Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fast parallel algorithms for short-range molecular dynamics

Scientific discovery learning is a highly self-directed and constructivistic form of learning. A computer simulation is a type of computer-based environment that is well suited for discovery learning, the main task of the learner being to infer, through experimentation, characteristics of the model underlying the simulation. In this article we give a review of the observed effectiveness and efficiency of discovev learning in simulation environments together with problems that learners may encounter in discovery learning, and we discuss how simulations may be combined with instructional support in order to overcome these problems.

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Scientific Discovery Learning with Computer Simulations of Conceptual Domains

Cognitive load is a theoretical notion with an increasingly central role in the educational research literature. The basic idea of cognitive load theory is that cognitive capacity in working memory is limited, so that if a learning task requires too much capacity, learning will be hampered. The recommended remedy is to design instructional systems that optimize the use of working memory capacity and avoid cognitive overload. Cognitive load theory has advanced educational research considerably and has been used to explain a large set of experimental findings. This article sets out to explore the open questions and the boundaries of cognitive load theory by identifying a number of problematic conceptual, methodological and application-related issues. It concludes by presenting a research agenda for future studies of cognitive load.

/pdf/cognitive-load-theory-educational-research-and-instructional-xr5ans2vda.pdf

Cognitive load theory, educational research, and instructional design: some food for thought

Computer Controlled Systems: Theory and Design

Research has consistently shown that inquiry-based learning can be more effective than other, more expository instructional approaches as long as students are supported adequately. But what type of guidance is adequate, and for whom? These questions are difficult to answer as most previous research has only focused on one type of guidance and one type of learner. This meta-analysis therefore synthesized the results of 72 studies to compare the effectiveness of different types of guidance for different age categories. Results showed facilitative overall effects of guidance on learning activities (d = 0.66, 95% CI [0.44, 0.88]), performance success (d = 0.71, 95% CI [0.52, 0.90]), and learning outcomes (d = 0.50, 95% CI [0.37, 0.62]). Type of guidance moderated the effects on performance success but not on the other two outcome measures. Considerable variation was found in the effects of guidance on learning activities, but the relatively low number of studies do not allow for any definitive conclusion on possible age-related differences.

/pdf/meta-analysis-of-inquiry-based-learning-effects-of-guidance-3qc3oxe7im.pdf

Meta-Analysis of Inquiry-Based Learning: Effects of Guidance

Easy Java Simulations: a software tool to create scientific simulations in Java

This paper introduces a Web-based control laboratory for experimentation on a nonlinear multiple-input-multiple-output (MIMO) system: the three-tank plant. Using this application, automation technician students can learn in a practical way many fundamental aspects of control processes. The client-side of the virtual laboratory has been developed using the programming support provided by Easy Java Simulations (EJS), an open-source tool for teachers with limited programming skills who want to create Java applications and applets. The lab has been integrated in the collaborative Web-based experimentation environment eMersion which provides more flexibility for the students performing the laboratory experiments.

/pdf/development-of-a-web-based-control-laboratory-for-automation-3fwe787qlo.pdf

Development of a Web-Based Control Laboratory for Automation Technicians: The Three-Tank System

New information technologies provide great opportunities for education. One such opportunity is the use of remote control laboratories for teaching students about control systems. This paper describes the creation of interactive remote laboratories (RLs). Two main software tools are used: Simulink and Easy Java Simulations (EJS). The first is a widely used tool in the control community, whereas the second is an authoring tool designed to build interactive applications in Java without special programming skills. The RLs created by this approach give students the opportunity to perform experiments with real equipment from any location, at any time, and at their own pace. The paper ends with an evaluation of this approach according to students' criteria and academic results.

Developing a remote laboratory for engineering education

Discovery learning is generally seen as a promising but demanding mode of learning that, in most cases, can only be successful if students are guided in the discovery process. The present article discusses a study on discovery learning with a computer simulation environment in the physics domain of collisions. In the learning environment, which is called Collision, students learned about collisions where two particles move in the same direction and interact via a conservative force in such a way that the total mechanical energy is conserved. In the experiment we conducted with Collision, we evaluated the effects of adding two different ways to guide students: model progression, in which the model is presented in separate parts; and assignments, small exercises that the student can choose to do. The effect of providing assignments and model progression was evaluated by comparing the learning behavior and learning results over three experimental conditions in which different versions of the simulation environment were presented: pure simulation, simulation plus assignments, and simulation plus model progression and assignments. Students' use of the environment was logged, their subjectively experienced workload was measured on-line, and their learning was assessed using a number of assessment procedures. Providing assignments with the simulation improved students' performance on one aspect of a so-called intuitive knowledge test. Providing the students with model progression did not have an effect. A subjective workload measure indicated that expanding the simulation with assignments and model progression did not raise the workload experienced by the students.

The Integration of Computer Simulation and Learning Support: An Example from the Physics Domain of Collisions

Web-based learning environments are becoming increasingly popular in higher education. One of the most important web-learning resources is the virtual laboratory (VL), which gives students an easy way for training and learning through the Internet. Moreover, on-line collaborative communication represents a practical method to transmit the knowledge and experience from the teacher to students overcoming physical distance and isolation. Considering these facts, the authors of this document have developed a new dynamic collaborative e-learning system which combines the main advantages of virtual laboratories and collaborative learning practices. In this system, the virtual laboratories are based on Java applets which have embedded simulations developed in Easy Java Simulations (EJS), an open-source tool for teachers who do not need complex programming skills. The collaborative e-learning is based on a real-time synchronized communication among these Java applets. Therefore, this original approach provides a new tool which integrates virtual laboratories inside a synchronous collaborative e-learning framework. This paper describes the main features of this system and its successful application in a distance education environment among different universities from Spain.

https://rua.ua.es/dspace/bitstream/10045/10125/4/Paper_CE_Final.pdf

Francisco Esquembre

Papers

Easy Java Simulations: a software tool to create scientific simulations in Java

Development of a Web-Based Control Laboratory for Automation Technicians: The Three-Tank System

Developing a remote laboratory for engineering education

The Integration of Computer Simulation and Learning Support: An Example from the Physics Domain of Collisions

Real-time collaboration of virtual laboratories through the Internet