54602717
Experience with the TRIUMF Main Tank Vacuum Control System
The TRIUMF Main Tank Vacuum Control System was upgraded in 1984. The earlier system, which consisted of a collection of hardwired relay logic boxes housed in three standard instrumentation racks, was replaced with a compact and flexible microprocessor-based control system. The user interface, previously distributed over the three racks, was consolidated into a single hardwired control and mimic panel. Since 1984, the Main Tank Vacuum System has undergone a series of changes in configuration and vacuum pumping hardware with necessary changes being implemented in the control system logic. Corresponding changes to the user interface were sometimes difficult to implement and in time exhausted the spare input/output capacity which had been built in to the panel. The availability of inexpensive personal computers with adequate graphics capability and the ease of modifying, or adding to a programmable user interface precipitated the retirement of the hardwired panel and its replacement by a PC-based graphics user interface. System configuration, safety considerations, the hardware and the software implementation using the 'C' programming language are described. The evolution of the control system and its performance, both over the years and in adapting to the vacuum system changes, are discussed.<<ETX>>
61175398
VAX Q-bus to CAMAC systems crate interface for long CAMAC branches
The TRIUMF Central Control System (CCS) was to be upgraded to use Q-bus-based VAXs. The CCS consists of multiple computers interfaced to a CAMAC Executive Crate with long parallel branches containing multiple pairs of differential branch extenders (DBE). The Creative Electronics System SCI 2280 systems crate interface used for the Q-bus VAX requires the CAMAC operation to complete synchronously with the Q-bus cycle in less than the Q-bus timeout period. This translates to a maximum branch length of about 150 meters containing three pairs of DBEs, which was not adequate. A Q-bus-to-SCI 2280 interface was built to allow CAMAC cycles to be decoupled, when desired, from the Q-bus cycles. When cycles are decoupled, completion of the CAMAC part can be ascertained by testing flags in the interface. The interface design and operation are described and the results of tests using a VAX 3500 are given.<<ETX>>
107947607
RECENT DEVELOPMENTS IN THE TRIUMF CONTROL SYSTEM
The principle ideas and underlying architecture of the TRIUMF Central Control System have not changed since its commissioning in 1974. As described elsewhere 1,2,3 the system consists of a number of Data General minicomputers which communicate using a proprietary Data General parallel direct memory access interprocessor bus, and which share access to a common multiported memory containing a limited descriptive data base of device addresses and pointers to acquisition and conversion routines (Figure 1). The most important idea of the TRIUMF Control System design, and one which has in large measure determined the manner of its evolution, is the use of the executive crate, by means of which all central system computers share direct and immediate access to the entire seven parallel branch CAM.4C system, which in turn interfaces all accelerator devices and most of the main Control Room console devices. Expansion of the Control System to date has been realized on one hand by the addition of CAM.4C crates, and on the other by the addition of minicomputers to the executive crate interface. With the use of active extenders. the executive crate has been extended to three CAMAC crates. and could in principle clcctrically support as many as 1500 sources. In practice, this number is limited to a.bout 30 sources by bandwidth considerations, and to even fewer by the geographical requirement that sources be located physically within about 50 ft. (I/O bus length limitation) of the executive crate. This paper describes three recent developments in the TRIIJMF system whose designs have been influenced by its multisourced architecture. These are:
119062307
Comments on the renormalizability of the Broken Phase in Noncommutative Scalar Field Theory
We study the noncommutative 4 theory with spontaneously broken global O(2) symmetry in 4 dimensions. We demonstrate the renormalizability at one loop. This does not require any choice of ordering of the fields in the interaction terms. It involves regulating the ultraviolet and infrared divergences in a manner consistent with the Ward identities.
121582631
Dark energy, cosmic coincidence and future singularity of the universe
Dark energy model with the equation of state $$p_{DE} =-\rho _{DE} -A\rho _{DE}^\alpha $$, is characterised by four finite life time future singularity of the universe for different values of the parameter $$A$$ and $$\alpha $$ [Nojiri et al. in Phys Rev D 71:063004, 2005]. Since from the matter dominated era to the dark energy dominated era the ratio of the dark energy density to the matter energy density increases as the universe expand for these future singularities, the universe passes through a significant time when the dark energy density and the matter energy density are nearly comparable. Considering $$\frac{1}{r_0 }<r=\frac{\rho _{DE} }{\rho _M }<r_0 $$, where $$r_0$$ is any fixed ratio, we calculate the fraction of total life time of the universe when the universe passes through the coincidental stage for these singularities. It has been found that the fractional time varies as $$\alpha $$ varies within the range for which these finite life time future singularities occur and the fraction is smaller for smaller values of $$r_0 $$. Importance of the fractional time and observational limits onto the values of the parameter $$A$$ and $$\alpha $$ has also been discussed.
119541770
Local currents for a deformed algebra of quantum mechanics with a fundamental length scale
We explore some explicit representations of a certain stable deformed algebra of quantum mechanics, considered by R Vilela Mendes, having a fundamental length scale. The relation of the irreducible representations of the deformed algebra to those of the (limiting) Heisenberg algebra is discussed, and we construct the generalized harmonic oscillator Hamiltonian in this framework. To obtain local currents for this algebra, we extend the usual nonrelativistic local current algebra of vector fields and the corresponding group of diffeomorphisms, modelling the quantum configuration space as a commutative spatial manifold with one additional dimension.
59390087
A Grid job monitoring system
This paper presents a web-based Job Monitoring framework for individual Grid sites that allows users to follow in detail their jobs in quasi-real time. The framework consists of several independent components : (a) a set of sensors that run on the site CE and worker nodes and update a database, (b) a simple yet extensible web services framework and (c) an Ajax powered web interface having a look-and-feel and control similar to a desktop application. The monitoring framework supports LSF, Condor and PBS-like batch systems. This is one of the first monitoring systems where an X.509 authenticated web interface can be seamlessly accessed by both end-users and site administrators. While a site administrator has access to all the possible information, a user can only view the jobs for the Virtual Organizations (VO) he/she is a part of. The monitoring framework design supports several possible deployment scenarios. For a site running a supported batch system, the system may be deployed as a whole, or existing site sensors can be adapted and reused with the web services components. A site may even prefer to build the web server independently and choose to use only the Ajax powered web interface. Finally, the system is being used to monitor a glideinWMS instance. This broadens the scope significantly, allowing it to monitor jobs over multiple sites.
17317284
CMS Monte Carlo production in the WLCG computing Grid
Monte Carlo production in CMS has received a major boost in performance and 
scale since the past CHEP06 conference. The production system has been re-engineered in order 
to incorporate the experience gained in running the previous system and to integrate production 
with the new CMS event data model, data management system and data processing framework. 
The system is interfaced to the two major computing Grids used by CMS, the LHC Computing 
Grid (LCG) and the Open Science Grid (OSG). 
Operational experience and integration aspects of the new CMS Monte Carlo production 
system is presented together with an analysis of production statistics. The new system 
automatically handles job submission, resource monitoring, job queuing, job distribution 
according to the available resources, data merging, registration of data into the data 
bookkeeping, data location, data transfer and placement systems. Compared to the previous 
production system automation, reliability and performance have been considerably improved. A 
more efficient use of computing resources and a better handling of the inherent Grid unreliability 
have resulted in an increase of production scale by about an order of magnitude, capable of 
running in parallel at the order of ten thousand jobs and yielding more than two million events 
per day.