• Geomechanics and Engineering
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• v.15 no.2
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• pp.721-728
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• 2018

The surrounding rock mass contains cracks and joints which are distributed randomly around tunnels, and in the process of tunnel blasting excavation, radial cracks could also be induced in the surrounding rock mass. In order to clearly understand the impact of radial cracks on tunnel stability, tunnel model tests and finite element numerical analysis were implemented in this paper. Two kinds of materials: cement mortar and sandstone, were used to make tunnel models, which were loaded vertically and confined horizontally. The tunnel failure pattern was simulated by using RFPA2D code, and the Tresca stresses and the stress intensity factors were calculated by using ABAQUS code, which were applied to the analysis of tunnel model test results. The numerical results generally agree with the model test results, and the mode II stress intensity factors calculated by ABAQUS code can well explain the model test results. It can be seen that for tunnels with a radial crack emanating from three points on tunnel edge, i.e., the middle point between tunnel spandrel and its top with a dip angle $45^{\circ}$, the tunnel foot with a dip angle $127^{\circ}$, and the tunnel spandrel with $135^{\circ}$ with tunnel wall, the tunnel model strength is about a half of the regular tunnel model strength, and the corresponding tunnel stability decreases largely.

• Journal of the Korean Wood Science and Technology
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• v.14 no.2
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• pp.3-12
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• 1986

The aim of this study is to determine the flexural properties(Modulus of Rupture, Modulus of Elasticity) of Platanus occidentalis L. laminated beams fabricated with 1, 3, 5, 8, 15 lamination and Tension, Compression lamination. The results were as follows: 1. MOR increased with increasing number of lamination in 3, 5, 8, 15-beam and Tension lamination beam. MOR of Compression lamination beam was lower than that of 3-beam, MOR of vertical beam not having Tension or compression lamination was lower than that of horizontal beam, but MOR of vertical beam with tension or compression lamination was same or slightly higher than that of horizontal beam. 2. The allowable working stress showed the same tendency. This stress increased with increasing number of lamination. This value of Tension lamination beam was higher than that of compression lamination beam. 3. MOE of all laminated beams was higher than that of solid beam and Tension lamination beam was higher than that of 3-beam. MOE of Tension lamination beam was higher than that of Compression lamination beam. MOE of all vertical beam was higher than that of horizontal beam except for T-2, T-5, C-3. 4. Most beam failures appeared to begin in tension. These tension failures were classified into Splintering tension, Cross-grained tension, Simple tension, Brittle tension. All test beam failures could be classified into three categories. 1) Tension failure 2) Compression failure 3) Horizontal shear failure.

• BMB Reports
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• v.40 no.3
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• pp.349-357
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• 2007

The ubiquitous family of 14-3-3 proteins functions as regulators in a variety of physiological processes. Eight rice 14-3-3 genes, designated OsGF14a through h, were identified from an exhaustive search of the genome database. Comparisons of deduced amino acid sequences reveal a high degree of identity among members of the OsGF14 family and reported Arabidopsis 14-3-3 proteins. A phylogenetic study indicates that OsGF14s contain both $\varepsilon$ and non-$\varepsilon$ forms, which is also confirmed by a structural analysis of OsGF14 genes. Furthermore, transcripts of OsGF14b, OsGF14c, OsGF14d, OsGF14e, OsGF14f and OsGF14g were detected in rice tissues. Their different expression patterns, the different effects of environmental stresses and plant hormones on their transcription levels, and the different complementary phenotypes in yeast 14-3-3 mutants not only indicates that OsGF14s are responsive to various stress conditions and regulated by multiple signaling pathways, but also suggests that functional similarity and diversity coexist among the members of OsGF14 family.

• Journal of the Korean Wood Science and Technology
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• v.28 no.4
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• pp.61-71
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• 2000

The effect of the treatment with CCFZ, FR-4, and PEG400 from butt end on the dimensional stability and bending properties was examined. Three softwood species such as red pine, Korean white pine and Japanese larch and three hardwood species such as poplar, alder and oak were investigated in this research. Shrinkage of red pine, Korean white pine, poplar, and alder treated with PEG400 decreased. However, there was no significant decrease of shrinkage in Japanese larch and oak. The decrease of shrinkage when moisture content changed from about 20% to 10% was larger than that at any other phase. In regard to the effect of treatment on bending properties, bending MOE and MOR of all specimens treated with PEG400 decreased significantly. Especially in the case of red pine, poplar, and alder treated with PEG400, bending MOR reduced 9%, 14%, and 12%, respectively. Reductions of MOR of the hardwood was also much larger than that of the softwood. However, in all species, treatment with CCFZ and FR-4 did not affect the change of bending MOE and MOR significantly. Comparing the large specimen which also included heartwood with the small specimen which included only treated sapwood, there was a difference in the change of bending MOE and MOR between them. The large specimens of Korean white pine, alder and Poplar, which had a relatively low proportion of sapwood(18~22%), showed the decrease of MOR by 11~13% more than that of small specimens, while red pine, Japanese larch and oak, which had a relatively high proportion of sapwood(35~40%), showed little decrease. It means that bending MOE and MOR of structural wood treated from butt end should be considered in terms of sapwood proportion as well as effect of treated chemicals.

• Journal of the Korean Wood Science and Technology
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• v.43 no.1
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• pp.86-95
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• 2015

This study was performed to study physical and mechanical properties of hybrid cross laminated timber (HCLT) with plywood as core layer in order to improve its mechanical properties for wooden housing. MOE, MOR, and dimensional stability of the HCLT were determined, depending on plywood composition and lamination direction. MOR value of the HCLT was improved as much as that of the glued laminated timber, which was 59.6% stronger than that of the cross laminated timber (CLT) control group. All MOE values of the HCLT were similar to glued laminated timber structure control group regardless of plywood composition and lamination directions. The dimensional stability of the HCLT was better than those of the glued laminated timber and CLT control group, owing to the use of plywood in the core.

• Journal of the Korean Wood Science and Technology
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• v.43 no.1
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• pp.36-42
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• 2015

This study examined true modulus of elasticity (MOE) and modulus of rigidity (G) for domestic woods with different slenderness ratios (L/D) using the static bending and stress wave tests. Bending properties of small clear wood specimen of three domestic wood species were determined at 12% moisture content. The results of this study indicated that both MOR and MOE of domestic woods were affected by the slenderness ratio. As the slenderness ratio increased, MOR and MOE increased. G and true MOE of domestic timber beams were obtained at different slenderness ratios by flexure test and stress wave test. The values reported here can be useful if these species woods are used for structural purposes. However, the reported values are only indicative and do not represent the true average of wood species due to the limited number of specimens tested.

• Journal of Korea Foresty Energy
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• v.22 no.2
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• pp.60-68
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• 2003

In forest products industry, a variety of nondestructive evaluation techniques are now being used to assess the mechanical properties of structural lumber. Ultrasonic and longitudinal vibration technique are frequently used to assess the modulus of elasticity(MOE) of lumber. The objective of this research was to evaluate the MOE and modulus of rupture(MOR) of small-diameter of Larix log(Larix kaempferi Carr.), using these techniques. In this study, 50 small-diameter logs were nondestructiveively evaluated. The dynamic modulus of elasticity(Eu) of the logs was first evaluated, using an ultrasonic method. After ultrasonic tests, the logs were measured using a longitudinal vibration technique(Ev). Static bending test was then performed on the logs to obtain the static modulus of elasticity(Es) and modulus of rupture of these logs. In general, the dynamic MOE (Ev) of logs was closely co..elated with the stati, MOE for log. Based on the results of these experiments, it can be concluded that small-diameter Larix logs can be successfully evaluated by Ultrasonic and longitudinal vibration technique. The experimental results indicated that the ultrasonic technique is effective to the log, which contains many knots. The longitudinal vibration technique is effective to the log, in which many cracks are included.

• Journal of the Korean Wood Science and Technology
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• v.43 no.2
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• pp.168-176
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• 2015

This study was performed to investigate the effects of heat treatment the on mechanical properties of two species of wood under different heating conditions including at $180^{\circ}C$ for 12 h and 24 h, and at $210^{\circ}C$ for 3 h and 6 h. Two species of wood, Pinus densiflora and Larix kaempferi, were exposed to different heat treatments to assess the effects on the volume change, bending properties in static and dynamic mode and compressive strength. The results showed heat treatment caused significant changes in mechanical properties such as the static and dynamic moduli of elasticity ($MOE_d$ and $MOE_s$), and the modulus of rupture (MOR). The volume of the wood after heat treatment decreased as the heating temperature and time were increased. The bending strength performance of the wood after heat treatment decreased as the heating temperature and time were increased. The effect of heat treatment at a high temperature on the bending MOR was greater in both species than that for a long time. However, the compressive strengths of all the heat-treated samples were higher than the control sample. Furthermore, highly significant correlations between $MOE_d$ and MOR, and $MOE_s$ and MOR were found for all heating conditions.

• Journal of the Korean Wood Science and Technology
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• v.42 no.3
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• pp.275-281
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• 2014

In this study, accelerated weathering test was performed with wood, a major material for wooden cultural building. In order to evaluate the deterioration of wood, ultrasonic transmission times were measured to evaluate dynamic modulus of elasticity (MOE), which was verified by determining static MOE using three-point bending test. Ultrasonic transmission time was decreased with an increase in the weathering time levels (0, 500, 1000 hours) while it increased in 1500 and 2000 hours. Distribution of dynamic and static MOE was similar to that of the ultrasonic transmission time measurements. The results mean that the measurement of ultrasonic transmission time was very effective to evaluate MOE of wooden cultural buildings for their preservation and management. This method could be utilized to assess wooden cultural buildings as a way of preserving them in a scientific manner.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.12
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• pp.3315-3337
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• 2012

Crowded scenes analysis is a challenging topic in computer vision field. How to detect diverse motion patterns in crowded scenarios from videos is the critical yet hard part of this problem. In this paper, we propose a novel approach to mining motion patterns by utilizing motion information during both long-term period and short interval simultaneously. To capture long-term motions effectively, we introduce Motion History Image (MHI) representation to access to the global perspective about the crowd motion. The combination of MHI and optical flow, which is used to get instant motion information, gives rise to discriminative spatial-temporal motion features. Benefitting from the robustness and efficiency of the novel motion representation, the following motion pattern mining is implemented in a completely unsupervised way. The motion vectors are clustered hierarchically through automatic hierarchical clustering algorithm building on the basis of graphic model. This method overcomes the instability of optical flow in dealing with time continuity in crowded scenes. The results of clustering reveal the situations of motion pattern distribution in current crowded videos. To validate the performance of the proposed approach, we conduct experimental evaluations on some challenging videos including vehicles and pedestrians. The reliable detection results demonstrate the effectiveness of our approach.