A Dichotomy Theorem for Circular Colouring Reconfiguration

The "reconfiguration problem" for circular colourings asks, given two $(p,q)$-colourings $f$ and $g$ of a graph $G$, is it possible to transform $f$ into $g$ by changing the colour of one vertex at a time such that every intermediate mapping is a $(p,q)$-colouring? We show that this problem can be solved in polynomial time for $2\leq p/q <4$ and is PSPACE-complete for $p/q\geq 4$. This generalizes a known dichotomy theorem for reconfiguring classical graph colourings.Comment: 22 pages, 5 figure

Stretching, embeddedness, and scripts in a sociotechnical transition: explaining the failure of electric mobility at Better Place (2007–2013)

Based on field research, interviews, and participant observation, this study explores the failure of Better Place—a now bankrupt company—to successfully demonstrate and deploy battery swapping stations and electric vehicle charging infrastructure. To do so, it draws from concepts in innovation studies, sociotechnical transitions, management science, organizational studies, and sociology. The study expands upon the notion of “fit-stretch”, which explains how innovations can move from an initial “fit” (with existing user practices, discourses, technical form) to a subsequent “stretch” (as the technology further develops, new functionalities are opened up, etc.) in the process of long-term transitions. It also draws from the “dialectical issue life cycle model” or “triple embeddedness framework” to explain the process whereby incumbent industry actors can introduce defensive innovations to “contain” a new niche from expanding. It lastly incorporates elements from design-driven innovation and organizational learning related to schemas and scripts, concepts that illustrate the vision-dependent and discursive elements of the innovation process. It uses the case study of Better Place to test and build upon these concepts. With a market valuation of more than $2 billion, Better Place was poised to become one of the most innovative companies in the electric mobility market. Yet after operating for five years it declared bankruptcy and saw its assets sold off for less than$500,000. We suggest here that Better Place failed because it “stretched” to the point that it “broke;” that it provoked a defensive response from both old automotive manufacturers (such as General Motors) and new ones (such as Tesla); and that the fantastic nature of its visionary scripts convinced its investors and promoters to unrealistically raise expectations and downplay persistent risks

Solitary wave propagation and steering through light-induced refractive potentials

The steering of a self-guided beam in a dye-doped nematic liquid crystal caused by an external illumination (control beam) that induces changes in the refractive index of the medium is theoretically analyzed. The interaction between the control beam and the dye molecules modifies the anchoring of the nematic molecules, so changing the director orientation in the bulk of the medium. Beam evolution is investigated by use of a modulation theory approach. It is found that the beam trajectory is independent of the beam profile, as long as this profile is self-similar. Solutions obtained from the modulation theory approach are in excellent agreement with numerical solutions

Facilitators and barriers to the successful implementation of pediatric antibacterial drug trials: Findings from CTTI's survey of investigators.

An urgent need exists to develop new antibacterial drugs for children. We conducted research with investigators of pediatric antibacterial drug trials to identify facilitators and barriers in the conduct of these trials. Seventy-three investigators completed an online survey assessing the importance of 15 facilitators (grouped in 5 topical categories) and the severity of 36 barriers (grouped in 6 topical categories) to implementing pediatric antibacterial drug trials. Analysis focused on the identification of key factors that facilitate the successful implementation of pediatric antibacterial drug trials and the key barriers to implementation. Almost all investigators identified two factors as very important facilitators: having site personnel for enrollment and having adequate funding. Other top factors were related to staffing. Among the barriers, factors related to parent concerns and consent were prominent, particularly obtaining parental consent when there was disagreement between parents, concerns about the number of blood draws, and concerns about the number of invasive procedures. Having overly narrow eligibility criteria was also identified as a major barrier. The survey findings suggest three areas in which to focus efforts to help facilitate ongoing drug development: (1) improving engagement with parents of children who may be eligible to enroll in a pediatric antibacterial drug trial, (2) broadening inclusion criteria to allow more participants to enroll, and (3) ensuring adequate staffing and establishing sustainable financial strategies, such as funding pediatric trial networks. The pediatric antibacterial drug trials enterprise is likely to benefit from focused efforts by all stakeholders to remove barriers and enhance facilitation

Navigating expert skepticism and consumer distrust: rethinking the barriers to vehicle-to-grid (V2G) in the Nordic region

Vehicle-to-grid (V2G) refers to a technology that could help make the electricity grid more effective, reduce the cost of ownership of electric vehicles (EVs), and help integrate intermittent renewable energy sources. However, despite these advantages, implementation and even knowledge of the technology is not widespread. In order to explore why, we ask the question: what are the barriers that V2G currently faces? To provide an answer, the authors conducted 227 semi-structured interviews with transportation and electricity experts from 201 institutions across seventeen cities within the a market currently experimenting with electric mobility and V2G, the Nordic region. Results show that there is an extensive range of barriers facing V2G, with experts suggesting in total 35 categories of barriers. While the literature espouses substantial benefits of V2G, the experts interviewed generally displayed skepticism of the benefits and necessity of V2G in the Nordics. We categorized the top nine discussed barriers into four clusters. These clusters focused on the experts’ skepticism of the benefits of V2G, consumer acceptance, economic viability, and regulatory structure for V2G participation. We conclude the paper with policy implications and suggestions for future research

The demographics of decarbonizing transport: the influence of gender, education, occupation, age, and household size on electric mobility preferences in the Nordic region

Many researchers, policymakers and other stakeholders have explored and supported efforts to transition towards more sustainable forms of low-carbon mobility. Often, discussion will flow from a narrow view of consumer perceptions surrounding passenger vehicles—presuming that they act in rationalist, instrumental, and predictable patterns. In this paper, we hold that a better understanding of the social and demographic perceptions of electric vehicles (compared to other forms of mobility, including conventional cars) is needed. We provide a comparative and mixed methods assessment of the demographics of electric mobility and stated preferences for electric vehicles, drawing primarily on a survey distributed to more than 5,000 respondents across Denmark, Finland, Iceland, Norway and Sweden. We examine how gender influences preferences; how experience in the form of education and occupation shape preferences; and how aging and household size impact preferences. In doing so we hope to reveal the more complex social dynamics behind how potential adopters consider and calculate various aspects of conventional mobility, electric mobility, and vehicle-to-grid systems. In particular, our results suggest that predominantly men, those with higher levels of education in full time employment, especially with occupations in civil society or academia, and below middle age (30 to 45), are the most likely to buy them. However, our analysis also reveals other market segments where electric vehicles may take root, e.g. among higher income females and retirees/pensioners. Moreover, few respondents were orientated towards V2G, independent of their demographic attributes. Our empirical results can inform ongoing discussions about energy and transport policy, the drivers of environmental change, and deliberations over sustainability transitions

Beyond emissions and economics: rethinking the co-benefits of Nordic Electric Vehicles (EVs) and Vehicle-To-Grid (V2G)

Electric vehicles and vehicle-to-grid are one option to achieve the transition to decarbonizing society. Despite perceived advantages of cost-savings and carbon reductions, such technologies have faced various barriers that has prevented wide-scale adoption. While much literature has carefully investigated the techno-economics dimensions to electric mobility, we ask: what are the full set of benefits that EVs and V2G offer? To provide an answer, the authors conducted 227 semi-structured interviews with transportation and electricity experts from over 200 institutions across the Nordic region. Results show that there is an extensive range of benefits for both EVs and V2G, with experts suggesting 29 and 25 categories of benefits for EVs and V2G, respectively. Though the experts covered the obvious benefits of economic savings, emissions, and renewable energy integration, several other novel benefits were identified. The second and third most common discussed EV benefit was noise reduction and better performance, which are typically not widely discussed. Similarly we find that V2G benefits covered topics like vehicle-to-home and solar integration, as well as more novel benefits, like vehicle-to-telescope and emergency power backup. The article concludes with a discussion of future research and benefits in the context of energy research and analysis