1,481 research outputs found
Competing roughening mechanisms in strained heteroepitaxy: a fast kinetic Monte Carlo study
We study the morphological evolution of strained heteroepitaxial films using
kinetic Monte Carlo simulations in two dimensions. A novel Green's function
approach, analogous to boundary integral methods, is used to calculate elastic
energies efficiently. We observe island formation at low lattice misfit and
high temperature that is consistent with the Asaro-Tiller-Grinfeld instability
theory. At high misfit and low temperature, islands or pits form according to
the nucleation theory of Tersoff and LeGoues.Comment: 4 pages, 4 figures, ReVTe
Trapping effects on inflation
We develop a Lagrangian approach based on the influence functional method so
as to derive self-consistently the Langevin equation for the inflaton field in
the presence of trapping points along the inflaton trajectory. The Langevin
equation exhibits the backreaction and the fluctuation-dissipation relation of
the trapping. The fluctuation is induced by a multiplicative colored noise that
can be identified as the the particle number density fluctuations and the
dissipation is a new effect that may play a role in the trapping with a strong
coupling. In the weak coupling regime, we calculate the power spectrum of the
noise-driven inflaton fluctuations for a single trapping point and studied its
variation with the trapping location. We also consider a case with closely
spaced trapping points and find that the resulting power spectrum is blue.Comment: 13 pages, 2 figure
Consumers’ Adoption of B2C E-Commerce in Macao
This research sets out to determine factors that influence consumers’ adoption of B2C E-commerce in Macao. While prior research has shown that there are many factors that influence E-commerce adoption, this research hypothesized that two variables – namely, trust and willingness to use credit cards for online transactions – influence E-commerce adoption in Macao. This research further hypothesized that trust and willingness to use credit card interact to influence adoption. Using data collected from a questionnaire survey, the results of this study found that the two hypothesized variables are positively related to intention to adopt E-commerce. The results also support the interaction effect. The nature of interaction showed that trust is related to E-commerce adoption only when willingness to use credit card for online transaction is high. Also, willingness to use credit card for online transaction is related to E-commerce adoption only when the level of trust is high. These results provide a richer understanding of the relationship between the hypothesized variables and Ecommerce adoption. This study also collected interview data related to Internet users’ adoption of E-commerce. The interview data provide a better understanding on why Macao people are afraid of using credit card for online transactions. The researchers gathered more information about interviewees’ credit card usage and habits, their attitudes toward credit card security, and their thoughts regarding identity theft. The interviews also uncovered other factors that may influence E-commerce adoption
Development of teaching beliefs and the focus of change in the process of pre-service ESL teacher education
This study sets out to investigate how pre-serviceESLteachers shape their beliefs in the process of experimenting with new teaching methods introduced in the teacher education programme. A 4-year longitudinal study was conducted with four randomly selectedESLpre-service teachers. Their theoretical orientations ofESLinstruction were tracked at intervals through a protocol which consisted of i) descriptive accounts, ii) surveys, iii) lesson plan analysis, iv) lesson recording and v) interviews. Despite the fact that these 4 student teachers had shown different theoretical orientations in the protocols, they shared similar patterns of instructional practices in the Teaching Practicum. It was also found that the new teaching method practiced in the teacher education programme was re-conceptualised by these student teachers in the actual teaching context because of the strong influence of their personal agency beliefs
SUMO ENHANCEMENT FOR VEHICULAR COMMUNICATION DEVELOPMENT
It is normal that every family is having at least one vehicle at their home as vehicles have become a daily needs for all of us. However, this also leads to the increased of road accidents where major causes are related to human errors which can be prevented. To tackle with this problem, vehicular ad hoc network (VANET) is introduced with the aim to make vehicles intelligent. In order to study the algorithm in VANET, a mobility simulator is needed for simulation purpose. In this case, SUMO is proved to be a good simulation tool in generating VANET environment while MATLAB is good for algorithm development. Yet, to develop a good simulation platform, modification on SUMO files are necessary. This paper discusses on the procedures in creating a left-hand traffic (LHT) simulation file that is suitable to be used in Malaysia. LHT simulation is not easy to achieve as modification on the road connection and traffic light files are required. This paper also showed the results of the simulation after SUMO files modification. Apart from that, this paper also showed the simulation of VANET environment using SUMO and MATLAB through a third party interfacing named TraCI4Matlab, which allows communication between MATLAB and SUMO simulator
A genetic algorithm for management of coding resources in VANET
This project aims to improve the throughput, energy consumption and overhead of vehicular ad hoc network (VANET) by optimising the network coding (NC) using Genetic Algorithm (GA). VANET shows a promising technology as it could enhance the traffic efficiency and promote traffic safety on the road systems. The conventional store-and-forward transmission protocol used in the intermediate node(s) simply stores the received packet and then send at a later time to the destination. However, the rapid changing in VANET topology has made the conventional store-and-forward approach inefficient to meet the throughput and reliability demand posed by VANET. Hence, NC is proposed to perform additional functions on the packet in the source or intermediate node(s). However, the chances to perform NC in wireless network is highly unlikely if the packet is not transmit to the potential NC node. Therefore, GA based network routing (GANeR) is embedded into network to search for shortest path from the source to the destination. It showed that the developed GANER in this work provides a better route with coding opportunities and reduces energy consumption in the network. The total energy consumed by GANER is 5.6% fewer than NC in wireless network transmission and forwarding structure (COPE)
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