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Issue 2 • Date Mar 1989

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Displaying Results 1 - 25 of 3857871
  • Characteristics of high-transmission-probability tunnel junctions for use as particle detectors

    Page(s): 1343 - 1346
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (368 KB)  

    Interest in the problem of the galactic dark matter has stimulated development of particle detectors sensitive to very low energies. The authors describe superconducting tunnel junctions with thin barriers which may be suitable for this purpose. They present I-V (current-voltage) characteristics and data on the temperature dependence of the subgap tunneling current. They examine the barrier transmission probability and the resistance of the null junction. They also present some scanning-electron-microscope observations of the thin films of the tunnel junctions, which show that faster deposition produces smaller grains and increasing film thickness results in larger grains from an apparent fusing of smaller grains View full abstract»

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  • C14. Robust Watermarking Scheme for Telemedicine Applications

    Page(s): 247 - 255
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    Freely Available from IEEE
  • Wireless Interrupt: Inter-Device Signaling in Next Generation Wireless Networks

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (423 KB) |  | HTML iconHTML  

    Recent advances in wireless technology have led to the proliferation of wireless devices, ranging from wireless LAN to cellular phones. There has been, and will be, an increase in not only the number of wireless services, but also the number of types of wireless services, and greater demand for mobility, portability, and integrated services. For wireless success to continue, technologies must support a high degree of flexibility and interoperability of wireless devices to scale with such demand. Next Generation Wireless will depend highly upon flexible and interoperable devices in constructing a wireless network that consists of heterogeneous devices that can communicate with each other. Our work investigates the technical issues that must be overcome in bringing such flexibility and interoperability, one of which being device discovery. We propose Wireless Interrupt, an inter-device signaling mechanism that can be employed by software defined radios, such that a device can signal its neighbors of its existence or the services it provides without knowing the protocols or channels used by its neighbors a priori. View full abstract»

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  • Phonon-mediated detection of X-rays in silicon crystals using superconducting transition edge phonon sensors

    Page(s): 1347 - 1350
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (376 KB)  

    The authors present data on the operation of thin-film superconducting strips of titanium as phonon sensors on the surface of silicon crystals. The superconducting films are biased at the foot of the resistive transition in temperature and below the critical latching current (the current above which a normal region in the film grows from self-heating). The interaction of an incident X-ray in the Si crystal generates a phonon source which propagates to the surface at the speed of sound. Such an event produces a several-microsecond-long self-terminating voltage pulse which is proportional to the amount of the sensor area driven normal. It is shown that these Ti superconducting transition edge sensors operated at 0.3 K have sufficient resolution for detecting particles with energy deposition above several keV, which makes them good candidates for use in neutrino (and other) experiments View full abstract»

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  • Kl. Comparison between Using Linear and Non-linear Features to Classify Uterine Electromyography Signals of Term and Preterm Deliveries

    Page(s): 492 - 502
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    Freely Available from IEEE
  • MOSFET-array for extracting parameters expressing SPICE-parameter variation

    Page(s): 76 - 79
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (213 KB) |  | HTML iconHTML  

    Parameters in Pelgrom's model, which express SPICE-model parameter variations, are evaluated using MOSFET array which has 16K DUTs and is made using 65-nm technology. It is found that the parameters expressing the random component of the variation are dominant, and that the parameters expressing the systematic component are mainly determined by the gate-insulator thickness. View full abstract»

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  • IVB-2 new liquid crystal electrooptic device

    Page(s): 1064
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    Freely Available from IEEE
  • Characterization of talker radiation pattern using a microphone array

    Page(s): II/257 - II/260 vol.2
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (360 KB)  

    A microphone array has the capability of capturing the properties of a significant portion of a talker's radiation pattern. In this paper, potential implications of measuring the radiation pattern of a talker for the recognition and enhancement of speech are discussed. Current applications of microphone arrays entail their installation in small enclosures such as a conference room or an automobile, typically placing a talker in the array's near field. Fitting a nominal acoustic model to a sparse sampling of the radiation pattern yields parameter estimates which should prove useful as features for speech recognition. Parameter-estimation results using fixed-radius sources (loudspeakers) are presented. Other considerations unique to placement of a talker in close proximity to an array are discussed View full abstract»

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  • Selection of basis functions for volume-surface integral equation using spanning tree

    Page(s): 2138 - 2139
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (175 KB) |  | HTML iconHTML  

    Problem of electromagnetic scattering by a system of wires, conductive surfaces and magnitodielectric volumes is solved. It is reduced to solution of volume-surface integral equations (VSIE). For approximation of equivalent electric and magnetic currents basis functions based on Rao-Wilton-Glisson (RWG) and Shaubert-Wilton-Glisson (SWG) functions are used. Integral equations are used in a form which unites formulations for different regions. To ensure linear independence of basis functions and absence of artificial charges inside volume elements the spanning tree of the graph representing topology of the mesh is constructed. Proposed method coupled with multilevel fast multipole algorithm (MLFMA) is applied to scattering on perfectly conducting sphere coated by dielectric layer. View full abstract»

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  • Electrical Characterization of Thin-Film Structures With Redeposited Sidewalls

    Page(s): 924 - 930
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (806 KB) |  | HTML iconHTML  

    Accurate electrical characterization of test structures and devices requires identification and correction for parasitic current paths in the measurement network. The sidewalls formed during reactive ion etching of thin-film phase-change material layers in argon plasma can result in parasitic current paths in the structures. In this paper, thin-film structures with redeposited sidewalls are realized, and they are experimentally characterized by electrical resistance measurements on van der Pauw test structures. The impact of conducting sidewalls on contact resistance measurements and data extraction from cross-bridge Kelvin resistor structures is discussed. The error introduced in the electrical resistance measurements from these test structures is analytically modeled. The impact on the electrical performance of devices due to the formation of sidewalls is also discussed. View full abstract»

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  • Detection of stepping stone attack under delay and chaff perturbations

    Page(s): 10 pp. - 256
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (238 KB)  

    Network based attackers often relay attacks through intermediary hosts (i.e., stepping stones) to evade detection. In addition, attackers make detection more difficult by encrypting attack traffic and introducing delay and chaff perturbations into stepping stone connections. Several approaches have been proposed to detect stepping stone attacks. However, none of them performs effectively when delay and chaff perturbations exist simultaneously. In this paper, we propose and analyze algorithms which represent that attackers cannot always evade detection only by adding limited delay and independent chaff perturbations. We provide the upper bounds on the number of packets needed to confidently detect stepping stone connections from non-stepping stone connections with any given probability of false attribution. We compare our algorithms with previous ones and the experimental results show that our algorithms are more effective in detecting stepping stone attacks in some scenarios View full abstract»

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  • Characteristics of Nb-based Josephson junctions at a temperature below 1 K

    Page(s): 1354 - 1357
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (384 KB)  

    A lithographic technique for Josephson LSI (large scale integrated) circuits was applied to the production of a superconducting tunnel junction for radiation detection. Nb-Al/aluminum oxide/Nb tunnel junctions with different junction sizes and barrier oxidation times have been fabricated. The current-voltage curves were measured in the temperature range from 4.2 to 0.45 K. The junctions showed some amounts of leakage current, which remained below 2 K. The behavior of the leakage current was successfully understood from its experimental dependence on the junction size View full abstract»

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  • Position-sensorless method for electric braking commutation of brushless DC machines

    Page(s): 701 - 713
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1451 KB)  

    To increase the cruising distance and braking reliability of various light electric vehicles (LEVs) actuated by brushless DC machines, this study proposes three cost-effective braking commutation strategies based on a general full-bridge DC/AC inverter without using position sensors. The braking commutation strategies investigated in this study are named according to the number of power switches in action over each commutation state; designated as single-switch, two-switch, and three-switch, respectively. Theoretical analysis of the operation principle and important performance indices such as maximum voltage conversion ratio, braking torque, energy recovery ratio etc, are conducted and compared among each commutation strategy. Moreover, a cost-effective, sensorless method for each different braking commutation strategy is used. The commutation signals are extracted directly from the average terminal voltages. Since additional power switches, passive components and costly position sensors are not essential, the proposed method is particularly suitable for various LEVs such as electric bicycles, electric scooters, electric wheelchairs and so on. Finally, several experiments are performed to justify the effectiveness of the proposed method. View full abstract»

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  • Session 4: Poster

    Page(s): 1
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    Freely Available from IEEE
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  • High and low-SNR regimes for stochastic networks

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (464 KB) |  | HTML iconHTML  

    A compact model for the evaluation of scaling laws in random wireless networks is proposed and studied. The model allows the information-theoretic characterization of both point-to-point as well as distributed communications. It is analyzed under several assumptions about spatial correlation and the utilized channel state information and transmission schemes. View full abstract»

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  • Message from the Cloud and Grid 2011 Organizers

    Page(s): xxx
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    Freely Available from IEEE
  • Design of Quasi-Lumped-Element Filters and Directional Couplers using Multilayer Technologies

    Page(s): 604 - 607
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2094 KB) |  | HTML iconHTML  

    The LTCC and sandwich multilayer technologies as applied to design of quasi-lumped-element passive microwave devices are considered. Design of miniature high-performance bandpass filters and directional couplers for wireless applications is presented. View full abstract»

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  • Fuzzy logic: issues, contentions and perspectives

    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (84 KB)  

    There has been a rapid growth in the number and variety of applications of fuzzy logic. The successes of fuzzy logic have also generated a skeptical reaction. Most of the criticisms directed at fuzzy logic are rooted in a misunderstanding of what it is and/or a lack of familiarity with it. In many cases, what is not recognized is that the term fuzzy logic (FL) is actually used in two different senses. In a narrow sense, fuzzy logic (FLn) is a logical system which is an extension of multivalued logic and is intended to serve as a logic of approximate reasoning. But in a wider sense, fuzzy logic (FLw) is more or less synonymous with the theory of fuzzy sets (FST). Today the term fuzzy logic is used predominantly in its wider sense. It is in this sense that any field X can be fuzzified-and hence generalized by replacing the concept of a crisp set in X by a fuzzy set. What is gained through fuzzification is greater generality, higher expressive power, an enhanced ability to model real-world phenomena and a methodology for exploiting the tolerance for imprecision. Most of the applications of fuzzy logic relate to control in the context of industrial systems and consumer products. What is discernible, however, is (a) the trend toward the use of fuzzy logic in task-oriented-rather than set-point-oriented-control; and (b) the incorporation of fuzzy logic and neural network techniques in the conception and design of complex systems in which control and expert system techniques are used in combination View full abstract»

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  • Acceleration and preconditioning strategies for higher order Moment Methods

    Page(s): 2142 - 2143
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (411 KB) |  | HTML iconHTML  

    We develop a Multilevel Fast Multipole Algorithm (MLFMA) for higher order Moment Methods that, unlike extant higher order MLFMA implementations, maintains optimal scaling independent of the patch size.We employ the new scheme to both accelerate preconditioner computation and apply it to the Generalized Method of Moments to analyze scattering from large PEC objects. View full abstract»

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  • Implementation of CAN bus device driver design base on embedded system

    Page(s): 1252 - 1255
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (370 KB) |  | HTML iconHTML  

    CAN bus (Controller Area Network), is one of the most widely used field buses of world. This article aims to explore that how to control MCP2510 CAN bus controller to send and receive data basing on s3c2440 of Samsung. In the circuit, this design adopts the MCP2510 CAN bus controller chip to expand s3c2440 interfaces, hardware contains s3c2440 chip-based development board and the MCP2510 CAN bus controller, the software mainly based on ARM Linux. This paper describes the hardware interface design, designs the CAN bus device driver base on CAN bus protocol and the characteristics of MCP2510 controller, analyses the design method which adopts driver to control the corresponding circuit. The whole system has been tested on board and meets the design goal. View full abstract»

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  • On Asynchronous Machines with Flip-Flops

    Page(s): 473
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    Freely Available from IEEE
  • Image forensics using generalised Benford's Law for accurate detection of unknown JPEG compression in watermarked images

    Page(s): 1 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1223 KB) |  | HTML iconHTML  

    In the past few years, semi-fragile watermarking has become increasingly important as it can be used to verify the content of images and to localise the tampered areas, while tolerating some non-malicious manipulations. In the literature, the majority of semi-fragile algorithms have applied a predetermined threshold to tolerate errors caused by JPEG compression. However, this predetermined threshold is typically fixed and cannot be easily adapted to different amounts of errors caused by unknown JPEG compression at different quality factors (QFs) applied to the watermarked images. In this paper, we analyse the relationship between QF and threshold, and propose the use of generalised Benford's Law as an image forensics technique for semi-fragile watermarking, to accurately detect the unknown QF of the images. The results obtained show an overall average QF correct detection rate of approximately 99% when 5% of the pixels are subjected to image content tampering, as well as compression using different QFs (ranging from 95 to 65). Consequently, our proposed image forensics method can adaptively adjust the threshold for images based on the estimated QF, therefore, improving the accuracy rates in authenticating and localising the tampered regions for semi-fragile watermarking. View full abstract»

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