems allows to preserve minimum and maximum probabilities of reachability properties. We also present variants of the inverse method for directed weighted graphs and Markov Decision Processes. Several prototypes have been implemented; in particular, IMITATOR II implements the inverse method and the cartography for timed automata. It allowed us to synthesize parameter values for several case studies such as an abstract model of a memory circuit sold by the chipset manufacturer ST-Microelectronics, and various communication protocols.

碩士
國立雲林科技大學
電機工程系碩士班
94
DCSK is a non-coherent modulation and demodulation technique which is designed by using the chaotic signal as the carrier. Due to the characteristic of multi-frequency of chaotic communication, a good performance of multi-path-fading is expected for wireless communication. In order to obtain the good performance of chaotic communication system in time-invariant channel and time-variant channel, the thesis is to presented an adaptive channel equalizer and a technique of channel coding to overcome channel effect and noise especially AWGN. In this thesis, we not only apply the numerical simulation to demonstrate proposed results but also transmit a some digital images and voices in different communication systems to verify performance is satisfying in different environments.