2,357 research outputs found
Study of a family of higher order nonlocal degenerate parabolic equations: from the porous medium equation to the thin film equation
In this paper, we study a nonlocal degenerate parabolic equation of order
{\alpha} + 2 for 0<{\alpha}<2. The equation is a generalization of the one
arising in the modeling of hydraulic fractures studied by Imbert and Mellet in
2011. Using the same approach, we prove the existence of solutions for this
equation for 0<{\alpha}<2 and for nonnegative initial data satisfying
appropriate assumptions. The main difference is the compactness results due to
different Sobolev embeddings. Furthermore, for {\alpha} > 1, we construct a
nonnegative solution for nonnegative initial data under weaker assumptions.Comment: arXiv admin note: text overlap with arXiv:1001.5105 by other author
Differences in intention to use educational RSS feeds between Lebanese and British students: A multi‑group analysis based on the technology acceptance model
Really Simple Syndication (RSS) offers a means for university students to receive timely updates from virtual learning environments. However, despite its utility, only 21% of home students surveyed at a university in Lebanon claim to have ever used the technology. To investigate whether national culture could be an influence on intention to use RSS, the survey was extended to British students in the UK. Using the Technology Adoption Model (TAM) as a research framework, 437 students responded to a questionnaire containing four constructs: behavioral intention to use; attitude towards benefit; perceived usefulness; and perceived ease of use. Principle components analysis and structural equation modelling were used to explore the psychometric qualities and utility of TAM in both contexts. The results show that adoption was significantly higher, but also modest, in the British context at 36%. Configural and metric invariance were fully supported, while scalar and factorial invariance were partially supported. Further analysis shows significant differences between perceived usefulness and perceived ease of use across the two contexts studied. Therefore, it is recommended that faculty demonstrate to students how educational RSS feeds can be used effectively to increase awareness and emphasize usefulness in both contexts
Higgs quartic coupling and neutrino sector evolution in 2UED models
Two compact universal extra dimensional models are an interesting class of
models for different theoretical and phenomenological issues, such as the
justification of having three standard model fermion families, suppression of
proton decay rate, dark matter parity from relics of the 6-dimensional Lorentz
symmetry, origin of masses and mixings in the standard model. However, these
theories are merely effective ones, with typically a reduced range of validity
in their energy scale. We explore two limiting cases of the three standard
model generations all propagating in the bulk or all localised to a brane, from
the point of view of renormalisation group equation evolutions for the Higgs
sector and for the neutrino sector of these models. The recent experimental
results of the Higgs boson from the LHC allow, in some scenarios, stronger
constraints on the cut-off scale to be placed, from the requirement of the
stability of the Higgs potential.Comment: 9 pages, 6 figures, accepted for publication in European Physical
Journal C. arXiv admin note: text overlap with arXiv:1306.485
Designing Guidelines to Discover Causes of Delays in Construction Projects: The Case of Lebanon
Construction projects in developing countries have the priority among other projects as they are considered safe investments in an unpredictable market. Due to this prioritization, it has become increasingly important that such projects are managed in accordance with internationally accepted management best practice. Project managers of construction projects in developing countries face difficulties in effectively monitoring the progress of projects they are responsible for due to many variables. The purpose of this study is to investigate the causes of delays in the construction projects that were covered in the considered literature and conduct qualitative research to investigate their relevance by interviewing project managers of actual projects in Lebanon. Based on the literature review and from the recommendations recorded during interviews, the researcher aims to create a set of guidelines that will improve the manner in which project managers can adapt to, discover and deal with project delays. These guidelines can be utilized as an early warning system concerning delays in construction projects
Recommended from our members
The effects of individual-level culture and demographic characteristics on e-learning acceptance in Lebanon and England: A structural equation modeling approach
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel UniversityDue to the rapid growth of Internet technology, universities and higher educational institutions around the world are investing heavily in web-based learning systems to support their traditional teaching and to improve their students’ learning experience and performance. However, the success of an e-learning system depends on the understanding of certain antecedent factors that influence the students’ acceptance and usage of such e-learning systems. Previous research indicates that technology acceptance models and theories may not be applicable to all cultures as most of them have been developed in the context of developed countries and particularly in the U.S. So far little research has investigated the important role that social, cultural, organizational and individual factors may play in the use and adoption of the e-learning systems in the context of developing countries and more specifically there is almost absence of this type of research in Lebanon.
This study aims to fill this gap by developing and testing an amalgamated conceptual framework based on Technology Acceptance Model (TAM) and other models from social psychology, such as Unified Theory of Acceptance and Use of Technology (UTAUT) and TAM2 that captures the salient factors influencing the user adoption and acceptance of web-based learning systems. This framework has been applied to the study of higher educational institutions in the context of developing as well as developed countries (e.g. Lebanon and UK). Additionally, the framework investigates the moderating effect of Hofstede’s four cultural dimensions at the individual level and a set of individual differences on the key determinants that affect the behavioural intention to use e-learning. A total of 1197 questionnaires were received from students who were using web-based learning systems at higher educational institutions in Lebanon and the UK with opposite scores on cultural dimensions. Confirmatory Factor Analysis (CFA) was used to perform reliability and validity checks, and Structural Equation Modeling (SEM) in conjunction with multi-group analysis method was used to test the hypothesized conceptual model. As hypothesized, the findings of this study revealed that perceived usefulness (PU), perceived ease of use (PEOU), subjective norms (SN), perceived quality of work Life (QWL), self-efficacy (SE) and facilitating conditions (FC) to be significant determinants of behavioural intentions and usage of e-learning system for the Lebanese and British students. QWL; the newly added variable; was found the most important factor in explaining the causal process in the model for both samples. Our findings proved that there are differences between Lebanese and British students in terms of PEOU, SE, SN, QWL, FC and AU; however no differences were detected in terms of PU and BI. The results of the MGA show that cultural dimensions as well as demographic factors had a partially moderated effect on user acceptance of e-learning. Overall, the proposed model achieves acceptable fit and explains for 68% of the British sample and 57% of the Lebanese sample of its variance which is higher than that of the original TAM. Our findings suggest that individual, social, cultural and organisational factors are important to consider in explaining students’ behavioural intention and usage of e-learning environments. The findings of this research contribute to the literature by validating and supporting the applicability of our extended TAM in the Lebanese and British contexts and provide several prominent implications to both theory and practice on the individual, organizational and societal levels.Altajir Trus
About the existence of oriented paths with three blocks
A path P(k,l,r) is an oriented path consisting of k forward arcs, followed by
l backward arcs, and then by r forward arcs. We prove the existence of any
oriented path of length n-1 with three blocks having the middle block of length
one in any (2n-3)- chromatic digraph, which is an improvement of the latest
bound reached in this case. Concerning the general case of paths with three
blocks, we prove, after partitioning the problem into three cases according to
the value of k,l and r that the chromatic number of digraphs containing no
P(k,l,r) of length n-1 is bounded above by 2(n-1)+r, 2(n-1)+l+r-k and
2(n+l-1)-k in the three cases respectively
- …