• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 춘계종합학술대회
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• pp.347-350
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• 2007

본 연구는 무선 센서네트워크를 활용하여 환자 또는 고령자를 위한 ECG, 활동량 모니터링 시스템을 설계 및 구현하였다. 심전도 변화는 사람의 활동, 뛰거나 걷기 등의 움직임에 따라 조금씩 변화한다. 그래서 종종 자세, 행동에 따른 ECG변화의 기록은 중요시되며 이를 위해 매일 활동하는 환자의 활동 모니터링 시스템이 필요하다. ECG와 활동량 데이터는 자동 알림기능을 지원하는 시스템에 저장되고 긴급 상황 발생 시 보다 빠르게 초기 활동을 할 수 있게 한다. 몸에서 계측된 ECG 데이터와 활동량 데이터는 무선 센서네트워크를 통해 베이스테이션과 연결된 서버에 전송되며 서버에서 비정상적 상황을 판별시 발생 의사의 PDA 또는 서버에 데이터를 전송한다.

• 약학회지
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• 제48권6호
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• pp.352-357
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• 2004

Atrial myocytes have two functionally separate groups of ryanodine receptors (RyRs): those at the periphery colocalized with L-type $Ca^{2+}$channels (DHPRS) and those a t the cell interior not associated with DHPRs. $Ca^{2+}$ current ($I_{ca}$) directly gates peripheral RyRs on action potential and the subsequent peripheral $Ca^{2+}$ release propagates into the center of atrial myocytes. The mechanisms that regulate the $Ca^{2+}$+ propagation wave remain Poorly understood. Using 2-D confocal$Ca^{2+}$ imaging, we examined the role of inositol 1,4,5-trisphosphate receptor (IP $_3R$) and mitochondria on ($I_{ca}$)- gated local $Ca^{2+}$ signaling in rat atrial myocytes. Blockade of IP $_3R$ by xestospongin C (XeC) partially suppressed the magnitudes of I ca-gated central and peripheral $Ca^{2+}$ releases with no effect on $I_{ca}$. Mitochondrial staining revealed that mitochondria were aligned with ${\thickapprox}2-{\mu}m$ separations in the entire cytoplasm of ventricular and atrial myocytes. Membrane depolarization induced rapid mitochondrial $Ca^{2+}$ rise and decay in the cell periphery with slower rise in the center, suggesting that mitochondria may immediately uptake cytosolic $Ca^{2+}$, released from the peripheral SR on depolarization, and re-release the $Ca^{2+}$ into the cytosol to activate neighboring central RyRs. Our data suggest that the activation of IP $_3R$ and mitochondrial $Ca^{2+}$ handing on action potential may serve as a cofactor for the $Ca^{2+}$ propagation from the DHPR-coupled RyRs to the DHPR-uncoupled RyRs with large gaps between them.

• 대한조선학회지
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• 제22권3호
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• pp.9-18
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• 1985

The numerical calculation for solving boundary-value problem related to potential flows with a free surface is carried out by application of the localized finite element method. Only forced motion of 2-D body in infinitely deep fluid is considered, although this schemes is equally applicable to any first order time-harmonic problems of similar nature. The infinite domain of the fluid is separated into the inner flow field and the outer flow field with common inter-surface boundary. The finite element method is applied to obtain the solution in the inner flow field and the Green functions are utilized to represent the solution in the outer flow field. At the inter-surface boundary, the continuity of the value of potential and the normal derivative of the potential(i.e. matching condition) is conserved. The present method has better computational efficiency than the previous LFEM and the integral equation method of Frank. This enhanced computational efficiency is presumably due to the fact that the present method gives a symmetric coefficient matrix and requires less computational time in calculating the influence coefficient matrix of Green function than the integral equation method. And the irregular frequency desen't exist because the uniqueness of the solution is assured by the such that the exact free surface condition is satisfied on the boundary of the localized finite element region(i.e. inner region). As an example of the above method, the hydrodynamic forces for the circular cylinder and the rectangular cylinders are calculated. In the computed results, the small number of singularity distribution segments($3{\sim}6$) give good result relative to Ursell's and Vugts'.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.561-569
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• 2002

Laser has been called a "Quantum Machine" because of its mechanism of generation since the development on July 7,1960.by T.H.Maiman. We can now use this machine as a tool for manufacturing in industries. At present, 45kW CO2 laser, 10kW Nd:YAG laser, 6kW LD pumped YAG laser and 4kW direct diode laser facilities are available for welding a heavy steel plate of 40mm in thickness and for cutting metals at high speed of 140m/min. Laser Materials Processing is no longer a scientific curiosity but a modern tool in industries. Lasers in manufacturing sector are currently used in welding, cutting, drilling, cladding, marking, cleaning, micro-machining and forming. Recently, high power laser diode, 10kW LD pumped YAG laser, 700W fiber laser and excimer laser have been developed in the industrialized countries. As a result of large numbers of research and developments, the modem laser materials processing has been realized and used in all kinds of industries now. In the present paper, metallurgical studies on laser materials processing such as porosity formation, hot cracking and the joint performances of steels and aluminum alloys and dissimilar joint are discussed after the introduction of laser facilities and laser applications in industries such as automotive industry, electronics industry, and steel making industry. The wave towards the use of laser materials processing and its penetration into many industries has started in many countries now. Especially, development of high power/quality diode laser will be accelerate the introduction of this magnificent tool, because of the high efficiency of about 50%, long life time and compact.

• 한국지반공학회논문집
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• 제28권5호
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• pp.77-84
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• 2012

Diatom 성분이 함유된 자연 퇴적토층의 공학적 특성은 대상층의 변형 및 강도의 특이한 특성 때문에 다수의 연구자에 의해 수 십년간 연구되어 왔다. 원반형 혹는 원통형 모양을 한 diatom의 존재는 재료의 낮은 압축성, 높은 투수성, 높은 전단강도 특성을 나타내게 하며, 이러한 특이한 차이점들은 큰 내부입자 간극과 모난 입자의 결합력으로 diatom의 특성을 나타낸다. 이러한 현상은 흙의 공학적 특성을 변화시켜서 지반개량 재료로써 diatom을 이용할 수 있음을 의미한다. 본 논문은 diatom 개량토의 공학적 특성을 연구하기 위해 diatom-kaolin 혼합토의 공학적 특성을 통상적인 지반공학 실험 및 탄성파를 이용한 미소변형 실험, 전자기파를 이용한 전기저항 측정실험 등을 통하여 평가하였다. 실험 결과에 따르면, diatom 함유량에 따라 흙의 공학적 개선이 이루어진 것을 확인할 수 있었으며, 높은 응력에서 diatom 입자의 결합이 파괴되어 일부 공학적 특성이 저감되는 것을 확인 할 수 있었다.

• 지역사회간호학회지
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• 제27권4호
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• pp.358-369
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• 2016

Purpose: This study was to identify health-related quality of life of Korean young adults and elderly with multimorbidity and to examine factors influencing their health-related quality of life. Methods: Health-related quality of life was measured by the Korean version of the EQ-5D. Using a descriptive study, the study incorporated a secondary analysis of the Korean version of the EQ-5D data from the 8th wave of the Korea Health Panel Survey in 2013. Selected demographic data and the Korean version of the EQ-5D were analyzed using ${\chi}^2$-test, t-test, ANOVA and multiple regression analysis. Results: Education, drinking, type of health insurance, and number of chronic disease significantly affected the health-related quality of life in the young adults with multimorbidity. Educational level, occupational type, drinking, physical activity, number of chronic disease, unmet healthcare need and the type of multimorbidity significantly affected the health-related quality of life in the elderly with multimorbidity. Conclusion: The factors influencing health-related quality of life were different for young adults versus elderly with multimorbidity. Therefore, there is a need for age-specific health care programs that may improve health-related quality of life of adults with multimorbidity.

• 한국항해항만학회지
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• 제28권3호
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• pp.207-211
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• 2004

LMTT(Linear Motor-based Transfer Technology)는 항만 자동화를 위한 컨테이너 터미널용 수평 이송 장치이며, rail과 shuttle car(mover)에 부착된 stator module로 구성된 PMLSM(Permanent Magnetic Linear Synchronous Motor)에 의해 구동된다. 본 논문은 inner beam과 outer beam의 높이비가 LMTT용 shuttle car의 frame 강도 및 강성에 미치는 영향을 살펴보았다. 설계변수는 inner beam의 단면형상 및 높이비로 설정하였으며, 유한요소해석을 통하여 설계변수가 frame의 강도 및 강성에 미치는 영향을 살펴보았다.

• 한국전자파학회논문지
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• 제16권2호
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• pp.228-234
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• 2005

준 마이크로파 대역용 전자파 노이즈의 흡수체로서 자성 복합 시트를 개발하였다. Fe-Si-Al 자성 분말을 attrition mill을 이용해 편상화한 후 이것을 polymer와 혼합 분산시켜 전자파의 입사 방향에 수직한 방향으로 배향된 자성 복합 시트를 제조하였다. Attrition milling 시간이 긴 편상 분말일수록 제조된 자성 복합체의 유전율은 증가하나 투자율은 다소 감소하는 경향을 보인다. 또한 오랜 시간 milling한 편상 분말일수록 임피던스 정합 주파수는 저주파 쪽으로 이동하나 정합 주파수에서의 전자파 흡수율은 감소한다. 이러한 결과들로부터 복합 자성체의 유전율과 투자율의 주파수 특성을 제어하여 1.4 GHz에서 -8.2 dB의 반사 손실 특성을 갖는 두께 1.0 mm의 노이즈 흡수 시트를 개발하였다.

• 천문학회지
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• 제38권4호
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• pp.471-478
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• 2005

Spectroscopic data obtained by the Infrared Interferometer Spectrometer (IRIS) aboard Voyager 1 and 2 have been re-visited. Using the spectroscopic data and footprints of the IRIS aperture on the planet, we constructed images of the stratosphere of Jupiter at the emission bands of hydrocarbons including $CH_4,\;C_2H_6,\;C_2H_2,\;C_3H_4,\;C_6H_6$, and $C_2H_4$. Thermal emission from the hydrocarbons on Jupiter originates from a broad region of the stratosphere extending from 1 to 10 millibars. We averaged the data using a bin of 20 degrees of longitude and latitudes in order to increase signal-to-noise ratios. The resultant images show interesting wave structure in Jupiter's stratosphere. Fourier transform analyses of these images yield wavenumbers 5 - 7 at mid-Northern and mid-Southern latitudes, and these results are different from those resulted from previous ground-based observations and recent Cassini CIRS, suggesting temporal variations on the stratospheric infrared pattern. The comparisons of the Voyager 1 and 2 spectra also show evidence of temporal intensity variations not only on the infrared hydrocarbon polar brightenings of hydrocarbon emissions but also on the stratospheric infrared structure in the temperate regions of Jupiter over the 4 month period between the two Voyager encounters. Short running title: Stratospheric Images of Jupiter derived from Voyager IRIS Spectra.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2007년도 추계학술발표회
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• pp.51-55
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• 2007

As for satellite programs, the multipurpose satellite 1(KOMPSAT-1) was successfully launched on Dec. 21, 1999 and operated for three years. It is still properly operated even though its life cycle was ended. The development of KOMPSAT-2 (Korea Multipurpose Satellite-2) is near completion and the development of KOMPSAT-3, KOMPSAT-5 and COMS (Communication, Ocean, Meterological Satellite) are proceeding swiftly. In KORDI(Korea Ocean Research and Development Institute), the KOSC (Korea Ocean Satellite Center) construction project is being prepared for acquisition, processing and distribution of sensor data via L-band from GOCI(Geostationary Ocean Color Imager) instrument which is loaded on COMS(Communication, Ocean and Meteorological Satellite); it will be launched in 2000. Ansan(the headquarter of KORDD has been selected for the location of KOSC between 5 proposed sites, because it has the best condition to receive radio wave. The data acquisition system is classified antenna and RF. Antenna is designed to be ${\emptyset}$ 9m cassegrain antenna which has 19.35 $G/T(dB/^{\circ}K)$ at 1.67GHz, RF module, is divided into LNA(Low noise amplifier) and down converter, those are designed to send only horizontal polarization to modem The existing building is re-designed and classified for the KOSC operation concept; computing room, board of electricity, data processing room, operation room Hardware and network facilities have been designed to adapt for efficiency of each functions. The distribution system which is one of the most important systems will be constructed mainly on the internet, and it is also being considered constructing outer data distribution system as a web hosting service for to offering received data to user under an hour.