175,153 research outputs found
The CMS Silicon Strip Tracker: System Tests and Test Beam Results
With a total area of 210 squaremeters and about 15000 single silicon modules
the silicon strip tracker of the CMS experiment at the LHC will be the largest
silicon strip detector ever built. While the performance of the individual
mechanical and electronic components has already been tested extensively, their
interplay in larger integrated substructures also has to be studied before mass
production can be launched, in order to ensure the envisaged performance of the
overall system. This is the main purpose of the system tests, during which
hardware components as final as possible are being integrated into
substructures of the tracker subsystems. System tests are currently being
carried out for all subsystems of the tracker. In addition, silicon modules and
electronic components have been operated and studied in a particle beam
environment. In this report results from the CMS silicon tracker system tests
and a test beam experiment at CERN are presented.Comment: 5 pages; presented at the 8th ICATPP Conference, Como, Italy, October
6-10, 2003; to be published by World Scientifi
GLAST Tracker
The Large Area Telescope (LAT) on board the Gamma-ray Large-Area Space
Telescope (GLAST) is a pair-conversion gamma-ray detector designed to explore
the gamma-ray universe in the 20 MeV-300 GeV energy band. The Tracker subsystem
of the LAT will perform tracking of electron and positrons to determine the
origin of the gamma-ray. The design and performance of the GLAST LAT Tracker
are described in this paper.Comment: 5 pages, 5 figues, Invited talk at Vertex 2005, Chuzenji Lake, Nikko,
Japan, November 7-November 11, 2005, To be published in Nuclear Instruments
and Methods
Feasibility of Using a Commercial Fitness Tracker as an Adjunct to Family-Based Weight Management Treatment: Pilot Randomized Trial.
BACKGROUND: Fitness trackers can engage users through automated self-monitoring of physical activity. Studies evaluating the utility of fitness trackers are limited among adolescents, who are often difficult to engage in weight management treatment and are heavy technology users.
OBJECTIVE: We conducted a pilot randomized trial to describe the impact of providing adolescents and caregivers with fitness trackers as an adjunct to treatment in a tertiary care weight management clinic on adolescent fitness tracker satisfaction, fitness tracker utilization patterns, and physical activity levels.
METHODS: Adolescents were randomized to 1 of 2 groups (adolescent or dyad) at their initial weight management clinic visit. Adolescents received a fitness tracker and counseling around activity data in addition to standard treatment. A caregiver of adolescents in the dyad group also received a fitness tracker. Satisfaction with the fitness tracker, fitness tracker utilization patterns, and physical activity patterns were evaluated over 3 months.
RESULTS: A total of 88 adolescents were enrolled, with 69% (61/88) being female, 36% (32/88) black, 23% (20/88) Hispanic, and 63% (55/88) with severe obesity. Most adolescents reported that the fitness tracker was helping them meet their healthy lifestyle goals (69%) and be more motivated to achieve a healthy weight (66%). Despite this, 68% discontinued use of the fitness tracker by the end of the study. There were no significant differences between the adolescent and the dyad group in outcomes, but adolescents in the dyad group were 12.2 times more likely to discontinue using their fitness tracker if their caregiver also discontinued use of their fitness tracker (95% CI 2.4-61.6). Compared with adolescents who discontinued use of the fitness tracker during the study, adolescents who continued to use the fitness tracker recorded a higher number of daily steps in months 2 and 3 of the study (mean 5760 vs 4148 in month 2, P=.005, and mean 5942 vs 3487 in month 3, P=.002).
CONCLUSIONS: Despite high levels of satisfaction with the fitness trackers, fitness tracker discontinuation rates were high, especially among adolescents whose caregivers also discontinued use of their fitness tracker. More studies are needed to determine how to sustain the use of fitness trackers among adolescents with obesity and engage caregivers in adolescent weight management interventions
A Sliding Mode Control for a Sensorless Tracker: Application on a Photovoltaic System
The photovoltaic sun tracker allows us to increase the energy production. The
sun tracker considered in this study has two degrees of freedom (2-DOF) and
especially specified by the lack of sensors. In this way, the tracker will have
as a set point the sun position at every second during the day for a period of
five years. After sunset, the tracker goes back to the initial position (which
of sunrise). The sliding mode control (SMC) will be applied to ensure at best
the tracking mechanism and, in another hand, the sliding mode observer will
replace the velocity sensor which suffers from a lot of measurement
disturbances. Experimental measurements show that this autonomic dual axis Sun
Tracker increases the power production by over 40%
Robust Mobile Object Tracking Based on Multiple Feature Similarity and Trajectory Filtering
This paper presents a new algorithm to track mobile objects in different
scene conditions. The main idea of the proposed tracker includes estimation,
multi-features similarity measures and trajectory filtering. A feature set
(distance, area, shape ratio, color histogram) is defined for each tracked
object to search for the best matching object. Its best matching object and its
state estimated by the Kalman filter are combined to update position and size
of the tracked object. However, the mobile object trajectories are usually
fragmented because of occlusions and misdetections. Therefore, we also propose
a trajectory filtering, named global tracker, aims at removing the noisy
trajectories and fusing the fragmented trajectories belonging to a same mobile
object. The method has been tested with five videos of different scene
conditions. Three of them are provided by the ETISEO benchmarking project
(http://www-sop.inria.fr/orion/ETISEO) in which the proposed tracker
performance has been compared with other seven tracking algorithms. The
advantages of our approach over the existing state of the art ones are: (i) no
prior knowledge information is required (e.g. no calibration and no contextual
models are needed), (ii) the tracker is more reliable by combining multiple
feature similarities, (iii) the tracker can perform in different scene
conditions: single/several mobile objects, weak/strong illumination,
indoor/outdoor scenes, (iv) a trajectory filtering is defined and applied to
improve the tracker performance, (v) the tracker performance outperforms many
algorithms of the state of the art
The Genesis of Cosmological Tracker Fields
The role of the quintessence field as a probable candidate for the repulsive
dark energy, the conditions for tracking and the requisites for tracker fields
are examined. The concept of `integrated tracking' is introduced and a new
criterion for the existence of tracker potentials is derived assuming monotonic
increase in the scalar energy density parameter \Omega_\phi with the evolution
of the universe as suggested by the astrophysical constraints. It provides a
technique to investigate generic potentials of the tracker fields. The general
properties of the tracker fields are discussed and their behaviour with respect
to tracking parameter \epsilon is analyzed. It is shown that the tracker fields
around the limiting value \epsilon \simeq \frac 23 give the best fit with the
observational constraints.Comment: 8 pages, Latex file, 1 figure, comments adde
The Construction of the CMS Silicon Strip Tracker
The CMS Silicon Strip tracker is a very large scale tracker entirely based on
silicon strip detectors technology. The integration of modules, electronics,
mechanics and services has been completed within the last eighteen months;
first large standalone sub-structures (shells, disks, rods, petals depending on
the tracker subdetector) have been integrated and verified; then they have been
brought together into the final configuration. The CMS silicon tracker design
and its construction is reviewed with particular emphasis on the procedures and
quality checks deployed to successfully assembly several silicon strip modules
and all ancillary components into these large sub-structures. An overview of
the results and the lesson learned from the tracker integration are given, also
in terms of failure and damage rates.Comment: 2 pages, 5 figures, submitted to Hadron Collider Physics Symposium
2007 - La Biodola (Elba) May 200
Search for Tracker Potentials in Quintessence Theory
We report a significant finding in Quintessence theory that the the scalar
fields with tracker potentials have a model-independent scaling behaviour in
the expanding universe. So far widely discussed exponential,power law or
hyperbolic potentials can simply mimic the tracking behaviour over a limited
range of redshift. In the small redshift range where the variation of the
tracking parameter may be taken to be negligible, the differential
equation of generic potentials leads to hyperbolic sine and hyperbolic cosine
potentials which may approximate tracker field in the present day universe. We
have plotted the variation of tracker potential and the equation of state of
the tracker field as function of the redshift for the model-independent
relation derived from tracker field theory; we have also plotted the variation
of in terms of the scalar field for the chosen hyperbolic
cosine function and have compared with the curves obtained by reconstruction of
from the real observational data from the supernovae.Comment: 11 pages, 3 figures, late
Sending Jobs Overseas: The Cost to America’s Economy and Working Families
[Excerpt] This report was created by Working America and the AFL-CIO as a companion piece to WorkÂing America’s Job Tracker, a ZIP code –searchable database of jobs exported (as well as Occupational Safety and Health Act violations and other workÂplace issues). Users can search their area for comÂpanies that have sent jobs overseas. Though Job Tracker is one of the largest publicly available, fully searchable records of the extent and specifics of outsourcing, it only reveals the tip of the iceberg. This report and Job Tracker contextualize each other—Job Tracker by mapping specific job losses due to outsourcing, the report by taking a broad view of the national-level numbers that are availÂable and offering case studies of key industries
- …