• Journal of Biomedical Engineering Research
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• v.27 no.5
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• pp.250-259
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• 2006

The information of eye movement is used in various fields such as psychology, ophthalmology, physiology, rehabilitation medicine, web design, HMI(human-machine interface), and so on. Various devices to detect the eye movement have been developed but they are too expensive. The general methods of eye movement tracking are EOG(electro-oculograph), Purkinje image tracker, scleral search coil technique, and video-oculograph(VOG). The purpose of this study is to embody the algorithm which tracks the location of the gazing point at a pupil. Two kinds of location data were compared to track the gazing point. One is the reference points(infrared LEDs) which is effected from the globe. Another is the center point of the pupil which is gained with a CCD camera. The reference point was captured with the CCD camera and infrared lights which were not recognized by human eyes. Both of images which were thrown and were not thrown an infrared light on the globe were captured and saved. The reflected reference points were detected with the brightness difference between the two saved images. In conclusion, the circumcenter theory of a triangle was used to look for the center of the pupil. The location of the gazing point was relatively indicated with the each center of the pupil and the reference point.

• Imaging Science in Dentistry
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• v.54 no.1
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• pp.43-48
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• 2024

Purpose: Oral hygiene, maintained through plaque control, helps prevent periodontal disease and dental caries. This study was conducted to examine the accuracy of plaque detection with an intraoral scanner(IOS) compared to images captured with an optical camera. Materials and Methods: To examine the effect of color tone, artificial tooth resin samples were stained red, blue, and green, after which images were acquired with a digital single-lens reflex (DSLR) camera and an IOS device. Stained surface ratios were then determined and compared. Additionally, the deviation rate of the IOS relative to the DSLR camera was computed for each color. In the clinical study, following plaque staining with red disclosing solution, the staining was captured by the DSLR and IOS devices, and the stained area on each image was measured. Results: The stained surface ratios did not differ significantly between DSLR and IOS images for any color group. Additionally, the deviation rate did not vary significantly across colors. In the clinical test, the stained plaque appeared slightly lighter in color, and the delineation of the stained areas less distinct, on the IOS compared to the DSLR images. However, the stained surface ratio was significantly higher in the IOS than in the DSLR group. Conclusion: When employing IOS with dental plaque staining, the impact of color was minimal, suggesting that the traditional red stain remains suitable for plaque detection. IOS images appeared relatively blurred and enlarged relative to the true state of the teeth, due to inferior sharpness compared to camera images.

• Journal of Biomedical Engineering Research
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• v.36 no.5
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• pp.169-176
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• 2015

Implantable closed-loop epilepsy controllers require ideally both accurate epileptic seizure detection and low power consumption. On-chip oscillators can be used in implantable devices because they consume less power than other oscillators such as crystal oscillators. In this study, we investigated the tolerable error range of a lower power on-chip oscillator without losing the accuracy of seizure detection. We used 24 ictal and 14 interictal intracranial electroencephalographic segments recorded from epilepsy surgery patients. The performance variations with respect to oscillator frequency errors were estimated in terms of specificity, modified sensitivity, and detection timing difference of seizure onset using Generic Osorio Frei Algorithm. The frequency errors of on-chip oscillators were set at ${\pm}10%$ as the worst case. Our results showed that an oscillator error of ${\pm}10%$ affected both specificity and modified sensitivity by less than 3%. In addition, seizure onsets were detected with errors earlier or later than without errors and the average detection timing difference varied within less than 0.5 s range. The results suggest that on-chip oscillators could be useful for low-power implantable devices without error compensation circuitry requiring significant additional power. These findings could help the design of closed-loop systems with a seizure detector and automated stimulators for intractable epilepsy patients.

• Polymer(Korea)
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• v.37 no.4
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• pp.411-419
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• 2013

Various biomaterials have been widely used for biomedical applications, including bio-organs, medical devices, and clinical devices like vessel, blood pumps, artificial kidneys and hearts, even in contact with blood. The issue of blood compatibility has been studied intensively to prevent negative effects such as thrombosis due to the implanted devices. The use of lotus-leaf-like structured surfaces has been extended to an increasing number of applications such as contamination prevention and anticorrosion applications. Various methods such as template, sol-gel transition, layer-by-layer, and other methods, developed for the fabrication of lotus-leaf-like surfaces have been reported for major industrial applications. Recently, the non-wettable character of these surfaces has been shown to be useful for biomedical applications ranging from blood-vessel replacement to antibacterial surface treatment. In this review, we provide a summary of current and future research efforts and opportunities in the development and medical applications of lotus-leaf-like structure surfaces.

• The Korean Journal of Health Service Management
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• v.10 no.3
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• pp.223-234
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• 2016

Objectives : The purpose of this study was to investigate accident cases involving electronic assistive devices, to determine how these accidents can be avoided and to devise preventative instructions for the handicapped who use these devices. Methods : This study was carried out from July 20 to October 3, 2015. A consent-based survey was conducted via mail and mobile phones targeting 700 electronic assistive device users, of which questionnaires from 290 users were collected and used in the analysis. Results : Accidents involving electronic assistive devices were investigated, especially the causes of the accidents and accident prevention education, as well as the status of the electronic assistive devices. The most common accident types were collision and falling, and it was found that the victims of the accidents usually suffered severe injury to their lower limbs. Most users used electronic assistive devices every day but rarely wore a safety belt because of discomfort. There were more incidents of collision and falling for older aged handicapped users, and the injury rate to the lower limbs was highest in handicapped elderly aged 50 years or older. Conclusions : In order to prevent accidents with electronic assistive devices in the future, a or management organizations must prepare specific safety guidelines and manage these accidents.

• Journal of the Korean Society of Safety
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• v.27 no.2
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• pp.92-97
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• 2012

Risk management is the process that helps to identify hazards, analyze them, and then to create an action plan to avoid and mitigate these hazards. The main objective of risk management in product development and manufacturing is to provide safe and efficient products without spending too many resources. Medical device manufacturers also face enormous risks - regulatory, legal, and financial - based on their products and processes, and the concepts of risk management are particularly important because any single failure may result in serious damages to body or loss of life. In this regard, a set of guidelines for the application of risk management to medical devices has been issued by ISO and specified in the document ISO 14971 Medical devices - Application of risk management to medical devices. The main objective of this study is to investigate the application of risk management to dental implant development and manufacturing processes based on ISO 14971. A general risk management process is first introduced, and the application of ISO 14971 to dental implants is further investigated.

• Science of Emotion and Sensibility
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• v.13 no.3
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• pp.581-596
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• 2010

The purposes of this study are to investigate and analyze the level of information and the state of digital divide of the disabled by surveying the demand for information and communication assistive devices, and to provide basic data for plans on the development and utilization of information and communication assistive devices. In order to understand the actual condition and the state of digital divide of persons with disabilities, the differences of possession and accessibility of information technology devices, usage ability, and utilization were analyzed according to the disability profile by using the T-test. The results show that there are significant differences (T=-2.510*) of possession and accessibility of information technology devices with respect to the disability profile, and that the disabled have lower possession and accessibility of devices than the non-disabled. Result of this study's demand forecast shows that about 28% of total respondents are currently using information and communication assistive devices, and a majority (67%) of them answered that the use of assistive devices lend great help to their lives. The proportion of those who have been supported by the government or related organizations with information and communication assistive devices were 36% of the total respondents, and those satisfied with the performance of the devices were 46% of the total responses. Meanwhile, only 36% of total users answered that the operation and use of functions of the devices was easy and convenient, responding that the difficulty of operating assistive devices was the greatest inconvenience. Moreover, the general requests of respondents in regards to the devices were stabilization of device performance, miniaturization of size, simplification of buttons, and reduction of weight.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.27-34
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• 2013

Most of existing biomedical signal measurement devices measure and evaluate biomedical signal only in a single device. Also, even if the device is multi-functional, those biomedical signals can be measured by selection of the user. In this paper, we implemented wristband-style biomedical signal measurement device for u-healthcare system to solve the problem above. Implemented device uses 4 infrared sensors to measure the pulse, 2 electrodes to measure the skin conductivity, and 3-axis accelerometer to measure momentum. Also, we propose a communication packet frame for transmitting biomedical signal data to PC or mobile device, using Zigbee. Studies show that our device has the error rate of less than twice for pulse measurement, 85.6%, 84.7% reliability for momentum measurement, and the skin conductivity has changed according to the user's physical status.

• Journal of Biomedical Engineering Research
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• v.30 no.5
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• pp.393-400
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• 2009

The present study developed a new technique with no physical object on the flow stream but enabling the air flow measurement and easily incorporated with the devices for cardiopulmonary resuscitation(CPR) procedure. A turbulence chamber was formed in the middle of the respiratory tube by locally enlarging the cross-sectional area where the flow related turbulence was generated inducing energy loss which was in turn converted into pressure difference. The turbulence chamber was simply an empty enlarged air space, thus no physical object existed on the flow stream, but still the flow rate could be evaluated. Computer simulation demonstrated stable turbulence formation big enough to measure. Experiment was followed on the proto-type transducer, the results of which were within ${\pm}5%$ error compared to the simulation data. Both inspiratory and expiratory flows were obtained with symmetric measurement characteristics. Quadratic curve fitting provided excellent calibration formula with a correlation coefficient>0.999(P<0.0001) and the mean relative error<1%. The present results can be usefully applied to accurately monitor the air flow rate during CPR.

• Journal of Biomedical Engineering Research
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• v.41 no.4
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• pp.165-171
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• 2020

In this study, it focuses on the development of radiographic devices for patellar imaging. On the previous X-ray examination of patella and patellofemoral joint, it analyzed the problems which could affect the results: unstable patients' pose, radiation exposure, and deterioration of image quality. The purpose of the research is to propose a future use of a developed device with an explanation of the process, function, and advantage of the device including the methods. The device is developed to focus on the diagnosis of the longitudinal and longitudinal fractures of the patella and patella/femoral joint, displacement such as dislocation, bone formation, stenosis of the patella/femorla joint, and cartilage wear. Due to the patient's anxious posture, it caused a shaking image, overlapping structures, and etcs, these factors challenge to diagnose accurately. In addition, the existing Settegast method and Hughston method, which are most frequently performed in the hospital field, are not suitable for the presence or absence of features or dislocation due to the heavy load on the patella of the patient. The developed device requires patients in a lying position and placing only their leg on the device, it increases the conveniences of the examination and decreases unnecessary radiation exposure of the patient except the patellar examination area. Moreover, one of the systems in the device fixes the detector, where the patients no longer need to hold the detector nor be in unstable posture, but describes the structure of the patella/femoral joint more clearly. Hoping the device will apply to more patients.