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.

/pdf/fundamentals-of-modern-vlsi-devices-471xd7l9pf.pdf

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

Investigation on the platinum silicide Schottky barrier height modulation using a dopant segregation approach

The low temperature electrical behavior of adjacent silicide/Si Schottky contacts with or without dopant segregation is investigated. The electrical characteristics are very well modeled by thermionic-field emission for non-segregated contacts separated by micrometer-sized gaps. Still, an excess of current occurs at low temperature for short contact separations or dopant-segregated contacts when the voltage applied to the device is sufficiently high. From two-dimensional self-consistent non-equilibrium Green's function simulations, the dependence of the Schottky barrier profile on the applied voltage, unaccounted for in usual thermionic-field emission models, is found to be the source of this deviation.

Low temperature tunneling current enhancement in silicide/Si Schottky contacts with nanoscale barrier width

PtSi is very attractive for the future VLSI technologies as a contact silicide for nanometric pMOS devices because of its low barrier height to p-type Si, low silicon consumption, and low temperature formation (1,2). Also, the integration of PtSi as metallic source and drain in Schottky-Barrier p-type MOSFET appears as a performance booster to leverage the tight constraints associated to the junction module engineering (3,4).

An Original Selective Etch of Pt vs. PtSi using a Low Temperature Germanidation Process

Electrical characteristics of semi-recessed and fully-recessed LOCOS isolation techniques are analyzed. Two-dimensional process/device simulations, performed with the IMPACT package, have demonstrated the effect of the Si/SiO 2 interface shape on isolation efficiency. An excellent agreement has been found between simulations and measurements for the studied structures.

/pdf/electrical-performances-comparison-of-semi-and-fully-40ohrn598c.pdf

Electrical Performances Comparison of Semi and Fully Recessed Isolation Structures

Spatio-temporal datasets (STD) are generated daily. Generally, their visualization includes 2D renderings or animated visualizations that do not fit to the exploration of such complex data. In this paper, we present an alternative approach to current STD visualizations. Our approach uses tangible and visual tools such as mini-robots and a tactile interaction screen to facilitate access, interpretation and manipulation of this kind of data. While tangible elements have been introduced to represent information, our system provides a new approach to explore multidimensional datasets that conventional tools would not allow.

/pdf/a-new-approach-for-spatio-temporal-data-mining-3661bilj9z.pdf

Emmanuel Dubois

Papers

Investigation on the platinum silicide Schottky barrier height modulation using a dopant segregation approach

Low temperature tunneling current enhancement in silicide/Si Schottky contacts with nanoscale barrier width

An Original Selective Etch of Pt vs. PtSi using a Low Temperature Germanidation Process

Electrical Performances Comparison of Semi and Fully Recessed Isolation Structures

A new approach for spatio-temporal data mining