• Journal of Biomedical Engineering Research
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• v.41 no.5
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• pp.185-194
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• 2020

Arrhythmia is basically diagnosed with the electrocardiogram (ECG) signal, however, ECG is difficult to measure and it requires expert help in analyzing the signal. On the other hand, the radial pulse can be measured with easy and uncomplicated way in daily life, and could be suitable bio-signal for the recent untact paradigm and extensible signal for diagnosis of Korean medicine based on pulse pattern. In this study, we developed an irregular radial pulse detection algorithm based on a learning model and considered its applicability as arrhythmia screening. A total of 1432 pulse waves including irregular pulse data were used in the experiment. Three data sets were prepared with minimal preprocessing to avoid the heuristic feature extraction. As classification algorithms, elastic net logistic regression, random forest, and extreme gradient boosting were applied to each data set and the irregular pulse detection performances were estimated using area under the receiver operating characteristic curve based on a 10-fold cross-validation. The extreme gradient boosting method showed the superior performance than others and found that the classification accuracy reached 99.7%. The results confirmed that the proposed algorithm could be used for arrhythmia screening. To make a fusion technology integrating western and Korean medicine, arrhythmia subtype classification from the perspective of Korean medicine will be needed for future research.

• Korean Journal of Medicinal Crop Science
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• v.19 no.3
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• pp.198-204
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• 2011

This study was performed to enhance antifungal activity of anthracnose in chili pepper by nanopaticles of thiamine di-lauryl sulfate (TDS) through high pressure homogenization process. Yield of TDS was 79.14% by reaction of thiamine hydrochloride and sodium lauryl sulfate. TDS nanopaticle solution was manufactured through high pressure homogenization process. The turbidity of nanoparticles solution was increased with increasing the concentration of TDS, and nanoparticles solution of 100 ppm was showed the highest turbidity with absorbance of 3.212. The size of nanoparticles solution was measured as average 258.6 nm by DLS. Nanoparticles solution of 100 ppm showed growth inhibition activity with higher than about 80% compared to the control group against Colletotrichum gloeosporioides. Finally, nanoparticles solution was increased effectively the penetration of the TDS nanopaticles on attached cell membrane of hyphae and started to destruct the cells under microscope observation. Consequently, we suggested that the TDS nanoparticle solution by high pressure homogenization process might be suitable biochemical pesticides for improving the antifungal activities against anthracnose in pepper.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1589-1598
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• 2014

To support the WBAN, IEEE 802.15 Task Group 6 announced standardized documents on technical requirements of the PHY and MAC. In the IEEE 802.15.6 MAC protocol, CSMA/CA(Carrier Sense Multiple Access with Collision Avoidance) algorithm is performed based on the eight-level priorities according to the type of traffics of the periodic data from medical sensor nodes. Several nodes, which detected the changed bio signals, transmit emergency data at the same time, so latency could be higher than emergency latency and energy consumption will increase. In this thesis, we proposed a CSMA/CA algorithm in WBAN to solve these problems. Simulations are performed using a Castalia based on the OMNeT++ network simulation framework to estimate the performance of the proposed superframe and algorithms. Performance evaluation results show that the packet transmission success rate and energy efficiency are improved by reducing the probability of collision using the proposed MAC protocol.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.11
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• pp.1191-1198
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• 2011

The use of a ventricular assist device (VAD) can raise the one-year survival rate without cardiac transplantation from 25% to 52%. However, malfunction of the VAD system causes 6% of VAD patients' deaths, which could possibly be avoided through the development of new VADs in which VAD malfunctions do not affect the patient's heart movement or hemodynamic state. A conventional VAD has an impeller or vane for propelling blood that can allow blood to regurgitate when the propelling force is weaker than the aortic pressure. In this paper, we developed a new pulsatile conduit-shaped VAD that has two valves. This device removes the possibility of blood regurgitation and has a small stationary area even when the pumping force is extremely weak. We estimated the characteristics of the device by measuring the outflow and the pressure of the pump in in-vitro and in-vivo experiments.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.8 no.1
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• pp.57-66
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• 2014

This study has been conducted to identify the current status and practices of electrical stimulation for patients with dysphagia in Korea. Main goal of the study is to find evidences of developing and distributing a quality indicator and organized performance exam. This study analyzed 50 survey questionnaires given to clinical professionals in upper-scale general hospitals, university hospitals, nursing homes and professional rehabilitation hospitals. The survey sent out and collected by E-mails or interviews from August 21, 2013 to November 10, 2013. Most of the hospitals showed lack of using a quality indicator and organized performance exams in device maintenance, pre-operational tests and post-operational tests. It is strongly recommended to develop a standardized guideline of a higher quality indicator and organized performance exam in using neuromuscular electrical stimulator for patients who are suffering from dysphagia.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.335-338
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• 1996

We attempted to reconstruct basement membrane (BM) in between the epidermal compartment and dermal compartment in the artificial skin preparation and examine its effect on the skin architecture as well as on the epidermal differentiation. Laminin, one of the component of BM, stimulate the migration of the basal cells but type IV collagen which is a major component of the mechanical network of BM did not stimulate epidermal migration. However laminin in the presence of type IV collagen at a 1:1 molar ratio did not stimulate epidermal migration but provide nice demarcation between epidermis and dermis. This mixture of laminin and type IV collagen enhanced epidermal differentiation in the artificial skin based on the morphological observation as well as biochemical criteria. The epidermal acquirement of migratory ability on the laminin-rich substrate suggest that this type of unbalance in the expression of the components of BM may prevail in the area of healing tissue and the invasive transition of the tumor. The result in this study provide the technical improvement in the artificial skin preparation and further application of this technique for the reconstruction of other bio-artificial organ.

• Food Engineering Progress
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• v.13 no.4
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• pp.326-334
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• 2009

Blood coagulation and aggregation of platelet are crucial events in the pathogenesis of various ischemic diseases. The substance which can prevent blood coagulation and platelet aggregation was extracted from wood ear mushroom (Auricularia auricular-judae) and its anticoagulation activity was investigated. The dried A. auricular-judae was extracted with 0.1 N NaOH and its supernatant was further extracted with methanol and ethanol followed by $H_{2}O$. The resulting methanol soluble fraction showed significant antithrombotic activity in activated partial thromboplastin time, thrombin time, and prothrombin time assays with values of 100, 124, and 54 sec, respectively. This active substance was purified with DEAE-Sepharose CL6B and Sephacryl 400-HR and was found to be polysaccharide with the average molecular weight of over 150 kDa. This polysaccharide was xyloglucomannan of which the main component was mannose, and its anticoagulant activity was mostly mediated by inhibition of thrombin activity.

• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1417-1427
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• 2019

In this study, we evaluated the performance of a commercial pixelated cadmium zinc telluride (CZT) detector for spectroscopy and identified its feasibility as a Compton camera for radiation monitoring in a nuclear power plant. The detection system consisted of a $20mm{\times}20mm{\times}5mm$ CZT crystal with $8{\times}8$ pixelated anodes and a common cathode, in addition to an application specific integrated circuit. The performance of the various radioisotopes $^{57}Co$, $^{133}Ba$, $^{22}Na$, and $^{137}Cs$ was evaluated. In general, the amplitude of the induced signal in a CZT crystal depends on the interaction position and material non-uniformity. To minimize this dependency, a drift time correction was applied. The depth of each interaction was calculated by the drift time and the positional dependency of the signal amplitude was corrected based on the depth information. After the correction, the Compton regions of each spectrum were reduced, and energy resolutions of 122 keV, 356 keV, 511 keV, and 662 keV peaks were improved from 13.59%, 9.56%, 6.08%, and 5%-4.61%, 2.94%, 2.08%, and 2.2%, respectively. For the Compton imaging, simulations and experiments using one $^{137}Cs$ source with various angular positions and two $^{137}Cs$ sources were performed. Individual and multiple sources of $^{133}Ba$, $^{22}Na$, and $^{137}Cs$ were also measured. The images were successfully reconstructed by weighted list-mode maximum likelihood expectation maximization method. The angular resolutions and intrinsic efficiency of the $^{137}Cs$ experiments were approximately $7^{\circ}-9^{\circ}$ and $5{\times}10^{-4}-7{\times}10^{-4}$, respectively. The distortions of the source distribution were proportional to the offset angle.

• Journal of Practical Engineering Education
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• v.16 no.4
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• pp.491-497
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• 2024

Over the past five years, the proportion of patients with arrhythmia heart disease among teenagers and those in their 20s has been increasing. Heart disease has consistently remained the second leading cause of death in Korea and as the number has increased, electrocardiogram testing for arrhythmia has become important. However, specialized electrocardiogram medical devices are economically burdensome and are difficult to store individually in hospitals due to their large size and difficulty in operation. Testing is conducted through visits. Therefore, it is essential to enable individuals to perform ECG self-examinations using an Arduino-based ECG sensor that is affordable and easy to use in daily life, so that arrhythmia can be identified through individual ECG measurement. In this study, data is measured using an electrocardiogram sensor (AD8232), and changes in bio signals are visually provided through real-time monitoring, allowing users to make intuitive decisions and at the same time understand test results. To safeguard sensitive personal information, we have developed a web service that provides individual heart disease and customized health guides that can protect personal information through web vulnerability security using session and user authentication and SSL.

• Journal of radiological science and technology
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• v.41 no.5
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• pp.493-504
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• 2018

The diagnostic radiation equipment is managed in accordance with the "Rules for Safety Management of Diagnostic Radiation Equipment" enacted in 1995. The equipments should be inspected before use and every three years after use in accordance with the [Appendix 1] of the same rule. The inspection standard has been maintained without particular revision since enacted. But, over the past two decades new types of equipments have been manufactured and used. So, it is necessary to revise [Appendix 1] by making inspection items and inspection standards. In this study, we revised the classification system of equipments and reviewed international standards of IEC 60601 series, IEC 61223 series and AAPM TG 18 On-line Report No.03. And identified the problem of current inspection standards. Through this, we revised, deleted and added the inspection items and inspection standard of each equipment to meet the domestic circumstances. As a result of the study, we reorganized the classification system of equipment which are current classified as 5 classes into 22 classes as X-ray system etc. (7 classes), CT system etc. (5 classes) and Dental X-ray system etc. (10 classes). And then, we developed 70 inspection items for 6 types of equipments according to the reorganized classification system of equipments. The inspection items and inspection standards derived from this study have been proposed to the KCDC and will be applied to the revision of the Rule's [Appendix 1]. Therefore, we expect to be used as reference materials for domestic medical center, inspection institutions, and equipment manufacturing import companies.