불균형 패널 데이터를 이용한 제조업 영역 및 시간별 에너지 효율성 분석

이가현,송병훈,전현우 대한산업공학회 2023 대한산업공학회 춘계학술대회논문집 Vol.2023 No.5

Since the manufacturing industry accounts for a significant portion of the total industrial energy consumption, addressing energy efficiency in the manufacturing sector is crucial. Energy efficiency can be analyzed through comparative studies between evaluated efficiency values, and it is important to assess manufacturing energy efficiency by sectors and time. The Industrial Assessment Center (IAC) database provides valuable information on energy use and production for companies within specific manufacturing sectors, including time. Therefore, the IAC database can be utilized to analyze the energy efficiency of manufacturing by sector and time. Popular efficiency evaluation methods such as Data Envelopment Analysis (DEA) and Stochastic Frontier Analysis (SFA), however, are suitable for cross-sectional data or balanced panel data, but the IAC database provides only unbalanced panel data. Thus, we propose a new approach based on SFA to evaluate manufacturing energy efficiency by sector and time, using the IAC database. Specifically, we classify the entire manufacturing industry into 20 sectors based on the Standard Industrial Classification (SIC) code. Then, we apply the Gamma SFA model to the IAC database to evaluate the energy inefficiency values of all manufacturing firms. After that, we compare and analyze the averaged energy inefficiency values by each manufacturing sector and year. The results of our proposed method show that annual energy efficiency in most manufacturing sectors was improved by around 2010. Additionally, textile sector was identified as the most inefficient sector, while petroleum and coal products sector was the most efficient area.

뇌전증지속상태의 치료

이가현,정대수 대한신경집중치료학회 2016 대한신경집중치료학회지 Vol.9 No.1

Status epilepticus is a severe neurological disease associated with substantial mortality and health-care cost. Treatment of status epilep- ticus should proceed without delay even in the pre-hospital setting because prolonged generalized convulsive seizures may lead to neu- ronal injury, pharmacoresistance, and poor prognosis. These concepts have led to the establishment of an updated treatment algorithm emphasizing a more rapid escalation to third-line therapy for refractory convulsive status epilepticus. This article reviews the guidelines and current evidence for the management of status epilepticus.

수입가격을 고려한 고등어 가격의 유통단계별 인과성과 비대칭적 가격 전이 분석

이가현,김도훈 한국식품유통학회 2023 食品流通硏究 Vol.40 No.1

This study analyzed the causality and asymmetric price transmission(APT) phenomenon among import, producer, wholesale, and retail prices of Chub Mackerel(Scomber japonicus). Chub Mackerel is one of major fish species in production and consumption in Korea. Meanwhile, the problem of rising retail prices has recently emerged, the research on the price structure of Chub Mackerel is needed. In the analysis, APT was estimated using the Nonlinear Autoregressive Distributed Lag(NARDL) model. As a result, the import price had a significant effect on retail price and asymmetric price transitions occurred overall at all distribution stages. In particular, a total of 12 APT phenomena were found, and front distribution stage was sensitive to the decrease in the price of the rear distribution stage and the rear distribution stage was more sensitive to the increase in the price of the front distribution stage.

동아시아 SF X BL 서사의 트랜스-휴머니즘적 상상력과 젠더⋅섹슈얼리티 실험

이가현,류호현 한국중국소설학회 2022 中國小說論叢 Vol.67 No.-

This study is part of an attempt to grasp the popularization of BL (Boys’ Love) culture as a subculture trend, a kind of Trans-East Asian cultural phenomenon. Along with the changes in the contexts surrounding BL culture, BL culture moves its ground from exclusive enthusiast fandom community to more open and public popular culture market. With increasing popularity, BL is rapidly expanding its boundary and influence in terms of contents, genre, channel, and related industrial ecosystem. Among various aspect of genre expansion of BL, this study focuses on the ‘BL + X (or X + BL)’, the combination of BL with other genre elements. This study gives close attention to the combination of BL and SF. SF is gaining a whole new vitality and strength in line with the rise of the 4th Industrial Revolution. Recently, it is recognizable that the combination of these two genres has been frequent and vigorous. The vigorous combination of SF and BL seems to be due to the possibility of maximizing complementary synergy. In order to embrace BL, SF is dismantling the existing way of existence of ‘human’ and more boldly developing trans-humanistic imagination about the ‘not real but possible’ way of ‘human’ existence. Meanwhile, BL is more aggressively practicing the experiments about gender and sexuality in the world SF make possible, in which it is free from various existing norms (especially the gender norms). Erotic coupling between male figures (boys or men), the most essential element of BL culture, is bound to face various ethical challenges in real world. To avoid or neutralize these ethical challenges, BL combines with SF. This is because it enables the expansion of the ‘playground’ itself or the setting of a completely new version of it. In other words, the combination of SF and BL pushes the boundaries of subversive thinking inherent to the two genres to the very limit and enables a new imagination of humans and the world surrounding. 본 연구는 BL문화의 대중화를 한⋅중⋅일을 포함한 동아시아에서 동시대적으로 발생하고 있는 서브컬처 트렌드, 일종의 트랜스-동아시아적인 문화 현상으로 파악하고 그 다양한 양상과 의미를 파악하려는 시도의 일환이다. BL 문화가 대중화되고 음지의 서브컬처에서 양지로 점차 자신의 활동 영역을 넓힘에 따라, BL은 내용적 장르적 측면, 대중과의 접촉면, 산업생태계 측면 등 다방면으로 그 외연을 빠르게 확장하고 있다. 본 연구는 BL이 확장되고 있는 여러 면모들 중에 특히 ‘BL + X(혹은 X + BL)’의 양상, 즉 BL과 다른 장르적 요소의 결합을 통한 장르 확장이라는 측면에 초점을 맞추었다. 특히 4차 산업혁명의 거대한 조류와 맞물려 이전과는 또 다른 생명력을 얻고 있는 SF 장르와 BL의 결합을 주목했다. 최근 SF와 BL 두 장르의 결합은 대단히 활발하게 일어나고 있다. 본문은 SF와 BL이 적극적으로 결합하는 것은 이 결합이 상보적 시너지를 극대화할 수 있는 가능성을 가지고 있기 때문인 것으로 파악한다. 즉 SF와 BL의 결합은 두 장르 본연의 전복적 사고의 경계를 한계까지 밀어붙이며 인간과 인간을 둘러싼 세계에 대한 새로운 상상을 가능하게 한다.

SK社의 T MAP 내비게이션 목적지 설정 자료를 활용한 중력모형 근거 국내여행 수요모형 개발에 관한 연구

이가현,엄서호 국토연구원 2009 국토연구 Vol.61 No.-

This study applies the conventional gravity model to develop domestic travel demand model and to identify determinants influencing spatial interaction using SK T Map Navigation Data. Physical distance from a origin to a destination was used as a constrained variable in the travel demand model. The trip-generating power of an origin was measured by both population size and the GRDP(Gross Regional Domestic Products) while the trip-attracting power was measured by the square meters of accommodation and restaurant space at a destination. Empirical Analysis identified that gravity model was very appropriate to describe special interactions showing .92 R square. The distance variable had a negative sign as expected theoretically. The elasticity of the distance variable shows -1.113 next to the square meters of accommodation and restaurant space(1.499), the most effective determinant variable in the domestic travel demand model. 본 연구는 구조모형의 하나인 중력모형을 가지고 자동차 여행과 밀접한 관련이 있는 SK社의 T MAP 내비게이션 목적지 설정자료를 활용하여 국내여행 동태를 파악하고, 관광추진인자, 유인인자, 억제인자의 계수정산 과정을 거쳐 국내여행 수요모형을 개발하고자 한다. 수요함수에서 억제변수로는 물리적 거리변수를 적용하였으며, 여행발생지의 추진변수로는 인구수와 소득을 나타내는 변수인 지역내총생산을, 목적지의 유인변수로 개발 정도를 나타내는 숙박 및 음식점 면적을 적용하여 분석하였다. 그 결과 중력모형의 거리변수는 통계적으로 유의한 음(-)의 부호를 가져 기본가정에 부합하는 결과를 보였으며 R 제곱도 .92로 나타나 높은 설명력을 보였다. 거리의 탄성력은 -1.113로, 가장 높은 영향력을 나타내는 숙박 및 음식점 면적(1.499)보다 약간 낮게 나타났다. 또한 인구수, 지역내총생산도 통계적으로 유의하게 나타났다.

딥러닝 기법을 활용한 양식산 조피볼락 산지가격 예측 연구 -LSTM(Long-short Term Memory)과 GRU(Gated Recurrent Units) 모델을 중심으로-

이가현,김도훈 한국식품유통학회 2022 食品流通硏究 Vol.39 No.4

This study is aimed to forecast the producer price of aquaculture seafood using LSTM(Long-short Term Memory) and GRU(Gated Recurrent Units) models, a type of deep learning model. Since the producer price is directly related to aquacultural farm’s profitability, accurate forecasting of the producer price is essential to establish an effective production and management plan for aquaculture and stabilize supply and demand of farmed seafood. Korean Rockfish(Sebastes schlegelii) is a commercially important fish species that ranks second in domestic farmed fish production and is the main breed of fish farms in Tongyeong region. As the volatility of the producer price of Korean Rockfish has recently intensified, the importance of forecasting the producer price is increasing. In the analysis, total 19 variables were used, including producer prices in other regions, production-related variables, consumption-related variables, alternative farmed fish variables, water temperature, and COVID-19 dummy variables. Total 189 monthly data from October 2006 to June 2022 were used. In this study, the producer price of farmed Korean Rockfish was forecasted by LSTM and GRU models, a type of RNN(Recurrent Neural Network) model specialized for time series forecasting and the accuracy of models was compared with MAPE(Mean Absolute Percent Error). Results showed that MAPEs of LSTM and GRU were 4.66% and 6.27%, respectively. In addition, when comparing the accuracy by the number of independent variables, it was found that the accuracy of the multivariate LSTM model was better than that of the univariate LSTM model.

Warfarin-Induced Intracerebral Hemorrhage Associated with Microbleeds

이가현,권순억,강동화 대한신경과학회 2008 Journal of Clinical Neurology Vol.4 No.3

Background:Microbleeds (MBs), proposed as a biomarker for microangiopathy, have been suggested as a predictor of spontaneous or thrombolysis-related intracerebral hemorrhage (ICH) in acute ischemic stroke. However, the relationship between MBs and warfarin-induced ICH is not clear. Case Report:We describe two patients who developed warfarin-induced ICH at the site of MBs documented in previous MRI. Conclusions:The presence of MBs might increase the risk of ICH after warfarin use in ischemic stroke patients. A large cohort study is required to confirm the relationship of MBs with warfarin-induced ICH.

Cefepime에 의해 발생한 비경련성 간질 중첩증

이가현 부산대학교 병원 암연구소 2014 부산대병원학술지 Vol.- No.36

대구지역 택배서비스업 종사자의 디젤엔진배출물 노출 평가

이가현,김승원 한국산업보건학회 2017 한국산업보건학회지 Vol.27 No.4

Objectives: This study evaluated the diesel engine exhaust (DEE) exposure levels of door-to-door deliverers in Daegu from July to September. Methods: We measured exposure levels of DEE surrogates for the same door-to-door deliverers who joined the particulate matter 2.5 exposure study previously published in this journal. Black carbon(BC) concentrations were measured using real-time BC monitoring devices with 1 minute interval. NO2 concentrations were monitored using passive badges. DEE exposure data were analyzed using the same characteristics and GPS information as the first study. Results: A total of 40 measurements of BC concentrations and NO2 concentrations were collected during delivery of parcels. The average exposure levels to BC, and NO2 were 2.23 μg/m3(0.001—350.85 μg/m3) and 21.26 ppb(3.3—61.37 ppb), respectively. Exposure levels to BC according to the day of a week and coverage areas were not significantly different(p>0.05). Delivery trucks manufactured before 2006 caused significantly higher exposure to BC than the trucks manufactured after 2006(p<0.05). Exposure levels of BC integrated for each time in residential area and roadsides were 1.96 μg/m3 and 3.46 μg/m3, respectively, and the difference was statistically significant(p<0.001). The Pearson correlation coefficients between the ambient PM2.5 and BC was significant, r=0.26(p<0.01); however, the correlations between PM2.5 and ambient PM2.5, and between BC of DEE and PM2.5 of DEE did not show a significant correlationConclusions: BC and NO2 exposure levels were significantly lower when door-to-door deliverers drove newer trucks. BC exposure levels of deliverers were higher in roadsides than in residential area. DEE from nearby vehicles through open windows might be the main source of BC exposure.

Cellulose-graft-poly(l-lactide) micelle for drug delivery vehicle

이가현,이성준,정상원,김은주,김현철,서송이,최진현,이세근 한국고분자학회 2013 한국고분자학회 학술대회 연구논문 초록집 Vol.2013 No.4