VCSEL-based, CWDM - PON systems using reflective technology for bi-directional multi-play service provision

Orthogonal frequency division multiplexing based on radio-overfiber schemes allows the direct use of multiple, native format wireless platforms. In combination with standard baseband provision such as Gigabit Ethernet, this provides access to a wide range of services without requiring specialized end-user equipment. However, such signals have a high laser power-bandwidth requirement which may not be a good fit to the domestic environment. Here we explore the use of low-power optical components in customer premises which interface with an intermediate optical network node. Two solutions in the context of SSMF over a CWDM optical network are described, based on either reflective or direct modulation. EVMs of better than 35 dB were achieved. ©2012 Optical Society of America

480Mbit/s UWB bi-directional radio over fiber CWDM PON using ultra-low cost and power VCSELs

Radio-over-fiber (RoF) schemes offer the possibility of permitting direct access to native format services for the domestic user. A low power requirement and cost effectiveness are crucial to both the service provider and the end user. Here, we present an ultra-low cost and power RoF scheme using direct modulation of commercially-available 1344 nm and 1547 nm VCSELs by band-group 1 UWB wireless signals (ECMA-368) at near broadcast power levels. As a result, greatly simplified electrical-optical-electrical conversion is accomplished. A successful demonstration over a transmission distance of 20.1 km is described using a SSMF, CWDM optical network. EVMs of better than-18.3 dB were achieved. © 2011 Optical Society of America

Certainty of meeting fertility intentions declines in Europe during the 'Great Recession'

Relatively little research has been conducted on how economic recessions impact fertility intentions. In particular, uncertainty in reproductive intentions has not been examined in relation to economic shocks. The purpose of this paper is to estimate the impact of individuals' perception of negative changes in both their own and their country's economic performance on reproductive intentions in Europe during the time of the 'Great Recession' (2006-2011). Crucially, we examine both intentions and stated certainty of meeting these intentions. Using the 2011 Eurobarometer survey for 27 European countries, fertility intentions and reproductive uncertainty are regressed on individuals' perceptions of past trends in country's economic situation, household's financial situation, and personal job situation. Multilevel ordinal regressions models are run separately for people at parities zero and one as well as controlling for a set of socio-demographic variables. A worsening in the households' financial situation, as perceived in the years of the economic crisis, does not affect people's fertility intentions but rather the certainty of meeting these intentions. This relationship holds true at the individual-level for childless people. The more negative the individual's assessment of the household's financial situation, the higher the reproductive uncertainty. While this works exclusively at the country-level for people at parity one, the higher the share of people's pessimism on households' financial situation in the country the more insecure individuals of such a country are about having additional children. The empirical evidence suggests that individuals' uncertainty about realising their fertility intentions has risen in Europe and is positively linked to people's perceived household financial difficulties. If European economies continue to fare poorly, fertility intentions could eventually start to decline in response to such difficulties. (authors' abstract

Dual-drive LiNbO_3 interferometric Mach-Zehnder architecture with extended linear regime for high peak-to-average OFDM-based communication systems

A dual-drive LiNbO3 architecture modulator with chirp management is proposed and developed offering SFDR > 25 dB in a 1.4 V bias excursion compared to only 0.5 V bias excursion in a conventional Mach-Zehnder electro-optical modulator (MZ-EOM). The architecture effectively extends the linear regime and enables the optical transmission of wireless systems employing orthogonal division multiplexing (OFDM) modulation such as ultra-wide band (UWB) which require high linearity over a broad frequency range due to their high peak-to-average power ratio (PARP). Radio-over-fiber UWB transmission in a passive optical network is experimentally demonstrated employing this technique, exhibiting an enhancement of 2.2 dB in EVM after 57 km SSMF when the dual-drive developed modulator is employed. © 2011 Optical Society of America

Linked lives: the utility of an agent-based approach to modelling partnership and household formation in the context of social care

The UK’s population is aging, which presents a challenge as older people are the primary users of health and social care services. We present an agent-based model of the basic demographic processes that impinge on the supply of, and demand for, social care: namely mortality, fertility, health-status transitions, internal migration, and the formation and dissolution of partnerships and households. Agent-based modeling is used to capture the idea of “linked lives” and thus to represent hypotheses that are impossible to express in alternative formalisms. Simulation runs suggest that the per-taxpayer cost of state-funded social care could double over the next forty years. A key benefit of the approach is that we can treat the average cost of state-funded care as an outcome variable, and examine the projected effect of different sets of assumptions about the relevant social processes

Executive remuneration consultancy in the UK: exploring a professional project through the lens of institutional work

This article responds to recent calls to examine the development of professionalism through the lens of institutional theory. We investigate the development of the new professional service of executive remuneration consultancy (ERC) in the UK through the lens of institutional work. Specifically, drawing upon Lawrence and Suddaby (2006) and Suddaby and Viale (2011), we explore the relationship between macro-scale occupational/organizational and micro-scale individual-level dynamics of the ERC professional project and situate its development in relation to the broader field of executive remuneration practices. We show that the institutional work of creating the new professional project is contested and that the ERC development may be better understood as part of broader efforts to create and maintain the institution of executive pay-setting practices. We argue that the institutional work lens has the potential to produce a more nuanced understanding of the internal dynamics of the ERC professionalization process and its role in reconfiguring broader institutional arrangements. By exploring the analytical purchase of the concept of institutional work, the article contributes to the emerging body of empirical evidence outlining the potential of (neo-) institutional approaches to offer a more productive understanding of contemporary professionalis

Microservices and serverless functions – lifecycle, performance, and resource utilisation of edge based real-time IoT analytics

Edge Computing harnesses resources close to the data sources to reduce end-to-end latency and allow real-time process automation for verticals such as Smart City, Healthcare and Industry 4.0. Edge resources are limited when compared to traditional Cloud data centres; hence the choice of proper resource management strategies in this context becomes paramount. Microservice and Function as a Service architectures support modular and agile patterns, compared to a monolithic design, through lightweight containerisation, continuous integration / deployment and scaling. The advantages brought about by these technologies may initially seem obvious, but we argue that their usage at the Edge deserves a more in-depth evaluation. By analysing both the software development and deployment lifecycle, along with performance and resource utilisation, this paper explores microservices and two alternative types of serverless functions to build edge real-time IoT analytics. In the experiments comparing these technologies, microservices generally exhibit slightly better end-to-end processing latency and resource utilisation than serverless functions. One of the serverless functions and the microservices excel at handling larger data streams with auto-scaling. Whilst serverless functions natively offer this feature, the choice of container orchestration framework may determine its availability for microservices. The other serverless function, while supporting a simpler lifecycle, is more suitable for low-invocation scenarios and faces challenges with parallel requests and inherent overhead, making it less suitable for real-time processing in demanding IoT settings