20,984 research outputs found
A new CMS pixel detector for the LHC luminosity upgrade
The CMS inner pixel detector system is planned to be replaced during the
first phase of the LHC luminosity upgrade. The plans foresee an ultra low mass
system with four barrel layers and three disks on either end. With the expected
increase in particle rates, the electronic readout chain will be changed for
fast digital signals. An overview of the envisaged design options for the
upgraded CMS pixel detector is given, as well as estimates of the tracking and
vertexing performance.Comment: 5 pages, 8 figures, proceedings of 8th International Conference on
Radiation Effects on Semiconductor Materials Detectors and Device
Prototype ATLAS IBL Modules using the FE-I4A Front-End Readout Chip
The ATLAS Collaboration will upgrade its semiconductor pixel tracking
detector with a new Insertable B-layer (IBL) between the existing pixel
detector and the vacuum pipe of the Large Hadron Collider. The extreme
operating conditions at this location have necessitated the development of new
radiation hard pixel sensor technologies and a new front-end readout chip,
called the FE-I4. Planar pixel sensors and 3D pixel sensors have been
investigated to equip this new pixel layer, and prototype modules using the
FE-I4A have been fabricated and characterized using 120 GeV pions at the CERN
SPS and 4 GeV positrons at DESY, before and after module irradiation. Beam test
results are presented, including charge collection efficiency, tracking
efficiency and charge sharing.Comment: 45 pages, 30 figures, submitted to JINS
Recent trends, technical concepts and components of computer-assisted orthopedic surgery systems: A comprehensive review
Computer-assisted orthopedic surgery (CAOS) systems have become one of the most important and challenging types of system in clinical orthopedics, as they enable precise treatment of musculoskeletal diseases, employing modern clinical navigation systems and surgical tools. This paper brings a comprehensive review of recent trends and possibilities of CAOS systems. There are three types of the surgical planning systems, including: systems based on the volumetric images (computer tomography (CT), magnetic resonance imaging (MRI) or ultrasound images), further systems utilize either 2D or 3D fluoroscopic images, and the last one utilizes the kinetic information about the joints and morphological information about the target bones. This complex review is focused on three fundamental aspects of CAOS systems: their essential components, types of CAOS systems, and mechanical tools used in CAOS systems. In this review, we also outline the possibilities for using ultrasound computer-assisted orthopedic surgery (UCAOS) systems as an alternative to conventionally used CAOS systems.Web of Science1923art. no. 519
On The Possibility of Enrichment and Differentiation in Gas Giants During Birth by Disk Instability
We investigate the coupling between rock-size solids and gas during the
formation of gas giant planets by disk fragmentation in the outer regions of
massive disks. In this study, we use three-dimensional radiative hydrodynamics
simulations and model solids as a spatial distribution of particles. We assume
that half of the total solid fraction is in small grains and half in large
solids. The former are perfectly entrained with the gas and set the opacity in
the disk, while the latter are allowed to respond to gas drag forces, with the
back reaction on the gas taken into account. To explore the maximum effects of
gas-solid interactions, we first consider 10cm-size particles. We then compare
these results to a simulation with 1 km-size particles, which explores the
low-drag regime. We show that (1) disk instability planets have the potential
to form large cores due to aerodynamic capturing of rock-size solids in spiral
arms before fragmentation; (2) that temporary clumps can concentrate tens of
of solids in very localized regions before clump disruption; (3)
that the formation of permanent clumps, even in the outer disk, is dependent on
the grain-size distribution, i.e., the opacity; (4) that nonaxisymmetric
structure in the disk can create disk regions that have a solids-to-gas ratio
greater than unity; (5) that the solid distribution may affect the
fragmentation process; (6) that proto-gas giants and proto-brown dwarfs can
start as differentiated objects prior to the H collapse phase; (7) that
spiral arms in a gravitationally unstable disk are able to stop the inward
drift of rock-size solids, even redistributing them to larger radii; and, (8)
that large solids can form spiral arms that are offset from the gaseous spiral
arms. We conclude that planet embryo formation can be strongly affected by the
growth of solids during the earliest stages of disk accretion.Comment: Accepted by ApJ. 55 pages including 24 figures. In response to
comments from the referee, we have included a new simulation with km-size
objects and have revised some discussions and interpretations. Major
conclusions remain unchanged, and new conclusions have been added in response
to the new ru
Design, Fabrication, and Run-time Strategies for Hardware-Assisted Security
Today, electronic computing devices are critically involved in our daily lives, basic infrastructure, and national defense systems. With the growing number of threats against them, hardware-based security features offer the best chance for building secure and trustworthy cyber systems. In this dissertation, we investigate ways of making hardware-based security into a reality with primary focus on two areas: Hardware Trojan Detection and Physically Unclonable Functions (PUFs). Hardware Trojans are malicious modifications made to original IC designs or layouts that can jeopardize the integrity of hardware and software platforms. Since most modern systems critically depend on ICs, detection of hardware Trojans has garnered significant interest in academia, industry, as well as governmental agencies. The majority of existing detection schemes focus on test-time because of the limited hardware resources available at run-time. In this dissertation, we explore innovative run-time solutions that utilize on-chip thermal sensor measurements and fundamental estimation/detection theory to expose changes in IC power/thermal profile caused by Trojan activation. The proposed solutions are low overhead and also generalizable to many other sensing modalities and problem instances. Simulation results using state-of-the-art tools on publicly available Trojan benchmarks verify that our approaches can detect Trojans quickly and with few false positives. Physically Unclonable Functions (PUFs) are circuits that rely on IC fabrication variations to generate unique signatures for various security applications such as IC authentication, anti-counterfeiting, cryptographic key generation, and tamper resistance. While the existence of variations has been well exploited in PUF design, knowledge of exactly how variations come into existence has largely been ignored. Yet, for several decades the Design-for-Manufacturability (DFM) community has actually investigated the fundamental sources of these variations. Furthermore, since manufacturing variations are often harmful to IC yield, the existing DFM tools have been geared towards suppressing them (counter-intuitive for PUFs). In this dissertation, we make several improvements over current state-of-the-art work in PUFs. First, our approaches exploit existing DFM models to improve PUFs at physical layout and mask generation levels. Second, our proposed algorithms reverse the role of standard DFM tools and extend them towards improving PUF quality without harming non-PUF portions of the IC. Finally, since our approaches occur after design and before fabrication, they are applicable to all types of PUFs and have little overhead in terms of area, power, etc. The innovative and unconventional techniques presented in this dissertation should act as important building blocks for future work in cyber security
Product Innovation and Growth: The Case of Integrated Circuits
A puzzling evidence stemming from the applied research on growth and innovation is that successful innovations do not appear to have a significant effect on sales growth rates, at odds with the expectation that successful innovators will prosper at the expenses of their less able competitors. The present paper tests a research hypothesis claiming that the level of observation at which applied research is typically conducted hampers the identification of a significant association between innovation and sales growth rates. Exploiting a unique and original database comprising detailed information on product innovations by leading semiconductor companies, we find components commercialized in the nearest past to positively affect the stream of corporate revenues.Firm Growth; Product Innovation; Semiconductor industry
Differential temperature sensors: Review of applications in the test and characterization of circuits, usage and design methodology
Differential temperature sensors can be placed in integrated circuits to extract a signature ofthe power dissipated by the adjacent circuit blocks built in the same silicon die. This review paper firstdiscusses the singularity that differential temperature sensors provide with respect to other sensortopologies, with circuit monitoring being their main application. The paper focuses on the monitoringof radio-frequency analog circuits. The strategies to extract the power signature of the monitoredcircuit are reviewed, and a list of application examples in the domain of test and characterizationis provided. As a practical example, we elaborate the design methodology to conceive, step bystep, a differential temperature sensor to monitor the aging degradation in a class-A linear poweramplifier working in the 2.4 GHz Industrial Scientific MedicalâISMâband. It is discussed how,for this particular application, a sensor with a temperature resolution of 0.02 K and a high dynamicrange is required. A circuit solution for this objective is proposed, as well as recommendations for thedimensions and location of the devices that form the temperature sensor. The paper concludes with adescription of a simple procedure to monitor time variability.Postprint (published version
The Cleo Rich Detector
We describe the design, construction and performance of a Ring Imaging
Cherenkov Detector (RICH) constructed to identify charged particles in the CLEO
experiment. Cherenkov radiation occurs in LiF crystals, both planar and ones
with a novel ``sawtooth''-shaped exit surface. Photons in the wavelength
interval 135--165 nm are detected using multi-wire chambers filled with a
mixture of methane gas and triethylamine vapor. Excellent pion/kaon separation
is demonstrated.Comment: 75 pages, 57 figures, (updated July 26, 2005 to reflect reviewers
comments), to be published in NIM
The Boston University Photonics Center annual report 2013-2014
This repository item contains an annual report that summarizes activities of the Boston University Photonics Center in the 2013-2014 academic year. The report provides quantitative and descriptive information regarding photonics programs in education, interdisciplinary research, business innovation, and technology development. The Boston University Photonics Center (BUPC) is an interdisciplinary hub for education, research, scholarship, innovation, and technology development associated with practical uses of light.This annual report summarizes activities of the Boston University Photonics Center in the 2013â2014 academic year.This has been a good year for the Photonics Center. In the following pages, you will see that the centerâs faculty received prodigious honors and awards, generated more than 100 notable scholarly publications in the leading journals in our field, and attracted 20M in research funding for the University, are indicative of the breadth of Photonics Center research interests: from fundamental modeling of optoelectronic materials to practical development of cancer diagnostics, from exciting new discoveries in optogenetics for understanding brain function to the achievement of world-record resolution in semiconductor circuit microscopy. Our community welcomed an auspicious cohort of new faculty members, including a newly hired assistant professor and a newly hired professor (and Chair of the Mechanical Engineering Department). The Industry/University Cooperative Research Centerâthe centerpiece of our translational biophotonics programâcontinues to focus on advancing the health care and medical device industries, and has entered its fourth year of operation with a strong record of achievement and with the support of an enthusiastic industrial membership base
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