• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.2 s.54
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• pp.57-68
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• 2007

The mega frame system is becoming popular for the design and construction of skyscrapers because this system exhibits structural efficiency by allowing high rigidity of the structure while minimizing the amount of structural materials to be used. Since the mega frame system is usually adopted for super high-rise buildings, the comfort of occupants may be main concerns in the practical application of this system. For the enhancement of the serviceability of mega frame structures, a semi-active tuned mass damper (STMD) is developed in this study. To this end, a Magnetorheological (MR) damper is employed replacing passive damper as a semi-active damper to improve the control effect of a conventional TMD. Since a conventional finite element model of mega frame structures has significant numbers of DOFs, numerical simulation for investigation of control performances of a STMD is impossible by using the full-order model. Therefore, a reduced-order system using minimal DOFs, which can accurately represent the dynamic behavior of a mega frame structure, is proposed in this study through the matrix condensation technique To improve the efficiency of the matrix condensation technique, multi-level matrix condensation technique is proposed using the structural characteristics of mega frame structures. The efficiency and accuracy of the reduced-order control proposed in this study and the control performance of a STMD were verified using example structures.

• 한국지구물리탐사학회:학술대회논문집
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• 2004.08a
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• pp.25-48
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• 2004

Structures show the phehomena of deformation and lowering of function with time-lapse by artificial environments and changes of geotechnical conditions or accumulation of initial deformation elements. This study aims the structural assessment of cultural property, Chum-Sung-Dae, located in Kyeongju city, Korea. It was built about 1,300 years ago, and has undergone deformation and ground-subsidence with time-lapse. Non-destructive evaluation techniques were applied to the Chum-Sung-Dae, to protect it from survey Because of this reason, 3D precise laser scanning surveying system was applied to measure the exact size of Chum-Sung-Dae, displacement and declining angles. Geophysical exploration also was applied to study the subsurface distribution of geotechnical parameters or physical properties. Natural frequencies were measured from real and model of Chum-Sung-Dae to study the dynamic characteristics of vibration and/or earthquake load and stiffness of structures.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.93-93
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• 2017

To develop rice cultivars with increased biomass and grain yield, superior lodging resistance is an essential trait. The new breeding approach can be adopted for the improvement of stem lodging resistance by enhancing culm strength. The resistance to breaking type lodging is attributed to bending moment of basal culm (M), which is composed of the section modulus (SM) and bending stress (BS). The resistance to the bending type lodging is attributed to flexural rigidity (FR) of stem, which is composed of the secondary moment of inertia (SMI) and Young's modulus (YM). Starch and cell wall components such as cellulose, hemicellulose and lignin also play a significant role in physical strength of culm, and thus affect lodging. Leaf Star has a superior lodging resistance due to its thick and stiff culm because of its high M and FR compared with Koshihikari. Furthermore, Leaf Star contains high densities of hemicellulose, cellulose and low lignin density in culm compared with Koshihikari. In this study, we performed QTL analysis for these traits associated with culm strength, using 94 recombinant inbred lines (RILs, $F_8$), derived from a cross between Leaf Star and Koshihikari. The SM in the RILs showed a continuous distribution. QTLs for SM were detected on chrs.2, 3 and 10. Leaf Star alleles increased SM on chrs. 2 and 3, but Koshihikari allele increased on chr.10. These QTLs overlapped with those QTLs identified using backcrossed inbred line derived from a cross between Chugoku 117 and Koshihikari, the parents of Leaf Star. The FR in Leaf Star was higher than that in Koshihikari due to the larger SMI and YM. 3 QTLs for SMI were detected on chrs.2, 3 and 10. Leaf Star alleles increased SMI on chrs.2 and 3, and Koshihikari alleles increased on chr.10. One QTL on chr.3 and two QTLs on chr.5 for hollocelulose content were detected with Leaf Star alleles contribution. Moreover, two QTLs were detected for hemicellulose density on chrs.3 and 5. Leaf Star allele increased hemicellulose density on chr.5, and Koshihikari allele increased on chr.3. Furthermore, two QTLs for cellulose density were detected on chr.5, and one QTL on chr.2. For starch content, one QTL on chr.3 and two QTLs on chr.5 with Leaf Star alleles contribution were detected. TULK-6 carrying a chromosome segment of Leaf Star on chr.5 in the Koshihikari genetic background showed higher densities of starch and hemicellulose than those in Koshihikari. These results suggest that the detected QTLs for culm strength could be utilized for the improvement of lodging resistance in rice by marker-assisted selection.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.133-133
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• 2017

Lodging is one of the important constraints in rice production. The lodging destroys the canopy structure, and sharply reduces the capacity of photosynthetic rate and dry matter production. In cereal crops, stem lodging can be classified into two types: stem breaking type and stem bending type. To improve stem lodging resistance, it is important to reveal strong culm traits of superior lodging resistant varieties. There are large varietal differences in parameters associated with the bending moment at breaking (M) and flexural rigidity (FR). The indica variety Takanari possesses large M due to its large section modulus (SM) despite of its small bending stress (BS), while Takanari also has large FR due to its large secondary moment of inertia (SMI) and Young's modulus (YM). To identify quantitative trait loci (QTLs) and the corresponding genes associated with the parameters for M ($=SM{\times}BS$) and FR ($=SM{\times}YM$) should enable to develop lodging resistant varieties, efficiently. In order to identify QTLs for cell wall materials such as cellulose, hemicellulose and lignin associated with BS and YM, a set of Chromosome Segment of Substitution Lines (CSSLs) consisted of 37 lines with chromosome segments of Koshihikari in the genetic background of Takanari were used. Takanari had large M and small BS as compared with Koshihikari. The QTLs for BS were estimated on chromosomes 3, 5, 6, 8, 9, 10, 11 and 12. Koshihikari alleles increased BS in these QTLs. Takanari had a large FR due to its large SMI and YM as compared with Koshihikari. The YM was increased by substitution of the Koshihikari chromosomal segments on chromosomes 2, 10 and 11. Other QTLs estimated on chromosomes 7 and 12 that Koshihikari alleles contributed to the decrease of YM. For lignin, only one major QTL for lignin density was detected on chromosome 11. Hollocellulose densities were increased by the substitution of Koshihikari segments on chromosomes 5 and 11. On the other hand, these were decreased on chromosomes 1 and 3 by substitution of Koshihikari segments. QTLs for cellulose density were estimated on chromosomes 1, 3 and 5 by substitution of Koshihikari segments. For hemicellulose, QTL on chromosome 3 showed that hemicellulose density decreased by the substitution of Koshihikari segment. However, hemicellulose densities on chromosomes 5, 8 and 11 showed the opposite effects. The QTLs for hemicellulose, cellulose, and hollocelulose densities identified on chromosome 5 overlapped with that for bending stress, indicating the positive effect of Koshihikari segment on increasing bending stress. These results suggest that some QTLs for the densities of cell wall materials contribute to increasing bending stress and Young's modulus, and could be utilized to improve the lodging resistance for both types of breaking and bending in rice varieties.

• Design & Manufacturing
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• v.14 no.1
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• pp.1-7
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• 2020

In this study, the variation of the shrinkage in the thickness direction of the molded parts according to the gate size of the polymer core fabricated through the 3D printer using the SLS method was studied. The polymer cores are laser sintered and the powder material is nylon base PA2200. The polymer cores have lower heat transfer rate and rigidity than the metal core due to the characteristics of the material. Therefore, the injection molding test conditions are set to minimize the deformation of the core during the injection process. The resin used in the injection molding test is a PP material. The packing condition was set to 80, 90 and 100% of the maximum injection pressure for each gate size. The runner diameter used was ∅3mm, and the gates were fabricated in semicircle shapes with cross sections 1, 2, and 3 ㎟, respectively. Thickness measurement was performed for 10 points at 2.5 mm intervals from the point 2.5 mm away from the gate, and the shrinkage to thickness was measured for each point. The shrinkage rate according to the gate size tends to decrease as the cross-sectional area decreases as the maximum injection pressure increases. The average thickness shrinkage rate was close to 0% when the packing pressure was 90% for the gate area of 1mm2. When the holding pressure was set to 100%, the shrinkage was found to decrease by 3% from the standard dimension due to the over-packing phenomenon. Therefore, the smaller the gate, the more closely the molded dimensions can be molded due to the high pressure generation. It was confirmed that precise packing process control is necessary because over-packing phenomenon may occur.

• Science of Emotion and Sensibility
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• v.10 no.1
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• pp.99-111
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• 2007

In order to identify tactile sensibility factors of traditional silk fabrics and to provide prediction models for the sensibility factors by mechanical properties, seventeen different traditional silk fabrics were evaluated in terms of both tactile sensation and sensibility by using a modified magnitude estimation line scale Gongdan and Newttong with lower values for surface roughness(SMD), bending rigidity(B), and compression resilience(RC) were rated as softer, smoother, fluffier, and more pliable in tactile sensation than any other traditional silk fabrics whereas Nobangju haying higher B, SMD, and tensile resilience(RT) was touched as crisper, more rustling, and springier. Three different tactile sensibility factors including 'Feminine', 'Natural', and 'Casual' were obtained significantly by grouping fifteen different tactile sensibility descriptors. In the prediction models sensibility 'Feminine' was explained positively by SMD, which was supported by the fact that both Gongdan and Newtton were perceived as more feminine. Sensibility 'Natural' that was felt stronger as for Myoungju and Sa was predicted negatively by both fabric thickness(T) and RT. Finally, RC, elongation at maximum load (EM), and T predicted sensibility 'Casual' negatively, which results in its higher factor scores for Myoungju and Shantung, respectively.

• Science of Emotion and Sensibility
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• v.18 no.3
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• pp.17-24
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• 2015

This study investigated heat generation characteristics of knitted and woven intelligent garments made of ZrC imbedded yarns through thermal manikin measurement. These emotional and intelligent thermal characteristics by thermal manikin measurement were analysed and compared with light/thermal radiation experimental results. Surface temperature of ZrC imbedded woven and knitted fabrics by light/thermal radiation measurement was $4^{\circ}C$ and $2^{\circ}C$ higher than that of regular PET control fabrics, respectively. Clo value as heat generation characteristics of ZrC imbedded woven and knitted garments with light exposure was 0.14 and 0.08 higher than that of regular PET control garments, respectively. These results were attributed to the far-infrared thermal radiation from ZrC imbedded in the core part of the intelligent bi-component filament, which was verified by far-infrared emissive power ranged between $6{\mu}m$ and $20{\mu}m$ through FT-IR experiment and by inclusion of Zr through EDS ingredient analysis. However, compressibility of ZrC imbedded woven fabric was lower than that of regular PET one, and bending rigidity was higher than that of regular one, which resulted in a little stiff tactile hand property of ZrC imbedded fabric. We found that ZrC imbedded intelligent woven and knitted fabrics were applicable to the intelligent garment as a heat generation textile material by thermal manikin measurement.

• Journal of Korean Society of Steel Construction
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• v.23 no.5
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• pp.535-546
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• 2011

In this paper, semi-rigid elasto-plastic post-buckling analysis of a space frame was performed using various explicit arc-length methods. Various explicit arc-length methodsand a large-deformation and small-strain elasto-plastic 3D space frame element with semi-rigid connections and plastic hinges were developed. This element can be appliedto both explicit and implicit numerical algorithms. In this study, the Dynamic Relaxation method was adopted in the predictor and corrector processesto formulate an explicit arc-length algorithm. The developed "explicit-predictor" or "explicit-corrector" were used in the elasto-plastic post-buckling analysis. The Eulerian equations for a beam-column with finite rotation, which considers the bowing effects, were adopted for the elastic system and extended to theinelastic system with a plastic hinge concept. The derived tangent stiffness matrix was asymmetrical due to the finite rotation. The joint connection elements were introduced for semi-rigidity using a static condensation technique. Semi-rigid elasto-plastic post-buckling analyses were carried out to demonstrate the potential of the developed explicit arc-length method and advanced space frame element in terms of accuracy and efficiency.

• Journal of Science and Technology Studies
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• v.18 no.1
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• pp.219-265
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• 2018

Recently, interest in energy tranisition is rising. Energy transition requires active participation and cooperation of diverse stakeholders, including users / citizens, in that it requires not only changes in technological factors but also changes and coordination of various social factors. Living labs are attracting attention as one of the ways to do this. This article is a detailed analysis of the activities of the mini-PV living lab in the urban area from 2016 to 2017 at the Seoul, Sung Dae Goal. Through the Living Lab, mini PV DIY products, backup centers, local financial services, and the development of a variety of education and training strategies have been achieved. These activities and achievements were analyzed through questions raised on strategic, tactical, and operational levels, as well as through multi-level perspective and interaction between initiative, regime, and niche. In conclusion, this living lab activity confirmed the possibility of a 'transition lap' to solve social problems such as sustainability of energy production and utilization. In particular, it gained remarkable results in terms of the operational leves of transition management governance, that is, transition experiment, and it was also remarkable in that it was the initiative of citizens. However, it did not proceed without difficulty. In particular, structural problems such as the conflict between the flexibility inherent in living lab and the bureaucratic rigidity of the financial support organization have appeared. There was also a limitation that there was no 'transition field' on the strategic level necessary to replicate and expand strategic niches while spreading the knowledge gained from the transition experiment, forming the vision of transition.

• Journal of Korean Home Economics Education Association
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• v.23 no.1
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• pp.37-51
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• 2011

The purpose of this study was to examine the effects of temperament, family strength and social support on ego-resilience of adolescents. Four hundred fifty middle and high school students in Incheon participated. Temperament, family strength, social support and ego-resilience were evaluated by self-report questionnaires. Data were analyzed using factor analyses, t-tests, descriptive statistics, correlations and standard multiple regression analyses. Results indicated that there was significant gender difference in ego-resilience. Adolescents' ego-resilience was positively associated with activity level and persistence in temperament, family strength and social support, but negatively associated with rigidity in temperament. Furthermore, gender, temperament, family strength and social support of class teacher and close friends significantly predicted ego-resilience of adolescents.