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

Algorithm model and execution based on Petri Nets in an heterogeneous parallel computer

Multicore - MultiGPU systems are frequently used in supercomputers design. The heterogeneity between both types of processors is a source of problems for the parallel programming: disparity in processing throughput and memory availability. While some problems are faster executed in a GPGPU, when its data size exceeds the memory available, data partition must to be done in order to resolve, and become desirable to use both types of processors. In this paper we present a solution based on Petri Nets to model the algorithm and to guide the execution, balancing the load between the CPUs cores and GPGPUs. The matrix multiplication algorithm is used as testbed. Tests confirm the goodness of the model and highlight the difficulties to address the problem.http://carla2014.hpclatam.orgFil: Wolfmann, Gustavo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Laboratorio de Computación; Argentina.Fil: De Giusti, Armando. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Laboratorio de Computación; Argentina.Hardware y Arquitectura de Computadora

Increased reliability of computer system by using fault tolerance technique

Fault-tolerant computing began between 1965 and 1970, probably with the highly reliable and widely available AT&T electronic switching systems

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

Prevention of information harvesting in a cloud services environment

We consider a cloud data storage involving three entities, the cloud customer, the cloud business centre which provides services, and the cloud data storage centre. Data stored in the data storage centre comes from a variety of customers and some of these customers may compete with each other in the market place or may own data which comprises confidential information about their own clients. Cloud staff have access to data in the data storage centre which could be used to steal identities or to compromise cloud customers. In this paper, we provide an efficient method of data storage which prevents staff from accessing data which can be abused as described above. We also suggest a method of securing access to data which requires more than one staff member to access it at any given time. This ensures that, in case of a dispute, a staff member always has a witness to the fact that she accessed data

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 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