• 제목/요약/키워드: Expansion Process

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CBP 시장 체제하에서의 전력수급계획 수립 체계에 관한 연구 (A Study on the Generation Expansion Planning System Under the Cost Based Pool)

  • 한석만;김발호
    • 전기학회논문지
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    • 제58권5호
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    • pp.918-922
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    • 2009
  • The power expansion planning is large and capital intensive capacity planning. In the past, the expansion planning was established with the proper supply reliability in order to minimize social cost. However, the planning cannot use cost minimizing objective function in the power markets with many market participants. This paper proposed the power expansion planning process in the power markets. This system is composed of Regulator and GENCO's model. Regulator model used multi-criteria decision making rule. GENCO model is very complex problem. Thus, this system transacted the part by several scenario assuming GENCO model.

고속철도 교량 신축이음장치의 내구성 실험

  • 김병석;곽종원;신호상;김영진;박성용;장익순
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 1998년도 추계학술대회 논문집
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    • pp.24-29
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    • 1998
  • To absorb the deformation of ,external live load, thermal gradient, shrinkage and creep in bridge structures and general structures, expansion joint has to be established. Especially expansion joint for high-speed railway bridge has to accomodate the static and dynamic forces and it not only has the durability of itself but also maintain the durability of structure by preventing the leakage of water. The actual used product of expansion joint for high-speed railway bridge is only ones made in France, Germany and Japan. In this study, the development process and test results of developed expansion joint are introduced which has the functional operation and durability enough to apply to high-speed railway bridges, roadway bridges and general structures. The tests consist of fatigue-durability test of 3 million times by high-speed rail load, leakage test and jack-up test for verifying the possibility of exchanging it. The performance of developed expansion joint satisfy the specification of Korea High Speed Rail Construction Authority.

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A Brief Survey into the Field of Automatic Image Dataset Generation through Web Scraping and Query Expansion

  • Bart Dikmans;Dongwann Kang
    • Journal of Information Processing Systems
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    • 제19권5호
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    • pp.602-613
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    • 2023
  • High-quality image datasets are in high demand for various applications. With many online sources providing manually collected datasets, a persisting challenge is to fully automate the dataset collection process. In this study, we surveyed an automatic image dataset generation field through analyzing a collection of existing studies. Moreover, we examined fields that are closely related to automated dataset generation, such as query expansion, web scraping, and dataset quality. We assess how both noise and regional search engine differences can be addressed using an automated search query expansion focused on hypernyms, allowing for user-specific manual query expansion. Combining these aspects provides an outline of how a modern web scraping application can produce large-scale image datasets.

연속주조용 탄소강에서 상변화에 따른 열팽창 및 수축 거동 (Thermal Expansion and Contraction Characteristics of Continuous Casting Carbon Steels)

  • 김현철;이재현;권오덕;임창희
    • 한국재료학회지
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    • 제13권3호
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    • pp.137-143
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    • 2003
  • The air gap between the metal and mold, formed by shrinkage during solidification, causes surface and subsurface cracks in the continuous casting process. Molten crack on the surface might also occur due to improper heat transfer between them. In order to compensate the air gap in mold design, the thermal contraction is an essential factor. In this study, the thermal contraction and expansion behaviors were examined from the ($\alpha$ and pearlite)/${\gamma}$ to ${\gamma}$/$\delta$ transformations in continuous casting steels by the commercial dilatometer and the self- assembled dilatometer with laser distance measurement. It was found that the thermal contraction and expansion behaviors were very dependant on the phase transformation of the ${\gamma}$/$\delta$ as well as ($\alpha$ and pearlite)/${\gamma}$. The sudden volume change from $\delta$ to ${\gamma}$ which might cause cracks in the continuous casting process, was observed on cooling just below the melting temperature by the self-assembled dilatometer.

장대교량 신축부에서 침목간격 확대가 차량의 주행안전성 및 궤도의 구조안정성에 미치는 영향 (Effects of Expansion of Sleeper Span at the Deck End of a Long Continuous Bridge on Train Safety and Track Stability)

  • 양신추
    • 한국소음진동공학회논문집
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    • 제25권9호
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    • pp.620-627
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    • 2015
  • Long continuous bridge deck can become contracted considerably as temperature drops, which can lead to a large expansion of sleeper span at the end of it. Since this huge sleeper span then can cause problems both with safety of train operation and structural stability of tracks, it is necessary to take the issue into consideration systematically in the designing process of the bridge. In this paper, an evaluation process through the analysis of train-track interaction was presented which can basically review the effects of the expansion of sleeper span at the end of long continuous bridge deck on the safety of the train and the structural stability of the track. The analyses of the interaction between the light rail train and tracks were carried out targeting the sleeper span as a main parameter. The safety of train operation and structural stability of tracks in a light rail system due to the expansion of the sleeper span were evaluated by comparing the numerical results with the related criteria.

확관을 고려한 불균일 내면가공관의 전열특성 (Heat Transfer Characteristics of the Non-Uniform Grooved Tube Considering Tube Expansion)

  • 이상무;박병덕
    • 설비공학논문집
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    • 제24권7호
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    • pp.553-559
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    • 2012
  • A plate-fin heat exchanger is a type of heat exchanger widely used in air conditioners, and tubes and fins are tightly assembled by the mechanical expansion process of tubes. The tube expansion process deforms the grooves inside the tube, and the groove shapes also affect the adhesion between tubes and fins. In this study, the adhesion and heat transfer performance affected by the tube expansion of the non-uniform groove shape tube with different heights are investigated by both analysis and experiments. From the analysis method, it was shown that the contact pressure of non-uniform groove tube is higher than that of the uniform groove tube, and the most appropriate high groove number of the non-uniform groove tube is designed for the maximum contact pressure. From the experimental results, the decreasing rate of the condensation heat transfer coefficient is smaller in the non-uniform groove tube with different heights, compared to the conventional uniform groove tube. Also, the air-side heat transfer coefficient of the non-uniform groove tube with different heights is higher than that of the uniform groove tubes.

누적영향평가 측면에서 환경영향평가제도의 문제점과 개선방안 연구 - 석회석광산 채굴규모 확장을 대상으로 - (A Study on Environmental Impact Assessment on the Area Expansion of Limestone Mining with regard to Cumulative Impact Assessment)

  • 김초;연익준;정주용;이상우
    • 환경영향평가
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    • 제23권1호
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    • pp.1-9
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    • 2014
  • This study, focusing on the area expansion of limestone mines, identifies the problems of Environmental Impact Assessment(EIA) and what impact the current problems exert on another mines developing process. The legal relations analysis reveals that the Management of Mountainous Districts Act and other related laws effect on EIA process, especially the case of area expansion of limestone mines excluded from EIA. However, these problems can create mismatch with the policy goal of EIA system and have a negative impact on the environment in the future. A series of indepth interviews with managers in related agencies found that those agencies have been unaware of the seriousness of the problem. Without any strategy, negative result made by development activities would get more serious and sustainable development may not be possible at all. In order to solve these problems, government should modify the current interdependent legal provision and create the incentive structure to participate actively related agency in the EIA system.

밀워키미술관 신·증축에서 나타나는 공간적 특성과 쟁점 (Spatial Features and Issues in the Process of Establishing and Expanding the Milwaukee Art Museum)

  • 이승엽;변나향
    • 대한건축학회논문집:계획계
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    • 제35권1호
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    • pp.107-115
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    • 2019
  • This research explores a historical trajectory of the Milwaukee Art Museum from its establishment to the third expansion over the last six decades. After established in 1957 by the architect, Eero Saarinen, this museum underwent three expansions led by three different architects including, David Kahler, Santiago Calatrava, and James Shields. Reasons for expanding the museum were varied. A lack of exhibition space, an absence of visual identity, and path interruption problem within urban contexts were the main factors of a series of expansion. Furthermore, this research points out that there are three issues in the process of the expansion. The first is connection issues between the downtown and the lakefront in which the museum has blocked the public flow. The second, there were controversies on the allocation of the expanded space among the main body of the decision including architects, curators, and stakeholders. The last one is relationships among architects. This is related to each architect's attitude toward the museum. Drawing on historical documents and interviews with the regional architects, I argue that the identity and values of the museum have changed over time through the expansions rather than having the invariable.

A LEARNING SYSTEM BY MODIFYING A DECISION TREE FOR CAPP

  • 이홍희
    • 대한산업공학회지
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    • 제20권3호
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    • pp.125-137
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    • 1994
  • Manufacturing environs constantly change, and any efficient software system to be used in manufacturing must be able to adapt to the varying situations. In a CAPP (Computer-Aided Process Planning) system, a learning capability is necessary for the CAPP system to do change along with the manufacturing system. Unfortunately only a few CAPP systems currently possess learning capabilities. This research aims at the development of a learning system which can increase the knowledge in a CAPP system. A part in the system is represented by frames and described interactively. The process information and process planning logic is represented using a decision tree. The knowledge expansion is carried out through an interactive expansion of the decision tree according to human advice. Algorithms for decision tree modification are developed. A path can be recommended for an unknown part of limited scope. The processes are selected according to the criterion such as minimum time or minimum cost. The decision tree, and the process planning and learning procedures are formally defined.

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Preparation of needle coke from petroleum by-products

  • Halim, Humala Paulus;Im, Ji Sun;Lee, Chul Wee
    • Carbon letters
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    • 제14권3호
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    • pp.152-161
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    • 2013
  • Needle coke is an important material for graphite electrodes. Delayed coking is used to produce needle coke. Producing good quality needle coke is not simple because it is a multi-parameter controlled process. Apart from that, it is important to understand the mechanism responsible for the delayed coking process, which involves mesophase formation and uniaxial rearrangement. Temperature and pressure need to be optimized for the different substances in every feedstock. Saturate hydrocarbon, aromatic, resin and asphaltene compounds are the main components in the delayed coking process for a low Coefficient Thermal Expansion value. In addition, heteroatoms, such as sulphur, oxygen, nitrogen and metal impurities, must be considered for a better graphitization process that prevents the puffing effect and produces better mesophase formation.