35,122 research outputs found
Intruder detection system
An intruder detection system is described. The system contains a transmitter which sends a frequency modulated and amplitude modulated signal to a remote receiver in response to a geophone detector which responds to seismic impulses created by the intruder. The signal makes it possible for an operator to determine the number of intruders and the manner of movement
Characterization of Model-Based Detectors for CPS Sensor Faults/Attacks
A vector-valued model-based cumulative sum (CUSUM) procedure is proposed for
identifying faulty/falsified sensor measurements. First, given the system
dynamics, we derive tools for tuning the CUSUM procedure in the fault/attack
free case to fulfill a desired detection performance (in terms of false alarm
rate). We use the widely-used chi-squared fault/attack detection procedure as a
benchmark to compare the performance of the CUSUM. In particular, we
characterize the state degradation that a class of attacks can induce to the
system while enforcing that the detectors (CUSUM and chi-squared) do not raise
alarms. In doing so, we find the upper bound of state degradation that is
possible by an undetected attacker. We quantify the advantage of using a
dynamic detector (CUSUM), which leverages the history of the state, over a
static detector (chi-squared) which uses a single measurement at a time.
Simulations of a chemical reactor with heat exchanger are presented to
illustrate the performance of our tools.Comment: Submitted to IEEE Transactions on Control Systems Technolog
The ATLAS Inner Detector operation, data quality and tracking performance
The ATLAS Inner Detector is responsible for particle tracking in ATLAS
experiment at CERN Large Hadron Collider (LHC) and comprises silicon and gas
based detectors. The combination of both silicon and gas based detectors
provides high precision impact parameter and momentum measurement of charged
particles, with high efficiency and small fake rate. The ID has been used to
exploit fully the physics potential of the LHC since the first proton-proton
collisions at 7 TeV were delivered in 2009. The performance of track and vertex
reconstruction is presented, as well as the operation aspects of the Inner
Detector and the data quality during the many months of data taking.Comment: Physics in Collision, Slovakia, 201
Tuning Windowed Chi-Squared Detectors for Sensor Attacks
A model-based windowed chi-squared procedure is proposed for identifying
falsified sensor measurements. We employ the widely-used static chi-squared and
the dynamic cumulative sum (CUSUM) fault/attack detection procedures as
benchmarks to compare the performance of the windowed chi-squared detector. In
particular, we characterize the state degradation that a class of attacks can
induce to the system while enforcing that the detectors do not raise alarms
(zero-alarm attacks). We quantify the advantage of using dynamic detectors
(windowed chi-squared and CUSUM detectors), which leverages the history of the
state, over a static detector (chi-squared) which uses a single measurement at
a time. Simulations using a chemical reactor are presented to illustrate the
performance of our tools
ATLAS silicon module assembly and qualification tests at IFIC Valencia
ATLAS experiment, designed to probe the interactions of particles emerging
out of proton proton collisions at energies of up to 14 TeV, will assume
operation at the Large Hadron Collider (LHC) at CERN in 2007. This paper
discusses the assembly and the quality control tests of forward detector
modules for the ATLAS silicon microstrip detector assembled at the Instituto de
Fisica Corpuscular (IFIC) in Valencia. The construction and testing procedures
are outlined and the laboratory equipment is briefly described. Emphasis is
given on the module quality achieved in terms of mechanical and electrical
stability.Comment: 23 pages, 38 EPS figures, uses JINST LaTeX clas
Characterization studies of Silicon Photomultipliers and crystals matrices for a novel time of flight PET detector
This paper describes the characterization of crystal matrices and silicon
photomultiplier arrays for a novel Positron Emission Tomography (PET) detector,
namely the external plate of the EndoTOFPET-US system. The EndoTOFPET-US
collaboration aims to integrate Time-Of-Flight PET with ultrasound endoscopy in
a novel multimodal device, capable to support the development of new biomarkers
for prostate and pancreatic tumors. The detector consists in two parts: a PET
head mounted on an ultrasound probe and an external PET plate. The challenging
goal of 1 mm spatial resolution for the PET image requires a detector with
small crystal size, and therefore high channel density: 4096 LYSO crystals
individually readout by Silicon Photomultipliers (SiPM) make up the external
plate. The quality and properties of these components must be assessed before
the assembly. The dark count rate, gain, breakdown voltage and correlated noise
of the SiPMs are measured, while the LYSO crystals are evaluated in terms of
light yield and energy resolution. In order to effectively reduce the noise in
the PET image, high time resolution for the gamma detection is mandatory. The
Coincidence Time Resolution (CTR) of all the SiPMs assembled with crystals is
measured, and results show a value close to the demanding goal of 200 ps FWHM.
The light output is evaluated for every channel for a preliminary detector
calibration, showing an average of about 1800 pixels fired on the SiPM for a
511 keV interaction. Finally, the average energy resolution at 511 keV is about
13 %, enough for effective Compton rejection.Comment: 12 pages, 31 figure
Operational experience, improvements, and performance of the CDF Run II silicon vertex detector
The Collider Detector at Fermilab (CDF) pursues a broad physics program at
Fermilab's Tevatron collider. Between Run II commissioning in early 2001 and
the end of operations in September 2011, the Tevatron delivered 12 fb-1 of
integrated luminosity of p-pbar collisions at sqrt(s)=1.96 TeV. Many physics
analyses undertaken by CDF require heavy flavor tagging with large charged
particle tracking acceptance. To realize these goals, in 2001 CDF installed
eight layers of silicon microstrip detectors around its interaction region.
These detectors were designed for 2--5 years of operation, radiation doses up
to 2 Mrad (0.02 Gy), and were expected to be replaced in 2004. The sensors were
not replaced, and the Tevatron run was extended for several years beyond its
design, exposing the sensors and electronics to much higher radiation doses
than anticipated. In this paper we describe the operational challenges
encountered over the past 10 years of running the CDF silicon detectors, the
preventive measures undertaken, and the improvements made along the way to
ensure their optimal performance for collecting high quality physics data. In
addition, we describe the quantities and methods used to monitor radiation
damage in the sensors for optimal performance and summarize the detector
performance quantities important to CDF's physics program, including vertex
resolution, heavy flavor tagging, and silicon vertex trigger performance.Comment: Preprint accepted for publication in Nuclear Instruments and Methods
A (07/31/2013
Tracking receiver Patent
Design and development of tracking receiver for tracking satellites and receiving radio signal transmissions under adverse noise condition
Fully integrated InGaAs/InP single-photon detector module with gigahertz sine wave gating
InGaAs/InP single-photon avalanche diodes (SPADs) working in the regime of
GHz clock rates are crucial components for the high-speed quantum key
distribution (QKD). We have developed for the first time a compact, stable and
user-friendly tabletop InGaAs/InP single-photon detector system operating at a
1.25 GHz gate rate that fully integrates functions for controlling and
optimizing SPAD performance. We characterize the key parameters of the detector
system and test the long-term stability of the system for continuous operation
of 75 hours. The detector system can substantially enhance QKD performance and
our present work paves the way for practical high-speed QKD applications.Comment: 11 pages, 6 figures. Accepted for publication in Review of Scientific
Instrument
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