Understanding Consumer Behaviour to Reduce Environmental Impacts through Sustainable Product Design

The use phase of the lifecycle of electrical products has a significant environmental impact, mainly determined by the consumer’s behaviour. Many consumers do not make the link between their daily consumption behaviour in the household and environmental problems such as climate change. In the 21st century, the residential sector, together with transport and industry, is one of the largest man-made contributors in the UK to climate change. It is argued that technological innovations, current eco-efficient products and consumer education have been ineffective in creating the long term radical behavioural change needed to reduce the impact of product use. Products, as the interface between consumers and consumption activities, have the potential to influence the way in which consumption occurs. In the sustainable design field however, designer responsibility traditionally considers raw material selection and product disposal. There is limited work that addresses the environmental impacts relating directly to use behaviour of the product. This paper illustrates that user behaviour studies can be the preliminary step for designers to improve energy efficiency of products. A single product type, household cold appliance, was chosen as a case to explore the capacity of designer-conducted user study to identify unsustainable aspects of product use. Adopting a user-centred approach, two pilot studies were used to gain an insight into domestic fridge and freezer use in the UK. Qualitative ethnographical research methods were employed to investigate the daily practices and “real” needs of user as well as the connection between the knowledge, attitudes, intention and actual action. The design suggestions drawn from the user behaviour analysis provide examples of how energy impact level of the interaction with the product can be reduced through design. Keywords: User-Centred Research; Sustainable Product Design; Changing Consumer Behaviour; Design Research; Household Energy Consumption; Household Cold Appliance.</p

Influence Maximization Meets Efficiency and Effectiveness: A Hop-Based Approach

Influence Maximization is an extensively-studied problem that targets at selecting a set of initial seed nodes in the Online Social Networks (OSNs) to spread the influence as widely as possible. However, it remains an open challenge to design fast and accurate algorithms to find solutions in large-scale OSNs. Prior Monte-Carlo-simulation-based methods are slow and not scalable, while other heuristic algorithms do not have any theoretical guarantee and they have been shown to produce poor solutions for quite some cases. In this paper, we propose hop-based algorithms that can easily scale to millions of nodes and billions of edges. Unlike previous heuristics, our proposed hop-based approaches can provide certain theoretical guarantees. Experimental evaluations with real OSN datasets demonstrate the efficiency and effectiveness of our algorithms.Comment: Extended version of the conference paper at ASONAM 2017, 11 page

Nonadiabatic quantum pumping in mesoscopic nanostructures

We consider a nonadiabatic quantum pumping phenomena in a ballistic narrow constriction. The pumping is induced by a potential that has both spatial and temporal periodicity characterized by $K$ and $\Omega$. In the zero frequency ($\Omega=0$) limit, the transmission through narrow constriction exhibits valley structures due to the opening up of energy gaps in the pumping region -- a consequence of the $K$ periodicity. These valley structures remain robust in the regime of finite $\Omega$, while their energies of occurrence are shifted by about $\hbar\Omega/2$. The direction of these energy shifts depend on the directions of both the phase-velocity of the pumping potential and the transmitting electrons. This frequency dependent feature of the valley structures gives rise to both the asymmetry in the transmission coefficients and the pumping current. An experimental setup is suggested for a possible observation of our nonadiabatic quantum pumping findings.Comment: 4 pages, 2 figure

Gamma-ray emission from middle-aged supernova remnants interacting with molecular clouds: the challenge for current models

We compare the $\gamma$-ray spectra from 10 middle-aged supernova remnants (SNRs), which are interacting with molecular clouds (MCs), with the model prediction from widely used escaping scenario and direct interaction scenario. It is found that the $\gamma$-ray data is inconsistent with the escaping scenario statistically, as it predicts a diversity of spectral shape which is not observed. The inconsistency suggests that the free escape boundary adopted in the escaping model is not a good approximation, which challenges our understanding of cosmic ray (CR) escaping in SNRs. In addition, we show that ambient CRs is potentially important for the $\gamma$-ray emission of illuminated MCs external to W28 and W44. In direct interaction scenario, the model involving re-acceleration of pre-existing CRs and adiabatic compression is able to explain the emission from most SNRs. The dispersion shown in the TeV data is naturally explained by different acceleration time of CR particles in SNRs. Re-acceleration of pre-existing CRs suggests a transition of seed particles, which is from thermal injected seed particle in young SNRs to ambient CRs in old SNRs. The transition needs to be tested by future multi-wavelength observation. In the end, we propose that radiative SNR without MC interaction is also able to produce a significant amount of $\gamma$-ray emission. A good candidate is S147. With accumulated Fermi data and CTA in future we expect to detect more remnants like S147.Comment: 15 pages and 7 figures. Accepted by MNRA