• 제목/요약/키워드: Technology change

검색결과 14,449건 처리시간 0.041초

주파수 도메인 반사파 측정법을 이용한 플라즈마 공정장비 상태변화 연구 (Status Change Monitoring of Semiconductor Plasma Process Equipment)

  • 이윤상;홍상진
    • 반도체디스플레이기술학회지
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    • 제23권1호
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    • pp.52-55
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    • 2024
  • In this paper, a state change study was conducted through Frequency Domain Reflectometry (FDR) technology for the process chamber of plasma equipment for semiconductor manufacturing. In the experiment, by direct connecting the network analyzer to the RF matcher input of the 300 mm plasma enhanced chemical vapor deposition (PECVD) chamber, S11 was measured in a situation where plasma was not applied, and the frequency domain reacting to the chamber state change was searched. Response factors to changes in the status, such as temperature, spacing of the heating chuck, internal pressure difference, and process gas supply state were confirmed. Through this, the frequency domain in which a change in the reflection value was detected through repeated experiments. The reliability of the measured micro-displacement was verified through reproducibility experiments.

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제조업 고용구조변화의 특징 분석 (Structural Change and Employment in Manufacturing Sector -Polarization by Firm Size-)

  • 고상원
    • 기술혁신연구
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    • 제7권1호
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    • pp.14-35
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    • 1999
  • This paper presents the relationship between the pace of structural change and the magnitude of employment growth in the manufacturing sector in OECD countries. To measure the pace of structural change, the compositional change index in value-added in manufacturing sector is introduced. For mid to long-term there seems to be a positive relationship between the pace of structural change and the magnitude of employment growth. In those countries with higher value of the compositional index, the employment growth in manufacturing sector was generally higher. To analyse the characteristics of structural change in manufacturing sector, this paper classifies manufacturing industries into groups: one based on technology, one on orientation, one on wages and one on skills. The international comparison of manufacturing sector's employment patterns based on above four classifications are presented. International comparison suggests that Korean manufacturing sector move into jobs with more skills and knowledge The structural change of SMEs and large firms are compared based on above four classification methods. It is shown that SMEs' employment in low value sectors, that is low-technology, labor-intensive, tow-wage, and unskilled sectors, have risen faster than SMEs' employment in high-technology, science-based, high-wage and skilled sectors. Large firms' employment have been mainly increased in high value sectors. However, the employment growth of both large and small firms have been concentrated on production worker-intensively-using sectors, i.e. unskilled sectors. This widened the wage differential of production workers by firm sizes and concurrently led to severe shortage of production workers for SMEs, which has little ability to pay high wage to production workers because they usually belong to low-wage sectors. Korea need to push SMEs forward to high value sectors. The premise of that is, however, to pull large firms out of production worker-intensively-using sectors.

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잠열물질을 이용한 열저장 기술에 관한 연구 (Study of Thermal Storage Technology using Phase Change Material)

  • 김정열;정동열;박동호;백종현
    • 융복합기술연구소 논문집
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    • 제2권1호
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    • pp.1-6
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    • 2012
  • The cold chain system in South-East Asia is requiring to maintain freshness of refrigerated or frozen food. In this study, Thermal storage system using Phase change material (PCM) was developed and evaluated its performance about temperature and cold keeping time. For various application of cold chain system, we developed portable cold box, cold roll container and freezing station. Keeping time on laboratory tests of portable cold box in case of refrigeration and freezing were 6 hours and 4 hours, respectively. Cold container was developed to 2.5 ton scale. Evaluation in Indonesia, it was showed to keep the setting temperature of $-10^{\circ}C$ over 40 hours at $30^{\circ}C$ of ambient air. Freezing station using PCM was kept over 24 hours under $-20^{\circ}C$.

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Analysis of future flood inundation change in the Tonle Sap basin under a climate change scenario

  • Lee, Dae Eop;Jung, Sung Ho;Yeon, Min Ho;Lee, Gi Ha
    • 농업과학연구
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    • 제48권3호
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    • pp.433-446
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    • 2021
  • In this study, the future flood inundation changes under a climate change were simulated in the Tonle Sap basin in Cambodia, one of the countries with high vulnerability to climate change. For the flood inundation simulation using the rainfall-runoff-inundation (RRI) model, globally available geological data (digital elevation model [DEM]; hydrological data and maps based on Shuttle elevation derivatives [HydroSHED]; land cover: Global land cover facility-moderate resolution imaging spectroradiometer [GLCF-MODIS]), rainfall data (Asian precipitation-highly-resolved observational data integration towards evaluation [APHRODITE]), climate change scenario (HadGEM3-RA), and observational water level (Kratie, Koh Khel, Neak Luong st.) were constructed. The future runoff from the Kratie station, the upper boundary condition of the RRI model, was constructed to be predicted using the long short-term memory (LSTM) model. Based on the results predicted by the LSTM model, a total of 4 cases were selected (representative concentration pathway [RCP] 4.5: 2035, 2075; RCP 8.5: 2051, 2072) with the largest annual average runoff by period and scenario. The results of the analysis of the future flood inundation in the Tonle Sap basin were compared with the results of previous studies. Unlike in the past, when the change in the depth of inundation changed to a range of about 1 to 10 meters during the 1997 - 2005 period, it occurred in a range of about 5 to 9 meters during the future period. The results show that in the future RCP 4.5 and 8.5 scenarios, the variability of discharge is reduced compared to the past and that climate change could change the runoff patterns of the Tonle Sap basin.

철도차량 본선 운행선로 시운전에 관한 요건 분석 (Analysis of Requirements for Testing Operation of the Rolling Stock on the Main Line)

  • 최경진;양도철;최강윤
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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    • pp.2286-2291
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    • 2011
  • Technology on the rolling stock is very composition and system engineering. We have to consider to many parameters on the rolling stock design. High speed train is interface between rolling stock and infra system of rail, signal, communication etc. For many years testing operation has experienced substantial growth based on various advanced new technology. Recently some problems was clearly stated on effective management, practical use and testing operation of the the rolling stock on the technology change. This paper presents some results of the study on necessary requirements of the operation testing for rolling stock technology change. We propose a general plan to suggest the operation testing and the parameters of the rolling stock on the technology change in the text.

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Streamflow sensitivity to land cover changes: Akaki River, Ethiopia

  • Mitiku, Dereje Birhanu;Kim, Hyeon Jun;Jang, Cheol Hee;Park, Sanghyun;Choi, Shin Woo
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2016년도 학술발표회
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    • pp.49-49
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    • 2016
  • The impact of land cover changes on streamflow of the Akaki catchment will be assessed using Soil and Water Assessment Tool (SWAT) model. The study will analyze the historical land cover changes (1993 to 2016) that have taken place in the catchment and its effect on the streamflow of the study area. Arc GIS will be used to analysis the satellite images obtained from the United States Geological Survey (USGS). To investigate the impact of land cover change on streamflow the model set up will be done using readily available spatial and temporal data, and calibrated against measured discharge. Two third of the data will be used for model calibration (1993?2000) and the remaining one-third for model validation (2001?2004). Model performance will be evaluated by using Nash and Sutcliff efficiency (NS) and coefficient of determination (R2). The calibrated model will be used to assess two land cover change (2002 and 2016) scenarios and its likely impacts of land use changes on the runoff will be quantified. The evaluation of the model response to these changes on streamflow will be presented properly. The study will contribute a lot to understand land use and land cover change on streamflow. This enhances the ability of stakeholder to implement sound policies to minimize undesirable future impacts and management alternatives which have a significant role in future flood control of the study area.

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Pork Quality Traits According to Postmortem pH and Temperature in Berkshire

  • Kim, Tae Wan;Kim, Chul Wook;Yang, Mi Ra;No, Gun Ryoung;Kim, Sam Woong;Kim, Il-Suk
    • 한국축산식품학회지
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    • 제36권1호
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    • pp.29-36
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    • 2016
  • This study was performed to investigate the role of pH and temperature postmortem, and to demonstrate the importance of these factors in determining meat quality. Postmortem pH45min (pH at 45 min postmortem or initial pH) via analysis of Pearson’s correlation showed high positive correlation with pH change pHc24 (pH change from pH45min to pH24h postmortem). However, postmortem pH after 24 h (pH24h or ultimate pH) had a high negative correlation with pH change, pHc24, CIE L*, and protein content. Initial temperature postmortem (T1h ) was positively associated with a change in temperature from 45 min to 24 h postmortem (Tc24) and cooking loss, but negatively correlated with water holding capacity. Temperature at 24 h postmortem (T24h) was negatively associated with Tc24. Collectively, these results indicate that higher initial pH was associated with higher pHc24, T1h, and Tc24. However, higher initial pH was associated with a reduction in carcass weight, backfat thickness, CIE a* and b*, water holding capacity, collagen and fat content, drip loss, and cooking loss as well as decreased shear force. In contrast, CIE a* and b*, drip loss, cooking loss, and shear force in higher ultimate pH was showed by a similar pattern to higher initial pH, whereas pHc24, carcass weight, backfat thickness, water holding capacity, fat content, moisture content, protein content, T1h, T24h, and Tc24 were exhibited by completely differential patterns (p<0.05). Therefore, we suggest that initial pH, ultimate pH, and temperatures postmortem are important factors in determining the meat quality of pork.

우리나라의 기후변화적응 국제협력에 대한 고찰 (Investigation on Enhancing Efficiency in International Cooperation for Climate Change Adaptation of Republic of Korea)

  • 박용하;정서용;손요환;이우균
    • 한국기후변화학회지
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    • 제1권2호
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    • pp.179-188
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    • 2010
  • 우리나라는 유엔 기후변화 협약 상 온실가스 저감과 함께 중요하게 다뤄지고 있는 기후변화적응 문제에 대응하기 위해, 2010년에는 국가기후변화적응대책(2011~2015)의 마련 추진 등 구체적인 기후변화적응체계를 갖추어 나가고 있다. 기후변화적응에 관한 우리의 역량을 선진 외국의 정책 및 관련 도구개발 기술 등과 비교할 때, 기후변화 관련 기반의 정보 부족, 전문 연구 인력의 부족, 기후변화 취약성 평가기술 부족 등 여러 부문에서 한계가 있다. 그러나 기후변화적응과 관련된 우수한 정보체계, 상대적으로 높은 기후변화적응기술을 보유하고 있는 강점이 있다. 2009년 7월에는 기후변화적응 전문연구조직인 한국환경정책?평가연구원/국가기후변화적응센터가 마련되었고, 국가의 기후변화적응능력과 동아시아 등 기후변화에 취약한 국가들을 지원하기 위한 우리나라의 능력을 높이고 있다. 기후변화적응정책 및 기술개발이 환경산업과 밀접하게 맞물려 있음을 볼 때, 이 부문에 대해 우리나라가 추진하는 아시아 지역 개도국들에 대한 협력 및 기술지원 등은 장기적인 투자의 밑거름이라 볼 수 있다. 아시아 지역 국가들과의 기후변화적응 국제협력은 사업-연구-교육-국제 동반자 체계를 묶는 상호보완적인 통합형의 국제협력을 고려할 수 있다. 또한, 개도국과 세계적 관심을 끌 수 있는 공동의 문제를 발굴하여 함께 해결하는 동반자 및 랜드 마크형의 상호 국제협력 등은 효과적이며 지속적으로 추진할 수 있는 사업이 될 것이다.

Neural Network Modeling supported by Change-Point Detection for the Prediction of the U.S. Treasury Securities

  • Oh, Kyong-Joo;Ingoo Han
    • 한국경영과학회:학술대회논문집
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    • 한국경영과학회 2000년도 추계학술대회 및 정기총회
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    • pp.37-39
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    • 2000
  • The purpose of this paper is to present a neural network model based on change-point detection for the prediction of the U.S. Treasury Securities. Interest rates have been studied by a number of researchers since they strongly affect other economic and financial parameters. Contrary to other chaotic financial data, the movement of interest rates has a series of change points due to the monetary policy of the U.S. government. The basic concept of this proposed model is to obtain intervals divided by change points, to identify them as change-point groups, and to use them in interest rates forecasting. The proposed model consists of three stages. The first stage is to detect successive change points in the interest rates dataset. The second stage is to forecast the change-point group with the backpropagation neural network (BPN). The final stage is to forecast the output with BPN. This study then examines the predictability of the integrated neural network model for interest rates forecasting using change-point detection.

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An Integrated Approach Using Change-Point Detection and Artificial neural Networks for Interest Rates Forecasting

  • Oh, Kyong-Joo;Ingoo Han
    • 한국지능정보시스템학회:학술대회논문집
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    • 한국지능정보시스템학회 2000년도 춘계정기학술대회 e-Business를 위한 지능형 정보기술 / 한국지능정보시스템학회
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    • pp.235-241
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    • 2000
  • This article suggests integrated neural network models for the interest rate forecasting using change point detection. The basic concept of proposed model is to obtain intervals divided by change point, to identify them as change-point groups, and to involve them in interest rate forecasting. the proposed models consist of three stages. The first stage is to detect successive change points in interest rate dataset. The second stage is to forecast change-point group with data mining classifiers. The final stage is to forecast the desired output with BPN. Based on this structure, we propose three integrated neural network models in terms of data mining classifier: (1) multivariate discriminant analysis (MDA)-supported neural network model, (2) case based reasoning (CBR)-supported neural network model and (3) backpropagation neural networks (BPN)-supported neural network model. Subsequently, we compare these models with a neural networks (BPN)-supported neural network model. Subsequently, we compare these models with a neural network model alone and, in addition, determine which of three classifiers (MDA, CBR and BPN) can perform better. This article is then to examine the predictability of integrated neural network models for interest rate forecasting using change-point detection.

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