• Title/Summary/Keyword: Reduction methods

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Analysis of Greenhouse Gas Reduction Potentials in a University using Bottom-up Model (상향식 모형을 이용한 대학의 온실가스 감축 잠재량 평가)

  • Yoo, Jung-Hwa;Park, Nyun-Bae;Jo, Mi-hyun;Jeon, Eui-Chan
    • Journal of Climate Change Research
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    • v.3 no.3
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    • pp.183-193
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    • 2012
  • In this study, the S University's energy usage, greenhouse gas emissions situation and potential reduction amount were analyzed using a long-term energy analysis model, LEAP. In accordance with the VISION 2020 and university's own improvement plans, S University plans to complete a second campus through expansion constructions by 2020 and by allocating the needed land. Accordingly, increases in energy usage and greenhouse gas emissions seem inevitable. Hence, in this study, the calculations of potential reduction amount by 2020 were attempted through the use of LEAP model by categorizing the energy used based on usage types and by proposing usage typebased reduction methods. There were a total of 4 scenarios: a standard scenario that predicted the energy usage without any additional energy reduction activity; energy reduction scenario using LED light replacement; energy reduction scenario using high efficiency building equipment; and a scenario that combines these two energy reduction scenarios. As scenario-based results, it was ascertained that, through the scenario that had two other energy reduction scenarios combined, the 2020 greenhouse gas emissions amount would be 14,916 tons of $CO_2eq$, an increase of 43.7% compared to the 2010 greenhouse gas emissions amount. Put differently, it was possible to derive a result of about 23.7% reduction of the greenhouse gas emissions amount for S University's greenhouse gas emissions amount through energy reduction activities. In terms of energy reduction methods, changing into ultra-high efficiency building equipment would deliver the most amount of reduction.

State-of-practice and State-of-Art for the Project Cycle Time Reduction

  • Hong, Tae Hoon
    • Architectural research
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    • v.7 no.2
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    • pp.69-79
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    • 2005
  • There are no formal decision tools or guidelines to assist owners and contractors in choosing delivery systems and project strategies that would allow for a radical reduction in project cycle time - from the preplanning phase through project start up. Therefore, it is important to identify the state-of-practice and the state-of-art on methods of achieving radical reduction defined as a reduction of 25% or more in overall project cycle time. A comprehensive literature review, three questionnaire surveys, and the seven case studies were conducted and the data obtained from them were analyzed to establish the state-of-practice and state-of-art for project cycle time reduction techniques.

A Model Reduction Method for Effective Analysis of Structures (구조물의 효율적인 해석을 위한 모델 축소기법 연구)

  • Park, Young-Chang;Hwang, Jai-Hyuk
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.14 no.1
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    • pp.28-35
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    • 2006
  • Substructure coupling or component mode synthesis may be employed in the solution of dynamic problems for large, flexible structures. The model is partitioned into several subdomains, and a generalized Craig-Bampton representation is derived. In this paper the mode sets (normal modes, constraint modes) is employed for model reduction. A generalized model reduction procedure is described. Vaious reduction methods that use constraint modes is described in detail. As examples, a flexible structure and a 10 DOF damped system are analyzed. Comparison with a conventional reduction method based on a complete model is made via eigenpair and dynamic responses.

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Tutorial: Methodologies for sufficient dimension reduction in regression

  • Yoo, Jae Keun
    • Communications for Statistical Applications and Methods
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    • v.23 no.2
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    • pp.105-117
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    • 2016
  • In the paper, as a sequence of the first tutorial, we discuss sufficient dimension reduction methodologies used to estimate central subspace (sliced inverse regression, sliced average variance estimation), central mean subspace (ordinary least square, principal Hessian direction, iterative Hessian transformation), and central $k^{th}$-moment subspace (covariance method). Large-sample tests to determine the structural dimensions of the three target subspaces are well derived in most of the methodologies; however, a permutation test (which does not require large-sample distributions) is introduced. The test can be applied to the methodologies discussed in the paper. Theoretical relationships among the sufficient dimension reduction methodologies are also investigated and real data analysis is presented for illustration purposes. A seeded dimension reduction approach is then introduced for the methodologies to apply to large p small n regressions.

MPV-Reduction of C=O bond with Al-substituted-dialkylalan; A Theoretical Study on Relative Reactivity of Various Carbonyl Substrates

  • Nahm, Keepyung
    • Bulletin of the Korean Chemical Society
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    • v.35 no.2
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    • pp.546-550
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    • 2014
  • Relative reactivity of various carbonyl and acid derivatives in MPV-type (Meerwein-Ponndorf-Verley) reduction with an DIBAL(F) model has been studied via DFT and MP2 methods. Free energies of initial adduct formation (-Gadd) of DIBAL(F) model and carbonyls are in the order of amide < ester < aldehyde < ketone < acid chloride; in the alan-amide adduct, the developed positive charge at carbonyl carbon is expected to be stabilized by amide resonance, but in the acid chloride adduct it is destabilized by inductive effect of chloride. However the TS barrier energies (${\Delta}G_{TS}$) for the MPV-type hydride reduction of the carbonyl adducts are in the order of aldehyde < ketone < acid chloride << ester < amide; presumably decreasing order of electrophilicity of carbonyl carbon at adducts, which is well correlated with experimental data. It is noted that the relative reactivity of carbonyl derivatives in MPV-type reduction with DIBAL(X) is not governed by the alan-adduct formation energies, but follows the order of electrophilicity of carbonyl carbon of transition states.

Measuring and evaluation of reduction gear unit for running test of Korea High Speed Train (한국형 고속전철용 감속구동장치 시운전 시험 및 평가)

  • Lee Dong-Hyong;Seo Jung-Won;Moon Kyoung-Ho;Choi Kyung-Jin;Choi Kang-Youn
    • Proceedings of the KSR Conference
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    • 2003.05a
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    • pp.554-560
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    • 2003
  • The transmission systems of high speed train serve in the severe condition compared with those of other trains, namely, they have to transmit high power to run with high speed and they have to make maximum use of the limited space. To clarify the capability of reduction gear unit for Korea High Speed Train, torque and temperature, vibration on the reduction gear unit were measured and test data were analyzed. This paper reports test methods and test results that performed to verify reliability of reduction gear unit during running test of Korea High Speed Train. It is confirmed from these results that the performance of reduction gear unit has not any problem.

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Performance test for transmitted noise reduction of smart panel using piezoelectric shunt damping (압전 션트를 이용한 패널의 투과소음 저감 성능에 관한 연구)

  • 최진영;김재환;이중근
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11b
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    • pp.1120-1125
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    • 2001
  • A new concept of piezoelectric smart panels for noise reduction in wide band frequencies is proposed and their possibility is experimentally investigated. Multi-mode damping is studied by using a newly proposed tuning method. The proposed panels are based on passive shunt damping methods. This method is based on electrical impedance model and maximizing the dissipated energy at the shunt circuit. four PZT are attached on smart panel for improving performance of transmission noise reduction. 0 prove the concept of piezoelectric smart panels, an acoustic measurement experiment was performed. The smart panels exhibit a good noise reduction in middle and high frequency ranges due to the mass effects of absorbing materials or/and the air gap. The use of piezoelectric smart panel renders noise reduction at resonance frequency. Noise reduction at multiple resonance frequencies is experimentally investigaed.

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A Study on Model Reduction for Effective Analysis of Structure (구조물의 효율적인 해석을 위한 모델 축소기법 연구)

  • 박영창;황재혁;오화석
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11b
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    • pp.1370-1375
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    • 2001
  • Substructure coupling or component mode synthesis may be employed in the solution of dynamic problems for structure. The model is partitioned into several subdomains. and a generalized Craig-Bampton representation is derived. In this paper the mode sets(normal modes. constraint modes) have been employed for model reduction. A generalized model reduction procedure has been described. Those reduction methods which adapt constraint modes have been described in detail. As examples. a flexible structure and a 10 DOF damped system are analyzed. Comparison with a conventional reduction method based on a complete model has been made via eigenpairs and dynamic responses.

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Stoichiometry, Thermal Stability and Reducibility of Perovskite-Type Mixed Oxide LaBO$_3$ (B = Fe, Co, Ni)

  • Park, Il-Hyun;Lee, Hyung-Pyo
    • Bulletin of the Korean Chemical Society
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    • v.9 no.5
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    • pp.283-288
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    • 1988
  • The titled properties on reduction of the perovskite $LaBO_3$ (B = Fe, Co, Ni) have been investigated by means of temperature-programmed reduction, isothermal reduction and X-ray diffraction methods. Nominal composition of $LaFeO_{3.18},\;LaCoO_{3.00}\;and\;LaNiO_{2.92}$ are determined. Reduction reaction of these mixed oxides differed according to B-site transition metal and thermal stability on reduction decreased as following order: $LaFeO_{3.18}$ > $LaCoO_{3.00}$ > $LaNiO_{2.92}$. From the results of isothermal reaction, kinetics on reduction of the perovskite has been discussed in detail.

Comparison of Methods for Reducing the Dimension of Compositional Data with Zero Values

  • Song, Taeg-Youn;Choi, Byung-Jin
    • Communications for Statistical Applications and Methods
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    • v.19 no.4
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    • pp.559-569
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    • 2012
  • Compositional data consist of compositions that are non-negative vectors of proportions with the unit-sum constraint. In disciplines such as petrology and archaeometry, it is fundamental to statistically analyze this type of data. Aitchison (1983) introduced a log-contrast principal component analysis that involves logratio transformed data, as a dimension-reduction technique to understand and interpret the structure of compositional data. However, the analysis is not usable when zero values are present in the data. In this paper, we introduce 4 possible methods to reduce the dimension of compositional data with zero values. Two real data sets are analyzed using the methods and the obtained results are compared.