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

Sub-0.1-/spl mu/m planar and gate recessed MOSFET's are investigated using both drift-diffusion and Monte Carlo simulations. In nonplanar devices, the influence of the gate corner explains that the threshold voltage roll-off can be almost suppressed. A steeper subthreshold slope (low swing) is also obtained for a channel length shorter than 50 nm when the recessed channel MOSFET is compared to its planar counterpart. The influence of the corner effect on high-current performances is also considered in relation with the electric field profile along the Si/SiO/sub 2/ interface.

Short-channel effect immunity and current capability of sub-0.1-micron MOSFET's using a recessed channel

Scanning tunneling microscopy (STM) and atomic force microscopy (AFM) nanolithography techniques based on local oxidation of silicon/titanium and electron beam exposure of PMMA are described. It is shown that a 10 nm resolution can routinely be achieved using tapping-mode AFM-based anodization of silicon and titanium operated in air. The thickness and width of oxide stripes are studied as a function of the applied probe-sample voltage and the speed of the tip. Exposure of PMMA resist (950 K, 3%) is also demonstrated using contact-mode AFM to control the tip/surface interaction through a constant force and field emission of electrons to expose the resist.

Nanometer scale lithography on silicon, titanium and PMMA resist using scanning probe microscopy

We present the design and evaluation of the Roly-Poly Mouse (RPM), a rolling input device that combines the advantages of the mouse (position displacement) and of 3D devices (roll and rotation) to unify 2D and 3D interaction. Our first study explores RPM gesture amplitude and stability for different upper shapes (Hemispherical, Convex) and hand postures. 8 roll directions can be performed precisely and their amplitude is larger on Hemispherical RPM. As minor rolls affect translation, we propose a roll correction algorithm to support stable 2D pointing with RPM. We propose the use of compound gestures for 3D pointing and docking, and evaluate them against a commercial 3D device, the SpaceMouse. Our studies reveal that RPM performs 31% faster than the SpaceMouse for 3D pointing and equivalently for 3D rotation. Finally, we present a proof-of-concept integrated RPM prototype along with discussion on the various technical challenges to overcome to build a final integrated version of RPM.

/pdf/the-roly-poly-mouse-designing-a-rolling-input-device-4lt6vdu7ph.pdf

The Roly-Poly Mouse: Designing a Rolling Input Device Unifying 2D and 3D Interaction

One of the recent design goals in Human Computer Interaction has been to extend the sensory- motor capabilities of computer systems to combine the real and the virtual in order to assist the user in his environment. Such systems are called Augmented Reality (AR). Although AR systems are becoming more prevalent we still do not have a clear understanding of this interaction paradigm. In this paper we propose OPAS as a generic framework for classifying existing AR systems. Computer Assisted Medical Interventions (CAMI), for which the added value of AR has been demonstrated by experience, are discussed in light of OPAS. We illustrate OPAS using our system, CASPER (Computer ASsisted PERicardial puncture), a CAMI system which assists in surgical procedures (pericardial punctures).

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Classification Space for Augmented Surgery, an Augmented Reality Case Study

We investigate Er silicide formed on n-type silicon. In order to protect the Er from oxidation during the formation of Er silicide in non-UHV conditions, a Pt layer is deposed successively on top of Er layer. Surprisingly, we observe that Pt remains essentially unaffected in the formation of Er silicide at temperatures lower than 700 degreesC. We find that silicidation process is fully completed by rapid thermal annealing at 500 degreesC. A simplified method of analysis considering the final Schottky barrier MOSFET application has been used to characterize the Schottky barrier of the PtEr-stack silicide system. A very low apparent Schottky barrier (smaller than 0.1 eV) on a n-type silicon substrate with a concentration of 1.4 x 10(16) cm(-3) in the active region has been obtained. (C) 2003 Elsevier Ltd. All rights reserved.

Emmanuel Dubois

Papers

Short-channel effect immunity and current capability of sub-0.1-micron MOSFET's using a recessed channel

Nanometer scale lithography on silicon, titanium and PMMA resist using scanning probe microscopy

The Roly-Poly Mouse: Designing a Rolling Input Device Unifying 2D and 3D Interaction

Classification Space for Augmented Surgery, an Augmented Reality Case Study

Very low Schottky barrier to n-type silicon with PtEr-stack silicide