• 한국수학사학회지
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• 제30권3호
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• pp.137-162
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• 2017

The Chinese algebraic method, the tian yuan shu, was developed during Song period (960-1279), of which Li Ye's works contain the earliest testimony. Two 18th century editors commentated on his works: the editor of the Siku quanshu and Li Rui, the latter responding to the former. Korean scholar Nam Byeong-gil added another response in 1855. Differences can be found in the way these commentators considered mathematical objects and procedures. The conflicting nature of these commentaries shows that the same object, the quadratic equation, can beget different interpretations, either a procedure or an assertion of equality. Textual elements in this paper help modern readers reconstruct different authors' understandings and reconsider the evolution of the definition of the object we now call 'equation'.

• International Journal of Aeronautical and Space Sciences
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• 제16권4호
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• pp.624-635
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• 2015

Design space exploration has been much neglected in aircraft conceptual design phase, which often leads to a waste of time and cost in design, manufacture and operation process. It is necessary to explore design space based on operational system-of-systems (SoS) simulation during the early phase for a competitive design. This paper proposes a methodology to analyze aircraft performance parameters in four steps: combination of parameters, object analysis, operational simulation, and key-parameters analysis. Meanwhile, the design space of an unmanned aerial vehicle applied in earthquake search and rescue SoS is explored based on this methodology. The results show that applying SoS simulation into design phase has important reference value for designers on aircraft conceptual design.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권12호
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• pp.6063-6079
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• 2019

When the length of sampling data sequence is too large, the method of gesture recognition based on traditional Dynamic Time Warping (DTW) algorithm will lead to too long calculation time, and the accuracy of recognition result is not high.Support vector machine (SVM) has some shortcomings in precision, Edit Distance on Real Sequences(EDR) algorithm does not guarantee that noise suppression will not suppress effective data.A new method based on Improved Interpolation Dynamic Time Warping (IIDTW)algorithm is proposed to improve the efficiency of gesture recognition and the accuracy of gesture recognition. The results show that the computational efficiency of IIDTW algorithm is more than twice that of SVM-DTW algorithm, the error acceptance rate is FAR reduced by 0.01%, and the error rejection rate FRR is reduced by 0.5%.Gesture recognition based on IIDTW algorithm can achieve better recognition status. If it is applied to unlock mobile phone, it is expected to become a new generation of unlock mode.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.451-456
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• 2005

The mathematical model for the heat exchangers of absorber and desorber is made in the elementary control volume method and the thermodynamic properties of working fluid. water/ammonia mixture. are calculated by some fundamental subroutines in RefProp 7.0 and flash subroutines made by authors The simulation results show that two-stage cycle has higher COP than single stage if temperature lift is high: the performance of single stage compression cycle can be improved by increase of absorber pressure. but the performance of two-stage compression cycle can not be improved in this way : the compressor discharging temperature of two-stage compression is much lower than that of single stage cycle. which is very important to the safety operation of CA heat pump. Major parameter comparison between the cycles at their optimal configurations is also given.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.548-551
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• 2009

The report of the intergovernment panel on climate change(IPCC) concluded that the global warning due to Green-house Gas(GHGs) will be accelerated in the 21th century. The railroad construction sector consumes a great deal of natural resources and energy in construction. maintenance, and demolition stage. In order to establish and perform reducing plan of GHGs of railway track system for effective corresponding the Climate Change Agreement, the evaluation method of the lifecycle CO2 emission if needed. In this research, it was investigates that the research trend for the LCCO2 and the method to estimate the lifecycle carbon dioxide emission amount of the railway track system as quantitative.

• Bulletin of the Korean Chemical Society
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• 제29권5호
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• pp.979-984
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• 2008

In this study, 8 solutes (aniline, caffeine, p-cresol, ethyl benzene, methylparaben, phenol, pyridine, and toluene) have been tested in terms of linear solvation energy relationships (LSER). Several micellar liquid chromatography (MLC) systems using cationic surfactant cetyltrimethylammonium bromide (CTAB) and a mixture of water with (methanol, n-propanol, and n-butanol) modifiers were characterized using the LSER solvation parameter model. The effects of the surfactant and modifier concentration on the retention in MLC were discussed. LSER model had demonstrated high potential to predict retention factors with high squared correlation coefficients ($r^2$ > 0.99). A comparison of predicted and experimental retention factors suggests that LSER formalism is able to reproduce adequately the experimental retention factors of the solutes studied in the different experimental conditions investigated. This model is a helpful tool to understand the solute-surfactant interactions and evaluate the retention characteristic of micellar liquid chromatography.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2005년도 춘계학술발표대회 개요집
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• pp.34-36
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• 2005

Copper wire bonding is an alternative interconnection technology that serves as a viable and cost saving alternative to gold wire bonding. In this paper, ultrasonic wedge bonding with $25{\mu}m$ copper wire on Au/Ni/Cu metallization of a PCB substrate was performed at ambient temperature. The central composite design of experiment (DOE) approach was applied to optimize the copper wire wedge bonding process parameters. After that, pull test of the wedge bond was performed to study the bond strength and to find the optimum bonding parameters. SEM was used to observe the cross section of the wedge bond. The pull test results show good performance of the wedge bond. Additionally, DOE results gave the optimized parameter for both the first bond and the second bond. Cross section analysis shows a continuous interconnection between the copper wire and Au/Ni/Cu metallization. The diffusion of Cu into the Au layer was also observed.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1119-1120
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• 2006

High Energy Milling (HEM) is applied for the grinding of cement and this can lead to substantial refinement $(<2{\mu}m)$ and mechanically activation of the powder particles. The present paper reviews the preliminary studies, explains the novel technique and suggests the route into commercial application. Particular attention is paid to wear results with an applied $Si_3N_4-grinding$ unit where no substantial wear was found after 4000 h of operation.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.937-938
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• 2006

Tungsten heavy alloys with different ratios of Mo and Ni-Fe matrix were liquid-phase-sintered to investigate their microstructural evolution. Results indicated that increased Mo in the alloy promoted the formation of a (W,Mo)(Ni,Fe) type intermetallic compound in the furnace-cooled condition. It was a monoeutectic reaction when the added Mo content was higher than 49at.%, or a eutectic reaction when this value was between 37at,% to 49at.%. When Mo was added between 25at.% to 37at.%, the precipitation of the intermetallic compound took place by either a eutectoid or peritectoid reaction.

• Journal of Information Processing Systems
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• 제15권6호
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• pp.1265-1276
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• 2019

Data deduplication is a common method to improve cloud storage efficiency and save network communication bandwidth, but it also brings a series of problems such as privacy disclosure and dictionary attacks. This paper proposes a secure deduplication scheme for cloud storage based on Bloom filter, and dynamically extends the standard Bloom filter. A public dynamic Bloom filter array (PDBFA) is constructed, which improves the efficiency of ownership proof, realizes the fast detection of duplicate data blocks and reduces the false positive rate of the system. In addition, in the process of file encryption and upload, the convergent key is encrypted twice, which can effectively prevent violent dictionary attacks. The experimental results show that the PDBFA scheme has the characteristics of low computational overhead and low false positive rate.