• Transactions of Materials Processing
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• v.24 no.5
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• pp.368-374
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• 2015

Hydroforming of a non-axisymmetric thin-walled tubular component with variable cross sections was analyzed. In order to solve the sealing problem which occurred due to the thin and non-axisymmetric shape, the use of a lead patch on the punch, which had been successful in hydroforming of thin tubes, was evaluated. A lead patch was attached to the punch to solve the sealing problem, which was caused by the stress gradient in the non-axisymmetric shape. FEM and experiments were also performed to analyze these sealing problems associated with the punch shape and non-axisymmetric shape. Finally, the lead patch was attached at tube surface where intensive local strain concentration would occur to enhance the hydroformability. These methods were successfully used to fabricate non-axisymmetric thin-walled tubular component with variable cross sections that had previously failed during traditional hydroforming.

• Journal of Biomedical Engineering Research
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• v.27 no.2
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• pp.64-72
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• 2006

The present study introduces a new cortical patch-based source model for EEG/MEG cortical source imaging to consider anatomical constraints more precisely. Conventional source models for EEG/MEG cortical source imaging have used coarse cortical surface mesh or sampled small number of vertices from fine surface mesh, and thus they failed to utilize full anatomical information which nowadays we can get with sub-millimeter modeling accuracy. Conventional ones placed a single dipolar source on each cortical patch and estimated its intensity by means of various inverse algorithms; whereas the suggested cortical patch-based model integrates whole cortical area to construct lead field matrix and estimates current density that is assumed to be constant in each cortical patch. We applied the proposed and conventional models to realistic EEG data and compared the results quantitatively. The quantitative comparisons showed that the proposed model can provide more precise spatial descriptions of neuronal source distribution.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.1
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• pp.43-52
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• 2014

P-wave characteristic in the human electrocardiogram (ECG) is important in the diagnosis of atrial conduction pathology. In this paper, we measured an ECG signal from patient with cardiovascular disease using one lead ECG electrode system which is based on the wireless cardiac monitoring system. And we detected a P-wave in ECG signal using the complex-valued continuous wavelet transforms (CWT) according to two kinds of patch type electrodes such as an existing narrow patch type electrode and the improved wide patch type electrode presented in this paper. Also, we compared the characteristics in detecting the P-wave in terms of the magnitude and the width of P-waves. From the results of comparison we found that the width and the magnitude of P-wave detected using the wide patch type electrode is improved to be interpreted easier compared to those using the narrow patch type electrode. Furthermore, we have also proven that the complex-valued CWT can be used as a robust detector for P-wave in ECG signal analysis.

• Structural Engineering and Mechanics
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• v.59 no.1
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• pp.123-132
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• 2016

Many military and commercial aging aircrafts flying beyond their design life may experience severe crack and corrosion damage, and thus lead to catastrophic failures. In this paper, were used in a finite element model to evaluate the effect of corrosion on the adhesive damage in bonded composite repair of aircraft structures. The damage zone theory was implemented in the finite element code in order to achieve this objective. In addition, the effect of the corrosion, on the repair efficiency. Four different patch shapes were chosen to analyze the adhesive damage: rectangular, trapezoidal, circular and elliptical. The modified damage zone theory was implemented in the FE code to evaluate the adhesive damage. The obtained results show that the adhesive damage localized on the level of corrosion and in the sides of patch, and the rectangular patch offers high safety it reduces considerably the risk of the adhesive failure.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.2
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• pp.687-701
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• 2020

In the production of industrial fabric, it needs automatic real-time system to detect defects on the fabric for assuring the defect-free products flow to the market. At present, many visual-based methods are designed for detecting the fabric defects, but they usually lead to high false alarm. Base on this reason, we propose a Sobel operator combined with patch statistics (SOPS) algorithm for defects detection. First, we describe the defect detection model. mean filter is applied to preprocess the acquired image. Then, Sobel operator (SO) is applied to deal with the defect image, and we can get a coarse binary image. Finally, the binary image can be divided into many patches. For a given patch, a threshold is used to decide whether the patch is defect-free or not. Finally, a new image will be reconstructed, and we did a loop for the reconstructed image to suppress defects noise. Experiments show that the proposed SOPS algorithm is effective.

• Smart Structures and Systems
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• v.13 no.4
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• pp.547-565
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• 2014

This paper investigates the design of a perfect point load actuator based on flat triangular piezoelectric patches. Applying a difference of electric potential between the electrodes of a triangular patch leads to point loads at the tips and distributed moments along the edges of the electrodes. The previously derived analytical expressions of these forces show that they depend on two factors: the width over height (b/l) ratio of the triangle, and the ratio of the in-plane piezoelectric properties ($e_{31}/e_{32}$) of the active layer of the piezoelectric patch. In this paper, it is shown that by a proper choice of b/l and of the piezoelectric properties, the moments can be cancelled, so that if one side of the triangle is clamped, a perfect point load actuation can be achieved. This requires $e_{31}/e_{32}$ to be negative, which imposes the use of interdigitated electrodes instead of continuous ones. The design of two transducers with interdigitated electrodes for perfect point load actuation on a clamped plate is verified with finite element calculations. The first design is based on a full piezoelectric ceramic patch and shows superior actuation performance than the second design based on a piezocomposite patch with a volume fraction of fibres of 86%. The results show that both designs lead to perfect point load actuation while the use of an isotropic PZT patch with continuous electrodes gives significantly different results.

• Journal of Satellite, Information and Communications
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• v.10 no.3
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• pp.22-25
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• 2015

This paper performs Color Code Control Connected with Sound Source and Sensitivity of PA Speaker facility attachable LED patch. PA speaker delivers the technology to control the color code of LED patch along the present PA speakers for the facility-attached, LED the development of the patch. PA speakers facility attachable color code control technology of LED patch detects the sound from the PA speaker using a check, and if the analog signal source is detected (sound source)by converting the digital signal passes to the main controller can control the color and pattern of LED patches. In this paper, based on the PA speakers LED color control system, sound emotional linkage-type, and follow the lead of the PA speakers through the feelings can effectively channel LED linked to the source type and proceed to experiment with color and emotion control, whether or not they offer via the color control technology LED patch availability. PA speaker facility attachble color code control technology of LED patch connected with the source and future research directions in the field, and as the application is expected to be able to be widely utilized.

• Structural Engineering and Mechanics
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• v.7 no.2
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• pp.203-216
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• 1999

A previously proposed finite element formulation method is refined and modified to generate a new type of elements. The method is based on selecting a set of general solution modes for element formulation. The constant strain modes and higher order modes are selected and the formulation method is designed to ensure that the element will pass the basic single element test, which in turn ensures the passage of the basic patch test. If the element is to pass the higher order patch test also, the element stiffness matrix is in general asymmetric. The element stiffness matrix depends only on a nodal displacement matrix and a nodal force matrix. A symmetric stiffness matrix can be obtained by either modifying the nodal displacement matrix or the nodal force matrix. It is shown that both modifications lead to the same new element, which is demonstrated through numerical examples to be more robust than an assumed stress hybrid element in plane stress application. The method of formulation can also be used to arrive at the conforming displacement and hybrid stress formulations. The convergence of the latter two is explained from the point of view of the proposed method.

• The Korean Journal of Pain
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• v.31 no.2
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• pp.80-86
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• 2018

The Epidural blood patch is considered the gold standard for managing postdural puncture headache when supportive measures fail. However, it is a procedure which can lead to another inadvertent dural puncture. Other potential adverse events that could occur during a blood patch are meningitis, neurological deficits, and unconsciousness. The bilateral greater occipital nerve block has been used for treating chronic headaches in patients with PDPH with a single injection. This minimally invasive, simple procedure can be considered for patients early, along with other supportive treatment, and an epidural blood patch can be avoided.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.5 s.347
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• pp.147-155
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• 2006

In this paper, we propose a new Mushroom-like PBG concepts for designing with forbidden frequency band-gap at low frequency. These design rules are based on enhancing the capacitance per unit area using modified top-patch of mushroom PBG with no increase on the overall thickness of the substrate board. Also, in this paper, a new approach to suppress the surface wave from antenna is proposed by embedding compact mushroom PBG in the substrate. Comparisons between the results from a conventional patch antenna to a patch antenna on a PBG substrate show that the reduction in the surface wave level is remarkable. This can be observed in the radiation pattern and the maximum gain. The maximum gain for reference patch antenna is $6.43dB{\imath}$ at 5.37 GHz, while the maximum gain for the patch antenna with normal mushroom and vane mushroom PBG is $7.24dB{\imath}\;and\;7.53dB{\imath}$at 5.14 GHz. The back radiation is also considerably reduced; this will lead, of course, to an increase in the antenna efficiency.