• Title/Summary/Keyword: Technique

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A New Random PWM Technique for Conducted-EMI Mitigation on Cuk Converter

  • Krishnakumar, C.;Muhilan, P.;Sathiskumar, M.;Sakthivel, M.
    • Journal of Electrical Engineering and Technology
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    • v.10 no.3
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    • pp.916-924
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    • 2015
  • Electromagnetic Interference (EMI) is a system to system or environment to system phenomenon. The literature survey proved that the Randomized Pulse Width Modulation (RPWM) technique is a promising technique to reduce EMI. A new Constant Trailing Edge, Randomized Pulse Width Modulation (CTERPWM) technique is proposed in this paper. The effect of the proposed RPWM technique for mitigation of conducted-EMI on Cuk converter operating in Continuous Conduction Mode (CCM) is simulated and tested. In this paper, the analytical expressions for the Power Spectral Density (PSD) are derived for the proposed RPWM technique and are validated by experimental measurements. The effectiveness of the proposed RPWM technique on the mitigation of conducted-EMI is verified comparing simulation and experimental results and it is identified that both the results are almost similar with allowable experimental deviations. The comparative investigation proves that the proposed RPWM technique can mitigate and spread the dominant peaks of conducted-EMI over the complete spectrum for the Cuk converter. Based on the investigation the CTERPWM technique is recommended for adoption.

An Iterative Technique for Real-Time Tracking of Power System Harmonics

  • Sidhu, T.S.;Zadeh, M.R.D.;Pooranalingam, P.J.;Oh, Yong-Taek
    • Journal of Electrical Engineering and Technology
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    • v.6 no.3
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    • pp.319-327
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    • 2011
  • An iterative technique based on orthogonal filters and frequency tracking is proposed to estimate harmonic components in power systems. The technique uses frequency interpolation to estimate fundamental frequency and harmonics when the nominal frequency of the signal is a non-integer value. Due to the number of computations involved during the generation of filter coefficients, an offline computation is suggested. Beneficial features of the proposed technique include fixed sampling rate and fixed data window size. The performance of the proposed technique is examined by simulating different power system operating conditions and evaluating the data from these simulations. A technique based on Fast Fourier Transform is also used to estimate the harmonic components for all the simulated signals. These estimates are compared with those obtained from the proposed technique. Results show that the proposed technique can converge to the accurate fundamental frequency and therefore, provide accurate harmonic components even when the fundamental frequency is not equal to the nominal frequency.

Evaluation of the Usefulness for Air Gap Technique in Digital Magnification Mammography (디지털 유방확대촬영술에서 Air gap technique의 유용성 평가)

  • Kim, Mi-Young
    • Journal of radiological science and technology
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    • v.37 no.2
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    • pp.101-107
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    • 2014
  • The purpose of this study was investigated optimal exposure condition in digital magnification mammography to decrease radiation dose and increase image quality of the examinee. Auto mode, the average glandular dose is higher than the manual mode. Average glandular dose and image quality were many differences on between grid and air gap technique in auto mode. However, Average glandular dose and signal-to-noise ratio were not different on between grid and air gap technique in manual mode. The signal-to-noise ratio was increased when using the air-gap technique in both mode. According to result, air gap technique may reduce average glandular dose and increase signal-to-noise ratio in digital magnification mammography.

The Study for Application of the Hot Medicinal Compress Technique of the Donguibogam ("동의보감(東醫寶鑑)"에 기재된 위법(熨法)의 활용에 대한 조사)

  • Kwon, O-Sang;Baek, Seung-Min;Kim, Sul-Gi;Choi, Sun-Mi
    • Korean Journal of Acupuncture
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    • v.28 no.4
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    • pp.137-145
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    • 2011
  • Objectives : This research dealt with the content of the hot medicinal compress technique in Donguibogam in order to develope the hot medicinal compress technique as a new therapy technique. Methods : In this research, we searched for the hot medicinal compress treatment in Donguibogam. Results : The hot medicinal compress technique mainly cures the diseases on the body surface and it can be applied to digestive troubles and gynecologic diseases. The hot medicinal compress technique is operated mainly at wound around the affected parts and it is applied to the constitutional symptom at the abdominal region. In the hot medicinal compress technique was used much more with medication, and the herbs used in the treatment consists of hot tastes and the warm characteristics. In the hot medicinal compress method with direct heating the herbs was mainly used. Conclusions : The hot medicinal compress technique is considered as treatment which can be utilized easily and it can be used an easy and useful self-treatment.

Comparative Study on the Radiation Techniques for the Problem of Floating Body Motion with Forward Speed (전진 속도를 가지는 부유체 운동 문제에 대한 방사기법 비교 연구)

  • Oh, Seunghoon
    • Journal of the Society of Naval Architects of Korea
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    • v.56 no.5
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    • pp.396-409
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    • 2019
  • In this paper, a comparative study on the radiation techniques for the motion analysis of the three dimensional floating structure with the forward speed was carried out. The Sommerfeld radiation condition, the damping technique, and the point shift technique were used for the comparative study. Radiated wave patterns and hydrodynamic coefficients of the heave motion of floating structure with the forward speed were compared and analyzed. The characteristics and limitations of each radiation technique were analyzed through the calculation results. To overcome the limitations of conventional radiation techniques, the hybrid radiation technique combining the Sommerfeld radiation condition with the damping technique was proposed. It is confirmed that the proposed method, the Hybrid radiation technique, improves the limitation of the speed range and the dissipation of the wave of the conventional radiation technique. The motion analysis code of the three dimensional floating structure with the forward speed based on the Rankine source method with hybrid radiation technique was developed. In order to validate the developed code, hydrodynamic analyses were carried and compared with published experiments.

A STUDY ON THE SEALING ABILITY OF McSpadden TECHNIQUE (McSpadden Technique의 근관폐쇄효과에 대한 실험적 연구)

  • Lee, Sang-Tag;Lee, Jung-Sik
    • Restorative Dentistry and Endodontics
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    • v.10 no.1
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    • pp.127-134
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    • 1984
  • This study was conducted to evaluate the sealing ability of McSpadden technique compared with lateral condensation and Engine reamer technique, and according to the degree of canal enlargement and the use and nonuse of sealer. Seventy single-rooted teeth were divided into 14 groups and each tooth was enlarged and obturated according to the purpose of this study. Obturated teeth were infiltrated by Indian ink and decalcified and cleared. The apical sealing ability was evaluated by measuring the degree of ink penetration into the canal. The results were as follows: 1. All the teeth filled by lateral condensation using gutta-percha cone and sealer proved better in canal sealing ability than McSpadden technique and Engine reamer technique, showing less ink penetration. 2. In the McSpadden technique, there was less ink penetration detected in using the sealer than not. 3. In all of the experimental methods, the difference of the degree of ink penetration according the degree of canal enlargement could not be accepted. 4. There was no significant difference in ink penetration degree between Engine reamer technique using sealer and McSpadden technique without sealer.

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A SCANNING ELECTRON MICROSCOPIC STUDY ON THE LABIAL MARGINAL FIT OF METAL CERAMIC CROWNS MADE BY DIFFERENT TECHNIQUES (도재전장주조관의 제작방법에 따른 순측 치경부 변연 적합도에 관한 주사전자현미경적 연구)

  • Yoon, Il-Joong;Chang, Wan-Shik;Yang, Jae-Ho;Lee, Sun-Hyung
    • The Journal of Korean Academy of Prosthodontics
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    • v.24 no.1
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    • pp.151-164
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    • 1986
  • The purpose of this study was to evaluate the marginal fit of metal ceramic crowns made by different techniques. The techniques were metal butt margin technique, platinum foil technique, shoulder powder techniques and wax technique. The latter three techniques were for the fabrication of collarless metal ceramic crowns. Ten crowns were made of each techniques, and marginal fit was evaluated using scanning electron microscope under X200 magnification. The results were as follows. 1. The marginal fit in the descending order were wax technique shoulder powder technique, platinum foil technique and metal butt margin, before cementation, and wax technique, shoulder powder technique, metal butt margin, and platinum foil technique, after cementation. 2. The fit of collarless metal ceramic crowns was comparable to metal ceramic crowns with metal butt margins. 3. There were no statistically significant differences between marginal fit of metal ceramic crowns made by different techniques.

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Current Status of Intraosseous Infusion Technique Use at Emergency Departments in Korea (국내 응급실에서의 골수강내 주입법 사용 현황)

  • Choi, Sang Cheon;Park, Hyun Soo;Kim, Jae Woo
    • Journal of Trauma and Injury
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    • v.20 no.1
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    • pp.6-11
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    • 2007
  • Purpose: Gaining vascular access is difficult and time-consuming in critically ill children, so nowdays, in many countries, intraosseous vascular access is frequently used for rapid vascular access in critically ill children. Its pharmacokinetics is close to that of the peripheral intravenous route, but its infusion flow rate is faster. The purpose of this study was to determine how widely the intraosseous infusion technique was being used in Korean emergency departments. Methods: We telephoned forty-two (42) randomly selected university-affiliated hospitals. We asked physicians if they use the intraosseous infusion technique. Responders were emergency and pediatric residents and emergency faculty. If they responded that they were not using the intraosseous infusion technique, we asked the reason. Also, we asked about their experiences with the intraosseous infusion technique. Results: Forty-two (42) hospitals were enrolled in this study. No hospital used the intraosseous infusion technique on a regular basis. However, 8 hospitals used the intraosseous infusion technique occasionally. None of the responders had experience with the intraosseous infusion technique. Conclusion: The intraosseous infusion technique is currently underrepresented at emergency departments in Korea.

Enhancing Venous Anastomosis Visualization in Murine Kidney Transplants: The Two Stay Suture Technique

  • Jong-Min Kim
    • Journal of Veterinary Clinics
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    • v.40 no.6
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    • pp.423-428
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    • 2023
  • The mouse kidney transplantation model serves as an invaluable tool for exploring various aspects of the transplant process, including acute rejection, cellular and humoral rejection, ischemia-reperfusion injury, and the evaluation of novel therapeutic strategies. However, conducting venous anastomosis in this model poses a significant challenge due to the thin and pliable characteristics of the renal vein, which often obstruct clear visualization of the resected vein's edge. This study proposes the adoption of a two stay suture technique to enhance the visualization of the renal vein's edge, thereby facilitating efficient and successful venous anastomosis. A total of 22 mice served as kidney donors in this study. The conventional anchoring suture technique was employed for venous anastomosis in 11 of these mice, while the remaining 11 underwent the two stay suture technique. The anastomosis duration and completion rates were then compared between these two groups. The conventional anchoring suture technique yielded an average anastomosis time of 29 minutes and a completion rate of 64%. In contrast, the two stay suture technique demonstrated a substantial improvement, with an average anastomosis time of 14 minutes and a completion rate of 100%. The two stay suture technique offers a promising solution to enhance visualization during venous anastomosis in murine kidney transplantation. This technique may particularly benefit novices by enabling them to perform venous anastomosis more easily, swiftly, and successfully.

Comparision of Inclusion TechnicRue with Open Technique in Patients with Bentall Procedures (Bentall수술에서 inclusion technique 과 open technique의 비교)

  • 김정택;문준호
    • Journal of Chest Surgery
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    • v.30 no.5
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    • pp.506-511
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    • 1997
  • To understand the clinical results of aortic root replacement with either inclusion or open technique, we analysed 53 patients who underwent replacement of the aortic root with composite graft between October,1980, and May, 1995. Annuloaortic ectasia was the most common indication for operation(29 patients), follwed by aortic dissection(22 patients). Among 53 patients, 19(35%) had Marfan syndrome. Three patients died during hospitalization (Mortality: 5.5%). The follow up was possible in 48 patients(Follow-up rate; 94%,mean duration;37 months). The actuarial survival rate at 24 months was 95% in open technique group, and 87% in inclusion technique group. Late complications developed in 10 patients. Dissecting aneurysm in the remaining aorta was noted in 3 patients with inclu ion 1,schnique, and a pseudoaneurysm from coronary artery anastomosis site developed in a patient with inclusion technique. In conclusion, there was no statistical differences in survival for 24 months between inclusion technique and open technique group. But late problems in the remaining aorta or death from unknown cause occurred with moderate frequency : careful follow-up after aortic root replacement thought to be important for long term survival.

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