• The Journal of the Acoustical Society of Korea
• /
• v.41 no.2
• /
• pp.242-253
• /
• 2022

When the source waveform is unknown, the Green's function can be estimated by Ray-based Blind Deconvolution (RBD) based on the simple array signal processing. In previous papers, RBD was successfully demonstrated using simulation and experiments in shallow water environment. In this paper, we investigate the applicability of RBD for a long-range communication (e.g., 30 km, 60 km, and 90 km) in a deep water environment (1,000 m ~), using experimental data conducted in the east of Pohang, South Korea, in October 2018. Data results are presented to demonstrate Green's function estimation of a communication signal (2.2 kHz ~ 2.9 kHz) using a 16-element, 42-m long vertical array. The results show that the Green's function estimated from RBD is comparable to that of matched filter result. Additional communication performance at a maximum range of 90 km will be also presented.

• Journal of Chest Surgery
• /
• v.56 no.2
• /
• pp.99-107
• /
• 2023

Background: The neutrophil-to-lymphocyte ratio (NLR) has been suggested as a novel predictive marker of cardiovascular disease. However, its prognostic role in patients under-going coronary artery bypass grafting (CABG) is unclear. This study aimed to determine the association between the preoperative NLR and early mortality in patients undergoing CABG. Methods: Cardiac surgery was performed in 2,504 patients at Seoul St. Mary's Hospital from January 2010 to December 2021. This study retrospectively reviewed 920 patients who underwent isolated CABG, excluding those for whom the preoperative NLR was unavailable. The primary endpoints were the 30- and 90-day mortality after isolated CABG. Risk factor analysis was performed using logistic regression analysis. Based on the optimal cut-off value of preoperative NLR on the receiver operating characteristic curve, high and low NLR groups were compared. Results: The 30- and 90-day mortality rates were 3.8% (n=35) and 7.0% (n=64), respectively. In the multivariable analysis, preoperative NLR was significantly associated with 30-day mortality (odds ratio [OR], 1.28; 95% confidence interval [CI], 1.17-1.39; p<0.001) and 90-day mortality (OR, 1.17; 95% CI, 1.07-1.28; p<0.001). The optimal cut-off value of the preoperative NLR was 3.4. Compared to the low NLR group (<3.4), the high NLR group (≥3.4) showed higher 30- and 90-day mortality rates (1.4% vs. 12.1%, p<0.001; 2.8% vs. 21.3%, p<0.001, respectively). Conclusion: Preoperative NLR was strongly associated with early mortality after isolated CABG, especially in patients with a high preoperative NLR (≥3.4). Further studies with larger cohorts are necessary to validate these results.

• Journal of Oriental Neuropsychiatry
• /
• v.19 no.3
• /
• pp.35-44
• /
• 2008

Objective: There are many meditation methods used in clinical field. But the effect of meditation may be different to people's mind, and meditation itself. Now we investigate this subject with two different meditation methods which has been analyzed by heart rate variability. Method: We tried to check people's heart rate who educated meditation, before educated and during the meditation. The meditation was educated differently for each group. One is the auto genes traning, and the other is the imaginary meditation by thinking about eating and smelling favorite fruits. All of them are used to oriental psychiatry clinic patients. And we simultaneously conduct people's emotional state by SCL-90-R. Result: The result in Autogene traning group has significant difference in total power and HRV-index score between before and during the training but in imaginary meditation group has no significance: Autogene traning group has a significance in low frequency score and has increased tendency with increasing tendency of Heart rate index and Total power. Through the SCL-90-R score, the higher depression t-score, the anxiety t-score, and the hostility score is, the HRV scores such as total power, low frequency, and HRV-index much increase. and so on. Conclusion: We can guess that the Autogenes training has more significant effect than the imaginary meditation. And we can also guess that as the emotional problem is getting more severe, the effect of meditation would be much better. And we finally suggest that we should make a standard guideline of imaginary meditation, cause the imaginary meditation has so many variation.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 2001.11a
• /
• pp.90-90
• /
• 2001

CCAP법을 이용하였을 때 SAM에서 taurine의 뇌 분포용적은 정상생쥐보다 85 % 감소하였다. 그리고 10, 15, 30초 동안의 뇌 분포용적은 linear regression을 나타내었다. 또한 intravenous injection technique의 결과, SAMP8에서의 sucrose space가 정상생쥐에 비하여 감소하였음을 알 수 있었다. 반면에 choline의 경우는 정상생쥐보다 SAMP8의 뇌분포용적이 73% 증가하였다.

• Proceedings of the Korean Society of Embryo Transfer Conference
• /
• 2004.10a
• /
• pp.90-90
• /
• 2004

• Proceedings of the Korean Vacuum Society Conference
• /
• 2004.02a
• /
• pp.90-90
• /
• 2004

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1998.08a
• /
• pp.90.2-90
• /
• 1998

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.2
• /
• pp.265-270
• /
• 2013

Strength design for a lightweight bicycle frame made of carbon/epoxy composite laminates was studied using Tsai-Wu's failure criterion. For the design of bicycle frames, reducing the weight of the frame is of great importance. Furthermore, the frame should satisfy the required strength under specific loading cases. In accordance with the European EN 14764 standard for bicycle frames, three loading cases-pedaling, vertical, and level loadings-were investigated in this study. Because of the anisotropic characteristics of composite materials, it is important to decide the appropriate stacking sequence and the number of layers to be used in the composite bicycle frame. From finite element analysis results, the most suitable stacking sequence of the fiber orientation and the number of layers were determined. The stacking sequences of $[0]_{8n}$, $[90]_{8n}$, $[0/90]_{2ns}$, $[{\pm}45]_{2ns}$, $[0/{\pm}45/90]_{ns}$ (n = 1, 2, 3, 4) were used in the analysis. The results indicated that the $[0/{\pm}45/90]_{3s}$ lay-up model was suitable for a composite bicycle frame. Furthermore, the weakest point and layer were investigated.

• Korean Journal of Environmental Agriculture
• /
• v.18 no.4
• /
• pp.332-338
• /
• 1999

To treat livestock wastewater effectively by electrochemical method using a stainless steel electrode or au aluminum electrode, the effects of voltage, distance of electrodes and PACS(Poly Aluminum Chloride Silicate) dosage on removals of pollutants in batch experiment for investigation the optimum treatment conditions of livestock wastewater were investigated. The results were summarized as follows ; On the effect of voltage, temperature and pH in electrochemical reactor were increased with increase in voltage but EC was a reverse in both electrodes. Removals of COD and T-N were increased with increase in voltage in both electrodes. SS removal was greater than 90% regardless of voltage without doing electrochemical reaction over 15min at 20V or 12min at 30V in both electrodes. T-P removal was over 90% regardless of voltage in both electrodes. On the effect of distance between two electrodes, removals of COD, T-N and T-P were increased with closeness in distance between two electrodes, and SS removal was greeter than 90% regardless of distance between two electrodes in both electrodes. On the effect of PACS dosage, removals of COD, T-N and T-P were increased with increased in PACS dosage up to 200㎎/l in both electrodes. SS removal was greater than 90% regardless of PACS dosage in both electrodes.

• Clinical and Experimental Pediatrics
• /
• v.50 no.6
• /
• pp.543-548
• /
• 2007

Purpose : The anthropometric data of newborns published by Lubchenco et al in the 1960's have been most commonly used in Korea as a standard of newborn growth. We hypothesized that Lubchenco's data have limitations for Korean premature infants born in the 2000's. We analyzed and compared the data of birth weight, length, and head circumference. Methods : The medical records of 1,159 premature infants of 26 to 35 weeks of gestational age born at Il-Sin Christian Hospital of Busan from January 2,000 to August 2,006 were reviewed. The anthropometric data from total 1,010 premature infants were analyzed after excluding the data from infants whose gestational age were estimated by other than ultrasonogram, and infants with major congenital anomalies or chromosomal anomaly, born from foreign parent, and extreme outliers. Results : In the birth weights by gestational age, our 90 percentile values were lower than Lubchenco's 90 percentile values for all gestational age studied, particularly for less than 30 weeks the 90 percentile curve was drawn at the area as that of Lubchenco' 75 percentile. And our 10 percentile values were higher than Lubchenco's 10 percentile values for all gestational age studied. In the birth length and head circumference by gestational age, our 90 percentile values were lower than Lubchenco's 90 percentile values for all gestational age studied, and the 90 percentile curve was drawn at the area as that of Lubchenco's 75 percentile. And our 10 percentile values were higher than Lubchenco's 10 percentile values for all gestational age studied. Conclusion : It is unreasonable to apply Lubchenco's data published before 4th decades to present Korean premature infants and have a risk to underestimate intrauterine growth retardation or small for gestational age and large for gestational age. Considering for the possibility of increasing the mortality and morbidity of premature infants due to delayed diagnosis and treatment by these underestimating, our anthropometric data of premature infant is expected to contribute to lower the mortality and morbidity of premature infants.