Global community

The force decomposition algorithm maps all possible interactions to processors and does not require inter-processor communication during the force calculation phase of MD simulation. However, to obtain the net force on each particle for the update phase would need global communication. In this section, we will present parallel algorithms based on force decomposition. 

TNC.51. 1. Prigogine, P. M. AUen, and R. Herman, Long term trends and the evolution of complexity, in Goals in a Global Community, Rapport Club de Rome, Vol. 1, E. Laszlo and J. Bierman, eds., Pergamon, New York, 1977, pp. 41-62. 

Petersen F. (2005) Natural products research at Novartis Pharmaceuticals — A historical overview. In Drug Discovery from Natural Products — 85 Years of Natural Products Research at Novartis, pp. 1-13. NIBR Global Communications, Cambridge, USA. 

EcoNet - Institute for Global Communications (IGC). Online. Available HTTP (accessed 1 April 2003). 

In short, this means that it may be difficult to have radio, television, and rapid global communication in higher-dimensional worlds. [For a theoretical discussion, see Morley, T. (1985) A simple proof that the world is three-dimensional. SIAM Review. 27(1) 69-71.]... 

As the impact of our advanced technologies on the global community becomes understood demands are ever increasing for chemosensors to selectively detect in real time and space a variety of biological and chemical substances at ultratrace levels. Within this context, by enabling dramatic new powers of observation,... 

It had to transform the conglomerate into a focused portfolio that gave the new company a credible story of value creation for customers, shareholders, employees, and global communities ... 

Digital communication networks are at the heart of modem society. The digitization of communications, development of the Internet, and the availability of relatively inexpensive but powerful mobile computing technologies have established a global communications network capable of linking billions of people, places, and objects. 

How do hydrocarbons benefit our society How do they affect the environment What are the benefits and risks of using hydrocarbon fuels and petrochemicals These are important questions for our global community. See Figure 14.30 for some ideas. 

Market research companies buy prescription records from pharmacies and wholesalers (and, to a lesser degree, hospitals and doctors). On every prescription, there s data about the prescription, the condition, the dosage, packet size, pharmacy, pricing, the doctor who prescribed it, explains Michael Gury, vice president of global communications for Connecticut-... 

In spatial decomposition, or geometric methods,249 tjjg physical simulation domain is subdivided into small three-dimensional boxes, one for each processor. Each processor computes forces on and updates the positions and velocities of all atoms within its box at each time step, with atoms reassigned to new processors as they move through the physical domain. Because a processor can compute forces on its atoms knowing only the positions of atoms in nearby boxes, the communication required in the spatial decomposition is local, in contrast to the global communications required in the atom and force decomposition methods. 

Atom decomposition methods are the most straightforward to implement, reflected by their usage in major simulation packages such as CHARMM and GROMOS. Yet their dependence on global communications limits the number of processors that can be effectively used. In the LJ benchmark, communication costs begin to dominate by the time hundreds of processors have been used, since there is little speed-up when the number of processors is doubled. 

Figure 9 Replicated data method using only one global communication step. Particle coordinates and velocities are replicated on aU nodes. A complete force array is also stored on each node. By integrating the whole system on each node independently the method only requires on communication step.

Which one of these variations one should use is mostly a question of the balance between communication and calculation of the parallel computer being used. In any case as the systems grow larger the RD method will be limited by the all-to-all global communication steps. However, there is an improvement of the RD method which avoids global all-to-all communication [102]. Also it is possible to combine the ideas of RD with systolic loop algorithms. The main reason to do this would be to decrease the need for node memory and it also opens up the possibility for overlapping communication and calculation [46,103-105]. 

A critical part for the functioning of IDC is the Global Communications Infrastructure (GCI). The GCI will support the transmission of raw data from the 337 facilities of the International Monitoring System (IMS) to the IDC in Vienna, and the distribution of data and IDC products to State Signatories, primarily through their national data centres (NDCs). The GCI will be the world s first, global VSAT-based satellite system, linking stations and NDCs in populated and quite remote areas of all continents and island sites. 

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