Logical Names Research Articles

Relative rotation rates for driven dynamical systems.

Relative rotation rates for two-dimensional driven dynamical systems are defined with respect to arbitrary pairs of periodic orbits. These indices describe the average rate, per period, at which one orbit rotates around another. These quantities are topological invariants of the dynamical system, but contain more physical information than the standard topological invariants for knots, the linking and self-linking numbers, to which they are closely related. This definition can also be extended to include noisy periodic orbits and strange attractors. A table of the relative rotation rates for a dynamical system, its intertwining matrix, can be used to determine whether orbit pairs can undergo bifurcation and, if so, the order in which the bifurcations can occur. The relative rotation rates are easily computed and measured. They have been computed for a simple model, the laser with modulated parameter. By comparing these indices with those of a zero-torsion lift of a horseshoe return map, we have been able to determine that the dynamics of the laser are governed by the formation of a horseshoe. Additional stable periodic orbits, besides the principal subharmonics previously reported, are predicted by the dynamics. The two additional period-five attractors have been located with the aid of their logical sequence names, and their identification has been confirmed by computing their relative rotation rates.

SAMS - the synchronization and monitoring system for ATF data acquisition

SAMS performs much of the synchronization of the distributed data acquisition system for the Advanced Toroidal Facility (ATF). SAMS is responsible for propagating shot information and managing the data system directories and logical names. This paper describes how SAMS communicates with other processes, both within the VAX cluster that supports most of the ATF data acquisition and on VAXes that are connected to the cluster via DECnet.

CHERS software system—A microVAX-based diagnostic

The charge exchange recombination spectroscopy (CHERS) diagnostic is the first tokamak fusion test reactor (TFTR) diagnostic to utilize a microVAX II computer for device control, data acquisition, analysis, and event-driven processing. The CHERS system is controlled from a single interactive menu-driven process, enabling the diagnostic physicist to perform interactive device control and monitoring, calibration and control file editing, and to control automatic device setup, data acquisition and display, and postshot analysis. All software is written in fortran. Device control is accomplished using the (ORNL) VAX CAMAC and TAU real-time image processing system (RTIPS) fortran subroutines. Standard VAX system services are utilized, including the use of event flags, global sections, logical names, security services, process control, and spawning of subprocesses.

Nombres y predicados

Nombres y predicados

The Use of a Commercial Data Base Management System in the LAMPF Control System

The control system for the accelerator at the Los Alamos Meson Physics Facility (LAMPF) is currently being upgraded to run on a DEC VAX 11/780. To unify the several disparate control hardware protocols into one consistent software protocol requires that the hardware devices be addressed logically rather than physically, the physical connections being supplied by the control system. To accomplish this, the control system must have some link between the devices logical names and their physical connections. This link is supplied by a data base which is managed by a commercial data base management system. This paper discusses the reasoning behind the choice of a commercial system, the particular DBMS chosen and some of the pros and cons of using the DBMS as well as some of our experiences trying to join tools of the commercial world with the real-time world.

A research-oriented treatment planning program system

The function of a treatment planning program is to graphically simulate radiation dose distributions from proposed radiation therapy treatments. While many such programs are available which provide this much-needed service, none addresses the question of how to intercompare calculation and display techniques. This paper describes a program system designed for support of research efforts, particularly development and testing on new calculation algorithms. The system emphasizes a modular flexible structure, enabling programs to be developed somewhat as interchangeable parts. Thus multiple variants of a calculation algorithm can be compared without undue software overhead or additional data management. Unusual features of the system include extensive use of command procedures, logical names and a structured language (PASCAL). These features are described along with other implementation details. Obstacles, limitations and future applications are also discussed.

Tres dificultades en la teoría de las descripciones de Bertrand Russell

Resumen