986 resultados para Communications strategies


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In this thesis, we consider four different scenarios of interest in modern satellite communications. For each scenario, we will propose the use of advanced solutions aimed at increasing the spectral efficiency of the communication links. First, we will investigate the optimization of the current standard for digital video broadcasting. We will increase the symbol rate of the signal and determine the optimal signal bandwidth. We will apply the time packing technique and propose a specifically design constellation. We will then compare some receiver architectures with different performance and complexity. The second scenario still addresses broadcast transmissions, but in a network composed of two satellites. We will compare three alternative transceiver strategies, namely, signals completely overlapped in frequency, frequency division multiplexing, and the Alamouti space-time block code, and, for each technique, we will derive theoretical results on the achievable rates. We will also evaluate the performance of said techniques in three different channel models. The third scenario deals with the application of multiuser detection in multibeam satellite systems. We will analyze a case in which the users are near the edge of the coverage area and, hence, they experience a high level of interference from adjacent cells. Also in this case, three different approaches will be compared. A classical approach in which each beam carries information for a user, a cooperative solution based on time division multiplexing, and the Alamouti scheme. The information theoretical analysis will be followed by the study of practical coded schemes. We will show that the theoretical bounds can be approached by a properly designed code or bit mapping. Finally, we will consider an Earth observation scenario, in which data is generated on the satellite and then transmitted to the ground. We will study two channel models, taking into account one or two transmit antennas, and apply techniques such as time and frequency packing, signal predistortion, multiuser detection and the Alamouti scheme.

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The Foot-and-Mouth Disease (FMD) outbreak of 2001 in the UK was completely unprecedented in its scale and severity, with over four million animals culled and a cost to the Exchequer of over £4 billion. Local authorities were at the front line in dealing with the outbreak, in coordinating the cull of livestock, the disposal of carcasses as well as attempting to deal with its aftermath and, in particular, the impact on the wider rural economy. This article examines the impacts of this crisis on three local authorities, Devon, Herefordshire and Cumbria. It examines how far the crisis acted as a catalyst in developing strategies to deal with a future outbreak as well as new local initiatives to promote regeneration in the areas most adversely affected. It focuses on developments that can be directly attributed to the crisis and shows that FMD had a considerable impact on communications and 'joined-up' activity within local authorities and with local stakeholders. © 2006, LEPU, South Bank University.

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The thesis begins with a conceptual model of the way that language diversity affects the strategies, organisation and subsidiary control policies of multinational companies. The model is based solely on the researcher'’ personal experience of working in a variety of international management roles, but in Chapter 2 a wide-ranging review of related academic literature finds evidence to support the key ideas. The model is developed as a series of propositions which are tested in a comparative case study, refined and then re-tested in a global survey of multinational subsidiaries. The principal findings of the empirical phases of the thesis endorse the main tenets of the model: - That language difference between parent and subsidiary will impair communication, create mistrust and impede relationship development. - That subsequently the feelings of uncertainty, suspicion and mistrust will influence the decisions taken by the parent company. - They will have heightened sensitivity to language issues and will implement policies to manage language differences. - They will adopt low-risk strategies in host countries where they are concerned about language difference. - They will use organisational and manpower strategies to minimise the consequences and risks of the communications problems with the subsidiary. - As a consequence the level of integration and knowledge flow between parent and subsidiary will be curtailed. - They will adopt styles of control that depend least on their ability to communicate with their subsidiary. Although there is adequate support for all of the above conclusions, on some key points the evidence of the Case Studies and Survey is contradictory. The thesis, therefore, closes with an agenda for further research that would address these inconsistencies.

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Mental simulations and analogies have been identified as powerful learning tools for RNPs. Furthermore, visuals in advertising have recently been conceptualized as meaningful sources of information as opposed to peripheral cues and thus may help consumers learn about RNPs. The study of visual attention may also contribute to understanding the links between conceptual and perceptual analyses when learning for a RNP. Two conceptual models are developed. the first model consists of causal relationships between the attributes of advertising stimuli for RNPs and consumer responses, as well as mediating influences. The second model focuses on the role of visual attention in product comprehension as a response to advertising stimuli. Two experiments are conducted: a Web-Experiment and an eye-tracking experiment. The first experiment (858 subjects) examines the effect of learning strategies (mental simulation vs. analogy vs. no analogy/no mental simulation) and presentation formats (words vs. pictures) on individual responses. The mediating role of emotions is assessed. The second experiment investigates the effect of learning strategies and presentation formats on product comprehension, along with the role of attention (17 subjects). The findings from experiment 1 indicate that learning strategies and presentation formats can either enhance or undermine the effect of advertising stimuli on individual responses. Moreover, the nature of the product (i.e. hedonic vs. utilitarian vs. hybrid) should be considered when designing communications for RNPs. The mediating role of emotions is verified. Experiment 2 suggests that an increase in attention to the message may either reflect enhanced comprehension or confusion.

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Based on a review of the extant literature, a conceptual framework for analyzing the associations between managerial strategies (internal communications, empowerment, supportive leadership and professional development), employee job attitudes (organizational commitment and job satisfaction) and prosocial service behaviours (PSBs) is developed. The authors explore the relevance of the proposed conceptual model and testable propositions regarding the associations between managerial strategies, employee attitudes and PSBs by conducting in-depth interviews of FLEs in a travel service organization. Based on the findings of the in-depth interviews, the relationships between managerial strategies, job attitudes and PSBs in the conceptual framework are largely supported.

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(Summary of: Varbanova-Dencheva, K. Intellectual communications and contemporarly technologies. Alternatives of the science libraries. Sofia, Marin Drinov academic publishing house. 2003, 114p. ) The new technologies and the globalization are the factors which have brought essential changes in human society and its environment. The unceasing dynamic changes imposed new strategies for survival and prosperity of institutions and people in the new conditions. The spheres with greatest potential for achieving competition priority are compatible to the fastness of research results implementation in each field of human activity. The extended knowledge requires narrower specialization as well as interdisciplinarity to solve the arising problems. The new research fields and trends are a synthesis of science and high technologies determined by the new discoveries. The present study aims at finding answers to the questions about the place of science library in the dynamic restructuring of research environment. The necessity of transformation of the scientific library’s genetically set functions from a guardian of the achieved knowledge to an active participant in the creation of new knowledge is a natural consequence of the processes and tendencies of the social medium. The priorities of Europe and USA for intensive creation of knowledge economics are at the first place and this requires intensification of that research an integral part of which are the new communications realized at a new technological level.

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Based on a review of the extant literature, a conceptual framework for analyzing the associations between managerial strategies (internal communications, empowerment, supportive leadership and professional development), employee job attitudes (organizational commitment and job satisfaction) and prosocial service behaviours (PSBs) is developed. The authors explore the relevance of the proposed conceptual model and testable propositions regarding the associations between managerial strategies, employee attitudes and PSBs by conducting in-depth interviews of FLEs in a travel service organization. Based on the findings of the in-depth interviews, the relationships between managerial strategies, job attitudes and PSBs in the conceptual framework are largely supported.

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At the time of the economic crisis cutting marketing and media expenses is a common corporate reaction. While this reaction is rather obvious, this may not be the winning option. To find out more about successful media strategies authors conducted a broad, multiple method research, including interviews with industry experts (N=6, leading decision makers), scrutiny of consumer narratives (N=100), content analysis of forum and blog entries (N=7086 comments) and focus group interviews (N=4). Research findings point to realignment in media spending namely better-targeted communications programs and more fragmented media choice, and besides, show the increasing role of audience participation, too. Authors argue that careful managerial efforts for harmonizing consumer problems and advertising content may result in finding the path from problem level to desired level in marketing communication practices even in crisis periods.

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Modern power networks incorporate communications and information technology infrastructure into the electrical power system to create a smart grid in terms of control and operation. The smart grid enables real-time communication and control between consumers and utility companies allowing suppliers to optimize energy usage based on price preference and system technical issues. The smart grid design aims to provide overall power system monitoring, create protection and control strategies to maintain system performance, stability and security. This dissertation contributed to the development of a unique and novel smart grid test-bed laboratory with integrated monitoring, protection and control systems. This test-bed was used as a platform to test the smart grid operational ideas developed here. The implementation of this system in the real-time software creates an environment for studying, implementing and verifying novel control and protection schemes developed in this dissertation. Phasor measurement techniques were developed using the available Data Acquisition (DAQ) devices in order to monitor all points in the power system in real time. This provides a practical view of system parameter changes, system abnormal conditions and its stability and security information system. These developments provide valuable measurements for technical power system operators in the energy control centers. Phasor Measurement technology is an excellent solution for improving system planning, operation and energy trading in addition to enabling advanced applications in Wide Area Monitoring, Protection and Control (WAMPAC). Moreover, a virtual protection system was developed and implemented in the smart grid laboratory with integrated functionality for wide area applications. Experiments and procedures were developed in the system in order to detect the system abnormal conditions and apply proper remedies to heal the system. A design for DC microgrid was developed to integrate it to the AC system with appropriate control capability. This system represents realistic hybrid AC/DC microgrids connectivity to the AC side to study the use of such architecture in system operation to help remedy system abnormal conditions. In addition, this dissertation explored the challenges and feasibility of the implementation of real-time system analysis features in order to monitor the system security and stability measures. These indices are measured experimentally during the operation of the developed hybrid AC/DC microgrids. Furthermore, a real-time optimal power flow system was implemented to optimally manage the power sharing between AC generators and DC side resources. A study relating to real-time energy management algorithm in hybrid microgrids was performed to evaluate the effects of using energy storage resources and their use in mitigating heavy load impacts on system stability and operational security.

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We investigate device-to-device (D2D) communication underlaying cellular networks with M-antenna base stations. We consider both beamforming (BF) and interference cancellation (IC) strategies under quantized channel state information (CSI), as well as, perfect CSI. We derive tight closed-form approximations of the ergodic achievable rate which hold for arbitrary transmit power, location of users and number of antennas. Based on these approximations, we derive insightful asymptotic expressions for three special cases namely high signal-to-noise (SNR), weak interference, and large M. In particular, we show that in the high SNR regime a ceiling effect exists which depends on the received signal-to-interference ratio and the number of antennas. Moreover, the achievable rate scales logarithmically with M. The ergodic achievable rate is shown to scale logarithmically with SNR and the antenna number in the weak interference case. When the BS is equipped with large number of antennas, we find that the ergodic achievable rate under quantized CSI reaches a saturated value, whilst it scales as log2M under perfect CSI.

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The paper describes the strategies for Congestion and Incident Management (CIM) on the basis of Automatic Congestion and Incident Detection (ACID) that COSMOS will develop, implement in SCOOT, UTOPIA and MOTION, and validate and demonstrate in London, Piraeus and Torino. Four levels of operation were defined for CIM: strategies, tactics, tools and realisation. The strategies for CIM form the top level of this hierarchy. They have to reflect the strategic requirements of the system operators. The tactics are the means that can be employed by the strategies to achieve particular goals in particular situations. The tools that are used by the tactics relate to the elements of the signal plan and the ways in which they can be modified. Strategies, tactics and tools are generally common to all three systems, while the realisation of individual strategies and tactical decisions, through the use of particular common sets of tools, will generally be system specific. For the covering abstract, see IRRD 490001.

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The energy consumption by ICT (Information and Communication Technology) equipment is rapidly increasing which causes a significant economic and environmental problem. At present, the network infrastructure is becoming a large portion of the energy footprint in ICT. Thus the concept of energy efficient or green networking has been introduced. Now one of the main concerns of network industry is to minimize energy consumption of network infrastructure because of the potential economic benefits, ethical responsibility, and its environmental impact. In this paper, the energy management strategies to reduce the energy consumed by network switches in LAN (Local Area Network) have been developed. According to the lifecycle assessment of network switches, during usage phase, the highest amount of energy consumed. The study considers bandwidth, link load and traffic matrixes as input parameters which have the highest contribution in energy footprint of network switches during usage phase and energy consumption as output. Then with the objective of reducing energy usage of network infrastructure, the feasibility of putting Ethernet switches hibernate or sleep mode was investigated. After that, the network topology was reorganized using clustering method based on the spectral approach for putting network switches to hibernate or switched off mode considering the time and communications among them. Experimental results show the interest of this approach in terms of energy consumption

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Modern power networks incorporate communications and information technology infrastructure into the electrical power system to create a smart grid in terms of control and operation. The smart grid enables real-time communication and control between consumers and utility companies allowing suppliers to optimize energy usage based on price preference and system technical issues. The smart grid design aims to provide overall power system monitoring, create protection and control strategies to maintain system performance, stability and security. This dissertation contributed to the development of a unique and novel smart grid test-bed laboratory with integrated monitoring, protection and control systems. This test-bed was used as a platform to test the smart grid operational ideas developed here. The implementation of this system in the real-time software creates an environment for studying, implementing and verifying novel control and protection schemes developed in this dissertation. Phasor measurement techniques were developed using the available Data Acquisition (DAQ) devices in order to monitor all points in the power system in real time. This provides a practical view of system parameter changes, system abnormal conditions and its stability and security information system. These developments provide valuable measurements for technical power system operators in the energy control centers. Phasor Measurement technology is an excellent solution for improving system planning, operation and energy trading in addition to enabling advanced applications in Wide Area Monitoring, Protection and Control (WAMPAC). Moreover, a virtual protection system was developed and implemented in the smart grid laboratory with integrated functionality for wide area applications. Experiments and procedures were developed in the system in order to detect the system abnormal conditions and apply proper remedies to heal the system. A design for DC microgrid was developed to integrate it to the AC system with appropriate control capability. This system represents realistic hybrid AC/DC microgrids connectivity to the AC side to study the use of such architecture in system operation to help remedy system abnormal conditions. In addition, this dissertation explored the challenges and feasibility of the implementation of real-time system analysis features in order to monitor the system security and stability measures. These indices are measured experimentally during the operation of the developed hybrid AC/DC microgrids. Furthermore, a real-time optimal power flow system was implemented to optimally manage the power sharing between AC generators and DC side resources. A study relating to real-time energy management algorithm in hybrid microgrids was performed to evaluate the effects of using energy storage resources and their use in mitigating heavy load impacts on system stability and operational security.

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Introduction: The changes in the health area and the set of structural changes in the nursing profession and career interfere in the dynamics and stability of the future of the nurses. Objectives: To study the influence of organizational and professional commitment of the nurses in the strategies of conflict resolution. Methods: This is a quantitative, transversal and non-experimental research, following a descriptive-correlational way. Data were obtained by applying a questionnaire to nurses that work on different types of Primary Health Care Units. As measuring instruments we used three scales that grouped a total of nine subscales used to evaluate: the organizational commitment, the professional commitment and the strategies of conflict resolution. Results: The majority of nurses present moderate scores of organizational and Professional commitment with higher affective commitment to the normative commitment or instrumental commitment and feel that nursing is an interesting and challenging profession, but personal and social perception of nursing relevance is moderately weak. Nurses adopt the domination conflict resolution strategies and accommodation over the head and less integrative strategies and commitment. With subordinates more nurses adopt the avoidance strategy. When the conflictual situation arises with colleagues more endow the integrative strategies and commitment and less domination strategy. The organizational and professional commitment is significantly associated with some solving strategies conflict adopted by nurses as the conflictual situation arises with the boss, with subordinates or colleagues. Some dimensions of organizational commitment and professional foretell to significantly shape the adoption of conflict resolution strategy adopted.