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Electro/information Technology, 2006 IEEE International Conference on

Date 7-10 May 2006

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Displaying Results 1 - 25 of 125
  • A Fair Capacity Distribution Framework for Wireless Networks with Contention-based Medium Access

    Page(s): 7 - 12
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (8094 KB) |  | HTML iconHTML  

    This paper presents a network-triggered feedback control framework for addressing an inherent hop-unfairness in random access wireless networks, it is experimentally shown that when multiple flows with varying hop-counts compete for wireless bandwidth, the shorter flows can consume an unfair share of the total bandwidth by diverting capacity from longer hop flows. Experimentally we also demonstrate that this effect is not mitigated by the end-to-end feedback mechanism used by rate adaptive transport protocols such as TCP. The goal of this paper is to devise an alternative feedback mechanism that can alleviate this problem of unfair capacity distribution, by introducing a hop-count independent feedback propagation mechanism. This has been accomplished by a network-triggered framework that, unlike TCP, relies on network generated feedbacks for application data rate adaptations. The proposed framework is developed using the ad hoc on-demand distance vector (AODV) routing protocol and is characterized using NS-2 network simulator. Experimental results demonstrate that the proposed mechanism can alleviate the described hop-unfairness problem to a great extent by trading the overall network capacity. Performance of the framework is evaluated for a large number of scenarios and is compared with optimal results, when feasible View full abstract»

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  • An Evaluation for High-Speed Handoffs in 802.11-based Data Networks

    Page(s): 17 - 22
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (7819 KB) |  | HTML iconHTML  

    Handoffs in 802.11-based wireless networks are a critical requirement in today's data networks. The speed at which these handoffs occur is much too slow to enable users to maintain a network session without the loss of connectivity. However, GSM, and other cellular networks, are currently capable of handling handoffs at vehicular rates of travel while still maintaining an existing session. The architectures of both networks are examined and then a limited number of inadequacies of 802.11-based handoffs were examined and contrasted to the performance that currently exists in GSM networks. Spectrum management and a method to integrate these two technologies are not discussed in this paper View full abstract»

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  • Experiment and Analysis on the Comparison of the IEEE 802.11a and 802.11g Wireless Local Area Networks

    Page(s): 13 - 16
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3536 KB) |  | HTML iconHTML  

    An experiment is conducted to compare the performances of path loss and packet loss ratio of the IEEE 802.11a and 802.11g wireless local area networks reflecting the coverage and signal quality. The experiment was performed in typical indoor and outdoor environments by adopting commercial WLAN products. The experimental data show that the IEEE 802.11g WLAN offers a wider coverage and has similar signal qualities in the locations in the proximity while the IEEE 802.11a WLAN demonstrate large variations in the signal qualities. Moreover, the significant impairments of the IEEE 802.11g WLAN are various RF interferences. The IEEE 802.11a WLAN has comparable clear electromagnetic environments View full abstract»

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  • On a Novel Predictive Closed Loop Power Control for DS-CDMA Systems

    Page(s): 27 - 32
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4954 KB) |  | HTML iconHTML  

    In real life the radio signals are subject to Rayleigh fading (fast fading) and interference. Power control is needed to compensate for these effects. This paper proposes a predictive inverse fast power control algorithm (PI-PCA) in DS-CDMA systems. Replacing the conventional power control schemes, this power control scheme controls the mobile's transmitted power based on the prediction of the fading channel attenuation. Furthermore, the performance of our proposed power control scheme is compared with those of the conventional power control schemes. According to the results, we observe that our PI-PCA can maintain the SIR around the target value View full abstract»

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  • Using the Global Positioning System (GPS) to add Intelligence to Wireless Handover in WLAN

    Page(s): 23 - 26
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4418 KB) |  | HTML iconHTML  

    The progress of communication has led us to a point whereby it is desirable for the advanced wireless technology such as laptops and cellular phones to have seamless roaming when communicating or holding a session with another communication entity. It is therefore important that the underlying mechanisms and methods of packet delivery and handoff latency to a mobile communicating node be made robust with little disruption to real time communicating processes. The research proposed in this paper considers mobile IPv6 (MIPv6) improvement opportunities over an IEEE 802.11g using the Global Positioning System (GPS) technology View full abstract»

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  • Developing Active Sensor Networks with Micro Mobile Robots

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (7336 KB) |  | HTML iconHTML  

    In this paper a new sensor network architecture called active sensor network (ASN) is developed. By integrating multiple small, sensor network-friendly mobile robots into a traditional sensor network, a closed-loop, dynamic, adaptive sensor network is formed. Such sensor networks have the following merits: adaptivity, self healing, responsiveness and longer lifetime. This paper focuses on the distributed sensor node localization and service set partition among multiple micro mobile robots. For node localization, a potential-based robot area partition algorithm and a distributed localization algorithm are developed. For service set partition, a load-balanced partitioning algorithm is developed. Simulation results verify the proposed algorithms View full abstract»

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  • Distributed Modeling of the Solution Selection and Its Cooperative Agents

    Page(s): 49 - 54
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6890 KB) |  | HTML iconHTML  

    Many international enterprises, organizations and governments often have to select a solution for a complicated issue. For this, the key agents (leaders) dispatch the tasks to many agents, call for lots of meetings and try to reach a conclusion. The process will last out among groups of agents, in many different locations, and have many different phases; it is always an intermittent, distributed and interlaced procedure. We develop a distributed modeling methodology-DMSS (distributed modeling of the solution selection) and its' supporting system on network, which is to build static and dynamic models of the objects and the processes with the selecting procedure. It will give the agents a "thinking-grid" among a mass of goals, agents, solutions and conditions. The modeling process is traced and conducted by cooperative software-agents View full abstract»

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  • Frequency Analysis of Time-Varying Systems

    Page(s): 33 - 36
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3160 KB) |  | HTML iconHTML  

    A method of frequency analysis is presented that can be used to determine the response of time-varying systems. The method is based on Laplace transformation of functions. As a result, the homogenous solution of ordinary linear differential equations with variable coefficients is obtained. The method is used for frequency analysis and design of variable networks. The extension to nonlinear systems is possible View full abstract»

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  • A Decision-Aided Carrier Recovery Method with the New Low Complexity MMSE Algorithm

    Page(s): 37 - 42
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5768 KB) |  | HTML iconHTML  

    A new adaptive carrier synchronization applying the extended Kalman filtering algorithm is proposed. The state model in the new algorithm uses only phase rather than both phase and frequency in the conventional method. The frequency is used as an input term to the state equation and estimated by a phase error detector. A reduced observation model is also considered to reduce complexity by only calculating scalar instead of matrix in the Kalman recursions. The simulations show that the one-state Kalman algorithm has better performance and lower complexity than the two-state Kalman algorithm. The proposed algorithm is applied to the cable modem downstream system to demonstrate its effectiveness View full abstract»

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  • Source Separation in the Time-Frequency Domain by Maximizing an Information-Theoretic Criterion

    Page(s): 43 - 48
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5670 KB) |  | HTML iconHTML  

    Blind source separation aims at recovering the original source signals given only observations of their mixtures. Some common approaches to the source separation problem include second or higher order statistics based methods, and independent component analysis. Most of these methods are developed in the time domain, and thus, inherently assume the stationarity of the underlying signals. Since most real life signals of interest are non-stationary, there have been efforts to perform source separation in the time-frequency domain. In this paper, we propose a new approach for source separation on the time-frequency plane using an information-theoretic cost function. Jensen-Renyi divergence, as adapted to time-frequency distributions, is introduced as an effective cost function to extract sources that are disjoint on the time-frequency plane. The sources are extracted through a series of Givens rotations and the optimal rotation angle is found using the steepest descent algorithm. The performance of the proposed method is illustrated and quantified through examples View full abstract»

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  • A Direct Path Interference Cancellation Approach to Passive Radar Based on FM Radio transmitter

    Page(s): 55 - 59
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4195 KB) |  | HTML iconHTML  

    Target detection by non-cooperative illuminator is a research hotspot in electronic warfare field, with four countering' potential advantages. One of the major problems in bistatic radars with continuous waves is the direct path interference (DPI). The conventional solution to this problem is to use an adaptive antenna by steering null towards the interference. Unfortunately the null depth obtained by this technology is not enough for surveillance radar. First of all DPI based on FM broadcast transmitter in passive radar is analyzed in this paper. Secondly, a DPI cancellation approach based on adaptive fractional delay estimation (AFDE) is in detail introduced how to deal with this problem. Finally, a passive radar experimental system based on FM broadcast transmitter is discussed. Simulation results by applying real collected data show the provided method is effective View full abstract»

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  • Evaluation of Angular Spectrum Approach for Simulations of Spherically Focused Ultrasound Phased Arrays

    Page(s): 66 - 71
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5922 KB) |  | HTML iconHTML  

    Modeling the pressure fields of large ultrasound phased arrays using conventional methods is extremely time-consuming because of the huge number of computational points and transducer elements. The angular spectrum approach (ASA) can simulate the fields accurately with great reduction of computational time. The errors involved with ASA are mostly due to the lack of spectral sampling and this can be compensated by restricting the angular frequency components adaptively with respect to the propagation distance. The performance of the ASA is evaluated by modeling the pressure field generated by a spherical phased array with on-axial, off-axial focus and multiple-foci patterns. With moderate sampling and medium size of source planes, the ASA produces accurate results throughout the three dimensional (3D) computational volume and reduces the simulation time significantly View full abstract»

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  • Applications of Fuzzy and Neuro-Fuzzy in Biomedical Health Sciences

    Page(s): 60 - 65
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (7055 KB) |  | HTML iconHTML  

    Fuzzy and neuro fuzzy logic concepts have been used for variety of applications, where machine intelligence can be used for the system. The fuzzy logic concept has been used for a number of biomedical applications also. We have used fuzzy and neuro fuzzy approach for tackling surgery procedures of a patient suffering from stress urinary incontinence (SUI). We have further extended the application of fuzzy and neuro fuzzy logic for predicting the approximate recovery time of a patient under physical therapy suffering from stroke, paraplegia, quadriplegia etc. Here, we have outlined methods for above mentioned biomedical applications based on a knowledge base created from the patients of different age groups. We have shown our simulation results with input data and possible outcomes with the fuzzy and neuro fuzzy system View full abstract»

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  • A Technique to Reduce Information Loss in PPG Pulse Waveform Refining Processing

    Page(s): 72 - 75
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4159 KB) |  | HTML iconHTML  

    In order to conduct advanced signal processing techniques so as to extract reliable clinical information contained in photoplethsmographic (PPG) signal, PPG pulse waveform refining processing over a relatively wide range of the heart rate change is involved. The key point during this refining stage is to reduce the information loss caused by the waveform distortion so that the signal energy can be accumulated as coherently as possible. In this respect, however, the conventional time-scale-normalization technique will meet serious difficulty. To overcome this difficulty, a PPG pulse waveform refining processing technique, named truncation/extrapolation technique, is proposed in this paper. The rationale of the proposed technique is to preserve the shape pattern of the most significant parts of the pulse waveform at the expanse of the distortion of the insignificant part. Analysis and comparison between two techniques verify the effectiveness of the proposed method View full abstract»

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  • A comparison of pressure calculation methods that subtract near field singularities from analytical expressions developed for triangular apertures

    Page(s): 76 - 80
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5259 KB) |  | HTML iconHTML  

    Previous simulation studies have shown that the fast nearfield method (FNM) is faster and more accurate than the impulse response and rectangular radiator methods for nearfield pressure calculations. The FNM achieves this advantage by subtracting a singularity from a one-dimensional integral expression, which improves the numerical convergence relative to these other techniques. A related approach subtracts a singularity from the two-dimensional (2D) Rayleigh integral, thereby separating the Rayleigh integral into two parts. In this approach, one integral is evaluated analytically and the remaining terms are evaluated numerically. Numerical calculations are performed with a seven point Gauss quadrature rule. This approach is evaluated for a triangular source and compared to results obtained from FNM calculations. For larger triangular sources, the 2D Rayleigh integral is subdivided into smaller triangular patches, and then the results are superposed. Results show that for an equilateral triangle with sides equal to one wavelength, this approach achieves a 10% peak error without subdividing the source, and a 1% peak error is obtained when the source is subdivided into four smaller triangles. Computation times with this approach are 0.140s and 0.2190s for 10% and 1% peak errors, respectively, whereas the FNM results for the same peak errors are 0.031s and 0.047s for a reduction in the computation time by a factor of 4.52 and 4.66, respectively. This shows that FNM calculations converge more rapidly than the method that subtracts the singularity from the 2D Rayleigh integral. Future efforts will replace this 2D Rayleigh integral calculation with the FNM in large-scale simulations of ultrasound devices designed for thermal therapy applications View full abstract»

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  • Fuzzy Logic for Harmonic Distortion Diagnosis in Power Systems

    Page(s): 87 - 92
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6221 KB) |  | HTML iconHTML  

    Harmonic distortion in power systems is an old problem which continues to grow in importance due to the proliferation of non-linear loads and of sensitive electronic devices. Thus, the need of standards to limit such distortion is required. Due to the time-varying nature of the distortion more advanced techniques are required to properly quantify their impact. This paper proposes the utilization of fuzzy logic to analyze, compare, and diagnose harmonic distortion indices in a power system View full abstract»

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  • On-Chip Compensated Error Amplifier for Fast Transient DC-DC Converters

    Page(s): 103 - 108
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6593 KB) |  | HTML iconHTML  

    A novel on-chip compensated error amplifier for fast transient response of DC-DC converters is presented in this paper. The error amplifier uses on-chip current-mode Miller capacitor to replace a large off-chip capacitor. We only use three transistors and one voltage follower to implement this novel on-chip compensated error amplifier for fast transient DC-DC converters. Owing to the current-mode implementation, we can redirect the equivalent current to charge or discharge the output capacitor of the error amplifier to improve the transient response time. Not only on-chip compensated error amplifier is implemented without off-chip components and I/O pins, but also it can have fast transient response. The analytic equations guarantee the compensated correctness of the proposed circuit. With the proposed error amplifier, the transient response of DC-DC converters is improved significantly. Simulation results demonstrate the stability and the fast transient response of the DC-DC converters View full abstract»

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  • Fault Types and Mitigation Techniques of PMAC Machines

    Page(s): 97 - 102
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5849 KB) |  | HTML iconHTML  

    The ability to detect and mitigate a fault is critical for electrical drives and machines in applications that require high reliability. In this work, a permanent magnet AC drive and machine is examined and the most critical areas susceptible to faults are analyzed. Remedial designs are considered for mitigating a fault View full abstract»

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  • A Step Voltage Response Method for Identification of Induction Motor Parameters at Stand Still

    Page(s): 109 - 112
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3544 KB) |  | HTML iconHTML  

    For the correct operation of a field oriented control drive, parameters of the induction motor should be fully defined. To obtain the parameters a dc step voltage response method is used. A dc voltage step is applied to the stator winding and the stator current is recorded. Four samples of the latter are needed to calculate the stator resistance, the stator self-inductance, the rotor time constant, and the linkage constant. The high accuracy of these parameters is achieved by using an iteration algorithm. The small number of iterations (5-10) gives accuracy to a fraction of a percent View full abstract»

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  • Measuring the Capacitance of Electrical Wiring and Humans for Proximity Sensing with Existing Electrical Infrastructure

    Page(s): 93 - 96
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3748 KB) |  | HTML iconHTML  

    In a recent series of electric field sensing experiments, a Theremin was used to measure the mutual capacitance between a human being and a length of electrical wiring. The instrument, based on the LM555 circuit, measures the deflections in capacitance due to the proximity of a human. The measurements are repeatable, and the difference in capacitance for a person at one-half meter with a person at one meter is consistent with the difference computed assuming the human acts as a ground plane for the wiring. Much of the current literature in electric field sensing focuses on measures and models of mutual capacitance for humans interacting with plate conductors, especially fingers near touch screens. Our investigation considers conducting wires to allow development of portable, rapidly deployable human proximity sensing systems that exploit existing electrical infrastructure in buildings. The experiment described here demonstrates that sensing with wires is possible at ranges on the order of a meter and provides evidence that modeling the person as a ground plane of finite extent provides a rough estimate of the change in mutual capacitance View full abstract»

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  • 3 - DOF Planar Induction Motor

    Page(s): 81 - 86
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4503 KB) |  | HTML iconHTML  

    The paper discusses characteristics and experimental results of a multi-axes direct drive system. The investigated planar motor works with individually controlled single-sided linear induction motors in a common mover. It can move in three degrees of freedom (3-DOF), i.e. in the translation coordinates x and y and in the rotation coordinate phizb. The construction is explained and the functionality is proven by a tracking curve. Advantages of planar motors to other drive solutions are discussed View full abstract»

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  • A New Technique to Exploit Instruction-Level Parallelism for Reducing Microprocessor Power Consumption

    Page(s): 119 - 124
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6368 KB) |  | HTML iconHTML  

    A large portion of the power consumed by a high-performance out-of order microprocessor is attributed to units within the instruction window pipeline stages, from dispatch to commit. Power consumed within the window, and by the overall processor, is reduced by dynamic size adjustment of those units based on program needs. In this article, we introduce a new metric for estimating the instruction level parallelism (ILP) for a group of instructions using a simple ratio of the longest data dependence path's length to the total number of instructions in the group, hence referred to as the longest dependence path ratio (LDPR). We couple this concept with a design where units in the instruction window are divided into segments that are dynamically disabled for power savings when they are unused. The maximum number of enabled segments that a program can utilize is limited based on the amount of ILP estimated using the LDPR. We also show how measuring the LDPR is implemented by a simple extension to the dependence-check-logic at dispatch stage. Results using the LDPR show that power is saved with a minimal impact on performance, by reducing the number of available segments, not only in low ILP periods, but also over those having very high ILP. Using the Wattch power models and the MinneSPEC benchmarks, the LDPR implementation achieves an average of 36.5% of window power savings and 11% overall processor power savings, and with an average performance loss of a very modest 1.9% View full abstract»

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  • Importance of Architecture Knowledge and Algorithm Redesign for Efficient DSP Programming

    Page(s): 131 - 136
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6962 KB) |  | HTML iconHTML  

    In the recent past, there has been an increase in the demand for vision-based embedded systems. These applications have high computational requirements and therefore severely strain the limited resources available in most embedded systems. With today's high-performance digital signal processors (DSPs) offering additional features to address multi-media needs, it is necessary to understand and exploit these features to realize a real-time vision-based application. Algorithm level optimizations also contribute to reduction in processing power and memory requirements. Hence, software redesign is an important process for optimizing the software. In this paper, we emphasize the need for an in-depth knowledge of the architecture for optimal, cost-effective real-time performance. We also explain the impact of various optimization techniques on the execution time and memory consumption of a simple block-based algorithm and a complex real-world stationary vehicle detection algorithm View full abstract»

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  • Reconfigurable Factory-wide Resource-based System Integration for Control

    Page(s): 125 - 130
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (8110 KB) |  | HTML iconHTML  

    Next generation of manufacturing systems will need to be reconfigurable-capable of producing exactly the volume and type of products desired, exactly when demanded by the market- in order to accommodate the rapid changes in product design necessitated by ever-changing customer demands. The corresponding factory control systems will consist of a conglomeration of hardware and software resources that must work together to achieve factory-wide targets of throughput and quality. This paper addresses the requirement of consolidation of software and hardware control with the design of a factory-wide resource-based reconfigurable control system. This system extends reconfigurable software event-based control by considering a manufacturing system as a set of decentralized resources of both hardware and software instead of a set of dissimilar components. Central to the solution is a mechanism for embedding control rules in a database to determine appropriate actions corresponding to events View full abstract»

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  • Hardware-Software Co-design of a Fingerprint Matcher on Card

    Page(s): 113 - 118
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (7175 KB) |  | HTML iconHTML  

    Nowadays, security is becoming a real need for society and a real challenge for those everyday activities such as access control, cash terminals, public transport, Internet... where user authentication is required prior to giving access to confidential information, relevant places or restricted resources. The implementation of a reliable personal recognition system not based on vulnerable topics such as physical keys or passwords is required. Biometrics-based authentication techniques (e.g. face, iris, fingerprint recognition...) in conjunction with smart cards technologies bring a challenging solution to this need. This paper describes the hardware-software co-design of a fingerprint match on card system responsible for matching two fingerprint minutiae sets in a reliable and secure way. The proposed system architecture is composed by a general-purpose 8-bit microcontroller and a 40-kgates FPGA, all embedded in a system on chip device. A good solution is detailed from a performance versus cost point-of-view View full abstract»

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