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This IEEE Publication is an Open Access only journal. Open Access provides unrestricted online access to peer-reviewed journal articles.

Date 16-22 Oct. 2004

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Displaying Results 1 - 25 of 3630276
  • The NEC dependence of different scintillators for positron emission tomography

    Publication Year: 2004 , Page(s): 3785 - 3788 Vol. 6
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (699 KB) |  | HTML iconHTML  

    In positron emission tomography (PET), the concept of noise equivalent count rate (NEC) is a measure of image quality. It has been shown that the local signal-to-noise ratio in the images reflects the global signal-to-noise ratio, which, in turn, can be related to the NEC. Factors that affect the NEC include the scanner geometry and scintillator material. The peak NEC has long been considered an indicator of PET scanner performance, whereas the sensitivity, represented by the slope of the NEC curve at the origin is equally important. This initial slope is proportional to the true coincidence sensitivity times the factor (1-SF), where SF is the scatter fraction. The peak NEC value is a strong function of scanner geometry and scintillator material, scatter fraction, system dead time and random coincidence fraction. The scatter fraction depends mainly on the low level discriminator setting of the system. Access to time-of-flight information may have a strong impact on the signal-to-noise properties and hence on the NEC performance. However, this work will focus specifically on the effect of the scintillator properties on the NEC, in particular the stopping power, light output, decay time and the interaction with the electronics. Three scintillators have been compared, the standard BGO, the fast high density LSO and a new fast, high light yield scintillator LaBr3. The scintillators have been compared for the fixed scanner geometry of the ECAT EXACT. View full abstract»

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  • Optimal placement of multiple 802.11B APS in a wireless classroom

    Publication Year: 2003 , Page(s): 741 - 744 vol.2
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (297 KB) |  | HTML iconHTML  

    With the development of wireless network and stream media technology, e-learning will be used in a wireless environment wider and wider. In order to make the electronic classroom work well, the wireless network should be setup and tuned. As we know, the performance of a WLAN has been affected heavily by the distance and placement of wireless equipment. In Tianjin University, the wireless classroom has been used. This paper presents the network topology and the performance tuning and optimum. According to the simulation results, we get the optimum placement of multiple 802. 11b AP. We also build one small WLAN classroom and evaluate the performance through measuring, and our simulation result is close to the measure result. View full abstract»

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  • Vector rank m-type K-nearest neighbor filters for multichannel image processing

    Publication Year: 2004 , Page(s): 147 - 150
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (313 KB) |  | HTML iconHTML  

    First Page of the Article
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  • Automated system for the analysis of heart monophasic action potentials

    Publication Year: 2003 , Page(s): 339 - 342
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1386 KB) |  | HTML iconHTML  

    In this paper we present an automated system, which can be used in real time for the analysis of heart monophasic action potentials (MAPs) in order to analyze the behaviour of the myocardium under pathological or normal conditions. The system can be described as a three-stage procedure. In the first stage MAPs are acquired using epicardiac electrodes or MAP Franz catheters and the noise is removed using a combination of notch and band pass filters. In the second stage several features of the signal are extracted. In the third stage statistical analysis is performed. The obtained results can be used for the assessment of the electrophysiological status of the atrial muscle, ventricular muscle, and the evaluation of the effects of antiarrhythmic drugs. The validation of the system indicated that it can provide with reliable information on the myocardium condition. View full abstract»

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  • Analysis and design of 5GHz phase locked loops

    Publication Year: 2004 , Page(s): 1488 - 1491 vol.2
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (173 KB) |  | HTML iconHTML  

    Phase locked loop analysis using discrete z-domain transfer functions is presented. An impulse invariance method that produces the same z-domain equations as that of the differential analysis is first shown for a second order loop. The condition is obtained. Then a closed form third order loop equation in discrete z-domain is derived. A 3rd order 5GHz phase lock loop used for a 10 giga-bit transceiver is designed based on the discrete z-domain model and analysis. Jitter transfer of the PLL is measured, and compared with the predicted jitter transfer curve, with less than 0.1dB of peaking in the pass band. Random jitter measurement is also shown, together with silicon micrograph. View full abstract»

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  • Navigating towards the future: transitioning from terrestrial radio navigation to satellite navigation and airborne surveillance

    Publication Year: 2006 , Page(s): 17 - 21
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (334 KB)  

    This paper presents a proposal for transitioning from terrestrial-based navigation aids to implementing satellite and airborne surveillance as the primary navigation means. The transition occurs through several steps. First, the installation and use of modern navigation and surveillance equipment is mandated by the regulatory organizations. The installations should take place in a sequenced fashion to allow time for companies to absorb the initial cost. Next, the existing network of terrestrial navigation aids is down-sized leaving only the areas of heaviest use in service. At this point, the global positioning system (GPS) will be deemed the primary method of terrestrial and oceanic travel. Finally, terrestrial navigation stations will be available around airports and the remaining stations will be put in a standby condition for use in the event of a national emergency. This paper will discuss the security benefits and examples of cost savings through implementation of these steps. View full abstract»

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  • A novel hierarchical network-layer mobility management scheme based on domain-discovery for future mobile Internet

    Publication Year: 2003 , Page(s): 745 - 748 vol.2
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (326 KB) |  | HTML iconHTML  

    This paper presents the architecture and junction model of IP-based network-layer mobility management for the convergence of heterogeneous wireless network and next generation mobile Internet, and provides a framework of hierarchical network-layer mobility management based on domain-discovery scheme Also it gives a handoff strength measurement algorithm and a domain reorganizing scheme, regarding the asymmetry characteristics of the network services. The simulation result shows that flexible domain reorganizing scheme can obviously reduce the signaling cost and improve the traffic quality of the mobile terminal. View full abstract»

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  • Lane finding using homogeneous groups of cooperating autonomous vehicles

    Publication Year: 2004 , Page(s): 26 - 31
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2171 KB) |  | HTML iconHTML  

    This paper describes the problem of finding a clear lane through a potentially mined region. Using a group of cooperating AUVs, we propose several solutions and compare their advantages and disadvantages. The goal is to find straight paths clear of obstacles from one edge of a rectangular search area to the other. Homogeneous robots are used to find paths clear of all obstacles. The number of robots, their communications abilities and their sensory abilities are varied. The interleaved method shows the effectiveness of a team of interleaved robots working their way across the region. In this approach, the robots start in neighboring swaths and as they find blocked swaths (blocked by either a mine or-an obstacle) they break off and move to a new swath. This approach uses the least shared information and results in long search times that decrease predictably with the number of robots used and with the width of the sensor swath. The regional method takes a different approach, where each robot is assigned a single territory within the search area. There is little cooperation between robots; one robot would only change its path if information from its neighbor indicates the possible presence of a clear lane in a new area within its region. Search times using this approach tend to be long, and cooperation rarely shortens the search time. Preliminary results show that this cooperative approach can substantially increase the time necessary to survey the region if there are partial lanes at region boundaries. However, the regional simulation also shows a substantial decrease in the amount of time it takes to determine whether or not clear lanes are possible, compared to the interleaved approach. In the hybrid method the search area is divided into smaller regions, defined as a specific number of swaths. The robots are initially assigned to neighboring regions, and as a region is invalidated or completed, the affected robot would move to the next unassigned region. This approach forms a bridge, with the interleaved approach at one extreme (one swath per region) and the regional approach at the other (total number of swaths/number of robots per region). All three approaches were simulated in ALWSE MATLAB. The hybrid approach was also implemented in autonomous gr- ound vehicles as a physical simulation before implementation in target (amphibious) hardware. View full abstract»

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  • A 128 channel 7.5 MHz linear array ultrasonic probe using PMN-PT single crystal

    Publication Year: 2003 , Page(s): 782 - 785 Vol.1
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (275 KB) |  | HTML iconHTML  

    The performance of 128channel 7.5 MHz linear array ultrasonic probe using 0.67Pb(Mg13/ Nb23/)O3-0.33PbTiO3 single crystal was investigated. The fabrication process was modified as the mechanical and electrical properties difference between PMN-PT single crystal and conventional PZT. The sensitivity of the PMN-PT single crystal probe is about 3 dB higher than that of the conventional PZT probe, and the -6 dB bandwidth is about 30 % broader. The sensitivity variation of PMN-PT probe was similar with PZT probe. View full abstract»

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  • Power transmission and distribution system laboratories at Drexel University

    Publication Year: 2005 , Page(s): 1198 - 1205 Vol. 2
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1897 KB) |  | HTML iconHTML  

    At Drexel University, two power laboratories have been developed: the transmission oriented interconnected power system laboratory (IPSL) and, more recently, the distribution oriented reconfigurable distribution automation and control laboratory (RDAC). The laboratories provide students with hands-on experience on the analysis, operation, and planning of both transmission and distribution systems. This paper discusses power and measurement hardware in both laboratories as well as an energy management system (EMS) for IPSL and a distribution management system (DMS) for RDAC. It also addresses the successful implementation of the laboratories to undergraduate and graduate curricula at Drexel. View full abstract»

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  • An approach to extracting the target text line from a document image captured by a pen scanner

    Publication Year: 2003 , Page(s): 76 - 80 vol.1
    Cited by:  Papers (4)  |  Patents (33)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (356 KB) |  | HTML iconHTML  

    In this paper, we present a new approach to extracting the target text line from a document image captured by a pen scanner. Given the binary image, a set of possible text lines are first formed by nearest-neighbor grouping of connected components (CC). They are then refined by text line merging and adding the missed CCs. The possible target text line is identified by using a geometric feature based score function and fed to an OCR engine for character recognition. If the recognition result is confident enough, the target text line is accepted. Otherwise, all the remaining text lines are fed to the OCR engine to verify whether an alternative target text line exists or the whole image should be rejected. The effectiveness of the above approach is confirmed by experiments on a testing database consisting of 117 document images captured by C-Pen and ScanEye pen scanners. View full abstract»

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  • HySMID: an ischemia diagnosis system using genetic algorithms and multicriteria decision analysis

    Publication Year: 2003 , Page(s): 343 - 346
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1438 KB) |  | HTML iconHTML  

    Multicriteria decision analysis is employed in a four-stage (preprocessing, beat classification, window characterization and episode definition) ischemia diagnosis system, named HySMID. Beat classification is realized using a multicriteria approach where each beat is compared to already classified category prototypes and the similarity is computed in a fuzzy way. The comparison is based upon five criteria that include ST segment changes, T wave alterations and patient's age. The difficulty in applying these criteria is the determination of the required parameter values (thresholds and weights). To overcome it, a genetic algorithm is used, which after proper training, automatically calculates the optimum values of the above parameters. HySMID was validated using the European Society of Cardiology ST-T database and performed better than previously reported methods. View full abstract»

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  • Power transformer PD sources determination using current signals waveshape and pattern distributions

    Publication Year: 2004 , Page(s): 178 - 181
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (615 KB) |  | HTML iconHTML  

    An experimental investigation into the behaviour of partial discharges (PD) in three different types of defect PD models was carried out to study the characterization features. They include corona and discharge along the outer and inner surface of transformers bushing. The signals were collected by a wideband (WB) PD measurement system. Analyses of the signals indicate that the type of PD source can be determined using the signals shape and the PD pattern. View full abstract»

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  • The transformer characteristic resistance and its application to the performance analysis of silicon integrated transformers

    Publication Year: 2005 , Page(s): 597 - 600
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (239 KB) |  | HTML iconHTML  

    In this paper a novel figure of merit for the rating of integrated transformers is presented. The proposed parameter provides a more reliable performance characterization compared to previously reported ones (i.e., insertion loss and maximum available gain), since it is inherently related to the maximization of the available output power in tuned-load RF circuits. The new figure of merit is used to evaluate the effect of different substrate management approaches on the performance of silicon integrated transformers. View full abstract»

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  • Reed-Muller universal logic module networks

    Publication Year: 1993 , Page(s): 105 - 108
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (220 KB)  

    Describes Reed-Muller universal logic modules (RM-ULMs) and their use for the implementation of logic functions given in Reed-Muller (RM) form. A programmed algorithm is presented for the synthesis and optimisation of RM-ULM networks. The level-by-level minimisation procedure is based on the selection of control variables at different levels with the aim of maximising the number of discontinued branches and hence minimising the number of modules required to implement a given function. The algorithm is programmed in Fortran and can be used to realise fixed-polarity generalised Reed-Muller (GRM) expansions of any polarity and any number of variables. View full abstract»

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  • A real time spectral subtraction based speech enhancement scheme

    Publication Year: 2003 , Page(s): 1071 - 1074 vol.2
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (327 KB) |  | HTML iconHTML  

    Various speech enhancement schemes are analyzed in terms of the conflicting real time requirements of computational delay, robustness and accuracy. A spectral subtraction scheme is found to be implementable in real time using the available digital processing board. The tasks such as the computation of the spectral contents of the speech plus noise and the noise, smoothing the estimates, and speech enhancement filtering are implemented in the frequency domain using FFT in view of the computational speed and robustness. A variant of a spectral subtraction scheme is implemented in real time on a DSP board and its performance is evaluated. View full abstract»

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  • COLREGS-based navigation of autonomous marine vehicles

    Publication Year: 2004 , Page(s): 32 - 39
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2293 KB) |  | HTML iconHTML  

    This paper addresses the issue of autonomous control and safe navigation in an unmanned marine vehicle. Primarily it is concerned with the issue of effective collision avoidance. The first part of the paper examines known legal issues regarding autonomous marine vehicles, and the second part addresses how to provide an autonomous COLREGS capability in an autonomous marine vehicle. View full abstract»

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  • NEXRAD data quality by spectral processing. Spectral processing on NCAR's S-Pol radar

    Publication Year: 2003 , Page(s): 2341 - 2343 vol.4
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1364 KB) |  | HTML iconHTML  

    The WSR-88D radar system (NEXRAD) is developing a phase coded pulsing scheme using spectral processing that will improve data quality by removing overlaid echo contamination. A prototype spectral processor has been implemented on NCAR's S-Pol research radar for validation testing. Spectral processing will simultaneously enhance the anomalous propagation clutter mitigation technique, which uses a fuzzy logic based radar echo classifier, and allow future data quality enhancements. View full abstract»

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  • High performance architecture for the lifting-based DWT used in JPEG2000

    Publication Year: 2003 , Page(s): 946 - 949 Vol.2
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (334 KB)  

    High performance architecture for the lifting-based DWT (discrete wavelet transform) is introduced. It has the flexible configuration and high processing speed. The architecture includes the basic control module (BCM), the address generation unit (AGU), one-dimensional wavelet-processing element (WPE) and memory units (MUs). Because of the employ of the pipelining, the whole system is able to achieve to the higher processing speed. Additionally, power consumption and memory requirements can be reduced due to the use of the embedded data extension. The estimated gates are 6600 and the estimated frequency is 300 MHz in the SMIC 0.18μm technology. View full abstract»

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  • Tool set implementation for scenario-based multithreading of UML-RT models and experimental validation

    Publication Year: 2003 , Page(s): 70 - 77
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (299 KB) |  | HTML iconHTML  

    This paper presents our tool set implementation for scenario-based multithreading of object-oriented real-time models and an accompanying experimental validation. Our tools enable the automated, schedulability-aware implementation of real-time object-oriented models, exploiting an existing CASE tool. Our implementation is facilitated by (1) our customized runtime system modified to support scenario-based thread execution, (2) a design model template that centralizes the arrival of external inputs, (3) a model analyzer tool, and (4) a model-specific code modifier tool. Our tools simplify design by removing thread-related design concerns from the modeling process, separating design and implementation. We performed validation by conducting experiments that clearly demonstrate the performance improvements that can be gained through our scenario-based implementation: response time improvements for high priority tasks of as much as 70% and a 5-fold decrease in blocking or the elimination of blocking for some tasks. View full abstract»

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  • Application of the discrete Haar wavelet transform to image fusion for nighttime driving

    Publication Year: 2005 , Page(s): 273 - 277
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (403 KB) |  | HTML iconHTML  

    Infrared images can often provide information missing in visible images in a night driving system, but infrared images lack key features needed to operate a vehicle. Image fusion techniques can be used to combine the relevant information from both the visible and infrared images. The need for high frame rates in an automotive application motivates the investigation into computationally simple methods of combining the visible and infrared images. In this paper we present a computationally simple image fusion technique based on the discrete Haar wavelet transform and apply the technique to combine three images from cameras operating in different wavelength bands. View full abstract»

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  • A high accuracy rate commercial flight coupon recognition system

    Publication Year: 2003 , Page(s): 82 - 86 vol.1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (311 KB) |  | HTML iconHTML  

    In this paper we introduce a practical flight coupon automatic processing system for scanning and recognition. We discuss the coupon classification, character location and binarization. We emphasize a high performance character segmentation and recognition engine, which are proved very effective. The results of experiment and commercial running applying the system are presented. View full abstract»

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  • cdma2000 PCS/cell SiGe HBT load insensitive power amplifiers

    Publication Year: 2005 , Page(s): 601 - 604
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (192 KB) |  | HTML iconHTML  

    A novel power amplifier design technique is proposed that uses load pull measurements in order to optimize linearity and efficiency. Two SiGe HBT MMIC power amplifiers suitable for cell and PCS applications have been realized in a 0.25 μm BiCMOS technology. Thanks to the design technique implemented, cdma2000-1X specifications can be met under output load mismatch up to 4:1 VSWR, thus allowing the removal of the external isolator in the transmitter chain. View full abstract»

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  • Evolved gate arrays for image restoration

    Publication Year: 2004 , Page(s): 1185 - 1192 Vol.1
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (673 KB) |  | HTML iconHTML  

    Evolved gate arrays with a proposed fitness function, are considered for image restoration. In this paper we proposed an on-chip solution for image restoration using an on-chip evolvable hardware method. The corrupted image is considered to be the environment of evolvable hardware structures, which are restoring the original through phenotypic evolution. We compare our solution with some classical techniques for image restoration. View full abstract»

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  • The specialized program for the analysis of parameters of electronic medical measuring complexes

    Publication Year: 2003
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (191 KB)  

    The description of the program intended for the analysis of electric circuits in the field of modelling of biological structures and development of medical devices is given. View full abstract»

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