A survey on OFDM-based elastic core optical networking

Orthogonal frequency-division multiplexing (OFDM) is a modulation technology that has been widely adopted in many new and emerging broadband wireless and wireline communication systems. Due to its capability to transmit a high-speed data stream using multiple spectral-overlapped lower-speed subcarriers, OFDM technology offers superior advantages of high spectrum efficiency, robustness against inter-carrier and inter-symbol interference, adaptability to server channel conditions, etc. In recent years, there have been intensive studies on optical OFDM (O-OFDM) transmission technologies, and it is considered a promising technology for future ultra-high-speed optical transmission. Based on O-OFDM technology, a novel elastic optical network architecture with immense flexibility and scalability in spectrum allocation and data rate accommodation could be built to support diverse services and the rapid growth of Internet traffic in the future. In this paper, we present a comprehensive survey on OFDM-based elastic optical network technologies, including basic principles of OFDM, O-OFDM technologies, the architectures of OFDM-based elastic core optical networks, and related key enabling technologies. The main advantages and issues of OFDM-based elastic core optical networks that are under research are also discussed

Software defined networking: meeting carrier grade requirements

Software Defined Networking is a networking paradigm which allows network operators to manage networking elements using software running on an external server. This is accomplished by a split in the architecture between the forwarding element and the control element. Two technologies which allow this split for packet networks are ForCES and Openflow. We present energy efficiency and resilience aspects of carrier grade networks which can be met by Openflow. We implement flow restoration and run extensive experiments in an emulated carrier grade network. We show that Openflow can restore traffic quite fast, but its dependency on a centralized controller means that it will be hard to achieve 50 ms restoration in large networks serving many flows. In order to achieve 50 ms recovery, protection will be required in carrier grade networks

What about me? Factors affecting individual adaptive coping capacity across different populations

 When and why will people adapt to climate change? We conducted a number of studies examining the psychological drivers of individual adaptation to climate change across different populations. We used a variety of methodologies including interviews, surveys, survey experiments and face-to-face experiments. There was a high level of rigour involved in each of these methodologies which means that we can believe in the results. This programme of research represents one of the largest and most integrated attempts to understand some of the psychological drivers of individual-level adaptation.First, we used the most recent advances in the psychological literature of coping more generally to develop a valid scale to measure coping with climate change. Across three studies we found that our tool was both reliable and valid, providing an accurate measure of the different ways in which people cope with climate change. This tool can now be used to understand the effects of both adaptive and maladaptive coping and to understand what leads to these different ways of coping.Next, we examined adaptive capacity. We found that adaptive coping strategies were associated with perceiving climate change as a threat to oneself and one’s way of life, rating environmental goals as important, and believing that adaptive behaviours could help achieve significant personal goals. Furthermore, when looking at societal adaptive capacity (support for governmental policies) we found that not only were a threat appraisal, climate change or environmental goal, and goal connectedness related to support, but also political affiliation, perceived human contribution to climate change, (lack of) denying that climate change exists, and a number of emotions (enthusiasm, worry, (lack of) happiness, and (lack of ) embarrassment). By knowing these factors that lead to adaptive coping and support for adaptive policies we can identify strategies to improve individual adaptive capacity.Third, based on a range of psychological literature, we hypothesised that adaptive behaviour would be related to goals, goal connectedness, adaptive coping, beliefs about climate change (including denial), and emotions that create an uneasy state of activation (enthusiasm and hope combined with worry). We found support for each of these relationships. Thus, we can again identify strategies to increase adaptive climate change behaviour. Across the studies, we found that adaptive capacity and adaptive behaviours relied upon both “green” beliefs and goals and “non-green” beliefs and goals. Moreover, believing that the adaptive behaviours helped a person to achieve their goals (whether they were related to climate change or not) was strongly related to adaptive capacity and behaviour. We have therefore shown that we can improve adaptation not only in those people who want to help the environment but also in those who are less interested.Unfortunately, the goal structure of environmental goals appears difficult to change. However, making people think about politics did have an effect: Regardless of their own political orientation, a person’s belief about the degree of human contribution to climate change decreased when they were thinking about politics (compared to not thinking about politics). This has implications for how climate change adaptation is discussed in the media and by researchers.The results of our research also have implications for the communication of climate change adaptation policies. Our results show that framing the costs of reducing CO2 emissions in terms of a decrease in future gain—rather than as an opportunity-cost—renders people more willing to commit to climate change initiatives.In summary, this programme of research has taken an integrated and rigorous step towards greater understanding of some of the psychological drivers of individual adaptation to climate change. Given the complexity of the problem, more research is needed, however we believe that our research provides a good early step in this direction.Please cite as: Unsworth, K, Russell, S, Lewandowsky, S, Lawrence, C, Fielding, K, Heath, J, Evans, A, Hurlstone, M, & McNeill, I 2013 What about me? Factors affecting individual adaptive coping capacity across different populations, National Climate Change Adaptation Research Facility, Gold Coast, pp. 161. AbstractWhen and why will people adapt to climate change? We conducted a number of studies examining the psychological drivers of individual adaptation to climate change across different populations. We used a variety of methodologies including interviews, surveys, survey experiments and face-to-face experiments. There was a high level of rigour involved in each of these methodologies which means that we can believe in the results. This programme of research represents one of the largest and most integrated attempts to understand some of the psychological drivers of individual-level adaptation.First, we used the most recent advances in the psychological literature of coping more generally to develop a valid scale to measure coping with climate change. Across three studies we found that our tool was both reliable and valid, providing an accurate measure of the different ways in which people cope with climate change. This tool can now be used to understand the effects of both adaptive and maladaptive coping and to understand what leads to these different ways of coping.Next, we examined adaptive capacity. We found that adaptive coping strategies were associated with perceiving climate change as a threat to oneself and one’s way of life, rating environmental goals as important, and believing that adaptive behaviours could help achieve significant personal goals. Furthermore, when looking at societal adaptive capacity (support for governmental policies) we found that not only were a threat appraisal, climate change or environmental goal, and goal connectedness related to support, but also political affiliation, perceived human contribution to climate change, (lack of) denying that climate change exists, and a number of emotions (enthusiasm, worry, (lack of) happiness, and (lack of ) embarrassment). By knowing these factors that lead to adaptive coping and support for adaptive policies we can identify strategies to improve individual adaptive capacity.Third, based on a range of psychological literature, we hypothesised that adaptive behaviour would be related to goals, goal connectedness, adaptive coping, beliefs about climate change (including denial), and emotions that create an uneasy state of activation (enthusiasm and hope combined with worry). We found support for each of these relationships. Thus, we can again identify strategies to increase adaptive climate change behaviour. Across the studies, we found that adaptive capacity and adaptive behaviours relied upon both “green” beliefs and goals and “non-green” beliefs and goals. Moreover, believing that the adaptive behaviours helped a person to achieve their goals (whether they were related to climate change or not) was strongly related to adaptive capacity and behaviour. We have therefore shown that we can improve adaptation not only in those people who want to help the environment but also in those who are less interested.Unfortunately, the goal structure of environmental goals appears difficult to change. However, making people think about politics did have an effect: Regardless of their own political orientation, a person’s belief about the degree of human contribution to climate change decreased when they were thinking about politics (compared to not thinking about politics). This has implications for how climate change adaptation is discussed in the media and by researchers.The results of our research also have implications for the communication of climate change adaptation policies. Our results show that framing the costs of reducing CO2 emissions in terms of a decrease in future gain—rather than as an opportunity-cost—renders people more willing to commit to climate change initiatives.In summary, this programme of research has taken an integrated and rigorous step towards greater understanding of some of the psychological drivers of individual adaptation to climate change. Given the complexity of the problem, more research is needed, however we believe that our research provides a good early step in this direction

Semi-persistent RRC protocol for machine-type communication devices in LTE networks

In this paper, we investigate the design of a radio resource control (RRC) protocol in the framework of long-term evolution (LTE) of the 3rd Generation Partnership Project regarding provision of low cost/complexity and low energy consumption machine-type communication (MTC), which is an enabling technology for the emerging paradigm of the Internet of Things. Due to the nature and envisaged battery-operated long-life operation of MTC devices without human intervention, energy efficiency becomes extremely important. This paper elaborates the state-of-the-art approaches toward addressing the challenge in relation to the low energy consumption operation of MTC devices, and proposes a novel RRC protocol design, namely, semi-persistent RRC state transition (SPRST), where the RRC state transition is no longer triggered by incoming traffic but depends on pre-determined parameters based on the traffic pattern obtained by exploiting the network memory. The proposed RRC protocol can easily co-exist with the legacy RRC protocol in the LTE. The design criterion of SPRST is derived and the signalling procedure is investigated accordingly. Based upon the simulation results, it is shown that the SPRST significantly reduces both the energy consumption and the signalling overhead while at the same time guarantees the quality of service requirements

Report on the Information Retrieval Festival (IRFest2017)

The Information Retrieval Festival took place in April 2017 in Glasgow. The focus of the workshop was to bring together IR researchers from the various Scottish universities and beyond in order to facilitate more awareness, increased interaction and reflection on the status of the field and its future. The program included an industry session, research talks, demos and posters as well as two keynotes. The first keynote was delivered by Prof. Jaana Kekalenien, who provided a historical, critical reflection of realism in Interactive Information Retrieval Experimentation, while the second keynote was delivered by Prof. Maarten de Rijke, who argued for more Artificial Intelligence usage in IR solutions and deployments. The workshop was followed by a "Tour de Scotland" where delegates were taken from Glasgow to Aberdeen for the European Conference in Information Retrieval (ECIR 2017

Visible Light Communications towards 5G

5G networks have to offer extremely high capacity for novel streaming applications. One of the most promising approaches is to embed large numbers of co-operating small cells into the macro-cell coverage area. Alternatively, optical wireless based technologies can be adopted as an alternative physical layer offering higher data rates. Visible light communications (VLC) is an emerging technology for future high capacity communication links (it has been accepted to 5GPP) in the visible range of the electromagnetic spectrum (~370–780 nm) utilizing light-emitting diodes (LEDs) simultaneously provide data transmission and room illumination. A major challenge in VLC is the LED modulation bandwidths, which are limited to a few MHz. However, myriad gigabit speed transmission links have already been demonstrated. Non line-of-sight (NLOS) optical wireless is resistant to blocking by people and obstacles and is capable of adapting its’ throughput according to the current channel state information. Concurrently, organic polymer LEDs (PLEDs) have become the focus of enormous attention for solid-state lighting applications due to their advantages over conventional white LEDs such as ultra-low costs, low heating temperature, mechanical flexibility and large photoactive areas when produced with wet processing methods. This paper discusses development of such VLC links with a view to implementing ubiquitous broadcasting networks featuring advanced modulation formats such as orthogonal frequency division multiplexing (OFDM) or carrier-less amplitude and phase modulation (CAP) in conjunction with equalization techniques. Finally, this paper will also summarize the results of the European project ICT COST IC1101 OPTICWISE (Optical Wireless Communications - An Emerging Technology) dealing VLC and OLEDs towards 5G networks

Industry/government seminar on Large Space systems technology: Executive summary

The critical technology developments which the participating experts recommend as being required to support the early generation large space systems envisioned as space missions during the years 1985-2000 are summarized

Contending European agendas for agricultural innovation

Amid expectations for a European ‘transition to sustainable agriculture’, there are competing transitional processes. Given the widely acknowledged harm from agro-industrial systems, ‘unsustainable agriculture’ has divergent diagnoses and innovative solutions. This rivalry can be analysed as contending innovation agendas; the analysis here combines theoretical paradigms of agricultural innovation. In an EU policy context of a Knowledge-Based Bio-Economy (KBBE), there are divergent accounts of its key terms: biological resources, economy, relevant knowledge and knowledge-producers. Likewise, divergent accounts are found of innovation, intensification, resource efficiency, resilience, bio-energy, horizontal integration, etc. These divergent agendas are promoted by distinct stakeholder networks. The dominant agenda favours laboratory-based techno-scientific innovation as a source of ‘efficient’ inputs, which can use renewable resources more efficiently for competitive advantage in global value chains. By contrast, other agendas promote farmers’ knowledge of natural resources, especially via agro-ecological methods which can reduce energy inputs, increase productivity and add value through quality. With those contending agendas, rival stakeholder networks seek to influence R&D priorities. From the standpoint of multifunctional agriculture, such contending agendas can play complementary roles in different rural spaces. Some agro-food practices may combine aspects of different paradigms. As a concept, Agricultural Knowledge Systems may provide a common space for interchanges between divergent agendas and their research priorities. However, these innovation agendas promote conflicting visions of the future