Advanced receivers for next generation wireless communication systems

Despite extensive progress on the theoretical aspects of spectral efficient communication systems, hardware impairments, such as phase noise, are the key bottlenecks in next generation wireless communication systems. The presence of non-ideal oscillators at the transceiver introduces time varying phase noise and degrades the performance of the communication system. Significant research literature focuses on joint synchronization and decoding based on joint posterior distribution, which incorporate both the channel and code graph. These joint synchronization and decoding approaches operate on well designed sum-product algorithms, which involves calculating probabilistic messages iteratively passed between the channel statistical information and decoding information. Channel statistical information, generally entails a high computational complexity because its probabilistic model may involve continuous random variables. The detailed knowledge about the channel statistics for these algorithms make them an inadequate choice for real world applications due to power and computational limitations. In this thesis, novel phase estimation strategies are proposed, in which soft decision-directed iterative receivers for a separate A Posteriori Probability (APP)-based synchronization and decoding are proposed. These algorithms do not require any a priori statistical characterization of the phase noise process. The proposed approach relies on a Maximum A Posteriori (MAP)-based algorithm to perform phase noise estimation and does not depend on the considered modulation/coding scheme as it only exploits the APPs of the transmitted symbols. Different variants of APP-based phase estimation are considered. The proposed algorithm has significantly lower computational complexity with respect to joint synchronization/decoding approaches at the cost of slight performance degradation. With the aim to improve the robustness of the iterative receiver, we derive a new system model for an oversampled (more than one sample per symbol interval) phase noise channel. We extend the separate APP-based synchronization and decoding algorithm to a multi-sample receiver, which exploits the received information from the channel by exchanging the information in an iterative fashion to achieve robust convergence. Two algorithms based on sliding block-wise processing with soft ISI cancellation and detection are proposed, based on the use of reliable information from the channel decoder. Dually polarized systems provide a cost-and spatial-effective solution to increase spectral efficiency and are competitive candidates for next generation wireless communication systems. A novel soft decision-directed iterative receiver, for separate APP-based synchronization and decoding, is proposed. This algorithm relies on an Minimum Mean Square Error (MMSE)-based cancellation of the cross polarization interference (XPI) followed by phase estimation on the polarization of interest. This iterative receiver structure is motivated from Master/Slave Phase Estimation (M/S-PE), where M-PE corresponds to the polarization of interest. The operational principle of a M/S-PE block is to improve the phase tracking performance of both polarization branches: more precisely, the M-PE block tracks the co-polar phase and the S-PE block reduces the residual phase error on the cross-polar branch. Two variants of MMSE-based phase estimation are considered; BW and PLP.

The impact of the language barrier on the management of multinational companies : a case study and survey, based exploration of the impact of the language barrier on the strategies, policies and systems by which multinational companies manage their subsidaries

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.

Examining the information and communication technologies enabling servitized manufacture

Services-led competitive strategies are critically important to Western manufacturers. This paper contributes to our basic knowledge of such strategies by examining the enabling information and communication technologies that successfully servitized manufacturers appear to be adopting. Although these are preliminary findings from a longer-term research programme, through this paper we seek to offer immediate assistance to manufacturers who wish to understand how they might exploit the servitization movement.

Evolution of competing strategies in a threshold model for task allocation

A nature inspired decentralised multi-agent algorithm is proposed to solve a problem of distributed task allocation in which cities produce and store batches of different mail types. Agents must collect and process the mail batches, without global knowledge of their environment or communication between agents. The problem is constrained so that agents are penalised for switching mail types. When an agent process a mail batch of different type to the previous one, it must undergo a change-over, with repeated change-overs rendering the agent inactive. The efficiency (average amount of mail retrieved), and the flexibility (ability of the agents to react to changes in the environment) are investigated both in static and dynamic environments and with respect to sudden changes. New rules for mail selection and specialisation are proposed and are shown to exhibit improved efficiency and flexibility compared to existing ones. We employ a evolutionary algorithm which allows the various rules to evolve and compete. Apart from obtaining optimised parameters for the various rules for any environment, we also observe extinction and speciation.

Strategies for public engagement on environmental matters:you can lead a horse to water, but can you make it drink?

With no tangible evidence of widespread public engagement in the UK on matters relating to the environment, this article assesses the benefits of adopting the principles of key theoretical models on learning (e.g., Kolb's Experiential Model) in environmental campaigns. In addition, in order to facilitate the transition from environmental knowledge/awareness, to the adoption of proenvironmental behavior, the article reviews some of the key internal and external drivers to achieving sustained behavioral change.

Leadership in high-value services for manufacturers:information and communication technologies and the delivery of advanced services

Services-led competitive strategies are critically important to western manufacturers. This paper contributes to our foundational knowledge of such strategies by examining the enabling information and communication technologies that successfully servitized manufacturers appear to be adopting. Although these are preliminary findings from a longer-term research programme, through this article we seek to offer immediate assistance to manufacturers who wish to understand how they might exploit the servitization movement.

Legitimacy building strategies in conditions of discretionary legal enforcement:a logic of social action approach

The present study explores strategies used to legitimize the transfer of organizational practices in a situation of institutional upheaval. We apply the logic of social action (Risse, 2000) to analyze the effectiveness of consequence-based action and communication-based action, in terms of higher coordination, lower conflict, and overall higher economic performance. Consequence-based legitimation is obtained by using a system of distributor incentives tied to performance of specific tasks, while communicative legitimation can be achieved by recommendations and warnings. Our setting is an export channel to European emerging economies. Our results indicate that in the absence of legitimacy, as manifested in discretionary legal enforcement, consequence-based legitimation is more effective than communicative legitimation in reducing conflict, increasing coordination, and ultimately in improving the performance of the export dyad. © 2014 Elsevier Inc.

Strategies to optimize the impact of nutritional surveys and epidemiological studies

The development of nutrition and health guidelines and policies requires reliable scientific information. Unfortunately, theoretical considerations and empirical evidence indicate that a large percentage of science-based claims rely on studies that fail to replicate. The session "Strategies to Optimize the Impact of Nutrition Surveys and Epidemiological Studies" focused on the elements of design, interpretation, and communication of nutritional surveys and epidemiological studies to enhance and encourage the production of reliable, objective evidence for use in developing dietary guidance for the public. The speakers called for more transparency of research, raw data, consistent data-staging techniques, and improved data analysis. New approaches to collecting data are urgently needed to increase the credibility and utility of findings from nutrition epidemiological studies. Such studies are critical for furthering our knowledge and understanding of the effects of diet on health.

Direct sequence spread spectrum based PWM strategy for harmonic reduction and communication

Switched mode power supplies (SMPSs) are essential components in many applications, and electromagnetic interference is an important consideration in the SMPS design. Spread spectrum based PWM strategies have been used in SMPS designs to reduce the switching harmonics. This paper proposes a novel method to integrate a communication function into spread spectrum based PWM strategy without extra hardware costs. Direct sequence spread spectrum (DSSS) and phase shift keying (PSK) data modulation are employed to the PWM of the SMPS, so that it has reduced switching harmonics and the input and output power line voltage ripples contain data. A data demodulation algorithm has been developed for receivers, and code division multiple access (CDMA) concept is employed as communication method for a system with multiple SMPSs. The proposed method has been implemented in both Buck and Boost converters. The experimental results validated the proposed DSSS based PWM strategy for both harmonic reduction and communication.

Sustainable consumption: from escape strategies towards real alternatives

Better sustainability policy is supposed to lead to better sustainability performance. Nonetheless, recent research predicts further growth of the ecological footprint and stable ecological deficit in Europe and North America despite their impressive policy efforts (Lenzen et al. 2007) [1]. Similarly, individual strategies result in somewhat reduced load for committed consumers, but this reduction cannot offset the total impact of the socio-economic configuration: consumers in higher income countries tend to pollute more. Comitted consumers "offset" a part of their environmental load by carrying out green purchases. A radical change assumes a change in lifestyle (Shove, 2004) [2]. The conference paper is the first step of the study that aims at measuring the significance of attitude elements as compared to the significance of the socio-economic system on different elements of consumption and environmental aspects This paper focuses on measuring the ecological footprint impacts of consumption in different product groups as well as in different income groups of the society.

Winning Media Strategies in the Time of the Economic Crisis

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.

Enhancing Promotional Strategies through the Use of Web 2.0

We have witnessed a rising interest – by both academic and managerial field – in the marketing application of Web 2.0 techniques. Yet the effective impact and change it brings is still unclarified. The importance of Web 2.0 is constantly on the rise. We see consumers join social networks, using social tools in an ever greater number, therefor it gives companies a new and effective tool for marketing communication and other marketing-related activities. In our research, we first aim to clarify the definition and boundaries of Web 2.0. Then through a literature review we collect some of the most important areas of marketing to be affected by this seemingly technological change. We also have a brief overview of challenges and risks firms face in this new environment.

Detecting deception: Identifying differences in liars' and truth tellers' verbal strategies

Deception research has traditionally focused on three methods of identifying liars and truth tellers: observing non-verbal or behavioral cues, analyzing verbal cues, and monitoring changes in physiological arousal during polygraph tests. Research shows that observers are often incapable of discriminating between liars and truth tellers with better than chance accuracy when they use these methods. One possible explanation for observers' poor performance is that they are not properly applying existing lie detection methods. An alternative explanation is that the cues on which these methods — and observers' judgments — are based do not reliably discriminate between liars and truth tellers. It may be possible to identify more reliable cues, and potentially improve observers' ability to discriminate, by developing a better understanding of how liars and truth tellers try to tell a convincing story. ^ This research examined (a) the verbal strategies used by truthful and deceptive individuals during interviews concerning an assigned activity, and (b) observers' ability to discriminate between them based on their verbal strategies. In Experiment I, pre-interview instructions manipulated participants' expectations regarding verifiability; each participant was led to believe that the interviewer could check some types of details, but not others, before deciding whether the participant was being truthful or deceptive. Interviews were then transcribed and scored for quantity and type of information provided. In Experiment II, observers listened to a random sample of the Experiment I interviews and rendered veracity judgments; half of the observers were instructed to judge the interviews according to the verbal strategies used by liars and truth tellers and the other half were uninstructed. ^ Results of Experiment I indicate that liars and truth tellers use different verbal strategies, characterized by a differential amount of detail. Overall, truthful participants provided more information than deceptive participants. This effect was moderated by participants' expectations regarding verifiability such that truthful participants provided more information only with regard to verifiable details. Results of Experiment II indicate that observers instructed about liars' and truth tellers' verbal strategies identify them with greater accuracy than uninstructed observers. ^

An investigation of the strategies used by organizations participating in the welfare-to-work network program and correlation of the strategies with the retention data to determine best practices for job retention among former welfare recipients

This ex post facto study (N = 209) examined the relationships between employer job strategies and job retention among organizations participating in Florida welfare-to-work network programs and associated the strategies with job retention data to determine best practices. ^ An internet-based self-report survey battery was administered to a heterogeneous sampling of organizations participating in the Florida welfare-to-work network program. Hypotheses were tested through correlational and hierarchical regression analytic procedures. The partial correlation results linked each of the job retention strategies to job retention. Wages, benefits, training and supervision, communication, job growth, work/life balance, fairness and respect were all significantly related to job retention. Hierarchical regression results indicated that the training and supervision variable was the best predictor of job retention in the regression equation. ^ The size of the organization was also a significant predictor of job retention. Large organizations reported higher job retention rates than small organizations. There was no statistical difference between the types of organizations (profit-making and non-profit) and job retention. The standardized betas ranged from to .26 to .41 in the regression equation. Twenty percent of the variance in job retention was explained by the combination of demographic and job retention strategy predictors, supporting the theoretical, empirical, and practical relevance of understanding the association between employer job strategies and job retention outcomes. Implications for adult education and human resource development theory, research, and practice are highlighted as possible strategic leverage points for creating conditions that facilitate the development of job strategies as a means for improving former welfare workers’ job retention.^