• The Journal of the Acoustical Society of Korea
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• v.27 no.6
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• pp.263-270
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• 2008

The performance of an ultrasonic array sensor is determined by the properties of constituent materials and the effects of many structural parameters. In this study, with the finite element method, variation of the performances of an ultrasonic array sensor was analyzed in relation to its structural variables. Based on the analysis result, the structure of the ultrasonic array sensor was optimized to provide the highest sensitivity while satisfying such requirements as fractional bandwidth, center frequency and -20 dB pulse length. The optimization was carried out with the SQP-PD method for a target function composed of the ultrasonic array sensor performance. The optimized ultrasonic array sensor satisfied all the required specifications to be applicable to medical imaging diagnosis. The design technology in this paper can be utilized for other ultrasonic array sensors of a similar structure.

• Journal of Oriental Neuropsychiatry
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• v.31 no.2
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• pp.89-99
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• 2020

Objectives: The purpose of this study was to identify the needs of bio-signal devices for the diagnosis, assessment, and analysis of neurocognitive disorder in Korean medicine (KM) hospitals and clinics. Methods: A questionnaire was developed to survey the current status of medical device use, and diagnosis and interventions for patients with cognitive disorders in KM hospitals and clinics. November 11~December 2, 2019, 114 responses (71.9% completed) were collected by internet-based questionnaires from the members of the Korean society of Oriental Neuropsychiatry. Results: The clinical requests were in the descending order of hematology analyzer, ultrasound imaging system, and electroencephalography among the 15 most commonly used devices of which research would support for their clinical usability. The biosignal-based devices showed the highest research demands for patients with mild cognitive impairment rather than more severe stages of cognitive impairment. Prevention rather than diagnosis, or several treatment regimens was the strongest clinical area of the KM for patients with neurodegenerative cognitive impairment. Many responded that five to 10 minutes of test duration and 20,000 won to 30,000 won of cost would be appropriated for a new device to be developed. Conclusions: There were strong demands for the development of bio-signal devices for neurocognitive disorders among the KM doctors. Specifically, it showed high needs for the technology that can be used in the prevention area of cognitive disorders. Additionally, new medical devices to assess cognitive functions and to obtain KM pattern-related information were the high needs.

• Journal of Physiology & Pathology in Korean Medicine
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• v.33 no.3
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• pp.163-168
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• 2019

In order to enhance the 8 principle pattern diagnosis rate comparing with diagnostic method by self-report questionnaire on cold/heat pattern in the clinical practice, a new diagnostic method using form-color-pulse-symptom (FCPS) system is proposed. FCPS system is composed of outputs of cold/heat pattern through the calculation process of contribution degree to the cold, heat pattern and qi, blood, yin, yang deficiency patterns, based on analysis of 16 mechanisms of disease calculated by diagnostic system of oriental medicine (DSOM) first. And second component is an output of differentiated 8 principle patterns in detail through binding and calculating process with digital informations of pulse, color, form, constitution obtained by computerized measurement system. Putting together above two processes consecutively, cold-heat complex or true/false cold/heat patterns and personalized characters of cold/heat patterns of each patient can be subdivided through a computation method of determining each pattern. In conclusion, 8 principle pattern identification can be performed more accurately using FCPS system than existent self report questionnaire method. These hypothetic proposal is needed to be proven by clinical trial for the future and then the accurate numbers used in each calculational function should be revised properly.

• Journal of Biomedical Engineering Research
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• v.27 no.2
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• pp.59-63
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• 2006

Magnetocardiogram (MCG) topography is a useful diagnostic technique that employs multi-channel magnetocardiograms. Measurement of artifact-free MCG signals is essenctial to obtain MCG topography or map for a diagnosis of human heart. Principal component analysis (PCA) combined with an artificial neural network (ANN) is proposed to remove a pulse-type artifact in the MCG signals. The algorithm is composed of a PCA module which decomposes the obtained signal into its principal components, followed by an ANN module for the classification of the components automatically. In the experiments with volunteer subjects, 97% of the decisions that were made by the ANN were identical to those by the human experts. Using the proposed technique, the MCG topography was successfully obtained without the artifact.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.9 no.1
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• pp.112-124
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• 2005

Background: PWV is determined by dividing the distance by the time taken for the pulses traveling between two measuring sites, used as a marker of arterial stiffness and an important indicator for cardiovascular disease. Methods: A PWV measurement system, which offers a non-invasive, simple method of measurement, and simultaneous recording of six signlas(ECG, PCG and four pulse waves from carotid, femoral, radial and dorsalis pedis arteries) was developed. Seventeen healthy subjects with a mean age of 33 years(22 to 52) without any cardiovascular disease were participated for the experiment. Two observers(A and B) performed two consecutive measurements from the same subject in a random order. For the evaluation of stability and accuracy of the PWV measurement system, reproducibility of PWV from between-observer were also evaluated. Results: PWV $values(Mean{\pm}SD)$ measured by A were $7.07{\pm}1.48m/s$, $8.43{\pm}1.14m/s$ , $8.09{\pm}0.98m/s$ for aorta, arm, and leg, respectively. The values obtained from B were $6.76{\pm}1.00m/s$, $7.97{\pm}0.80m/s$, and $7.97{\pm}0.72m/s$ for aorta, arm, and leg, respectively. Between-observer $differences(mean{\pm}SEM)$ from the aorta, arm and leg were $0.14{\pm}0.15m/s$, $0.18{\pm}0.10m/s$ and $0.07{\pm}0.10m/s$. Reproducibility coefficients(2SD) from the aorta, arm, and leg were 0.62m/s, 0.84m/s and 0.86m/s. Correlation coefficients were significantly higher in aortic PWV, 0.93, compared to the coefficients for arm and leg. Coefficient of variance which reflects the reproducibility of the system ranged from $4.4{\sim}5.8%$ in all regional PWV. , Conclusion: Reproducibility of PWV in the study shows that the developed system has reliable and reproducible characteristics. The PWV measurement system used for the study offers comfortable and simple operation and provides accurate analysis and results with high reproducibility. Results of the PWV measurement system could contribute to various clinical applications in the future.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.6
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• pp.132-140
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• 2019

In this study, a specimen composed of columns, walls, beams, and slabs was fabricated to investigate the estimated reliability using nondestructive test method for the location of structural members of reinforced concrete single layer structures. And for accurate analysis in the comparison process with the existing estimation formula, we try to analyze the reliability through statistical approach by using error rate comparison and Confidence interval estimation. As a result, The average error rate of the core test was 18.8% compared with the result of estimating the compressive strength using the ultrasonic pulse velocity method. The average error rate of the core test results compared with the result of estimating the compressive strength using the rebound hardness method was 20.1%, confirming the field applicability. it is judged that the reliability of the compressive strength estimation can be derived from the wall member to make a quick and efficient structure safety diagnosis using the ultrasonic pulse velocity method. In addition, it is judged that the reliability of the compressive strength estimation can be derived from the beam member to make a quick and efficient structure safety diagnosis using the rebound hardness method.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.5
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• pp.111-116
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• 2022

The causes of motor burnout include overload, phase loss, restraint, interlayer short circuit, winding ground fault, instantaneous overvoltage, and the rotor contacting the stator, leading to insulation breakdown, leading to breakdown or electrical accidents. Therefore, equipment failure causes not only loss due to cost required for equipment maintenance/repair, but also huge economic loss due to productivity decrease due to process stop because the process itself including the motor is stopped. The current level of technology for diagnosing motor failures uses vibration, heat, and power analysis methods, but there is a limit to analyzing the problems only after a considerable amount of time has passed according to the failure. Therefore, in this paper, a device and algorithm for measuring insulation resistance using DC AMP signal was applied to an industrial motor to solve this problem. And by following the insulation resistance state value, we propose a diagnosis of deterioration and failure of the motor that cannot be solved by the existing method.

• Journal of Society of Preventive Korean Medicine
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• v.6 no.1
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• pp.51-95
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• 2002

1. As a point at issue of occidental medicine examination, followings have been indicated, 1) Occidental medical examination is performed by mainly test and instrument and therefore, role of doctors could be excluded and it could be diagnosed only for target disease and 2) in Korea, it could not be conducted in public medical system and therefore improvement effect of public health promotion could not be made due to increase of total medical expenses and infirmity of post management. These points are substantial limit of paradigm resided in occidental medicine and also problem caused by unique characteristics of medical system of Korea. In Korea, result of occidental medical examination show increased health risk from aged thirties and major diagnosed diseases are circulatory disease or chronic disease such as hepatic, hyperlipemic, hypertensional disease and diabetes, etc. Accounting that those chronic disease make a role as major public health risk, it is difficult that medical examination by only occidental medicine make effect on public health promotion. 2. Characteristics of oriental medicine examination could be summarized as diagnosis (information acquisition based on the facts) and demonstration (speculation based on acquired information) and in addition, quadruple diagnosis, as a medical examination method, include test as well as basic examination. Accounting on oriental medical examination, principally it is performed by independent herbalist and therefore, herbalist could acquire systemic result during first medical examination. Based on the theory of inner-outer examination, oriental medical examination has a principle of universe theory, systemic analysis of quadruple diagnosis, demonstration & reasoning. In addition, root of oriental medical examination could be found in pre-disease theory, a principal theory of oriental medicine. Pre-disease service could prove the advantage of oriental medicine in medical examination activities and therefore, it is needed that content of oriental medical examination should be actualized in current medical system. 3. In this study, oriental medical examination program, comprised of pulse-diagnosis, contrast muscular taking and medical consultation of herbalist is progressed communally with occidental medical examination. As pre-examination, questionary was given of general characteristics, health promoting life style, physical constitution and subjective symptom of musculoskeletal system. In addition, post-examination notification was given to subjects about health promoting control, physical constitution regimen and management of musculoskeletal system. During this study program, verification was conducted for input of acquired information and difference of each information after analysis and in addition, performed was analysis of factor influencing health promoting life style and musculoskeletal subjective symptom and evaluation of relationship of physical constitution and health promoting life study. In addition, it was verified of difference between musculoskeletal subjective symptom and result of muscle contrast picture evaluation. 4. Evaluation of oriental medical examination model is divided into 2 categories of oriental medical examination-consultation and result evaluation -post management. Oriental medical examination-consultation demands establishment of examination system, standardization of examination and establishment of examination form and in addition, it should be admitted as enlarged examination assists systemic quadruple diagnosis of herbalist not a key of oriental medical examination. In addition, information acquisition for research purpose should be performed according to the systemic research plan based on the separation of questionary for examination purpose and research purpose. For evaluation of the result, it was concluded that needed are result evaluation meets oriental medical system and post-notification system, informing health management information, based on examination result. 5. Accounting on satisfaction for oriental medical examination model, affirmative reply was much higher (66%) than negative (8.64%). Satisfaction of each area was in order of consultation of herbalist, systemic muscle contrast taking, pulse examination, post-notification and questionary fill-up and dissatisfaction was in order of post-notification, questionary fill-up, consultation of herbalist, systemic muscle contrast taking and pulse measurement. Satisfaction for collaborative examination of occidental and oriental medicine was over 60% and over 75% hope oriental examination would be included in later medical examination program. Based on this result, collaborative examination including occidental and oriental medicine could increase satisfaction of subjects for medical examination program.

• Journal of Pharmacopuncture
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• v.19 no.3
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• pp.197-206
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• 2016

Introduction: This study aims to investigate the effects of acupuncture stimulation on the radial artery's pressure pulse wave, along with various hemodynamic parameters, and to explore the possible underlying mechanism of pulse diagnosis in healthy participants in their twenties. Methods and analysis: This study is a prospective, single-arm, exploratory clinical study. A total of 25 healthy participants, without regard to gender, in their twenties will be recruited by physicians. Written informed consent will be obtained from all participants. The participants will receive acupuncture once at ST36 on both sides. The radial arterial pulse waves will be measured on the left arm of the subjects by using an applicable pulse tonometric device (KIOM-PAS). On the right arm (appearing twice), electrocardiogram (ECG), photoplethysmogram (PPG), respiration and cardiac output (CO) signals, will be measured using a physiological data acquisition system (Biopac module), while the velocity of blood flow, and the diameter and the depth of the blood vessel will be measured using an ultrasonogram machine on the right arm (appearing twice). All measurements will be conducted before, during, and after acupuncture. The primary outcome will be the spectral energy at high frequencies above 10 Hz ($SE_{10-30Hz}$) calculated from the KIOM-PAS device signal. Secondary outcomes will be various variables obtained from the KIOM-PAS device, ECG, PPG, impedance cardiography modules, and an ultrasonogram machine. Discussion: The results of this trial will provide information regarding the physiological and the hemodynamic mechanisms underlying acupuncture stimulation and clinical evidence for the influence of acupuncture on the pressure pulse wave in the radial artery. Ethics and dissemination: This study was approved by the Institutional Review Board (IRB) of Kyung Hee University's Oriental Medical Center, Seoul, Korea (KOMCIRB-150818-HR-030). The study findings will be published in peer-reviewed journals and presented at national and international conferences. Trial registration number: This trial was registered with the Clinical Research Information Service (CRIS) at the Korea National Institute of Health (NIH), Republic of Korea (KCT0001663), which is a registry in the World Health Organization's (WHO's) Registry Network.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2919-2922
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• 2003

In this paper, we present a new methodology to analyze the characteristics of artery by using 4 channels photophethysmography. The proposed parameter is a time difference of pulse transit time (PTT) between pulse waves at finger site and at toe site. As the results of experiments, the change of parameter was found according to ages. The result of regression analysis about relationships between the parameter and ages for n=51, the coefficient of correlation of non-normalized data has -0.79770 in left side and -0.80599 in right side and the coefficient of correlation of normalized data by height has -0.81345 in left side and -0.81605 in right side.