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

Learn the basic properties and designs of modern VLSI devices, as well as the factors affecting performance, with this thoroughly updated second edition. The first edition has been widely adopted as a standard textbook in microelectronics in many major US universities and worldwide. The internationally-renowned authors highlight the intricate interdependencies and subtle tradeoffs between various practically important device parameters, and also provide an in-depth discussion of device scaling and scaling limits of CMOS and bipolar devices. Equations and parameters provided are checked continuously against the reality of silicon data, making the book equally useful in practical transistor design and in the classroom. Every chapter has been updated to include the latest developments, such as MOSFET scale length theory, high-field transport model, and SiGe-base bipolar devices.

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Fundamentals of Modern VLSI Devices

A prevalent and pervasive view of designing is that it can be modeled using variables and decisions made about what values should be taken by these variables. The activity of designing is carried out with the expectation that the designed artifact will operate in the natural world and the social world. These worlds impose constraints on the variables and their values; so, design could be described as a goal-oriented, constrained, decision- making activity. However, design distinguish- es itself from other similarly described activities not only by its domain but also by additional necessary features. Designing involves exploration, exploring what variables might be appropriate. The process of explo- ration involves both goal variables and deci- sion variables. In addition, designing involves learning: Part of the exploration activity is learning about emerging features as a design proceeds. Finally, design activity occurs within two contexts: the context within which the designer operates and the context produced by the developing design itself. The designer’s perception of what the context is affects the implication of the context on the design. The context shifts as the designer’s perceptions change. Design activity can be now characterized as a goal-oriented, con- strained, decision-making, exploration, and learning activity that operates within a con- text that depends on the designer’s percep- tion of the context.

Design Prototypes: A Knowledge Representation Schema for Design

Creativity: Flow and the Psychology of Discovery and Invention

Cognitive engineering

This paper summarizes the ongoing development of a Serious Application towards a 3D Virtual World (VW) for Telescope Complex Systems (TCS). Specifically, the underlying goal is to show how VWs can be useful for telescope maintenance by providing an intuitive means of complex data visualization and inference, equipment's teleoperation and by becoming a future platform for technical training and museographic Serious Games.

Towards A Serious Application for Telescope Maintenance.

Convergence is one of the most challenging issue to which satellite systems are faced to. They are suffering from a lack of packet-oriented communications which are known as being more suitable for convergence and introduction of new services. In this paper, we propose and analyze an IP convergent solution for communications by satellite. The protocol stack is based on the following protocols: MPEG2-TS, RTP, UDP, IP, MPLS, ULE, MPEG2-TS over DVB-S. The performance of this stack is studied in order to demonstrate that this solution can lead to the same QoS for multimedia streams as with the ordinary stack: MPEG2-TS/DVB-S even when the system is highly loaded. Once established, other cases were considered, for which background traffic such as VoIP packets are multiplexed with television flows. Delay and jitter have been studied. It is shown that our solution leads to satisfying results, comparable to the ones derived in a classical DVB-S system.

Emmanuel Dubois

Papers

Towards A Serious Application for Telescope Maintenance.

QoS of television broadcast traffic over convergent IP solution for DVB-S satellite system