65,127 research outputs found
A probabilistic data association based MIMO detector using joint detection of consecutive symbol vectors
No full textA new probabilistic data association (PDA) approach is proposed for symbol detection in spatial multiplexing multiple-input multiple-output (MIMO) systems. By designing a joint detection (JD) structure for consecutive symbol vectors in the same transmit burst, more a priori information is exploited when updating the estimated posterior marginal probabilities for each symbol per iteration. Therefore the proposed PDA detector (denoted as PDA-JD detector) outperforms the conventional PDA detectors in the context of correlated input bit streams. Moreover, the conventional PDA detectors are shown to be a special case of the PDA-JD detector. Simulations and analyses are given to demonstrate the effectiveness of the new method
Approximate minimum BER power allocation for MIMO-THP system
No full textThis paper proposes a transmit power allocation (TPA) scheme based on multiple-input multiple-output (MIMO) Tomlinson-Harashima precoding (THP) structure, where a TPA matrix is introduced to the conventional MIMO-THP. We analyze the influence of the introduced TPA matrix on the performance of MIMO-THP. The proposed TPA scheme invokes the minimum average uncoded bit-error rate (BER) criterion subjected to a sum-power constraint. During the derivation, we consider the effects of precoding loss factor on the TPA scheme and obtain a closed-form expression of the TPA. Compared to existing TPA methods for MIMO-THP systems, the proposed scheme reduces processing complexity and improves the BER performance
Simulated annealing based multiuser detection for synchronous SDMA system
No full textIn this treatise, a novel Simulated Annealing (SA) based Multi-User Detection (MUD) is proposed in synchronous Space Division Multiple Access (SDMA) system. SA MUD modifies experiential Cooling Schedule (CS) of traditional SA algorithm according to its use in MUD. Moreover, in order to ensure sufficient diversity acquired in the whole Markov chain and to prevent from being trapped at local optima, Uniform Mutation (UM) based trial vector generation scheme is brought forward. In addition, the optimal solution recording scheme is also invoked in case of being lost during cooling process. Simulation results illustrate that in comparison with Genetic Algorithm (GA) MUD in the same simulation conditions, without turbo processing and soft-information, SA MUD proposed in this paper performs better, approaching the performance of Maximum Likelihood (ML) MUD and imposes lower complexity
Multi-group frequency hopping OFDMA based on statistical multiplexing
No full textIn this paper, the multi-group frequency hopping OFDMA (MG-FH OFDMA) based on the statistical multiplexing is proposed for the downlink cellular system. Compared with the existed random frequency hopping OFDMA (RFH-OFDMA) system utilizing the statistical multiplexing, the proposed MG-FH OFDMA invokes the deterministic hopping pattern to reduce the number of subcarrier collisions. By dividing all users into different groups, the subcarriers are utilized sufficiently. Latin Square hopping pattern and user index updating scheme are applied to randomize the subcarrier collisions among users. The user capacity, defined as the maximum number of users served with a basic data-rate in a cell, is calculated with the consideration of intra-cell capacity and the other cell interference (OCI). Results show that the proposed MG-FH OFDMA achieves higher user capacity than that of the RFH-OFDMA
Utility greedy discrete bit loading for interference limited multi-cell OFDM system
No full textIn this contribution we present the solution of the utility greedy discrete bit loading for interference limited multicell OFDM networks. Setting the utility as the sum of consumed power proportions, the algorithm follows greedy way to achieve the maximum throughput of the system. Simulation has shown that the proposed algorithm has better performance and lower complexity than the traditional optimal algorithm. The discussion of the results is provided
Energy-Efficient Train Operation: Conclusions and Future Work
No full textThis chapter gives the basic conclusions about energy-efficient train operation covering energy-efficient train driving, energy-efficient train timetabling, regenerative braking, energy storage systems and power supply networks. Future work that will develop energy-efficient train operation further include the interaction of connected driver advisory systems (C-DAS) and automatic train operation (ATO) with railway traffic management systems, cooperative train control in platoons of virtually coupled trains, digital twin technology and particularly its application to power supply systems, and the interaction between the railway network with the electrical power grid and renewable energy generation.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Transport and Plannin
Relating Research and Teaching: comparing experiences and beliefs
No full textThe relationship between research and teaching has possible benefits and inherent tensions. It is a recurrent topic of discussion by faculty including engineering educators. Exploring a potentially beneficial relationship and is of interest and possible value to engineering faculty, our students, and our stakeholders. Institutions and departments have developed a range of approaches including research-led, research informed, or just plain scholarly. This paper examines the relationship between research and teaching in the undergraduate curriculum. It compares and contrasts evidence of the beliefs and experiences of the engineering faculty and the engineering student. It presents and analyses the result of surveys which gathered qualitative and qualitative data to explore the inter-relationship of research and teaching; in the curriculum; and as it is delivered and experienced in the lab, seminar room and lecture hall. This research builds on existing work developed in a preliminary study which examined ways in which synergies between research and teaching could be achieved, particularly in the ‘hard/applied’ areas of the curriculum. It analyses data from the ‘research-intensive’ and the ‘teaching-intensive’ perspective
Education for Cataloging in Spanish Universities: A Descriptive and Critical Study
No full textObjective: This is a critical descriptive study of the situation of cataloging as an academic discipline within Library and Information Science studies in Spain. Material and methods: The descriptive analysis of the sectional contents of the general and specific guidelines of the degrees of Diplomado (three-year degree) and Licenciado (fiveyear degree) in LIS and the curricular programs of the Spanish university schools or departments. Variables analyzed: The denomination and content descriptors of the course offerings and credit hours. The test-retest method was used, with a qualitative processing of data. Results: General data is given about the studies in LIS: their introduction, the universities that offer them, and the degrees awarded. Cataloging is considered an obligatory core subject matter, and is represented by several courses that present important differences insofar as their denominations, their credits, and their character from one curricular program to the next. The average credit requisite for obligatory courses in cataloging in Spain is 14 (1 credit = 10 class hours), and 19.7 if electives are also considered. At present, this discipline is undergoing a reform that will produce important changes as a result of the adaptation of university studies to the common framework of the European Union
Introduction to Energy-Efficient Train Operation
No full textRailway, as one of the most energy-efficient transport, plays an essential role in improving the world’s energy and environmental sustainability. Statistics about rail share of transport activities and the corresponding energy consumption will demonstrate the energy efficiency of railway and indicate the potential of developing railway transport. Therefore, this chapter will provide an overview of the railway's energy consumption and traffic volume shares. Statistics presented in this chapter show that railway energy consumption decreased in these decades while its transport volume kept stable, and the traffic volume share of the railway is extremely large in urban transport. To achieve the goal of carbon neutralization, the European Union and many countries have conducted research projects on railway energy conservation. The technologies developed in these projects include energy-efficient train driving, integrated timetabling, using regenerative braking energy, etc. A summary of these technologies is also given, along with their potential energy savings, which range from 1 to 25%. This book will analyse and illustrate the whole systems processes of train operation with optimisation solutions. The structure of the following chapters will be presented at the end.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Transport and Plannin
A Chinese lecturer in an English university: an unfinished journey
No full textThis chapter portraits a learning journey of an academic. The narrative chapter points a way forward to new modes of inter-cultural understanding of learners. The author of this chapter invites the readers to become fellow travellers to gain from his unique learning journeys an understanding of what is common to all learning. The chapter indicates that learning is often transformative, indeterminate and unfinished. The author invites readers to consider following questions: what do they tell us about learning itself? About what it means to be a learner in the first quarter of the 21st Century? What do we learn about the experience of learning
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