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Informacje o czasopiśmie
Format
Czasopismo
eISSN
1178-5608
Pierwsze wydanie
01 Jan 2008
Częstotliwość wydawania
1 raz w roku
Języki
Angielski

Wyszukiwanie

Tom 3 (2010): Zeszyt 4 (January 2010)

Informacje o czasopiśmie
Format
Czasopismo
eISSN
1178-5608
Pierwsze wydanie
01 Jan 2008
Częstotliwość wydawania
1 raz w roku
Języki
Angielski

Wyszukiwanie

14 Artykułów
access type Otwarty dostęp

A Wavelet-Based Bridge Weigh-In-Motion System

Data publikacji: 13 Dec 2017
Zakres stron: 573 - 591

Abstrakt

Abstract

Bridge Weigh-in-Motion systems can be used to estimate vehicle parameters such as velocity, axle loads, or the distance between axles without affecting the traffic. These parameters and the classification of vehicles are necessary to determine vehicle overload and hence may help to reduce risks for road users and road infrastructure and allow optimized planning of maintenance work.

The Bridge Weigh-in-Motion system developed is based on a crack displacement sensor with intelligent data processing algorithms: In a first step, the number of axles, the distance between axles, and the velocity of the vehicle is obtained from the crack displacement signal by means of wavelet decomposition. In a subsequent step, the axle loads are found by means of optimizing the weights for axle loads that the measured crack displacement signal can be approximated by a superposition of (shifted and extended/compressed) ‘Lines of Influence’. Intensive test runs have been performed to verify results of the Bridge Weigh-in-Motion system.

Słowa kluczowe

  • Bridge Weigh-in-Motion System
  • Wavelet Decomposition
  • Axle Load
  • Distance between Axles
  • Velocity Determination
access type Otwarty dostęp

Study Of Thermal-Magnetic Driving For Next-Generation Inkjet

Data publikacji: 13 Dec 2017
Zakres stron: 592 - 604

Abstrakt

Abstract

In this paper, the authors proposed a novel type of inkjet where the ink is driving by maxwell stress employing the characteristic of thermalmagnetic. Different with the traditional inkjet technology like the piezo-vibration driving type or bubble driving type, in the proposed approach the moving elements or high temperature is absolutely unnecessary and having simple structure, so that high durability and reliability is promising with small size and strong pumping force. The working mechanism of the proposed method was explained and demonstrated by analysis and experiment.

Słowa kluczowe

  • inkjet
  • thermalmagnetic
  • magnetic fluid
  • functional ink
  • direct drawing
  • wiring
  • micro pattern
  • coating film
  • environment
  • energy saving
access type Otwarty dostęp

High Sensitivity Methane Sensor By Chemically Deposited Nanocrystalline Zno Thin Film

Data publikacji: 13 Dec 2017
Zakres stron: 605 - 620

Abstrakt

Abstract

-Nanocrystalline n-ZnO thin films were deposited on SiO2-coated (0.45 μm) p type Si substrates (10-20Ω-cm) by a low cost chemical deposition technique to fabricate ZnO-based resistive sensors for methane detection. The nanocrystalline ZnO needle like structures were grown on RCA cleaned p-Si<100> substrates by successive immersion (100-200 times) into a Sodium Zincate bath (0.125M) kept at room temperature and DI water maintained at 90 °C . The Sodium Zincate was prepared by reacting Zinc Sulphate and excess Sodium Hydroxide in aqueous solution. The film thickness of 1.5 μm (approx.) for 75 dippings was obtained. The dipping time is 1 second. The annealing was done at a lower temperature (150 °C) for 30 minutes in air. Structural characteristics were studied by FESEM and EDAX to indicate the formation of ZnO with vertical orientation. The hexagonal needle like structures of 0.3-0.5μm diameter and 1-1.5μm length were formed. The resistance of the ZnO films in ambient air (zero level for gas sensing) was found to be stable and reproducible after several thermal cyclings. Surface modification with palladium (0.01% PdCl2 for 5 seconds) was done to enhance sensitivity; so that the ZnO thin films can give significant response to target gases at the operating temperature of as low as 130°C, compared to the normal operating temperature range of 200–400°C for zinc oxide resistive gas sensors. The planar gold contacts were deposited by vacuum evaporation technique. The device was then tested for its methane sensing property at different operating temperatures (150,175,200,250,300,350°C) and at 5 different methane concentrations (0.01,0.05,0.1,0.5,1%) taking N2 as a carrier gas. The response magnitude, response time and recovery time were studied in detail for both Pd modified and unmodified ZnO film. The maximum response of 99.76% and the lowest response time of 39 seconds were obtained at 200°C for Pd modified sensor. A high sensitivity to methane even at low temperature (130°C) was observed comparable to those obtained by more sophisticated and expensive deposition process e.g. MOCVD.

Indexterms

  • Nanocrystalline zinc oxide
  • Methane sensor
  • Pd modified
  • Fast response
access type Otwarty dostęp

An Approach Towards Development Of Pmv Based Thermal Comfort Smart Sensor

Data publikacji: 13 Dec 2017
Zakres stron: 621 - 642

Abstrakt

Abstract

ASHRAE 55-2004 and ISO 7730 standards failed to predict actual comfort level and lead to oversize design of HVAC system. So proper thermal environment monitoring is an important subject to have right size of HVAC systems. A prototype thermal EM system has been developed. Thermal environment parameters such as: temperature, relative humidity, CO and CO2 are measured by using the developed system. These data are used to calculate the thermal comfort index. The subjective judgments and the calculated PMV are compared with the results. The results showed the possibility of using PMV based thermal comfort smart sensor.

Słowa kluczowe

  • Predicted mean vote (PMV)
  • Environment monitoring system (EMS)
  • Indoor environment quality
  • Thermal comfort index
access type Otwarty dostęp

Nanosensors Engineering: I. Structurally Modulated Sno2 Nanowires

Data publikacji: 13 Dec 2017
Zakres stron: 643 - 654

Abstrakt

Abstract

– The results of research aimed at the gas sensing nanowires (NWs) engineering are presented. Structurally modulated SnO2 NWs were obtained at 900°C in the modified vapor-solid process, allowing that NW morphology could be encoded in a programmable way along its length. PVD technique was used for Ti/Au electrical contacts deposition and gas sensitive nanoscale chemiresistors formation.

Created nanostructures were characterized for their gas sensing performance. It was established that structurally-modulated NWs possess better gas sensitive characteristics in comparison with the straight ones. Obtained results are discussed from the positions of single-crystal “necks” formation in NWs.

Słowa kluczowe

  • Nanostructure
  • Tin dioxide
  • Nanowire
  • Chemoresistor
  • Structural modulation
  • Morphology
access type Otwarty dostęp

Model identification and Smart structural vibration Control using H controller

Data publikacji: 13 Dec 2017
Zakres stron: 655 - 671

Abstrakt

Abstract

A smart structure plays a vital role in aerospace applications and robotics and other applications. It presents many challenging control problems due to their non-linear dynamic behavior. The Objective of this work is to design a controller that minimizes the structural vibration using H∞ controller. Vibration as a measured parameter has been used to evaluate model of a nonlinear process (piezoelectric actuator and sensor) at different modes .The model was generated using an ARMAX technique. By selecting appropriate weighting functions H controller were designed based on mixed sensitivity approach using singular loop shaping method. The performance of H controller was compared with LQG controller based on vibration reduction. From the results it is observed that the H∞ controller is the best suited for smart structural process.

Słowa kluczowe

  • controller
  • ARMAX
  • smart structure
  • LQG
  • weighting function
  • loop shaping
  • weighting function
access type Otwarty dostęp

Review Of Wet Gas Flow Measurement Using Venturi Tubes And Radio Active Materials

Data publikacji: 13 Dec 2017
Zakres stron: 672 - 689

Abstrakt

Abstract

This paper introduces the application of Venturi flow meter for wet gas flow measurement. Wet gas which is a gas containing small amount of liquid is mostly encountered in gas wells where the extracted gas has water and condensate inside. Venturi flow meters which originally were introduced for single phase flow measurement are adapted for wet gas measurement. In this paper, we elaborate using of Venturi meter as a device for measuring wet gas flow and explain versatile methods for correcting the reading of Venturi tube for wet gas application. Tracer injection method is introduced as a manual tool for measuring water and condensate flow rate in wet gas fluid. Also radioactive measuring method has been introduced as an automatic method for measuring the ratio between gas, water and condensate in wet gas fluid. Finally different aspects of using radioactive sources are elaborated.

Słowa kluczowe

  • Wet gas
  • Flow measurement
  • Venturi
  • Radio-active densitometer
  • Multi phase flow measurement
access type Otwarty dostęp

A Coarse-to-Fine Approach for Remote-Sensing Image Registration Based on a Local Method

Data publikacji: 13 Dec 2017
Zakres stron: 690 - 702

Abstrakt

Abstract

Multispectral satellite imagery registration is a fundamental step for remote sensing applications such as global change detection, feature classification, and image fusion. Since image registration via the manual selection of control points is a repetitive and time-intensive task, a more efficient automatic coarse-to-fine algorithm for multispectral remote sensing image registration is proposed in this paper. First, for the coarse registration, the Haar Wavelet Transform (HWT) is adopted to produce lower-resolution levels of reference and input images; then, the Speeded Up Robust Features (SURF) algorithm is utilized for quickly searching for matching points. After the coarse registration is completed, the Harris operator is used to extract feature points, and initial correspondences are established using the normalized cross-correlation to achieve the fine registration. Second, in order to remove mismatched points, the RANdom SAmple Consensus (RANSAC) algorithm is applied to putative correspondences. Due to large amount of satellite image data available, we used block processing in the refined registration to increase the efficiency in memory use. Finally, the final transformation function is obtained via the local weighted mean method in order to deal with local geometric differences between the reference and input images. Compared to global registration by manually selecting the control points, the proposed method is fully automatic and computationally efficient. Experimental results with well-known data sets (Worldview-1,2 and Quickbird remote-sensing images) again demonstrate the accuracy and effectiveness of the proposed algorithm for multispectral remote-sensing image registration.

Słowa kluczowe

  • Multispectral satellite image
  • Image registration
  • SURF
  • RANSAC
access type Otwarty dostęp

Characterization Of Cracks And Delaminations Using Pwas Ad Lamb Wave Based Time-Frequency Methods

Data publikacji: 13 Dec 2017
Zakres stron: 703 - 735

Abstrakt

Abstract

Use of smart sensor technology along with intelligent signal processing plays a crucial role in the implementation and working of ultrasonic wave based damage detection system. In this work, the interaction of A0 Lamb mode with damages like crack and delamination are studied. Piezoelectric Wafer Active Sensors (PWAS) are used for generation of Lamb waves to detect damages in metal and composite structures. Experiments were conducted on aluminum plates to study the interaction of Lamb wave with crack oriented at different angles and on a titanium turbine blade of complex geometry with a fine surface crack. A geodesic based Lamb wave approach was employed to locate a crack in an aluminum plate. The existing geodesic algorithm is improved by replacing the Dijkstra’s algorithm with the accurate fast marching method. Further, the interactions of A0 mode with multiple layer delaminations in glass fiber epoxy composite laminates were studied. Spectral Finite Element Method (SFEM) is used for numerical simulation to validate the experimental results. Time-frequency analysis techniques, namely Wavelet Transform (WT) and Hilbert Huang transform (HHT) are used to study the experimental signals and their performances were compared. This study provides significant insight into the problem of identifying localized damages in the structure using integrated PWAS and dispersion of multi-frequency signal after they interact with different types of damage.

Słowa kluczowe

  • Lamb waves
  • PWAS
  • Time-frequency analysis
  • Composites
  • Geodesics
  • Spectral Finite element method
  • Wavelet transform
  • Hilbert-Huang transform
  • Delamination
access type Otwarty dostęp

Application Of Draw Wire Sensor In Position Tracking Of Electro Hydraulic Actuator System

Data publikacji: 13 Dec 2017
Zakres stron: 736 - 755

Abstrakt

Abstract

Draw-wire sensor is classified as a contact measurement method. This sensor is ideal for applications with large measuring ranges, small sensor dimensions and when a low cost solution is required. The objective of this research is to explain the application of a draw-wire sensor in position tracking of electro-hydraulic actuator system. The work started with the modeling of the electro hydraulic actuator system. Draw wire sensor is attached to the load of electro hydraulic system to measure its motion when an input signal is injected to the system. The sensor output is the displacement in millimeter and converted to the voltage based on the input signal given. These input and output readings are collected and applied to a system identification procedure in order to obtain the best mathematical model of the system. The modeling process is followed by designed a proportional integral and derivative controller (PID) for the system to assure the output is tracking the input given. The designed controller is applied to the system in both simulation and real time mode. The output performance of the system for these two modes is compared and it can be seen that the simulation and real-time output are almost similar. The overall process of this work shows the important role of draw wire sensor in capturing the output data of the electro hydraulic actuator system precisely either with or without controller. Other displacement transducer might be used in future work of position tracking of electro-hydraulic actuator system.

Słowa kluczowe

  • Electro-hydraulic actuator
  • draw wire sensor
  • system identification
  • ARX model
  • PID controller
access type Otwarty dostęp

Long-Reach Flying Functional Inkjet System By Employing Electrostatic Acceleration

Data publikacji: 13 Dec 2017
Zakres stron: 756 - 770

Abstrakt

Abstract

In this paper, the authors proposed a novel idea of a long-reach flying inkjet system employing electrostatically-accelerated ink drop for the purpose of functional ink micro pattern plotting by contact-free and environment friendly. Proposed working principle was demonstrated through experiment and analysis. At the 5-mm of electrode gap and φ 120 μm of nozzle, the applicable maximum voltage was 3.5kV realizing 67% up (1.67 times) of droplet flying velocity by one-step of accelerating. By φ 10 μm of droplet, over 35m/s of flying velocity was promising and by 2~3 steps of acceleratingfurther of speed increment could be expected.

Słowa kluczowe

  • long-reach
  • contact free
  • functional ink
  • direct wiring
  • micro pattern
  • coating film
access type Otwarty dostęp

Microcontroller based Power Efficient Signal Conditioning Unit for Detection of a Single Gas using MEMS based Sensor

Data publikacji: 13 Dec 2017
Zakres stron: 771 - 782

Abstrakt

Abstract

-A low power MEMS based sensor along with the embedded power efficient signal conditioning unit (Microcontroller based), which can be used with any suitable sensor-network to detect and quantify variations in a particular gas concentration, has been reported in this paper. The power consumption of the MEMS gas sensor is ~ 70mW to 100mW depending upon its operating temperature (150-250°C) and that of entire signal conditioning unit (consisting of low noise amplifier, switch, microcontroller and power management chip) is ~ 36mW in the ON state and only ~7.2μW in OFF state (sleep mode). The test gas in this particular case was methane for which sensor resistance varied from 100KΩ to 10KΩ. This hybrid sensor system is very much suitable for detecting a single gas with display of corresponding gas concentrations and subsequent alarming if the threshold limit is crossed.

Słowa kluczowe

  • MEMS
  • Gas sensor
  • Low power
  • Microcontroller
  • Signal Conditioning
access type Otwarty dostęp

System Identification Of Nonlinear Autoregressive Models In Monitoring Dengue Infection

Data publikacji: 13 Dec 2017
Zakres stron: 783 - 806

Abstrakt

Abstract

This paper proposes system identification on application of nonlinear AR (NAR) based on Artificial Neural Network (ANN) for monitor of dengue infections. In building the model, three selection criteria, i.e. the final prediction error (FPE), Akaike’s Information Criteria (AIC), and Lipschitz number were used. Each of the models is divided into two approaches, which are unregularized approach and regularized approach. The findings indicate that NARMAX model with regularized approach yields better accuracy by 80.60%. The best parameters’ settings for this thesis can be found using the Lipschitz number criterion for the model order selection with artificial neural network structure of 4 trained using the Levenberg Marquardt algorithm.

Słowa kluczowe

  • dengue fever
  • NAR model
  • AIC
  • Lipschitz
  • FPE
  • ROC and AUC
access type Otwarty dostęp

Nanosensors Engineering: Ii. Superficial Functionalization Of Sno2 Nanowire For Sensing Performance Improvement

Data publikacji: 13 Dec 2017
Zakres stron: 807 - 819

Abstrakt

Abstract

Paper presents results of study aimed the tin dioxide nanowire gas sensing performance improvement via in situ functionalization with NiO. Developed nanostructures have demonstrated improved by order gas sensitivity toward H2 and CO and drastic increase of selectivity to H2 against CO. Obtained results are discussed from the point of view of NiO/Sno2 heterojunction formation and its influence on electrical transport through nanowire and nanowire interaction with target gases.

Słowa kluczowe

  • Nanowire
  • tin dioxide
  • nickel oxide
  • chemoresistor
  • functionalization
  • heterojunction
14 Artykułów
access type Otwarty dostęp

A Wavelet-Based Bridge Weigh-In-Motion System

Data publikacji: 13 Dec 2017
Zakres stron: 573 - 591

Abstrakt

Abstract

Bridge Weigh-in-Motion systems can be used to estimate vehicle parameters such as velocity, axle loads, or the distance between axles without affecting the traffic. These parameters and the classification of vehicles are necessary to determine vehicle overload and hence may help to reduce risks for road users and road infrastructure and allow optimized planning of maintenance work.

The Bridge Weigh-in-Motion system developed is based on a crack displacement sensor with intelligent data processing algorithms: In a first step, the number of axles, the distance between axles, and the velocity of the vehicle is obtained from the crack displacement signal by means of wavelet decomposition. In a subsequent step, the axle loads are found by means of optimizing the weights for axle loads that the measured crack displacement signal can be approximated by a superposition of (shifted and extended/compressed) ‘Lines of Influence’. Intensive test runs have been performed to verify results of the Bridge Weigh-in-Motion system.

Słowa kluczowe

  • Bridge Weigh-in-Motion System
  • Wavelet Decomposition
  • Axle Load
  • Distance between Axles
  • Velocity Determination
access type Otwarty dostęp

Study Of Thermal-Magnetic Driving For Next-Generation Inkjet

Data publikacji: 13 Dec 2017
Zakres stron: 592 - 604

Abstrakt

Abstract

In this paper, the authors proposed a novel type of inkjet where the ink is driving by maxwell stress employing the characteristic of thermalmagnetic. Different with the traditional inkjet technology like the piezo-vibration driving type or bubble driving type, in the proposed approach the moving elements or high temperature is absolutely unnecessary and having simple structure, so that high durability and reliability is promising with small size and strong pumping force. The working mechanism of the proposed method was explained and demonstrated by analysis and experiment.

Słowa kluczowe

  • inkjet
  • thermalmagnetic
  • magnetic fluid
  • functional ink
  • direct drawing
  • wiring
  • micro pattern
  • coating film
  • environment
  • energy saving
access type Otwarty dostęp

High Sensitivity Methane Sensor By Chemically Deposited Nanocrystalline Zno Thin Film

Data publikacji: 13 Dec 2017
Zakres stron: 605 - 620

Abstrakt

Abstract

-Nanocrystalline n-ZnO thin films were deposited on SiO2-coated (0.45 μm) p type Si substrates (10-20Ω-cm) by a low cost chemical deposition technique to fabricate ZnO-based resistive sensors for methane detection. The nanocrystalline ZnO needle like structures were grown on RCA cleaned p-Si<100> substrates by successive immersion (100-200 times) into a Sodium Zincate bath (0.125M) kept at room temperature and DI water maintained at 90 °C . The Sodium Zincate was prepared by reacting Zinc Sulphate and excess Sodium Hydroxide in aqueous solution. The film thickness of 1.5 μm (approx.) for 75 dippings was obtained. The dipping time is 1 second. The annealing was done at a lower temperature (150 °C) for 30 minutes in air. Structural characteristics were studied by FESEM and EDAX to indicate the formation of ZnO with vertical orientation. The hexagonal needle like structures of 0.3-0.5μm diameter and 1-1.5μm length were formed. The resistance of the ZnO films in ambient air (zero level for gas sensing) was found to be stable and reproducible after several thermal cyclings. Surface modification with palladium (0.01% PdCl2 for 5 seconds) was done to enhance sensitivity; so that the ZnO thin films can give significant response to target gases at the operating temperature of as low as 130°C, compared to the normal operating temperature range of 200–400°C for zinc oxide resistive gas sensors. The planar gold contacts were deposited by vacuum evaporation technique. The device was then tested for its methane sensing property at different operating temperatures (150,175,200,250,300,350°C) and at 5 different methane concentrations (0.01,0.05,0.1,0.5,1%) taking N2 as a carrier gas. The response magnitude, response time and recovery time were studied in detail for both Pd modified and unmodified ZnO film. The maximum response of 99.76% and the lowest response time of 39 seconds were obtained at 200°C for Pd modified sensor. A high sensitivity to methane even at low temperature (130°C) was observed comparable to those obtained by more sophisticated and expensive deposition process e.g. MOCVD.

Indexterms

  • Nanocrystalline zinc oxide
  • Methane sensor
  • Pd modified
  • Fast response
access type Otwarty dostęp

An Approach Towards Development Of Pmv Based Thermal Comfort Smart Sensor

Data publikacji: 13 Dec 2017
Zakres stron: 621 - 642

Abstrakt

Abstract

ASHRAE 55-2004 and ISO 7730 standards failed to predict actual comfort level and lead to oversize design of HVAC system. So proper thermal environment monitoring is an important subject to have right size of HVAC systems. A prototype thermal EM system has been developed. Thermal environment parameters such as: temperature, relative humidity, CO and CO2 are measured by using the developed system. These data are used to calculate the thermal comfort index. The subjective judgments and the calculated PMV are compared with the results. The results showed the possibility of using PMV based thermal comfort smart sensor.

Słowa kluczowe

  • Predicted mean vote (PMV)
  • Environment monitoring system (EMS)
  • Indoor environment quality
  • Thermal comfort index
access type Otwarty dostęp

Nanosensors Engineering: I. Structurally Modulated Sno2 Nanowires

Data publikacji: 13 Dec 2017
Zakres stron: 643 - 654

Abstrakt

Abstract

– The results of research aimed at the gas sensing nanowires (NWs) engineering are presented. Structurally modulated SnO2 NWs were obtained at 900°C in the modified vapor-solid process, allowing that NW morphology could be encoded in a programmable way along its length. PVD technique was used for Ti/Au electrical contacts deposition and gas sensitive nanoscale chemiresistors formation.

Created nanostructures were characterized for their gas sensing performance. It was established that structurally-modulated NWs possess better gas sensitive characteristics in comparison with the straight ones. Obtained results are discussed from the positions of single-crystal “necks” formation in NWs.

Słowa kluczowe

  • Nanostructure
  • Tin dioxide
  • Nanowire
  • Chemoresistor
  • Structural modulation
  • Morphology
access type Otwarty dostęp

Model identification and Smart structural vibration Control using H controller

Data publikacji: 13 Dec 2017
Zakres stron: 655 - 671

Abstrakt

Abstract

A smart structure plays a vital role in aerospace applications and robotics and other applications. It presents many challenging control problems due to their non-linear dynamic behavior. The Objective of this work is to design a controller that minimizes the structural vibration using H∞ controller. Vibration as a measured parameter has been used to evaluate model of a nonlinear process (piezoelectric actuator and sensor) at different modes .The model was generated using an ARMAX technique. By selecting appropriate weighting functions H controller were designed based on mixed sensitivity approach using singular loop shaping method. The performance of H controller was compared with LQG controller based on vibration reduction. From the results it is observed that the H∞ controller is the best suited for smart structural process.

Słowa kluczowe

  • controller
  • ARMAX
  • smart structure
  • LQG
  • weighting function
  • loop shaping
  • weighting function
access type Otwarty dostęp

Review Of Wet Gas Flow Measurement Using Venturi Tubes And Radio Active Materials

Data publikacji: 13 Dec 2017
Zakres stron: 672 - 689

Abstrakt

Abstract

This paper introduces the application of Venturi flow meter for wet gas flow measurement. Wet gas which is a gas containing small amount of liquid is mostly encountered in gas wells where the extracted gas has water and condensate inside. Venturi flow meters which originally were introduced for single phase flow measurement are adapted for wet gas measurement. In this paper, we elaborate using of Venturi meter as a device for measuring wet gas flow and explain versatile methods for correcting the reading of Venturi tube for wet gas application. Tracer injection method is introduced as a manual tool for measuring water and condensate flow rate in wet gas fluid. Also radioactive measuring method has been introduced as an automatic method for measuring the ratio between gas, water and condensate in wet gas fluid. Finally different aspects of using radioactive sources are elaborated.

Słowa kluczowe

  • Wet gas
  • Flow measurement
  • Venturi
  • Radio-active densitometer
  • Multi phase flow measurement
access type Otwarty dostęp

A Coarse-to-Fine Approach for Remote-Sensing Image Registration Based on a Local Method

Data publikacji: 13 Dec 2017
Zakres stron: 690 - 702

Abstrakt

Abstract

Multispectral satellite imagery registration is a fundamental step for remote sensing applications such as global change detection, feature classification, and image fusion. Since image registration via the manual selection of control points is a repetitive and time-intensive task, a more efficient automatic coarse-to-fine algorithm for multispectral remote sensing image registration is proposed in this paper. First, for the coarse registration, the Haar Wavelet Transform (HWT) is adopted to produce lower-resolution levels of reference and input images; then, the Speeded Up Robust Features (SURF) algorithm is utilized for quickly searching for matching points. After the coarse registration is completed, the Harris operator is used to extract feature points, and initial correspondences are established using the normalized cross-correlation to achieve the fine registration. Second, in order to remove mismatched points, the RANdom SAmple Consensus (RANSAC) algorithm is applied to putative correspondences. Due to large amount of satellite image data available, we used block processing in the refined registration to increase the efficiency in memory use. Finally, the final transformation function is obtained via the local weighted mean method in order to deal with local geometric differences between the reference and input images. Compared to global registration by manually selecting the control points, the proposed method is fully automatic and computationally efficient. Experimental results with well-known data sets (Worldview-1,2 and Quickbird remote-sensing images) again demonstrate the accuracy and effectiveness of the proposed algorithm for multispectral remote-sensing image registration.

Słowa kluczowe

  • Multispectral satellite image
  • Image registration
  • SURF
  • RANSAC
access type Otwarty dostęp

Characterization Of Cracks And Delaminations Using Pwas Ad Lamb Wave Based Time-Frequency Methods

Data publikacji: 13 Dec 2017
Zakres stron: 703 - 735

Abstrakt

Abstract

Use of smart sensor technology along with intelligent signal processing plays a crucial role in the implementation and working of ultrasonic wave based damage detection system. In this work, the interaction of A0 Lamb mode with damages like crack and delamination are studied. Piezoelectric Wafer Active Sensors (PWAS) are used for generation of Lamb waves to detect damages in metal and composite structures. Experiments were conducted on aluminum plates to study the interaction of Lamb wave with crack oriented at different angles and on a titanium turbine blade of complex geometry with a fine surface crack. A geodesic based Lamb wave approach was employed to locate a crack in an aluminum plate. The existing geodesic algorithm is improved by replacing the Dijkstra’s algorithm with the accurate fast marching method. Further, the interactions of A0 mode with multiple layer delaminations in glass fiber epoxy composite laminates were studied. Spectral Finite Element Method (SFEM) is used for numerical simulation to validate the experimental results. Time-frequency analysis techniques, namely Wavelet Transform (WT) and Hilbert Huang transform (HHT) are used to study the experimental signals and their performances were compared. This study provides significant insight into the problem of identifying localized damages in the structure using integrated PWAS and dispersion of multi-frequency signal after they interact with different types of damage.

Słowa kluczowe

  • Lamb waves
  • PWAS
  • Time-frequency analysis
  • Composites
  • Geodesics
  • Spectral Finite element method
  • Wavelet transform
  • Hilbert-Huang transform
  • Delamination
access type Otwarty dostęp

Application Of Draw Wire Sensor In Position Tracking Of Electro Hydraulic Actuator System

Data publikacji: 13 Dec 2017
Zakres stron: 736 - 755

Abstrakt

Abstract

Draw-wire sensor is classified as a contact measurement method. This sensor is ideal for applications with large measuring ranges, small sensor dimensions and when a low cost solution is required. The objective of this research is to explain the application of a draw-wire sensor in position tracking of electro-hydraulic actuator system. The work started with the modeling of the electro hydraulic actuator system. Draw wire sensor is attached to the load of electro hydraulic system to measure its motion when an input signal is injected to the system. The sensor output is the displacement in millimeter and converted to the voltage based on the input signal given. These input and output readings are collected and applied to a system identification procedure in order to obtain the best mathematical model of the system. The modeling process is followed by designed a proportional integral and derivative controller (PID) for the system to assure the output is tracking the input given. The designed controller is applied to the system in both simulation and real time mode. The output performance of the system for these two modes is compared and it can be seen that the simulation and real-time output are almost similar. The overall process of this work shows the important role of draw wire sensor in capturing the output data of the electro hydraulic actuator system precisely either with or without controller. Other displacement transducer might be used in future work of position tracking of electro-hydraulic actuator system.

Słowa kluczowe

  • Electro-hydraulic actuator
  • draw wire sensor
  • system identification
  • ARX model
  • PID controller
access type Otwarty dostęp

Long-Reach Flying Functional Inkjet System By Employing Electrostatic Acceleration

Data publikacji: 13 Dec 2017
Zakres stron: 756 - 770

Abstrakt

Abstract

In this paper, the authors proposed a novel idea of a long-reach flying inkjet system employing electrostatically-accelerated ink drop for the purpose of functional ink micro pattern plotting by contact-free and environment friendly. Proposed working principle was demonstrated through experiment and analysis. At the 5-mm of electrode gap and φ 120 μm of nozzle, the applicable maximum voltage was 3.5kV realizing 67% up (1.67 times) of droplet flying velocity by one-step of accelerating. By φ 10 μm of droplet, over 35m/s of flying velocity was promising and by 2~3 steps of acceleratingfurther of speed increment could be expected.

Słowa kluczowe

  • long-reach
  • contact free
  • functional ink
  • direct wiring
  • micro pattern
  • coating film
access type Otwarty dostęp

Microcontroller based Power Efficient Signal Conditioning Unit for Detection of a Single Gas using MEMS based Sensor

Data publikacji: 13 Dec 2017
Zakres stron: 771 - 782

Abstrakt

Abstract

-A low power MEMS based sensor along with the embedded power efficient signal conditioning unit (Microcontroller based), which can be used with any suitable sensor-network to detect and quantify variations in a particular gas concentration, has been reported in this paper. The power consumption of the MEMS gas sensor is ~ 70mW to 100mW depending upon its operating temperature (150-250°C) and that of entire signal conditioning unit (consisting of low noise amplifier, switch, microcontroller and power management chip) is ~ 36mW in the ON state and only ~7.2μW in OFF state (sleep mode). The test gas in this particular case was methane for which sensor resistance varied from 100KΩ to 10KΩ. This hybrid sensor system is very much suitable for detecting a single gas with display of corresponding gas concentrations and subsequent alarming if the threshold limit is crossed.

Słowa kluczowe

  • MEMS
  • Gas sensor
  • Low power
  • Microcontroller
  • Signal Conditioning
access type Otwarty dostęp

System Identification Of Nonlinear Autoregressive Models In Monitoring Dengue Infection

Data publikacji: 13 Dec 2017
Zakres stron: 783 - 806

Abstrakt

Abstract

This paper proposes system identification on application of nonlinear AR (NAR) based on Artificial Neural Network (ANN) for monitor of dengue infections. In building the model, three selection criteria, i.e. the final prediction error (FPE), Akaike’s Information Criteria (AIC), and Lipschitz number were used. Each of the models is divided into two approaches, which are unregularized approach and regularized approach. The findings indicate that NARMAX model with regularized approach yields better accuracy by 80.60%. The best parameters’ settings for this thesis can be found using the Lipschitz number criterion for the model order selection with artificial neural network structure of 4 trained using the Levenberg Marquardt algorithm.

Słowa kluczowe

  • dengue fever
  • NAR model
  • AIC
  • Lipschitz
  • FPE
  • ROC and AUC
access type Otwarty dostęp

Nanosensors Engineering: Ii. Superficial Functionalization Of Sno2 Nanowire For Sensing Performance Improvement

Data publikacji: 13 Dec 2017
Zakres stron: 807 - 819

Abstrakt

Abstract

Paper presents results of study aimed the tin dioxide nanowire gas sensing performance improvement via in situ functionalization with NiO. Developed nanostructures have demonstrated improved by order gas sensitivity toward H2 and CO and drastic increase of selectivity to H2 against CO. Obtained results are discussed from the point of view of NiO/Sno2 heterojunction formation and its influence on electrical transport through nanowire and nanowire interaction with target gases.

Słowa kluczowe

  • Nanowire
  • tin dioxide
  • nickel oxide
  • chemoresistor
  • functionalization
  • heterojunction

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