• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 춘계학술대회논문집
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• pp.188-191
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• 1997

In the recent sheet metal forming simulations, it increases to adopt the dynamic explicit method for an effective computation and the elastic-plastic formulation for stress recovery. It is inevitable in the dynamic explicit method that some noises occur and sometimes partly spoil results of simulations. It is severer when complicated contact conditions are included in simulations. An effective method to control these noises is introduction of damping effects. In this paper, the concept of contact damping is introduced in order to suppress noises due to complicated contact conditions. This is checked by analyzing a simple sheet metal forming process(U-bending). From the computational results, it is shown that the contact damping can effectively control the noises due to contacts and develop more reliable internal stress states.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1205-1211
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• 2004

We propose a train position estimation method for automatic train control system. The accurate train position should be continuously feedback to control system for safe and efficient operation of trains in railway. In this paper, we propose the sensor fusion method integrating the tachometer, the transponder, and the doppler sensor for estimation of train position. The external sensors(transponder, doppler sensor) are used to compensate for the error of internal sensor(tachometer). The Kalman filter is also applied to reduce the measurement error of the sensors. Simulation results are then presented to verify the usefulness of the proposed method.

• 대한한방내과학회지
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• 제43권3호
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• pp.375-386
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• 2022

Objectives: The purpose of this study was to summarize current clinical study trends and results regarding transcutaneous electrical nerve stimulation (TENS) treatment for xerostomia. Methods: Studies published from 2017 to 2022 were searched on domestic databases and PubMed. The included studies were analyzed according to the year, language, study design, diagnosis xerostomia method, and TENS treatment method. Results: Nine studies were included. There were three randomized controlled trials (RCTs), three case series, one case report, one case-control study, and one cross-sectional study. Conventional TENS was used in seven studies, and acupuncture-like TENS (ALTENS) was used in one study. The most common TENS attachment site was externally on the skin overlying the parotid gland region, and the setting of TENS was 50 Hz-250 μs the most. In all nine studies, TENS was effective for xerostomia as assessed by salivary flow rate or quality of life questionnaire. Additionally, no persistent adverse events were reported after TENS treatment. Conclusions: TENS treatment for xerostomia can be considered effective and safe, so it can be used in clinical practice.

• 대한핵의학회지
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• 제13권1_2호
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• pp.7-14
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• 1979

Radionuclide cardiac angiography has distinct advantages in safety, patient comfort, cost and ease of performance. This method offers diagnostic accuracy equivalent to that of cardiac catheterization. By this method the qualitative and quantitative diagnosis of the cardiac shunts are available. Also for it is repeatable with ease and more physiologic, it has application in following pre- and post-operative shunt patients. We performed the radionuclide cardiac angiographies in 147 cases of heart diseases and 26 cases of normal group. 1. The detection of left-to-right shunt was possible in 22 of 24 patients, and 2 patients were not diagnosed due to small shunt amount. (Qp/Qs<1.3) In 21 patients of right-to-left shunt, all were diagnosed by radionuclide cardiac angiography. 2. With the pulmonary time-activity curve, $C_2/C_1$ ratio was calculated. In normal control group, a range of $C_2/C_1$ ratios of $21{\sim}38%$ was established with a mean value of $28.6{\pm}4.6%$. In patients with left-to-right shunts determined by catheterization data, the range of $C_2/C_1$ ratio was $33{\sim}90%$, with a mean value of $67.8{\pm}12.2%$. 3. In 8 cases of left-to-right shunt, $Q_p/Q_s$ ratios determined by radionuclide cardiac angiography were compaired with those of cardiac catheterization. The correlation coefficient was 0.907. (P<0.001) 4. Postoperative radionuclide cardiac angiographies were done in 21 cases. 3 of 13 patients with left-to-right shunts were found to have residual shunts. 8 patients with right-to-left shunts were confirmed to have no residual shunt.

• 한국결정성장학회지
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• 제8권4호
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• pp.550-554
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• 1998

Bridgman-Stockbarger법에서 thermal screen의 역할을 하는 새로운 방법을 6inch 형석(CaF2) 단결정성장을 위하여 고안하였다. 본 방법으로 poly-grain으로의 성장과 내부 cavity, 그리고 solid-liquid(SL) interface를 제어할 수 있었다. Graphite pipe와 ceramic warmer를 사용하여 성장한 6inch의 CaF2 결정은 완전한 단결정으로 성장하였다. 이때의 조건은 2mm/hr의 성장속도, 성장구역에서의 $14^{\circ}C$/cm의 온도구배, 그리고 도가니의 conical tip에서 $1324^{\circ}C$의 온도를 나타내었다. 내부 cavity에 의해 발생되는 light scattering 현상은 성장속도를 감소시키거나 융액을 회전함으로써 제어할 수 있었다.

• 대한한의학회지
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• 제18권1호
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• pp.456-469
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• 1997

The cerebral infarction arised from occulsion of cerebral artery has a high mortality rate and fatal sequelae. Sohabhyangwon(蘇合香元) is generally regarded to have a effect of walking up the patient from unconsiousness and promoting the flow of Qj(氣) by warming channel. METHOD The purpose of this study is to find out the effections of Sohabhyangwon(蘇合香元) on regional cerebral blood flow and relative cerebral infarction area in the experimentally induced infartion in rats In this experiment, 12 Spraque-Dawley rats weighting 280-350g were used. Cerebral ischemia induced by intraluminal suture technique of Kozumi's and Zea-Longer's method. $Co_{2},\;O_2$, pH, arterial blood pressure in rats were checked by Blood Gas Analyzer every 30 minutes for 2 hours. And regional cerebral blood flow were checking by hydrogen clearance technique, cerebral infarcted area was megsured by Image Analysis System. RESULTS 1. During the experiment, $CO_{2},\;O_2$, pH, arterial blood pressure in rats had no change in both sample group and control group. 2. Cortical cerebral blood flow decreased at same rate in both sample group and control group after inducing cerebral infarction. 3. On comparison of relative cerebral infarcted area, Sohabhyangwon(蘇合香元) perfused group showed a significant decrease. CONCLUSION According to the result above, Sohabhyangwon has a protection effect on cranial nerve and-has no effect on cerebral blood flow.

• 전자공학회논문지 IE
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• 제46권4호
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• pp.66-72
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• 2009

환경분야에서 산업화와 도시화에 따른 수질오염의 문제를 해결하기 위해 오수처리시설을 제어 및 감시하는 장치들이 개발 되어 왔다. 본 연구에서는 지역에 설치된 오수처리시설의 구동 모터와 주변 환경 상태를 제어하고 감지하기 위하여 시리얼 인터페이스를 갖는 내부 네트워크로 상호 연결한 효율적인 모듈 시스템의 설계방법에 대하여 제안하였다. 본 연구에서 제안된 방법은 급변하는 환경시장에서 요구되는 조건과 환경인자들의 사양에 대하여 보다 적응성 있고 유연한 설계 기법을 제공하리라 기대된다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.855-859
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• 2009

In this paper, we introduce the estimation method by Risk or SIL(Safety Integrity Level) for the criterion of safety assurance and summarize each application method and target. IEC 62278(EN 50126) which is international standard for the specification and verification of the railway system RAMS indicate a criterion of safety assurance. Especially, it recommend the safety verification by continuous verification as the order of requirement establishment, design, manufacture, installation, operation, and maintenance for the equipment not easy to quantify the operation environment. In this paper, we study the SIL requirement allocation method relating to internal new system development and existing system improvement by analysing SIL recommendations which were used to understand SIL for a train control equipment in 1990s in IRSE and theoretically their allocation background. This paper help the safety management of Korea train control system to develope the quantitative management procedure as international level by analyzing the SIL requirement allocation by operation agency and the right SIL verification procedure by manufacture and indicating the example to assure safety because it is necessary for improvement and localization for the Korea train control system having highly dependence on aboard technology.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권4호
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• pp.201-207
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• 2005

This paper has investigated the sensorless vector control method of induction motor based on the stator flux oriented voltage equation and the digital low pass filter (LPF) with compensator of phase/gain. The Proposed vector control method is easy to decide the stator reference voltages and control of motor, since it is based on stator flux vector But this method has sensitive structure to excessive sensor noise and PWM pulsating components of stator currents because the measured stator currents are directly used to compensate the internal resistive voltage drop at the determination of stator reference voltages. To eliminate the noise sensitive of proposed vector drive, this paper propose the digital LPF with compensator of phase/gain base on orthogonal property of stator current vector in stationary $\alpha$, $\beta$ reference frame. The proposed methods have been simulated and implemented on a sensorless vector drive for 750W three-phase induction motor. The simulation and experimental results demonstrate effectiveness of the proposed methods.

• Journal of Electrical Engineering and Technology
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• 제9권5호
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• pp.1614-1622
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• 2014

A novel equivalent flux sliding-mode observer (SMO) is proposed for dual three-phase interior permanent magnet synchronous motor (DT-IPMSM) drive system in this paper. The DT-IPMSM has two sets of Y-connected stator three-phase windings spatially shifted by 30 electrical degrees. In this method, the sensorless drive system employs a flux SMO with soft phase-locked loop method for rotor speed and position estimation, not only are low-pass filter and phase compensation module eliminated, but also estimation accuracy is improved. Meanwhile, to get the regulator parameters of current control, the inner current loop is realized using a decoupling and diagonal internal model control algorithm. Experiment results of 2MW-level DT-IPMSM drives system show that the proposed method has good dynamic and static performances.