• Title/Summary/Keyword: Structural Changes

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A qualitative study of photomemory characteristics of the LB monolayer films of merocyanine dye (메로시아닌 색소 LB 단분자막의 광메모리 특성에 관한 정성적 연구)

  • 박태곤;권영수;강도열
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.44 no.7
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    • pp.889-894
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    • 1995
  • The structural changes of the merocyanine monolayer LB (Langmuir Blodgett) films were investigated. These changes were compared with the typical changes of the molecular structures of merocyanine solutions. The structural changes of quinoid/benzenoid were attained by exposure to atmosphere gases (HCl gas, N $H_{3}$ gas). The photoisomerization was not observed for the monolayer LB film due to their state of $M_{trans}$. But we could obtain the cis/trans photoisomerization characteristics reversibly, after the films were changed to M $H^{+}$$_{trans}$ structure by exposure to HCl gas. We also found that the cis/trans photoisomerization of the LB monolayer films show the memory characteristics.s.

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Effect of Input Data Video Interval and Input Data Image Similarity on Learning Accuracy in 3D-CNN

  • Kim, Heeil;Chung, Yeongjee
    • International Journal of Internet, Broadcasting and Communication
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    • v.13 no.2
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    • pp.208-217
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    • 2021
  • 3D-CNN is one of the deep learning techniques for learning time series data. However, these three-dimensional learning can generate many parameters, requiring high performance or having a significant impact on learning speed. We will use these 3D-CNNs to learn hand gesture and find the parameters that showed the highest accuracy, and then analyze how the accuracy of 3D-CNN varies through input data changes without any structural changes in 3D-CNN. First, choose the interval of the input data. This adjusts the ratio of the stop interval to the gesture interval. Secondly, the corresponding interframe mean value is obtained by measuring and normalizing the similarity of images through interclass 2D cross correlation analysis. This experiment demonstrates that changes in input data affect learning accuracy without structural changes in 3D-CNN. In this paper, we proposed two methods for changing input data. Experimental results show that input data can affect the accuracy of the model.

Evolution of China's Economy and Monetary Policy: An Empirical Evaluation Using a TVP-VAR Model

  • Kim, Seewon
    • East Asian Economic Review
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    • v.25 no.1
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    • pp.73-97
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    • 2021
  • China has experienced many structural changes in the process of economic development over the past three decades. Using a time-varying parameter VAR model with stochastic volatility and mixture innovations, this study investigates whether such structural changes in, especially tools and operational aims of monetary policy, affect the monetary transmission mechanism. We find that impulse responses of output growth and inflation to monetary shocks have substantially increased and then reversed to decrease around 2005-2006. This time variation is mainly caused by changes in the monetary transmission mechanism, i.e., the manner in which main macroeconomic variables respond to policy shocks, rather than by changes in volatilities of exogenous shocks. The result implies that aggressive monetary policy to facilitate economic growth in the developing economies may be legitimized, unless it causes inflation seriously.

Improvement of the earthquake resistance of R/C beam-column joints under the influence of P-△ effect and axial force variations using inclined bars

  • Tsonos, Alexander G.
    • Structural Engineering and Mechanics
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    • v.18 no.4
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    • pp.389-410
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    • 2004
  • In this study, theoretical and experimental results are presented which were obtained during an investigation of the influence of the $P-{\Delta}$ effect that was caused by the simultaneous changing of the axial load P of the column and the lateral displacement ${\Delta}$ in the external beam-column joints. The increase or decrease of ${\Delta}$ was simultaneous with the increase or decrease of the axial compression load P and caused an additional influence on the aseismic mechanical properties of the joint. A total of 12 reinforced concrete exterior beam-column subassemblies were examined. A new model, which predicts the beam-column joint ultimate shear strength, was used in order to predict the seismic behaviour of beam-column joints subjected to earthquake-type loading plus variable axial load and $P-{\Delta}$ effect. Test data and analytical research demonstrated that axial load changes and $P-{\Delta}$ effect during an earthquake cause significant deterioration in the earthquake-resistance of these structural elements. It was demonstrated that inclined bars in the joint region were effective for reducing the unfavourable impact of the $P-{\Delta}$ effect and axial load changes in these structural elements.

Response Force Distribution Factors of Members and Mutuality of Response Forces between Members (부재응력분포계수와 부재간 응력 상관성)

  • 김치경;이시은;홍건호
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2004.10a
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    • pp.363-370
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    • 2004
  • This Paper presents the response force distribution factor(RDF) and its application to recalculation of member forces in case of partial changes of structures. Using RDF, the mutuality of response forces between members can be estimated. The reanalysis technique recalculates directly any displacement or member force under consideration in real time without a full reanalysis in spite of local changes in member stiffness or connectivity using RDF. It is expected that RDF and the reanalysis technique can be used to develop efficient analysis techniques for tall buildings.

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A Microscopic Study on Structural Changes in Electric Conductors Due to Electric Fire (전기화재에 의한 전선의 현미경 조직변화에 관한 물성적 해석의 연구)

  • Hyung Ju Woo
    • 전기의세계
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    • v.20 no.5
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    • pp.9-14
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    • 1971
  • This paper aims to study structural changes in electric conductors which are heated during electric fire by means of microscope. The results are applicable to the pursuit of the causes of electric fire and to the establishment of criteria for the indentification of electric fire. This work is an extension of the previous study by the author, particularly with emphasis on quantitative analysis.

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Experimental and numerical study of Persian brick masonry barrel vaults under probable structural hazards

  • Saeid Sinaei;Esmaeel Izadi Zaman Abadi;Seyed Jalil Hoseini
    • Structural Engineering and Mechanics
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    • v.87 no.4
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    • pp.317-332
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    • 2023
  • Understanding and analysing the behaviour and response of historical structures in the face of climate changes and environmental conditions is of utmost significance for their preservation. There are several structural hazards associated with climate and hydrology changes in the region, including the settlement of piers, the rotation of piers, and temperature changes. The present study investigates the experimental and numerical structural behaviour of skewed and non-skewed Persian brick masonry barrel vaults under various conditions. The external loading conditions included pier rotation in five modes, settlement, and temperature variations in four states. Initially, the experiments extracted the mechanical properties of the scaled materials. Then, three semi-circular brick barrel vaults were tested with gravitational loads. The outcomes were used to develop and validate the finite element model. Following the development of the finite element model, numerical and parametric studies were conducted on the effect of the aforementioned structural hazards on the response of brick masonry barrel vaults with various Persian geometries (semi-circular, drop pointed, and four-centred), angles of skew (0, 15, 30, and 45 degrees), and dimensional ratios. According to the findings, the fragility of masonry materials makes historical structures susceptible to failure under different loading. A brick barrel vault fails in the presence of minor rotation and settlement of the piers. The four-centred geometric shape has the lowest performance among the seven Persian geometries; therefore, its health monitoring and retrofitting should be prioritised. In Isfahan, Iran, temperature variations, particularly during the warm seasons, cause critical conditions in such structures.

Evaluation of Physicochemical Changes in Hard-Boiled Eggs Stored at Different Temperatures

  • Gamaralalage Schithra Rukshan Eregama;Shine Htet Aung;Herath Mudiyanselage Jagath Chaminda Pitawala;Mahabbat Ali;Seong-Yun Lee;Ji-Young Park;Edirisinghe Dewage Nalaka Sandun Abeyrathne;Ki-Chang Nam
    • Food Science of Animal Resources
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    • v.44 no.1
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    • pp.74-86
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    • 2024
  • Eggs that have been hard-boiled are frequently used as ready-to-eat food. Refrigerated and frozen storage of hard-boiled eggs causes issues, such as customer rejection owing to textural changes. The objective of this research is to ascertain how storage temperature affects hard-boiled eggs' alteration in texture over time. Medium-sized brown shell eggs were acquired from a local market, boiled at 100℃ for 15 min, and then stored at room temperature (25℃), refrigeration (4℃), and freezing (-18℃) conditions for 0, 12, 24, and 48 h. Fourier transform infrared spectroscopy (FTIR), texture profile, visual observation using a gemological microscope, free amino acid content, and color were measured. Freezing had a substantial impact on the eggs' hardness, gumminess, chewiness, and cohesiveness (p<0.05). The FTIR spectrums confirmed the textural changes in bonds of amide A (3,271 cm-1), amide I (1,626.2 cm-1), amide II (1,539.0 cm-1), C=O stretch of COO- (1,397 cm-1), asymmetric PO2- stretch (1,240 cm-1). Microscopic images confirmed structural changes in eggs stored at -18℃. The free amino acid content was lower in fresh and frozen eggs than in the rest (p<0.05). However, there was no discernible variation in the egg white's color when eggs were kept at 4℃ (p>0.05). Salmonella spp. was found exclusively in eggs kept at room temperature. In conclusion, hard-boiled eggs did not exhibit structural or chemical changes when stored at 4℃ for up to 48 h compared to freezing and room temperature conditions.

Parametric Design Process for Structural Quantity Optimization of Spatial Building Structures (대공간 건축물 골조물량 최적화를 위한 파라메트릭 설계 프로세스)

  • Choi, Hyunchul;Lee, Si Eun;Kim, Chee Kyeong
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.2
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    • pp.103-110
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    • 2017
  • In this paper, it is covered in detail the process of generating structural alternatives with geometry change and its optimization by StrAuto. The main roof structure of the Exhibition Center is modelled parametrically and the optimal alt is derived by observing volume changes according to geometry change of main roof truss. Existing studies performed optimization process through sections and properties due to the limitations of shape change, but this study have meaning of performing the optimization with geometry changes which is the most critical skills of StrAuto. By the process of securing a sufficient margin by geometry changes and reducing volume with the optimization of sections, despite of a partial optimization of large space structure, it could be reduced by 11.7% of the total volume.

Investigation on structural symmetry of CsCoCl3·2H2O crystals by magic-angle spinning 1H and static 133Cs nuclear magnetic resonance

  • Park, Sang Hyeon;Jang, Du Chang;Jeon, Hara;Gyeong, Oh Yi;Lim, Ae Ran
    • Journal of the Korean Magnetic Resonance Society
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    • v.26 no.1
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    • pp.10-16
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    • 2022
  • The phase transition temperatures of CsCoCl3·2H2O crystals are investigated via differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Three endothermic peaks at temperatures of 370 K (=TC1), 390 K (=TC2), and 416 K (=TC3) were observed for phase transitions from CsCoCl3·2H2O to CsCoCl3·1.5H2O, to CsCoCl3·H2O, and then to CsCoCl3·0.5H2O, respectively. In addition, the spin-lattice relaxation time T in the rotating frame and T1 in the laboratory frame as well as changes in chemical shifts for 1H and 133Cs near TC1 were found to be temperature dependent. Our analyses results indicated that the changes of chemical shifts, T, and T1 are associated with structural phase transitions near temperature TC1. The changes of chemical shifts, T, and T1 near TC1 were associated with structural phase transitions, owing to the changes in the symmetry of the structure formed of H2O and Cs+ ions. Consequently, the structural symmetry in CsCoCl3·2H2O crystals based on temperature is discussed by the environments of their H and Cs nuclei.