• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2587-2589
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• 1999

In this paper, we propose a new control scheme for a PWM inverter using digital control. Digital control has various advantages in comparison with conventional analogue control. It can achieve high frequency switching of inverter and can be little influenced for temperature variations and aging of devices. This digitally-controlled PWM inverter is implemented using a Digital Signal Processor(DSPTMS320F240). The simulation results are given to verify the DSP based PWM inverter design and implementation.

• Archives of Reconstructive Microsurgery
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• 제17권1호
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• pp.55-59
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• 2008

Varix of the digit is generally defined as an enlarged, tortuous palmar digital vein with or without thrombus within it. It usually presents as a firm, blue mass on the volar aspect of the finger. Mechanical compression or chronic trauma to veins on the volar surface of a digit appears central to the pathogenesis of this lesion. Aging phlebectasia has also been considered as a cause of this lesion in the elderly. A tourniquet test may be useful in demonstrating the presence of a digital varix, but it is confirmed by postoperative microscopic examination. Excision of a symptomatic lesion has proven to be curative. We report two cases of symptomatic digital varix which developed in the fourth finger with a review of literatures.

• 디지털콘텐츠학회 논문지
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• 제6권4호
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• pp.255-260
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• 2005

디지털카메라와 같은 디지털 입력기구들의 발달로 아날로그 데이터들의 디지털 이미지 전환이 간편해지고 높은 픽셀과 해상도의 입력이 가능해지고 있다. 이에 따라 노화나 손상으로 인한 사잔 필름, 문서 둥 심한 노이즈로 판독하기 어려운 이미지의 형태나 글자를 디지털 이미지로서 복원 및 판독 할 수 있는 가능성이 높아지고 그 방법 요구되고 있다. 본 논문에서는 노이즈로 손상된 이미지의 형태의 복원을 위하여 이미지의 글자나 형태들의 윤곽을 형성하는 규칙적인 픽셀의 결과값을 추출하기 위한 이미지들의 합성과 색상함수의 매핑을 통한 디지털이미지 프로세싱을 방법을 제안한다.

• International journal of advanced smart convergence
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• 제8권3호
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• pp.87-94
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• 2019

IoT-based services are being released in accordance with the aging population and the demand for well-being pursuit needs. In addition to medical device companies, companies with ideas ranging from global ICT companies to startup companies are accelerating their market entry. The areas where these services are most commonly applied are health/medical, life/safety, city/energy, automotive and transportation. Furthermore, by expanding IoT technology convergence into the area of life care services, it contributes greatly to the development of service models in the public sector. It also provides an important opportunity for IoT-related companies to open up new markets. By addressing the problems of life care services that are still insufficient. We are providing opportunities to pursue the common interests of both users and workers and improve the quality of life. In order to establish IoT-based digital life care services, it is necessary to develop convergence technologies using cloud computing systems, big data analytics, medical information, and smart healthcare infrastructure.

• 디지털산업정보학회논문지
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• 제19권3호
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• pp.25-38
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• 2023

Instrumentation and control systems measure and control various variables of nuclear facilities to operate nuclear power plants safely. A diverse protection system, a representative instrumentation and control system, generates a reactor trip and turbine trip signal by high pressure in a pressurizer and containment to satisfy the design requirements 10CFR50.62. Also, it generates an auxiliary feedwater actuation signal by low water levels in steam generators. Cybersecurity has become more critical as digital technology is gradually applied to solve problems such as performance degradation due to aging of analog equipment, increased maintenance costs, and product discontinuation. This paper analyzed possible cybersecurity threat scenarios in the diverse protection system using attack trees. Based on the analyzed cybersecurity threat scenario, we calculated the probability of attack occurrence and confirmed the cybersecurity risk in connection with the asset value.

• 한국정보통신학회논문지
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• 제26권11호
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• pp.1755-1758
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• 2022

One of the most negative social changes of the last decade is population aging which leads to 19 times more patients with Mild Cognitive Disorder(MCI). It is well established that MCI is the most important state that can prevent dementia with early diagnosis and intervention. However, the social security system for patients with dementia is not working properly due to the coronavirus pandemic and the limited human power. This article proposes a form of workbench and design principles for dementia training programs of extended reality devices. and the findings in this study provide a guide for considering the cognitive and physical and social functions of patients.

• 한국전자통신학회논문지
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• 제18권6호
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• pp.1371-1378
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• 2023

키오스크는 무인 서비스와 결제 시스템을 제공하는 중요한 도구로 인기를 얻고 있으며, 서비스 업계에서 빠르게 증가하고 있다. 그러나 디지털 기술과 터치스크린에 익숙하지 않은 노인들에게는 키오스크 사용이 어려울 수 있다. 이에 따라, 이 연구는 메타버스 기술을 활용하여 노인들의 디지털 기술 및 키오스크 서비스 접근성을 향상시키는 교육 프로그램을 개발한다. 본 연구는 노인들의 디지털 기술 및 키오스크 접근을 놀이로써 익힐 수 있도록 교육 시스템으로 만들었다.

• 비파괴검사학회지
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• 제29권6호
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• pp.591-602
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• 2009

The Compton backscatter technique has been applied to lap-joint in aircraft structure in order to determine mass loss due to exfoliative corrosion of the aluminum alloy sheet skin. The mass loss of each layer has been estimated from Compton backscatter A-scan including the aluminum sheet, the corrosion layer, and the sealant. A Compton backscattering imaging system has been also developed to obtain a cross-sectional profile of corroded lap-splices of aging aircraft using a specially designed slit-type camera. The camera is to focus on a small scattering volume inside the material from which the backscattered photons are collected by a collimated scintillator detector for interpretation of material characteristics. The cross section of the layered structure is scanned by moving the scattering volume through the thickness direction of the specimen. The theoretical model of the Compton scattering based on Boltzmann transport theory is presented for quantitative characterization of exfoliative corrosion through deconvolution procedure using a nonlinear least-square error minimization method. It produces practical information such as location and width of planar corrosion in layered structures of aircraft, which generally cannot be detected by conventional NDE techniques such as the ultrasonic method.

• 보존과학연구
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• 통권26호
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• pp.77-101
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• 2005

In ancient times, many kinds of difference inorganic and organic pigment were used as colorants for making objects. This study has proved the damage regions on the aging conditions of the silk dyeing traditional pigment. so whiteness, tensile strength and digital-microscope were measured to examine the state of silk dyeing traditional pigments pretreated under each aging condition. From the result examining the state, all the silk dyeing traditional pigments were best condition at low temperature(-20/RT)and normal condition and damaged at high temperature($60^{\circ}C$) and 2ppm $SO_2$condition and UV condition. As a result of X-ray diffraction analysis of crystalline structure for the silk dyeing traditional pigments, most of specimens have nearly changed crystalline structure despite specimens had each other different conditions and times. Especially, specimens which was passing of 4-8 months have not changed in its crystalline structure. But some specimens like a Unghwang and Seokcheong have a little changed in its intensity in the XRD peak. Consequently, If we want to find out alteration of crystalline structure for the silk dyeing traditional pigments using scientific method according to change of environmental conditions, we must guarantee of equal state and strengthen of environmental conditions in specimen. Additionally, the term of experiment need to belong, and specimens which was experimented and analyzed must be same.

• 한국전문물리치료학회지
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• 제28권3호
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• pp.177-185
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• 2021

Background: Muscle undergoes change continuously with aging. Sarcopenia, in which muscle mass decrease with aging, is associated with various diseases, the risk of falling, and the deterioration of quality of life. Obesity and sarcopenia also have a synergy effect on the disease of the older adults. Objects: This study examined the risk factors for sarcopenia, sarcopenic obesity, and sarcopenia without obesity and developed prediction models. Methods: This machine-learning study used the 2008-2011 Korea National Health and Nutrition Examination Surveys in the analysis. After data curation, 5,563 older participants were selected, of whom 1,169 had sarcopenia, 538 had sarcopenic obesity, and 631 had sarcopenia without obesity; the remaining 4,394 were normal. Decision tree and random forest models were used to identify risk factors. Results: The risk factors for sarcopenia chosen by both methods were body mass index (BMI) and duration of moderate physical activity; those for sarcopenic obesity were sex, BMI, and duration of moderate physical activity; and those for sarcopenia without obesity were BMI and sex. The areas under the receiver operating characteristic curves of all prediction models exceeded 0.75. BMI could predict sarcopenia-related disease. Conclusion: Risk factors for sarcopenia-related diseases should be identified and programs for sarcopenia-related disease prevention should be developed. Data-mining research using population data should be conducted to enhance the effectiveness of early treatment for people with sarcopenia-related diseases through predictive models.