• 자원ㆍ환경경제연구
• /
• 제28권4호
• /
• pp.583-615
• /
• 2019

본 논문은 1990~2016년 기간의 우리나라 온실가스 배출량과 경제성장 간 비동조화 수준에 대한 장단기 분석을 실시하였다. 환경쿠즈네츠곡선 존재 여부에 초점을 맞추어 수행된 기존 연구와 달리 본 연구는 온실가스와 경제성장 간 관계(온실가스 배출의 소득탄력성)의 단기 변동성에 초점을 맞추어 분석을 수행하였다. 분석결과 장기적으로는 온실가스 - 경제성장 - 화석연료 간 견고한 인과관계가 존재하여 비동조화로 평가하기에 어려운 것으로 나타난 반면, 단기적으로는 상대적 비동조화가 뚜렷하게 확인되었다. 이를 통해 현재 국가 온실가스 배출전망 및 감축목표 상에 배출 소득탄력성의 단기 변동성을 고려하지 못하는 한계점을 제기하였으며, 국가 단위 내 화석연료소비, 특히 발전부문의 화석연료 의존도가 온실가스 배출 소득탄성치의 단기 변동성을 낮추는 주요 요인임을 제시하였다.

• 한국환경과학회지
• /
• 제28권11호
• /
• pp.1033-1040
• /
• 2019

The National Environmental Specimen Bank (NESB) has set up a plan to develop reference materials in the facility for assuring analytical quality and validating analytical methods for its monitoring samples. Some of the crucial characteristics that reference materials must consist of are homogeneity and stability of both intra and inter-bottles. In this study, we examined the homogeneity and stability of cryogenically-milled muscle samples, from Common Carp (Cyprinus carpio) for total mercury. Homogeneity was tested using ANOVA analysis and regression analysis was used to test short-term stability. The variations of total mercury concentration did not significantly differ between the intra and the inter-bottle (F=0.8, p=0.37). Additionally, relative standard deviation of the total mercury concentration showed low values (2.28%). For the short-term stability test, total mercury variations were not statistically significant as demonstrated by the result of the regression analysis (F ratio = 3.11, p = 0.18). This suggests that the cryogenic-milling process has statistically proven the degree of homogeneity and short-term stability for samples of carp muscles in the chemical analysis for total mercury.

• 한국인터넷방송통신학회논문지
• /
• 제19권5호
• /
• pp.79-85
• /
• 2019

본 연구에서는 Long Short Term Memory (LSTM) 신경망과 Gated Recurrent Unit(GRU) 신경망을 Internet of Things (IoT) 파워미터에 적용하여 단기 전력사용량 예측방법을 제안하고, 실제 가정의 전력사용량 데이터를 토대로 예측 성능을 분석한다. 성능평가 지표로써 Mean Absolute Error (MAE), Mean Absolute Percentage Error (MAPE), Mean Percentage Error (MPE), Mean Squared Error (MSE), Root Mean Squared Error (RMSE)를 이용한다. 실험 결과는 GRU 기반의 모델이 LSTM 기반의 모델에 비해 MAPE 기준으로 4.52%, MPE 기준으로 5.59%만큼의 성능개선을 보였다.

• 예술인문사회 융합 멀티미디어 논문지
• /
• 제9권3호
• /
• pp.747-756
• /
• 2019

통역을 학습하는 학생들은 수업 외에도 추가적인 학습 및 훈련을 수행한다. 동시통역 및 순차통역에서 두 언어의 구조가 다르기 때문에 통역가는 발표 내용을 빠르게 기억해야 한다. 단기 기억 향상을 위해서 통역을 학습하는 학생들은 메모리 훈련을 수행한다. 메모리 훈련은 파트너가 필요하기 때문에 학습 효율성이 저하되고 자가 학습이 불가능하다. 이를 해결하기 위해서 컴퓨터 기반의 단기 기억 훈련 시스템이 제안되었다. 지문 내 단어를 특수문자로 변경함으로써 학생들이 파트너 없이도 자가 학습이 가능하다. 하지만 컴퓨터는 휴대성이 떨어지기 때문에 외부에서는 학습 능률이 저하된다. 제거되는 단어보다 키워드로 제공하는 단어의 수가 더 많아서 학습 난이도가 저하된다. 이를 해결하기 위해서, 본 논문에서는 스마트 단말 기반의 문장구역 훈련 시스템을 제안하였다. 스마트 단말은 휴대성이 높아 학습의 제한이 없어 효율이 증가한다. 제안하는 훈련 시스템에서는 삭제되는 단어수가 키워드보다 더 많도록 하여 학습 난이도가 증가한다. 제안한 훈련 시스템을 구현하고 기능을 검증하였다.

• 대한통합의학회지
• /
• 제9권4호
• /
• pp.91-103
• /
• 2021

Purpose : This study aimed to evaluate the effects of a cognitive enhancement brain yoga program on short-term memory and serum brain-derived neurotrophic factor (BDNF) levels according to the cognitive state in men aged 20-29 years. Methods : Thirty healthy volunteers aged 20-29 years were divided into four groups: brain yoga group, yoga group, combined exercise group, and control group. Seven people were assigned randomly per group. A single-session intervention was conducted over 50 min and consisted of three parts: warm-up, main exercise (brain yoga, yoga, combined exercise, or non-exercise), and cool-down. Serum BDNF levels were measured using enzyme-linked immunosorbent assay, and short-term memory was evaluated using the forward number span test before and after the intervention. Results : BDNF levels significantly increased within the brain yoga group after the intervention (from 28874.37±5185.57 to 34074.80±7321.12, p=.003), whereas there were no significant differences pre-and post-intervention in the other groups. The inter-group comparison showed a significant interaction between the brain yoga group and the combined exercise group (p=.036) but no significant interaction between any of the other groups. Forward number span scores were significantly increased in the brain yoga group (from 9.43±9.83 to 23±7.92, p=.012) and theyoga group after the intervention (from 13.43±9.41 to 24.14±8.45, p=.011), whereas there were no significant changes after the intervention in any other groups. Conclusion : Our findings showed that a single-session, 50-minute brain yoga exercise improved short-term memory and increased serum BDNF levels in healthy men aged 20-29 years and that yoga improved only short-term memory in healthy men of this age group.

• 한국음향학회지
• /
• 제42권4호
• /
• pp.313-319
• /
• 2023

본 논문에서는 일부 소음 데이터만 알고 있을 때 결손된 데이터를 예측할 목적으로 수조에서 측정된 기포유동 소음 데이터와 수중 운동체 발사 소음 데이터를 시계열 기계학습 모델인 Long Short Term Memory(LSTM)에 적용해 보았다. 기포유동소음 데이터는 파이프에서 측정된 소음으로 기포소음, 유동소음, 유체기인소음이 혼합되어 있으며 유형별로 3가지로 분류할 수 있다. 수중 운동체 발사소음은 모형 발사튜브에서 수중 운동체가 사출될 때 발생하는 소음으로 순간소음이며 발사 이벤트마다 불규칙하게 변한다. 이러한 종류의 소음 생성을 위해서는 해석적인 모델보다는 데이터 기반 모델이 유용할 수 있다. 본 연구에서는 LSTM을 데이터 기반 모델을 만들었다. 모델에 영향을 주는 LSTM의 은닉유닛의 개수, 입력시퀸스의 개수, 데시메이션 인자에 따른 모델의 성능을 확인하고 최적의 LSTM 모델을 구성했다. 같은 유형은 새로운 데이터에 대해서도 잘 동작하는 것을 보였다.

• 운동영양학회지
• /
• 제15권4호
• /
• pp.173-182
• /
• 2011

Post-traumatic stress disorder (PTSD) is a stress-related mental disorder induced by severe external stressors such as assault, disaster or severe accident. We investigated the effects of treadmill exercise on short-term memory in relation to apoptosis and cell proliferation in the hippocampus following PTSD. Stress to the pregnant rats was induced by exposure of maternal rats to the hunting dog in an enclosed room. Exposure time was 10 min, repeated three times per day, with 1 hour interval. Exposure of maternal rats to the hunting dog was continued 7 days after pregnancy until delivery. The pregnant rats in the exercise groups were forced to run on a treadmill for 30 min once a day for the same duration of stress exposure. Step-down avoidance task for short-term memory, western blot for Bcl-2, Bax, and immunohistochemistry for caspase-3, 5-bromo-2'-deoxyuridine (BrdU), and Ki-67 were conducted. Maternal rats exposed to stress during pregnancy showed short-term memory impairment. Expressions of Bax, Bcl-2, ratio of Bax to Bcl-2, and caspase-3 in the hippocampus were increased in the PTSD rats. Cell proliferation in the hippocampal dentate gyrus was decreased in the PTSD rats. Treadmill exercise alleviated short-term memory impairment and suppressed expressions of Bax, the ratio of Bax to Bcl-2, and caspase-3. Treadmill exercise also increased cell proliferation. The present results indicate that treadmill exercise alleviated PTSD-induced short-term memory impairment by suppressing apoptotic cell death and enhancing cell proliferation in the hippocampus.

• 대한조선학회논문집
• /
• 제40권5호
• /
• pp.60-67
• /
• 2003

For risk or reliability assessment of ship structures against particular hazardous situations such as total loss or sinking due to hull girder collapse, the short-term based response analysis rather than the long-term response analysis is required to determine wave-induced bending moments when the ship encounters a storm of specific duration and with a specified small encounter probability. In the present study, the effects of operational condition and sea states on wave-induced bending moments of large merchant vessels are investigated. A series of the short-term response analyses for a hypothetical VLCC and a Capesize bulk carrier (CSBC) are carried out with varying operational condition and sea states which include ship speed, significant wave height and wave persistence time, using the linear-strip theory based program ABS/SHIPMOTION and the MIT sea-keeping tables. The computed results are also compared with the IACS design formula predictions. The results and insights developed from the present study are summarized.

• 콘크리트학회논문집
• /
• 제12권4호
• /
• pp.69-78
• /
• 2000

Creep of concrete is the most dominating factor affecting time-dependent deformations of concrete structures. Especially, creep deformation for design and construction in prestressed concrete structures should be predicted accurately because of its close relation with the loss in prestree of prestressed concrete structures. Existing creep-prediction models for special applications contain several impractical factors such as the lack ok accuracy, the requirement of long-term test and the lack of versatility for change in material properties, ets., which should be improved. In order to improve those drawbacks, a methodology to modify the creep-prediction equation specified in current Korean concrete structures design standard (KCI-99), which underestimates creep of concrete and does not consider change of condition in mixture design, is proposed. In this study, short-term creep tests were carried out for early-age concrete within 28 days after loading and their test results on influencing factors in the equation are analysed. Then, the prediction equation was modified by using the early-age creep test results. The modified prediction equation was verified by comparing their results with results obtained from long-term creep test.

• 대한한방내과학회지
• /
• 제36권4호
• /
• pp.458-469
• /
• 2015

Objectives: Buja and Cheono, containing aconitine known for its cardiotoxicity, are not commonly prescribed, but they are necessary for some clinical conditions. Hence, consequences for electrocardiography (EKG) after short- and long-term dosage of herbal medicine including Buja and Cheono are here reported.Methods: From September 2014 to April 2015, 36 patients belonging to the sixth internal medicine department of the Dong Eui Oriental Medicine Hospital took herbal medicine including Buja and Cheono, and after these doses, they underwent an EKG. Thirty-one patients who took the medicine for 7-8 days comprised the short-term group, and 18 patients taking the medicine for 17-106 days comprised the long-term group. The results of the EKGs for each group, before and after dosage with herbal medicine, are compared.Results: No significant changes in EKG appeared in either the short- or the long-term group after taking herbal medicine including Buja and Cheono.Conclusions: If Buja or Cheono are prescribed along with other suitable herbs by a doctor of Korean medicine, no cardiac trouble will occur on an EKG regardless of the term of the dosage.