Tan Fong Ang

Scientific Workflows: Moving Across Paradigms

Modern scientific collaborations have opened up the opportunity to solve complex problems that require both multidisciplinary expertise and large-scale computational experiments. These experiments typically consist of a sequence of processing steps that need to be executed on selected computing platforms. Execution poses a challenge, however, due to (1) the complexity and diversity of applications, (2) the diversity of analysis goals, (3) the heterogeneity of computing platforms, and (4) the volume and distribution of data. A common strategy to make these in silico experiments more manageable is to model them as workflows and to use a workflow management system to organize their execution. This article looks at the overall challenge posed by a new order of scientific experiments and the systems they need to be run on, and examines how this challenge can be addressed by workflows and workflow management systems. It proposes a taxonomy of workflow management system (WMS) characteristics, including aspects previously overlooked. This frames a review of prevalent WMSs used by the scientific community, elucidates their evolution to handle the challenges arising with the emergence of the “fourth paradigm,” and identifies research needed to maintain progress in this area.

Survey on network virtualization using openflow : Taxonomy, opportunities, and open issues

The popularity of network virtualization has recently regained considerable momentum because of the emergence of OpenFlow technology. It is essentially decouples a data plane from a control plane a ...

Issues of Establishing a Campus-wide Computational Grid Infrastructure in the GERANIUM Project

A campus-wide grid and cluster infrastructure using the Rocks clustering software is established. The infrastructure, namely Grid-Enabled Research Network and Info-structure of University of Malaya (GERANIUM), comprises five distinct clusters located at different faculties and institutes. In this paper, the GERANIUM topology and architecture are presented, and issues and experiences concerned are discussed.

Learning through intuitive interface: A case study on preschool learning

Abstract For a child, playing is not only an act of fun, but also a way of learning. Long hours of study in a classroom without playing only serve to make the children detest learning. A current interest of research is to integrate the learning process with the latest technology to engage children with learning and playing. Game-based learning (GBL) is one of the approaches that utilises the gaming environment to attract the students attention and increase participation throughout the process of learning. We proposed an intervention program that used voice and gesture-based interactive virtual learning environment (VGVLE) based on GBL framework to teach colour and shape to preschool children. The program with quasi-experimental design (N = 84) was conducted to evaluate the effectiveness of the proposed approach in promoting preschool learning when compared with the traditional classroom teaching approach. Our findings show that pre-schoolers who learnt with the proposed approach surpassed those who learnt with the classroom approach. Besides that, the gap in learning performance was also reduced.

Graphical password: prevent shoulder-surfing attack using digraph substitution rules

In this paper, a new scheme that uses digraph substitution rules to conceal the mechanism or activity required to derive password-images is proposed. In the proposed method, a user is only required to click on one of the pass-image instead of both pass-images shown in each challenge set for three consecutive sets.While this activity is simple enough to reduce login time, the images clicked appear to be random and can only be obtained with complete knowledge of the registered password along with the activity rules. Thus, it becomes impossible for shoulder-surfing attackers to obtain the information about which password images and pass-images are used by the user. Although the attackers may know about the digraph substitution rules used in the proposed method, the scenario information used in each challenge set remains. User study results reveal an average login process of less than half a minute. In addition, the proposed method is resistant to shoulder-surfing attacks.

An enhanced embedding method using inter-sentence, inter-word, end-of-line and inter-paragraph spacing

This paper discusses a novel embedding mechanism which uses hybrid methods of inter-sentence, inter-word, end-of-line and inter-paragraph spacing to embed the secret message. From the test cases analysis, the proposed system has proven that it is able to hide larger capacity compared to other current steganographic tools such as wbStego4open, SNOW and Spacemimic. From the experimental results, the proposed method is able to improve the embedding capacity approximately 1 to 2 times compared to other steganographic tools by using plain text as payload. In terms of using image files as payload, the proposed method is also able to reduce the stego-text produced from 0.1 to 1 time as compared to other steganographic tools when the payload size is less than 100 kB.