Improvement of the IT-PES-PS Section Services Statistics Page

Project Specification: The IT-PES-PS service managers gather a lot of statistics for the services they run. These statistics are currently displayed by SLS (Service Level Status) or Lemon pages. They also use the Web interface provided with OpenTSDB, a DB optimised for time series. And while these various pages give very useful and technical information, they do not always emphasise the important figures. Having different statistics pages makes it difficult to see the relevant numbers at once. The goal of this project was to build homogeneous dashboards with interactive plots to better reflect the activity and resources of each service, showing relevant figures at first sight in a single website. Abstract: There is a need in the IT-PES-PS section to improve the current situation of having to consult the relevant information from several heterogeneous websites by introducing interactive homogeneous dashboards, accessible from a single web application where the information needed can be quickly accessed. The goal of this openlab Summer Student project was to create a website with homogeneous and interactive dashboards. Its architecture had to allow the creation of new dashboards easily

Preliminary weight and costs of sandwich panels to distribute concentrated loads

Minimum mass honeycomb sandwich panels were sized for transmitting a concentrated load to a uniform reaction through various distances. The form skin gages were fully stressed with a finite element computer code. The panel general stability was evaluated with a buckling computer code labeled STAGS-B. Two skin materials were considered; aluminum and graphite-epoxy. The core was constant thickness aluminum honeycomb. Various panel sizes and load levels were considered. The computer generated data were generalized to allow preliminary least mass panel designs for a wide range of panel sizes and load intensities. An assessment of panel fabrication cost was also conducted. Various comparisons between panel mass, panel size, panel loading, and panel cost are presented in both tabular and graphical form

From analog to digital

Analog-to-digital conversion and its reverse, digital-to-analog conversion, are ubiquitous in all modern electronics, from instrumentation and telecommunication equipment to computers and entertainment. We shall explore the consequences of converting signals between the analog and digital domains and give an overview of the internal architecture and operation of a number of converter types. The importance of analog input and clock signal integrity will be explained and methods to prevent or mitigate the effects of interference will be shown. Examples will be drawn from several manufacturers' datasheets

High Performance Direct Gravitational N-body Simulations on Graphics Processing Units

We present the results of gravitational direct $N$-body simulations using the commercial graphics processing units (GPU) NVIDIA Quadro FX1400 and GeForce 8800GTX, and compare the results with GRAPE-6Af special purpose hardware. The force evaluation of the $N$-body problem was implemented in Cg using the GPU directly to speed-up the calculations. The integration of the equations of motions were, running on the host computer, implemented in C using the 4th order predictor-corrector Hermite integrator with block time steps. We find that for a large number of particles (N \apgt 10^4) modern graphics processing units offer an attractive low cost alternative to GRAPE special purpose hardware. A modern GPU continues to give a relatively flat scaling with the number of particles, comparable to that of the GRAPE. Using the same time step criterion the total energy of the $N$-body system was conserved better than to one in $10^6$ on the GPU, which is only about an order of magnitude worse than obtained with GRAPE. For N\apgt 10^6 the GeForce 8800GTX was about 20 times faster than the host computer. Though still about an order of magnitude slower than GRAPE, modern GPU's outperform GRAPE in their low cost, long mean time between failure and the much larger onboard memory; the GRAPE-6Af holds at most 256k particles whereas the GeForce 8800GTF can hold 9 million particles in memory.Comment: Submitted to New Astronom

Analog electronics for beam instrumentation

The task of analog front-end electronics in beam instrumentation is to optimize the useful information content of the signal delivered by an instrument. It must suppress signal components that do not contribute to the measured quantity. It must filter to put bounds on bandwidth and possibly dynamic range, to relax the demands made of subsequent processing stages. It must minimize noise, reject interference and match the signal to transmission media and digital acquisition equipment. Since the circuitry must often operate in radio-active areas, the accent is on passive electronics.Comment: 27 pages, 60 figure

Parallel Algorithm for Solving Kepler's Equation on Graphics Processing Units: Application to Analysis of Doppler Exoplanet Searches

[Abridged] We present the results of a highly parallel Kepler equation solver using the Graphics Processing Unit (GPU) on a commercial nVidia GeForce 280GTX and the "Compute Unified Device Architecture" programming environment. We apply this to evaluate a goodness-of-fit statistic (e.g., chi^2) for Doppler observations of stars potentially harboring multiple planetary companions (assuming negligible planet-planet interactions). We tested multiple implementations using single precision, double precision, pairs of single precision, and mixed precision arithmetic. We find that the vast majority of computations can be performed using single precision arithmetic, with selective use of compensated summation for increased precision. However, standard single precision is not adequate for calculating the mean anomaly from the time of observation and orbital period when evaluating the goodness-of-fit for real planetary systems and observational data sets. Using all double precision, our GPU code outperforms a similar code using a modern CPU by a factor of over 60. Using mixed-precision, our GPU code provides a speed-up factor of over 600, when evaluating N_sys > 1024 models planetary systems each containing N_pl = 4 planets and assuming N_obs = 256 observations of each system. We conclude that modern GPUs also offer a powerful tool for repeatedly evaluating Kepler's equation and a goodness-of-fit statistic for orbital models when presented with a large parameter space.Comment: 19 pages, to appear in New Astronom

Control server for the PS orbit acquisition system Status 2009

CERN’s Proton Synchrotron (CPS) has been fitted with a new Trajectory Measurement System (TMS). Analogue signals from forty Beam Position Monitors (BPM) are digitized at 125 MS/s, and then further treated in the digital domain to derive positions of all individual particle bunches on the fly. Large FPGAs are used to handle the digital processing. The system fits in fourteen plug-in modules distributed over three half-width cPCI crates that store data in circular buffers. They are connected to a Linux computer by means of a private Gigabit Ethernet segment. Dedicated server software, running under Linux, knits the system into a coherent whole [1]. The corresponding low-level software using FESA (BPMOPS class) was implemented while respecting the standard interface for beam position measurements. The BPMOPS server publishes values on request after data extraction and conversion from the TMS server. This software is running on a VME Lynx-OS platform and through dedicated electronics it can therefore control the pickup sensitivities also making it a complete system. APIs for hardware experts are also available in order to either calibrate the system or to adjust the different TMS settings needed for each cycle. Running this system in operational mode has already given very good results compared to the old CODD system and some of them will be presented in this documen

Digital Beam Trajectory and Orbit System, for the CERN Proton Synchrotron

A new trajectory and orbit measurement system using fast signal sampling and digital signal processing in an FPGA is proposed for the CERN PS. The system uses a constant sampling frequency while the beam revolution frequency changes during acceleration. Synchronization with the beam is accomplished through a numerical PLL algorithm. This algorithm is also capable of treating RF gymnastics like bunch splitting or batch compression with the help of external timing signals. Baseline and position calculation are provided in the FPGA code as well. After having implemented the algorithms in C and MatLab and tested them with data from a test run at the PS, they have now been implemented in the FPGA for online use. Results of measurements on a single beam position monitor in the CERN PS and the SIS-18 at GSI will be presented

VME-based remote instrument control without ground loops

New electronics has been developed for the remote control of the pick-up electrodes at the CERN Proton Synchrotron (PS). Communication between VME-based control computers and remote equipment is via full duplex point-to-point digital data links. Data are sent and received in serial format over simple twisted pairs at a rate of 1 Mbit/s, for distances of up to 300 m. Coupling transformers are used to avoid ground loops. The link hardware consists of a general-purpose VME-module, the 'TRX' (transceiver), containing four FIFO-buffered communication channels, and a dedicated control card for each remote station. Remote transceiver electronics is simple enough not to require micro-controllers or processors. Currently, some sixty pick-up stations of various types, all over the PS Complex (accelerators and associated beam transfer lines) are equipped with the new system. Even though the TRX was designed primarily for communication with pick-up electronics, it could also be used for other purposes, for example to form a local area network

Strategies Small Business Owners Use to Access Working Capital to Fund Operations

Many small business owners encounter a lack of access to traditional bank funding that limits the owner’s ability to meet working capital shortages to sustain operations. Grounded in the resource-based view, the purpose of this qualitative multiple case study was to explore strategies that small, home health care agency owners use to access working capital lending sources to finance their operations. The participants comprised 3 owners of small home health agencies in Wayne County, Macomb County, and St. Clair County, Michigan, who developed and implemented successful strategies to obtain working capital. Data were collected through semistructured interviews using open-ended questions, and direct observation of financial documents. Data were analyzed using Yin’s 5-step process. Thematic analysis was used to analyze the data. Three themes emerged: alternative sources of working capital, the use of banking relationships to improve the working capital position, and the sustainability of the business. A key recommendation is that bank owners use alternative forms of working capital to sustain operations in lieu of traditional bank loans. The implications for positive social change include the potential for small business owners to increase job opportunities for residents that can create positive economic viability in the three counties