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Journal Details
Format
Journal
eISSN
1335-8871
First Published
07 Mar 2008
Publication timeframe
6 times per year
Languages
English

Search

Volume 13 (2013): Issue 4 (August 2013)

Journal Details
Format
Journal
eISSN
1335-8871
First Published
07 Mar 2008
Publication timeframe
6 times per year
Languages
English

Search

8 Articles
access type Open Access

Magnetic Resonance Imaging of Surgical Implants Made from Weak Magnetic Materials

Published Online: 24 Aug 2013
Page range: 165 - 168

Abstract

Materials with high magnetic susceptibility cause local inhomogeneities in the main field of the magnetic resonance (MR) tomograph. These inhomogeneities lead to loss of phase coherence, and thus to a rapid loss of signal in the image. In our research we investigated inhomogeneous field of magnetic implants such as magnetic fibers, designed for inner suture during surgery. The magnetic field inhomogeneities were studied at low magnetic planar phantom, which was made from four thin strips of magnetic tape, arranged grid-wise. We optimized the properties of imaging sequences with the aim to find the best setup for magnetic fiber visualization. These fibers can be potentially exploited in surgery for internal stitches. Stitches can be visualized by the magnetic resonance imaging (MRI) method after surgery. This study shows that the imaging of magnetic implants is possible by using the low field MRI systems, without the use of complicated post processing techniques (e.g., IDEAL).

Keywords

  • NMR imaging
  • field calculation
  • metal artifact
  • surgery implants
access type Open Access

Design, Investigation and Measurement of A Compact Ultra Wideband Antenna for Portable Applications

Published Online: 24 Aug 2013
Page range: 169 - 176

Abstract

The design of a printed compact planar antenna of asymmetrical structure with ultra wide bandwidth is described and investigated in this paper. The antenna provides more than 114% impedance bandwidth below VSWR 2 (from 3.3 to more than 12 GHz) with a center frequency of 7.65 GHz; thus it covers the bandwidth requirement for portable UWB wireless device applications. The structure of the asymmetric proposed antenna is very simple and composed of a small hexagonal shaped patch with two asymmetrical coplanar ground planes. It occupies an area of only 20 × 24.5 mm2 when printed on one side of an FR4 substrate with a thickness of 1.6 mm.

Keywords

  • Antenna measurement
  • ultra wideband technology
  • radiation patterns measurement
  • compact antenna system
  • microwave frequencies
  • surface current distribution
  • portable device applications
access type Open Access

A New Neutrosophic Approach of Wiener Filtering for MRI Denoising

Published Online: 24 Aug 2013
Page range: 177 - 186

Abstract

In this paper, a new filtering method based on neutrosophic set (NS) approach of wiener filter is presented to remove Rician noise from magnetic resonance image. A neutrosophic set, a part of neutrosophy theory, studies the origin, nature and scope of neutralities, as well as their interactions with different ideational spectra. Now, we apply the neutrosophic set into image domain and define some concepts and operators for image denoising. The image is transformed into NS domain, described using three membership sets: True (T), Indeterminacy (I) and False (F). The entropy of the neutrosophic set is defined and employed to measure the indeterminacy. The ω-wiener filtering operation is used on T and F to decrease the set indeterminacy and remove noise. The experiments have conducted on simulated Magnetic Resonance images (MRI) from Brainweb database and clinical MR images corrupted by Rician noise. The results show that the NS wiener filter produces better denoising results in terms of visual perception, qualitative and quantitative measures compared with other denoising methods, such as classical wiener filter, the anisotropic diffusion filter, the total variation minimization scheme and non local means filter.

Keywords

  • Denoising
  • Magnetic Resonance imaging
  • Neutrosophic Set
  • Rician distribution
  • wiener
access type Open Access

Decoupling Analysis of a Sliding Structure Six-axis Force/Torque Sensor

Published Online: 24 Aug 2013
Page range: 187 - 193

Abstract

This paper analyzes the decoupling of a sliding structure six-axis force/torque sensor, which is used to measure the interactive force between surgical tools and soft tissue for the establishment of soft-tissue force model. Because this decoupling structure requires accurate sliding clearance and symmetric grooves, the influence of contact force between the elastic body and the groove sidewall on decoupling is analyzed. The analysis results indicate that the contact force will produce additional coupling error. The robust design method of elastic body size optimization is used to eliminate the influence of contact force. In the calibration test, the expanded uncertainty of the calibration device is evaluated and the calibration results validate the good decoupling.

Keywords

  • Tool-tissue interactive force
  • force/torque sensor
  • sliding structure
  • decoupling
  • robust design
  • uncertainty
access type Open Access

Portable Light Pen 3D Vision Coordinate Measuring System- Probe Tip Center Calibration

Published Online: 24 Aug 2013
Page range: 194 - 199

Abstract

For different tasks, probe tip should be changed in the 3D vision coordinate measuring system and the accurate determination of probe tip center position is critical. A novel and simple approach for calibrating the probe tip center position of the light pen is presented in this paper. Hundreds of images of the light pen with different postures are collected while the probe tip is kept in firm contact with a reference conical hole. The probe tip position is determined by computing the rotation matrix and translation vector from the obtained images by using the least square fitting method. The experimental results demonstrate the effectiveness of the proposed approach. Its repeatability reaches 0.033 mm, 0.030 mm, and 0.043 mm in x, y, and z axes, respectively, and its convergence speed is satisfactory.

Keywords

  • Probe tip
  • center calibration
  • light pen
  • portable 3D vision coordinate measuring system
  • reference conical hole
access type Open Access

A Cross Unequal Clustering Routing Algorithm for Sensor Network

Published Online: 24 Aug 2013
Page range: 200 - 205

Abstract

In the routing protocol for wireless sensor network, the cluster size is generally fixed in clustering routing algorithm for wireless sensor network, which can easily lead to the “hot spot” problem. Furthermore, the majority of routing algorithms barely consider the problem of long distance communication between adjacent cluster heads that brings high energy consumption. Therefore, this paper proposes a new cross unequal clustering routing algorithm based on the EEUC algorithm. In order to solve the defects of EEUC algorithm, this algorithm calculating of competition radius takes the node’s position and node’s remaining energy into account to make the load of cluster heads more balanced. At the same time, cluster adjacent node is applied to transport data and reduce the energy-loss of cluster heads. Simulation experiments show that, compared with LEACH and EEUC, the proposed algorithm can effectively reduce the energy-loss of cluster heads and balance the energy consumption among all nodes in the network and improve the network lifetime

Keywords

  • Sensor networks
  • routing algorithm
  • energy balance
access type Open Access

Random Channel Generator for Indoor Power Line Communication

Published Online: 24 Aug 2013
Page range: 206 - 213

Abstract

The paper deals with creating an indoor power line model based on random parameters. This model approximates the real parameters of the power line communication with sufficient precision. A detailed analysis of earlier and current research in power line communication modelling, especially for power line models, is described. Measurement of transmission line parameters and power line model verification follows. Based on model analysis and load impedance measurement, a mathematical description of the model is designed. A reference model for different scenarios is realized too. The last part gives the analysis of this model and simulation results.

Keywords

  • Power line communication
  • linear time-invariant system
  • measurement
  • model
  • generator
  • transfer function
access type Open Access

Numerical Analysis of Influencing Factors and Capability for Thermal Wave NDT in Liquid Propellant Tank Corrosion Damage Detection

Published Online: 24 Aug 2013
Page range: 214 - 222

Abstract

Due to the disadvantages of traditional NDT methods for liquid propellant tank corrosion detection, Thermal Wave Nondestructive Testing (ITWNDT) technology was applied. The heat exchange process of thermal wave in corrosion tank was simulated by the numerical method. Parameters of TWNDT as the best detection time (tbest), the maximum surface temperature difference (ΔTmax), and the temperature difference holding time (τΔT>0.1) were discussed as the targets. Based on these parameters, factors influencing the detection results of tank materials, dressed liquid (also considered as the corrosion product), pit characters (depth and size), heat flux and thermal excitation time length (pulsed width), environmental conditions and other factors were analyzed. Simulation results show that ITWNDT can identify the defect depth, size and position rapidly and effectively. Material properties of the tank were influencing the tbest, ΔTmax and τΔT>0.1, while the dressed liquid, thermal excitation parameters and the conditions of environment do not influence the tbest. Pit characters of the depth and size have close relationship with tbest and ΔTmax, therefore, for a tank with certain material and certain liquid dressed in, the pit corrosion damage can be accurately evaluated.

Keywords

  • Liquid propellant tank
  • corrosion
  • infrared thermal wave detecting
  • influencing factors
  • numerical simulation
8 Articles
access type Open Access

Magnetic Resonance Imaging of Surgical Implants Made from Weak Magnetic Materials

Published Online: 24 Aug 2013
Page range: 165 - 168

Abstract

Materials with high magnetic susceptibility cause local inhomogeneities in the main field of the magnetic resonance (MR) tomograph. These inhomogeneities lead to loss of phase coherence, and thus to a rapid loss of signal in the image. In our research we investigated inhomogeneous field of magnetic implants such as magnetic fibers, designed for inner suture during surgery. The magnetic field inhomogeneities were studied at low magnetic planar phantom, which was made from four thin strips of magnetic tape, arranged grid-wise. We optimized the properties of imaging sequences with the aim to find the best setup for magnetic fiber visualization. These fibers can be potentially exploited in surgery for internal stitches. Stitches can be visualized by the magnetic resonance imaging (MRI) method after surgery. This study shows that the imaging of magnetic implants is possible by using the low field MRI systems, without the use of complicated post processing techniques (e.g., IDEAL).

Keywords

  • NMR imaging
  • field calculation
  • metal artifact
  • surgery implants
access type Open Access

Design, Investigation and Measurement of A Compact Ultra Wideband Antenna for Portable Applications

Published Online: 24 Aug 2013
Page range: 169 - 176

Abstract

The design of a printed compact planar antenna of asymmetrical structure with ultra wide bandwidth is described and investigated in this paper. The antenna provides more than 114% impedance bandwidth below VSWR 2 (from 3.3 to more than 12 GHz) with a center frequency of 7.65 GHz; thus it covers the bandwidth requirement for portable UWB wireless device applications. The structure of the asymmetric proposed antenna is very simple and composed of a small hexagonal shaped patch with two asymmetrical coplanar ground planes. It occupies an area of only 20 × 24.5 mm2 when printed on one side of an FR4 substrate with a thickness of 1.6 mm.

Keywords

  • Antenna measurement
  • ultra wideband technology
  • radiation patterns measurement
  • compact antenna system
  • microwave frequencies
  • surface current distribution
  • portable device applications
access type Open Access

A New Neutrosophic Approach of Wiener Filtering for MRI Denoising

Published Online: 24 Aug 2013
Page range: 177 - 186

Abstract

In this paper, a new filtering method based on neutrosophic set (NS) approach of wiener filter is presented to remove Rician noise from magnetic resonance image. A neutrosophic set, a part of neutrosophy theory, studies the origin, nature and scope of neutralities, as well as their interactions with different ideational spectra. Now, we apply the neutrosophic set into image domain and define some concepts and operators for image denoising. The image is transformed into NS domain, described using three membership sets: True (T), Indeterminacy (I) and False (F). The entropy of the neutrosophic set is defined and employed to measure the indeterminacy. The ω-wiener filtering operation is used on T and F to decrease the set indeterminacy and remove noise. The experiments have conducted on simulated Magnetic Resonance images (MRI) from Brainweb database and clinical MR images corrupted by Rician noise. The results show that the NS wiener filter produces better denoising results in terms of visual perception, qualitative and quantitative measures compared with other denoising methods, such as classical wiener filter, the anisotropic diffusion filter, the total variation minimization scheme and non local means filter.

Keywords

  • Denoising
  • Magnetic Resonance imaging
  • Neutrosophic Set
  • Rician distribution
  • wiener
access type Open Access

Decoupling Analysis of a Sliding Structure Six-axis Force/Torque Sensor

Published Online: 24 Aug 2013
Page range: 187 - 193

Abstract

This paper analyzes the decoupling of a sliding structure six-axis force/torque sensor, which is used to measure the interactive force between surgical tools and soft tissue for the establishment of soft-tissue force model. Because this decoupling structure requires accurate sliding clearance and symmetric grooves, the influence of contact force between the elastic body and the groove sidewall on decoupling is analyzed. The analysis results indicate that the contact force will produce additional coupling error. The robust design method of elastic body size optimization is used to eliminate the influence of contact force. In the calibration test, the expanded uncertainty of the calibration device is evaluated and the calibration results validate the good decoupling.

Keywords

  • Tool-tissue interactive force
  • force/torque sensor
  • sliding structure
  • decoupling
  • robust design
  • uncertainty
access type Open Access

Portable Light Pen 3D Vision Coordinate Measuring System- Probe Tip Center Calibration

Published Online: 24 Aug 2013
Page range: 194 - 199

Abstract

For different tasks, probe tip should be changed in the 3D vision coordinate measuring system and the accurate determination of probe tip center position is critical. A novel and simple approach for calibrating the probe tip center position of the light pen is presented in this paper. Hundreds of images of the light pen with different postures are collected while the probe tip is kept in firm contact with a reference conical hole. The probe tip position is determined by computing the rotation matrix and translation vector from the obtained images by using the least square fitting method. The experimental results demonstrate the effectiveness of the proposed approach. Its repeatability reaches 0.033 mm, 0.030 mm, and 0.043 mm in x, y, and z axes, respectively, and its convergence speed is satisfactory.

Keywords

  • Probe tip
  • center calibration
  • light pen
  • portable 3D vision coordinate measuring system
  • reference conical hole
access type Open Access

A Cross Unequal Clustering Routing Algorithm for Sensor Network

Published Online: 24 Aug 2013
Page range: 200 - 205

Abstract

In the routing protocol for wireless sensor network, the cluster size is generally fixed in clustering routing algorithm for wireless sensor network, which can easily lead to the “hot spot” problem. Furthermore, the majority of routing algorithms barely consider the problem of long distance communication between adjacent cluster heads that brings high energy consumption. Therefore, this paper proposes a new cross unequal clustering routing algorithm based on the EEUC algorithm. In order to solve the defects of EEUC algorithm, this algorithm calculating of competition radius takes the node’s position and node’s remaining energy into account to make the load of cluster heads more balanced. At the same time, cluster adjacent node is applied to transport data and reduce the energy-loss of cluster heads. Simulation experiments show that, compared with LEACH and EEUC, the proposed algorithm can effectively reduce the energy-loss of cluster heads and balance the energy consumption among all nodes in the network and improve the network lifetime

Keywords

  • Sensor networks
  • routing algorithm
  • energy balance
access type Open Access

Random Channel Generator for Indoor Power Line Communication

Published Online: 24 Aug 2013
Page range: 206 - 213

Abstract

The paper deals with creating an indoor power line model based on random parameters. This model approximates the real parameters of the power line communication with sufficient precision. A detailed analysis of earlier and current research in power line communication modelling, especially for power line models, is described. Measurement of transmission line parameters and power line model verification follows. Based on model analysis and load impedance measurement, a mathematical description of the model is designed. A reference model for different scenarios is realized too. The last part gives the analysis of this model and simulation results.

Keywords

  • Power line communication
  • linear time-invariant system
  • measurement
  • model
  • generator
  • transfer function
access type Open Access

Numerical Analysis of Influencing Factors and Capability for Thermal Wave NDT in Liquid Propellant Tank Corrosion Damage Detection

Published Online: 24 Aug 2013
Page range: 214 - 222

Abstract

Due to the disadvantages of traditional NDT methods for liquid propellant tank corrosion detection, Thermal Wave Nondestructive Testing (ITWNDT) technology was applied. The heat exchange process of thermal wave in corrosion tank was simulated by the numerical method. Parameters of TWNDT as the best detection time (tbest), the maximum surface temperature difference (ΔTmax), and the temperature difference holding time (τΔT>0.1) were discussed as the targets. Based on these parameters, factors influencing the detection results of tank materials, dressed liquid (also considered as the corrosion product), pit characters (depth and size), heat flux and thermal excitation time length (pulsed width), environmental conditions and other factors were analyzed. Simulation results show that ITWNDT can identify the defect depth, size and position rapidly and effectively. Material properties of the tank were influencing the tbest, ΔTmax and τΔT>0.1, while the dressed liquid, thermal excitation parameters and the conditions of environment do not influence the tbest. Pit characters of the depth and size have close relationship with tbest and ΔTmax, therefore, for a tank with certain material and certain liquid dressed in, the pit corrosion damage can be accurately evaluated.

Keywords

  • Liquid propellant tank
  • corrosion
  • infrared thermal wave detecting
  • influencing factors
  • numerical simulation

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