• 한국정밀공학회지
• /
• 제29권1호
• /
• pp.96-102
• /
• 2012

The current establishment of car engineering plastic piping polyethylene (PE) tube used as bonding state or part of the health or safety of fusion is very important. A part of these fusion methods to determine the soundness of the short-term trials and long-term tests can be largely classified. Typical tests included short-term strength, tensile strength, impact strength, compressive strength, resiliency and compression. Polyethylene (PE) pipes installed in the domestic terms of overall penetration rate of 45% has been used. However, polyethylene (PE) pipes have reliability problems, and these occurs mostly in part by defective welding. Therefore, the test is necessary for safety. Non-destructive methods (ultrasonic testing) are difficult to be used. Therefore, Polyethylene (PE) pipe are used. Fusion of thses materilas is necessary in these field however, its technical, and basic research has not been studied well. In this research, short-term strength of welding parts, its tensile strength, hardness, fatigue, and microstructure have been analyzed to find the optimum process conditions to improve mechanical properties.

• 한국생산제조학회지
• /
• 제20권5호
• /
• pp.564-569
• /
• 2011

The current establishment of city gas piping polyethylene (PE) tube used as bonding state or part of the health or safety of fusion is very important. A part of these fusion methods to determine the soundness of the short-term trials and long-term tests can be largely classified. Typical tests include short-term strength, tensile strength, impact strength, compressive strength, resiliency and compression. Polyethylene (PE) pipes installed in the domestic terms of overall penetration rate of 45% has been used. However, polyethylene (PE) pipes have reliability problems, and these occurs mostly in part by defective welding. Therefore, the test is necessary for safety. Non-destructive methods (ultrasonic testing) are difficult to be used. Therefore, Polypropylene copolymer (PP-C), polypropylene homopolymer (PP-H), and polyethylene (PE) pipe are used. Fusion of these materials is necessary in these field however, its technical, and basic research has not been studied well. In this research, short-term strength of welding parts, its tensile strength, hardness, fatigue, and microstructure have been analyzed to find the optimum process conditions to improve mechanical properties.

• Journal of Animal Science and Technology
• /
• 제63권4호
• /
• pp.884-891
• /
• 2021

The study aimed to evaluate pork loin quality after short-term (ten-day) storage in a supercooling refrigerator. Pork loin samples were stored for 10 days in a traditional refrigerator (control) and a commercially available supercooling refrigerator (SC). Pork quality measurements included meat pH, meat color, water holding capacity (drip loss and cooking loss), tenderness (hardness), and a sensory evaluation. Temperature changes of 0.45 ± 0.2℃ and 0.02 ± 0.25℃ occurred in the control and the SC, respectively, during 10 days of storage. The temperature in the SC chamber did not remain below freezing point, failing to meet expectations. Regarding the pork quality measurements, only the drip losses in the control and the SC were significantly different (4.45% vs. 2.59%, p < 0.01) after 10 days of storage. There were no significant differences between the two types of refrigerator in terms of the other measurements. Additionally, the overall acceptability of the pork loin did not vary significantly between the control and the SC when the sensory evaluation was performed. Therefore, a commercial SC could prove beneficial in terms of water holding capacity during the short-term storage of meat. Further research should be performed to evaluate quality changes that occur during long-term storage of meat in SC s and evaluate a wide range of meat, such as beef and chicken.

• 대한한의학회지
• /
• 제28권2호통권70호
• /
• pp.66-79
• /
• 2007

Objectives : To explore the type and frequency of short term reactions, de Qi associated with acupuncture treatment and to determine the incidence of adverse events following acupuncture in Korea. Subjects and methods : This study is a retrospective and cross-sectional survey of patient reports. 1095 subjects, 585 of out-patients of the Oriental Medicine of Stroke & Neurological Disorders Center, East-West NEO Medical Center of Kyunghee University and 510 of out-patients of the Department of Cardiovascular & Neurologic Diseases (Stoke Center), Hospital of Oriental Medicine, Kyunghee Medical Center, from June through November of 2006, who had acupuncture, gave informed consent and completed one survey form. On this form, patients were asked to report short term acupuncture reactions, de Qi, patient satisfaction measurement (using VAS), and adverse events relating to acupuncture treatment. The acupuncturists of this study are Korean Medicine Doctors (KMD) who had worked as practitioners for 3-30 years or more. Results : The average age of the 1095 subjects was 58 years old. Positive short term acupuncture reactions after treatment were reported by 878 (80.2%), negative short term acupuncture reactions by 75 (6.8%) and no reactions were reported by 142 (13.0%). The most common positive short term acupuncture reactions were feeling 'relaxed', 472 (43.1%), followed by feeling 'less pain' 90 (8.2%), 'energized' 16 ( 1.5%), 'tingling' 16 (1.5%), 'heat feeling or Cold feeling' 10 (0.9%), and others 274 (25.0%), respectively. Negative short term acupuncture reactions were feeling 'pain' 37 (3.4%), tiredness 24 (2.2%), dizziness 9 (0.8%), and others 5 (0.2%), respectively. Traditionally described needling sensations of de Qi refer to a patient's response to distention, pulling, soreness, heaviness, numbness. 39.7% of subjects reported de Qi during needling, experiencing 'distention' 333 (30.4%), 'soreness' 52 (4.7%), 'pulling' 22 (2.0%), 'heaviness' 18 (1.6%), and 'numbness' 10 (0.9%) respectively. Positive short term acupuncture reactions and de Qi rate were the highest in the less than 40 years group (83/96 86.5%, 50/96 52.1%). No acupuncture reactions were highly seen in the over 70 years old group (31/187, 16.6%). Patient satisfaction level using VAS was a comparatively high $72.9{\pm}19.9$. Adverse events were only bleeding in 92 (8.4%) of the total subjects. High sensitive acupoints were 95 points as GV26 (54 times), LI4 (54 times), ST36 (53 times), GB20 (37 times), HT8(34 times), LV3 (29 times), SI3 (29 times), and LI11 (27 times) in order. Main impressions were stroke patients 430 (16.9%), headache 185 (16.9%), hypertension 97 (8.9%), and dizziness 85 (7.8%). Conclusions : Although 8 different Korean Medicine Doctors participated in this research, we obtained similar results from each. There were no significantly different results between the two hospitals. Short term acupuncture reactions and de Qi were most related to age. Except for bleeding there were no adverse events relating to acupuncture treatment in this study. We consider acupuncture treatment as very safe depending on practitioners. Positive short term acupuncture reactions after treatment were 12 times higher than negative short term acupuncture reactions. Subjects were comparatively satisfied with acupuncture treatment.

• The Journal of Asian Finance, Economics and Business
• /
• 제6권2호
• /
• pp.15-24
• /
• 2019

This study analyzes the effect of the capital structure of Korean manufacturing firms on default risk based on Moody's KMV option pricing model where the probability of default is obtained by measuring the distance to default as a covariant in logit model developed by Merton (1974). Based on the panel data of manufacturing firms, this study achieves its primary objective, using a fixed effect regression model and examines the effect of a firm's capital structure on default risk amongst publicly listed firms on Korea exchange during 2005-2016. Empirical results obtained suggest that the rise in short-term debt to assets leads to increase the risk of default whereas the increase in long-term debt to assets leads to decrease the default risk. The benefits of short-term debt financing over a short-term period fade out in the presence of information asymmetry. However, long-term debt financing overcomes the information asymmetry and enjoys the paybacks of tax advantage associated with long-term debt. Additionally, size, tangibility and interest coverage ratio are also the important determinants of default risk. Findings support the trade-off theory of capital structure and recommend the optimal use of long-term debt in a firm's capital structure.

• 한국환경과학회지
• /
• 제28권10호
• /
• pp.863-872
• /
• 2019

Using the Standard Precipitation Index (SPI), this study analyzed the drought characteristics of ten weather stations in Gyeongbuk, South Korea, that precipitation data over a period of 30 years. For the number of months that had a SPI of -1.0 or less, the drought occurrence index was calculated and a maximum shortage months, resilience and vulnerability in each weather station were analyzed. According to the analysis, in terms of vulnerability, the weather stations with acute short-term drought were Andong, Bonghwa, Moongyeong, and Gumi. The weather stations with acute medium-term drought were Daegu and Uljin. Finally the weather stations with acute long-term drought were Pohang, Youngdeok, and Youngju. In terms of severe drought frequency, the stations with relatively high frequency of mid-term droughts were Andong, Bonghwa, Daegu, Uiseong, Uljin, and Youngju. Gumi station had high frequency of short-term droughts. Pohang station had severe short-term ad long-term droughts. Youngdeok had severe droughts during all the terms. Based on the analysis results, it is inferred that the size of the drought should be evaluated depending on how serious vulnerability, resilience, and drought index are. Through proper evaluation of drought, it is possible to take systematic measures for the duration of the drought.

• Nuclear Engineering and Technology
• /
• 제55권5호
• /
• pp.1630-1643
• /
• 2023

The correct situation awareness (SA) of operators is important for managing nuclear power plants (NPPs), particularly in accident-related situations. Among the three levels of SA suggested by Ensley, Level 3 SA (i.e., projection of the future status of the situation) is challenging because of the complexity of NPPs as well as the uncertainty of accidents. Hence, several prediction methods using artificial intelligence techniques have been proposed to assist operators in accident prediction. However, these methods only predict short-term plant status (e.g., the status after a few minutes) and do not provide information regarding the uncertainty associated with the prediction. This paper proposes an algorithm that can predict the multivariate and long-term behavior of plant parameters for 2 h with 120 steps and provide the uncertainty of the prediction. The algorithm applies bidirectional long short-term memory and an attention mechanism, which enable the algorithm to predict the precise long-term trends of the parameters with high prediction accuracy. A conditional variational autoencoder was used to provide uncertainty information about the network prediction. The algorithm was trained, optimized, and validated using a compact nuclear simulator for a Westinghouse 900 MWe NPP.

• 한국콘텐츠학회논문지
• /
• 제10권9호
• /
• pp.201-211
• /
• 2010

본 연구의 목적은 정보 디자인 유형 중에서 상대적으로 "노출 시간이 짧지만 정보 전달력이 강한 정보" 즉, STM 정보(Short-term Memorable Information)” 에 대한 사용자의 인지력을 높이기 위한 방법을 모색하는 것이다. 연구를 통해 STM 정보의 디자인 속성을 고찰하고 거시적 관점에서 디자인적 표현 방법을 다음과 같이 제안하였다. STM 정보는 기능변수의 조작, 방법, 사건, 사용 예라는 네 가지 시각화 속성을 기준으로 시각적 재현 측면에서 '이해도(Understandable)', '접근성(Accessibility)' 속성이 충족되어야 한다. 또한 사용자 조작 측면에서는 '무오류(Errorless)', '적정성(Timeliness)' 속성이 충족되어야 한다. 각 측면에서의 거시적 표현 방법으로써, 시각적 재현 측면에서 "속성이론", "인식모형", "정보 주도성(Proactivity)의 최대화", "잉여 정보의 최소화", "이중부호의 사용"을 제안했으며, 사용자 조작측면에서 "맥락효과", 일차적 독특성을 중심으로 한 "기억부호화", "정보 주사(Scanning)"의 두 가지 방법을 제안했다. 사용자 설문 인터뷰를 통해서 앞서 제안한 8가지 표현 방법의 효율성에 관한 확증 및 STM 정보에 대한 사용자 인지패턴을 발견하였다. 본 연구에서의 주요 발견점을 토대로 향후에는 노출시간별 효과적인 정보 표현 및 그에 따른 응용 방법에 관한 연구가 진행될 필요가 있다.

• 한국산학기술학회논문지
• /
• 제11권3호
• /
• pp.1085-1094
• /
• 2010

최근 경제 불황으로 인한 고용 축소와 비자발적인 퇴직이 늘어가는 반면에 창업은 증가하고 있다. 그러나 충분한 사전 정보와 창업 지식이 결여된 준비 없는 창업은 실패를 가져올 수밖에 없다. 따라서 성공적인 창업을 위해서는 효과적인 창업 교육이 필수적이다. 본 연구는 지방자치단체가 실시하는 단기 창업교육프로그램 수강자의 학습참여동기, 창업의지, 교육 만족도, 자기 유능감이 창업교육성과에 미치는 영향을 고찰하고, 교육 성과에 영향을 미치는 가설을 검증한다. 본 연구는 요인분석을 사용하여 교육성과에 미치는 요인을 탐색하고, 가설의 검증을 위하여 구조 방정식 모형을 이용하여 가설을 검증한다. 본 연구 결과는 단기간 수행되는 창업교육프로그램의 효과성을 증진하기 위한 정책 수립, 교육프로그램 구성, 수강자 선발 등 정책 수립에 활용할 수 있다.

• 노동경제논집
• /
• 제35권3호
• /
• pp.51-81
• /
• 2012

본 연구는 저소득층의 4년제 대학진학을 제약하는 두 가지 요인, 즉 등록금 납부여력 부족과 불우한 성장환경의 누적적 영향에 따른 학업능력 부족 중 무엇의 영향이 더 큰지 살펴보았다. 희귀분석 결과, 중학교 시기의 학업성취와 몇몇 가정배경 변수들은 유의한 반면, 이들 변인 통제 시 대학진학 시기의 가구소득은 4년제 대학 진학에 거의 영향을 주지 못했다. 또한 Carneiro and Heckman(2003)이 미국 고등교육 격차 원인규명을 위해 수행한 분석을 한국 상황에 적용해 본 결과, 학업능력 및 가정배경의 격차로 4년제대에 진학하지 못하는 비율이 등록금 납부가 어려워 진학하지 못하는 비율을 크게 능가했다. 이는 등록금 인하와 같은 단기적 제약요인의 완화만으로는 대입격차문제 해결이 힘듦을 시사한다.