Modal coupling in linear control systems using robust eigenstructure assignment

Eigenvalue assignment methods are used widely in the design of control and state-estimation systems. The corresponding eigenvectors can be selected to ensure robustness. For specific applications, eigenstructure assignment can also be applied to achieve more general performance criteria. In this paper a new output feedback design approach using robust eigenstructure assignment to achieve prescribed mode input and output coupling is described. A minimisation technique is developed to improve both the mode coupling and the robustness of the system, whilst allowing the precision of the eigenvalue placement to be relaxed. An application to the design of an automatic flight control system is demonstrated.

Social and environmental report assurance: some interview evidence

The steady growth of social and environmental reporting (SER) is being accompanied by an increase in social and environmental reporting assurance (SERA). The existing literature on SERA suggests that it is necessary to build credibility and trust among corporate stakeholders. Prior work has also found evidence of managerial and professional capture of SERA. In this paper, we present empirical evidence from interviews with corporate social responsibility representatives from 20 UK listed companies on whether they consider SERA to be necessary. We believe this to be the first research into SERA that uses an interview method. Our interviews revealed mixed feelings. Half of the respondents believed that external SERA would enhance credibility and trust which confirmed the prior literature. However, the other half believed that external SERA was not necessary, believing that internal assurance was sufficient. This was because they saw SERA as predominantly a managerial tool, useful for checking the efficiency of internal management control systems, rather than as a mechanism for enhancing corporate accountability to stakeholders and building credibility and trust. The potential for SERA to be a mechanism whereby greater dialogue is created between companies and their stakeholders on social and environmental issues is not being harnessed. This paper thus demonstrates a fundamental difference between the external prior normative literature and the managerial motivation in the SERA area.

Stakeholder inclusivity in social and environmental report assurance

Purpose – The purpose of the research was to discover the process of social and environmental report assurance (SERA) and thereby evaluate the benefits, extent of stakeholder inclusivity and/or managerial capture of SERA processes and the dynamics of SERA as it matures. Design/methodology/approach – This paper used semi-structured interviews with 20 accountant and consultant assurors to derive data, which were then coded and analysed, resulting in the identification of four themes. Findings – This paper provides interview evidence on the process of SERA, suggesting that, although there is still managerial capture of SERA, stakeholders are being increasingly included in the process as it matures. SERA is beginning to provide dual-pronged benefits, adding value to management and stakeholders simultaneously. Through the lens of Freirian dialogic theory, it is found that SERA is starting to display some characteristics of a dialogical process, being stakeholder inclusive, demythologising and transformative, with assurors perceiving themselves as a “voice” for stakeholders. Consequently, SERA is becoming an important mechanism for driving forward more stakeholder-inclusive SER, with the SERA process beginning to transform attitudes of management towards their stakeholders through more stakeholder-led SER. However, there remain significant obstacles to dialogic SERA. The paper suggests these could be removed through educative and transformative processes driven by assurors. Originality/value – Previous work on SERA has involved predominantly content-based analysis on assurance statements. However, this paper investigates the details of the SERA process, for the first time using qualitative interview data.

Impact of the modal aerosol scheme GLOMAP-mode on aerosol forcing in the Hadley Centre Global Environmental Model

The Hadley Centre Global Environmental Model (HadGEM) includes two aerosol schemes: the Coupled Large-scale Aerosol Simulator for Studies in Climate (CLASSIC), and the new Global Model of Aerosol Processes (GLOMAP-mode). GLOMAP-mode is a modal aerosol microphysics scheme that simulates not only aerosol mass but also aerosol number, represents internally-mixed particles, and includes aerosol microphysical processes such as nucleation. In this study, both schemes provide hindcast simulations of natural and anthropogenic aerosol species for the period 2000–2006. HadGEM simulations of the aerosol optical depth using GLOMAP-mode compare better than CLASSIC against a data-assimilated aerosol re-analysis and aerosol ground-based observations. Because of differences in wet deposition rates, GLOMAP-mode sulphate aerosol residence time is two days longer than CLASSIC sulphate aerosols, whereas black carbon residence time is much shorter. As a result, CLASSIC underestimates aerosol optical depths in continental regions of the Northern Hemisphere and likely overestimates absorption in remote regions. Aerosol direct and first indirect radiative forcings are computed from simulations of aerosols with emissions for the year 1850 and 2000. In 1850, GLOMAP-mode predicts lower aerosol optical depths and higher cloud droplet number concentrations than CLASSIC. Consequently, simulated clouds are much less susceptible to natural and anthropogenic aerosol changes when the microphysical scheme is used. In particular, the response of cloud condensation nuclei to an increase in dimethyl sulphide emissions becomes a factor of four smaller. The combined effect of different 1850 baselines, residence times, and abilities to affect cloud droplet number, leads to substantial differences in the aerosol forcings simulated by the two schemes. GLOMAP-mode finds a presentday direct aerosol forcing of −0.49Wm−2 on a global average, 72% stronger than the corresponding forcing from CLASSIC. This difference is compensated by changes in first indirect aerosol forcing: the forcing of −1.17Wm−2 obtained with GLOMAP-mode is 20% weaker than with CLASSIC. Results suggest that mass-based schemes such as CLASSIC lack the necessary sophistication to provide realistic input to aerosol-cloud interaction schemes. Furthermore, the importance of the 1850 baseline highlights how model skill in predicting present-day aerosol does not guarantee reliable forcing estimates. Those findings suggest that the more complex representation of aerosol processes in microphysical schemes improves the fidelity of simulated aerosol forcings.

An industry viewpoint on the role of farm assurance in delivering food safety to the consumer: the case of the dairy sector in England and Wales

Food safety, alongside food quality, remains a primary concern of both consumers and those along the whole food supply chain, leading to regulation by government alongside private third party certification. Much has been written about the value of these systems primarily from the perception of the consumer. This paper reports on a study that examined industry perceptions on the regulatory and assurance systems within the dairy sector of England and Wales. It found that the primary producer found value in both systems, although from a food hygiene focus regulation was seen to be more rigorous. Other stakeholders along the dairy food supply chain saw the assurance scheme as more rigorous. All stakeholders recognised the need to reduce duplication in delivering food safety through combining key elements of both systems with the added potential for better communication of both food safety and quality to the final consumer.

N1 enhancement in synesthesia during visual and audio-visual perception in semantic cross-modal conflict situations: an ERP study

Synesthesia entails a special kind of sensory perception, where stimulation in one sensory modality leads to an internally generated perceptual experience of another, not stimulated sensory modality. This phenomenon can be viewed as an abnormal multisensory integration process as here the synesthetic percept is aberrantly fused with the stimulated modality. Indeed, recent synesthesia research has focused on multimodal processing even outside of the specific synesthesia-inducing context and has revealed changed multimodal integration, thus suggesting perceptual alterations at a global level. Here, we focused on audio-visual processing in synesthesia using a semantic classification task in combination with visually or auditory-visually presented animated and in animated objects in an audio-visual congruent and incongruent manner. Fourteen subjects with auditory-visual and/or grapheme-color synesthesia and 14 control subjects participated in the experiment. During presentation of the stimuli, event-related potentials were recorded from 32 electrodes. The analysis of reaction times and error rates revealed no group differences with best performance for audio-visually congruent stimulation indicating the well-known multimodal facilitation effect. We found enhanced amplitude of the N1 component over occipital electrode sites for synesthetes compared to controls. The differences occurred irrespective of the experimental condition and therefore suggest a global influence on early sensory processing in synesthetes.

The adoption of the materiality concept in social and environmental reporting assurance: a field study approach

This study investigates the logics or values that shape the social and environmental reporting (SER) and SER assurance (SERA) process. The influence of logics is observed through a study of the conceptualisation and operationalisation of the materiality concept by accounting and non-accounting assurors and their assurance statements. We gathered qualitative data from interviews with both accounting and non-accounting assurors. We analysed the interplay between old and new logics that are shaping materiality as a reporting concept in SER. SER is a rich field in which to study the dynamics of change because it is a voluntary, unregulated, qualitative reporting arena. It has a broad, stakeholder audience, where accounting and non-accounting organisations are in competition. There are three key findings. First, the introduction of a new, stakeholder logic has significantly changed the meaning and role of materiality. Second, a more versatile, performative, social understanding of materiality was portrayed by assurors, with a forward-looking rather than a historic focus. Third, competing logics have encouraged different beliefs about materiality, and practices, to develop. This influenced the way assurors theorised the concept and interpreted outcomes. A patchwork of localised understandings of materiality is developing. Policy implications both in SERA and also in financial audit are explored.

Situation assessment through multi-modal sensing of dynamic environments to support cognitive robot control

Awareness of emerging situations in a dynamic operational environment of a robotic assistive device is an essential capability of such a cognitive system, based on its effective and efficient assessment of the prevailing situation. This allows the system to interact with the environment in a sensible (semi)autonomous / pro-active manner without the need for frequent interventions from a supervisor. In this paper, we report a novel generic Situation Assessment Architecture for robotic systems directly assisting humans as developed in the CORBYS project. This paper presents the overall architecture for situation assessment and its application in proof-of-concept Demonstrators as developed and validated within the CORBYS project. These include a robotic human follower and a mobile gait rehabilitation robotic system. We present an overview of the structure and functionality of the Situation Assessment Architecture for robotic systems with results and observations as collected from initial validation on the two CORBYS Demonstrators.

On translational superfluidity and the Landau criterion for Bose gases in the Gross-Pitaevski limit

The two-fluid and Landau criteria for superfluidity are compared for trapped Bose gases. While the two-fluid criterion predicts translational superfluidity, it is suggested, on the basis of the homogeneous Gross-Pitaevski limit, that a necessary part of Landau`s criterion, adequate for non-translationally invariant systems, does not hold for trapped Bose gases in the GP limit. As a consequence, if the compressibility is detected to be very large (infinite by experimental standards), the two-fluid criterion is seen to be the relevant one in case the system is a translational superfluid, while the Landau criterion is the relevant one if translational superfluidity is absent.