• Proceedings of the Korea Concrete Institute Conference
• /
• 2009.05a
• /
• pp.229-230
• /
• 2009

This paper carried out the early age autogenous shrinkage research of large scaled HPC column specimens by embedded Fiber Bragg-Grating (FBG) strain sensor. Temperature compensation for FBG strain sensor by thermocouple was also attempted.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.805-808
• /
• 2008

Due to the fact that bare FBG sensors are very fragile, bare FBG sensor is not properly applied in practical infrastructures as it is not suitable to the rudeness of construction. Therefore packaged FBG sensors are developed for construction application. Since FBG senses strain and temperature simultaneously, temperature compensation for FBG strain sensors is indispensable. In this paper, temperature compensation techniques for steel sleeve packaged FBG sensors are brought forward. And its application on monitoring concrete beam was carried to test the feasibility of the temperature compensation technique. Temperature compensation technique used in this paper is feasible to be extended to structure health monitoring in civil engineering especially in large infrastructures etc.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.514-514
• /
• 2013

플라즈마와 혈액의 상호작용 특성을 파악하기 위해 혈액응고 실험을 하였다. 생체에 적용 가능한 바이오 플라즈마 소스를 개발하여 다양한 조건으로 혈액에 플라즈마를 조사하였다. 혈액 응고의 정량적인 측정 방법으로 혈액의 저항을 측정하였다. 본 실험에 사용된 플라즈마 제트 장치는 의료용 바늘과 유리관, 외부 접지로 이루어져 있다. 플라즈마 제트 장치는 고전압 전극이 유리관 안에 위치하고 접지 전극이 유리관 바깥에 위치한다. 의료용 바늘을 통해 Ar gas를 주입하며, 약 2 kV의 전압을 인가하여 방전시켰다. 자연적으로 혈액을 응고시킨 경우, 칼슘 클로라이드를 첨가하여 응고시킨 경우, Ar gas 및 온풍을 단독적으로 불어넣은 경우, 그리고 플라즈마 제트를 조사한 경우로 나누어 실험을 진행하였다. 두개의 떨어진 전극 사이에 일정량의 혈액을 배치시켜 저항을 측정하여 응고 정도를 파악하였다. 플라즈마 제트를 조사하였을 경우 아무것도 처리하지 않은 자연상태의 혈액보다 혈액이 응고되는 속도가 빠르게 나타났다. Ar gas와 온풍을 단독으로 불어넣어 준 경우와 혈액 표면이 응고되었으나, 약 20초가 지나면 다시 원래 상태의 혈액으로 돌아감을 확인하였다. 플라즈마 제트를 혈액에 조사했을 때는 혈액이 이전의 혈액 상태로 돌아가는 경향이 나타나지 않았다.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.23 no.2
• /
• pp.124-128
• /
• 2012

Background and Objectives : There are many diagnostic modalities to evaluate laryngopharyngeal reflux. However, ideal diagnostic methods have not been established yet. The purpose of this study is to evaluate the effectiveness of Water-Siphon test as a diagnostic test of laryngopharyngeal reflux. Subjects and Methods : From November 2006 to September 2007, we performed esophagography with Water-Siphon test and questionnaire, physical examination for 227 patients with laryngopharyngeal reflux symptoms. The results of Water-Siphon test were classified according to the degree of reflux, the number of reflux, the retention time and analyzed about the relationship with the reflux symptom index (RSI), reflux finding score (RFS). Results : The degree of reflux was related with pseudosulcus, thick endolaryngeal mucus. The number of reflux was related with thick endolaryngeal mucus. A positive predictive value of Water-Siphon test was 82.7% and sensitivity was 91.5%. Conclusion : Water-Siphon test is a reliable diagnostic test for laryngopharyngeal reflux.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.2
• /
• pp.469-472
• /
• 2005

This paper propose about effective speech feature parameter that have robust character in effect of noise in realizing speech recognition system. Established MFCC that is the basic parameter used to ASR(Automatic Speech Recognition) and DCTCs that use DCT in basic parameter. Also, proposed delta-Cepstrum and delta-delta-Cepstrum parameter that reconstruct Cepstrum to have information for variation of speech. And compared recognition performance in using HMM. For dimension reduction of each parameter LDA algorithm apply and compared recognition. Results are presented reduced dimension delta-delta-Cepstrum parameter in using LDA recognition performance that improve more than existent parameter in noise environment of various condition.

• Communications of Mathematical Education
• /
• v.23 no.4
• /
• pp.1023-1041
• /
• 2009

The importance of the mathematical education on the ICT environment has been increased as the educational environment has been changed in 21st century. In Korea, many researches on ICT tools have appeared over the last 10 years. But most of researches are depending on the foreign tools, that was one major obstacle on adapting them in our mathematics curriculum. But we found the new open source tool which is called Sage-Math can be in effective solution to resolve those problems. Now we produce what we have done in linear algebra with this Sage-Math and mobile modules.

• Transactions of the Korean hydrogen and new energy society
• /
• v.34 no.2
• /
• pp.141-148
• /
• 2023

The thermodynamic performance of the electrochemical hydrogen compressor was analyzed to perform a comparative analysis with the performance of the mechanical compressor. The performance was analyzed through the applied current and the measured voltage value. The test results showed that the efficiency of the electrochemical hydrogen compressor was high in the low current density range. In addition, it was confirmed that the amount of increasing compress work of the electrochemical hydrogen compressor is smaller than that of the mechanical compressor. Therefore, it is expected to have higher efficiency than mechanical compression when compressed with a sufficiently high-pressure range.

• Transactions of the Korean hydrogen and new energy society
• /
• v.34 no.2
• /
• pp.149-154
• /
• 2023

In the Fourth Industrial Revolution, hydrogen energy is in the spotlight. There is a difficulty in commercialization due to the lack of hydrogen infrastructure. Therefore, a lot of hydrogen should be imported and a method using ammonia is the most useful. In this study, using the mixed gas of hydrogen and nitrogen generated when ammonia is decomposed, the hydrogen separation performance is to be tested. Hydrogen was separated using an electrochemical hydrogen compressor based on a fuel cell and the experiment was conducted by changing the ratio of hydrogen and nitrogen. In addition, the performance was also compared by the difference both the pressure and the membrane.

• Advances in pediatric surgery
• /
• v.12 no.1
• /
• pp.53-69
• /
• 2006

This is a survey on congenital posterolateral diaphragmatic hernia, conducted by the Korean Association of Pediatric Surgeons(KAPS). A registration form for each patient during the 5-year-period between 1998 and 2002 and a questionaire were sent to each member. Twenty-ninemembers in 22 institutions returned completed forms. The average number of patients per surgeon was 1.4 cases a year. The male to female ratio was 1.64: 1, and annual incidencewas 1/14,522 live births. In this review, factors influencing survival in congenital posterolateral diaphragmatic hernia were age at admission, birth weight, time of antenatal diagnosis, birth place, Apgar score, onset time of symptoms and signs, preoperative cardiopulmonary resuscitation, associated anomalies of themusculoskeletal system, central nervous system, or chromosomes, preoperative stabilization, levels of preoperative $FiO_2$, pH, and $AaDO_2$, perioperative complications, bilaterality of defect, size of the defect, and presence or absence of hernia sac.

• Journal of Soil and Groundwater Environment
• /
• v.20 no.1
• /
• pp.41-55
• /
• 2015

Monitoring of $CO_2$ release through the ground surface is essential to confirm the safety of carbon storage projects. We conducted a feasibility study of the multi-channel surface-soil $CO_2$-concentration monitoring (SCM) system as a soil $CO_2$ monitoring tool with a small scale injection test. The background concentrations showed the distinct diurnal variation. The negative relation of $CO_2$ with temperature and the low $CO_2$ concentrations during the day imply that surface-soil $CO_2$ depends on photosynthesis and respiration. After 4.2 kg of $CO_2$ injection (1 m depth for 29 minutes), surface-soil $CO_2$ concentrations increased in the all five chambers, which were located less than 2.8 m of distance from each other. The $CO_2$ concentrations seem to be recovered to the background around 4 hours after the injection ended. To determine the leakage, the data from Chamber 2 and 5 with low increase rates were used for statistical analyses. Coefficient of variation for 30 minutes ($CV_{30min}$.) is efficient to determine a leakage signal, with reflecting the fast change in $CO_2$ concentrations. Consequently, SCM and $CV_{30min}$ could be applied for an efficient monitoring tool to detect $CO_2$ release through the ground surface. Also, this study provides ideas for establishing action steps after leakage detection.