• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.9
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• pp.1138-1143
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• 2020

MRI scans in the abdominal area are difficult to achieve optimal images due to artificial respiration. Among 45 patients (male:female = 30:15) who underwent abdominal MRI examination, a metronome-based examination method was studied for patients whose breathing is difficult and difficult to examine. The images examined without using a metronome were divided into group A, and the images examined using a metronome were divided into group B. Image quality improvement (30%) and inspection time (approximately 50 seconds) were reduced in images using metronome. During abdominal magnetic resonance imaging (ABD MRI), the images examined using a metronome had differences in quality and examination time compared to the unused images. It is more effective to use a metronome brace that controls the patient's respiratory rate during abdominal magnetic resonance imaging under respiratory induction in patients with difficulty in respiratory-gated.

• Journal of Internet Computing and Services
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• v.24 no.4
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• pp.85-92
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• 2023

Deep learning applications are increasingly being leveraged for disease detection tasks in medical imaging modalities such as X-ray, Computed Tomography (CT), and Magnetic Resonance Imaging (MRI). Most data-centric deep learning challenges necessitate the use of supervised learning methodologies to attain high accuracy and to facilitate performance evaluation through comparison with the ground truth. Supervised learning mandates a substantial amount of image and label sets, however, procuring an adequate volume of medical imaging data for training is a formidable task. Various data augmentation strategies can mitigate the underfitting issue inherent in supervised learning-based models that are trained on limited medical image and label sets. This research investigates the enhancement of a deep learning-based rib fracture segmentation model and the efficacy of data augmentation techniques such as left-right flipping, rotation, and scaling. Augmented dataset with L/R flipping and rotations(30°, 60°) increased model performance, however, dataset with rotation(90°) and ⨯0.5 rescaling decreased model performance. This indicates the usage of appropriate data augmentation methods depending on datasets and tasks.

• The Journal of Advanced Prosthodontics
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• v.15 no.3
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• pp.126-135
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• 2023

PURPOSE. The aim of this study was to evaluate the reliability of implant stability measuring devices depending on the location of the implant and the position of the patient. MATERIALS AND METHODS. Six implants were installed in different dentate sextants of six artificial bone models. Implant stability was measured in three conditions of the bone model (without mounting on a phantom head, mounted on a phantom head in supine position, and mounted on a phantom head in upright position). A resonance frequency analysis device (Osstell) and two damping capacity analysis devices (Periotest and Anycheck) were used to measure implant stability. The values measured outside the phantom head were treated as controls, and the values inside the phantom head were compared using an independent t-test. RESULTS. Osstell showed different results in two of the six divisions in both the supine and upright positions compared to outside of the mouth (P < .05). Periotest showed different results in all six parts in the supine position and in five parts in the upright position compared to outside of the mouth (P < .05). While Anycheck showed different results in five areas in the supine position compared to outside of the mouth, it showed different results in only one area in the upright position (P < .05). CONCLUSION. In the difficult implant position for the operator to access, the implant stability measuring devices show less reliability. The accessibility of implant is greatly affected in the order of Osstell, Anycheck, and Periotest.

• Journal of Dental Rehabilitation and Applied Science
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• v.23 no.4
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• pp.327-336
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• 2007

Purpose This study was planned to compare and evaluate the stability of implant using $Osstell^{TM}$ and Osstell $Mentor^{TM}$. Material and methods Artificial bone and RBM(resorbable blasting media) surface blasted implants(Osstem US II, SS II implants - diameter: 4mm, length: 13mm) were used. To measure the stability of installed implants, $Osstell^{TM}$ and Osstell $Mentor^{TM}$ were used. In the first experiment, five implants were installed in D1(external type implants) and D3(internal type implants). In the second experiment, 4 internal type implants were divided in two groups and installed in D1 artificial bone with different depth. In the third experiment, two external implants were installed in D1 and D3 artificial bone each and two internal implants were installed in D1 and D3 artificial bone. In all groups, their stability were measured by $Osstell^{TM}$ and Osstell $Mentor^{TM}$. Results In all groups, $Osstell^{TM}$ and Osstell $Mentor^{TM}$ both showed reliable measurement values. The value difference between $Osstell^{TM}$ and Osstell $Mentor^{TM}$ was observed but the difference was small and clinically acceptable. Conclusion These results suggest that the use of Osstell $Mentor^{TM}$ has clinical relevance in the assessment of implant stability.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.5
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• pp.613-623
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• 2012

In this paper, we present an ultra miniaturized voltage tuned oscillator, with HMIC-type amplifier and phase shifter, using LTCC artificial dielectric resonator. ADR which consists of periodic conductor patterns and stacked layers has a smaller size than a dielectric resonator. The design specification of ADR is obtained from the design goal of oscillator. The structure of the ADR with a stacked circular disk type is chosen. The resonance characteristic, physical dimension and stack number are analyzed. For miniaturization of ADRO, the ADR is internally implemented at the upper part of the LTCC substrate and the other circuits, which are amplifier and phase shifter are integrated at the bottom side respectively. The fabricated ADRO has ultra small size of $13{\times}13{\times}3mm^3$ and is a SMT type. The designed ADRO satisfies the open-loop oscillation condition at the design frequency. As a results, the oscillation frequency range is 2.025~2.108 GHz at a tuning voltage of 0~5 V. The phase noise is $-109{\pm}4$ dBc/Hz at 100 kHz offset frequency and the power is $6.8{\pm}0.2$ dBm. The power frequency tuning normalized figure of merit is -30.88 dB.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.5
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• pp.305-311
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• 2016

Induction heating is the process in which an electrically conducting object (usually a metal) is heated by electromagnetic induction through heat generated in the object by eddy currents. The main advantage of an induction heating device is the generation of the heat inside the target object itself. Hence, non-contact and safe heating devices are widely used in many industrial and medical fields. Recently, a new dental implant system was developed using a shape-memory alloy, wherein an artificial tooth could be easily removed from the dental implant by heating. This paper discusses the development of an induction-heating device to remove the dental crown in the new implant system. First, the finite element simulation of electromagnetic and thermal coupling analysis was implemented to obtain the temperature distributions of the target object for various frequencies, input currents, and coil shapes. Based on the simulation results, experiments were conducted by using prototypes, and an induction heating device was developed to remove the dental crown from the implant.

• Journal of Biomedical Engineering Research
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• v.41 no.6
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• pp.228-234
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• 2020

Superparamagnetic iron oxide nanoparticles (SPIONs) are approved by the Food and Drug Administration (FDA) in the United States. SPIONs are used in magnetic resonance imaging (MRI) as contrast agents and targeted delivery in nanomedicine using external magnet sources. SPIONs act as an artificial peroxidase (i.e., nanozyme), and these reactions were highly stable in various pH conditions and temperatures. In this study, we report a nanozyme ability of the clustered SPIONs (CSPIONs) synthesized by the oil-in-water (O/W) method and coated with biocompatible poly(lactic-co-glycolic acid) (PLGA). We hypothesize that the CSPIONs can have high sensitivity toward H2O2 derived from the reaction between a fixed amount of glucose and glucose oxidase (GOX). As a result, CSPIONs oxidized a 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS) commonly used as a substrate for hydrogen peroxidase in the presence of H2O2, leading to a change in the color of the substrate. We also utilized a colorimetric assay at 417 nm using various glucose concentrations from 5 mM to 1.25 μM to validate β-D-glucose detection. This study demonstrated that the absorbance value increases along with increasing the glucose level. The results were highly repeated at concentrations below 5 mM (all standard deviations < 0.03). Moreover, the sensitivity and limit of detection were 1.50 and 5.44 μM, respectively, in which CSPIONs are more responsive to glucose than SPIONs. In conclusion, this study suggests that CSPIONs have the potential to be used for glucose detection in diabetic patients using a physiological fluid such as ocular, saliva, and urine.

• Journal of Korean Port Research
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• v.14 no.3
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• pp.321-329
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• 2000

Welding is essential for the manufacture of a range of engineering components which may vary from very large structures such as ships and bridges to very complex structures such as aircraft engines, or miniature components for microelectronic applications. Especially, a domestic situation of the welding automation is still depend on the arc sensing system in comparison to the vision sensing system. Specially, the gap-detecting of workpiece using conventional arc sensor is proposed in this study. As a same principle, a welding current varies with the size of a welding gap. This study introduce to the fuzzy membership filter to cancel a high frequency noise of welding current, and ART2 which has the competitive learning network classifies the signal patterns the filtered welding signal. A welding current possesses a specific pattern according to the existence or the size of a welding gap. These specific patterns result in different classification in comparison with an occasion for no welding gap. The patterns in each case of 1mm, 2mm, 3mm and no welding gap are identified by the artificial neural network.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.165-170
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• 2004

The purpose of this work was to assess and quantify the beneficial effects of long-term gas exchange, at varying frequencies, for the development of a vibrating intravascular lung assistance device (VIVLAD), for patients suffering from acute respiratory distress syndrome (ARDS). The experimental design and procedure have been applied to the construction of a new device for assessing the effectiveness of membrane vibrations. An analytical solution has been developed for the hydrodynamics of flow through a bundle of sinusoidally vibrated hollow fibers, with the intention of gaining insight into how wall vibrations might enhance the performance of the VIVLAD. As a result, the maximum oxygen transfer rate was reached at the maximum amplitude and through the transfer of vibrations to the hollow fiber membranes. The device was excited by a frequency band of 7Hz at various water flow rates, as this frequency was the 2nd mode resonance frequency of the flexible beam. 675 hollow fiber membranes were also bundled, within the blood flow, into the device.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.714-717
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• 2007

In this study, a novel actuator was developed by employing the newly-synthesized ionic networking membrane (INM) of poly (styrene-alt-maleic anhydride) (PSMAn)-incorporated poly (vinylidene fluoride) (PVDF). Based on the same original membrane, various samples of INM actuator were prepared through different reduction times with the electroless-plating technique. The as-prepared INM actuators were tested in terms of surface resistance, platinum morphology, resonance frequency, tip displacement, current and blocked force, and their performance was compared to that of the widely-used traditional Nafion actuator. Scanning electron microscope (SEM) and transmission electron microscopy (TEM) revealed that much smaller and more uniform platinum particles were formed on the surfaces of the INM actuators as well as within their polymer matrix. Although excellent harmonic response was observed for the newly-developed INM actuators, this was found to be sensitive to the applied reduction times during the fabrication. The mechanical displacement of the INM actuator fabricated after optimum reduction times was much larger than that of its Nafion counterpart of comparable thickness under the stimulus of constant and alternating current voltage.