Accessibility evaluation of chats and forums in e-learning environments

Proceedings of: 2013 International Conference on Frontiers in Education: Computer Science & Computer Engineering (FECS'13): WORLDCOMP'13, July 22-25, 2013, Las Vegas, Nevada (USA)Collaborative learning is useful for students in their learning process. Nowadays, most e-learning systems include Computer Supported Collaborative Learning (CSCL) tools like chats and forums; however, are they accessible for everybody? This paper presents a heuristic evaluation of accessibility of two CSCL tools (chat and forum) in four web-based, open-source Learning Content Management Systems (LCMS): Moodle, ATutor, dotLRN and Claroline. The evaluation results show that the CSCL tools evaluated present accessibility barriers which are a handicap for many students who want to use the LCMSs Moreover, some recommendations are offered in order to improve the accessibility of the evaluated tools. Considering these recommendations in the development of the evaluated tools, all students could participate actively in the collaborative tasks proposed by teachersThis research work has been supported by the Regional Government of Madrid under the Research Network MA2VICMR (S2009/TIC-1542) and by the Spanish Ministry of Economy under the project MULTIMEDICA (TIN2010-20644-C03-01)Publicad

Towards Generic Monitors for Object-Oriented Real-Time Maude Specifications

Non-Functional Properties (NFPs) are crucial in the design of software. Specification of systems is used in the very first phases of the software development process for the stakeholders to make decisions on which architecture or platform to use. These specifications may be an- alyzed using different formalisms and techniques, simulation being one of them. During a simulation, the relevant data involved in the anal- ysis of the NFPs of interest can be measured using monitors. In this work, we show how monitors can be parametrically specified so that the instrumentation of specifications to be monitored can be automatically performed. We prove that the original specification and the automati- cally obtained specification with monitors are bisimilar by construction. This means that the changes made on the original system by adding monitors do not affect its behavior. This approach allows us to have a library of possible monitors that can be safely added to analyze different properties, possibly on different objects of our systems, at will.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tech. Spanish MINECO/FEDER project TIN2014-52034-R, NSF Grant CNS 13-19109

Evaluation Comparison of Mesh-Based routing Protocols in MANET

A multicast routing protocol manages group membership and controls the path that multicast data takes over the network in mobile ad hoc network. This process is done through either tree-based or mesh-based protocols. The mesh-based protocols are more reliable and robust against the tree based protocols. One of the most used on-demand multicast routing protocol is ODMRP (On-Demand Routing Protocol). However, it has the significant overhead due to redundant data delivery group and path maintenance. This overhead has been eliminated through the forwarding node reduction and link break time prediction algorithm (FNRLP). This work aims to exhibit the performance characteristics of mesh-based on-demand multicast routing protocols ODMRP and ODMRP-FNRLP

Assessment of Response Time for New Multi Level Feedback Queue Scheduler

Response time is one of the characteristics of scheduler, happens to be a prominent attribute of any CPU scheduling algorithm. The proposed New Multi Level Feedback Queue [NMLFQ] Scheduler is compared with dynamic, real time, Dependent Activity Scheduling Algorithm (DASA) and Lockes Best Effort Scheduling Algorithm (LBESA). We abbreviated beneficial result of NMLFQ scheduler in comparison with dynamic best effort schedulers with respect to response time.Comment: 7 pages, 5 figure

A basic tool for the modeling of Marked-Controlled Reconfigurable Petri Nets

In previous studies, we have introduced marked-controlled net rewriting systems and a subclass of these called marked-controlled reconfigurable Petri nets. In a marked-controlled net rewriting system, a system configuration is described as a Petri net, and a change in configuration is described as a graph rewriting rule. A marked-controlled reconfigurable Petri net is a marked-controlled net rewriting system where a change in configuration amounts to a modification in the flow relations of the places in the domain of the involved rule in accordance with this rule, independently of the context in which this rewriting applies. In both models, the enabling of a rule not only depends on the net topology, but also depends on the net marking according to control places. Even though the expressiveness of Petri nets and marked-controlled reconfigurable Petri nets is the same, with marked-controlled reconfigurable Petri nets, we can easily and directly model concurrent and distributed systems that change their structure dynamically. In this article, we present MCReNet, a tool for the modeling and verification of marked-controlled reconfigurable Petri nets

A distributed data component for the Open Modeling Interface

As the volume of collected data continues to increase in the environmental sciences, so too does the need for effective means for accessing those data. We have developed an Open Modeling Interface (OpenMI) data component that retrieves input data for model components from environmental information systems and delivers output data to those systems. The adoption of standards for both model component input–output interfaces and web services make it possible for the component to be reconfigured for use with different linked models and various online systems. The data component employs three techniques tailored to the unique design of the OpenMI that enable efficient operation: caching, prefetching, and buffering, making it capable of scaling to large numbers of simultaneous simulations executing on a computational grid. We present the design of the component, an evaluation of its performance, and a case study demonstrating how it can be incorporated into modeling studies

Технологія віртуалізації. Динамічна реконфігурація ресурсів обчислювального кластера

На основании выполненного анализа современных платформ аппаратно-программной виртуализации обоснована целесообразность использования и исследования виртуальных машин на платформе Microsoft Hyper-V R2 в качестве узлов вычислительного кластера. Концепция создания гибких гомогенных архитектур кластерных систем углублена за счет возможности формирования динамически реконфигурируемой кластерной вычислительной системы с использованием механизмов виртуализации платформы Microsoft Hyper-V. Показана актуальность использования аппаратной платформы персональных компьютеров и серверов для реконфигурации ресурсов вычислительных кластеров.На основі виконаного аналізу сучасних платформ апаратно-програмної віртуалізації обґрунтовано доцільність використання і дослідження віртуальних машин на платформі Microsoft Hyper-V R2 як вузлів обчислювального кластера. Концепцію створення гнучких гомогенних архітектур кластерних систем поглиблено за рахунок можливості формування динамічно реконфігурованої кластерної обчислювальної системи з використанням механізмів віртуалізації платформи Microsoft Hyper-V. Показано актуальність використання апаратної платформи персональних комп’ютерів і серверів для реконфігурації ресурсів обчислювальних кластерів.On the basis of performed analysis of modern hardware and software virtualization platforms it is proved the practicability of usage and researching of virtual machines on the Microsoft Hyper-V R2 platform as a compute cluster nodes. The concept of flexible homogeneous cluster architectures construction was expanded with ability of dynamically reconfigurable cluster computing system implementation using Microsoft Hyper-V technology virtualization features. The urgency of hardware platform of personal computers and servers for reconfiguration of the resources of computing clusters is shown

MPI Applications on Grids: A Topology-Aware Approach

Large Grids are build by aggregating smaller parallel machines through a public long-distance interconnection network (such as the Internet). Therefore, their structure is intrinsically hierarchical. Each level of the network hierarchy gives performances which differ from the other levels in terms of latency and bandwidth. MPI is the de facto standard for programming parallel machines, therefore an attractive solution for programming parallel applications on this kind of grids. However, because of the aforementioned differences of communication performances, the application continuously communicates back and forth between clusters, with a significant impact on performances. In this report, we present an extension of the information provided by the run-time environment of an MPI library, a set of efficient collective operations for grids and a methodology to organize communication patterns within applications with respect to the underlying physical topology, and implement it in a geophysics application