Asymptotic behaviour of the Einstein-Vlasov system with a positive cosmological constant

We study locally spatially homogeneous solutions of the Einstein-Vlasov system with a positive cosmological constant. First the global existence of solutions of this system and the casual geodesic completeness are shown. Then the asymptotic behaviour of solutions in the future time is investigated in various aspects.Comment: 17 page

The Einstein-Vlasov system with a scalar field

We study the Einstein-Vlasov system coupled to a nonlinear scalar field with a nonnegative potential in locally spatially homogeneous spacetime, as an expanding cosmological model. It is shown that solutions of this system exist globally in time. When the potential of the scalar field is of an exponential form, the cosmological model corresponds to accelerated expansion. The Einstein-Vlasov system coupled to a nonlinear scalar field whose potential is of an exponential form shows the causal geodesic completeness of the spacetime towards the future. The asymptotic behaviour of solutions of this system in the future time is analysed in various aspects, which shows power-law expansion.Comment: 30 page

The non-relativistic limit of the Nordstr\"om-Vlasov system

The Nordstr\"om-Vlasov system provides an interesting relativistic generalization of the Vlasov-Poisson system in the gravitational case, even though there is no direct physical application. The study of this model will probably lead to a better mathematical understanding of the class of non-linear systems consisting of hyperbolic and transport equations. In this paper it is shown that solutions of the Nordstr\"om-Vlasov system converge to solutions of the Vlasov-Poisson system in a pointwise sense as the speed of light tends to infinity, providing a further and rigorous justification of this model as a \textit{genuine} relativistic generalization of the Vlasov-Poisson system.Comment: 19 page

FiFo: Fishbone Forwarding in Massive IoT Networks

Massive Internet of Things (IoT) networks have a wide range of applications, including but not limited to the rapid delivery of emergency and disaster messages. Although various benchmark algorithms have been developed to date for message delivery in such applications, they pose several practical challenges such as insufficient network coverage and/or highly redundant transmissions to expand the coverage area, resulting in considerable energy consumption for each IoT device. To overcome this problem, we first characterize a new performance metric, forwarding efficiency, which is defined as the ratio of the coverage probability to the average number of transmissions per device, to evaluate the data dissemination performance more appropriately. Then, we propose a novel and effective forwarding method, fishbone forwarding (FiFo), which aims to improve the forwarding efficiency with acceptable computational complexity. Our FiFo method completes two tasks: 1) it clusters devices based on the unweighted pair group method with the arithmetic average; and 2) it creates the main axis and sub axes of each cluster using both the expectation-maximization algorithm for the Gaussian mixture model and principal component analysis. We demonstrate the superiority of FiFo by using a real-world dataset. Through intensive and comprehensive simulations, we show that the proposed FiFo method outperforms benchmark algorithms in terms of the forwarding efficiency.Comment: 13 pages, 16 figures, 5 tables; to appear in the IEEE Internet of Things Journal (Please cite our journal version that will appear in an upcoming issue.

Investigation on marine LNG propulsion systems for LNG carriers through an enhanced hybrid decision making model

Since the use of LNG as an alternative fuel has drawn increasing attention from the marine industry, this paper aimed to evaluate three competitive LNG fuelled engine systems: ultra-steam turbine, four-stroke medium speed engine, and two-stroke low-speed engine systems. To achieve this goal, the paper developed an enhanced hybrid decision-making model which was applied to integrate the economic, environmental and technical performance of these systems. This model can be represented as a semi-quantitative multi-criteria decision making process in combination of several novel techniques, particularly ‘life cycle cost assessment’ for economic analysis, ‘life cycle assessments’ for environmental analysis, ‘fuzzy order preference by similarity to ideal solution’ for technical analysis and ‘fuzzy analytic hierarchy process’ for multi-criteria decision making. A case study with a 174K LNG carrier has revealed that the two-stroke low-speed engine system is the most effective overall and suggested that this type of engine system will hold the lead over the other candidates in the large LNG carrier market. It has also demonstrated the effectiveness of the proposed model to improve the inherent subjectivity in existing qualitative multi-criteria decision-making processes by guiding the overall process in a more objective direction. Finally, this paper has revealed an underlying novelty of the proposed model to enhance the level of confidence level in the decision by expanding our short-term perspective to the holistic one

Exploring Arts Based Assessments for Relevancy in Art Therapy Research

This paper explores the integration of art assessments with cancer patients as a tool for determining potential scholarly value. Qualitative data was collected from two clinicians who ran weekly art therapy groups with women who are undergoing or who have survived breast cancer treatment. Both groups were 10 week modules structured as open studio groups, and each clinician was subsequently interviewed by the researchers who used a series of formatted questions to assess how the four art assessments were offered to participants, how participants responded to the invitation to engage in assessments, and how the clinician’s reflected on patients’ experiences of the assessments. The qualitative data collected was assessed to deepen the understanding of how clinician’s imagined the art assessments could be clinically useful and/or potentially valuable for research. These findings were then examined and connected to findings in the literature that indicate the importance of sensitivity in regard to the unique lived experience of a cancer diagnosis, and the significance of offering control and transparency whenever possible to patients. Researchers concluded that offering art assessments in traditional context, when presented by clinicians who are attuned and considerate to the needs and impacts such assessments can have on patients, could deepen opportunities for exploring clinically efficaciousness alongside cultural and contextual sensitivity. Future research should continue to explore how clinician style can be clinically relevant and the impact art assessments could have on both research and clinical work

Feasibility and Usability of Tele-interview for Medical Residency Interview

Every year in the United States, medical students and residency programs dedicate millions of dollars to the residency matching process. On-site interviews for training positions involve tremendous financial investment, and time spent detracts from educational pursuits and clinical responsibilities. Students are usually required to fund their own travel and accommodations, adding additional financial burdens to an already costly medical education. Similarly, residency programs allocate considerable funds to interview-day meals, tours, staffing, and social events. With the rapid onslaught of innovations and advancements in the field of telecommunication, technology has become ubiquitous in the practice of medicine. Internet applications have aided our ability to deliver appropriate, evidence-based care at speeds previously unimagined. Wearable medical tech allows physicians to monitor patients from afar, and telemedicine has emerged as an economical means by which to provide care to all corners of the world. It is against this backdrop that we consider the integration of technology into the residency application process. This article aims to assess the implementation of technology in the form of web-based interviewing as a viable means by which to reduce the costs and productivity losses associated with traditional in-person interview days