Spacecraft design project: High latitude communications satellite

The spacecraft design project was part of AE-4871, Advanced Spacecraft Design. The project was intended to provide experience in the design of all major components of a satellite. Each member of the class was given primary responsibility for a subsystem or design support function. Support was requested from the Naval Research Laboratory to augment the Naval Postgraduate School faculty. Analysis and design of each subsystem was done to the extent possible within the constraints of an eleven week quarter and the design facilities (hardware and software) available. The project team chose to evaluate the design of a high latitude communications satellite as representative of the design issues and tradeoffs necessary for a wide range of satellites. The High-Latitude Communications Satellite (HILACS) will provide a continuous UHF communications link between stations located north of the region covered by geosynchronous communications satellites, i.e., the area above approximately 60 N latitude. HILACS will also provide a communications link to stations below 60 N via a relay Net Control Station (NCS), which is located with access to both the HILACS and geosynchronous communications satellites. The communications payload will operate only for that portion of the orbit necessary to provide specified coverage

The new CMS DAQ system for LHC operation after 2014 (DAQ2)

The Data Acquisition system of the Compact Muon Solenoid experiment at CERN assembles events at a rate of 100 kHz, transporting event data at an aggregate throughput of 100 GByte/s. We are presenting the design of the 2nd generation DAQ system, including studies of the event builder based on advanced networking technologies such as 10 and 40 Gbit/s Ethernet and 56 Gbit/s FDR Infiniband and exploitation of multicore CPU architectures. By the time the LHC restarts after the 2013/14 shutdown, the current compute nodes, networking, and storage infrastructure will have reached the end of their lifetime. In order to handle higher LHC luminosities and event pileup, a number of sub-detectors will be upgraded, increase the number of readout channels and replace the off-detector readout electronics with a μTCA implementation. The second generation DAQ system, foreseen for 2014, will need to accommodate the readout of both existing and new off-detector electronics and provide an increased throughput capacity. Advances in storage technology could make it feasible to write the output of the event builder to (RAM or SSD) disks and implement the HLT processing entirely file based.United States. Dept. of EnergyNational Science Foundation (U.S.)Marie Curie International Fellowshi

First operational experience with the CMS Run Control System

The Run Control System of the Compact Muon Solenoid (CMS) experiment at CERN's new Large Hadron Collider (LHC) controls the sub-detector and central data acquisition systems and the high-level trigger farm of the experiment. It manages around 10,000 applications that control custom hardware or handle the event building and the high-level trigger processing. The CMS Run Control System is a distributed Java system running on a set of Apache Tomcat servlet containers. Users interact with the system through a web browser. The paper presents the architecture of the CMS Run Control System and deals with operational aspects during the first phase of operation with colliding beams. In particular it focuses on performance, stability, integration with the CMS Detector Control System, integration with LHC status information and tools to guide the shifter.United States. Dept. of EnergyNational Science Foundation (U.S.)European Community. Marie-Curie Research Network

Perspective: A Magazine for Different People

Perspective was published by undergraduate students at UND in April 1978. The lone issue featured articles about the culture and history of Sioux Indians, an interview with an African student and an African-American student, domestic abuse of women, the development of new energy resources in North Dakota, and the new Hughes Fine Arts Center. Photographs, cartoons, poetry and prose were also included.https://commons.und.edu/und-books/1065/thumbnail.jp

Measurement of the Top-Quark Mass with Dilepton Events Selected Using Neuroevolution at CDF

We report a measurement of the top-quark mass Mt in the dilepton decay channel tt̄→bl′+νl′b̄l-ν̄l. Events are selected with a neural network which has been directly optimized for statistical precision in top-quark mass using neuroevolution, a technique modeled on biological evolution. The top-quark mass is extracted from per-event probability densities that are formed by the convolution of leading order matrix elements and detector resolution functions. The joint probability is the product of the probability densities from 344 candidate events in 2.0fb-1 of pp̄ collisions collected with the CDF II detector, yielding a measurement of Mt=171.2±2.7(stat)±2.9(syst)GeV/c2

The run control and monitoring system of the CMS experiment

The CMS experiment at the LHC at CERN will start taking data in 2008. To configure, control and monitor the experiment during data-taking the Run Control and Monitoring System (RCMS) was developed. This paper describes the architecture and the technology used to implement the RCMS, as well as the deployment and commissioning strategy of this important component of the online software for the CMS experiment

Application of PC's and Linux to the CDF Run II level-3 trigger

For Run II, the CDF Level-3 trigger must provide a sustained input bandwidth of at least 45 MBytes/set and will require processing power of at least 45000 MIPS to perform the necessary reconstruction and filtering of events. We present a distributed, scalable architecture using commod- ity hardware running the Linux operating system. I/O and CPU intensive functions are separated into two types of nodes; �converter� nodes receive event fragments via ATM from Level 2 computers and distribute complete events to �processor� nodes via multiple fast ethernets. We present re- sults from a small-scale prototype roughly equivalent to a 1/16th vertical slice of the final system. With this hardware we have demonstrated the capability of sustained I/O rates of 15 MBytes/set, more then three times the required baseline performance. We discuss PC hardware and Linux software issues and modifications for real time performance

Measurement of the W boson helicity in events with a single reconstructed top quark in pp collisions at √s = 8 TeV

A measurement of the W boson helicity is presented, where the W boson originates from the decay of a top quark produced in pp collisions. The event selection, optimized for reconstructing a single top quark in the final state, requires exactly one isolated lepton (muon or electron) and exactly two jets, one of which is likely to originate from the hadronization of a bottom quark. The analysis is performed using data recorded at a center-of-mass energy of 8 TeV with the CMS detector at the CERN LHC in 2012. The data sample corresponds to an integrated luminosity of 19.7 fb[superscript −1]. The measured helicity fractions are F [subscript L] = 0.298 ± 0.028 (stat) ± 0.032(syst), F [subscript 0] = 0.720 ± 0.039 (stat) ± 0.037(syst), and F [subscript R] = −0.018 ± 0.019 (stat) ± 0.011(syst). These results are used to set limits on the real part of the tWb anomalous couplings, g [subscript L] and g [subscript R]

Search for new physics in events with same-sign dileptons and jets in pp collisions at √s = 8 TeV

A search for new physics is performed based on events with jets and a pair of isolated, same-sign leptons. The results are obtained using a sample of proton-proton collision data collected by the CMS experiment at a centre-of-mass energy of 8 TeV at the LHC, corresponding to an integrated luminosity of 19.5 fb[superscript −1]. In order to be sensitive to a wide variety of possible signals beyond the standard model, multiple search regions defined by the missing transverse energy, the hadronic energy, the number of jets and b-quark jets, and the transverse momenta of the leptons in the events are considered. No excess above the standard model background expectation is observed and constraints are set on a number of models for new physics, as well as on the same-sign top-quark pair and quadruple-top-quark production cross sections. Information on event selection efficiencies is also provided, so that the results can be used to confront an even broader class of new physics models.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio