• Title/Summary/Keyword: USC

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Variation of probability of sonar detection by internal waves in the South Western Sea of Jeju Island (제주 서남부해역에서 내부파에 의한 소나 탐지확률 변화)

  • An, Sangkyum;Park, Jungyong;Choo, Youngmin;Seong, Woojae
    • The Journal of the Acoustical Society of Korea
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    • v.37 no.1
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    • pp.31-38
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    • 2018
  • Based on the measured data in the south western sea of Jeju Island during the SAVEX15(Shallow Water Acoustic Variability EXperiment 2015), the effect of internal waves on the PPD (Predictive Probability of Detection) of a sonar system was analyzed. The southern west sea of Jeju Island has complex flows due to internal waves and USC (Underwater Sound Channel). In this paper, sonar performance is predicted by probabilistic approach. The LFM (Linear Frequency Modulation) and MLS (Maximum Length Sequence) signals of 11 kHz - 31 kHz band of SAVEX15 data were processed to calculate the TL (Transmission Loss) and NL (Noise Level) at a distance of approximately 2.8 km from the source and the receiver. The PDF (Probability Density Function) of TL and NL is convoluted to obtain the PDF of the SE (Signal Excess) and the PPD according to the depth of the source and receiver is calculated. Analysis of the changes in the PPD over time when there are internal waves such as soliton packet and internal tide has confirmed that the PPD value is affected by different aspects.

The Characterization of Controlled Low Strength Material (CLSM) Using High CaO Fly Ash without Chemical Alkaline Activator (고칼슘 플라이애쉬를 이용한 알칼리 활성화제 무첨가 저강도 유동화 채움재 특성 평가)

  • Lim, Sanghyeong;Choo, Hyunwook;Lee, Woojin;Lee, Changho
    • Journal of the Korean GEO-environmental Society
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    • v.17 no.12
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    • pp.17-26
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    • 2016
  • The experimental investigation aims at developing controlled low strength materials (CLSM) using a self-cementitious fly ash (FA) as a binder and a bottom ash (BA) as a aggregate. The fly ash and bottom ash used in this study were obtained from a circulating fluidized bed combustion boiler (CFBC) which produces relatively high CaO containing fly ash. To find the optimum mixing condition satisfying flow consistency and unconfined compression strength (UCS), the CLSM specimens were prepared under various mixing conditions, including two types of aggregate and different weight fractions between fly ash and aggregate. Additionally, the prepared specimens were evaluated using a scanning electron microscope (SEM) and X-ray diffraction (XRD). The results of this study demonstrate that the water content satisfying flow consistency ranges from 42% to 85% and the flowability is improved with increasing the fraction of aggregate in whole mixture. The USC ranges from 0.3 MPa to 1.9 MPa. The results of UCS increases with increasing the fraction of aggregate in FA-sand mixtures, but decreases with increasing the fraction of aggregate in FA-BA mixtures. SEM images and XRD patterns reveal that the occurrence of both geopolymerization and hydration. The results of this study demonstrate that CFBC fly ash could be used as an alternative binder of CLSM mixtures.

The Effect of Car-Free Pedestrian Street Policy on Urban Vibrancy Using Synthetic Control Method (통제집단합성법을 활용한 차 없는 거리 정책의 도시 활력 증진 효과 분석)

  • Ha, Jungwon;Ha, Jaehyun;Lee, Sugie
    • Journal of the Korean Regional Science Association
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    • v.38 no.2
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    • pp.59-72
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    • 2022
  • In line with increasing interest of climate change and pedestrian rights, the city of Seoul has been implementing car-free pedestrian street policies. The government and the private sector agreed to introduce carfree streets, expecting to increase the urban vibrancy and attract customers in the streets. However, studies that empirically analyze the effects of the policy are insufficient, and there are no studies that reevaluate the car-free pedestrian street policy after the COVID-19 outbreak. Therefore, this study evaluates the car-free pedestrian street policy at the commercial street, the Jongno 52-gil, using the synthetic control method. As a result of the analysis, it was found that the car-free pedestrian street policy was valid for enhancing urban vibrancy. Also, it was found that proper time interval is required to assess the policy since the peak increase of policy was observed in 3 months after the policy implementation. However, less than a year, the increase of the de facto population density on the Jongno 52-gil was revealed to be insignificant. In addition, the Jongno 52-gil was more vulnerable in the decrease of the de facto population density in the COVID-19 period than the synthetic control region. The results of this study suggest that long-term population inflow measures and flexible counterplan to contagious diseases are necessary in the car-free pedestrian street policy.

The Effect of Early IASP and Reperfusion Therapy in Patient of Post MI Cardiogenic Shock (Post MI Cardiogenic Shock 환자에서 조기 IABP 및 Reperfusion Therapy의 효과)

  • Lee, Jong-Suk;Kim, Min-Kyeung;Kim, Woong;Kim, Hyung-Jun;Bae, Jun-Ho;Park, Jong-Sean;Sin, Dong-Gu;Kim, Young-Jo;Shim, Bong-Sup
    • Journal of Yeungnam Medical Science
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    • v.17 no.1
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    • pp.31-38
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    • 2000
  • Background: We sought to examine the use and outcomes of early intraaortic balloon counterpulsation(IABP) combined with early reperfusion therapy in patients presenting cardiogenic shock complicated acute myocardial infarction. The usc of IABP in patients with cardiogenic shock is widely accepted. However there is not ample information on the use of this technique in patients with cardiogenic shock who arc treated with reperfusion therapy in Korea. Materials and Methods: Twenty-eight patients presented with cardiogenic shock were classified into two groups: the early IABP group (insertion within 12 hours after AMI onset time) and the late IABP group (insertion after 12 hours). We compared In-hospital mortality between the two groups (early IABP group vs late IABP group). Results: Two groups showed no significant difference in clinical feature and coronary angiographic results. Among total 28 patients, 7 patients were treated with thrombolytic therapy and 21 patients with PTCA. Insertion site bleeding, fever, thrombocytopenia were reported as some of the complications of IABP insertion. In-hospital mortalities in the early IABP group and late IABP group were 4 patients(25%) and 8 patients(66%), respectively(p<0.05). Early IABP insertion and early PTCA showed lower hospital mortality rates. There was significant difference in the time to PTCA after AMI onset between the two groups(p<0.05). Conclusion: IABP appears to be useful in patients presenting cardiogenic shock unresponsive medical therapy. Early IABP insertion and early reperfusion therapy may reduce in-hospital mortality rates of post-MI cardiogenic shock patients.

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Clinical Study of Acute and Chronic Pain by the Application of Magnetic Resonance Analyser $I_{TM}$ (자기공명분석기를 이용한 통증관리)

  • Park, Wook;Jin, Hee-Cheol;Cho, Myun-Hyun;Yoon, Suk-Jun;Lee, Jin-Seung;Lee, Jeong-Seok;Choi, Surk-Hwan;Kim, Sung-Yell
    • The Korean Journal of Pain
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    • v.6 no.2
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    • pp.192-198
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    • 1993
  • In 1984, a magnetic resonance spectrometer(magnetic resonance analyser, MRA $I_{TM}$) was developed by Sigrid Lipsett and Ronald J. Weinstock in the USA, Biomedical applications of the spectrometer have been examined by Dr. Hoang Van Duc(pathologist, USC), and Nakamura, et al(Japan). From their theoretical views, the biophysical functions of this machine are to analyse and synthesize a healthy tissue and organ resonance pattern, and to detect and correct an abnormal tissue and organ resonance pattern. All of the above functions are based on Quantum physics. The healthy tissue and organ resonance patterns are predetermined as standard magnetic resonance patterns by digitizing values based on peak resonance emissions(response levels or high pitched echo-sounds amplified via human body). In clinical practice, a counter or neutralizing resonance pattern calculated by the spectrometer can correct a phase-shifted resonance pattern(response levels or low pitched echo-sounds) of a diseased tissue and organ. By administering the counter resonance pattern into the site of pain and trigger point, it is possible to readjust the phase-shifted resonance pattern and then to alleviate pain through regulation of the neurotransmitter function of the nervous system. For assessing clinical effectiveness of pain relief with MRA $I_{TM}$ this study was designed to estimate pain intensity by the patient's subjective verbal rating scale(VRS such as graded to no pain, mild, moderate and severe) before application of it, to evaluate an amount of pain relief as applied the spectrometer by the patients subjective pain relief scale(visual analogue scale, VAS, 0~100%), and then to observe a continuation of pain relief following its application for managing acute and chronic pain in the 102 patients during an 8 months period beginning March, 1993. An application time of the spectrometer ranged from 15 to 30 minutes daily in each patient at or near the site of pain and trigger point when the patient wanted to be treated. The subjects consisted of 54 males and 48 females, with the age distribution between 23~40 years in 29 cases, 41~60 years in 48 cases and 61~76 years in 25 cases respectively(Table 1). The kinds of diagnosis and the main site of pain, the duration of pain before the application, and the frequency of it's application were recorded on the Table 2, 3 and 4. A distinction between acute and chronic pain was defined according to both of the pain intervals lasting within and over 3 months. The results of application of the spectrometer were noted as follows; In 51 cases of acute pain before the application, the pain intensities were rated mild in 10 cases, moderate in 15 cases and severe in 26 cases. The amounts of pain relief were noted as between 30~50% in 9 cases, 51~70% in 13 cases and 71~95% in 29 cases. The continuation of pain relief appeared between 6~24 hours in two cases, 2~5 days in 10 cases, 6~14 days in 4 cases, 15 days in one case, and completely relived of pain in 34 cases(Table 5~7). In 51 cases of chronic pain before the application, the pain intensities were rated mild in 12 cases, moderate in l8 cases and severe in 21 cases. The amounts of pain relief were noted as between 0~50% in 10 cases, 51~70% in 27 cases and 71~90% in 14 cases. The continuation of pain relief appeared to have no effect in two cases. The level of effective duration was between 6~12 hours in two cases, 2~5 days in 11 cases, 6~14 days in 14 cases, 15~60 days in 9 cases and in 13 cases the patient was completely relieved of pain(Table 5~7). There were no complications in the patients except a mild reddening and tingling sensation of skin while applying the spectrometer. Total amounts of pain relief in all of the subjects were accounted as poor and fair in 19(18.6%) cases, good in 40(39.2%) cases and excellent in 43(42.2%) cases. The clinical effectiveness of MRA $I_{TM}$ showed variable distributions from no improvements to complete relief of pain by the patient's assessment. In conclusion, we suggest that MRA $I_{TM}$ may be successful in immediate and continued pain relief but still requires several treatments for continued relief and may be gradually effective in pain relief while being applied repeatedly.

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