고무물성에 미치는 국산 무기충진제의 효과에 관한 연구

장영재,김기주,강경호,김종석,안병국,서수교 한국고무학회 1989 엘라스토머 및 콤포지트 Vol.24 No.4

This study deals with both effects of inorganic fillers to vulcanized rubbers such as NR, CR, EPDM, NBR & SBR and inorganic characteristics of domestic fillers in comparision with hard clay produced in the USA. The results were as follows. 1. Main ingredient of domestic clay $quot;Ha-dong clay$quot; was Halloysite, $quot;No-ha Island$quot; was Pyrophyllite with α-Quartz, and both of $quot;Hard clay$quot; & $quot;Hwa-soon clay$quot; were proved to be Kaolinite by XRD, DT-TGA and chemical analysis by XRF. 2. Tensile strength value of SBR compounded with these fillers, was Hard clay 146㎏f/㎠, Kaolinite 123㎏f/㎠, Pyrophyllite 82㎏f/㎠, Halloysite 80㎏f/㎠, precipitated CaCO₃ 27㎏f/㎠, and ground CaCO₃ was 21㎏f/㎠. These results showed the increase of seven times according to filler species. 3. The physical properties of non-crystalline rubbers, such as SBR, NBR & EPDM, compared with NR & CR, have been considerably changed according to crystalline phase, particle size, shape and surface structure of fillers. Especially, tensile strength value in case of SBR & EPDM, was differentiated about 1.5 times by the particle size of fillers. 4. In SBR, physical properties of rubber compounded with Kaolinite which was surface treated with fatty acid and silane, almost approach to the value of hard clay. 5. Delayed cure time of Kaolinite and decrease of rubber properties by CaCO₃can be improved by blending kaolinite & CaCO₃ in the ratio of 2 : 1.

GNN-RL 방법론을 이용한 Flexible Job Shop Scheduling

장영재,강대묵 대한산업공학회 2020 대한산업공학회 추계학술대회논문집 Vol.2020 No.11

금융위기 이후 부실채권을 고려한 국내 은행의 비효율성과 생산성 변화

장영재,양동현 한국산학기술학회 2020 한국산학기술학회논문지 Vol.21 No.6

This study constructed production frontiers of inputs and outputs in a sequential manner, measured inefficiencies by applying a non-radial sequential weighted Russell directional distance function to these frontiers, and analyzed Luenberg productivity indices and the contribution of each of input and output factor based on these distances. The results are as follows. First, the productivity of banks increased due to technical changes after the global financial crisis. Second, productivity growth decreased between 2009 and 2014 due to technical changes after the recession, as previous studies have shown that technology progressed before the global financial crisis but then largely decreased or remained the same thereafter. After 2014, the productivity of banks improved. This result may be due to both technology improvement after 10 years of stagnation and reduction of inputs and non-performing loans. Third, the 3.6% annual of productivity growth for 10 years was comprised of 1.77% household loans, 0.67% corporate loans, 0.98% manpower, 1.18% non-performing loans, -0.5% total deposits, and -1.25% securities. Finally, this study has limitations since it could not control risks such as capital structure and interest volatility. 본 연구는 연도별 은행의 투입요소와 산출요소의 생산가능집합을 순차적인 방법으로 구성하고 이 프런티어에 의해 비방사형 순차적 가중평균 러셀 방향거리함수로 비효율성을 측정한 후, 거리함수 값을 기초로 은행별 루엔버거 생산성 지수와 각 투입산출요소별 생산성 변화의 기여도를 분석하였다. 분석결과 첫째, 은행의 생산성은 글로벌 금융위기 이후 기술변화의 영향으로 생산성이 증가하였다. 둘째, 선행연구에서 글로벌 금융위기 전까지 기술진보의 변화를 보였으나 그 이후 기술변화는 정체 상태임을 실증적으로 제시하였다. 본 연구에서도 2009년부터 2014년까지는 기술변화의 침체로 생산성은 마이너스 성장을 하였다, 그러나 2014년 이후 생산성이 증가하였는데, 그 원인은 정체상태에 있었던 기술변화가 투입요소와 무수익여신의 감소로 인하여 기술진보로 전환된 데 있으며 이로 인해 생산성이 증가된 것으로 추론된다. 셋째, 과거 10년간 은행의 생산성 지수는 연평균 3.6% 증가하는 변화를 보였는데, 각 투입 및 산출요소별 생산성 기여도는 가계대출액 1.77%, 기업대출액 0.67%, 유형자산 1%, 인력 0.98%, 무수익여신 1.18%, 증권투자액과 총수신액 각각 –1.25%, -0.5%로 생산성을 증가시키는 데 무수익여신의 감축이 중요한 비중을 차지하고 있다. 본 연구의 한계점으로 분석모형의 방향성 거리함수 측정과정에서 자본구조 위험, 유동성 위험 등 환경변수의 방향성 설정이 어렵기 때문에 모형 내에서 통제하지 못함에 따라 환경변수의 영향을 고려하지 못하였다.

A Study on Urban Change Detection Using D-DSM from Stereo Satellite Data

장영재,오관영,이광재,오재홍 한국측량학회 2019 한국측량학회지 Vol.37 No.5

Unlike aerial images covering small region, satellite data show high potential to detect urban scale geospatial changes. The change detection using satellite images can be carried out using single image or stereo images. The single image approach is based on radiometric differences between two images of different times. It has limitations to detect building level changes when the significant occlusion and relief displacement appear in the images. In contrast, stereo satellite data can be used to generate DSM (Digital Surface Model) that contain information of relief-corrected objects. Therefore, they have high potential for the object change detection. Therefore, we carried out a study for the change detection over an urban area using stereo satellite data of two different times. First, the RPC correction was performed for two DSMs generation via stereo image matching. Then, D-DSM (Differential DSM) was generated by differentiating two DSMs. The D-DSM was used for the topographic change detection and the performance was checked by applying different height thresholds to D-DSM.

시험인증 기술동향 - 유헬스 의료기기 시스템의 상호운용성 평가기술 개발 방안

장영재,이강해,차지훈,허잔회,박기정,Jang, Yeong-Jae,Lee, Gang-Hae,Cha, Ji-Hun,Heo, Jan-Hoe,Park, Gi-Jeong 한국정보통신기술협회 2011 TTA저널 Vol.138 No.-

의료 기록카드제도의 연구 /

장영재 大邱大學校 東西歐問題硏究所, 1990 歐洲論叢 Vol.5 No.1

응급의료센터를 방문한 성인 급성 충수염 환자에서 재실 기간의 연장을예측하는 인자에 대한 비교연구

장영재,김신영,홍대영,백광제,박상오,김종원,김진용,이경룡 대한응급의학회 2018 대한응급의학회지 Vol.29 No.6

Objective: This study examined the predictive factors for prolonged length of stays of adult patients with acute appendicitis (AA) in an emergency department (ED). Methods: This was a retrospectively clinical study including patients in an ED. All patients were diagnosed from the clinical symptoms and a typical physical examination, and had undergone a computed tomography (CT) evaluation on the ED visiting date. All data were collected from the electrical medical records. The clinical parameters analyzed were the laboratory data, including the white blood cell count with differential values, C-reactive protein (CRP) level, initial vital signs, duration of admission, coexisting perforation of the appendix in the CT findings. The relationship between the clinical parameters and length of stay was assessed. Results: A total of 547 patients with AA were enrolled in this study. Among them, there were 270 male patients with a mean age of 40.7±15.8 years. The baseline characteristics, initial clinical features, laboratory, and imaging studies results of 129 patients in the prolonged length of stay (pLOS) group, and 418 patients of the non-pLOS group in AA were compared. Multivariable logistic regression analysis revealed the predictive factors related to pLOS in AA to be as follows: age 40 years or older, body temperature over 37.3 C, CRP level greater than 5.0 mg/dL, and evidence of perforation in CT findings (P<0.001). Conclusion: If we check age, fever, CRP level and find evidence of perforation, it might be helpful for predicting the increasing period of length of hospital stay for patients with AA in ED.

GDP갭 분해기법을 이용한 변동요인 분석

장영재,Chang, Youngjae 한국통계학회 2014 응용통계연구 Vol.27 No.3

GDP갭(gap)이란 잠재GDP와 실제GDP의 격차로서 산출갭(Output gap)이라고도 한다. 잠재GDP는 노동, 자본 등 생산요소를 완전히 활용하여 달성할 수 있는 최대GDP라고 정의할 수 있다. GDP갭은 수요-공급간 불균형을 의미한다고 할 수 있으며 이러한 특성 때문에 물가 및 고용안정을 추구하는 중앙은행들은 정책수행과정에서 GDP갭을 중요한 정보변수로 활용하고 있다. 본 연구에서는 우리나라의 GDP갭을 그간 선행연구에서 사용하였던 필터링 방법에 의해 분해함으로써 GDP갭 변동을 야기하는 주요 요인이 무엇인지 살펴보았다. Fox 등 (2003)와 Fox와 Zurlinden (2006)에서 사용되었던 Super Smoother 알고리즘을 이용하여 우리나라의 명목GDP갭을 분해해 본 결과 이론적인 설명에 부합하는 것으로 나타났다. 명목GDP갭률 변동의 상당부분은 잔차인 총요소생산성으로 설명됨을 알 수 있었는데, 이는 최근들어 급격한 기술변화 및 환경변화 등 생산성 변화가 GDP변동에 큰 영향을 주고 있음을 의미한다. 다른 나라의 경우와 마찬가지로 국내물가의 영향력도 높은 것으로 나타났지만 대외 의존도가 높은 우리 경제의 특성상 교역조건의 변동 역시 상대적으로 명목GDP 움직임에 큰 영향을 주고 있는 것으로 분석되었다. The GDP gap (also called the output gap) is the difference between potential GDP and actual GDP. Potential GDP is the maximum sustainable output that is achieved when the resources (labor and capital) are used to capacity. Central banks pursuing price and employment stability consider the output gap as an informative variable for monetary policy since the output gap could be regarded as a proxy of demand-supply imbalances. In this paper, the GDP gap of Korea is decomposed following the filtering method in the previous research, and major factors that affect the variation of GDP gap are investigated based on the decomposed series. The analysis results by the Super Smoother algorithm used in Fox et al. (2003)and Fox and Zurlinden (2006) are found consistent with theory. Much of the variation of nominal GDP gap is explained by Total Factor Productivity(TFP) gap, which is the change of productivity due to recent technological innovation and environmental change. It is also found that variation of terms of trade significantly affects the GDP gap of Korea due to its high dependency on international trade; however, the effect of the domestic price is not negligible like other countries.

Topographic Information Extraction from Kompsat Satellite Stereo Data Using SGM

장영재,이재왕,오재홍 한국측량학회 2019 한국측량학회지 Vol.37 No.5

DSM (Digital Surface Model) is a digital representation of ground surface topography or terrain that is widely used for hydrology, slope analysis, and urban planning. Aerial photogrammetry and LiDAR (Light Detection And Ranging) are main technology for urban DSM generation but high-resolution satellite imagery is the only ingredient for remote inaccessible areas. Traditional automated DSM generation method is based on correlation-based methods but recent study shows that a modern pixelwise image matching method, SGM (Semi-Global Matching) can be an alternative. Therefore this study investigated the application of SGM for Kompsat satellite data of KARI (Korea Aerospace Research Institute). Firstly, the sensor modeling was carried out for precise ground-to-image computation, followed by the epipolar image resampling for efficient stereo processing. Secondly, SGM was applied using different parameterizations. The generated DSM was evaluated with a reference DSM generated by the first pulse returns of the LIDAR reference dataset.

GDP갭의 물가영향력 변화 분석

장영재,Chang, Youngjae 한국데이터정보과학회 2015 한국데이터정보과학회지 Vol.26 No.6

한 나라 전체의 경제활동 수준을 나타내는 경기의 변동과 밀접한 관계를 지닌 지표로서 GDP갭을 꼽을 수 있다. GDP갭은 초과수요압력이나 고용사정에 대한 정보를 제공하기 때문에 중앙은행의 통화정책 수행시 중요한 고려변수로 꼽히고 있다. 그러나, GDP갭 총량만으로는 최근의 경제구조 변화라든지 대내외 경제여건의 영향 등을 살펴볼 수 없는 등 제한적인 부분이 있다. 본 논문에서는 통계적 필터링 기법에 의해 새로운 갭을 추정하고 다양한 물가영향 모형을 설정하여 각 요인들이 인플레이션에 미치는 영향력을 추정하는 한편 동 요인들의 영향력이 시간에 따라 변화하는지도 분석하였다. 분석결과, GDP갭의 물가영향력이 2000년대 들어 대체로 그 영향력이 축소되는 것으로 추정된 반면, 글로벌갭이 국내 물가에 미치는 영향력은 증대된 것으로 나타났다. 이러한 변화는 최근의 저물가 현상이 국내요인과 더불어 세계 경기침체에서 비롯된 수출의 둔화와 같은 국외여건에 영향을 받았다는 것을 의미한다. GDP gap is closely related with economic activity of a country as a whole, especially with the economic fluctuations which is called business cycle. GDP gap is regarded as an important variable for the monetary policy of the central bank because it provides information on the excess demand pressures and employment matters. However, GDP gap may not provide enough information of the effect of recent economic structural change or the environmental change of domestic and external economic condition. In this paper, the GDP is decomposed by statistical filtering techniques and various models are fitted to estimate the influence of GDP gap on Inflation and see if it has been changed. Analysis results show that the influence of GDP gap on inflation decreased in the 2000s while that of global GDP gap increased. These results also support that recent low inflation rate is due to the change of overseas economic condition, such as a slowdown in exports resulting from the global recession, as well as domestic factors.