Search results

Besse first conjectured that the solution of the critical point equation (CPE) must be Einstein. The CPE conjecture on some other types of Riemannian manifolds, for instance, odd-dimensional Riemannian manifolds has considered by many geometers. Hence, it deserves special attention to consider the CPE on a certain class of almost contact metric manifolds. In this direction, the authors considered CPE on almost f-cosymplectic manifolds.

The paper opted the tensor calculus on manifolds to find the solution of the CPE.

In this paper, in particular, the authors obtained that a connected f-cosymplectic manifold satisfying CPE with \lambda=\tilde{f} is Einstein. Next, the authors find that a three dimensional almost f-cosymplectic manifold satisfying the CPE is either Einstein or its scalar curvature vanishes identically if its Ricci tensor is pseudo anti‐commuting.

The paper proved that the CPE conjecture is true for almost f-cosymplectic manifolds.

Daily commuting trips of higher education (HE) students account for a large proportion of the carbon footprint of a HE institution. Considerations of students underlying their choice of travel mode and their decision to make the trip to campus or to study online are explored as a necessary first step for finding an optimal balance between online and on-campus learning from both a sustainability and an educational perspective.

Focus group conversations were held with student groups from different study programmes of a university of applied sciences in the Netherlands.

Dutch students’ travel mode choices seem to depend on measures regulating travel demand such as a free public transport card and high parking costs. The findings indicate that students make reasoned choices about making a trip to campus. These choices depend on considerations about their schedule, type, lecturer and content of a course, social norms and their own perceived behavioural control. Alternative online options can provide students with more flexibility to make choices adapted to their needs.

While these findings are useful for sustainable and educational reasons, they also seem helpful in times of COVID-19 which calls for a re-design of curricula to allow for blended forms of online and on-campus learning.

To the best of the authors’ knowledge, this paper is one of the first studies looking at students’ considerations when deciding whether to travel to campus to learn or stay at home learning online.

Recent studies on commuter parking in an age of fully autonomous vehicles (FAVs) suggest, that the number of parking spaces close to the workplace demanded by commuters will decline because of the capability of FAVs to return home, to seek out (free) parking elsewhere or just cruise. This would be good news because, as of today, parking is one of the largest consumers of urban land and is associated with substantial costs to society. None of the studies, however, is concerned with the special case of employer-provided parking, although workplace parking is a widespread phenomenon and, in many instances, the dominant form of commuter parking. The purpose of this paper is to analyze whether commuter parking will decline with the advent of self-driving cars when parking is provided by the employer.

This study looks at commuter parking from the perspective of both the employer and the employee because in the case of employer-provided parking, the firm’s decision to offer a parking space and the incentive of employees to accept that offer are closely interrelated because of the fringe benefit character of workplace parking. This study develops an economic equilibrium model that explicitly maps the employer–employee relationship, considering the treatment of parking provision and parking policy in the income tax code and accounting for adverse effects from commuting, parking and public transit. This study determines the market level of employer-provided parking in the absence and presence of FAVs and identifies the factors that drive the difference. This study then approximates the magnitude of each factor, relying on recent (first) empirical evidence on the impacts of FAVs.

This paper’s analysis suggests that as long as distortive (tax) policy favors employer-provided parking, FAVs are no guarantee to end up with less commuter parking.

This study’s findings imply that in a world of self-driving cars, policy intervention related to work commuting (e.g. fringe benefit taxation or transport pricing) might be even more warranted than today.

More and more work zone projects come with the needs of new construction and regular maintenance-related investments in transportation. Work zone projects can have many significant impacts socially, economically and environmentally. Minimizing the total impacts of work zone projects by optimizing relevant schedules is extremely important. This study aims to analyze the impacts of scheduling long-term work zone activities.

Optimal scheduling of the starting dates of each work zone project is determined by developing and solving using a bi-level genetic algorithm (GA)–based optimization model. The upper level sub-model is to minimize the total travel delay caused by work zone projects over the entire planning horizon, whereas the lower level sub-model is a traffic assignment problem under user equilibrium condition with elastic demand.

Sioux Falls network is used to develop and test the proposed GA-based model. The average and minimum total travel delays (TTDs) over generations of the proposed GA algorithm decrease very rapidly during the first 20 generations of the GA algorithm; after the 20th generations, the solutions gradually level off with a certain level of variations in the average TTD, showing the capability of the proposed method of solving the multiple work zone starting date optimization problem.

The proposed model can effectively identify the near-optimal solution to the long-term work zone scheduling problem with elastic demand. Sensitivity analysis of the impact of the elastic demand parameter is also conducted to show the importance of considering the impact of elastic demand parameter.

The implementation of project-based learning (PBL) activities in the curricula of engineering students has become a consolidated method to improve their skills. The purpose of this paper is to share the experience acquired by the authors from a decennial case-study on a student team PBL activity focused on design and development of human-powered vehicles (HPVs). A review of the project evolution, boundary constraints and management choices could provide inspiration and suggestions to faculty staff that would like to set-up similar experiences for engineering students in their universities.

A student team was funded by the authors in 2008 to gather engineering students interested in design and construction of HPVs. In the past decade, the team has grown from 10 up to 60 students enrolled per year and stimulated to develop a range of HPV designs for sports and mobility. The project management evolved as a consequence to com ply with the growing ambitions of the group and complexity of the goals.

A thorough analysis of factors contributing to the success of the project led to identification of the key factors to increase student participation: persistence of the faculty staff is essential, attending competitions and challenges increases students’ recruitment and formal recognition of the activity through credits and the implementation of intermediate assessment steps increase the active participation rate. Bigger teams reduce the negative impact of recruits eventually abandoning the project in an early stage. Ambitious goals keep students motivated for longer periods and enable a virtuous circle by transferring enthusiasm and knowledge to new members.

The activity is analyzed starting from a subjective experience perspective and some of the findings/conclusions may be not applicable in a different context. However, such review can suggest strategies on the long-term period to create similar conditions elsewhere.

In the last part of the paper, it is pointed out how PBL projects can provide a fertile ground for innovation and lead to patents and development of new products aiming at the market.

This study contributes to provide an insight view of how a student team PBL activity can grow over a decade if guided by faculty staff.