Ki-Young Shin - Academia.edu (original) (raw)

Papers by Ki-Young Shin

Sensors, 2022

One of the major challenges for blind and visually impaired (BVI) people is traveling safely to c... more One of the major challenges for blind and visually impaired (BVI) people is traveling safely to cross intersections on foot. Many countries are now generating audible signals at crossings for visually impaired people to help with this problem. However, these accessible pedestrian signals can result in confusion for visually impaired people as they do not know which signal must be interpreted for traveling multiple crosses in complex road architecture. To solve this problem, we propose an assistive system called CAS (Crossing Assistance System) which extends the principle of the BLE (Bluetooth Low Energy) RSSI (Received Signal Strength Indicator) signal for outdoor and indoor location tracking and overcomes the intrinsic limitation of outdoor noise to enable us to locate the user effectively. We installed the system on a real-world intersection and collected a set of data for demonstrating the feasibility of outdoor RSSI tracking in a series of two studies. In the first study, our go...

Journal of Nanomaterials, 2019

Quantum dot (QD) is a kind of semiconductor nanoparticle and shows photoluminescence, in which th... more Quantum dot (QD) is a kind of semiconductor nanoparticle and shows photoluminescence, in which the light with narrow spectral band is emitted from the QD after the absorption of the excitation light. In this study, it is demonstrated that the LED-based light source combined with a QD film can be applied to spectral imaging. The polymer film with QD was prepared by photopolymerization. Through measurement of the emission spectrum, it was confirmed that the optical intensity at the peak wavelength of the spectral bands of 410 and 540 nm could be controlled by changing the thickness of the film. In the study using a home-made phantom mimicking blood vessels, the patterns’ contrast in the phantom images could be enhanced by using LED combined with QD as compared with the white light image. The LED light combined with the QD film provides a useful solution for illumination for spectral imaging.

The Journal of Korea Institute of Information, Electronics, and Communication Technology, 2016

World Health Organization reported that heart-related diseases such as coronary artery stenoses s... more World Health Organization reported that heart-related diseases such as coronary artery stenoses show the highest occurrence rate which may cause heart attack. Using Computed Tomography angiography images will allow radiologists to detect and have intervention by creating 3D roadmapping of the vessels. However, it is often complex and difficult do reconstruct 3D vessel which causes very large amount of time and previous researches were studied to segment vessels more accurate automatically. Therefore, in this paper, Region Competition, Geodesic Active Contour (GAC), Multi-atlas based segmentation and Active Shape Model algorithms were applied to segment aortic root from CTA images and the results were analyzed by using mean Hausdorff distance, volume to volume measure, computational time, user-interaction and coronary ostium detection rate. As a result, Extracted 3D aortic model using GAC showed the highest accuracy but also showed highest user-interaction results. Therefore, it is important to improve automatic segmentation algorithm in future

Journal of Nanomaterials, 2015

A microfluidic device was implemented to detect the enzymatic reaction of botulinum toxin A (BTA)... more A microfluidic device was implemented to detect the enzymatic reaction of botulinum toxin A (BTA) using Förster resonance energy transfer (FRET). The microfluidic device comprised a main channel having two loading zones, a reaction chamber and a side channel perpendicular to the main channel. The reaction chamber defined by weir in the main channel was packed with microbeads. The movement of the peptide substrate and the BTA in the microfluidic device was controlled by electrophoresis, and the enzymatic reaction of the BTA was detected through the changes of the fluorescence intensity in the reaction chamber. As a result, it was observed that the enzymatic reaction was affected by the electric voltage applied for the movement of the BTA and the peptide and improved by packing the microbeads in the reaction chamber. The microfluidic device provides the tool to investigate the proteolysis of the substrate by the BTA.

Dual-resolution image reconstruction for region-of-interest CT scan

Journal of Instrumentation, 2014

ABSTRACT In ordinary CT scan, so called full field-of-view (FFOV) scan, in which the x-ray beam s... more ABSTRACT In ordinary CT scan, so called full field-of-view (FFOV) scan, in which the x-ray beam span covers the whole section of the body, a large number of projections are necessary to reconstruct high resolution images. However, excessive x-ray dose is a great concern in FFOV scan. Region-of-interest (ROI) scan is a method to visualize the ROI in high resolution while reducing the x-ray dose. But, ROI scan suffers from bright-band artifacts which may hamper CT-number accuracy. In this study, we propose an image reconstruction method to eliminate the band artifacts in the ROI scan. In addition to the ROI scan with high sampling rate in the view direction, we get FFOV projection data with much lower sampling rate. Then, we reconstruct images in the compressed sensing (CS) framework with dual resolutions, that is, high resolution in the ROI and low resolution outside the ROI. For the dual-resolution image reconstruction, we implemented the dual-CS reconstruction algorithm in which data fidelity and total variation (TV) terms were enforced twice in the framework of adaptive steepest descent projection onto convex sets (ASD-POCS). The proposed method has remarkably reduced the bright-band artifacts at around the ROI boundary, and it has also effectively suppressed the streak artifacts over the entire image. We expect the proposed method can be greatly used for dual-resolution imaging with reducing the radiation dose, artifacts and scan time.

Journal of the Institute of Electronics and Information Engineers, 2016

This study evaluates the performance of image to patient registration algorithm by using stereo v... more This study evaluates the performance of image to patient registration algorithm by using stereo vision and CT image for facial region surgical navigation. For the process of image to patient registration, feature extraction and 3D coordinate calculation are conducted, and then 3D CT image to 3D coordinate registration is conducted. Of the five combinations that can be generated by using three facial feature extraction methods and three registration methods on stereo vision image, this study evaluates the one with the highest registration accuracy. In addition, image to patient registration accuracy was compared by changing the facial rotation angle. As a result of the experiment, it turned out that when the facial rotation angle is within 20 degrees, registration using Active Appearance Model and Pseudo Inverse Matching has the highest accuracy, and when the facial rotation angle is over 20 degrees, registration using Speeded Up Robust Features and Iterative Closest Point has the highest accuracy. These results indicate that, Active Appearance Model and Pseudo Inverse Matching methods should be used in order to reduce registration error when the facial rotation angle is within 20 degrees, and Speeded Up Robust Features and Iterative Closest Point methods should be used when the facial rotation angle is over 20 degrees.

SpringerPlus, 2013

In traditional Chinese and Korean medicine, doctors first observe a patient's pulse by gently... more In traditional Chinese and Korean medicine, doctors first observe a patient's pulse by gently and strongly pressing their fingers onto the wrist, and then make a diagnosis based on the observed pulse waves. The most common method to implement this diagnostic technique is to mechanically extract the pulse waves by applying a fixed range of pressures for all patients. However, this method does not consider the patients individual characteristics such as age, sex, and skin thickness. In the present study, we propose a new method of pulse wave extraction that incorporates the personal characteristics of the patients. This method measures the pulse wave signal at varying hold-down pressures, rather than applying a fixed hold-down pressure for all patients. To compare this new technique with existing methods, we extracted pulse waves from 20 subjects, and then determined the actual applied pressure at each step, the coefficient of floating and sinking pulse (CFS), and the distinction ...

Sensors (Basel, Switzerland), Jan 4, 2013

Several RPT sensors have been developed to acquire objective and quantitative pulse waves. These ... more Several RPT sensors have been developed to acquire objective and quantitative pulse waves. These sensors offer improved performance with respect to pressure calibration, size and sensor deployment, but not temperature. Since most pressure sensors are sensitive to temperature, various temperature compensation techniques have been developed, but these techniques are largely inapplicable to RPT sensors due to the size restrictions of the sensor, and incompatibility between the compensation techniques and the RPT sensor. Consequently, in this paper a new RPT sensor comprising six piezoresistive pressure sensors and one thermistor has been developed through finite element analysis and then a suitable temperature compensation technique has been proposed. This technique compensates for temperature variations by using the thermistor and simple compensation equations. As verification of the proposed compensation technique, pulse waves of all types were successfully compensated for temperatur...

Journal of the Institute of Electronics and Information Engineers, 2014

One in every 10 persons suffer from chronic gastritis in Korea. Endoscopy is most commonly used t... more One in every 10 persons suffer from chronic gastritis in Korea. Endoscopy is most commonly used to diagnose the chronic gastritis. Endoscopic diagnosis is precise but it is accompanied with pain and high cost. According to pulse diagnosis in Traditional East Asian Medicine, health problems in stomach can be diagnosed with radial pulse signals in 'Guan' location in the right wrist, which are non-invasive and cost-effective. In this study, we developed a classification model of chronic gastritis using pulse signals in right 'Guan' location. We used both linear discrimination method and logistic regression model with respect to pulse features obtained with a peak-valley detection algorithm and a Gaussian model. As a result, we obtained sensitivity ranged between 77%∼89% and specificity ranged between 72%∼83% depending on classification models and feature extraction methods, and the average classification rates were approximately 80%, irrespective of the models. Specifically, the Gaussian model were featured by superior sensitivities (89.1% and 87.5%) while the peak-valley detection method showed superior specificities (82.8% and 81.3%), and the average classification rate (sensitivity + specificity) of the Gaussian model was 80.9% which was 1.2% ahead of the peak-valley method. In conclusion, we obtained a reliable classification model for the chronic gastritis based on the radial pulse feature extraction algorithms, where the Gaussian model was featured by outperformed sensitivity and the peak-valley method was featured by outperformed specificity.

Computers in biology and medicine, Jan 27, 2015

Ultrasonic surgical units (USUs) have the advantage of minimizing tissue damage during surgeries ... more Ultrasonic surgical units (USUs) have the advantage of minimizing tissue damage during surgeries that require tissue dissection by reducing problems such as coagulation and unwanted carbonization, but the disadvantage of requiring manual adjustment of power output according to the target tissue. In order to overcome this limitation, it is necessary to determine the properties of in vivo tissues automatically. We propose a multi-classifier that can accurately classify tissues based on the unique impedance of each tissue. For this purpose, a multi-classifier was built based on single classifiers with high classification rates, and the classification accuracy of the proposed model was compared with that of single classifiers for various electrode types (Type-I: 6mm invasive; Type-II: 3mm invasive; Type-III: surface). The sensitivity and positive predictive value (PPV) of the multi-classifier by cross checks were determined. According to the 10-fold cross validation results, the classif...